"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:9c9e7446-41fa-4ba4-84c3-03575873e5b0","http://resolver.tudelft.nl/uuid:9c9e7446-41fa-4ba4-84c3-03575873e5b0","Learning-Based Multi-UAV Flocking Control With Limited Visual Field and Instinctive Repulsion","Bai, Chengchao (Harbin Institute of Technology); Yan, Peng (Harbin Institute of Technology); Piao, Haiyin (Northwestern Polytechnical University; SADRI Institute); Pan, W. (TU Delft Robot Dynamics; The University of Manchester); Guo, Jifeng (Harbin Institute of Technology)","","2024","This article explores deep reinforcement learning (DRL) for the flocking control of unmanned aerial vehicle (UAV) swarms. The flocking control policy is trained using a centralized-learning-decentralized-execution (CTDE) paradigm, where a centralized critic network augmented with additional information about the entire UAV swarm is utilized to improve learning efficiency. Instead of learning inter-UAV collision avoidance capabilities, a repulsion function is encoded as an inner-UAV 'instinct.' In addition, the UAVs can obtain the states of other UAVs through onboard sensors in communication-denied environments, and the impact of varying visual fields on flocking control is analyzed. Through extensive simulations, it is shown that the proposed policy with the repulsion function and limited visual field has a success rate of 93.8% in training environments, 85.6% in environments with a high number of UAVs, 91.2% in environments with a high number of obstacles, and 82.2% in environments with dynamic obstacles. Furthermore, the results indicate that the proposed learning-based methods are more suitable than traditional methods in cluttered environments.","Autonomous aerial vehicles; Collision avoidance; Deep reinforcement learning (DRL); flocking control; inter-unmanned aerial vehicle (UAV) collision avoidance; limited visual field; Optimization; Reinforcement learning; Sensors; Training; UAVs; Visualization","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.","","2023-09-08","","","Robot Dynamics","","","" "uuid:2f0f4ac3-66de-45cb-83c0-2a258fdd634a","http://resolver.tudelft.nl/uuid:2f0f4ac3-66de-45cb-83c0-2a258fdd634a","Assessment criteria for inter-organizational collaboration in interconnected infrastructure projects","Rikhtegarnezami, M. (TU Delft Integral Design & Management); de Bruijne, M.L.C. (TU Delft Organisation & Governance); Hertogh, M.J.C.M. (TU Delft Integral Design & Management); Bakker, H.L.M. (TU Delft Integral Design & Management)","","2024","Purpose: Societies depend on interconnected infrastructures that are becoming more complex over the years. Multi-disciplinary knowledge and skills are essential to develop modern infrastructures, requiring close collaboration of various infrastructure owners. To effectively manage and improve inter-organizational collaboration (IOC) in infrastructure construction projects, collaboration status should be assessed continually. This study identifies the assessment criteria, forming the foundation of a tool for assessing the status of IOC in interconnected infrastructure projects.
Design/methodology/approach: A systematic literature study and in-depth semi-structured interviews with practitioners in interconnected infrastructure construction projects in the Netherlands are performed to identify the criteria for assessing the status of IOC in infrastructure construction projects, based on which an assessment tool is developed.
Findings: The identified assessment criteria through the literature and the practitioner’s perspectives results in the designing and development of a collaboration assessment tool. The assessment tool consists of 12 criteria and 36 sub-criteria from three different categories of collaborative capacity: individual, relational, and organizational.
