"uuid","repository link","title","author","contributor","publication year","abstract","subject topic","language","publication type","publisher","isbn","issn","patent","patent status","bibliographic note","access restriction","embargo date","faculty","department","research group","programme","project","coordinates"
"uuid:2568936b-2f64-4f89-8d08-41b38e949bc0","http://resolver.tudelft.nl/uuid:2568936b-2f64-4f89-8d08-41b38e949bc0","Investigation of the first quasi-rectangular metro tunnel constructed by the 0−θ method","Li, Peinan (Donghua University); Liu, Xue (Donghua University); Jiang, Xi (University of Tennessee); Zhang, X. (TU Delft Geo-engineering); Wu, Jun (Shanghai University of Engineering Science); Chen, Peixin (Shanghai Tunnel Engineering Co. Ltd.)","","2024","Quasi-rectangular shield tunneling is a cutting-edge trenchless method for constructing metro tunnels with double tubes, owing to its advantages in saving underground space and reducing ground disturbance. However, the conventional quasi-rectangular shield tunneling method is not applicable when constructing a tunnel without a center pillar, such as a scissor crossover section of a metro line. Therefore, the 0−θ tunneling method, which combines the quasi-rectangular shield and pipe jacking methods, was investigated in this study to solve the aforementioned construction challenges. This study presents a case study of the Sijiqing Station of the Hangzhou Metro Line 9 in China, in which the 0−θ method was first proposed and applied. Key techniques such as switching between two types of tunneling modes and the tunneling process control in complex construction environments were investigated. The results demonstrated that the 0−θ method can address the technical challenges presented by the post-transition line with a high curvature and a scissors crossover line. In addition, the adoption of the 0−θ method ensured that the transformation between shield tunneling and pipe jacking was safe and efficient. The ground settlement monitoring results demonstrated that the disturbance to the surrounding environment can be limited to a safe level. This case study contributes to the construction technology for a metro tunnel containing both post-transition lines with a small turning radius and a scissors crossover line. A practical construction experience and theoretical guidance were provided in this study, which are of significance for both the industry and academia.","0−θ method; pipe jacking; quasi-rectangular tunnel; shield tunneling; underground space","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-11","","","Geo-engineering","","",""
"uuid:4b85c22f-4ed0-4fe1-a137-b064a60b0768","http://resolver.tudelft.nl/uuid:4b85c22f-4ed0-4fe1-a137-b064a60b0768","Adsorption characteristics and mechanisms of water-soluble polymers (PVP and PEG) on kaolin and montmorillonite minerals","Wang, Xintu (Guilin University of Technology; Chinese Academy of Sciences); Xu, Yanghui (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ou, Q. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Chen, Wenwen (Guilin University of Technology); van der Meer, W.G.J. (University of Twente; Oasen); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences; University of Chinese Academy of Sciences)","","2024","The excessive use and accumulation of water-soluble polymers (WSPs, known as “liquid plastics”) in the environment can pose potential risks to both ecosystems and human health, but the environmental fate of WSPs remains unclear. Here, the adsorption behavior of WSPs with different molecular weight on kaolinite (Kaol) and montmorillonite (Mt) were examined. The results showed that the adsorption of PEG and PVP on minerals were controlled by hydrogen bond and van der Waals force. The Fourier transform infrared (FTIR) spectra and two-dimensional correlation spectroscopy (2D-COS) analysis revealed that there were interactions between the Al-O and Si-O groups of the minerals and the polar O- or N-containing functional groups as well as the alkyl groups of PEG and PVP. The adsorption characteristics of WSPs were closely related to their molecular weight and the pore size of minerals. Due to the relatively large mesopore size of Kaol, both PEG and PVP were absorbed into inner spaces, for which the adsorption capacity increased with molecular weight of the polymers. For Mt, all types of PEG could enter its micropores, while PVP with larger molecular weights appeared to be confined externally, leading to a decrease in the adsorption capacity of PVP with increasing molecular weight. The findings of this study provide a theoretical basis for scientific evaluation of environmental processes of WSPs.","Adsorption; Hydrogen bond; Minerals; Molecular weight; Water-soluble polymers","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:edaba1eb-4d33-4957-b21e-f3b66e584c90","http://resolver.tudelft.nl/uuid:edaba1eb-4d33-4957-b21e-f3b66e584c90","Substrate-Specific Evolution of Amine Dehydrogenases for Accessing Structurally Diverse Enantiopure (R)-β-Amino Alcohols","Yin, Xinjian (Sun Yat-sen University); Gong, Wenzhong (Sun Yat-sen University); Zeng, Yujing (Sun Yat-sen University); Qiu, Hulin (Sun Yat-sen University); Liu, Lan (Sun Yat-sen University); Hollmann, F. (TU Delft BT/Biocatalysis); Chen, Bishuang (Sun Yat-sen University)","","2024","The biocatalytic oxidative deamination of β-amino alcohols holds significant practical potential in kinetic resolution and/or deracemization process to access (R)-β-amino alcohols. This study exemplifies a notable instance of acquisition and utilization of this valuable oxidative deamination activity. Initially, the mutation N261M (M0) was identified to endow a native valine dehydrogenase with oxidative deamination activity toward a few (S)-β-amino alcohols. Subsequently, a phylogenetic analysis-guided, double-code saturation mutagenesis strategy was proposed to engineer M0's side-chain binding site. This strategy facilitated the substrate-specific evolution of M0, resulting in the creation of a panel of mutants (M1-M4) with noteworthy oxidative deamination activity toward structurally diverse (S)-β-amino alcohols. Using these engineered amine dehydrogenases, termed as β-amino alcohol dehydrogenases (β-AADHs), the complete kinetic resolution and even deracemization of a range of β-amino alcohols have been achieved. This work reports distinct biocatalysts and a synthetic strategy for the synthesis of enantiopure (R)-β-amino alcohols and offers an innovative approach for substrate-specificity engineering of enzymes.","amine dehydrogenases; biocatalysis; enantiopure β-amino alcohols; oxidative deamination; protein engineering","en","journal article","","","","","","","","","","","BT/Biocatalysis","","",""
"uuid:6b4ae14c-fdd7-46a3-93c1-a51f4c981738","http://resolver.tudelft.nl/uuid:6b4ae14c-fdd7-46a3-93c1-a51f4c981738","FedViT: Federated continual learning of vision transformer at edge","Zuo, Xiaojiang (Beijing Institute of Technology); Luopan, Yaxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Zhang, Qinglong (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2024","Deep Neural Networks (DNNs) have been ubiquitously adopted in internet of things and are becoming an integral part of our daily life. When tackling the evolving learning tasks in real world, such as classifying different types of objects, DNNs face the challenge to continually retrain themselves according to the tasks on different edge devices. Federated continual learning (FCL) is a promising technique that offers partial solutions but yet to overcome the following difficulties: the significant accuracy loss due to the limited on-device processing, the negative knowledge transfer caused by the limited communication of non-IID (non-Independent and Identically Distributed) data, and the limited scalability on the tasks and edge devices. Moreover, existing FCL techniques are designed for convolutional neural networks (CNNs), which have not utilized the full potential of newly emerged powerful vision transformers (ViTs). Considering ViTs depend heavily on training data diversity and volume, we hypothesize ViTs are well-suited for FCL where data arrives continually. In this paper, we propose FedViT, an accurate and scalable federated continual learning framework for ViT models, via a novel concept of signature task knowledge. FedViT is a client-side solution that continuously extracts and integrates the knowledge of signature tasks which are highly influenced by the current task. Each client of FedViT is composed of a knowledge extractor, a gradient restorer and, most importantly, a gradient integrator. Upon training for a new task, the gradient integrator ensures the prevention of catastrophic forgetting and mitigation of negative knowledge transfer by effectively combining signature tasks identified from the past local tasks and other clients’ current tasks through the global model. We implement FedViT in PyTorch and extensively evaluate it against state-of-the-art techniques using popular federated continual learning benchmarks. Extensive evaluation results on heterogeneous edge devices show that FedViT improves model accuracy by 88.61% without increasing model training time, reduces communication cost by 61.55%, and achieves more improvements under difficult scenarios such as large numbers of tasks or clients, and training different complex ViT models.","Catastrophic forgetting; Continual learning; Edge computing; Federated learning; Knowledge transfer negative; Vision transformer","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-22","","","Data-Intensive Systems","","",""
"uuid:1748f6c4-08e2-4124-aee3-68398205bfaf","http://resolver.tudelft.nl/uuid:1748f6c4-08e2-4124-aee3-68398205bfaf","Tunable visible emission and persistent luminescence of BaGa2O4:Cu2+","Wang, Lei (Hefei University of Technology); Zhao, Ning (Hefei University of Technology); Zhu, Changrui (Hefei University of Technology); Chen, Lei (Hefei University of Technology); Jiang, Yang (Hefei University of Technology); Zhou, Rulong (Hefei University of Technology); Liu, Yanfang (Hefei University of Technology); Qu, Bingyan (Hefei University of Technology); Hintzen, H.T.J.M. (TU Delft RST/Luminescence Materials)","","2024","In the field of solid-state luminescence, Cu2+ has long been widely acknowledged for its capacity to emit infrared light. However, the occurrence of visible emission from Cu2+ ions had been infrequently observed and reported. In this study, we made an intriguing discovery by examining the behavior of Cu2+ within an irregular coordination environment of Ba in BaGa2O4. When excited by UV light, Cu2+ unexpectedly gave a vibrant yellow–red emission, covering a wavelength range spanning from 500 to 750 nm. More noteworthy, by simply manipulating the excitation wavelength or adjusting the temperature, the peak wavelength of the emission could be effectively tuned from approximately 600 to 660 nm, which could be attributed to the luminescence nature of the charge transfer (CT) between O2− and Cu2+. Moreover, the phosphor material displayed a remarkable persistent luminescence (PerL) lasting up to 12 h after UV light excitation. Through thermoluminescence (TL) measurements and first-principle calculations, we found that the intrinsic defects, such as vacancies of oxygen and gallium (VO and VGa″), played important roles for the PerL phenomena. These findings highlighted the exceptional tunability and PerL properties of BaGa2O4:Cu2+. Our study provided a new potential guideline for the design of Cu2+-activated phosphors in visible region, and opened up new avenues for the research in related functional luminescence materials.","Cu luminescence; Mechanism; Persistent luminescence; Phosphors; Tunable emission","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-09-01","","","RST/Luminescence Materials","","",""
"uuid:79e91102-4da0-451a-bfc3-91a951d79d34","http://resolver.tudelft.nl/uuid:79e91102-4da0-451a-bfc3-91a951d79d34","Junction temperature and luminous flux prediction for white LED array based on electrical-photo-thermal modeling","Liu, Minne (Fudan University); Li, Wenyu (Fudan University); Chen, Wei (Fudan University); Ibrahim, Mesfin S. (New Territories); Xiong, Jingkang (Changzhou Institute of Technology Research for Solid State Lighting); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, Jiajie (Fudan University; Fudan Zhangjiang Institute; Chinese Academy of Sciences)","","2024","During the operation of an LED array, its thermal and optical performances are always not equal to the superposition of the individual LED's characteristics because of a significant thermal coupling effect between the arrays. Based on this, this paper proposes an electrical–photo-thermal model, with considering both junction temperature and luminous flux, to predict the both the thermal and optical performances of LED arrays operated under different currents, case temperatures, and lighting methods. The junction temperature and luminous flux of a single LED operating under different driving currents and case temperature conditions are firstly collected to establish the luminous flux response surface model of a single chip. Then it is used to predict the luminous flux of an array, whose junction temperature is predicted using both thermal coupling matrix (TCM) and numerical models. Experiments verify the luminous flux of the LED array under different operation conditions and show that the proposed electrical–photo-thermal modeling can be used to predict the thermal and optical parameters of LED arrays with 95 % accuracy. Thus, it is effective for the fast prediction of the junction temperature and luminous flux of large LED systems with array structures, i.e. intelligent automotive lightings and displays.","Electrical-photo-thermal modeling; Junction temperature; Light-emitting diode; Luminous flux; Multiple-chip array; Thermal coupling","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:72c4f3e2-a859-4c4d-9253-b32240e7de67","http://resolver.tudelft.nl/uuid:72c4f3e2-a859-4c4d-9253-b32240e7de67","Machine learning assisted discovery of high-efficiency self-healing epoxy coating for corrosion protection","Liu, Tong (University of Science and Technology Beijing; Shenyang University of Chemical Technology); Chen, Zhuoyao (University of Science and Technology Beijing); Yang, Jingzhi (University of Science and Technology Beijing); Ma, Lingwei (University of Science and Technology Beijing; Liaoning Academy of Materials); Mol, J.M.C. (TU Delft Team Arjan Mol); Zhang, Dawei (University of Science and Technology Beijing; Liaoning Academy of Materials)","","2024","Machine learning is a powerful means for the rapid development of high-performance functional materials. In this study, we presented a machine learning workflow for predicting the corrosion resistance of a self-healing epoxy coating containing ZIF-8@Ca microfillers. The orthogonal Latin square method was used to investigate the effects of the molecular weight of the polyetheramine curing agent, molar ratio of polyetheramine to epoxy, molar content of the hydrogen bond unit (UPy-D400), and mass content of the solid microfillers (ZIF-8@Ca microfillers) on the low impedance modulus (lg|Z|0.01Hz) values of the scratched coatings, generating 32 initial datasets. The machine learning workflow was divided into two stages: In stage I, five models were compared and the random forest (RF) model was selected for the active learning. After 5 cycles of active learning, the RF model achieved good prediction accuracy: coefficient of determination (R 2) = 0.709, mean absolute percentage error (MAPE) = 0.081, root mean square error (RMSE) = 0.685 (lg(Ω·cm2)). In stage II, the best coating formulation was identified by Bayesian optimization. Finally, the electrochemical impedance spectroscopy (EIS) results showed that compared with the intact coating ((4.63 ± 2.08) × 1011 Ω·cm2), the |Z|0.01Hz value of the repaired coating was as high as (4.40 ± 2.04) × 1011 Ω·cm2. Besides, the repaired coating showed minimal corrosion and 3.3% of adhesion loss after 60 days of neutral salt spray testing.","","en","journal article","","","","","","","","","","","Team Arjan Mol","","",""
"uuid:960886bc-328f-407a-bf2c-faf9c63700df","http://resolver.tudelft.nl/uuid:960886bc-328f-407a-bf2c-faf9c63700df","Hygrothermal effects on fatigue delamination behavior in composite laminates","Yao, Liaojun (Harbin Institute of Technology); Wang, Jiexiong (Harbin Institute of Technology); He, Yonglyu (National University of Defense Technology); Zhao, Xiuhui (National University of Defense Technology); Chen, Xiangming (Aircraft Strength Research Institute); Liu, J. (Harbin Institute of Technology); Guo, Licheng (Harbin Institute of Technology); Alderliesten, R.C. (TU Delft Group Alderliesten)","","2024","Fatigue delamination growth (FDG) is an important failure in composite structures during their long-term operations. Hygrothermal aging can have significant effects on interlaminar resistance. It is therefore really necessary to explore FDG behavior in composite laminates with hygrothermal aging. Dynamic mechanical thermal analysis (DMTA), mode I FDG experiments and fractographic examinations were conducted to fully investigate hygrothermal aging effects and the corresponding mechanisms on FDG behavior. The DMTA results indicated that environmental aging can induce obvious Tg decrease. Mode I experimental fatigue data interpreted via different Paris-type correlations demonstrated that: Bridging has obvious retardation effects on FDG behavior via the Paris interpretations; The modified Paris relation can well characterize the intrinsic FDG behavior around the crack front; The use of the two-parameter Paris-type relation can appropriately account for R-ratio effects, contributing to a master resistance curve in determining mode I FDG behavior. According to these interpretations, it can be concluded that hygrothermal aging can have adverse effects on mode I FDG behavior. SEM examinations demonstrated that moisture absorption can cause fibre/matrix debonding and resin matrix pores/voids in the composite. However, no obvious difference in damage mechanisms was identified in mode I fatigue delamination for composite with/without environmental conditioning. Both fibre/matrix debonding and matrix brittle fracture were identified on fatigue fracture surfaces. Accordingly, it was concluded that fibre/matrix interface and matrix degradation induced by water absorption were the main reasons for a faster mode I fatigue crack growth in environmental aged composite.","Composite laminates; Delamination; Fatigue; Hygrothermal aging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-30","","","Group Alderliesten","","",""
"uuid:dd1db052-8834-4c07-af2b-3fe1bdeb64a6","http://resolver.tudelft.nl/uuid:dd1db052-8834-4c07-af2b-3fe1bdeb64a6","Unraveling the hydrogen sulfide aging mechanism on electrical-thermal–mechanical property degradation of sintered nanocopper interconnects used in power electronics packaging","Chen, Wei (Fudan University); Liu, Xu (Fudan University); Hu, D. (TU Delft Electronic Components, Technology and Materials); Liu, X. (TU Delft Electronic Components, Technology and Materials); Zhu, Xi (Fudan University; Research Institute of Fudan University, Ningbo); Fan, Xuejun (Lamar University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University; Research Institute of Fudan University, Ningbo)","","2024","During operation in environments containing hydrogen sulfide (H2S), such as in offshore and coastal environments, sintered nanoCu in power electronics is susceptible to degradation caused by corrosion. In this study, experimental and molecular dynamics (MD) simulation analyses were conducted to investigate the evolution and mechanism of H2S-induced corrosion of sintered nanoCu, and bulk Cu was used as the reference. The following results are obtained: (1) Both sintered nanoCu and bulk Cu reacted with O2 prior to reacting with H2S, forming Cu2O, Cu2S, CuO, and CuS. In addition, sintered nanoCu exhibited more severe corrosion. (2) For both sintered nanoCu and bulk Cu, H2S-induced corrosion resulted in the deterioration of electrical, thermal, and mechanical properties, and sintered nanoCu experienced a greater extent of deterioration. (3) As was ascertained through Reactive Force Field (ReaxFF) MD simulations, the penetration of H2S and O2 combined with the upward migration of Cu resulted in the formation of a corrosion film. In addition, compared to bulk Cu, the H2S and O2 penetration in the sintered nanoCu structure was observed to occur to a greater depth, accounting for the more pronounced performance degradation.","HS corrosion; Performance degradation; ReaxFF; Shear strength; Sintered nanocopper","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:81bbc3bc-4ecf-4606-b100-4cb7e837c29b","http://resolver.tudelft.nl/uuid:81bbc3bc-4ecf-4606-b100-4cb7e837c29b","Comprehensive properties assessment of asphalt binder under aqueous solutions with different pH values and its gradient damage behaviors","Zou, Yingxue (Wuhan University of Technology); Wu, Shaopeng (Wuhan University of Technology); Chen, Anqi (Wuhan University of Technology); Liu, Quantao (Wuhan University of Technology); Amirkhanian, Serji (University of Alabama); Xu, S. (TU Delft Materials and Environment; Wuhan University of Technology); Yang, Chao (Hubei University of Technology); Wan, Pei (Wuhan University of Technology); Xu, Haiqin (Wuhan University of Technology); Lu, Ziyu (Wuhan University of Technology)","","2024","This study characterized the morphology, high-temperature property, rheological property, adhesion, cohesion, and chemical component of asphalt binder under aqueous solutions of different pH values. Then the physicochemical properties of asphalt binder were comprehensively evaluated by the improved radar chart. The properties of asphalt binder stripped layer-by-layer were explored to elucidate its gradient damage behaviors. The results indicate that the pH 3 solution reveals the greatest impact on the morphology of 90 asphalt (90 A) and styrene-butadiene-styrene modified asphalt (SBS MA), leading to the wide cracks on 90 A and the network cracks on SBS MA. The comprehensive assessment index of 90 A exposed to pH 3, pH 5, pH 7, pH 9, and pH 11 solutions can be reduced by 20.8%, 20.2%, 1.5%, 14.0%, and 25.5%, respectively. While for SBS MA, its corresponding values variation are 23.2%, 17.7%, 4.6%, 8.7%, and 13.0%, respectively. The acid solutions significantly affect the comprehensive properties of 90 A, but their pH value has little effect. 90 A exposure to the higher pH value of alkali solution reveals the worse comprehensive properties. Acid solute and alkali solute can aggravate the effect of aqueous solution on the comprehensive properties of SBS MA, and the degree of aggravation increases with the increase of solute concentration. The properties of asphalt binders exhibit varied gradient damage behaviors under different solute environments. The most serious damage occurs at 25–50 µm of 90 A and 0–50 µm of SBS MA. This study facilitates an accurate understanding of the mechanism of pavement distresses and composition design and construction utilization of asphalt binders.","Aqueous solutions; Asphalt binder; Comprehensive assessment; Gradient damage behaviors; pH value","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-17","","","Materials and Environment","","",""
"uuid:aeb9caee-cd3f-493d-8e2f-fc9ffaba79ea","http://resolver.tudelft.nl/uuid:aeb9caee-cd3f-493d-8e2f-fc9ffaba79ea","A Control Method for Converter-interfaced Sources to Improve Operation of Directional Protection Elements","Yang, Zhe (Aalborg University); Liu, Zhou (Aalborg University); Zhang, Qi (Siemens Gamesa Renewable Energy AS); Chen, Zhe (Aalborg University); de Jesus Chavez, Jose (TU Delft Intelligent Electrical Power Grids); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2023","The traditional fault control strategy of converter-interfaced renewable energy sources (CIRESs) may bring about a lower sensitivity level or misoperation of fault component-based directional elements. To overcome this problem, a new control scheme is proposed to adjust sequence impedance angles of CIRESs by computing suitable current references of the CIRES controller. Meanwhile, these current references are maximized by an iterative algorithm to make full use of the short-circuit capacity of CIRESs. The proposed control scheme is applicable to various faulty conditions such as different fault types, power factors, weak grids, and larger fault resistances. Compared with the new directional elements that need to update protection algorithms, the proposed control strategies can make CIRESs compatible with the existing directional elements whilst the necessary fault ride-through (FRT) requirements can still be satisfied. Furthermore, all the controller parameters are not required to be revised based on the detected fault type, even with only local measured data collected. The associated PSCAD simulations, real-time digital simulator (RTDS) testing and the downscale hardware experiment verify the proposed method.","Circuit faults; converter-interfaced renewable energy sources; directional elements; Fault currents; fault ride through; Impedance; impedance angle; Power transmission lines; Security; Voltage control; Voltage measurement","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-02-06","","","Intelligent Electrical Power Grids","","",""
"uuid:2106c2f5-8a86-47f6-9f9e-10283bda8bab","http://resolver.tudelft.nl/uuid:2106c2f5-8a86-47f6-9f9e-10283bda8bab","Quantifying frequency containment reserve using cross-entropy frequency-constrained contingency-state-analysis model","Yuan, Yiping (Xi’an Jiaotong University); Liu, Zhou (Siemens Gamesa Renewable Energy); Chen, Zhe (Aalborg University); Hoej Jensen, Kim (Siemens Gamesa Renewable Energy); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2023","With the increasing penetration of converter-interfaced generators, the frequency containment reserve (FCR) from conventional generators keeps going down, leading to a potential risk of frequency instability under contingencies. Consequently, Converter-interfaced generators are required to provide FCR and participate in the corrective rescheduling. Nevertheless, how to assess the FCR and quantify the adequacy of FCR under contingencies is a big challenge in modern new power system. To address this challenge, a cross-entropy-based frequency-constrained contingency-state-analysis (FC-CSA) model is proposed in this paper. Notably, both frequency control (FC) of units (i.e., conventional synchronous generators and converter-interfaced generators), and under frequency load shedding (UFLS) are incorporated in the primary frequency response. Then a unified system frequency response (SFR) function representing frequency dynamic is derived. This SFR function is extracted and reformulated as a group of mixed-integer linear constraints and participates in the traditional CSA model. Moreover, a set of frequency dynamic indexes, i.e., Expectation of UFLS risk, Expectation of FCR from conventional and converter-interfaced generators, is extended to depict the FCR that the power system requires. These indexes are calculated by the FC-CSA in a cross-entropy-based monte carlo simulation (CE-MCs). Case studies on a modified IEEE 6-bus test system and IEEE 118-bus test system are carried out to demonstrate the effectiveness of the proposed FC-CSA model.","Contingency-State-Analysis; Cross-Entropy-based Monte Carlo simulation; Frequency Containment Reserve; Frequency Control; Under-frequency Load Shedding","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-04-20","","","Intelligent Electrical Power Grids","","",""
"uuid:22efc57b-9411-4b75-b2b0-274858635660","http://resolver.tudelft.nl/uuid:22efc57b-9411-4b75-b2b0-274858635660","How Gaps are Created during Anticipation of Lane Changes","Chen, Kequan (Southeast University); Knoop, V.L. (TU Delft Transport and Planning); Liu, Pan (Southeast University); Li, Zhibin (Southeast University); Wang, Yuxuan (Southeast University)","","2023","The pre-insertion process called anticipation is an essential component of a lane-changing manoeuvre. There is little empirical research regarding the impact of anticipation. Thus, this paper aims to explore the behaviour of the new follower (NF) in the target lane when it encounters anticipation by using new trajectory datasets. The changing magnitude of the reaction pattern is proposed to identify the NF’s behaviour. We find that the anticipation significantly affects the NF’s movement in terms of gap creation and speed reduction. Then, we conduct a detailed analysis of critical variables to reveal their relationship with the NF’s behaviour. Following this, we develop binary logistic models to predict the NF’s behaviour, resulting in a good performance. It also suggests that the NF’s behaviour is highly related to the anticipation-related variables. The transferability test results show that this model can be directly used in different locations and times with satisfactory accuracy.","Anticipation behavilour; lane-changing impact; car-following behaviour; microscopic trajectory data","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Transport and Planning","","",""
"uuid:33fe7d0c-ab76-4210-a10f-eff8a75b67c1","http://resolver.tudelft.nl/uuid:33fe7d0c-ab76-4210-a10f-eff8a75b67c1","Intermediate-mass black holes: finding of episodic, large-scale, and powerful jet activity in a dwarf galaxy","Yang, Jun (Onsala Space Observatory); Paragi, Zsolt (Joint Institute for VLBI ERIC); Frey, Sándor (Konkoly Observatory Hungarian Academy of Sciences; MTA Centre of Excellence; Eötvös University); Gurvits, L. (TU Delft Astrodynamics & Space Missions; Joint Institute for VLBI ERIC); Liao, Mai (University of Science and Technology of China); Liu, Xiang (Xinjiang Astronomical Observatory); Cui, Lang (Xinjiang Astronomical Observatory); Yang, Xiaolong (Chinese Academy of Sciences); Chen, Wen (Onsala Space Observatory; Yunnan Observatories; University of Chinese Academy of Sciences)","","2023","Dwarf galaxies are characterized by a very low luminosity and low mass. Because of significant accretion and ejection activity of massive black holes, some dwarf galaxies also host low-luminosity active galactic nuclei (AGNs). In a few dwarf AGNs, very long baseline interferometry (VLBI) observations have found faint non-thermal radio emission. SDSS J090613.77+561015.2 is a dwarf AGN owning an intermediate-mass black hole (IMBH) with a mass of MBH = 3.6+−2539 × 105M and showing a rarely seen two-component radio structure in its radio nucleus. To further probe their nature, i.e. the IMBH jet activity, we performed additional deep observations with the European VLBI Network (EVN) at 1.66 and 4.99 GHz. We find the more diffuse emission regions and structure details. These new EVN imaging results allow us to reveal a two-sided jet morphology with a size up to about 150 mas (projected length ∼140 pc) and a radio luminosity of about 3 × 1038 erg s−1. The peak feature has an optically thin radio spectrum and thus more likely represents a relatively young ejecta instead of a jet base. The EVN study on SDSS J090613.77+561015.2 demonstrates the existence of episodic, relatively large-scale, and powerful IMBH jet activity in dwarf AGNs. Moreover, we collected a small sample of VLBI-detected dwarf AGNs and investigated their connections with normal AGNs. We notice that these radio sources in the dwarf AGNs tend to have steep spectra and small linear sizes, and possibly represent ejecta from scaled-down episodic jet activity.","galaxies: active; galaxies: dwarf; galaxies: individual: SDSS J090613.77+561015.2; radio continuum: galaxies","en","journal article","","","","","","","","","","","Astrodynamics & Space Missions","","",""