Originality/value: The assessment tool enables practitioners to monitor the status of IOC between infrastructure owners and assists them in making informed decisions to enhance collaboration. The assessment tool provides the opportunity to assess and analyze the status of collaboration based on three categories (i.e., individual, relational, and organizational).","Assessment tool; Construction industry; Horizontal collaboration; Inter-organizational collaboration; Interconnected infrastructure","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:9af93419-2648-4a16-89d8-e34aa863e637","http://resolver.tudelft.nl/uuid:9af93419-2648-4a16-89d8-e34aa863e637","A fast and robust constraint-based online re-optimization approach for automated online adaptive intensity modulated proton therapy in head and neck cancer","Oud, Michelle (Erasmus MC; Holland Particle Therapy Centre); Breedveld, Sebastiaan (Erasmus MC); Rojo-Santiago, Jesús (Erasmus MC; Holland Particle Therapy Centre); Giżyńska, Marta Krystyna (Holland Particle Therapy Centre); Kroesen, Michiel (Erasmus MC); Habraken, S.J.M. (Erasmus MC; Holland Particle Therapy Centre); Perko, Z. (TU Delft RST/Reactor Physics and Nuclear Materials); Heijmen, Ben (Erasmus MC); Hoogeman, M.S. (TU Delft RST/Medical Physics & Technology; Erasmus MC; Holland Particle Therapy Centre)","","2024","Objective. In head-and-neck cancer intensity modulated proton therapy, adaptive radiotherapy is currently restricted to offline re-planning, mitigating the effect of slow changes in patient anatomies. Daily online adaptations can potentially improve dosimetry. Here, a new, fully automated online re-optimization strategy is presented. In a retrospective study, this online re-optimization approach was compared to our trigger-based offline re-planning (offlineTB re-planning) schedule, including extensive robustness analyses. Approach. The online re-optimization method employs automated multi-criterial re-optimization, using robust optimization with 1 mm setup-robustness settings (in contrast to 3 mm for offlineTB re-planning). Hard planning constraints and spot addition are used to enforce adequate target coverage, avoid prohibitively large maximum doses and minimize organ-at-risk doses. For 67 repeat-CTs from 15 patients, fraction doses of the two strategies were compared for the CTVs and organs-at-risk. Per repeat-CT, 10.000 fractions with different setup and range robustness settings were simulated using polynomial chaos expansion for fast and accurate dose calculations. Main results. For 14/67 repeat-CTs, offlineTB re-planning resulted in <50% probability of D98% ≥ 95% of the prescribed dose (Dpres) in one or both CTVs, which never happened with online re-optimization. With offlineTB re-planning, eight repeat-CTs had zero probability of obtaining D98% ≥ 95%Dpres for CTV7000, while the minimum probability with online re-optimization was 81%. Risks of xerostomia and dysphagia grade ≥ II were reduced by 3.5 ± 1.7 and 3.9 ± 2.8 percentage point [mean ± SD] (p < 10−5 for both). In online re-optimization, adjustment of spot configuration followed by spot-intensity re-optimization took 3.4 min on average. Significance. The fast online re-optimization strategy always prevented substantial losses of target coverage caused by day-to-day anatomical variations, as opposed to the clinical trigger-based offline re-planning schedule. On top of this, online re-optimization could be performed with smaller setup robustness settings, contributing to improved organs-at-risk sparing.","intensity modulated proton therapy (IMPT); daily online adaptive radiotherapy using dose restoration; head-and-neck cancer; inter-fraction anatomy variation; automated treatment planning","en","journal article","","","","","","","","","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:a5637eae-904b-4a52-a5fd-c5b3762a62fe","http://resolver.tudelft.nl/uuid:a5637eae-904b-4a52-a5fd-c5b3762a62fe","Factors Influencing Business-to-Government Information-Sharing Arrangements: Understanding system architectures and governance structures in information-sharing","Praditya, D.","Janssen, M.F.W.H.A. (promotor); Bharosa, Nitesh (promotor); Delft University of Technology (degree granting institution)","2023","The urgent need to improve public services and increase the adoption of cutting-edge technology in public organizations has promoted and encouraged collaboration between private and public organizations, thus allowing for more information to be shared between both parties. However, many issues arise that hinder the implementation of information-sharing, ranging from a lack of information quality to organizational resistance to sharing information due to uncertainty of the benefits or a lack of top-level management support. To address these challenges and to realize the benefits of business-to-government (B2G) information-sharing, it is necessary to understand how to arrange B2G information-sharing.
This research contributes scientifically and practically to the B2G information-sharing domain by proposing the concept of information-sharing arrangements through system architecture and governance structure lenses and analyzing the factors that influence such arrangements. The discussions include when to use a centralized topology or in what situations decentralized information-sharing is preferred, why there are mandatory and voluntary information-sharing, and in which situation consensus-based or hierarchical-based decision-making are needed. In addition, the role of trust among sharing partners, technological requirements, organizational readiness, and other factors identified as potentially influencing information-sharing arrangements were also discussed.