"uuid:f96d1e48-1212-47aa-aaf3-a291fe45cbe7","http://resolver.tudelft.nl/uuid:f96d1e48-1212-47aa-aaf3-a291fe45cbe7","Correction: Study on the controllability of the fabrication of single-crystal silicon nanopores/nanoslits with a fast-stop ionic current-monitored TSWE method (Microsystems & Nanoengineering, (2023), 9, 1, (63), 10.1038/s41378-023-00532-0)","Hong, H. (TU Delft Electronic Components, Technology and Materials; Tsinghua University); Wei, Jiangtao (Tsinghua University); Lei, Xin (Beihang University); Chen, Haiyun (Beijing Jiaotong University); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Liu, Zewen (Tsinghua University)","","2023","Correction to: Microsystems & Nanoengineering published online 16 May 2023 Correction Following publication of the original article1, it was noticed that the phrase ‘DNA sequencing’ is incorrect, which should be replaced by ‘biosensing’. The original paper has been updated.","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:e530e4e5-8720-4d39-be12-c40466d374e0","http://resolver.tudelft.nl/uuid:e530e4e5-8720-4d39-be12-c40466d374e0","Workshop on Understanding and Mitigating Cognitive Biases in Human-AI Collaboration","Boonprakong, Nattapat (University of Melbourne); He, G. (TU Delft Web Information Systems); Gadiraju, Ujwal (TU Delft Web Information Systems); Van Berkel, Niels (Aalborg University); Wang, Danding (Chinese Academy of Sciences); Chen, Si (University of Illinois at Urbana-Champaign); Liu, Jiqun (University of Oklahoma); Tag, Benjamin (Monash University); Goncalves, Jorge (University of Melbourne); Dingler, Tilman (University of Melbourne)","Ames, Morgan (editor); Fussell, Susan (editor); Gilbert, Eric (editor); Liao, Vera (editor); Ma, Xiaojuan (editor); Page, Xinru (editor); Rouncefield, Mark (editor); Singh, Vivek (editor); Wisniewski, Pamela (editor)","2023","AI systems are increasingly incorporated into human decision-making. Yet, human decision-makers are often affected by their cognitive biases. In critical settings, such as medical diagnosis, criminal judgment, or information consumption, these cognitive biases hinder optimal decision outcomes, thereby resulting in dangerous decisions and negative societal impact. The use of AI systems can amplify and exacerbate cognitive biases in their users. In this workshop, we seek to foster discussions on ongoing research around cognitive biases in human-AI collaboration and identify future research directions to understand, quantify, and mitigate the effects of cognitive biases. We will explore cognitive biases appearing in various contexts of human-AI collaboration: what can cause them?; how can we measure, model, mitigate, and manage cognitive biases?; and how can we utilise cognitive biases for the greater good? We will reflect on workshop discussions to form a research community around cognitive biases and bias-aware systems.","Cognitive Bias; Debiasing; Human-AI Collaboration","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Web Information Systems","","",""
"uuid:086009aa-e22d-495f-912e-bea55dcee975","http://resolver.tudelft.nl/uuid:086009aa-e22d-495f-912e-bea55dcee975","An integrated EDIB model for probabilistic risk analysis of natural gas pipeline leakage accidents","Chen, Xing lin (Fuzhou University); Lin, Wei dong (Fujian Provincial Institute of Architectural Design and Research); Liu, Chun xiang (Fuzhou University); Yang, Fu qiang (Fuzhou University); Guo, Yong (Fuzhou University); Li, Xin (Fuzhou University); Yuan, S. (TU Delft Safety and Security Science); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Universiteit Antwerpen; Katholieke Universiteit Leuven)","","2023","Natural gas pipeline construction is developing rapidly worldwide to meet the needs of international and domestic energy transportation. Meanwhile, leakage accidents occur to natural gas pipelines frequently due to mechanical failure, personal operation errors, etc., and induce huge economic property loss, environmental damages, and even casualties. However, few models have been developed to describe the evolution process of natural gas pipeline leakage accidents (NGPLA) and assess their corresponding consequences and influencing factors quantitatively. Therefore, this study aims to propose a comprehensive risk analysis model, named EDIB (ET-DEMATEL-ISM-BN) model, which can be employed to analyze the accident evolution process of NGPLA and conduct probabilistic risk assessments of NGPLA with the consideration of multiple influencing factors. In the proposed integrated model, event tree analysis (ET) is employed to analyze the evolution process of NGPLA before the influencing factors of accident evolution can be identified with the help of accident reports. Then, the combination of DEMATEL (Decision-making Trial and Evaluation Laboratory) and ISM (Interpretative Structural Modeling) is used to determine the relationship among accident evolution events of NGPLA and obtain a hierarchical network, which can be employed to support the construction of a Bayesian network (BN) model. The prior conditional probabilities of the BN model were determined based on the data analysis of 773 accident reports or expert judgment with the help of the Dempster-Shafer evidence theory. Finally, the developed BN model was used to conduct accident evolution scenario analysis and influencing factor sensitivity analysis with respect to secondary accidents (fire, vapor cloud explosion, and asphyxia or poisoning). The results show that ignition is the most critical influencing factor leading to secondary accidents. The occurrence time and occurrence location of NGPLA mainly affect the efficiency of emergency response and further influence the accident consequence. Meanwhile, the weight ranking of economic loss, environmental influence, and casualties on social influence is determined with respect to NGPLAs.","Accident evolution analysis; Bayesian network; Gas leakage; Natural gas pipeline; Probabilistic risk analysis","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:a986ac42-12e1-4a21-86be-6fdef45effd8","http://resolver.tudelft.nl/uuid:a986ac42-12e1-4a21-86be-6fdef45effd8","The contribution shift of ammonia-oxidizing archaea and bacteria to ammoxidation under Ag-NPs/SWCNTs/PS-NPs stressors in constructed wetlands","Yang, X. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Guo, Fucheng (Chongqing University); Liu, Tao (Chongqing University); He, Qiang (Chongqing University); Vymazal, Jan (Czech University of Life Sciences Prague); Chen, Yi (Chongqing University)","","2023","Ammonia-oxidizing microorganisms (AOMs, archaea (AOA) and bacteria (AOB)) are primarily responsible for the ammoxidation in constructed wetlands (CWs). However, little is known about evaluating the response of AOA and AOB to engineered nanomaterials (ENMs) and quantifying the shift of their contribution to ammoxidation. Herein, we operated a series of CWs exposing to silver nanoparticles (Ag-NPs), single-walled carbon nanotubes (SWCNTs), and polystyrene nano-sized plastics (PS-NPs) with the wastewater-accumulating concentration of ENMs for 180 days. The results showed that the abundance of AOA amoA gene in situ was far lower than that of AOB, while the abundance ratio of AOA to AOB increased by 15 folds after 180-day experiment. Using DNA stable isotope probing (DNA-SIP) experiment, we found that the active AOB microbiota varied substantially but the AOA was more stable across different groups. Furthermore, the co-occurrence analysis proved that ENMs stress increased the negative coexistence pattern of AOA and AOB; predictive functional profiling showed that the ENMs enhanced the functional advantage of AOA by inhibiting AOB (mainly hydroxylamine oxidation process). Finally, the contribution of AOA increased under exposing to SWCNTs (18.35%), PS-NPs (24.92%), and Ag-NPs (32.14%) compared with control group (0.03%) for 180 days. Despite this, AOB was still the primary executant of ammoxidation in CWs. Overall, in our study, the differences in activities and contributions of AOMs were quantified in CWs, and a significantly negative coexistence relationship between AOA and AOB was revealed when exposed to emerging nanomaterials.","Ammonia-oxidizing microorganisms; Ammoxidation; Constructed wetlands; DNA-stable isotope probe; Engineered nanomaterials","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-14","","","Sanitary Engineering","","",""
"uuid:75da2cf8-4ce3-47c4-8d55-1fb275aad9d0","http://resolver.tudelft.nl/uuid:75da2cf8-4ce3-47c4-8d55-1fb275aad9d0","Interfacial Designs of MXenes for Mild Aqueous Zinc-Ion Storage","Guo, R. (TU Delft RST/Storage of Electrochemical Energy; Shaanxi Normal University); Chen, C. (TU Delft RST/Storage of Electrochemical Energy); Bannenberg, L.J. (TU Delft RID/TS/Instrumenten groep); Wang, H. (TU Delft RST/Storage of Electrochemical Energy; Donghua University); Liu, Haozhe (Student TU Delft; Shaanxi Normal University); Yu, Minghao (Technische Universität Dresden); Sofer, Zdenek (University of Chemistry and Technology Prague); Lei, Zhibin (Shaanxi Normal University); Wang, Xuehang (Donghua University)","","2023","Limited Li resources, high cost, and safety risks of using organic electrolytes have stimulated a strong motivation to develop non-Li aqueous batteries. Aqueous Zn-ion storage (ZIS) devices offer low-cost and high-safety solutions. However, their practical applications are at the moment restricted by their short cycle life arising mainly from irreversible electrochemical side reactions and processes at the interfaces. This review sums up the capability of using 2D MXenes to increase the reversibility at the interface, assist the charge transfer process, and thereby improve the performance of ZIS. First, they discuss the ZIS mechanism and irreversibility of typical electrode materials in mild aqueous electrolytes. Then, applications of MXenes in different ZIS components are highlighted, including as electrodes for Zn2+ intercalation, protective layers of Zn anode, hosts for Zn deposition, substrates, and separators. Finally, perspectives are put forward on further optimizing MXenes to improve the ZIS performance.","2D MXenes; interfacial design; mild aqueous electrolyte; Zn-ion batteries; Zn-ion capacitors","en","review","","","","","","","","","","","RST/Storage of Electrochemical Energy","","",""
"uuid:5b9a2c92-6e2f-4da6-9a7f-a598ef190c6a","http://resolver.tudelft.nl/uuid:5b9a2c92-6e2f-4da6-9a7f-a598ef190c6a","Modeling the impact of lane-changing's anticipation on car-following behavior","Chen, Kequan (Southeast University); Knoop, V.L. (TU Delft Transport and Planning); Liu, Pan (Southeast University); Li, Zhibin (Southeast University); Wang, Yuxuan (Southeast University)","","2023","Lane-changing (LC) in congested traffic has been identified as a trigger for the sudden deceleration behavior of the new follower in the target lane, leading to severe traffic disturbances. Thus, investigating the response of the new follower to an LC maneuver is an important research topic in the literature. To date, numerous efforts have been devoted to understanding the impact of the lane changer on the new follower after the insertion, while less attention has been given to this influence during the pre-insertion stage (anticipation). Therefore, this paper aims to establish a new car-following (CF) model to capture the new follower's driving behavior during anticipation. Specifically, we introduce an attention mechanism deviating from Newell's CF rules to quantify the impact of anticipation. Then, we apply a neural network with an attention layer to estimate the attention mechanism and incorporate it into the Newell CF model, which yields a new CF model, denoted as CF_Attention. Using real-world trajectory data, we design three experiments and select three representative CF models to validate the CF_Attention. The results indicate that the CF_Attention outperforms the other models in predicting the new follower's trajectory, which is not affected by the heterogeneous behavior of the new follower and the anticipation duration. Additionally, the CF_Attention is proven effective in capturing the speed-space relationship and the formation of oscillation. Finally, our transferability test suggests that the CF_Attention is promising for different locations and times without requiring retraining. The results of this study could advance the integration of the LC impact and CF behavior, and could be implemented into commercial traffic simulation programs to describe vehicle movements in traffic flow more accurately.","Anticipation; Car-following model; Lane-changing impact; Trajectory data","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-30","","","Transport and Planning","","",""
"uuid:a1317215-c660-437c-84c0-caa969b4c6f5","http://resolver.tudelft.nl/uuid:a1317215-c660-437c-84c0-caa969b4c6f5","Nanoprobes for PET/MR Imaging","Liu, Huanhuan (Zhengzhou University); Wang, R. (TU Delft RST/Applied Radiation & Isotopes); Gao, Haiyan (Zhengzhou University); Chen, Lijuan (Zhengzhou University); Li, Xiaochen (Zhengzhou University); Yu, Xuan (Zhengzhou University); Wu, Yaping (Zhengzhou University); Bai, Yan (Zhengzhou University); Wei, W. (Zhengzhou University); Wang, Meiyun (Zhengzhou University; Henan University)","","2023","The development of clinical imaging techniques significantly improves diagnostic accuracy and provides guidance for personalized treatment of individuals. However, every single imaging modality has its distinct drawbacks that cannot fully fulfil the diagnosis requirement. Thus, rational combination of different imaging modalities can achieve more comprehensive information of disease and in this way provide better personalized treatment strategy. The hybrid PET/MRI has drawn increasing attention since its first clinical application. Imaging probes play an essential role in achieving qualified figures with accurate information of diseases. The application of nanotechnology promotes the development of versatile molecular probes for PET/MRI technique. Though there is an emerging clinical requirement, only a small number of multimodal PET/MRI probes have been investigated in preclinical research. Thus, this review tries to thoroughly summarize the nano-sized PET/MRI probes on their design, preparation and biological application. By discussing the strength and limitations of these current available PET/MRI multimodal probes, this work aims to figure out the further research direction and promote the possible clinic translation of the novel PET/MRI probes.","dual-modality imaging; MRI; nanoprobes; PET; radiolabeling","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-17","","","RST/Applied Radiation & Isotopes","","",""
"uuid:ec1aca0f-2db0-4000-8bd6-65bbdd45c896","http://resolver.tudelft.nl/uuid:ec1aca0f-2db0-4000-8bd6-65bbdd45c896","A Single-Stage Three-Mode Reconfigurable Regulating Rectifier for Wireless Power Transfer","Liu, Shurui (Student TU Delft); Lu, T. (TU Delft Electronic Instrumentation); Tang, Z. (TU Delft Electronic Instrumentation); Chen, Zhiyuan (Fudan University); Jiang, Junmin (Southern University of Science and Technology); Zhao, Bo (Zhejiang University); Du, S. (TU Delft Electronic Instrumentation)","","2023","In this article, we propose a reconfigurable regulating rectifier with a wide operational range for wireless power transfer. The proposed three-mode rectifier achieves a broad range voltage regulation without global loop control to minimize the chip area occupation. Compared with previous work, more working modes and greater voltage gain allow the proposed rectifier to regulate lower input power, which extends the voltage regulation range. A local loop control scheme is proposed for voltage rectification with three modes. It adaptively senses the duty cycle of the mode signal to determine the working mode of the rectifier, and configure the rectifier to the desired mode for voltage regulation. The proposed system was designed and fabricated in a 180-nm BCD technology with an active area of 1.17 mm2. The measurement results show that the proposed system can rectify wide-range input ac power to a regulated output. The achieved voltage conversion ratiois between 0.95X and 2.68X, with a peak power conversion efficiencyat 87.4%.","Wireless power transfer; regulating rectifier; reconfigurable rectifier; implantable biomedical devices","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-10-02","","","Electronic Instrumentation","","",""
"uuid:3631b057-6e20-470a-acec-ceb3476a1137","http://resolver.tudelft.nl/uuid:3631b057-6e20-470a-acec-ceb3476a1137","3ET: Efficient Event-based Eye Tracking using a Change-Based ConvLSTM Network","Chen, Qinyu (University of Zürich; ETH Zürich); Wang, Zuowen (University of Zürich; ETH Zürich); Liu, Shih Chii (University of Zürich; ETH Zürich); Gao, C. (TU Delft Electronics)","","2023","This paper presents a sparse Change-Based Convolutional Long Short-Term Memory (CB-ConvLSTM) model for event-based eye tracking, key for next-generation wearable healthcare technology such as AR/VR headsets. We leverage the benefits of retina-inspired event cameras, namely their low-latency response and sparse output event stream, over traditional frame-based cameras. Our CB-ConvLSTM architecture efficiently extracts spatio-temporal features for pupil tracking from the event stream, outperforming conventional CNN structures. Utilizing a delta-encoded recurrent path enhancing activation sparsity, CB-ConvLSTM reduces arithmetic operations by approximately 4.7× without losing accuracy when tested on a v2e-generated event dataset of labeled pupils. This increase in efficiency makes it ideal for real-time eye tracking in resource-constrained devices. The project code and dataset are openly available at https://github.com/qinche106/cb-convlstm-eyetracking.","Pupil tracking; event cameras; sparsity; ConvLSTM; healthcare; AR/VR","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-07-18","","","Electronics","","",""
"uuid:c99e7e01-8498-4132-b86d-099d738b1332","http://resolver.tudelft.nl/uuid:c99e7e01-8498-4132-b86d-099d738b1332","A Numerical Study of Moisture and Ionic Transport in Unsaturated Concrete by Considering Multi-ions Coupling Effect","Meng, Z. (TU Delft Materials and Environment; Shanghai Jiao Tong University); Zhang, Yufei (University of Macau); Chen, Wei kang (Shanghai Jiao Tong University); Fu, Chuan qing (Zhejiang University of Technology); Xiong, Qing Xiang (Shanghai Jiao Tong University); Zhang, Cheng lin (Shanghai Jiao Tong University); Liu, Qing feng (Shanghai Jiao Tong University)","","2023","Understanding the transport mechanisms within unsaturated porous media is essential to the durability problems associated with cement-based materials. However, the involvement of multi-ions electrochemical coupling effect, especially under unsaturated condition makes the transport mechanisms even more complex. In this study, the moisture and multi-ionic transport in unsaturated concrete have been modeled in three-dimensional cases. The contribution from both water vapor and liquid has been considered in moisture transport. By adopting the constitutive electrochemical law, the electrostatic potential induced by inherent charge imbalance was calculated. With parameter calibration, the numerical results agreed well with the experimental data, proving the validity of the presented model. Results from a parametric analysis showed that neglecting multi-ions coupling effect will lead to an underestimated chloride concentration, and saturated degree has an obvious impact on the coupling strength among different ions. In addition, the existence of coarse aggregates will not only block mass transport but also make the discrepancies between two-dimensional model and three-dimensional model results more obvious. Other findings which have not been reported in existing studies are also highlighted.","Chloride transport; Heterogeneous nature; Ionic interaction; Moisture transport; Porous media","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-04-27","","","Materials and Environment","","",""
"uuid:6ad4a21e-e7e1-468a-b123-2861319a1839","http://resolver.tudelft.nl/uuid:6ad4a21e-e7e1-468a-b123-2861319a1839","Structure and dynamics of urban freight truck movements: A complex network theory perspective","Yang, Y. (TU Delft Transport and Planning; Beijing Jiaotong University); Jia, Bin (Beijing Jiaotong University; Xi'an Technological University); Yan, Xiao Yong (Beijing Jiaotong University); Chen, Y. (Beijing Jiaotong University); Tavasszy, Lorant (TU Delft Transport and Planning); de Bok, M.A. (TU Delft Transport and Planning); Bai, Zhuotong (Tsinghua University); Liu, Erjian (Beijing Jiaotong University); Gao, Ziyou (Beijing Jiaotong University)","","2023","Knowledge of the core structure and inherent dynamics of urban freight transport systems is important for the development of policies, aimed at improving the livability and sustainability of cities. The past decade has witnessed a great deal of efforts into analyzing the geographic structure of urban freight transport systems. However, in-depth studies on the system core structure and underlying dynamics are still absent. This study contributes to the field by analyzing large scale freight truck trip data from Chinese cities, using complex network analysis. We empirically reconstruct and characterize the urban freight truck mobility networks and reveal the underlying spatial interaction patterns. We develop a spatial network growth model which explains how hub-and-spoke core structure of urban freight transport systems are formed. The developed model captures the essential interaction dynamics of freight locations, and explains the effects of spatial distance, economic size and business pattern replication. Inspired by the model, we provide policy implications for land-use planning, transportation planning and sustainable urban development.","Complex networks; Freight truck flows; Interaction dynamics; Structure properties; Urban freight transport system","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-02","","","Transport and Planning","","",""
"uuid:7a749410-3d5d-4619-9f4b-94d57616fe6d","http://resolver.tudelft.nl/uuid:7a749410-3d5d-4619-9f4b-94d57616fe6d","Simplex-based multinomial logistic regression with diverging numbers of categories and covariate","Fu, Sheng (National University of Singapore); Chen, P. (TU Delft Statistics); Liu, Yufeng (University of North Carolina); Ye, Zhisheng (National University of Singapore)","","2023","Multinomial logistic regression models are popular in multicategory classification analysis, but existing models suffer several intrinsic drawbacks. In particular, the parameters cannot be determined uniquely because of the over-specification. Although additional constraints have been imposed to refine the model, such modifications can be inefficient and complicated. In this paper, we propose a novel and efficient simplex-based multinomial logistic regression technique, seamlessly connecting binomial and multinomial cases under a unified framework. Compared with existing models, our model has fewer parameters, is free of any constraints, and can be solved efficiently using the Fisher scoring algorithm. In addition, the proposed model enjoys several theoretical advantages, including Fisher consistency and sharp comparison inequality. Under mild conditions, we establish the asymptotical normality and convergence for the new model, even when the numbers of categories and covariates increase with the sample size. The proposed framework is illustrated by means of extensive simulations and real applications.","Asymptotics; classification; Fisher consistency; kernel learning; MLR; simplex coding scheme","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-03-01","","","Statistics","","",""
"uuid:f03a92f6-37ee-4ac5-97cd-2501401fd19f","http://resolver.tudelft.nl/uuid:f03a92f6-37ee-4ac5-97cd-2501401fd19f","A novel lattice model to predict chloride diffusion coefficient of unsaturated cementitious materials based on multi-typed pore structure characteristics","Tong, Liang-yu (Shanghai Jiao Tong University); Xiong, Qing Xiang (Shanghai Jiao Tong University); Zhang, Zhidong (ETH Zürich); Chen, Xiangsheng (Shenzhen University); Ye, G. (TU Delft Materials and Environment); Liu, Qing feng (Shanghai Jiao Tong University)","","2023","This paper develops a novel lattice diffusive model to quantitatively study the chloride diffusion coefficient in unsaturated cementitious materials, in which the pore voxels are redistributed to make a better representation of a real microstructure of hardened cement paste. Considering the hierarchical microstructure and different drying-wetting cycles, water distributions in multiscale pore structures are modelled and the structure characteristics of water-filled pores, including water connectivity, water tortuosity and effective porosity, are computationally extracted based on that. A lattice diffusion network is established to predict relative chloride diffusion coefficient by combining the effect of both water saturation degree and pore structure characteristics. The predicted results are validated against experimental data, and a concise analytical equation is proposed to predict the relative chloride diffusion coefficient. The equation indicated that the relative chloride diffusion coefficient is proportional to water connectivity but inversely proportional to the square of water tortuosity. Besides, the lattice model's quantitative results reveal that the water connectivity and water tortuosity are highly related to pre-water loading processes, and influenced by the gel pore fraction, which in turn will affect the relative chloride diffusion coefficient. Compared with existing equations and non-redistributed models, the present model could improve the prediction accuracy significantly.","Cementitious materials; Chloride diffusion; Drying-wetting process; Lattice model; Pore structure","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-06-07","","","Materials and Environment","","",""
"uuid:4db85814-789b-4bea-8d22-37245045117e","http://resolver.tudelft.nl/uuid:4db85814-789b-4bea-8d22-37245045117e","Degradation of alkali-activated slag subjected to water immersion","Liu, C. (TU Delft Materials and Environment); Liang, X. (TU Delft Materials and Environment); Chen, Y. (TU Delft DC systems, Energy conversion & Storage; South China University of Technology); Li, Z. (TU Delft Materials and Environment; University of Sheffield); Ye, G. (TU Delft Materials and Environment)","","2023","In this study, the impacts of tap water immersion on the pore solution, phase assemblages, gel chemistry and structure, and pore structure of alkali-activated slag (AAS) pastes were studied. AAS degrades under such condition and the potential mechanisms can be concluded as lower reaction rates, gel decomposition and carbonation. The leaching of Na+ and OH− at early stages hinders the reaction of slag, which leads to a slower formation of reaction products. Long-term leaching can result in gel decomposition after 90 d. Coarsened gel pores and capillary pores are both identified in water-immersed samples. Additionally, the leached Ca2+ can react with the dissolved CO2 in tap water to form calcium carbonate. A calcium carbonate layer is observed surrounding the paste while the inner matrix is free of carbonation. The insights provided by this paper contribute to understanding the behaviors and durability of AAS in underwater conditions.","Alkali-activated slag; Carbonation; Curing; Leaching; Water immersion","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-30","","","Materials and Environment","","",""
"uuid:26c0c979-5676-4119-853c-82fcedf655b4","http://resolver.tudelft.nl/uuid:26c0c979-5676-4119-853c-82fcedf655b4","Why do major chemical accidents still happen in China: Analysis from a process safety management perspective","Bai, Mingqi (China University of Petroleum (East China)); Qi, Meng (China University of Petroleum (East China)); Shu, Chi Min (National Yunlin University of Science and Technology); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science); Khan, Faisal (Texas A and M University); Chen, Chao (Southwest Petroleum University); Liu, Yi (China University of Petroleum (East China))","","2023","As an important consideration in the chemical industry, chemical process safety has received notable attention in China. However, catastrophic chemical accidents still occur. To better understand why accidents continue to occur, this paper presented a diagnostic analysis of 14 major chemical accidents in China from 2012 to 2022 based on VOSviewer software. The authors analysed the correlation between the accident causation and their relationship with the safety management elements. The study observed that inferior process safety culture, intentional violation (rule-breaking) of procedure, inadequate safety training, and illegal operations were the most frequent causes of accidents. These causes highlighted the prominent gaps in PSM in China in the process safety culture, compliance with standards, the conduct of operations, process safety competency, and training & performance assurance. The results based on co-occurrence analysis indicated a strong correlation between these gaps in PSM. Enterprises should pay attention to collaborative management among them. These deficiencies in the enterprise's PSM system showed that the essential defects in China's chemical industry are a poor safety culture, inadequate accident investigation, inadequate training, and a lack of chemical safety personnel. The study recommended that the chemical industry establish superior process safety culture and competency for all personnel, monitor leading and lagging process safety indicators, apply inherent safety, and practice advanced safety management concepts. We hope that the findings can provide China's perspectives and strengths for global chemical safety.","Accident causation; Accident investigation; Chemical process safety; Process safety culture; Safety management elements","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-16","","","Safety and Security Science","","",""
"uuid:88d92b03-24c7-46c8-a31a-072c75245515","http://resolver.tudelft.nl/uuid:88d92b03-24c7-46c8-a31a-072c75245515","Fast DRL-based scheduler configuration tuning for reducing tail latency in edge-cloud jobs","Wen, Shilin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2023","Edge-cloud applications are rapidly prevailing in recent years and pose the challenge of using both resource-strenuous edge devices and elastic cloud resources under dynamic workloads. Efficient resource allocation on edge-cloud jobs via cluster schedulers (e.g. Kubernetes/Volcano scheduler) is essential to guarantee their performance, e.g. tail latency, and such allocation is sensitive to scheduler configurations such as applied scheduling algorithms and task restart/discard policy. Deep reinforcement learning (DRL) is increasingly applied to optimize scheduling decisions. However, DRL faces the conundrum of achieving high rewards at a dauntingly long training time (e.g. hours or days), making it difficult to tune the scheduler configurations online in accordance to dynamically changing edge-cloud workloads and resources. For such an issue, this paper proposes EdgeTuner, a fast scheduler configuration tuning approach that efficiently leverages DRL to reduce tail latency of edge-cloud jobs. The enabling feature of EdgeTuner is to effectively simulate the execution of edge-cloud jobs under different scheduler configurations and thus quickly estimate these configurations’ influence on job performance. The simulation results allow EdgeTuner to timely train a DRL agent in order to properly tune scheduler configurations in dynamic edge-cloud environment. We implement EdgeTuner in both Kubernetes and Volcano schedulers and extensively evaluate it on real workloads driven by Alibaba production traces. Our results show that EdgeTuner outperforms prevailing scheduling algorithms by achieving much lower tail latency while accelerating DRL training speed by an average of 151.63x.","DRL; Edge-cloud jobs; Kubernetes and Volcano; Scheduler configurations; Tail latency","en","journal article","","","","","","","","","","","Data-Intensive Systems","","",""
"uuid:1a997c5a-df01-48f8-b5ad-aea533d854ea","http://resolver.tudelft.nl/uuid:1a997c5a-df01-48f8-b5ad-aea533d854ea","Highly efficient carbon assimilation and nitrogen/phosphorus removal facilitated by photosynthetic O2 from algal-bacterial aerobic granular sludge under controlled DO/pH operation","Li, Zejiao (University of Tsukuba); Wang, Jixiang (University of Tsukuba); Liu, Jialin (University of Tsukuba); Chen, Xingyu (University of Tsukuba); Lei, Zhongfang (University of Tsukuba); Yuan, Tian (University of Tsukuba); Lee, Duu Jong (City University of Hong Kong; Yuan Ze University, Chung-Li); Lin, Y. (TU Delft Environmental Fluid Mechanics); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2023","Reducing CO2 emission and energy consumption is crucial for the sustainable management of wastewater treatment plants (WWTPs). In this study, an algal-bacterial aerobic granular sludge (AGS) system was developed for efficient carbon (C) assimilation and nitrogen (N)/phosphorus (P) removal without the need for mechanical aeration. The photosynthetic O2 production by phototrophic organisms maintained the dissolved oxygen (DO) level at 3-4 mg/L in the bulk liquid, and an LED light control system reduced 10–30% of light energy consumption. Results showed that the biomass assimilated 52% of input dissolved total carbon (DTC), and the produced O2 simultaneously facilitated aerobic nitrification and P uptake with the coexisting phototrophs serving as a C fixer and O2 supplier. This resulted in a stably high total N removal of 81 ± 7% and an N assimilation rate of 7.55 mg/(g-MLVSS∙d) with enhanced microbial assimilation and simultaneous nitrification/denitrification. Good P removal of 92–98% was maintained during the test period at a molar ∆P/∆C ratio of 0.36 ± 0.03 and high P release and uptake rates of 10.84 ± 0.41 and 7.18 ± 0.24 mg/(g- MLVSS∙h), respectively. Photosynthetic O2 was more advantageous for N and P removal than mechanical aeration. This proposed system can contribute to a better design and sustainable operation of WWTPs using algal-bacterial AGS.","Algal-bacterial aerobic granular sludge; Carbon fixation; Nitrogen assimilation; Photosynthetic oxygen; Simultaneous nitrogen and phosphorus removal","en","journal article","","","","","","","","2023-12-30","","","Environmental Fluid Mechanics","","",""
"uuid:16547a07-b17b-4690-881a-ce5fd280a91e","http://resolver.tudelft.nl/uuid:16547a07-b17b-4690-881a-ce5fd280a91e","Study on the controllability of the fabrication of single-crystal silicon nanopores/nanoslits with a fast-stop ionic current-monitored TSWE method","Hong, H. (TU Delft Electronic Components, Technology and Materials; Tsinghua University); Wei, Jiangtao (Tsinghua University); Lei, Xin (Beihang University); Chen, Haiyun (Beijing Jiaotong University); Sarro, Pasqualina M (TU Delft Electronic Components, Technology and Materials); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Liu, Zewen (Tsinghua University)","","2023","The application of single-crystal silicon (SCS) nanopore structures in single-molecule-based analytical devices is an emerging approach for the separation and analysis of nanoparticles. The key challenge is to fabricate individual SCS nanopores with precise sizes in a controllable and reproducible way. This paper introduces a fast-stop ionic current-monitored three-step wet etching (TSWE) method for the controllable fabrication of SCS nanopores. Since the nanopore size has a quantitative relationship with the corresponding ionic current, it can be regulated by controlling the ionic current. Thanks to the precise current-monitored and self-stop system, an array of nanoslits with a feature size of only 3 nm was obtained, which is the smallest size ever reported using the TSWE method. Furthermore, by selecting different current jump ratios, individual nanopores of specific sizes were controllably prepared, and the smallest deviation from the theoretical value was 1.4 nm. DNA translocation measurement results revealed that the prepared SCS nanopores possessed the excellent potential to be applied in DNA sequencing. [Figure not available: see fulltext.]","","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:51aea123-9bad-4e6f-83db-83ebd2b716ee","http://resolver.tudelft.nl/uuid:51aea123-9bad-4e6f-83db-83ebd2b716ee","Experimental and numerical study on the mitigation of autogenous shrinkage of cementitious material","Lu, T. (TU Delft Materials and Environment; Southwest Petroleum University); Liang, X. (TU Delft Materials and Environment); Liu, C. (TU Delft Materials and Environment); Chen, Y. (TU Delft Materials and Environment; South China University of Technology); Li, Z. (University of Sheffield)","","2023","This study experimentally investigated the effects of surfactants and water-repelling agents on the hydration process, relative humidity, and mechanical properties of Portland cement pastes. Based on the measurement results, the degree of hydration, degree of saturation, capillary tension of autogenous shrinkage, and magnitude of autogenous shrinkage were simulated using a numerical model. In the numerical model, the elastic and creep components of autogenous shrinkage were calculated separately, and the creep component was simulated based on the solidification theory. The simulation results indicated that adding admixtures led to lower degrees of hydration and saturation. The capillary tension of the pure Portland cement was larger than that of the other mixtures. This can be attributed to several factors, including the smaller surface tension of mixtures with surfactants, larger contact angle of mixtures with water-repelling agents, and a lower degree of hydration of mixtures with both admixtures. Analyses of the simulated and measured results for different mixtures also show that creep plays an indispensable role in autogenous shrinkage. Adding a surfactant and a water-repelling agent can effectively mitigate autogenous shrinkage. However, when an excessive amount of water-repelling agent was added, its influence on the mitigation of autogenous shrinkage was insignificant.","Autogenous shrinkage; Cement paste; Simulation; Surfactant; Water-repelling agent","en","journal article","","","","","","","","","","","Materials and Environment","","",""
"uuid:4d82e915-6953-4ba1-9266-3dada5a3b692","http://resolver.tudelft.nl/uuid:4d82e915-6953-4ba1-9266-3dada5a3b692","Fatigue delamination behavior in composite laminates at different stress ratios and temperatures","Yao, Liaojun (Harbin Institute of Technology); Chuai, Mingyue (Harbin Institute of Technology); Liu, J. (Harbin Institute of Technology); Guo, Licheng (Harbin Institute of Technology); Chen, Xiangming (Aircraft Strength Research Institute); Alderliesten, R.C. (TU Delft Structural Integrity & Composites; Structural Integrity and Composite Group); Beyens, M. (Student TU Delft)","","2023","This study provides an investigation on mode I fatigue delamination growth (FDG) with fibre bridging at different R-ratios and temperatures in carbon-fibre reinforced polymer composites. FDG experiments were first conducted at different temperatures of R-ratios 0.1 and 0.5 via unidirectional double cantilever beam (DCB) specimens. A fatigue model, employing both the strain energy release rate (SERR) range and the maximum SERR around crack front as similitude parameter, was proposed to interpret FDG behavior. The use of this model can collapse FDG data with fibre bridging at different R-ratios into one master curve, obeying well with the similitude principles. Accordingly, it was found that FDG can accelerate with elevated temperature, but decrease at sub-zero temperature. Furthermore, there are strong correlations between the fatigue model parameters and temperature using this model in FDG interpretations. Taking these correlations into account can extend the model to accurately predict FDG behavior of other temperatures. Fractographic examinations demonstrated that temperature has effects on the FDG damage mechanisms. Both fibre/matrix interfacial debonding and matrix brittle failure were observed in FDG of −40℃. Fibre/matrix interfacial debonding becomes the dominant failure in FDG of RT and 80℃. No obvious difference on the fracture morphology was identified for FDG at different R-ratios of a given temperature.","Composite laminates; Fatigue delamination; Fibre bridging; R-ratio; Temperature","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-08","","","Structural Integrity & Composites","","",""
"uuid:78e9a0c9-5ff6-403a-874a-2912bef64569","http://resolver.tudelft.nl/uuid:78e9a0c9-5ff6-403a-874a-2912bef64569","Analysis of the cohesion/adhesion proportion around bitumen-mineral failure interface under tensile loading","Shi, Baocun (Hohai University); Liu, Quan (Hohai University); Gao, Y. (TU Delft Pavement Engineering); Wu, Jiantao (Hohai University); Chen, Jingya (Hohai University)","","2023","The occurrence of cohesive/adhesive hybrid failure at the bitumen-aggregate interface is widely acknowledged, however, the quantitative evaluation of the cohesion/adhesion proportion is relatively weak. This study explored cohesive/adhesive hybrid failure and provided a quantitative analysis of the proportion between cohesion and adhesion. For this reason, this study considered a variety of experimental factors that included temperature (5 °C, 15 °C, and 25 °C), mineral morphology (three mineral types and three surface textures), and measured film thickness (varying from 10 μm to 900 μm). By performing the bonding strength test, the strength was recorded and interface failure was accordingly captured. The results indicated that the cohesion/adhesion proportion varied significantly with the temperature, mineral morphology, and measured film thickness. In addition, it was found that bonding strength decreased with the increase in the film thickness and temperature, which can be well explained by variation in adhesion/cohesion proportion. Complete cohesive failure was observed when the film thickness increased beyond a critical value at a relatively high temperature. An additional noteworthy finding was the resemblance of a lunar crater for the failure interface at high temperatures, signifying the heterogeneous composition of the bituminous binder around the interface.","Adhesion/cohesion proportion; Bitumen-aggregate interface; Failure mode; Film thickness; Mineral surface morphology","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-22","","","Pavement Engineering","","",""
"uuid:479160cf-358f-40a2-a925-e5ad08fd9851","http://resolver.tudelft.nl/uuid:479160cf-358f-40a2-a925-e5ad08fd9851","Microstructural evolutions and impact toughness in simulated welding heat affected zones for a high-strength carbide-free bainitic rail steel","Bai, Wei (Southwest Jiaotong University; State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization); Xu, X. (TU Delft Novel Aerospace Materials; Southwest Jiaotong University); Liu, Yaolan (Southwest Jiaotong University); Liang, Yunxiao (Southwest Jiaotong University); Shen, Yijie (Southwest Jiaotong University); Han, Zhenyu (State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization); Sheng, Zhendong (State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization); Chen, Rong (State Key Laboratory of Vanadium and Titanium Resources Comprehensive Utilization); Zhu, Minhao (Southwest Jiaotong University)","","2023","Systematic experimental investigations were conducted to study the microstructures and impact toughness of each heat affected zone (HAZ) formed during rail flash-butt welding. A high-strength carbide-free bainitic rail steel was subjected to different thermal simulation cycles to separately reproduce each HAZ subzone by tailoring the peak temperature (PT) with respect to 700, 850, 920, 1000 and 1350 °C, and hence to generate the corresponding microstructures by using Gleeble-3500 simulator. Results show that the HAZ subzones exhibit complicated microstructures depending on the PTs, and with increasing PT the dominant bainitic microstructure type evolves from polygonal bainitic ferrite (700 °C) to a mixture of fine bainitic ferrite and granular bainite (850–1000 °C), and finally to coarse bainitic ferrite and granular bainite (1350 °C). Impact tests demonstrate that the impact toughness initially increases significantly as the PT reaches 920 °C (i.e., fine-grained HAZ), beyond which the impact toughness starts to decrease. The fine-grained HAZ displays optimal impact toughness in HAZs, yet which is lower than the base metal. Moreover, the morphology and distribution of martensite-austenite (M-A) constituents is strongly dependent on the welding PT, and the high fraction blocky and coarse slender M-A constituents is considered to be detrimental for the impact toughness.","Bainitic rail steel; Impact toughness; Microstructural evolutions; Peak temperature; Welding thermal simulation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-12-25","","","Novel Aerospace Materials","","",""
"uuid:046880f9-39e1-44e3-8138-ffe45babfb8c","http://resolver.tudelft.nl/uuid:046880f9-39e1-44e3-8138-ffe45babfb8c","Solvent modulation, microstructure evaluation, process optimization, and nanoindentation analysis of micro-Cu@Ag core–shell sintering paste for power electronics packaging","Chen, Haixue (Fudan University); Wang, Xinyue (Fudan University); Zeng, Zejun (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Zhang, Jing (Heraeus Materials Technology); Liu, Pan (Fudan University; Research Institute of Fudan University, Ningbo)","","2023","With the development of electronic technology towards high power, miniaturization, and system integration, power electronic packaging is facing increasing challenges, especially for die attachment. This research aims to explore silver-coated copper (Cu@Ag) paste with sufficient mechanical properties and high-temperature reliability, as an alternative solution for silver sintering with lower cost. Firstly, micro-Cu@Ag sintering pastes were investigated under four kinds of polyol-based solvent systems and two types of particle morphologies, which included sphere-type (SCu@Ag) and flake-type (FCu@Ag). Sintering performance and microstructural evolution were compared and analyzed. Notably, sintered joints employing the terpineol–polyethylene glycol solvent system and flake-type morphology displayed a denser microstructure in comparison to SCu@Ag joints. Its bonding strength reached 36.15 MPa, which was approximately 20% higher than SCu@Ag joints. Subsequently, the influence of key sintering process parameters on Cu@Ag joints was analyzed, including sintering temperature, pressure and time. Additionally, high-temperature aging and thermal cycling tests were conducted on the optimized Cu@Ag joints to assess their reliability. Finally, the micromechanical properties of Cu@Ag joints before and after high-temperature aging were further evaluated by nanoindentation including creep properties. The elastoplastic constitutive models of Cu@Ag sintered materials with different particle morphologies were constructed, providing valuable insights for reliability evaluation. The results indicated that FCu@Ag joints exhibited satisfactory creep resistance and high-temperature reliability. In conclusion, the FCu@Ag micro-paste based on the terpineol–polyethylene glycol solvent system proposed in this study demonstrated sufficient bonding strength, high reliability, and adequate mechanical properties as an attractive solution for high-temperature power electronics packaging.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-21","","","Electronic Components, Technology and Materials","","",""
"uuid:099f0ca9-d50b-49a4-a728-dc494310a664","http://resolver.tudelft.nl/uuid:099f0ca9-d50b-49a4-a728-dc494310a664","Gate-tunable superconductivity in hybrid InSb-Pb nanowires","Chen, Yan (University of Copenhagen); van Driel, D. (TU Delft QRD/Kouwenhoven Lab; Kavli institute of nanoscience Delft; QuTech); Lampadaris, Charalampos (University of Copenhagen); Khan, Sabbir A. (University of Copenhagen; Danish Fundamental Metrology, Horsholm); Alattallah, Khalifah (University of Copenhagen); Zeng, Lunjie (Chalmers University of Technology); Olsson, Eva (Chalmers University of Technology); Dvir, T. (TU Delft Qubit Research Division; Kavli institute of nanoscience Delft; QuTech); Krogstrup, Peter (University of Copenhagen); Liu, Yu (University of Copenhagen)","","2023","We present a report on hybrid InSb-Pb nanowires that combine high spin-orbit coupling with a high critical field and a large superconducting gap. Material characterization indicates the Pb layer of high crystal quality on the nanowire side facets. Hard induced superconducting gaps and gate-tunable supercurrent are observed in the hybrid nanowires. These results showcase the promising potential of this material combination for a diverse range of applications in hybrid quantum transport devices.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-02-21","","Qubit Research Division","QRD/Kouwenhoven Lab","","",""
"uuid:580e5a49-5028-45fa-bcf6-0747836ecf40","http://resolver.tudelft.nl/uuid:580e5a49-5028-45fa-bcf6-0747836ecf40","An Area-Efficient Ultra-Low-Power Time-Domain Feature Extractor for Edge Keyword Spotting","Chen, Qinyu (University of Zürich); Chang, Yaoxing (University of Zürich); Kim, Kwantae (University of Zürich); Gao, C. (TU Delft Electronics); Liu, Shih Chii (University of Zürich)","","2023","Keyword spotting (KWS) is an important task on edge low-power audio devices. A typical edge KWS system consists of a front-end feature extractor which outputs mel-scale frequency cepstral coefficients (MFCC) features followed by a back-end neural network classifier. KWS edge designs aim for the best power-performance-area metrics. This work proposes an area-efficient ultra-low-power time-domain infinite impulse response (IIR) filter-based feature extractor for a KWS system. It uses a serial architecture, and the architecture is further optimized for a low-cost computing structure and mixed-precision bit selection of the IIR coefficients while maintaining good KWS accuracy. Using a 65 nm process technology and a back-end neural network classifier, this simulated feature extractor has an area of 0.02 mm2 and achieves 3.3 μW @ 1.2 V, and achieves 92.5% accuracy on a 10-keyword, 12-class KWS task using the GSCD dataset.","hardware acceleration; infinite impulse response (IIR); Keyword spotting (KWS); long short-term memory","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-22","","","Electronics","","",""
"uuid:efae1187-df0b-4dc0-8eb0-b72f36048a9d","http://resolver.tudelft.nl/uuid:efae1187-df0b-4dc0-8eb0-b72f36048a9d","Effect of epoxy resin addition on properties and corrosion behavior of sintered joints in power modules serviced offshore","Wang, Xinyue (Fudan University); Yang, Zhoudong (Fudan University); Wang, Boya (Fudan University); Chen, Wei (Fudan University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Zhang, Jing (Heraeus Materials Technology Shanghai Ltd.); Fan, J. (TU Delft Electronic Components, Technology and Materials; Fudan University); Liu, P. (TU Delft Electronic Components, Technology and Materials; Fudan University)","","2023","Power modules applied in offshore applications are facing risks of corrosion failures on die-attach materials due to high humidity and H2S exposure. To investigate such corrosion behavior for sintered die-attach materials, we conducted a study with four groups of samples fabricated using copper and silver metal particles under different solvent systems. Such samples were firstly subjected to high-humidity-H2S conditions for 168 h to simulate the harsh offshore environment. After undergoing corrosion, the primary compounds formed were CuO/Cu2O and Ag2S through SEM, XRD, and XPS analysis. Notably, the incorporation of epoxy resin into sintered copper joints resulted in a remarkable reduction in corrosion and a substantial improvement in electrical conductivity after the reaction. In contrast, while the addition of epoxy did not evidently reduce corrosion in silver joints, it did lead to a significant increase in shear strength. Furthermore, to gain further insights into the effect of epoxy resin on corrosion behavior, electrochemical analysis, and molecular dynamics simulations were conducted. Finally, the mechanical reliability of the corroded copper and silver joints was evaluated through thermal shock tests. In summary, sintered copper joints exhibited better anti-corrosion behaviors than sintered silver under high humidity and H2S exposure, especially with the addition of epoxy resin. However, the corrosion products of sintered copper suffered from a sharp decrease in shear strength after thermal shock tests than sintered silver, which is probably due to the coefficient of thermal expansion mismatch.","Die-attach; Electrochemical analysis; Gas corrosion; Molecular dynamics simulation; Power module packaging; Sintered joint","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:20817bd2-c257-48d8-8efe-0a55993f3fe0","http://resolver.tudelft.nl/uuid:20817bd2-c257-48d8-8efe-0a55993f3fe0","FedKNOW: Federated Continual Learning with Signature Task Knowledge Integration at Edge","Luopan, Yaxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Zhang, Qinglong (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2023","Deep Neural Networks (DNNs) have been ubiquitously adopted in internet of things and are becoming an integral of our daily life. When tackling the evolving learning tasks in real world, such as classifying different types of objects, DNNs face the challenge to continually retrain themselves according to the tasks on different edge devices. Federated continual learning is a promising technique that offers partial solutions but yet to overcome the following difficulties: the significant accuracy loss due to the limited on-device processing, the negative knowledge transfer caused by the limited communication of non-IID data, and the limited scalability on the tasks and edge devices. In this paper, we propose FedKNOW, an accurate and scalable federated continual learning framework, via a novel concept of signature task knowledge. FedKNOW is a client side solution that continuously extracts and integrates the knowledge of signature tasks which are highly influenced by the current task. Each client of FedKNOW is composed of a knowledge extractor, a gradient restorer and, most importantly, a gradient integrator. Upon training for a new task, the gradient integrator ensures the prevention of catastrophic forgetting and mitigation of negative knowledge transfer by effectively combining signature tasks identified from the past local tasks and other clients' current tasks through the global model. We implement FedKNOW in PyTorch and extensively evaluate it against state-of-the-art techniques using popular federated continual learning benchmarks. Extensive evaluation results on heterogeneous edge devices show that FedKNOW improves model accuracy by 63.24% without increasing model training time, reduces communication cost by 34.28%, and achieves more improvements under difficult scenarios such as large numbers of tasks or clients, and training different complex networks.","communication; continual learning; deep neural networks; Federated learning","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-26","","","Data-Intensive Systems","","",""
"uuid:49124128-422f-4f6e-8ef2-45142046fe5d","http://resolver.tudelft.nl/uuid:49124128-422f-4f6e-8ef2-45142046fe5d","EdgeVisionBench: A Benchmark of Evolving Input Domains for Vision Applications at Edge","Zhang, Qinglong (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2023","Vision applications powered by deep neural networks (DNNs) are widely deployed on edge devices and solve the learning tasks of incoming data streams whose class label and input feature continuously evolve, known as domain shift. Despite its prominent presence in real-world edge scenarios, existing benchmarks used by domain adaptation methods overlook evolving domains and under represent their shifts in label and feature distributions. To address this gap, we present EdgeVisionBench, a benchmark seeking to generate evolving domains of various types and reflect their realistic label and feature shifts encountered by edge-based vision applications. To facilitate evaluating domain adaptation methods on edge devices, we provide an open-source package that automates workload generation, contains popular DNN models and compression techniques, and standardizes evaluations with interactive interfaces. Code and datasets are available at https://github.com/LINC-BIT/EdgeVisionBench.","benchmark; Edge computing; evolving domains; vision applications","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-26","","","Data-Intensive Systems","","",""
"uuid:311c668f-8cb7-4201-8105-c19ab87aa888","http://resolver.tudelft.nl/uuid:311c668f-8cb7-4201-8105-c19ab87aa888","Benchmarking Robustness and Generalization in Multi-Agent Systems: A Case Study on Neural MMO","Chen, Yangkun (Tsinghua University; Parametrix.ai); Yu, Chenghui (Tsinghua University; Parametrix.ai); Zhu, Hengman (Parametrix.ai); Liu, Shuai (Bilibili); Zhang, Yibing (Chengdu Goldwin Electronics Technology); Suarez, Joseph (Massachusetts Institute of Technology); Zhao, Liang (International Digital Economy Academy); He, J. (TU Delft Interactive Intelligence); Chen, Jiaxin (Parametrix.ai)","","2023","We present the results of the second Neural MMO challenge, hosted at IJCAI 2022, which received 1600+ submissions. This competition targets robustness and generalization in multi-agent systems: participants train teams of agents to complete a multi-task objective against opponents not seen during training. We summarize the competition design and results and suggest that, considering our work as a case study, competitions are an effective approach to solving hard problems and establishing a solid benchmark for algorithms. We will open-source our benchmark including the environment wrapper, baselines, a visualization tool, and selected policies for further research.","Benchmark; Competition; Multi-agent Reinforcement Learning","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-27","","","Interactive Intelligence","","",""
"uuid:3e54aaa0-46f8-4411-a5ca-351a314d73ce","http://resolver.tudelft.nl/uuid:3e54aaa0-46f8-4411-a5ca-351a314d73ce","The Multimodal Information Based Speech Processing (Misp) 2022 Challenge: Audio-Visual Diarization And Recognition","Wang, Zhe (University of Science and Technology of China); Wu, Shilong (University of Science and Technology of China); Chen, Hang (University of Science and Technology of China); He, Mao-Kui (University of Science and Technology of China); Du, Jun (University of Science and Technology of China); Lee, Chin-Hui (Georgia Institute of Technology); Chen, Jingdong (Northwestern Polytechnical University); Watanabe, Shinji (Carnegie Mellon University); Siniscalchi, Sabato Marco (Georgia Institute of Technology; University of Enna Kore); Scharenborg, O.E. (TU Delft Multimedia Computing); Liu, Diyuan (iFlytek)","","2023","The Multi-modal Information based Speech Processing (MISP) challenge aims to extend the application of signal processing technology in specific scenarios by promoting the research into wake-up words, speaker diarization, speech recognition, and other technologies. The MISP2022 challenge has two tracks: 1) audio-visual speaker diarization (AVSD), aiming to solve ""who spoken when"" using both audio and visual data; 2) a novel audio-visual diarization and recognition (AVDR) task that focuses on addressing ""who spoken what when"" with audio-visual speaker diarization results. Both tracks focus on the Chinese language, and use far-field audio and video in real home-tv scenarios: 2-6 people communicating each other with TV noise in the background. This paper introduces the dataset, track settings, and baselines of the MISP2022 challenge. Our analyses of experiments and examples indicate the good performance of AVDR baseline system, and the potential difficulties in this challenge due to, e.g., the far-field video quality, the presence of TV noise in the background, and the indistinguishable speakers.","MISP challenge; speaker diarization; speech recognition; multimodality","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-11-05","","","Multimedia Computing","","",""
"uuid:691514b3-285d-4a75-af82-12d53b3e16ce","http://resolver.tudelft.nl/uuid:691514b3-285d-4a75-af82-12d53b3e16ce","Maverick Matters: Client Contribution and Selection in Federated Learning","Huang, J. (TU Delft Data-Intensive Systems); Hong, C. (TU Delft Data-Intensive Systems); Liu, Yang (Tsinghua University); Chen, Lydia Y. (TU Delft Data-Intensive Systems); Roos, S. (TU Delft Data-Intensive Systems)","Kashima, Hisashi (editor); Ide, Tsuyoshi (editor); Peng, Wen-Chih (editor)","2023","Federated learning (FL) enables collaborative learning between parties, called clients, without sharing the original and potentially sensitive data. To ensure fast convergence in the presence of such heterogeneous clients, it is imperative to timely select clients who can effectively contribute to learning. A realistic but overlooked case of heterogeneous clients are Mavericks, who monopolize the possession of certain data types, e.g., children hospitals possess most of the data on pediatric cardiology. In this paper, we address the importance and tackle the challenges of Mavericks by exploring two types of client selection strategies. First, we show theoretically and through simulations that the common contribution-based approach, Shapley Value, underestimates the contribution of Mavericks and is hence not effective as a measure to select clients. Then, we propose FedEMD, an adaptive strategy with competitive overhead based on the Wasserstein distance, supported by a proven convergence bound. As FedEMD adapts the selection probability such that Mavericks are preferably selected when the model benefits from improvement on rare classes, it consistently ensures the fast convergence in the presence of different types of Mavericks. Compared to existing strategies, including Shapley Value-based ones, FedEMD improves the convergence speed of neural network classifiers with FedAvg aggregation by 26.9% and its performance is consistent across various levels of heterogeneity.","client selection; data heterogeneity; Federated learning; shapley value; wasserstein distance","en","conference paper","Springer","","","","","","","","","","Data-Intensive Systems","","",""
"uuid:c0b4c533-7338-441c-86a5-d005e1fa250a","http://resolver.tudelft.nl/uuid:c0b4c533-7338-441c-86a5-d005e1fa250a","Integrated CO2capture and selective conversion to syngas using transition-metal-free Na/Al2O3dual-function material","Sasayama, Tomone (National Institute of Advanced Industrial Science and Technology (AIST)); Kosaka, Fumihiko (National Institute of Advanced Industrial Science and Technology (AIST)); Liu, Yanyong (National Institute of Advanced Industrial Science and Technology (AIST)); Yamaguchi, Toshiaki (National Institute of Advanced Industrial Science and Technology (AIST)); Chen, Shih Yuan (National Institute of Advanced Industrial Science and Technology (AIST)); Mochizuki, Takehisa (National Institute of Advanced Industrial Science and Technology (AIST)); Urakawa, A. (TU Delft ChemE/Catalysis Engineering); Kuramoto, Koji (National Institute of Advanced Industrial Science and Technology (AIST))","","2022","Integrated CO2 capture and conversion (ICCC) using dual-function materials (DFMs) is one of the key technologies for addressing critical global environmental and energy issues. DFMs generally consist of alkali or alkaline earth metals for CO2 capture and transition metal catalysts for CO2 conversion. In this study, we studied the ICCC to CO using transition-metal-free DFMs to demonstrate their potential to directly produce syngas from atmospheric-level CO2. Among the DFMs prepared herein, Na/Al2O3 exhibited excellent performance and achieved a CO2 conversion exceeding 90% and CO selectivity exceeding 95% at a reaction temperature of 450-500 °C. Na/Al2O3 maintained its capture and conversion capacity throughout a 50-cycle stability test without significant deactivation. Furthermore, in the scale-up experiments using Na/Al2O3 DFM, a syngas-like mixture an H2/CO molar ratio of 3.3 (48.1 vol% H2 and 14.5 vol% CO) was directly obtained from 400 ppm CO2. These results suggest that ICCC using the transition-metal-free Na/Al2O3 DFM may be practicable provided the CO2 capture capacity of the DFM is further improved while maintaining the aforementioned advantages.","COutilization; Dual-function material; Reverse water gas shift; Syngas","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Catalysis Engineering","","",""
"uuid:662aa022-5eb9-43d6-8f70-ae4d52a0310b","http://resolver.tudelft.nl/uuid:662aa022-5eb9-43d6-8f70-ae4d52a0310b","A Contribution to the Development of High-Voltage dc Circuit Breaker Technologies: A Review of New Considerations","Liu, Zhou (Aalborg University); Mirhosseini, S.S. (TU Delft Intelligent Electrical Power Grids); Liu, L. (External organisation); Popov, M. (TU Delft Intelligent Electrical Power Grids; TU Delft Electrical Engineering Education); Ma, Kaiqi (Aalborg University); Hu, Weihao (University of Electronic Science and Technology of China); Jamali, Sadegh (Iran University of Science and Technology); Palensky, P. (TU Delft Intelligent Electrical Power Grids); Chen, Zhe (Aalborg University)","","2022","To promote the integration of renewable energy resources into modern energy systems, high-voltage dc (HVdc) and circuit breaker (CB) technologies have become critical to achieving secure and efficient energy transmission. This article reviews the technical development of the related areas, compares diverse breaker concepts and topologies, investigates possible coordination and testing solutions, and points out the remaining challenges as well as future needs. The time-domain simulation and comparative analysis are adopted in this article to analyze and compare the performances of different HVdc CBs. By making use of different selectivity levels of multiterminal HVdc (MTdc) grids, the suitable planning and placement of HVdc CBs can be conducted. Furthermore, by providing insights into the performance of HVdc CBs, the work presented in this article can serve as a useful asset for the upcoming standardization and industrial application process of HVdc grid and CB design and testing.","Circuit breakers; Fault currents; HVDC transmission; Inductors; Rectifiers; Renewable energy sources; Testing","en","journal article","","","","","","","","","","","Intelligent Electrical Power Grids","","",""