By understanding the arrangements and factors influencing them, B2G information-sharing actors can select the most suitable arrangements and potentially increase the adoption of information-sharing initiatives.","information-sharing; system arrangements; system architecture; governance structure; Inter-organizational system","en","doctoral thesis","","978-94-6384-422-2","","","","","","","","","Information and Communication Technology","","",""
"uuid:dddba2e8-85f7-4123-a609-6548f83976fa","http://resolver.tudelft.nl/uuid:dddba2e8-85f7-4123-a609-6548f83976fa","Wave Energy in Brittany (France)—Resource Assessment and WEC Performances","Guillou, Nicolas (Cerema: Center for Studies and Expertise on Risks, the Environment, Mobility and Planning); Lavidas, G. (TU Delft Offshore Engineering); Kamranzad, Bahareh (University of Strathclyde)","","2023","Refined numerical wave energy resource assessments are required to reduce uncertainties in the evaluation of available power and energy production. However, to restrict the computational cost, a great part of wave hindcast simulations cover a limited time range (below ten years) or rely on coarse spatial resolutions while routinely ignoring tide-induced modulations in wave conditions. Complementing resource assessments conducted in the North-West European shelf seas, we here exploited a 27-year hindcast database (1994–2020) set up at a spatial resolution of 200 m along the coast of France and integrating the effects of tidal currents on waves. This evaluation was conducted in three water depths from offshore to nearshore (60, 40 and 20 m) around Brittany, one of the most energetic regions along the coast of France. We investigated the performances of a series of thirteen state-of-the-art wave energy converters with respect to installation depth range. Beyond confirming the interest of western Brittany in energy exploitation, the results exhibited the first ranking between devices, thus promoting the interests of Oceantec in offshore waters (60 m), Wave Dragon in intermediate waters (40 m), and Oyster and WaveStar C6 in shallow waters (20 m).","inter-annual and inter-seasonal variability; wave climate; wave energy converters; capacity analysis; efficiency index; hindcast database; wave and current interactions; power matrix","en","journal article","","","","","","","","","","","Offshore Engineering","","",""
"uuid:cbad79df-846c-4153-a6eb-8cdacfc73b39","http://resolver.tudelft.nl/uuid:cbad79df-846c-4153-a6eb-8cdacfc73b39","Micromechanical Models for FDM 3D-Printed Polymers: A Review","Bol, R.J.M. (TU Delft Materials and Environment); Šavija, B. (TU Delft Materials and Environment)","","2023","Due to its large number of advantages compared to traditional subtractive manufacturing techniques, additive manufacturing (AM) has gained increasing attention and popularity. Among the most common AM techniques is fused filament fabrication (FFF), usually referred to by its trademarked name: fused deposition modeling (FDM). This is the most efficient technique for manufacturing physical three-dimensional thermoplastics, such that FDM machines are nowadays the most common. Regardless of the 3D-printing methodology, AM techniques involve layer-by-layer deposition. Generally, this layer-wise process introduces anisotropy into the produced parts. The manufacturing procedure creates parts possessing heterogeneities at the micro (usually up to 1 mm) and meso (mm to cm) length scales, such as voids and pores, whose size, shape, and spatial distribution are mainly influenced by the so-called printing process parameters. Therefore, it is crucial to investigate their influence on the mechanical properties of FDM 3D-printed parts. This review starts with the identification of the printing process parameters that are considered to affect the micromechanical composition of FDM 3D-printed polymers. In what follows, their (negative) influence is attributed to characteristic mechanical properties. The remainder of this work reviews the state of the art in geometrical, numerical, and experimental analyses of FDM-printed parts. Finally, conclusions are drawn for each of the aforementioned analyses in view of microstructural modeling.","fused deposition modeling (FDM); additive manufacturing (AM); printing process parameters; mechanical anisotropy; inter-layer bond; intra-layer bond","en","review","","","","","","","","","","","Materials and Environment","","",""
"uuid:22142e58-d187-4279-8817-f5ca120ee0a4","http://resolver.tudelft.nl/uuid:22142e58-d187-4279-8817-f5ca120ee0a4","Self-Supervised PPG Representation Learning Shows High Inter-Subject Variability","Ghorbani, R. (TU Delft Pattern Recognition and Bioinformatics); Reinders, M.J.T. (TU Delft Pattern Recognition and Bioinformatics); Tax, D.M.J. (TU Delft Pattern Recognition and Bioinformatics)","","2023","With the progress of sensor technology in wearables, the collection and analysis of PPG signals are gaining more interest. Using Machine Learning, the cardiac rhythm corresponding to PPG signals can be used to predict different tasks such as activity recognition, sleep stage detection, or more general health status. However, supervised learning is often limited by the amount of available labeled data, which is typically expensive to obtain. To address this problem, we propose a Self-Supervised Learning (SSL) method with a pretext task of signal reconstruction to learn an informative generalized PPG representation. The performance of the proposed SSL framework is compared with two fully supervised baselines. The results show that in a very limited label data setting (10 samples per class or less), using SSL is beneficial, and a simple classifier trained on SSL-learned representations outperforms fully supervised deep neural networks. However, the results reveal that