"uuid:31a8a4d3-652f-464d-bda5-d9b5de2e9be2","http://resolver.tudelft.nl/uuid:31a8a4d3-652f-464d-bda5-d9b5de2e9be2","Platform Development of BIM-Based Fire Safety Management System Considering the Construction Site","Yang, Yapin (Hunan University); Sun, Ying (Concordia University); Chen, Mingsi (Hunan University); Zhou, Yuekuan (The Hong Kong Polytechnic University; The Hong Kong University of Science and Technology); Wang, Ran (Hunan University); Liu, Zhengxuan (TU Delft Design & Construction Management; Hunan University)","","2022","Fire at a construction site usually results in serious accidents. Therefore, fire management at the construction site is critical to decreasing possible accidents. However, conventional fire safety management can be problematic in many aspects, such as visualization, multi-stage alarm systems, and dynamic escape route optimization. To solve these issues, this paper develops a platform for a BIM-based fire safety management system that considers the construction site. The developed platform contains four subsystems: a remote monitoring subsystem, a fire visualization subsystem, a multi-stage fire alarm subsystem, and an escape route optimization subsystem. It detects the fire hazard in the early stage of the fire by the remote monitoring subsystem and transmits this information to the fire visualization subsystem for displaying. Furthermore, the multi-stage fire alarm subsystem sends warnings or alarms based on the fire’s severity. Moreover, the escape route optimization subsystem dynamically optimizes the evacuation routes by considering the actual number of people at the construction site and the potential crowding as people pass through the escapeway. Results show that this system can provide informative and on-time fire protection measures to different participants at the construction site. This study can also serve as a solution to improve fire safety management at the construction site.","construction site; fire safety management; BIM technology; escape route optimization; visualization","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:00c0c0b4-78e2-4c89-a351-79cba207f056","http://resolver.tudelft.nl/uuid:00c0c0b4-78e2-4c89-a351-79cba207f056","Review of Laser Sintering of Nanosilver Pastes for Die Attachment: Technologies and Trends","Chen, Haixue (Fudan University); Zhang, Jing (Heraeus Materials Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials); Liu, Pan (Fudan University; Research Institute of Fudan University, Ningbo)","","2022","Nanosilver pastes have been regarded as the most promising die-attach materials for high-temperature and high-power applications due to their advantages such as excellent thermal conductivity, electrical conductivity, high temperature resistance, and good shear strength. However, the common hot pressing sintering process for nanosilver pastes has the limitations of long sintering time and complicated sintering processes. Thus, laser sintering has been proposed as a rapid sintering method that attracts increasing interest due to its advantages of high energy density, fast temperature rise, easy densification, etc. In this review, the recent advances in laser sintering processes were summarized, including pressure laser sintering, backside sintering, and hybrid bimodal laser sintering. The effects of various laser sintering process parameters on joint performance, such as laser power, sintering pressure, irradiation time, and defocusing amount, were further discussed. The rapid sintering mechanism of laser sintering silver nanoparticles(AgNPs) was revealed, while microscopic explanations need to be further explored. This review provided ideas and methods for subsequent researchers to develop rapid sintering methods for power electronic packaging.","Nanosilver; Laser sintering; Die Attachment","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:264690e8-48d0-42da-a02c-63c501ee67f7","http://resolver.tudelft.nl/uuid:264690e8-48d0-42da-a02c-63c501ee67f7","A Hybrid Recursive Implementation of Broad Learning With Incremental Features","Liu, Di (Southeast University); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Yu, Wenwu (Southeast University); Chen, C. L.P. (South China University of Technology)","","2022","The broad learning system (BLS) paradigm has recently emerged as a computationally efficient approach to supervised learning. Its efficiency arises from a learning mechanism based on the method of least-squares. However, the need for storing and inverting large matrices can put the efficiency of such mechanism at risk in big-data scenarios. In this work, we propose a new implementation of BLS in which the need for storing and inverting large matrices is avoided. The distinguishing features of the designed learning mechanism are as follows: 1) the training process can balance between efficient usage of memory and required iterations (hybrid recursive learning) and 2) retraining is avoided when the network is expanded (incremental learning). It is shown that, while the proposed framework is equivalent to the standard BLS in terms of trained network weights,much larger networks than the standard BLS can be smoothly trained by the proposed solution, projecting BLS toward the big-data frontier.","Big data; broad learning system (BLS); recursive learning; training time","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Team Bart De Schutter","","",""
"uuid:5fc63aa1-ad14-4344-8cae-193eac1928a8","http://resolver.tudelft.nl/uuid:5fc63aa1-ad14-4344-8cae-193eac1928a8","Large Region Targets Observation Scheduling by Multiple Satellites Using Resampling Particle Swarm Optimization","Gu, Yi (Beihang University); Han, Chao (Beihang University); Chen, Yuhan (China Satellite Network Innovation Company, Ltd.); Liu, Shenggang (Beihang University); Wang, X. (TU Delft Learning & Autonomous Control; Queen Mary University of London)","","2022","The last decades have witnessed a rapid increase of Earth observation satellites (EOSs), leading to the increasing complexity of EOSs scheduling. On account of the widespread applications of large region observation, this article aims to address the EOSs observation scheduling problem for large region targets. A rapid coverage calculation method employing a projection reference plane and a polygon clipping technique is first developed. We then formulate a nonlinear integer programming model for the scheduling problem, where the objective function is calculated based on the developed coverage calculation method. A greedy initialization-based resampling particle swarm optimization (GI-RPSO) algorithm is proposed to solve the model. The adopted greedy initialization strategy and particle resampling method contribute to generating efficient and effective solutions during the evolution process. In the end, extensive experiments are conducted to illustrate the effectiveness and reliability of the proposed method. Compared to the traditional PSO and the widely used greedy algorithm, the proposed GI-RPSO can improve the scheduling result by 5.42% and 15.86%, respectively.","Large region targets; multiple satellites; observation scheduling; resampling particle swarm optimization (PSO)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-03-12","","","Learning & Autonomous Control","","",""
"uuid:e254f796-cfd1-4c53-a8cb-c716eb4375fa","http://resolver.tudelft.nl/uuid:e254f796-cfd1-4c53-a8cb-c716eb4375fa","Study on vertical vibration and transmission characteristics of railway ballast using impact hammer test","Liu, Ganzhong (Southwest Jiaotong University); Cong, Jianli (Southwest Jiaotong University); Wang, Ping (Southwest Jiaotong University); Du, Shuai (Southwest Jiaotong University); Wang, L. (TU Delft Railway Engineering; Southwest Jiaotong University); Chen, Rong (Southwest Jiaotong University)","","2022","The vertical vibration and transmission characteristics of ballast are key factors that affect the dynamic stability of railway track structures and control the settlement of ballasted beds. Therefore, the following study was conducted to explore this topic. Firstly, through an impact hammer test on a ballast sensor with embedding chip, the vertical vibration data of the ballast was accurately measured. Therefore, the vertical vibration characteristics of a single ballast can be studied. Then, the vertical vibration characteristics at different positions in the stack were obtained by embedding ballast sensors into a ballasted stack. Finally, combined with field tests, a discrete element numerical model was established, then the vibration transmission speed and diffusion angle in a ballasted stack were calculated. The results of this study show that the damping ratio of ballast particles is less than 0.1, and the natural frequency is above 1000 Hz. The damping ratio and natural frequency of ballasts are greatly affected by their shape. The damping ratio of a ballasted stack is greater than that of ballast particles, and its natural frequency is lower. This indicates that the ballasted stack has the attributes of a soft material. The vertical acceleration transmission rate of ballasts is lower at frequencies below 257.94 Hz. This shows that the vibration suppression ability of the ballasted bed is better in the lower frequency range. As the depth increases, the vertical vibration transmission speed of the ballast gradually decreases, as does the accumulated external force. In the impact hammer test of a ballasted box, the average vertical vibration transmission speed was calculated to be 0.88 mm/μs, and the ballast vibration was transmitted downward at a diffusion angle of 35.32°–54.51° from the direction of gravity.","Ballast; Damping; Discrete element; Natural frequency; Transmission; Vibration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-06-04","","","Railway Engineering","","",""
"uuid:a03ab1c9-bc1f-4a62-b1d2-20783b4d60d4","http://resolver.tudelft.nl/uuid:a03ab1c9-bc1f-4a62-b1d2-20783b4d60d4","An online data driven fault diagnosis and thermal runaway early warning for electric vehicle batteries","Sun, S.Z. (TU Delft DC systems, Energy conversion & Storage; Beijing Institute of Technology); Wang, Zhenpo (Beijing Institute of Technology); Liu, Peng (Beijing Institute of Technology); Qin, Z. (TU Delft DC systems, Energy conversion & Storage); Chen, Yong; Han, Yang (The University of Manchester); Wang, Peng (Zhejiang Geely Automobile Research Institute Co); Bauer, P. (TU Delft DC systems, Energy conversion & Storage)","","2022","Battery fault diagnosis is crucial for stable, reliable, and safe operation of electric vehicles, especially the thermal runaway early warning. Developing methods for early failure detection and reducing safety risks from failing high energy lithium-ion batteries has become a major challenge for industry. In this article, a real-time early fault diagnosis scheme for lithium-ion batteries is proposed. By applying both the discrete Fréchet distance and local outlier factor to the voltage and temperature data of the battery cell/module that measured in real time, the battery cell that will have thermal runaway is detected before thermal runaway happens. Compared with the widely used single parameter based diagnosis approach, the proposed one considerably improve the reliability of the fault diagnosis and reduce the false diagnosis rate. The effectiveness of the proposed method is validated with the operational data from electric vehicles with/without thermal runaway in daily use.","Discrete Fréchet distance (DFD); fault diagnosis; lithium-ion battery (LIB); local outlier factor (LOF)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","DC systems, Energy conversion & Storage","","",""
"uuid:f76d5cd9-482f-4e24-bff8-a0ec22e4da31","http://resolver.tudelft.nl/uuid:f76d5cd9-482f-4e24-bff8-a0ec22e4da31","A facile method to prepare oriented boron nitride-based polymer composite with enhanced thermal conductivity and mechanical properties","Chen, Jing (Fudan University; Chinese Academy of Sciences; Southern University of Science and Technology); Liu, X. (TU Delft Electronic Components, Technology and Materials); Zeng, Xiao Liang (Chinese Academy of Sciences); Ye, Huai Yu (Southern University of Science and Technology; Chongqing University); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Fudan University)","","2022","Hexagonal boron nitride (BN) is often used as filler to improve the thermal conductivity of polymer matrix due to its high thermal conductivity. However, previously reported BN-based composites always have a high in-plane thermal conductivity, which is not beneficial for vertical heat dissipation. In addition, high BN content results in the deterioration of the mechanical properties. Here, we report a feasible method to prepare a BN/silicone rubber (SiR) composite with oriented BN in organosilicon matrix via a vacuum-assisted self-assembly technique. The BN/SiR composite displays a 1270% higher (2.74 W/(m·K)) thermal conductivity than that of neat organosilicon matrix (0.20 W/(m·K)). The oriented BN nanosheets increase the polymer's adhesive force and exhibit excellent compression cycle performance. In turn, these features support its superiority as thermal interface material in the light-emitting diode chips heat dissipation application.","Boron nitride; Mechanical property; Polymer composites; Thermal conductivity; Vacuum-assisted self-assembly method","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Electronic Components, Technology and Materials","","",""
"uuid:7a9849c6-522c-4922-a0ba-f5ca7214f69c","http://resolver.tudelft.nl/uuid:7a9849c6-522c-4922-a0ba-f5ca7214f69c","Supplementary control based on current source coupling for improving dynamic characteristics of active distribution network","Hou, Jue (Huazhong University of Science and Technology); Liu, Zhou (Aalborg University); Wang, Shaorong (Huazhong University of Science and Technology); Chen, Zhe (Aalborg University); Xie, Wei (The State Grid Shanghai Municipal Electric Power Company); Fang, Cheng (The State Grid Shanghai Municipal Electric Power Company); Wei, Xinchi (The State Grid Shanghai Municipal Electric Power Company); Popov, M. (TU Delft Intelligent Electrical Power Grids)","","2022","Supplementary control (SC) technology is widely leveraged by power supply companies in active distribution networks (ADNs) to improve their stability and dynamic characteristics. Yet, the existed SCs are generally implemented from inside the converter controllers of distributed generators (DGs) or active loads, so there is a need to redesign the internal physical structure of the existing controller, resulting in the increasing work amount of assembling and workability. This paper studies the specific R & D process of a novel external coupling type SC (ECSC), which is based upon current source injection (CSI-ECSC) for improving the dynamic characteristics of ADN. The SC current signals are coupled to the current sampling loop from outside the converter controller. And the employment of the existing current sample makes it unnecessary to redesign the internal physical structure of the existing controller. As a result, the SC assembling is simplified and its workability is improved. In this paper, a detailed exemplary ADN with direct-drive permanent magnet synchronous generator (PMSG) is firstly set up in math for full eigenvalue analysis. Then, the CSI-ECSC is designed with its control loop, interface circuit, and parameter setting. Furthermore, by using PSCAD/EMTDC, groups of case studies are conducted in ADNs where photovoltaics (PVs) and energy storage (ES) are included. Finally, the real-time hardware-in-the-loop (HIL) testing validates the functionality of the realized CSI-ECSC in RTDS.","Active distribution network; Converter controller; Eigenvalue analysis; Hardware in the loop; RTDS; Supplementary control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-03-03","","","Intelligent Electrical Power Grids","","",""
"uuid:b051afbc-2c6a-4270-be2e-513f0cb14991","http://resolver.tudelft.nl/uuid:b051afbc-2c6a-4270-be2e-513f0cb14991","Dynamic wind turbine wake reconstruction: A Koopman-linear flow estimator","Chen, Z. (TU Delft Team Jan-Willem van Wingerden; North China Electric Power University); Lin, Zhongwei (North China Electric Power University); Zhai, Xiaoya (University of Science and Technology of China); Liu, Jizhen (North China Electric Power University)","","2022","A challenging topic arising in dynamic wind turbine wake is modeling, especially the low-order approximation. The central problem is the fact that it has high-dimensional and nonlinear wake characteristics. In this paper, a Koopman-linear flow estimator is designed according to the Koopman operator theory. Different from the conventional flow reconstruction with the linear stochastic estimation method, a dynamic state-space model with physical states is constructed. The wake dynamics are approximated using a limited number of measurable physical parameters by the dynamic part; then, the full wake flow is reconstructed from the low-order states by the estimation part. The flow estimator is designed into three different forms following Extended Dynamic Mode Decomposition (EDMD) method. Each form has its unique advantages. Precisely, probe sensors are placed in the studied space and provide direct information of the wake, and a few in-directly physical parameters are also included. Nonlinear integer programming is further adopted using a heuristic optimization algorithm, by which the sensor configurations are optimized. Comparisons with the standard Dynamic Mode Decomposition (DMD)-based wake model are adopted in time domain and frequency domain to verify the effectiveness of the proposed flow estimators. The results show acceptable accuracy in typical modeling cases and maintain good estimation accuracy when the measurement noises are involved. Finally, the proposed Koopman-linear flow estimator is compared with related stochastic estimation methods, in which the connections of the proposed estimator with stochastic ones are also discussed.","Extended dynamic mode decomposition; Flow reconstruction; Koopman operator; Wake effect; Wind turbine","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Team Jan-Willem van Wingerden","","",""
"uuid:0817df44-5800-4f89-ad86-8b1a9b72b419","http://resolver.tudelft.nl/uuid:0817df44-5800-4f89-ad86-8b1a9b72b419","A Series of Ternary Metal Chloride Superionic Conductors for High-Performance All-Solid-State Lithium Batteries","Liang, Jianwen (University of Western Ontario); van der Maas, E.L. (TU Delft RST/Storage of Electrochemical Energy); Luo, Jing (University of Western Ontario); Li, Xiaona (University of Western Ontario); Chen, Ning (TU Delft Photovoltaic Materials and Devices; Canadian Ligth Source, Saskatoon); Adair, Keegan R. (University of Western Ontario); Li, Weihan (University of Western Ontario); Li, Junjie (University of Western Ontario); Hu, Yongfeng; Liu, Jue (Oak Ridge National Laboratory); Zhang, Li; Zhao, W. (TU Delft RST/Storage of Electrochemical Energy); Parnell, S.R. (TU Delft RID/TS/Instrumenten groep); Ganapathy, S. (TU Delft RID/TS/Instrumenten groep); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy)","","2022","Understanding the relationship between structure, ionic conductivity, and synthesis is the key to the development of superionic conductors. Here, a series of Li3-3xM1+xCl6 (−0.14 < x ≤ 0.5, M = Tb, Dy, Ho, Y, Er, Tm) solid electrolytes with orthorhombic and trigonal structures are reported. The orthorhombic phase of Li–M–Cl shows an approximately one order of magnitude increase in ionic conductivities when compared to their trigonal phase. Using the Li–Ho–Cl components as an example, their structures, phase transition, ionic conductivity, and electrochemical stability are studied. Molecular dynamics simulations reveal the facile diffusion in the z-direction in the orthorhombic structure, rationalizing the improved ionic conductivities. All-solid-state batteries of NMC811/Li2.73Ho1.09Cl6/In demonstrate excellent electrochemical performance at both 25 and −10 °C. As relevant to the vast number of isostructural halide electrolytes, the present structure control strategy guides the design of halide superionic conductors.","all-solid-state Li batteries; energy storage; halides; solid-state electrolytes; superionic conductors","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","RST/Storage of Electrochemical Energy","","",""
"uuid:2a20368f-c8a6-4839-8cd1-0b87a7ce6c65","http://resolver.tudelft.nl/uuid:2a20368f-c8a6-4839-8cd1-0b87a7ce6c65","A two-dimensional ordinary state-based peridynamic model for surface fatigue crack propagation in railheads","Ma, Xiaochuan (East China Jiaotong University); Wang, L. (TU Delft Railway Engineering); Xu, Jinhui (East China Jiaotong University); Feng, Qingsong (East China Jiaotong University); Liu, Linya (East China Jiaotong University); Chen, Huapeng (East China Jiaotong University)","","2022","Based on ordinary state-based peridynamic theory, a 2D peridynamic model has been established to investigate fatigue crack propagation in railheads. The proposed model is verified in terms of rail deformation under a quasi-static load and the ductile material-related fatigue failure model. Good agreements have been achieved between a finite element model and the experimental results. With the proposed model, the effects of the initial crack angle, initial crack length and wheel-rail friction coefficient on crack propagation in railheads are studied. This research provides a new method for studying crack propagation in railheads.","Crack propagation; Fatigue; Peridynamic model; Railway; Wheel-rail contact","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-08-28","","","Railway Engineering","","",""
"uuid:095cb1cf-424d-41e1-809b-0006454cc24c","http://resolver.tudelft.nl/uuid:095cb1cf-424d-41e1-809b-0006454cc24c","Undrained stability of pit-in-pit braced excavations under hydraulic uplift","Lai, F. (TU Delft Geo-engineering; Southeast University); Chen, Fuquan (Fuzhou University); Liu, Songyu (Southeast University); Keawsawasvong, Suraparb (Thammasat University); Shiau, Jim (University of Southern Queensland)","","2022","Pit-in-pit (PIP) excavations in an aquifer–aquitard system likely undergo catastrophic failures under the hydraulic uplift, the associated undrained stability problem, however, has not been well analyzed in the past. To this end, a hypothetical model of PIP braced excavation in typical soil layers of Shanghai, China is developed using the finite element limit analysis (FELA) tool. The FELA solutions of safety factors (FSs) against hydraulic uplift are verified with the results from the finite element analysis with strength reduction technique (SRFEA) and existing design approaches. Subsequently, FELA is employed to identify the triggering and failure mechanisms of PIP braced excavations subjected to hydraulic uplift. A series of parametric studies considering the various geometric configurations of the PIP excavation, undrained shear strengths of aquitard, and artesian pressures are carried out. The sensitivities of relevant design parameters are further assessed using a multivariate adaptive regression splines (MARS) model that is capable of accurately capturing the nonlinear relationships between a set of input variables and output variables in multi-dimensions. A MARS-based design equation used for predicting FS is finally presented using the artificial dataset from FELA for practical design uses.","Finite element limit analysis; Hydraulic uplift; Multivariate adaptive regression splines; Pit-in-pit excavation; Undrained stability","en","journal article","","","","","","","","","","","Geo-engineering","","",""
"uuid:1977ade0-f41e-4c8f-a22c-b77f96a94d55","http://resolver.tudelft.nl/uuid:1977ade0-f41e-4c8f-a22c-b77f96a94d55","Research on Design and Performance of Self-Compacting Cement Emulsified Bitumen Mixture (CEBM)","Yi, Jinming (Wuhan Institute of Technology; Poly Changda Overseas Engineering Co.); Feng, Jianlin (Wuhan Institute of Technology); Li, Yuanyuan (Wuhan Institute of Technology); Bai, Tao (Wuhan Institute of Technology); Chen, Anqi (Wuhan University of Technology); Gao, Y. (TU Delft Pavement Engineering); Wu, Fan (Wuhan Institute of Technology); Wu, Shaopeng (Wuhan University of Technology); Liu, Quantao (Wuhan University of Technology); Li, Chuangmin (Changsha University of Science and Technology)","","2022","To meet the needs of the road industry for maintenance operations, a new cement emulsified bitumen mixture (CEBM) with early-strength, self-compacting, and room-temperature construction characteristics was designed. The strength formation mechanism of CEBM was revealed with a scanning electron microscope (SEM) and the surface free energy (SFE) theory. The mechanical properties and road performance of the CEBM were investigated extensively. The results show that before the demulsification of emulsified bitumen, the SFE of the bitumen–aggregate–water three-phase system was reduced due to the replacement of the bitumen–aggregate interface with water. The adhesion work between the emulsified bitumen and the aggregate is negative, which means the adhesion between the emulsified bitumen and the aggregate will not occur spontaneously due to the existence of water. The liquid emulsified bitumen improves the workability of the mixture and ensures that the mixture can be evenly mixed and self-compacted. After demulsification, the work of adhesion between the residual bitumen and the aggregate is positive, which means residual bitumen and aggregate can bond spontaneously. In addition, the hydration products of cement and aggregate form a skeleton, and the emulsified bitumen film wraps and bonds the cement and aggregate together, creating strength. The emulsified bitumen, cement content, and curing conditions have significant effects on the stability of CEBM. The recommended dosage of emulsified bitumen and cement is 8% and 8–10%, respectively. This material integrates the hardening effect of cement and the viscoelastic performance of bitumen and has good workability, mechanical properties, and road performance. Therefore, the CEBM is technically feasible for application to bitumen pavement.","bitumen/cement composite mixture; early-strength; mixture performance; self-compacted; strength formation mechanism","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:69e57fff-6f7e-40e2-abd9-13e50c76657b","http://resolver.tudelft.nl/uuid:69e57fff-6f7e-40e2-abd9-13e50c76657b","Direct and continuous conversion of flue gas CO2 into green fuels using dual function materials in a circulating fluidized bed system","Kosaka, Fumihiko (National Institute of Advanced Industrial Science and Technology (AIST)); Sasayama, Tomone (National Institute of Advanced Industrial Science and Technology (AIST)); Liu, Yanyong (National Institute of Advanced Industrial Science and Technology (AIST)); Chen, S. (National Institute of Advanced Industrial Science and Technology (AIST)); Mochizuki, Takehisa (National Institute of Advanced Industrial Science and Technology (AIST)); Matsuoka, Koichi (National Institute of Advanced Industrial Science and Technology (AIST)); Urakawa, A. (TU Delft ChemE/Catalysis Engineering); Kuramoto, Koji (National Institute of Advanced Industrial Science and Technology (AIST))","","2022","Carbon capture and utilization (CCU) technologies, such as CO2 methanation, generally require energy-intensive CO2 capture and separation processes prior to catalytic CO2 conversion. In contrast, integrated CO2 capture and reduction (CCR) technologies that use dual function materials (DFM) can directly convert low-concentration CO2 in flue gas or atmosphere into high-concentration CH4 or CO. In this study, we demonstrate a circulating fluidized bed (CFB) approach to enable continuous operation of CCR. In the CFB approach, the DFM (Na/Ni/Al2O3) circulates between two bubbling fluidized beds to enable steady-state cyclic operation of (1) selective capture of CO2 in flue gas/air and (2) hydrogenation of the captured CO2. We succeeded in the continuous synthesis of CH4 with high CO2 capture efficiency (>88 %) and high H2 conversion (>85 %) yielding mainly CH4 (selectivity > 99 %) as the product at high concentration (>20 % CH4) using 2 % CO2/N2 as the model flue gas.","CO capture; CO hydrogenation; CO utilization; Dual function material; Fluidized bed; Methanation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","ChemE/Catalysis Engineering","","",""
"uuid:c650e123-84b2-4607-8403-e0c7c1cbfaea","http://resolver.tudelft.nl/uuid:c650e123-84b2-4607-8403-e0c7c1cbfaea","Lightweight and Accurate DNN-Based Anomaly Detection at Edge","Zhang, Qinglong (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Xin, Gaofeng (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2022","Deep neural networks (DNNs) have been showing significant success in various anomaly detection applications such as smart surveillance and industrial quality control. It is increasingly important to detect anomalies directly on edge devices, because of high responsiveness requirements and tight latency constraints. The accuracy of DNN-based solutions rely on large model capacity and thus long training and inference time, making them inapplicable on resource strenuous edge devices. It is hence imperative to scale DNN model sizes in correspondence to the run-time system requirements, i.e., meeting deadlines with minimal accuracy losses, which are highly dependent on the platforms and real-time system status. Existing scaling techniques either take long training time to pre-generate scaling options or disturb the unsteady training process of anomaly detection DNNs, lacking the adaptability to heterogeneous edge systems and incurring low inference accuracies. In this article, we present LightDNN to scale DNN models for anomaly detection applications at edge, featuring high detection accuracies with lightweight training and inference time. To this end, LightDNN quickly extracts and compresses blocks in a DNN, and provides large scaling space (e.g., 1 million options) by dynamically combining these compressed blocks online. At run-time, LightDNN predicts the DNN's inference latency according to the monitored system status, and optimizes the combination of blocks to maximize its accuracy under deadline constraints. We implement and extensively evaluate LightDNN on both CPU and GPU edge platforms using 8 popular anomaly detection workloads. Comparative experiments with state-of-the-art methods show that our approach provides 145.8 to 0.56 trillion times more scaling options without increasing training and inference overheads, thus achieving as much as 15.05% increase in accuracy under the same deadlines.","Anomaly detection; DNN; edge inference; model scaling; predictable latency","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:9864c313-2e8a-4521-a624-dc956ef615fd","http://resolver.tudelft.nl/uuid:9864c313-2e8a-4521-a624-dc956ef615fd","EdgeTuner: Fast Scheduling Algorithm Tuning for Dynamic Edge-Cloud Workloads and Resources","Han, Rui (Beijing Institute of Technology); Wen, Shilin (Beijing Institute of Technology); Liu, Chi Harold; Yuan, Ye (Beijing Institute of Technology); Wang, Guoren (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems)","","2022","Edge-cloud jobs are rapidly prevailing in many application domains, posing the challenge of using both resource-strenuous edge devices and elastic cloud resources. Efficient resource allocation on such jobs via scheduling algorithms is essential to guarantee their performance, e.g. latency. Deep reinforcement learning (DRL) is increasingly adopted to make scheduling decisions but faces the conundrum of achieving high rewards at a low training overhead. It is unknown if such a DRL can be applied to timely tune the scheduling algorithms that are adopted in response to fast changing workloads and resources. In this paper, we propose EdgeTuner to effectively leverage DRL to select scheduling algorithms online for edge-cloud jobs. The enabling features of EdgeTuner are sophisticated DRL model that captures complex dynamics of Edge-Cloud jobs/tasks and an effective simulator to emulate the response times of short-running jobs in accordance to dynamically changing scheduling algorithms. EdgeTuner trains DRL agents offline by directly interacting with the simulator. We implement EdgeTuner on Kubernetes scheduler and extensively evaluate it on Kubernetes cluster testbed driven by the production traces. Our results show that EdgeTuner outperforms prevailing scheduling algorithms by achieving significant lower job response time while accelerating DRL training speed by more than 180x.","DRL; Edge-cloud workloads; Kubernetes; run-time tuning; scheduling algorithm","en","conference paper","Institute of Electrical and Electronics Engineers (IEEE)","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:3903b9a3-f858-481d-abfb-68c427e577a8","http://resolver.tudelft.nl/uuid:3903b9a3-f858-481d-abfb-68c427e577a8","Capturing and tracing the spatiotemporal variations of planktonic and particle-associated bacteria in an unchlorinated drinking water distribution system","Chen, L. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Li, Xuan (Student TU Delft); van der Meer, Walter (University of Twente; Oasen); Medema, G.J. (TU Delft Sanitary Engineering; KWR Water Research Institute; Michigan State University); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences)","","2022","The aperiodic changes in the quantity and community of planktonic and particle-associated bacteria have hampered the understanding and management of microbiological water quality in drinking water distribution systems. In this study, online sampling was combined with the microbial fingerprint-based SourceTracker2 to capture and trace the spatiotemporal variations in planktonic and particle-associated bacteria in an unchlorinated distribution system. The results showed that spatially, the particle load significantly increased, while in contrast, the quantity of particle-associated bacteria decreased sharply from the treatment plant to the distribution network. Similar to the trend of particle-associated bacterial diversity, the number of observed OTUs first slightly decreased from the treatment plant to the transportation network and then sharply increased from the transportation network to the distribution network. The SourceTracker2 results revealed that the contribution of particle-associated bacteria from the treatment plant decreased along the distribution distance. The spatial results indicate the dominant role of sedimentation of particles from the treatment plant, while the observed increases in particles and the associated bacteria mainly originated from the distribution network, which were confirmed directly by the increased contributions of loose deposits and biofilm. Temporally, the daily peaks of particle-associated bacterial quantity, observed OTU number, and contributions of loose deposits and biofilms were captured during water demand peaks (e.g., 18–21 h). The temporal results reveal clear linkages between the distribution system harboring bacteria (e.g., within loose deposits and biofilms) and the planktonic and particle-associated bacteria flowing through the distribution system, which are dynamically connected and interact. This study highlights that the spatiotemporal variations in planktonic and particle-associated bacteria are valuable and unneglectable for the widely on-going sampling campaigns required by water quality regulations and/or drinking water microbiological studies.","Drinking water distribution system (DWDS); Online monitoring sampling system (OMSS); Planktonic and particle-associated bacteria; SourceTracker2; Spatiotemporal variations","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:10b85d45-d3dd-4ec1-b9d2-3f4d37663c7a","http://resolver.tudelft.nl/uuid:10b85d45-d3dd-4ec1-b9d2-3f4d37663c7a","O3HSC: Outsourced Online/Offline Hybrid Signcryption for Wireless Body Area Networks","Liu, Suhui (Southeast University); Chen, Liquan (Southeast University); Wang, Huaqun (Nanjing University of Posts and Telecommunications); Fu, S. (TU Delft Cyber Security); Shi, Lin (Southeast University)","","2022","Wireless body area networks (WBAN) enable ubiquitous monitoring of patients, which can change the future of healthcare services overwhelmingly. As the collected data of patients usually contain sensitive information, how to collect, transfer, store and share data securely and properly has become a concerning issue. Attribute-based encryption (ABE) can achieve data confidentiality and fine-grained access control simultaneously. Identity-based ring signature (IBRS) allows patients to prove their identity without leaking any extra (private) information. However, the heavy computational burden of ABE and IBRS is intolerable for most power-limited mobile devices, which account for a large proportion of WBAN devices. This paper combines the attribute-based online/offline encryption (ABOOE) and IBRS to achieve an outsourced online/offline hybrid signcryption ( O3 HSC) scheme. As far as we know, this scheme is the first signcryption scheme that adopts IBRS and satisfies online/offline signcryption simultaneously. O3 HSC divides the key generation and signcryption into offline and online phases to increase the throughput of the central authority and save the power resources of mobile devices, respectively. Besides, outsourced decryption and public signature verification are also realized. O3 HSC achieves security under CCA and CMIA, and the performance analysis shows that O3 HSC is a lightweight and applicable scheme for WBAN.","Attribute-based online/offline encryption; identity-based ring signature; outsourced decryption; wireless body area network","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Cyber Security","","",""
"uuid:e7a619bb-33ab-4295-8239-889fbf1880ca","http://resolver.tudelft.nl/uuid:e7a619bb-33ab-4295-8239-889fbf1880ca","Numerical analyses of energy balance and installation mechanisms of large-diameter tapered monopiles by impact driving","Chen, Fuquan (Fuzhou University); Liu, Liyang (Fuzhou University); Lai, F. (TU Delft Geo-engineering; Southeast University); Gavin, Kenneth (TU Delft Geo-engineering); Flynn, Kevin N. (Brazil Piling & Foundations); Li, Yida (Fuzhou University)","","2022","Large-diameter monopiles are widely used as the foundation to support offshore wind turbines (OWTs) in shallow coastal waters. The benefits of small-to-medium diameter tapered piles have been reported in the past. The potential use of large-diameter tapered monopiles installed by impact driving to support OWTs is thus presented, and then comparatively assessed by numerical analyses in terms of energy balance and installation mechanisms. A three-dimensional large deformation finite element (3D-LDFE) model of monopiles driven in clay was developed using a Coupled Eulerian-Lagrangian (CEL) approach. An advanced user-defined hypoplasticity clay (HC) model was employed to model undrained kaolin clay, featuring nonlinear behavior from small strain to large strain. The force-time curve defined by the operating data of a state-of-the-art hammer in the offshore industry was inputted to explicitly model impact driving. Better agreement between the measured and the simulated results was observed to validate the accuracy of the numerical model. The numerical results obtained give greater confidence to the future use of large diameter tapered monopiles for OWTs.","Drivability performance; Energy balance; Finite-element modeling; Impact driving; Installation mechanism; Offshore wind turbines; Piles & piling","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-05-09","","","Geo-engineering","","",""
"uuid:5c3e052f-9f99-4052-8e77-e01b42b4f1a7","http://resolver.tudelft.nl/uuid:5c3e052f-9f99-4052-8e77-e01b42b4f1a7","Mapping the knowledge domain of soft computing applications for emergency evacuation studies: A scientometric analysis and critical review","Liang, Benbu (TU Delft System Engineering; TU Delft Multi Actor Systems; Wuhan University of Technology); van der Wal, C.N. (TU Delft Multi Actor Systems; TU Delft System Engineering); Xie, Kefan (Wuhan University of Technology); Chen, Y. (TU Delft Materials and Environment; Wuhan University of Technology); Brazier, F.M. (TU Delft Multi Actor Systems; TU Delft System Engineering); Dulebenets, Maxim A. (Florida State University); Liu, Zimei (Huazhong Agricultural University)","","2022","Emergency evacuation is viewed as a common strategy adopted during the disaster preparedness stage of evacuation to ensure the safety of potentially affected populations. In emergency evacuation studies, soft computing approaches and methodologies have been widely used to support effective decision-making, providing robust and low-cost solutions. To understand the current status and trends of research on soft computing applications for emergency evacuation studies, 778 related studies published in the core database of Web of Science from 2000 to 2020 were considered in this study. A scientometric analysis and a comprehensive review were performed using a scientific mapping of the knowledge domain. This paper presents a set of analyses with the following primary objectives: (1) to explore and visualize the bibliometric characteristics and contents of the academic field concerned with the soft computing approaches for emergency evacuation; and (2) to review and analyze the knowledge, hotspots, and future outlooks related to soft computing approaches for emergency evacuation. The results provide some important insights regarding the existing soft computing methods that have been used in the emergency evacuation field over the past 20 years. Based on the conducted review, this paper proposes that future studies should concentrate on exploring the potential of innovative soft computing approaches for crowd modelling and enabling more accurate evacuation simulation and optimization.","Disaster management; Emergency evacuation; Knowledge domain; Scientometric analysis; Soft computing","en","review","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-04-15","","Multi Actor Systems","System Engineering","","",""
"uuid:493ca68f-c62d-49b8-940c-80e7aa6a8885","http://resolver.tudelft.nl/uuid:493ca68f-c62d-49b8-940c-80e7aa6a8885","Influence of coarse aggregate settlement induced by vibration on long-term chloride transport in concrete: a numerical study","Cai, Yuxin (Shanghai Jiao Tong University; Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure); Liu, Qing feng (Shanghai Jiao Tong University; Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure); Meng, Zhaozheng (Shanghai Jiao Tong University; Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure); Chen, Mengzhu (Sun Yat-sen University); Li, Weihua (Sun Yat-sen University); Šavija, B. (TU Delft Materials and Environment)","","2022","High-frequency vibration helps to improve the compactness of concrete, but also causes the settlement of coarse aggregates (CAs) and then affects the durability of hardened concrete. In this paper, a numerical study combining multi-phase CA settlement model and multi-component ionic transport model is performed to understand the influence of vibration-induced settlement on long-term chloride transport in concrete. Through parametric analysis, the influence mechanism of relevant factors on both chloride profile distribution and reinforcement corrosion initiation is discussed in detail. The results indicate that with the increase of vibration time, a decrease of chloride concentration appears in the bottom part of concrete specimen and a significant increase in the top part, because more CAs deposit in the bottom layer. Due to sedimentation, a more obvious fluctuation of chloride concentration along the height direction can be observed in the concrete mixed with a larger density and particle size of CAs. According to the model prediction, the corrosion of the top steel bar initiates 1.03–1.80 years earlier than that of the bottom steel bar under the same parameters. In practical engineering, special attention should be paid on the stability of fresh concrete and vibrating procedures to avoid obvious CA settlement.","CA settlement; Chloride transport; Corrosion initiation; Durability; Numerical model; Vibration","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Materials and Environment","","",""
"uuid:488cad9d-badf-4818-8cb2-1b28d5d44c01","http://resolver.tudelft.nl/uuid:488cad9d-badf-4818-8cb2-1b28d5d44c01","The First Multimodal Information Based Speech Processing (Misp) Challenge: Data, Tasks, Baselines And Results","Chen, Hang (University of Science and Technology of China); Zhou, Hengshun (University of Science and Technology of China); Du, Jun (University of Science and Technology of China); Lee, Chin-Hui (Georgia Institute of Technology); Chen, Jingdong (Northwestern Polytechnical University); Watanabe, Shinji (Carnegie Mellon University); Siniscalchi, Sabato Marco (Georgia Institute of Technology; University of Enna Kore); Scharenborg, O.E. (TU Delft Multimedia Computing); Liu, Di-Yuan (iFlytek)","","2022","In this paper we discuss the rational of the Multi-model Information based Speech Processing (MISP) Challenge, and provide a detailed description of the data recorded, the two evaluation tasks and the corresponding baselines, followed by a summary of submitted systems and evaluation results. The MISP Challenge aims at tack-ling speech processing tasks in different scenarios by introducing information about an additional modality (e.g., video, or text), which will hopefully lead to better environmental and speaker robustness in realistic applications. In the first MISP challenge, two bench-mark datasets recorded in a real-home TV room with two reproducible open-source baseline systems have been released to promote research in audio-visual wake word spotting (AVWWS) and audio-visual speech recognition (AVSR). To our knowledge, MISP is the first open evaluation challenge to tackle real-world issues of AVWWS and AVSR in the home TV scenario.","MISP challenge; microphone array; audio-visual; automatic speech recognition; wake word spotting","en","conference paper","IEEE","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Multimedia Computing","","",""
"uuid:828dd13b-2d57-4e96-b770-41b4b5c715ea","http://resolver.tudelft.nl/uuid:828dd13b-2d57-4e96-b770-41b4b5c715ea","Federated Learning With Heterogeneity-Aware Probabilistic Synchronous Parallel on Edge","Zhao, Jianxin (Beijing Institute of Technology); Han, Rui (Beijing Institute of Technology); Yang, Yongkai (Beijing Engineering Research Center of Civil Aviation Big Data; Key Laboratory of Intelligent Passenger Service of Civil Aviation-CAAC); Catterall, Benjamin (University of Cambridge); Liu, Chi Harold (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Data-Intensive Systems); Mortier, Richard (University of Cambridge); Crowcroft, Jon (University of Cambridge); Wang, Liang (University of Cambridge)","","2022","With the massive amount of data generated from mobile devices and the increase of computing power of edge devices, the paradigm of Federated Learning has attracted great momentum. In federated learning, distributed and heterogeneous nodes collaborate to learn model parameters. However, while providing benefits such as privacy by design and reduced latency, the heterogeneous network present challenges to the synchronisation methods, or barrier control methods, used in training, regarding system progress and model convergence etc. The design of these barrier mechanisms is critical for the performance and scalability of federated learning systems. We propose a new barrier control technique called Probabilistic Synchronous Parallel (PSP). In contrast to existing mechanisms, it introduces a sampling primitive that composes with existing barrier control mechanisms to produce a family of mechanisms with improved convergence speed and scalability. Our proposal is supported with a convergence analysis of PSP-based SGD algorithm. In practice, we also propose heuristic techniques that further improve the efficiency of PSP. We evaluate the performance of proposed methods using the federated learning specific FEMNSIT dataset. The evaluation results show that PSP can effectively achieve good balance between system efficiency and model accuracy, mitigating the challenge of heterogeneity in federated learning.","Federated learning; edge computing; distributed computing; barrier control","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-07-01","","","Data-Intensive Systems","","",""
"uuid:2496cbf2-0b8a-43cf-9cc4-251c0d968f57","http://resolver.tudelft.nl/uuid:2496cbf2-0b8a-43cf-9cc4-251c0d968f57","Erratum: Plane-wave orthogonal polynomial transform for amplitude-preserving noise attenuation (Geophysical Journal International (2018) 214 (ggy267) DOI: 10.1093/gji/ggy267)","Chen, Yangkang (Zhejiang University); Huang, Weilin (China University of Petroleum - Beijing); Zhou, Yatong (Hebei University of Technology); Liu, Wei (China University of Petroleum - Beijing); Zhang, D. (TU Delft ImPhys/Medical Imaging; TU Delft ImPhys/Computational Imaging)","","2021","The journal is publishing this Expression of Concern to alert readers while we investigate to determine whether further action is required.","","en","journal article","","","","","","","","","","","ImPhys/Medical Imaging","","",""
"uuid:45361cb1-0faa-4393-9699-839e83e7ce73","http://resolver.tudelft.nl/uuid:45361cb1-0faa-4393-9699-839e83e7ce73","Fostering Ambidextrous Innovation Strategies in Large Infrastructure Projects: A Team Heterogeneity Perspective","Zhang, Xinyue (Tongji University); Le, Yun (Tongji University); Liu, Y. (TU Delft Integral Design & Management); Chen, Xiaoyan (Tongji University)","","2021","In emerging economies, infrastructure projects are in full swing. There is a wealth of replicable experience for exploitation. Simultaneously, more technologies and methodologies require further exploration. This makes fostering ambidextrous innovation strategies (i.e., the tradeoff between exploitative and exploratory innovation strategies) a common and vital practical issue. Large infrastructure projects are unique one-off endeavors but have somewhat repetitive and persistent characteristics. It is a particular “intermediate” form between temporary projects and permanent organizations. Previous research on fostering ambidextrous innovation strategies cannot simply be replicated in large infrastructure projects. To address this issue, this article investigates the relationship between team heterogeneity and ambidextrous innovation strategies and also the role of team learning and identification in large infrastructure projects. Data were collected from 269 responses from 31 large infrastructure project delivery teams in China. The findings show that team heterogeneity has a positive linear effect on exploratory and ambidextrous innovation strategies and an inverted U-shaped effect on exploitative innovation strategies; team heterogeneity can better foster ambidextrous innovation strategies through improving team learning; the moderating role of team identification in the overall mechanism differs from the usual assumptions in permanent organizations. Overall, this article extends the existing ambidexterity research in the “intermediate” form between temporary projects and permanent organizations. It provides insights and guidance on fostering ambidextrous innovation strategies in large infrastructure projects.","Ambidextrous innovation strategies; Education; Focusing; large infrastructure project; Merging; Meteorology; Organizations; Task analysis; team heterogeneity; team identification; team learning; Technological innovation","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:d717f418-0a4d-492f-bf79-5902214c967a","http://resolver.tudelft.nl/uuid:d717f418-0a4d-492f-bf79-5902214c967a","Numerical investigation of external sulfate attack and its effect on chloride binding and diffusion in concrete","Zhang, Cheng-lin (Shanghai Jiao Tong University); Chen, Wei-kang (Shanghai Jiao Tong University); Mu, Song (Jiangsu Research Institute of Building Science,); Šavija, B. (TU Delft Materials and Environment); Liu, Qing-feng (Shanghai Jiao Tong University; Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure)","","2021","Reinforced concrete (RC) structures may suffer from serious durability problems during long-term service. To investigate the deterioration of RC structures subjected to the dual attacks of chlorides and sulfates, this study proposes a coupled model for external sulfate attack (ESA) and its effect on chloride binding and diffusion. To account for the influence of sulfate attack on chloride binding, a reduction function is proposed. The effect of sulfate-induced damage on the chloride diffusion and chloride binding is considered through a damage function. The coupled model is validated against third-party experimental data from multiple perspectives. Some important factors such as solution concentration, immersion time, curing time and water-cement ratio, as well as how these factors affect the impact of sulfate attack on chloride transport, were elaborated. The findings may bring insights to the durability design of RC structures serving in harsh environments.","Binding capacity; Chloride diffusivity; Damage evolution; External sulfate attack; Multi-phase","en","journal article","","","","","","Accepted author manuscript","","2023-03-11","","","Materials and Environment","","",""
"uuid:8a5b73b4-de02-4b99-95e7-424b83e4e7c7","http://resolver.tudelft.nl/uuid:8a5b73b4-de02-4b99-95e7-424b83e4e7c7","Enhanced Activity of Integrated CO2Capture and Reduction to CH4under Pressurized Conditions toward Atmospheric CO2Utilization","Kosaka, Fumihiko (National Institute of Advanced Industrial Science and Technology (AIST)); Liu, Yanyong (National Institute of Advanced Industrial Science and Technology (AIST)); Chen, Shih Yuan (National Institute of Advanced Industrial Science and Technology (AIST)); Mochizuki, Takehisa (National Institute of Advanced Industrial Science and Technology (AIST)); Takagi, Hideyuki (National Institute of Advanced Industrial Science and Technology (AIST)); Urakawa, A. (TU Delft ChemE/Catalysis Engineering); Kuramoto, Koji (National Institute of Advanced Industrial Science and Technology (AIST))","","2021","A desirable process for realizing a low-carbon society is the direct conversion of dilute CO2 from flue gases or air into highly concentrated hydrocarbons without a need for separate CO2 capture and purification processes. In this study, we investigated the performance of integrated CO2 capture and reduction to CH4 over Ni-based dual-functional catalysts promoted with Na, K, and Ca. Ni/Na-γ-Al2O3 exhibited the highest activity for integrated CO2 (5% CO2) capture and reduction, achieving high CO2 conversion (>96%) and CH4 selectivity (>93%). In addition, very low-concentration CO2 (100 ppm CO2) was successfully converted to 11.5% CH4 at the peak point (>1000 times higher concentration than that of the supplied CO2) over Ni/Na-γ-Al2O3. The Ni-based dual-functional catalyst exhibited a high CO2 conversion exceeding 90%, even when 20% O2 was present during CO2 capture. Furthermore, an increased operation pressure had positive impacts on both CO2 capture and CH4 formation, and these advantageous effects were also observed when CO2 concentration was at the level of atmospheric CO2 (100-400 ppm). As the pressure increased from 0.1 to 0.9 MPa, CH4 production capacity with 400 ppm CO2 was enhanced from 111 to 160 μmol gcat-1. This approach in combination with the efficient catalyst shows encouraging potential for CO2 utilization, enabling direct air capture-conversion to value-added chemicals.","CO2 capture; CO2reduction; CO2utilization; direct air capture; dual-functional catalyst; methanation","en","journal article","","","","","","Accepted Author Manuscript","","2022-02-24","","","ChemE/Catalysis Engineering","","",""
"uuid:cabd41d2-550f-407a-b2d9-ccf54e368293","http://resolver.tudelft.nl/uuid:cabd41d2-550f-407a-b2d9-ccf54e368293","Optimization of intrinsic self-healing silicone coatings by benzotriazole loaded mesoporous silica","Chen, Guangmeng (Northwestern Polytechnical University); Wen, Shifeng (Northwestern Polytechnical University); Ma, Jiacheng (Northwestern Polytechnical University); Sun, Zhiyong (Luoyang Ship Material Research Institute); Lin, Cunguo (Luoyang Ship Material Research Institute); Yue, Zhufeng (Northwestern Polytechnical University); Mol, J.M.C. (TU Delft Team Arjan Mol); Liu, M. (TU Delft Energy Technology; Xi’an Jiaotong University)","","2021","Multifunctional intrinsic self-healing polymers (ISP) are gaining increasing attention these days, and many studies have been devoted to solving the conflict between achieving high mechanical polymer strength and active polymer chain diffusion. In this research, we developed an optimized self-healing composite coating by adding Benzotriazole (BTA) loaded nano silica (SiO2@BTA) to a dynamic cross-linked Polydimethylsiloxane (PDMS) network,which allows substantial and fast healing of the material integrity upon damage due to the hydrogen interaction between urea and BTA. BTA leaching tests demonstrated a longer release profile during the coating service life and corrosion tests in a 3.5 wt% NaCl aqueous solution indicated that the SiO2@BTA modified PDMS coating shows enhanced corrosion protection of carbon steel upon coating damage. Moreover, after addition of SiO2@BTA, the material failure strength increased from ~1.5 MPa to ~5.5 MPa, and the healing efficiency increased from ~59% to ~90% for 24 h healing at room temperature. Above all, this research provides an intrinsic self-healing coating design method to improve the mechanical strength and the self-healing ability of the ISP as well as enhancing the coating's corrosion protection ability.","BTA leaching; Corrosion protection; Mechanical strength; Self-healing coating; Urea hydrogen","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-12-07","","","Team Arjan Mol","","",""
"uuid:4a341807-3bad-45b0-adb1-aed96bdee4b2","http://resolver.tudelft.nl/uuid:4a341807-3bad-45b0-adb1-aed96bdee4b2","Effect of ethanol concentration on methane hydrate decomposition: MD simulation insights","Sun, Xiaoliang (China University of Petroleum - Beijing); Zhou, Guanggang (China University of Petroleum - Beijing); Liu, Z. (TU Delft ChemE/Advanced Soft Matter; China University of Petroleum - Beijing); Zhu, Jianwei (China University of Petroleum - Beijing); Guo, Fengzhi (China University of Petroleum - Beijing); Chen, Junqing (China University of Petroleum - Beijing); He, Wenhao (China University of Petroleum - Beijing); Wang, Ning (China University of Petroleum - Beijing); Zhao, Ge (China University of Petroleum - Beijing); Lu, Guiwu (China University of Petroleum - Beijing)","","2021","The controllability of mining is a key factor affecting the commercial application of methane hydrates, and the addition of chemical additives can significantly accelerate the mining process. However, the effect of additive concentration on hydrate decomposition is not yet well understood. In this study, we systematically investigate the effect of ethanol concentration on the decomposition of methane hydrate under varying thermodynamic conditions using molecular dynamics (MD) simulations. To quantitatively characterize the decomposition process and mechanism of methane hydrates, the combination of angular order parameter (AOP), radial distribution function (RDF), mean square displacement (MSD), diffusion coefficients and system energy was for the first time used. The results showed that the addition of ethanol contributed to the formation of methane bubbles and accelerated the decomposition of hydrates. The mass transfer effect of ethanol molecules and the reconstruction of the hydrogen bond network of water molecules determined the stability of hydrates. From 0 to 40 mol% ethanol concentration, the hydrate decomposition increased with increasing the concentration of ethanol. Both increasing the temperature and decreasing the pressure are beneficial to the decomposition of the hydrate system. These results provide the selection of optimal ethanol concentration for the decomposition of methane hydrate and reveal its decomposition mechanism, and shed important light for the controllable production of gas hydrates.","Decomposition; Ethanol concentration; Methane hydrate; Molecular dynamics; Thermodynamics","en","journal article","","","","","","","","","","","ChemE/Advanced Soft Matter","","",""
"uuid:8dab0b68-0720-45cf-a519-89ab6bb1a2b7","http://resolver.tudelft.nl/uuid:8dab0b68-0720-45cf-a519-89ab6bb1a2b7","Aqueous chemoenzymatic one-pot enantioselective synthesis of tertiary α-aryl cycloketonesviaPd-catalyzed C-C formation and enzymatic C=C asymmetric hydrogenation","Luan, Pengqian (Hebei University of Technology); Liu, Yunting (Hebei University of Technology; Tianjin University); Li, Yongxing (Hebei University of Technology); Chen, Ran (Hebei University of Technology); Huang, Chen (Hebei University of Technology); Gao, Jing (Hebei University of Technology); Hollmann, F. (TU Delft BT/Biocatalysis); Jiang, Yanjun (Hebei University of Technology)","","2021","An aqueous chemoenzymatic cascade reaction combining Pd-catalyzed C-C formation and enzymatic C=C asymmetric hydrogenation (AH) was developed for enantioselective synthesis of tertiary α-aryl cycloketones in good yields and excellent enantioselectivities. The stereopreference of the enzyme in AH of α-aryl cyclohexenones was studied. An enantiocomplementary enzyme was obtained by site-directed mutation.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-22","","","BT/Biocatalysis","","",""
"uuid:bf74537e-8403-4ad4-85e6-830a5ac8e368","http://resolver.tudelft.nl/uuid:bf74537e-8403-4ad4-85e6-830a5ac8e368","What motivates stakeholders to engage in collaborative innovation in the infrastructure megaprojects?","Chen, Xiaoyan (Tongji University); He, Qinghua (Tongji University); Zhang, Xinyue (Tongji University); Cao, Tingting (Tianjin University of Technology); Liu, Y. (TU Delft Integral Design & Management)","","2021","Collaborative innovation has become an innovation paradigm to improve innovation performance and firms’ economic output. However, there is relatively little research investigating stakeholders’ drivers for engaging in collaborative innovation and the relative importance of drivers in infrastructure megaprojects. This research aims to address this gap by identifying the drivers for collaborative innovation and their relative importance in the context of infrastructure megaprojects. We adopt the literature review and questionnaire survey methods to identify drivers, the Relative Importance Index to rank them, and exploratory factor analysis to group them. The results show that 18 drivers are grouped into 6 dimensions. Their rankings are as follows: responding to project and clients’ requirements, improving efficiency, gaining rewards, learning, responding to competition, responding to environmental changes. The research contributes to stake-holders’ drivers to engage in collaborative innovation and the relative importance of drivers in the context of infrastructure megaprojects. Identifying and prioritizing stakeholders’ drivers can provide practitioners with suggestions on managing the collaborative innovation process in infrastructure megaprojects.","Collaborative innovation; Drivers; Exploratory factor analysis; Infrastructure megaproject; Principal component analysis; Relative importance; OA-Fund TU Delft","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:88ef1429-ddc4-437e-a3ae-dc9de0e2a7c2","http://resolver.tudelft.nl/uuid:88ef1429-ddc4-437e-a3ae-dc9de0e2a7c2","Deep learning–based nondestructive evaluation of reinforcement bars using ground-penetrating radar and electromagnetic induction data","Li, Xiaofeng (China University of Geosciences, Wuhan); Liu, Hai (Guangzhou University); Zhou, Feng (China University of Geosciences, Wuhan); Chen, Zhongchang (China University of Geosciences, Wuhan); Giannakis, Iraklis (University of Aberdeen); Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)","","2021","This paper proposes a nondestructive evaluation method based on deep learning using combined ground-penetrating radar (GPR) and electromagnetic induction (EMI) data for autonomic and accurate estimation of the cover thickness and diameter of reinforcement bars. A real-time object detection algorithm—You Only Look Once–version 3 (YOLO v3)—is adopted to automatically identify the reinforcement bar reflected signals from radargrams, with which the range of the cover thickness is roughly predicted. Subsequently, EMI data, accompanied with the cover thickness range, are imported to a one-dimensional convolutional neural network (1D CNN), pretrained by calibrated EMI and GPR data, to simultaneously estimate the cover thickness and reinforcement bar diameter. Testing with the on-site GPR data shows that YOLO v3 is superior to Single Shot Multibox Detector method in GPR hyperbolic signal identification. Testing of 1D CNN with the EMI and GPR data collected in an in-house sand pit experiment shows that the estimation accuracy of the cover thickness and reinforcement bar diameter is, respectively, 96.8% and 90.3% with a permissible error of 1 mm. Further, an experiment with concrete specimens demonstrates that among the 22 estimated values (including the reinforcement bar diameter and cover thickness), there are 17 values accurately estimated, while the inaccurately estimated values have an error up to 2 mm. The experimental results show that the proposed method can autonomically evaluate the reinforcement bar diameter and cover thickness with a high accuracy.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2022-05-26","","","Applied Geophysics and Petrophysics","","",""
"uuid:3ba5d1d8-8d3f-46d9-800d-be016e7cbfd7","http://resolver.tudelft.nl/uuid:3ba5d1d8-8d3f-46d9-800d-be016e7cbfd7","Microbial community assembly and metabolic function in top layers of slow sand filters for drinking water production","Chen, L. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Zhai, Y. (TU Delft BT/Environmental Biotechnology; University of Twente; Oasen); van der Mark, Ed (Dunea); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); van der Meer, Walter (University of Twente; Oasen); Medema, G.J. (TU Delft Sanitary Engineering; KWR Water Research Institute; Michigan State University)","","2021","Slow sand filters (SSFs) are widely applied to treat potable water; the removal of contaminants (e.g., particles, organic matter, and microorganism) occurs primarily in the top layer. However, the development of the microbial community and its metabolic function is still poorly understood. In the present study, we analyzed the microbial quantity and community of the influents sampled from the effluent of the last step (rapid sand filtration) and of the top layers of SSFs (Schmutzdecke, 0–2 cm, 4–6 cm, 8–10 cm) sampled near terminal head loss when the Schmutzdecke (SCM) was most developed in two full-scale drinking water treatment plants (DWTPs). The two DWTPs use the same artificially recharged groundwater source. The biomass in the filter, quantified by flow cytometric intact cell counts (ICC) and adenosine triphosphate (ATP), decreased rapidly along the depth till 8–10 cm (>1 log TCC; >75% ATP); the decrease was most pronounced from the SCM to the surface sand layer (0–2 cm), after which the biomass stabilized quickly at lower depths (2–10 cm). Remarkably, beta diversity showed that SSFs layers of the same depth in two DWTPs with distinctive filter age and plant location clustered together, which indicated their insignificant effects in shaping microbial communities in SSFs. The alpha diversity indices followed the trend of the biomass, suggesting more active and diverse communities in SCM layer. PICRUSt-based function prediction revealed significant over-representation of metabolism and degradation of complex organic matters (e.g., butanoate, propanoate, xenobiotic, D-Alanine, chloroalkene, and bisphenol) in SCM layer, the functional importance of which was confirmed by the co-occurrence patterns of the dominant taxa and metabolic functions. Using an island biogeography model, we found that microbial communities in SSFs were strongly assembled by selection (68 OTUs, 50.0% sequences), rather than by simple accumulation of the microbial communities in the influents (120 OTUs, 44.8% sequences). Our findings enhance the understanding of microbial community assembly and of metabolic function in the top layers of SSFs, and constitute a valuable contribution to optimizing the design and operation of biofilters in full-scale DWTPs.","Microbial community assembly; Neutral community model; Predicted metabolic function; Schmutzdecke; Slow sand filters; Top layers","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:867583c1-7189-4240-89b3-19ee021ccac0","http://resolver.tudelft.nl/uuid:867583c1-7189-4240-89b3-19ee021ccac0","New innovations in pavement materials and engineering: A review on pavement engineering research 2021","Chen, Jiaqi (Central South University China); Dan, Hancheng (Central South University China); Ding, Yongjie (Chongqing Jiaotong University); Gao, Y. (TU Delft Pavement Engineering); Guo, Meng (Beijing University of Technology); Guo, Shuaicheng (Hunan University); Han, Bingye (Beijing University of Civil Engineering & Architecture); Hong, Bin (Harbin Institute of Technology); Hou, Yue (Beijing University of Technology); Hu, Chichun (South China University of Technology); Hu, Jing (Southeast University); Huyan, Ju (Southeast University; University of Waterloo); Jiang, Jiwang (The Hong Kong Polytechnic University); Jiang, Wei (Chang'an University); Li, Cheng (Chang'an University); Liu, Pengfei (Rheinisch-Westfälische Technische Hochschule); Liu, Yu (Chang'an University); Liu, Zhuangzhuang (Chang'an University); Lu, Guoyang (The Hong Kong Polytechnic University); Ouyang, Jian (Dalian University of Technology); Qu, Xin (Chang'an University); Ren, Dongya (Southwest Jiaotong University); Wang, Chao (Beijing University of Technology); Wang, Chaohui (Chang'an University); Wang, Dawei (Harbin Institute of Technology); Wang, Di (Aalto University); Wang, Hainian (Chang'an University); Wang, Haopeng (University of Nottingham); Xiao, Yue (Wuhan University; Wuhan University of Technology); Xing, Chao (Harbin Institute of Technology); Xu, Huining (Harbin Institute of Technology); Yan, Yu (Tongji University); Yang, Xu (Chang'an University); You, Lingyun (Huazhong University of Science and Technology); You, Zhanping (Michigan Technological University); Yu, Bin (Southeast University); Yu, Huayang (South China University of Technology); Yu, Huanan (Changsha University of Science and Technology); Zhang, Henglong (Hunan University); Zhang, Jizhe (Shandong University); Zhou, Changhong (Guilin University of Electronic Technology); Zhou, Changjun (Dalian University of Technology); Zhu, Xingyi (Tongji University)","","2021","Sustainable and resilient pavement infrastructure is critical for current economic and environmental challenges. In the past 10 years, the pavement infrastructure strongly supports the rapid development of the global social economy. New theories, new methods, new technologies and new materials related to pavement engineering are emerging. Deterioration of pavement infrastructure is a typical multi-physics problem. Because of actual coupled behaviors of traffic and environmental conditions, predictions of pavement service life become more and more complicated and require a deep knowledge of pavement material analysis. In order to summarize the current and determine the future research of pavement engineering, Journal of Traffic and Transportation Engineering (English Edition) has launched a review paper on the topic of “New innovations in pavement materials and engineering: A review on pavement engineering research 2021”. Based on the joint-effort of 43 scholars from 24 well-known universities in highway engineering, this review paper systematically analyzes the research status and future development direction of 5 major fields of pavement engineering in the world. The content includes asphalt binder performance and modeling, mixture performance and modeling of pavement materials, multi-scale mechanics, green and sustainable pavement, and intelligent pavement. Overall, this review paper is able to provide references and insights for researchers and engineers in the field of pavement engineering.","Asphalt binder; Asphalt mixture; Green and sustainable pavement; Intelligent pavement; Modeling of pavement materials; Multi-scale mechanics","en","review","","","","","","","","","","","Pavement Engineering","","",""
"uuid:b7049a08-b047-4dbf-8931-d28d1f977d86","http://resolver.tudelft.nl/uuid:b7049a08-b047-4dbf-8931-d28d1f977d86","Cluster-based flow control in hybrid software-defined wireless sensor networks","Liu, Qingzhi (Wageningen University & Research); Cheng, Long (North China Electric Power University); Alves, R.C.A.; Alves, Renan (Universidade de São Paulo); Ozcelebi, Tanir (Eindhoven University of Technology); Kuipers, F.A. (TU Delft Embedded Systems); Xu, Guixian (Tampere University); Lukkien, Johan (Eindhoven University of Technology); Chen, Shanzhi (China Academy of Telecommunication Technology)","","2021","Software-defined networking (SDN) is a cornerstone of next-generation networks and has already led to numerous advantages for data-center networks and wide-area networks. However, SDN is not widely adopted in constrained networks, such as Wireless Sensor Networks (WSN), due to excessive control overhead, lossy medium, and in-band control channels. Therefore, a key challenge to enable Software-Defined Wireless Sensor Networks (SD-WSN) is to reduce the number of control messages required to configure the data plane. In this paper, we propose a cluster-based flow control approach in hybrid SDNs. Our approach is hybrid in the sense that it takes advantage of distributed legacy routing and centralized SDN routing. In addition, it makes a trade-off between the granularity of flow control and the communication overhead induced by the SDN controller. The approach partitions a network into clusters with minimum number of border nodes. Instead of handling the individual flows of each node, the SDN controller only manages incoming and outgoing traffic flows of clusters through border nodes, while the flows inside each cluster are controlled by a distributed legacy WSN routing algorithm. Our proof-of-concept implementations in both software and hardware show that our approach is efficient with respect to reducing the number of nodes that must be managed and the number of control messages. In comparison to benchmark solutions with and without clustering, our solution reduces communication costs for flow configuration in an SD-WSN at least by 27% and at most by 88% respectively, without degrading packet delay nor delivery rate.","Flow control; Hybrid SDN; Multi-hop communication; Network cluster; Software-defined wireless sensor networks","en","journal article","","","","","","","","","","","Embedded Systems","","",""
"uuid:96720569-4beb-4416-bf7e-0cf351db91c0","http://resolver.tudelft.nl/uuid:96720569-4beb-4416-bf7e-0cf351db91c0","Evaluation of short-term streamflow prediction methods in Urban river basins","Huang, Xinxing (Shanghai Institute of Technology; Southern University of Science and Technology); Li, Yifan (Southern University of Science and Technology); Tian, Zhan (Southern University of Science and Technology); Ye, Qinghua (Deltares); Ke, Q. (TU Delft Hydraulic Structures and Flood Risk); Fan, Dongli (Shanghai Institute of Technology); Mao, Ganquan (Southern University of Science and Technology); Chen, Aifang (Southern University of Science and Technology); Liu, Junguo (Southern University of Science and Technology)","","2021","Efficient and accurate streamflow predictions are important for urban water management. Data-driven models, especially neural network (NN) models can predict streamflow fast, while the results are uncertain in some complex river systems. Physically based models can reveal the underlying physics, but it is relatively slow and computationally costly. This work focuses on evaluating the reliability of three NN models (artificial neural networks (ANN), long short-term memory networks (LSTM), adaptive neuro-fuzzy inference system (ANFIS)) and one physically based model (SOBEK) in terms of efficiency and accuracy for average and peak streamflow simulation. All the models are applied for a tidal river and a mountainous river in Shenzhen. The results show that, the ANN model calculates fastest since the hidden layer's structure is simple. The LSTM model is reliable in average streamflow simulation in tidal river with the lowest bias while the ANFIS model has the best accuracy for peak streamflow simulation. Furthermore, the SOBEK model shows reliability in simulating average and peak streamflow in mountainous river due to its ability to capture uneven spatial rainfall in the area. Overall, the results indicate that the LSTM model can be a helpful supplementary to physically based models in streamflow simulation of complex urban river systems, by giving fast streamflow predictions with usually acceptable accuracy. Our results can provide helpful information for hydrological engineers in the application of flooding early warning and emergency preparedness in the context of flooding risk management.","Neural network models; SOBEK model; Streamflow simulation; Urban rivers","en","journal article","","","","","","Accepted Author Manuscript","","2023-05-05","","","Hydraulic Structures and Flood Risk","","",""
"uuid:1ef398e5-ee81-460a-9e38-c9c7d99c86ac","http://resolver.tudelft.nl/uuid:1ef398e5-ee81-460a-9e38-c9c7d99c86ac","Moisture source variations for summer rainfall in different intensity classes over Huaihe River Valley, China","Liu, Yubo (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Zhang, Chi (Chinese Academy of Sciences); Tang, Qiuhong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Hosseini-Moghari, Seyed Mohammad (Chinese Academy of Sciences); Haile, Gebremedhin Gebremeskel (Chinese Academy of Sciences); Li, Laifang (The Pennsylvania State University); Li, Wenhong (Duke University); Yang, Kun (Tsinghua University); van der Ent, R.J. (TU Delft Water Resources); Chen, Deliang (University of Gothenburg)","","2021","Rainfall is one of the most influential climatic factors on regional development and environment, and changes in rainfall intensity are of specific concern. In the Huaihe River Valley (HRV), heavy rainfall is a primary trigger of floods. However, the difference in the origin of moisture contributed to heavy rainfall and light rainfall is rarely studied and not entirely understood. This study analyzes the rainfall moisture sources in association with different categories of rainfall intensity over the HRV during 1980–2018 using the Water Accounting Model with ERA-Interim reanalysis and precipitation observations from China Meteorological Administration. The results show that the moisture for the HRV summer rainfall is mainly from terrestrial subregion (40%), the Indian Ocean (27%), the Pacific Ocean (25%), and the local HRV (8%). In addition, moisture sources differ substantially between light and heavy rainfall. Specifically, the local HRV contributes more moisture to light rainfall (12%) compared to heavy rainfall (4%), whereas the Indian Ocean contributes more to heavy rainfall (33%) than to light rainfall (20%). The grids located in the southern source region make higher contribution ratio in heavy rainfall than in light rainfall. These results suggest that moisture from distant oceanic areas, especially the Indian Ocean, plays a crucial role in intense summer rainfall, whereas moisture from the land sources covering local grids plays a dominant role in light rainfall in the HRV.","Heavy rainfall; Huaihe River; Indian Ocean; Moisture source; Water Accounting Model","en","journal article","","","","","","","","2021-10-10","","","Water Resources","","",""
"uuid:61de8af3-5944-4552-b26b-98b3c5868016","http://resolver.tudelft.nl/uuid:61de8af3-5944-4552-b26b-98b3c5868016","Knitting 4D garments with elasticity controlled for body motion","Liu, Z. (TU Delft Materials and Manufacturing; Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Han, Xingjian (Boston University); Zhang, Yuchen (Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Chen, Xiangjia (Centre for Perceptual and Interactive Intelligence Limited, Hong Kong); Lai, Y. (Cardiff University); Doubrovski, E.L. (TU Delft Mechatronic Design); Whiting, Emily (Boston University); Wang, C.C. (The University of Manchester)","","2021","In this paper, we present a new computational pipeline for designing and fabricating 4D garments as knitwear that considers comfort during body movement. This is achieved by careful control of elasticity distribution to reduce uncomfortable pressure and unwanted sliding caused by body motion. We exploit the ability to knit patterns in different elastic levels by single-jersey jacquard (SJJ) with two yarns. We design the distribution of elasticity for a garment by physics-based computation, the optimized elasticity on the garment is then converted into instructions for a digital knitting machine by two algorithms proposed in this paper. Specifically, a graph-based algorithm is proposed to generate knittable stitch meshes that can accurately capture the 3D shape of a garment, and a tiling algorithm is employed to assign SJJ patterns on the stitch mesh to realize the designed distribution of elasticity. The effectiveness of our approach is verified on simulation results and on specimens physically fabricated by knitting machines.","4D garment; computational fabrication; elasticity control; knitting","en","journal article","","","","","","Accepted Author Manuscript","","","","","Materials and Manufacturing","","",""
"uuid:074a4232-5768-41bc-8961-b473e651b0f9","http://resolver.tudelft.nl/uuid:074a4232-5768-41bc-8961-b473e651b0f9","A Switched-Capacitor DC-DC Converter Powering an LC Oscillator to Achieve 85% System Peak Power Efficiency and -65 dBc Spurious Tones","Urso, A. (TU Delft Bio-Electronics); Chen, Y. (TU Delft Electronic Instrumentation); Staszewski, R.B. (TU Delft Electronics); Dijkhuis, Johan F. (Holst Centre); Stanzione, Stefano (Holst Centre); Liu, Y. (TU Delft Bio-Electronics); Serdijn, W.A. (TU Delft Bio-Electronics); Babaie, M. (TU Delft Electronics)","","2020","In this paper, we propose a new scheme to directly power a 4.9-5.6GHz LC oscillator from a recursive switched-capacitor DC-DC converter. A finite-state machine is integrated to automatically adjust the conversion ratio and switching frequency of the converter such that its DC output voltage is within ±5% of the desired 1V across input voltage range 1.3-2.2V and < 2mA load current conditions. A gate-driver circuit is embedded in each switch of the converter to guarantee constant on-resistance across PVT variations without sacrificing device reliability. Furthermore, a spur reduction block (SRB) is embedded in the oscillator to suppress the ripple induced spurs by stabilizing its tail current. Both the converter and the oscillator are implemented in 40-nm CMOS technology. The measured peak power efficiency of the converter is 87%, while its spot noise is < 1.5nV/Hz which does not degrade the phase noise of the oscillator. The SRB suppresses the spur to <-65dBc under the 30mVpp ripple of the converter.","LC oscillator; LDO replacement; Switched-capacitor DC-DC converter; gate-driver circuit; phase noise; spur reduction block; voltage controlled oscillator (VCO)","en","journal article","","","","","","accepted author manuscript","","","","","Bio-Electronics","","",""
"uuid:b8216444-4ab9-4c35-9246-646a4bdf7a1d","http://resolver.tudelft.nl/uuid:b8216444-4ab9-4c35-9246-646a4bdf7a1d","Analysis and Design of Power Supply Circuits for RF Oscillators","Urso, A. (TU Delft Bio-Electronics); Chen, Y. (TU Delft Electronic Instrumentation); Dijkhuis, Johan F. (Holst Centre); Liu, Yao-Hong (Holst Centre); Babaie, M. (TU Delft Electronics); Serdijn, W.A. (TU Delft Bio-Electronics)","","2020","This article presents guidelines for designing the power supply blocks of RF oscillators. To preserve their spectral purity, the requirements on the noise and ripple of the supply voltage are firstly evaluated based on the oscillator supply pushing factor and the oscillator Figure-of-Merit (FOM). Those specifications are then employed to design and estimate the power efficiency of an analog low-dropout regulator (LDO) and a switched-capacitor DC-DC converter. As a proof of concept, a 2:1 or 3:2 switched-capacitor DC-DC converter is implemented and directly connected to our previously published 4.9-5.5 GHz LC oscillator. The converter provides a 1V supply voltage with a noise ≤0.9nV/√Hz at 1MHz and does not affect the inherent phase noise of the oscillator. The ripple amplitude of the converter is 30mV while its effect is suppressed by the spur reduction block embedded in the oscillator.","LC oscillator; LDO; Power supply requirements; noise analysis; reverse isolation of power supply circuits; spur reduction block; switched-capacitor DC-DC converter","en","journal article","","","","","","","","","","","Bio-Electronics","","",""
"uuid:750df5f0-1b27-4cb4-b8c4-ec7bc9aced02","http://resolver.tudelft.nl/uuid:750df5f0-1b27-4cb4-b8c4-ec7bc9aced02","Assessing the transition effects in a drinking water distribution system caused by changing supply water quality: an indirect approach by characterizing suspended solids","Chen, L. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Ling, Fangqiong (Washington University in St. Louis); Bakker, Geo (Vitens N.V.); Liu, Wen Tso (University of Illinois at Urbana-Champaign); Medema, G.J. (Chinese Academy of Sciences; KWR Water Research Institute); van der Meer, W.G.J. (Oasen; University of Twente); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences)","","2020","Worldwide, it is common that the drinking water distribution systems (DWDSs) may be subjected to changes of supply water quality due to the needs of upgrading the treatment processes or switching the source water. However, the potential impacts of quality changed supply water on the stabilized ecological niches within DWDSs and the associated water quality deterioration risks were poorly documented. In the present study, such transition effects caused by changing the supply water quality that resulted from destabilization of biofilm and loose deposits in DWDS were investigated by analyzing the physiochemical and microbiological characteristics of suspended particles before (T0), during (T3-weeks) and after upgrading the treatments (T6-months) in an unchlorinated DWDS in the Netherlands. Our results demonstrated that after 6 months’ time the upgraded treatments significantly improved the water quality. Remarkably, water quality deterioration was observed at the initial stage when the quality-improved treated water distributed into the network at T3-weeks, observed as a spike of total suspended solids (TSS, 50–260%), active biomass (ATP, 95–230%) and inorganic elements (e.g. Mn, 130–250%). Furthermore, pyrosequencing results revealed sharp differences in microbial community composition and structure for the bacteria associated with suspended particles between T0 and T3-weeks, which re-stabilized after 6 months at T6-months. The successful capture of transition effects was especially confirmed by the domination of Nitrospira spp. and Polaromonas spp. in the distribution system at T3-weeks, which were detected at rather low relative abundance at treatment plant. Though the transitional effects were captured, this study shows that the introduction of softening and additional filtration did not have an effect on the water quality for the consumer which improved considerably after 6-months’ period. The methodology of monitoring suspended particles with MuPFiSs and additional analysis is capable of detecting transitional effects by monitoring the dynamics of suspended particles and its physiochemical and microbiological composition.","Drinking water distribution system; Suspended solids; Transition effects; Upgrading treatments; Water quality deterioration risks","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:4bd78b06-05a9-4536-ba91-65a40891310d","http://resolver.tudelft.nl/uuid:4bd78b06-05a9-4536-ba91-65a40891310d","A systematic literature review on safety research related to chemical industrial parks","Zeng, Tao (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety); Chen, Guohua (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety); Yang, Yunfeng (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety; Katholieke Universiteit Leuven); Reniers, G.L.L.M.E. (TU Delft Safety and Security Science; Katholieke Universiteit Leuven; Universiteit Antwerpen); Zhao, Yixin (South China University of Technology; Guangdong Provincial Science and Technology Collaborative Innovation Center for Work Safety); Liu, Xia (Guangdong Academy of Safety Science and Technology, Guangzhou)","","2020","The increasing demand for chemical products has driven the construction and development of chemical industrial areas, or so-called 'chemical industrial parks' (CIPs), but this has intrinsically raised the risk of major accidents. Therefore, it is significant and urgent to summarize the state of art and research needs in the field of CIP safety. In this paper, a keyword co-occurrence analysis of 116 scientific articles was conducted to support the classification of research topics in this field, then an overview of those research topics was presented to investigate the evolution of safety research with respect to CIPs. Specifically, the way that safety assessments are conducted, as well as how safety management and safety technology in such areas are classified and investigated, followed by detailed descriptions of representative methods and their contributions to CIP safety, are discussed. An integrated safety framework for CIPs is proposed to organize safety approaches and measures systematically. Based on the classification and analysis of studies on management, assessment, and technology related to CIP safety, the research trends and future directions and challenges are discussed and outlined. Those results are useful for improving theoretical method and industrial strategies, and can advance the safety and sustainability development of CIPs.","Chemical industrial park; Review; Safety assessment; safety framework; Safety management; Safety technology; Trend","en","review","","","","","","","","","","","Safety and Security Science","","",""
"uuid:cae10df9-0bbf-4a1f-99f6-73242e74972f","http://resolver.tudelft.nl/uuid:cae10df9-0bbf-4a1f-99f6-73242e74972f","Multi-parametric assessment of biological stability of drinking water produced from groundwater: Reverse osmosis vs. conventional treatment","Sousi, Mohaned (IHE Delft Institute for Water Education; University of Twente); Liu, G. (TU Delft Sanitary Engineering; Chinese Academy of Sciences); Salinas-Rodriguez, Sergio G. (IHE Delft Institute for Water Education); Chen, L. (TU Delft Sanitary Engineering); Dusseldorp, Jos (Oasen); Wessels, Peter (Oasen); Schippers, Jan C. (IHE Delft Institute for Water Education); Kennedy, M.D. (TU Delft Sanitary Engineering; IHE Delft Institute for Water Education); van der Meer, Walter (University of Twente; Oasen)","","2020","Although water produced by reverse osmosis (RO) filtration has low bacterial growth potential (BGP), post-treatment of RO permeate, which is necessary prior to distribution and human consumption, needs to be examined because of the potential re-introduction of nutrients/contaminants. In this study, drinking water produced from anaerobic groundwater by RO and post-treatment (ion exchange, calcite contactors, and aeration) was compared with that produced by conventional treatment comprising (dry) sand filtration, pellet softening, rapid sand filtration, activated carbon filtration, and UV disinfection. The multi-parametric assessment of biological stability included bacterial quantification, nutrient concentration and composition as well as bacterial community composition and diversity. Results showed that RO permeate remineralised in the laboratory has an extremely low BGP (50 ± 12 × 103 ICC/mL), which increased to 130 ± 10 × 103 ICC/mL after site post-treatment. Despite the negative impact of post-treatment, the BGP of the finished RO-treated water was >75% lower than that of conventionally treated water. Organic carbon limited bacterial growth in both RO-treated and conventionally treated waters. The increased BGP in RO-treated water was caused by the re-introduction of nutrients during post-treatment. Similarly, OTUs introduced during post-treatment, assigned to the phyla of Proteobacteria and Bacteroidetes (75–85%), were not present in the source groundwater. Conversely, conventionally treated water shared some OTUs with the source groundwater. It is clear that RO-based treatment achieved an extremely low BGP, which can be further improved by optimising post-treatment, such as using high purity calcite. The multi-parametric approach adopted in this study can offer insights into growth characteristics including limiting nutrients (why) and dominating genera growing (who), which is essential to manage microbiological water quality in water treatment and distribution systems.","Bacterial growth potential (BGP); Biological stability; Limiting nutrient; Multi-parametric approach; Reverse osmosis (RO); Trace elements","en","journal article","","","","","","","","","","","Sanitary Engineering","","",""
"uuid:aa45eae7-3504-40e8-a4d1-2f12d8cb3edb","http://resolver.tudelft.nl/uuid:aa45eae7-3504-40e8-a4d1-2f12d8cb3edb","Protection Testing for Multiterminal High-Voltage dc Grid: Procedures and Assessment","Liu, Z. (Aalborg University); Mirhosseini, S.S. (Iran University of Science and Technology); Popov, M. (TU Delft Intelligent Electrical Power Grids); Audichya, Yash (ABB); Colangelo, Daniele (Swiss Federal Institute of Technology); Jamali, Sadegh (Iran University of Science and Technology); Palensky, P. (TU Delft Intelligent Electrical Power Grids); Hu, Weihao (University of Electronic Science and Technology of China); Chen, Zhe (Aalborg University)","","2020","eAssessment The application of multiterminal (MT), high-voltage dc (HVdc) (MTdc) grid technology requires test procedures for the operation and implementation of the protection solutions. The test procedures are usually derived from experience and from extensive measurement data, which, at present, are still not widely available. Based on a hardware-inthe- loop (HIL) method, advanced dc protection testing strategies, utilizing existing experience for ac grids and requirements for MTdc grids, may overcome this gap.","","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2021-08-17","","","Intelligent Electrical Power Grids","","",""
"uuid:032a2a71-9073-4264-8315-6c268c63d4d9","http://resolver.tudelft.nl/uuid:032a2a71-9073-4264-8315-6c268c63d4d9","Optimizing the preheating temperature of hot rolled slab from the perspective of the oxidation kinetic","Zhang, Hua (Wuhan University of Science and Technology); Yu, Li (Wuhan University of Science and Technology); Liu, Tao (Wuhan University of Science and Technology); Ni, Hongwei (Wuhan University of Science and Technology); Li, Y. (TU Delft (OLD) MSE-3; Wuhan University of Science and Technology); Chen, Z. (TU Delft (OLD) MSE-3; Flemish Institute for Technological Research); Yang, Y. (TU Delft Team Yongxiang Yang)","","2020","Decreasing the preheating temperature is an effective step to control the energy consumption in the hot rolling process. In order to obtain the lowest preheating temperature to prepare enough thickness of oxide scale in the hot rolling process, the oxidation resistance of commercial steel samples with different Al and Si contents were investigated in this paper. The results indicate that both Al and Si based oxides form at the steel-oxides interface as diffusion barrier but Al provide stronger diffusion resistance than Si in the diffusion-controlling oxidation region. Meanwhile, a three-dimensional oxidation kinetic model has been adopted to depict the oxidation behavior of four types of commercial steel. The oxidation process of automotive steel sample containing with low alloy elements is kinetically determined by interface chemical reaction. Its activation energy is 55.2 ± 6.9 kJ/mol. As for silicon steel containing with relative high alloy elements, its controlling process is determined by diffusion step at low temperature and controlled by chemical reaction rate at high temperature. In order to obtain enough thickness of oxide scale, the lowest preheating temperature of different types steel range from high to low should be the steel with high content of Al (1180 °C), the steel with high content of Si and low content of Al (1130 °C) and the steel with high contents of Si and Al (1030 °C).","Alloy elements; Hot rolling; Oxidation kinetic; Oxide scale","en","journal article","","","","","","","","","","","(OLD) MSE-3","","",""
"uuid:f038ff1f-618b-414d-9bc4-3d6a269d64b1","http://resolver.tudelft.nl/uuid:f038ff1f-618b-414d-9bc4-3d6a269d64b1","An indicator system for evaluating operation and maintenance management of mega infrastructure projects in China","Chen, Dan (Chongqing University); Xiang, Pengcheng (Chongqing University); Jia, Fuyuan (Chongqing University); Zhang, Jian (Chongqing University); Liu, Z. (TU Delft Integral Design & Management)","","2020","Mega infrastructure projects provide a basic guarantee for social development, economic construction, and livelihood improvement. Their operation and maintenance (O&M) management are of great significance for the smooth operation and the realization of the value created by the projects. In order to provide an approach for effectively evaluating O&M management, this study develops a holistic indicator system using a mixed-review method from the national macro perspective in China. In this study, literature analysis, policy texts, expert interviews, and grounded theory were used to collect relevant data at home and abroad, and establish an initial evaluation indicator system with 23 indicators covering two dimensions and five aspects. Then the questionnaire survey and factor analysis were used to score and categorize the indicators, and finally an evaluation indicator system for O&M management of mega infrastructure projects was formed. The results show that social relations, environmental benefits, macro policy, and operational capacities play an important role in the evaluation of the O&M of mega infrastructure projects. This study helps the management team to avoid negative impacts in the O&M management of mega infrastructure projects and lays a theoretical foundation for future research. The indicator system in this study is based on the Chinese context, and it remains to be verified whether the indicator system is applicable to other countries due to the differences in political and cultural backgrounds in different regions.","Assessment level; Indicator system; Mega infrastructure projects; Operation and maintenance management","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:e64b3d1a-cd3d-4605-ad3c-01054cd4db57","http://resolver.tudelft.nl/uuid:e64b3d1a-cd3d-4605-ad3c-01054cd4db57","Nonreciprocal coherent coupling of nanomagnets by exchange spin waves","Wang, Hanchen (Beihang University); Chen, Jilei (Beihang University); Yu, T. (Max Planck Institute for the Structure and Dynamics of Matter, Hamburg); Liu, Chuanpu (Beihang University); Guo, Chenyang (University of Chinese Academy of Sciences); Liu, Song (Southern University of Science and Technology); Shen, Ka (Beijing Normal University); Jia, Hao (Southern University of Science and Technology); Bauer, G.E. (TU Delft QN/Bauer Group; Kavli institute of nanoscience Delft; Tohoku University; Rijksuniversiteit Groningen)","","2020","Nanomagnets are widely used to store information in non-volatile spintronic devices. Spin waves can transfer information with low-power consumption as their propagations are independent of charge transport. However, to dynamically couple two distant nanomagnets via spin waves remains a major challenge for magnonics. Here we experimentally demonstrate coherent coupling of two distant Co nanowires by fast propagating spin waves in an yttrium iron garnet thin film with sub-50 nm wavelengths. Magnons in two nanomagnets are unidirectionally phase-locked with phase shifts controlled by magnon spin torque and spin-wave propagation. The coupled system is finally formulated by an analytical theory in terms of an effective non-Hermitian Hamiltonian. Our results are attractive for analog neuromorphic computing that requires unidirectional information transmission. [Figure not available: see fulltext.]","coherent coupling; nanomagnets; nonreciprocity; spin waves; spintronics","en","journal article","","","","","","Accepted Author Manuscript","","2021-12-28","","","QN/Bauer Group","","",""
"uuid:a07f9851-1949-43f8-ae79-9b4518a3f367","http://resolver.tudelft.nl/uuid:a07f9851-1949-43f8-ae79-9b4518a3f367","Workload-Adaptive Configuration Tuning for Hierarchical Cloud Schedulers","Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Zong, Zan (Tsinghua University); Chen, Lydia Y. (TU Delft Data-Intensive Systems); Liu, Wending (Beijing Institute of Technology); Wang, Siyi (Institute of Computing Technology Chinese Academy of Sciences); Zhan, Jianfeng (Institute of Computing Technology Chinese Academy of Sciences)","","2019","Cluster schedulers provide flexible resource sharing mechanism for best-effort cloud jobs, which occupy a majority in modern datacenters. Properly tuning a scheduler's configurations is the key to these jobs' performance because it decides how to allocate resources among them. Today's cloud scheduling systems usually rely on cluster operators to set the configuration and thus overlook the potential performance improvement through optimally configuring the scheduler according to the heterogeneous and dynamic cloud workloads. In this paper, we introduce AdaptiveConfig, a run-time configurator for cluster schedulers that automatically adapts to the changing workload and resource status in two steps. First, a comparison approach estimates jobs' performances under different configurations and diverse scheduling scenarios. The key idea here is to transform a scheduler's resource allocation mechanism and their variable influence factors (configurations, scheduling constraints, available resources, and workload status) into business rules and facts in a rule engine, thereby reasoning about these correlated factors in job performance comparison. Second, a workload-adaptive optimizer transforms the cluster-level searching of huge configuration space into an equivalent dynamic programming problem that can be efficiently solved at scale. We implement AdaptiveConfig on the popular YARN Capacity and Fair schedulers and demonstrate its effectiveness using real-world Facebook and Google workloads, i.e., successfully finding best configurations for most of scheduling scenarios and considerably reducing latencies by a factor of two with low optimization time.","Cloud datacenter; cluster scheduler; configuration; job latency; YARN","en","journal article","","","","","","","","","","","Data-Intensive Systems","","",""
"uuid:b9fefd3f-a9fc-45ba-8c6b-ef30361ca341","http://resolver.tudelft.nl/uuid:b9fefd3f-a9fc-45ba-8c6b-ef30361ca341","SlimML: Removing Non- critical Input Data in Large-scale Iterative Machine Learning","Han, Rui (Beijing Institute of Technology); Liu, Chi Harold (Beijing Institute of Technology); Li, Shilin (Beijing Institute of Technology); Chen, Lydia Y. (TU Delft Dataintensive Systems); Wang, Guoren (Beijing Institute of Technology); Tang, Jian (DiDi AI Labs); Ye, Jieping (DiDi AI Labs)","","2019","The core of many large-scale machine learning (ML) applications, such as neural networks (NN), support vector machine (SVM), and convolutional neural network (CNN), is the training algorithm that iteratively updates model parameters by processing massive datasets. From a plethora of studies aiming at accelerating ML, being data parallelization and parameter server, the prevalent assumption is that all data points are equivalently relevant to model parameter updating. In this article, we challenge this assumption by proposing a criterion to measure a data point's effect on model parameter updating, and experimentally demonstrate that the majority of data points are non-critical in the training process. We develop a slim learning framework, termed SlimML, which trains the ML models only on the critical data and thus significantly improves training performance. To such an end, SlimML efficiently leverages a small number of aggregated data points per iteration to approximate the criticalness of original input data instances. The proposed approach can be used by changing a few lines of code in a standard stochastic gradient descent (SGD) procedure, and we demonstrate experimentally, on NN regression, SVM classification, and CNN training, that for large datasets, it accelerates model training process by an average of 3.61 times while only incurring accuracy losses of 0.37 percent.","Iterative machine learning; MapReduce; large input datasets; model parameter updating","en","journal article","","","","","","","","","","","Dataintensive Systems","","",""
"uuid:f3301dad-e141-41b7-ad32-de74e9dab490","http://resolver.tudelft.nl/uuid:f3301dad-e141-41b7-ad32-de74e9dab490","A Supply Pushing Reduction Technique for LC Oscillators Based on Ripple Replication and Cancellation","Chen, Y. (TU Delft Electronics); Liu, Yao-Hong (Holst Centre); Zong, Z. (TU Delft Electronics); Dijkhuis, Johan (Holst Centre); Dolmans, Guido (Holst Centre); Staszewski, R.B. (University College Dublin); Babaie, M. (TU Delft Electronics)","","2019","In this paper, we propose a method to suppress supply pushing of an LC oscillator such that it may directly operate from a switched-mode dc-dc converter generating fairly large ripples. A ripple replication block (RRB) generates an amplified ripple replica at the gate terminal of the tail current source to stabilize the oscillator's tail current and thus its oscillating amplitude. The parasitic capacitance of the active devices and correspondingly the oscillation frequency are stabilized in turn. A calibration loop is also integrated on-chip to automatically set the optimum replication gain that minimizes the variation of the oscillation amplitude. A 4.9-5.6-GHz oscillator is realized in 40-nm CMOS and occupies 0.23 mm² while consuming 0.8-1.3 mW across the tuning range (TR). The supply pushing is improved to <1 MHz/V resulting in a low <-49-dBc spur due to 0.5-12-MHz sinusoidal supply ripples as large as 50 mVpp. We experimentally verify the effectiveness of the proposed technique also in face of saw-tooth, multi-tone, and modulated supply ripples.","Common-mode resonance; current-biased oscillator; dc-dc converter; digitally controlled oscillator (DCO); foreground calibration; Frequency conversion; LC oscillator; LC oscillators; power supply rejection (PSR); ripple replication and cancellation; supply pushing; voltage-controlled oscillator (VCO).; ommon-mode resonance; voltage-controlled oscillator (VCO)","en","journal article","","","","","","","","","","","Electronics","","",""
"uuid:5ce32d42-9663-4a06-81da-66f70c8ef8aa","http://resolver.tudelft.nl/uuid:5ce32d42-9663-4a06-81da-66f70c8ef8aa","Revealing an Interconnected Interfacial Layer in Solid-State Polymer Sodium Batteries","Zhao, Chenglong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Liu, Lilu (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Lu, Yaxiang (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Wagemaker, M. (TU Delft RST/Storage of Electrochemical Energy); Chen, Liquan (Chinese Academy of Sciences); Hu, Yong Sheng (Chinese Academy of Sciences; University of Chinese Academy of Sciences; Yangtze River Delta Physics Research Center, Liyang)","","2019","Replacing the commonly used nonaqueous liquid electrolytes in rechargeable sodium batteries with polymer solid electrolytes is expected to provide new opportunities to develop safer batteries with higher energy densities. However, this poses challenges related to the interface between the Na-metal anode and polymer electrolytes. Driven by systematically investigating the interface properties, an improved interface is established between a composite Na/C metal anode and electrolyte. The observed chemical bonding between carbon matrix of anode with solid polymer electrolyte, prevents delamination, and leads to more homogeneous plating and stripping, which reduces/suppresses dendrite formation. Full solid-state polymer Na-metal batteries, using a high mass loaded Na3V2(PO4)3 cathode, exhibit ultrahigh capacity retention of more than 92 % after 2 000 cycles and over 80 % after 5 000 cycles, as well as the outstanding rate capability.","composite metal anodes; interfacial layers; sodium batteries; solid polymer electrolytes; stable cycling","en","journal article","","","","","","Accepted Author Manuscript","","2020-09-25","","","RST/Storage of Electrochemical Energy","","",""
"uuid:11523521-351a-44e6-802a-34e4c40ccd22","http://resolver.tudelft.nl/uuid:11523521-351a-44e6-802a-34e4c40ccd22","Fluidization dynamics of cohesive Geldart B particles. Part I: X-ray tomography analysis","Ma, Jiliang (Southeast University); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering); Liu, Daoyin (Southeast University); Mudde, R.F. (TU Delft ImPhys/Imaging Physics; TU Delft Executive board); Chen, Xiaoping (Southeast University); Wagner, E.C. (TU Delft ChemE/Afdelingsbureau); Liang, Cai (Southeast University)","","2019","Due to the presence of inter-particle cohesive force, cohesive particles reveal totally different fluidization behaviors as compared to the non-cohesive system. This paper studies the fluidization dynamics of Geldart B particles with varying thermal-induced cohesive forces. Multi-source X-ray tomography was applied to reconstruct 3D temporal images of bubbles, based on which, various bubble properties were extracted. The results show that increasing cohesive force will decrease bubble number while increase bubble size, implying that the presence of cohesive force facilitates bubble coalescence. By examining the bubble size distribution, cohesive force is found to have no effect on the number of median bubbles but greatly influence small and large bubbles. When the cohesive force is strong, the bubbles grow to a considerable size similar with bed dimension, giving rise to slugging near bed surface. With the action of inter-particle cohesive force, particle slug gradually grows by capturing other freely fluidizing particles, finally inducing “whole-bed” slugging. The particle slug may rupture in the rising process, and the bed turns back to normal fluidization. In comparison to normal bubbles, the gas slug has much larger size but far smaller frequency. The rise velocity of gas slug is also very low due to the particle-wall friction and gas-solid momentum dissipation. Therefore, the averaged values of bubble properties dramatically changed as bed temperature exceeds 35 °C. When the temperature attains 45 °C, the cohesive force is so strong that the fluidization completely fails in terms of stable whole-bed slugging.","Bubble; Cohesive particle; Fluidization; Slugging; X-ray tomography","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-05-12","","ImPhys/Imaging Physics","ChemE/Product and Process Engineering","","",""
"uuid:aa175f43-0430-4105-8cf2-92705c026842","http://resolver.tudelft.nl/uuid:aa175f43-0430-4105-8cf2-92705c026842","Fluidization dynamics of cohesive Geldart B particles. Part II: Pressure fluctuation analysis","Ma, Jiliang (Southeast University); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering); Liu, Daoyin (Southeast University); Mudde, R.F. (TU Delft Executive board); Chen, Xiaoping (Southeast University); Pan, Suyang (Southeast University); Liang, Cai (Southeast University)","","2019","The increase of inter-particle cohesive force greatly changes the fluidization dynamics, finally leading to the partial or complete failure of fluidization. However, few studies concern such transition process. This paper investigates the fluidization dynamics of Geldart B particles with a wide-range of cohesive force by analyzing the in-bed pressure fluctuation signals. Combining the bubble information reported in Part I, the local and global fluidization dynamics under different cohesive forces were discussed. The results show that bulk bubble dynamics is weaken with the presence of inter-particle cohesive force. As the force increases, fluidization changes from multi-bubbling regime to single-bubble regime and the factor governing the pressure fluctuation changes from bubble formation to bubble eruption. When the cohesive force is strong, slugging appears near the bed surface, then gradually extends toward the bottom bed by capturing freely fluidizing particles, and finally develops into the whole-bed slugging. At this time, regular fluidization turns into an alternative process between whole-bed slugging and regular status, corresponding to two distinct peaks in power spectral density of pressure signals at 0.1 Hz and 1 Hz respectively. The size of gas slug decreases with the elevation of measurement height. Basically, any operations that promote bubble growth will also facilitate the appearance of whole-bed slugging under strong cohesive force. Reducing the static bed height is a preferable approach to weaken, or even avoid the defluidization of whole-bed slugging, without changing other operational parameters.","Cohesive particle; Defluidization; Fluidization; Pressure fluctuation; Slugging","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-08-26","","Executive board","ChemE/Product and Process Engineering","","",""
"uuid:138ca6a3-69da-40f7-bcb3-e2d8369ed3f1","http://resolver.tudelft.nl/uuid:138ca6a3-69da-40f7-bcb3-e2d8369ed3f1","Moisture source changes contributed to different precipitation changes over the northern and southern Tibetan Plateau","Zhang, Chi (Chinese Academy of Sciences); Tang, Qiuhong (Chinese Academy of Sciences; University of Chinese Academy of Sciences); Chen, Deliang (University of Gothenburg; Chinese Academy of Sciences); van der Ent, R.J. (TU Delft Water Resources; Universiteit Utrecht); Liu, Xingcai (Chinese Academy of Sciences); Li, Wenhong (Duke University); Haile, Gebremedhin Gebremeskel (Chinese Academy of Sciences)","","2019","Precipitation on the Tibetan Plateau (TP) showed different spatial changes during 1979-2016, with an increasing trend over the northern Tibetan Plateau (NTP) and a slightly negative trend over the southern Tibetan Plateau (STP). The changes in precipitation moisture sources over the NTP and STP are investigated using the improved Water Accounting Model with an atmospheric reanalysis as well as observational precipitation and evaporation data. The results show the region in the northwest (region NW), ranging from the TP to Europe dominated by the westerlies, provides 38.9% of precipitation moisture for the NTP, and the region in the southeast (region SE), ranging from the TP to the Indian Ocean and Indochina dominated by the Asian monsoons, provides 51.4% of precipitation moisture for the STP. For the precipitation increase over the NTP, the SE and TP are the main contributors, contributing around 35.8% and 51.7% of the increase, respectively. The contributions from the SE and TP to the STP are, however, minor and insignificant. Meanwhile, the NW shows a negative trend of -4.2 ± 2.9mmyr -1 decade -1 (significant at the 0.01 level), which contributes to the negative precipitation trend over the STP. Results during the wet season indicate that moisture sources from the areas dominated by the Asian monsoons have contributed more precipitated moisture for the NTP, but not for the STP. Further analysis reveals that precipitated moisture originating from the Indian subcontinent has increased for the NTP while it has decreased for the STP during 1979-2016.","Climate change; Climatology; Moisture/moisture budget; Water budget","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-08-04","","","Water Resources","","",""
"uuid:6293181b-1df1-49b0-aeaf-ccae1f092b40","http://resolver.tudelft.nl/uuid:6293181b-1df1-49b0-aeaf-ccae1f092b40","Relational model of accidents and vessel traffic using AIS Data and GIS: A case study of the Western port of Shenzhen City","Li, Mengxia (Wuhan University of Technology; Hubei Key Laboratory of Inland Shipping Technology); Mou, Junmin (Hubei Key Laboratory of Inland Shipping Technology; Wuhan University of Technology); Liu, Rongfang (New Jersey Institute of Technology); Chen, P. (TU Delft Safety and Security Science); Dong, Zhuojian (Hubei Key Laboratory of Inland Shipping Technology; Wuhan University of Technology); He, Yixiong (Hubei Key Laboratory of Inland Shipping Technology; Wuhan University of Technology)","","2019","Following the growth in global trade activities, vessel traffic has increased dramatically in some busy waterways and ports. However, such increments have made it more complex to manage the regional vessel traffic, which can increase the risk of an accident in the area. To model and analyze the relationship between vessel traffic and maritime traffic, this paper proposes a gridded geography information system (GIS)-based relation analysis model using the historical automatic identification system (AIS) data and accident records over a 10-year-span. Firstly, the extent of the hazards posed by a maritime accident in terms of hull loss, fatality, and direct economic loss is quantified using set pair analysis. Consequently, the hazardous degree posed by an accident is obtained. The relative consequence of the regional hazard (RCORH) is then estimated by summing up all the relative hazardous degrees of accidents that have occurred in a certain gridded area. Secondly, the vessel traffic in the gridded areas is analyzed using characteristics such as speed, heading variance, and traffic volume as indicators. Based on the analysis of both the maritime traffic accidents and the vessel traffic, the spatial relationships are analyzed with an overlay between the RCORH and vessel traffic data of each grid, as well as a regression analysis. In a case study of the Western port of Shenzhen City, China, the methodology proves to be effective for vessel traffic management and traffic engineering design.","Collision accident; Maritime safety; Relation model; Set pair analysis; Vessel traffic","en","journal article","","","","","","","","","","","Safety and Security Science","","",""
"uuid:d1ef55f7-0190-4082-9603-08bec81d6850","http://resolver.tudelft.nl/uuid:d1ef55f7-0190-4082-9603-08bec81d6850","Relaxing the control-gain assumptions of DSC design for nonlinear MIMO systems","Chen, Yong (Air Force Engineering University); Lv, Maolong (TU Delft Team Bart De Schutter); Baldi, S. (TU Delft Team Bart De Schutter; Southeast University); Liu, Zongcheng (Air Force Engineering University); Zhang, Wenqian (Air Force Engineering University); Zhou, Yang (Air Force Engineering University)","","2019","This work focuses on adaptive neural dynamic surface control (DSC) for an extended class of nonlinear MIMO strict-feedback systems whose control gain functions are continuous and possibly unbounded. The method is based on introducing a compact set which is eventually proved to be an invariant set: thanks to this set, the restrictive assumption that the upper and lower bounds of control gain functions must be bounded is removed. This method substantially enlarges the class of systems for which DSC can be applied. By utilizing Lyapunov theorem and invariant set theory, it is rigorously proved that all signals in the closed-loop systems are semi-globally uniformly ultimately bounded (SGUUB) and the output tracking errors converge to an arbitrarily small residual set. A simulation example is provided to demonstrate the effectiveness of the proposed approach.","Adaptive systems; MIMO communication; Stability analysis; Nonlinear systems; Backstepping; Control design","en","conference paper","IEEE","","","","","Accepted Author Manuscript","","","","","Team Bart De Schutter","","",""
"uuid:710753aa-bdf0-4bf1-8fce-803672ba2417","http://resolver.tudelft.nl/uuid:710753aa-bdf0-4bf1-8fce-803672ba2417","Excitation of unidirectional exchange spin waves by a nanoscale magnetic grating","Chen, Jilei (Beihang University); Yu, T. (TU Delft QN/Bauer Group; Kavli institute of nanoscience Delft); Liu, Chuanpu (Beihang University); Liu, Tao (Colorado State University); Madami, Marco (University of Perugia); Shen, Ka (Beijing Normal University); Zhang, J (Beihang University); Blanter, Y.M. (TU Delft QN/Blanter Group; Kavli institute of nanoscience Delft); Bauer, G.E. (TU Delft QN/Bauer Group; Kavli institute of nanoscience Delft; Tohoku University; Rijksuniversiteit Groningen)","","2019","Magnon spintronics is a prosperous field that promises beyond-CMOS technology based on elementary excitations of the magnetic order that act as information carriers for future computational architectures. Unidirectional propagation of spin waves is key to the realization of magnonic logic devices. However, previous efforts to enhance the magnetostatic surface spin wave nonreciprocity did not realize (let alone control) purely unidirectional propagation. Here we experimentally demonstrate excitation of unidirectional exchange spin waves by a nanoscale magnetic grating consisting of Co nanowires fabricated on an ultrathin yttrium iron garnet film. We explain and model the nearly perfect unidirectional excitation by the chirality of the magneto-dipolar interactions between the Kittel mode of the nanowires and the exchange spin waves of the film. Reversal of the magnetic configurations of film and nanowire array from parallel to antiparallel changes the direction of the excited spin waves. Our results raise the prospect of a chiral magnonic logic without the need to involve fragile surface states.","magnetic interaction; spin dynamics; spin waves; spintronics","en","journal article","","","","","","","","","","","QN/Bauer Group","","",""
"uuid:74d8487d-dee0-4448-9ed0-cedcdffc701c","http://resolver.tudelft.nl/uuid:74d8487d-dee0-4448-9ed0-cedcdffc701c","Deriving vegetation drag coefficients in combined wave-current flows by calibration and direct measurement methods","Chen, Hui (Sun Yat-sen University; State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology; Guangdong Province Engineering Research Center of Coasts); Ni, Yan (Shanghai Waterway Engineering Design and Consulting Co., Ltd.); Li, Yulong (Sun Yat-sen University; State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology; Guangdong Province Engineering Research Center of Coasts); Liu, Feng (Sun Yat-sen University; State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology; Guangdong Province Engineering Research Center of Coasts); Ou, Suying (Sun Yat-sen University; State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology; Guangdong Province Engineering Research Center of Coasts); Su, Min (Sun Yat-sen University; State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology; Guangdong Province Engineering Research Center of Coasts); Peng, Yisheng (Sun Yat-sen University); Hu, Zhan (Sun Yat-sen University; State and Local Joint Engineering Laboratory of Estuarine Hydraulic Technology; Guangdong Province Engineering Research Center of Coasts); Uijttewaal, W.S.J. (TU Delft Environmental Fluid Mechanics); Suzuki, T. (TU Delft Environmental Fluid Mechanics; Flanders Hydraulics Research)","","2018","Coastal vegetation is efficient in damping incident waves even in storm events, thus providing valuable protections to coastal communities. However, large uncertainties lie in determining vegetation drag coefficients (CD), which are directly related to the wave damping capacity of a certain vegetated area. One major uncertainty is related to the different methods used in deriving CD. Currently, two methods are available, i.e. the conventional calibration approach and the new direct measurement approach. Comparative studies of these two methods are lacking to reveal their respective strengths and reduce the uncertainty. Additional uncertainty stems from the dependence of CD on flow conditions (i.e. wave-only or wave-current) and indicative parameters, i.e. Reynolds number (Re) and Keulegan-Carpenter number (KC). Recent studies have obtained CD-Re relations for combined wave-current flows, whereas CD-KC relations in such flow condition remain unexplored. Thus, this study conducts a thorough comparison between two existing methods and explores the CD-KC relations in combined wave-current flows. By a unique revisiting procedure, we show that CD derived by the direct measurement approach have a better overall performance in reproducing both acting force and the resulting wave dissipation. Therefore, a generic CD-KC relation for both wave-only and wave-current flows is proposed using direct measurement approach. Finally, a detailed comparison of these two approaches are given. The comprehensive method comparison and the obtained new CD-KC relation may lead to improved understanding and modelling of wave-vegetation interaction.","Drag coefficient; Flume experiment; Keulegan-Carpenter number; Vegetation; Wave dissipation; Wave-current interaction","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-04-16","","","Environmental Fluid Mechanics","","",""
"uuid:3e9873dd-a6d6-49d6-8fc5-57c0ab99acae","http://resolver.tudelft.nl/uuid:3e9873dd-a6d6-49d6-8fc5-57c0ab99acae","Current and future trends in topology optimization for additive manufacturing","Liu, Jikai (University of Pittsburgh); Gaynor, Andrew T. (U.S. Army Research Laboratory); Chen, Shikui (State University of New York); Kang, Zhan (Dalian University of Technology); Suresh, Krishnan (University of Wisconsin-Madison); Takezawa, Akihiro (Hiroshima University); Li, Lei (University of Notre Dame); Kato, Junji (Tohoku University); Tang, Jinyuan (Central South University); Wang, C.C. (TU Delft Materials and Manufacturing); Cheng, Lin (University of Pittsburgh); Liang, Xuan (University of Pittsburgh); To, Albert. C. (University of Pittsburgh)","","2018","Manufacturing-oriented topology optimization has been extensively studied the past two decades, in particular for the conventional manufacturing methods, for example, machining and injection molding or casting. Both design and manufacturing engineers have benefited from these efforts because of the close-to-optimal and friendly-to-manufacture design solutions. Recently, additive manufacturing (AM) has received significant attention from both academia and industry. AM is characterized by producing geometrically complex components layer-by-layer, and greatly reduces the geometric complexity restrictions imposed on topology optimization by conventional manufacturing. In other words, AM can make near-full use of the freeform structural evolution of topology optimization. Even so, new rules and restrictions emerge due to the diverse and intricate AM processes, which should be carefully addressed when developing the AM-specific topology optimization algorithms. Therefore, the motivation of this perspective paper is to summarize the state-of-art topology optimization methods for a variety of AM topics. At the same time, this paper also expresses the authors’ perspectives on the challenges and opportunities in these topics. The hope is to inspire both researchers and engineers to meet these challenges with innovative solutions.","Additive manufacturing; Lattice infill; Material feature; Multi-material; Post-treatment; Support structure; Topology optimization; Uncertainty","en","journal article","","","","","","Accepted author manuscript","","2019-06-30","","","Materials and Manufacturing","","",""
"uuid:6f681b7d-4b4d-476e-8e48-e6553ed6728a","http://resolver.tudelft.nl/uuid:6f681b7d-4b4d-476e-8e48-e6553ed6728a","Automatic Defect Detection of Fasteners on the Catenary Support Device Using Deep Convolutional Neural Network","Chen, Junwen (Southwest Jiaotong University); Liu, Zhigang (Southwest Jiaotong University); Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Han, Zhiwei (Southwest Jiaotong University)","","2018","The excitation and vibration triggered by the long-term operation of railway vehicles inevitably result in defective states of catenary support devices. With the massive construction of high-speed electrified railways, automatic defect detection of diverse and plentiful fasteners on the catenary support device is of great significance for operation safety and cost reduction. Nowadays, the catenary support devices are periodically captured by the cameras mounted on the inspection vehicles during the night, but the inspection still mostly relies on human visual interpretation. To reduce the human involvement, this paper proposes a novel vision-based method that applies the deep convolutional neural networks (DCNNs) in the defect detection of the fasteners. Our system cascades three DCNN-based detection stages in a coarse-to-fine manner, including two detectors to sequentially localize the cantilever joints and their fasteners and a classifier to diagnose the fasteners' defects. Extensive experiments and comparisons of the defect detection of catenary support devices along the Wuhan-Guangzhou high-speed railway line indicate that the system can achieve a high detection rate with good adaptation and robustness in complex environments.","Automatic defect detection; Cameras; catenary support device; Computer architecture; deep convolutional neural network (DCNN); Detectors; fastener; Fasteners; Feature extraction; high-speed railway.; Rail transportation","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:7f313ebf-1702-4afb-84f1-da870e9db5c8","http://resolver.tudelft.nl/uuid:7f313ebf-1702-4afb-84f1-da870e9db5c8","Modeling of information diffusion on social networks with applications to WeChat","Liu, L. (TU Delft Multimedia Computing; National University of Defense Technology); Qu, B. (TU Delft Multimedia Computing); Chen, Bin (National University of Defense Technology); Hanjalic, A. (TU Delft Intelligent Systems); Wang, H. (TU Delft Multimedia Computing)","","2018","Traces of user activities recorded in online social networks open new possibilities to systematically understand the information diffusion process on social networks. From the online social network WeChat, we collected a large number of information cascade trees, each of which tells the spreading trajectory of a message/information such as which user creates the information and which users view or forward the information shared by which neighbors. In this work, we propose two heterogeneous non-linear models, one for the topologies of the information cascade trees and the other for the stochastic process of information diffusion on a social network. Both models are validated by the WeChat data in reproducing and explaining key features of cascade trees.
Specifically, we apply the Random Recursive Tree (RRT) to model the growth of cascade trees. The RRT model could capture key features, i.e. the average path length and degree variance of a cascade tree in relation to the number of nodes (size) of the tree. Its single identified parameter quantifies the relative depth or broadness of the cascade trees and indicates that information propagates via a star-like broadcasting or viral-like hop by hop spreading. The RRT model explains the appearance of hubs, thus a possibly smaller average path length as the cascade size increases, as observed in WeChat. We further propose the stochastic Susceptible View Forward Removed (SVFR) model to depict the dynamic user behavior including creating, viewing, forwarding and ignoring a message on a given social network. Beside the average path length and degree variance of the cascade trees in relation to their sizes, the SVFR model could further explain the power-law cascade size distribution in WeChat and unravel that a user with a large number of friends may actually have a smaller probability to read a message (s)he receives due to limited attention.","Information cascade; Stochastic model; Social networks; WeChat; Random recursive tree","en","journal article","","","","","","Accepted author manuscript","","2020-02-06","","Intelligent Systems","Multimedia Computing","","",""
"uuid:28c63d14-06fa-431c-9d91-b43fd435831d","http://resolver.tudelft.nl/uuid:28c63d14-06fa-431c-9d91-b43fd435831d","Tabu-Based Large Neighbourhood Search for Time-Dependent Multi-Orbit Agile Satellite Scheduling","He, L. (TU Delft Algorithmics; National University of Defense Technology); de Weerdt, M.M. (TU Delft Algorithmics); Yorke-Smith, N. (TU Delft Algorithmics); Liu, Xiaolu (National University of Defense Technology); Chen, Yingwu (National University of Defense Technology)","Bernardini, S. (editor); Parkinson, S, (editor); Talamadupula, K. (editor)","2018","Agile Earth observation satellite (AEOS) scheduling is complex, due to long visible time windows and time-dependent transitions between observations. We introduce a generic approach suited for scheduling problems characterised by time-dependency and/or sequence-dependency. Our approach is a novel hybridization of adaptive large neighbourhood search (ALNS) and tabu search. We further introduce partial sequence dominance and insertion position ordering operators to the ALNS. Extensive computational results on a real-world multi-orbit AEOS observation scheduling benchmark show that the hybrid ALNS robustly outperforms an improved mixed integer programming model and two recent state-of-the-art metaheuristic methods. The proposed method increases solution quality by more than 10% and reduces calculation time by more than 70% on average","","en","conference paper","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2019-07-01","","","Algorithmics","","",""
"uuid:66ab4ea4-2b2d-48f2-a83a-fc11c61c66c1","http://resolver.tudelft.nl/uuid:66ab4ea4-2b2d-48f2-a83a-fc11c61c66c1","The effects of graphene stacking on the performance of methane sensor: A first-principles study on the adsorption, band gap and doping of graphene","Yang, Ning (Guilin University of Electronic Technology); Yang, Daoguo (Guilin University of Electronic Technology); Zhang, Kouchi (TU Delft Electronic Components, Technology and Materials; Guilin University of Electronic Technology); Chen, Liangbiao (Lamar University); Liu, Dongjing (Guilin University of Electronic Technology); Cai, Miao (Guilin University of Electronic Technology); Fan, Xuejun (Lamar University)","","2018","The effects of graphene stacking are investigated by comparing the results of methane adsorption energy, electronic performance, and the doping feasibility of five dopants (i.e., B, N, Al, Si, and P) via first-principles theory. Both zigzag and armchair graphenes are considered. It is found that the zigzag graphene with Bernal stacking has the largest adsorption energy on methane, while the armchair graphene with Order stacking is opposite. In addition, both the Order and Bernal stacked graphenes possess a positive linear relationship between adsorption energy and layer number. Furthermore, they always have larger adsorption energy in zigzag graphene. For electronic properties, the results show that the stacking effects on band gap are significant, but it does not cause big changes to band structure and density of states. In the comparison of distance, the average interlamellar spacing of the Order stacked graphene is the largest. Moreover, the adsorption effect is the result of the interactions between graphene and methane combined with the change of graphene’s structure. Lastly, the armchair graphene with Order stacking possesses the lowest formation energy in these five dopants. It could be the best choice for doping to improve the methane adsorption.","Adsorption; Doping; Electronic performance; First-principles theory; Graphene stacking; Methane sensor","en","journal article","","","","","","","","","","","Electronic Components, Technology and Materials","","",""
"uuid:ed3df416-e469-4ebc-b2e3-f4ac2c3e4788","http://resolver.tudelft.nl/uuid:ed3df416-e469-4ebc-b2e3-f4ac2c3e4788","Planetary gears feature extraction and fault diagnosis method based on VMD and CNN","Liu, C. (China University of Mining and Technology); Cheng, Gang (China University of Mining and Technology); Chen, Xihui (Hohai University); Pang, Y. (TU Delft Transport Engineering and Logistics)","","2018","Given local weak feature information, a novel feature extraction and fault diagnosis method for planetary gears based on variational mode decomposition (VMD), singular value decomposition (SVD), and convolutional neural network (CNN) is proposed. VMD was used to decompose the original vibration signal to mode components. The mode matrix was partitioned into a number of submatrices and local feature information contained in each submatrix was extracted as a singular value vector using SVD. The singular value vector matrix corresponding to the current fault state was constructed according to the location of each submatrix. Finally, by training a CNN using singular value vector matrices as inputs, planetary gear fault state identification and classification was achieved. The experimental results confirm that the proposed method can successfully extract local weak feature information and accurately identify different faults. The singular value vector matrices of different fault states have a distinct difference in element size and waveform. The VMD-based partition extraction method is better than ensemble empirical mode decomposition (EEMD), resulting in a higher CNN total recognition rate of 100% with fewer training times (14 times). Further analysis demonstrated that the method can also be applied to the degradation recognition of planetary gears. Thus, the proposed method is an effective feature extraction and fault diagnosis technique for planetary gears.","CNN; Degradation; Feature extraction; Partition; Planetary gear; SVD; VMD","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:305ee0fd-621d-4f72-9066-dc2e243f2702","http://resolver.tudelft.nl/uuid:305ee0fd-621d-4f72-9066-dc2e243f2702","Comparison of levelized cost of energy of superconducting direct drive generators for a 10-MW offshore wind turbine","Abrahamsen, Asger Bech (Technical University of Denmark); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Magnusson, Niklas (SINTEF Energy Resarch); Thomas, Arwyn (Siemens Wind Power); Azar, Ziad (Siemens Wind Power); Stehouwer, Ewoud (DNV-GL); Hendriks, Ben (Knowledge Centre WMC); Van Zinderen, Gerrit-Jan (DNV GL); Deng, Fujin (Aalborg University); Chen, Zhe (Aalborg University); Karwatzki, Dennis (Leibniz Universität); Mertens, Axel (Leibniz Universität); Parker, Max (University of Strathclyde); Finney, Stephen (University of Edinburgh); Polinder, H. (TU Delft Transport Engineering and Logistics)","","2018","A method for comparing the levelized cost of energy (LCoE) of different superconducting drive trains is introduced. The properties of a 10-MW MgB2 superconducting direct-drive generator and the cost break down of the nacelle components are presented and scaled up to a turbine with a rotor diameter of up to 280 m. The partial load efficiency of the generator is evaluated for a constant cooling power of 0, 50, and 100 kW, and the annual energy production is used to determine the impact on the LCoE.","Generators; levelized cost of energy (LCoE); superconductor; wind energy","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses theDutch legislation to make this work public.","","2018-08-28","","","DC systems, Energy conversion & Storage","","",""
"uuid:1c855809-d1e6-46aa-8086-bf055c67eea9","http://resolver.tudelft.nl/uuid:1c855809-d1e6-46aa-8086-bf055c67eea9","In-situ STEM imaging of growth and phase change of individual CuAlX precipitates in Al alloy","Liu, C. (TU Delft QN/High Resolution Electron Microscopy; Hunan University; Kavli institute of nanoscience Delft); Malladi, S.R.K. (TU Delft QN/Zandbergen Lab; Indian Institute of Technology Hyderabad; Kavli institute of nanoscience Delft); Xu, Q. (TU Delft QN/Zandbergen Lab; DENSsolutions; Kavli institute of nanoscience Delft); Chen, Jianghua (Hunan University); Tichelaar, F.D. (TU Delft QN/Zandbergen Lab; Kavli institute of nanoscience Delft); Zhuge, Xiaodong (Centrum Wiskunde & Informatica (CWI)); Zandbergen, H.W. (TU Delft QN/Zandbergen Lab; Kavli institute of nanoscience Delft)","","2017","Age-hardening in Al alloys has been used for over a century to improve its mechanical properties. However, the lack of direct observation limits our understanding of the dynamic nature of the evolution of nanoprecipitates during age-hardening. Using in-situ (scanning) transmission electron microscopy (S/TEM) while heating an Al-Cu alloy, we were able to follow the growth of individual nanoprecipitates at atomic scale. The heat treatments carried out at 140, 160, 180 and 200 °C reveal a temperature dependence on the kinetics of precipitation and three kinds of interactions of nano-precipitates. These are precipitate-matrix, precipitate-dislocation, and precipitate-precipitate interactions. The diffusion of Cu and Al during these interactions, results in diffusion-controlled individual precipitate growth, an accelerated growth when interactions with dislocations occur and a size dependent precipitate-precipitate interaction: growth and shrinkage. Precipitates can grow and shrink at opposite ends at the same time resulting in an effective displacement. Furthermore, the evolution of the crystal structure within an individual nanoprecipiate, specifically the mechanism of formation of the strengthening phase, θ′, during heat-treatment is elucidated by following the same precipitate through its intermediate stages for the first time using in-situ S/TEM studies.","","en","journal article","","","","","","","","","","","QN/High Resolution Electron Microscopy","","",""
"uuid:3420c6e4-5e1a-4ae8-b1a1-54481cffee6e","http://resolver.tudelft.nl/uuid:3420c6e4-5e1a-4ae8-b1a1-54481cffee6e","Form-finding and construction of ice composite shell structures","Wu, Yue (Harbin Institute of Technology); Liu, Xiuming (Harbin Institute of Technology); Li, Q. (TU Delft Structural Design & Mechanics); Chen, Boxuan (Harbin Institute of Technology); Luo, Peng (Harbin Institute of Technology); Pronk, Arno (Eindhoven University of Technology); Mergny, Elke (Université de Liège)","Bögle, Annette (editor); Grohmann, Manfred (editor)","2017","By using inflatable moulds and then spraying cellulose-water mixture, one ice dome and two ice towers were built in Harbin in December 2016. During the whole process, form-finding of the inflatable moulds as well as the construction of these ice composite shell structures are very important for the final results.
The mould for the ice dome structure was a result of the manipulation of a synclastic membrane with a rope net. The mould for the ice tower structure consisted of some anticlastic surfaces. Form-finding of the inflatable moulds was conducted by the parametric tool “EasyForm” which is a self-programed plug-in in Grasshopper based on Vector Form Intrinsic Finite Element method.
In a low-temperature work environment (-10 ℃ and below), the ice shell structures were constructed on the inflatable moulds. The cellulose-water mixture was sprayed in thin layers continuously and uniformly in order to make the surface of a shell of cellulose-reinforced ice. The construction process is introduced detailedly in this paper.","Ice composite shell; form-finding; Vector Form Intrinsic Finite Element; construction; inflatable mould; cellulose-reinforced ice","en","conference paper","","","","","","","","","","","Structural Design & Mechanics","","",""
"uuid:27f67e03-f54c-4398-8abb-834f440cdf44","http://resolver.tudelft.nl/uuid:27f67e03-f54c-4398-8abb-834f440cdf44","Organic Solvent-Tolerant Marine Microorganisms as Catalysts for Kinetic Resolution of Cyclic β-Hydroxy Ketones","Chen, B. (TU Delft BT/Biocatalysis; Sun Yat-sen University); Liu, Hui (Sun Yat-sen University); Zeferino Ribeiro De Souza, F. (TU Delft BT/Biocatalysis; Universidade de São Paulo); Liu, Lan (Sun Yat-sen University)","","2017","Chiral cyclic β-hydroxy ketones represent key motifs in the production of natural products of biological interest. Although the molecules are structurally simple, they require cumbersome synthetic steps to get access to them and their synthesis remains a challenge in organic chemistry. In this report, we describe a straightforward approach to enantiomerically enriched (R)- and (S)-3-hydroxycyclopentanone 2a, (R)- and (S)-3-hydroxycyclohexanone 2b, and (R)- and (S)-3-hydroxycycloheptanone 2c involving a transesterification resolution of the racemates using whole cells of marine microorganisms as catalysts and vinyl acetate the acyl donor and solvent. Twenty-six strains from a wide collection of isolates from marine sediments were screened, and seven strains were found to markedly catalyze the resolution in an asymmetric fashion. Using the strain Serratia sp., (R)-2a was isolated in 27% yield with 92% ee and (S)-2a in 65% yield with 43% ee, corresponding to an E-value of 37; (R)-2b was isolated in 25% yield with 91% ee and (S)-2b in 67% yield with 39% ee, corresponding to an E-value of 40; and (R)-2c was isolated in 30% yield with 96% ee and (S)-2c in 63% yield with 63% ee, corresponding to an E-value of 75.","Biocatalysis; Cyclic β-hydroxy ketones; E-value; Kinetic resolution; Marine microorganisms","en","journal article","","","","","","Accepted Author Manuscript","","2018-06-13","","","BT/Biocatalysis","","",""
"uuid:9437c6cd-f33f-4317-9020-82f05da5f1b6","http://resolver.tudelft.nl/uuid:9437c6cd-f33f-4317-9020-82f05da5f1b6","Intelligent condition monitoring of railway catenary systems: A Bayesian Network approach","Wang, H. (TU Delft Railway Engineering); Nunez, Alfredo (TU Delft Railway Engineering); Dollevoet, R.P.B.J. (TU Delft Railway Engineering); Liu, Zhigang (Southwest Jiaotong University); Chen, Junwen (Southwest Jiaotong University)","Spiryagin, Maksym (editor); Gordon, Timothy (editor); Cole, Colin (editor); McSweeney, Tim (editor)","2017","This study proposes a Bayesian network (BN) dedicated for the intelligent condition monitoring of railway catenary systems. It combines five types of measurements related to catenary condition, namely the contact wire stagger, contact wire height, pantograph head displacement, pantograph head vertical acceleration and pantograph-catenary contact force, as inputs
based on their physical meanings and correlations. It outputs an integrated indicator of catenary condition level. The BN parameters are learned from historical measurement data. Preliminary results shows the applicable ability of the BN to integrate multiple types of parameter while make sense of the output to facilitate maintenance decision making.","","en","conference paper","","","","","","","","","","","Railway Engineering","","",""
"uuid:c9c93b5e-64aa-4889-b5b3-ebe012e2b8f1","http://resolver.tudelft.nl/uuid:c9c93b5e-64aa-4889-b5b3-ebe012e2b8f1","Comparison of Levelized Cost of Energy of a 10 MW superconducting and magnetic pseudo direct drive generator targeted for the INNWIND.EU reference turbine","Abrahamsen, Asger Bech (Technical University of Denmark); Liu, D. (TU Delft DC systems, Energy conversion & Storage); Magnusson, Niklas (SINTEF); Thomas, A (Siemens Wind Power); Z., Azar (Siemens Wind Power); Stehouwer, Ewoud (DNV-GL); Hendriks, E (Knowledge Centre WMC); Penzkofer, A. (University of Sheffield); Atallah, K (University of Sheffield); Dragan, R.R. (Magnomatics); .Clark, R.E. (Magnomatics); Deng, F. (Aalborg University); Chen, Z (Aalborg University); Karwatzki, D. (Leibniz Universität); Mertens, A. (Leibniz Universität); Parker, M. (University of Strathclyde); Finney, SJ (University of Strathclyde); Polinder, H.","","2017","Innovative drive trains targeted at 10-20 MW offshore turbines are investigated in the INNWIND.EU project in order to determine the impact on the Levelized Cost of Energy (LCoE) resulting when installed in the ,North sea at 50 m of water [1]. The two main technologies studied are superconducting direct drive (SCDD)[2] and the magnetic pseudo direct drive (PDD) [3] generators, which are both capable to providing compact drive trains with low weight and a small number of moving parts compared to a gearbox based drive train (see figure 1a). Superconducting field coils are used to provide the torque in the direct drive generators, where the armature windings are based on conventional copper wire and magnetic steel laminates operated at ambient temperature. Magnetic pseudo direct drive generators consist of a magnetic gearbox made of an inner free rotor (rotating at a geared up speed to the blade input) and an intermediate drive rotor inserted into an outer static armature winding, where the electricity is harvested.","","en","abstract","","","","","","","","","","","DC systems, Energy conversion & Storage","","",""
"uuid:430af4d8-5737-45b1-ac0b-5baa96a4de98","http://resolver.tudelft.nl/uuid:430af4d8-5737-45b1-ac0b-5baa96a4de98","Experimental research on the determination of the coefficient of sliding wear under iron ore handling conditions","Chen, G. (TU Delft Transport Engineering and Logistics); Liu, Y. (TU Delft Micro and Nano Engineering); Lodewijks, G. (TU Delft Transport Engineering and Logistics); Schott, D.L. (TU Delft Transport Engineering and Logistics)","","2017","The handling of iron ore bulk solids maintains an increasing trend due to economic development. Because iron ore particles have hard composites and irregular shapes, the bulk solids handling equipment surface can suffer from severe sliding wear. Prediction of equipment surface wear volume is beneficial to the efficient maintenance of worn areas. Archard’s equation provides a theoretical solution to predict wear volume. To use Archard’s equation, the coefficient of sliding wear must be determined. To our best knowledge, the coefficient of sliding wear for iron ore handling conditions has not yet been determined. In this research, using a pin-on-disk tribometer, the coefficients of sliding wear for both Sishen particles and mild steel are determined with regard to iron ore handling conditions. Both naturally irregular and spherical shapes of particles are used to estimate average values of wear rate. Moreover, the hardness and inner structures of Sishen particles are examined, which adds the evidence of the interpretation of wear results. It is concluded that the coefficients of sliding wear can vary largely for both Sishen particle and mild steel. The wear rate decreases from transient- to steady-state. The average coefficient of sliding wear is capable of predicting wear with respect to long distances at the steady-state. Two types of sliding friction are distinguished. In addition, it is found that the temperature rise of the friction pairs has negligible influence on wear rate.","Particle wear; Hardness; Pin-on-disk; Sliding friction; Contact temperature","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:3006c9cd-1ddf-4dbc-9dcc-7c30c3c5494b","http://resolver.tudelft.nl/uuid:3006c9cd-1ddf-4dbc-9dcc-7c30c3c5494b","Crack monitoring method for an FRP-strengthened steel structure based on an antenna sensor","Liu, Z. (Wuhan University of Technology); Chen, Kai (Wuhan University of Technology); Li, Z. (TU Delft Transport Engineering and Logistics); Jiang, X. (TU Delft Transport Engineering and Logistics)","","2017","Fiber-reinforced polymer (FRP) has been increasingly applied to steel structures for structural strengthening or crack repair, given its high strength-to-weight ratio and high stiffness-to-weight ratio. Cracks in steel structures are the dominant hidden threats to structural safety. However, it is difficult to monitor structural cracks under FRP coverage and there is little related research. In this paper, a crack monitoring method for an FRP-strengthened steel structure deploying a microstrip antenna sensor is presented. A theoretical model of the dual-substrate antenna sensor with FRP is established and the sensitivity of crack monitoring is studied. The effects of the weak conductivity of carbon fiber reinforced polymers (CFRPs) on the performance of crack monitoring are analyzed via contrast experiments. The effects of FRP thickness on the performance of the antenna sensor are studied. The influence of structural strain on crack detection coupling is studied through strain–crack coupling experiments. The results indicate that the antenna sensor can detect cracks in steel structures covered by FRP (including CFRP). FRP thickness affects the antenna sensor’s performance significantly, while the effects of strain can be ignored. The results provide a new approach for crack monitoring of FRP-strengthened steel structures with extensive application prospects.","Antenna sensor; Cracking; FRP thickness; FRP-strengthened steel structure; Resonant frequency; Sensitivity","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:6dfb7570-0bf9-4bde-abd1-7aa1a021b551","http://resolver.tudelft.nl/uuid:6dfb7570-0bf9-4bde-abd1-7aa1a021b551","Quantification the filling of microcracks due to Autogenous self-healing in cement paste","Chen, J. (TU Delft Materials and Environment); Liu, Xian (Tongji University); Ye, G. (TU Delft Materials and Environment)","Azenha, M. (editor); Gabrijel, I. (editor); Schlicke, D. (editor); Kanstad, T. (editor); Mejlhede Jensen, O. (editor)","2016","Microcracks play vital roles in the prediction of the service life of concrete structure. Because microcracks in concrete structure are the preferential ingression channels for aggressive ions, e.g., chloride, sulphate, etc. However, microcracks have potentials to self-heal autogenously due to the continuous hydration of unhydrated cement, especially when ultra-/ high strength concrete is used. To quantify the autogenous self-healing effects of microcracks in cement paste, our experiment is designed to monitor the self-healing process of microcracks in cement paste continuously by using optical microscope. The healing products are quantified by image analysis with newly implemented software in MATLAB. The results indicate that the microcracks are not filled evenly along the crack length and most healing products are Ca(OH)2, which dissolve partly from the paste matrix and re-nucleate in the microcrack, in addition to its counterpart from the continuous hydration of unhydrated cement. Furthermore, the sample cracked at earlier age shows higher potential to heal, while the sample with smaller crack width experiences greater filling efficiency. The obtained autogenous selfhealing mechanism will be used in the future simulation.","Autogenous self-healing; Microcracks; Service life prediction; Image analysis","en","conference paper","RILEM Publications S.A.R.L.","","","","","","","","","","Materials and Environment","","",""
"uuid:f8a4d4b3-20e7-477b-b513-669c993bb361","http://resolver.tudelft.nl/uuid:f8a4d4b3-20e7-477b-b513-669c993bb361","Wicked but worth it: Student perspectives on socio-hydrology","Levy, MC (External organisation); Garcia, M (External organisation); Blair, P (External organisation); Chen, X (External organisation); Gomes, S.L. (TU Delft Policy Analysis; TU Delft Multi Actor Systems); Gower, DB (External organisation); Grames, J (External organisation); Kuil, L (External organisation); Liu, Y (External organisation); Marston, L (External organisation); McCord, PF (External organisation); Roobavannan, M (External organisation); Zeng, R (External organisation)","","2016","","","en","journal article","","","","","","harvest","","2017-03-06","","Multi Actor Systems","Policy Analysis","","",""
"uuid:c8f1d0d9-30e1-4cac-8ef1-593effe838f0","http://resolver.tudelft.nl/uuid:c8f1d0d9-30e1-4cac-8ef1-593effe838f0","Sustainable Application of a Novel Water Cycle Using Seawater for Toilet Flushing","Liu, Xiaoming (The Hong Kong University of Science and Technology); Dai, Ji (The Hong Kong University of Science and Technology); Wu, Di (The Hong Kong University of Science and Technology); Jiang, Feng (South China Normal University); Chen, Guanghao (The Hong Kong University of Science and Technology); Chui, Ho Kwong (The Hong Kong University of Science and Technology); van Loosdrecht, Mark C.M. (TU Delft BT/Environmental Biotechnology)","","2016","Global water security is a severe issue that threatens human health and well-being. Finding sustainable alternative water resources has become a matter of great urgency. For coastal urban areas, desalinated seawater could serve as a freshwater supply. However, since 20%–30% of the water supply is used for flushing waste from the city, seawater with simple treatment could also partly replace the use of freshwater. In this work, the freshwater saving potential and environmental impacts of the urban water system (water-wastewater closed loop) adopting seawater desalination, seawater for toilet flushing (SWTF), or reclaimed water for toilet flushing (RWTF) are compared with those of a conventional freshwater system, through a life-cycle assessment and sensitivity analysis. The potential applications of these processes are also assessed. The results support the environmental sustainability of the SWTF approach, but its potential application depends on the coastal distance and effective population density of a city. Developed coastal cities with an effective population density exceeding 3000 persons·km−2 and located less than 30 km from the seashore (for the main pipe supplying seawater to the city) would benefit from applying SWTF, regardless of other impact parameters. By further applying the sulfate reduction, autotrophic denitrification, and nitrification integrated (SANI) process for wastewater treatment, the maximum distance from the seashore can be extended to 60 km. Considering that most modern urbanized cities fulfill these criteria, the next generation of water supply systems could consist of a freshwater supply coupled with a seawater supply for sustainable urban development.","Alternative water resources; Life-cycle assessment; SANI; Seawater toilet flushing; Urban water system","en","journal article","","","","","","","","","","","BT/Environmental Biotechnology","","",""
"uuid:f9c5fbb7-d8fe-4682-b270-75dd754f25ee","http://resolver.tudelft.nl/uuid:f9c5fbb7-d8fe-4682-b270-75dd754f25ee","The Influence of a Eutrophic Lake to the River Downstream: Spatiotemporal Algal Composition Changes and the Driving Factors","Yu, Q.; Chen, Y.; Liu, Z.; Van de Giesen, N.C.; Zhu, D.","","2015","Algal blooms have been frequently found at the upper reaches of the Tanglang River, which is downstream from the eutrophic Dianchi Lake. The eutrophic lake upstream is considered to be a potential source of phytoplankton, which contributes to the development of harmful algal blooms in the river downstream and can cause many serious problems for the river ecology. However, few studies focused on these kinds of rivers. Therefore, a field observation and laboratory analysis were conducted in this study. The results showed that the Tanglang River was obviously spatially heterogeneous due to the eutrophic Dianchi Lake upstream. The toxic Microcystis from the Dianchi Lake dominated the phytoplankton at the upper reaches, but these were gradually, rather than immediately, replaced by centric diatoms and chlorococalean green algae in the middle and lower reaches. The results of correlation analysis indicated that the changes in hydrodynamic conditions and underwater light intensity accounted for the spatial variations. The differences in the adaptability of different algae to changing aquatic environments explained the spatial variations of phytoplankton abundance. The dominant algae, most of which was from the Dianchi Lake upstream, determined the characteristics of the total abundance at the Tanglang River.","eutrophication; phytoplankton structures; microcystis; hydrodynamic conditions; turbidity; OA-Fund TU Delft","en","journal article","MDPI","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:ba358001-d778-4d9f-81ec-9a6009fede55","http://resolver.tudelft.nl/uuid:ba358001-d778-4d9f-81ec-9a6009fede55","Progress in multiscale computational electromagnetics in time domain","Tobón, L.; Chen, J.; Lee, J.; Yuan, M.; Zhao, B.; Liu, Q.H.","","2013","Many system-level electromagnetic design problems are multiscale and very challenging to solve. They remain a significant barrier to system design optimization for a foreseeable future. Such multiscale problems often contain three electrical scales, i.e., the fine scale (geometrical feature size much smaller than a wavelength), the coarse scale (geometrical feature size greater than a wavelength), and the intermediate scale between the two extremes. Existing computational tools are based on single methodologies (such as finite element method or finite-difference time-domain method), and are unable to solve large multiscale problems. We will present our recent progress in solving realistic multiscale system-level EM design simulation problems in time domain. The discontinuous Galerkin time domain method is used as the fundamental framework for interfacing multiple scales with finite-element method, spectral element method, and finite difference method. Numerical results demonstrate significant advantages of our multiscale method. A more detail discussion of the method is given in [1].","","en","conference paper","","","","","","","","","","","","","",""
"uuid:bb12200e-b7c1-42f5-b4a4-7a7f13b2a159","http://resolver.tudelft.nl/uuid:bb12200e-b7c1-42f5-b4a4-7a7f13b2a159","Researching interaction guidelines - Mapping playful quality to design interactive products","Chen, Y.C.; Liu, W.","","2012","The interactions in IT supported activities in a Generation Y work context were studied and discussed, which general design guidelines have een revealed. However, further research about practical design guidelines hasn’t been performed. This study aims to serve as supplement of this part based on previous research. By applying contextual interviews of mapping interaction quality and Aesthetic Experience, some phenomena of interaction in work context has been revealed. By using sensitizing toolkits, we extract participants’ latent needs and expectation of future working types. In the end, practical design guidelines for designing playful interactions in work context are drawn. Designers could benefit from the result and utilize the guidelines, prototyping new interactive products. Meanwhile, researchers could apply or modify the sensitizing toolkits or sessions in order to come up with new insights for designing different interaction qualities","aesthetics of interaction, generation Y, interaction; quality, design guidelines","en","conference paper","Chalmers University of Technology","","","","","","","","Industrial Design Engineering","Industrial Design","","","",""
"uuid:1dd1bd48-6c4f-4389-9a4b-36730c4d2610","http://resolver.tudelft.nl/uuid:1dd1bd48-6c4f-4389-9a4b-36730c4d2610","State-of-art of asphalt surfacings on long-spanned orthotropic steel deck in China","Chen, X.; Liu, X.; Qian, Z.; Lei, Z.","","2012","Reliable and durable asphalt surfacing systems still remain to be desired for the long-spanned orthotropic steel bridges as the nationally and internationally reports on distresses in deck pavement. Based on ten-year research works, this paper has presented a brief review and discussion of the Chinese practices and experiences of deck pavement on long-spanned steel bridges, including issues of typical surfacing materials and their properties, main distresses in asphalt surfacing, and the basic characteristics of asphalt surfacing on orthotropic steel bridge decks. It is concluded that the behaviours of deck pavement on oithotropic steel bridge deck under truck load are complex contributed by geometric and material-dependent nonlinearity, coupling the global dynamic effects of the whole bridge systems. More efficient computational techniques are still desirable to couple global effects into local responses, to count the interfacial effects and interaction, and to evaluate the effect of predominant distress of fatigue cracking and de-bonding on the service life of this type of structure.","long-spanned steel bridge; orthotropic steel decks; asphalt surfacing system; local deflection behaviour; composite action; fatigue cracking","en","conference paper","","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","","",""
"uuid:8ae1ea62-8732-4f79-99b5-df10c442a5be","http://resolver.tudelft.nl/uuid:8ae1ea62-8732-4f79-99b5-df10c442a5be","A silicon MEMS structure for characterization of femto-farad-level capacitive sensors with lock-in architecture","Wei, J.; Chen, Z.L.; Liu, Z.W.; Sarro, P.M.","","2010","This paper presents a silicon MEMS capacitive structure to investigate a test methodology for fF-level capacitive sensors’ measurement. The device mimics a capacitive sensor with a changing intermediate layer between the electrodes. A single mask bulk micromachining process is used to fabricate the device, which has a nominal capacitance of 1.2 fF. A high performance measurement setup based on lock-in principle is developed to detect the capacitance variation. The maximum capacitance variation of the fabricated device is 0.31 fF, and the capacitance detection limit is 0.095 aF Hz?1/2.","","en","journal article","Institute of Physics","","","","","","","","Electrical Engineering, Mathematics and Computer Science","DIMES","","","",""
"uuid:5a2b8627-ba8d-4d81-9f4a-7a60ef397b0d","http://resolver.tudelft.nl/uuid:5a2b8627-ba8d-4d81-9f4a-7a60ef397b0d","Evaluation of the longitudinal ultimate strength of various ship hull configurations","Kutt, Lembit M.; Plaszczyk, Christopher M.; Chen, Yung-Kuang; Liu, Donald","","1985","","construction","","conference paper","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Hydromechanics and Structures","","",""