the SSL-learned representations are too focused on encoding the subjects. Unfortunately, there is high inter-subject variability in the SSL-learned representations, which makes working with this data more challenging when labeled data is scarce. The high inter-subject variability suggests that there is still room for improvements in learning representations. In general, the results suggest that SSL may pave the way for the broader use of machine learning models on PPG data in label-scarce regimes.","Autoencoder; Human Activity Recognition; Inter-Subject Variability; PPG Signal; Representation Learning; Self-Supervised Learning","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:0c56b2c3-0e1d-43d7-a4a4-a1985fbe6f11","http://resolver.tudelft.nl/uuid:0c56b2c3-0e1d-43d7-a4a4-a1985fbe6f11","A bidding mechanism for maintenance of generation units considering inter-ISO power exchange","Fu, J. (TU Delft Team Bart De Schutter); Nunez, Alfredo (TU Delft Railway Engineering); De Schutter, B.H.K. (TU Delft Team Bart De Schutter)","","2023","To ensure the reliability of power systems, the independent system operator (ISO) manages the planning process of the maintenance of generation units for generation companies (GENCOs). This paper focuses on a widely studied two-layer long-term predictive maintenance decision making framework in a deregulated environment. In the first layer the ISO-wide maintenance schedule is optimized for the GENCOs, targeting minimal total maintenance cost and degradation statuses. In the second layer, a bidding mechanism is designed for GENCOs who are not satisfied with the time slots scheduled by the first layer, so that they can bid for their preferred time slots. A novel bidding mechanism for the host ISO (i.e., the ISO that manages the maintenance planning process) is proposed, called interchangeable bidding mechanism for maintenance (IBMM). In this mechanism, the GENCOs of the host ISO can use their bid price to purchase the supportive energy from the GENCOs of the neighbor ISOs. Furthermore, they also can pay a penalty fee for reducing the amount of energy transmitted from the host ISO to the neighbor ISO with respect to what has been stipulated in the long-term inter-ISO power exchange contract. IBMM provides more opportunities for GENCOs of the host ISO to obtain their preferred maintenance time slots. Additionally, the power system reliability can be ensured. IBMM is formulated as a mixed-integer non-linear bidding programming problem. Then, the bidding programming problem is recast into a mixed-integer second-order cone programming (MISOCP) problem that can be solved using Gurobi. In the case study, the IEEE 118-bus network is studied to illustrate the performance of the proposed bidding strategy.","Generation unit maintenance; Inter-ISO energy exchange; Maintenance bidding mechanism; Mixed-integer non-linear programming problem","en","journal article","","","","","","","","","","","Team Bart De Schutter","","",""
"uuid:ae822841-21eb-4f4c-9b9b-ca140d3ab533","http://resolver.tudelft.nl/uuid:ae822841-21eb-4f4c-9b9b-ca140d3ab533","Evaluation of Global Land Use–Land Cover Data Products in Guangxi, China","Hao, Xuan (Guangxi Normal University; International Research Center for Big Data for Sustainable Development Goals; Chinese Academy of Sciences); Qiu, Yubao (International Research Center for Big Data for Sustainable Development Goals; Chinese Academy of Sciences; China-ASEAN Regional Innovation Center for Big Earth Data); Jia, Guoqiang (International Research Center for Big Data for Sustainable Development Goals; Chinese Academy of Sciences; China-ASEAN Regional Innovation Center for Big Earth Data); Menenti, M. (TU Delft Optical and Laser Remote Sensing; Chinese Academy of Sciences); Ma, Jiangming (Guangxi Normal University); Jiang, Zhengxin (Chinese Academy of Sciences)","","2023","Land use–land cover (LULC) is an important feature for ecological environment research, land resource management and evaluation. Although global high-resolution LULC data sets are booming, their regional performances were still evaluated in limited regions. To demonstrate the local applicability of global LULC data products, six emerging LULC data products were evaluated and compared in Guangxi, China. The six products used are European Space Agency GlobCover (ESAGC), ESRI Land Use–Land Cover (ESRI–LULC), Finer Resolution Observation and Monitoring of Global Land Cover (FROM–GLC), the China Land Cover Dataset (CLCD), the Global Land Cover product with Fine Classification System at 30 m (GLC_FCS30) and GlobeLand30 (GLC30). Reference data were obtained from the local government statistical yearbook and high-resolution remote sensing images on Google Earth. The results showed that CLCD, ESRI–LULC and GLC30 were found to agree well with the forest reference data, with the highest correlation coefficient of 0.999. For the cropland areas, GLC30, CLCD and ESAGC agreed well with the reference data, and the highest correlation coefficient was 0.957. Combined with the comparison with the high-resolution images obtained by Google Earth, we finally concluded that ESAGC, CLCD and GLC30 can best represent the LULCs in Guangxi. Furthermore, the spatial consistency analysis showed that three or more products identified the same LULC type as high as 96.98% of the area. We suggest that majority voting might be applied to global LULC products to provide fused products with better performances on a regional or local scale to avoid the error caused by a single data product.","data inter-comparison; forest and cropland; fusion; land use–land cover; spatial consistency analysis","en","journal article","","","","","","","","","","","Optical and Laser Remote Sensing","","",""
"uuid:8faa9aad-c3cf-4f81-b766-0e7362b54e51","http://resolver.tudelft.nl/uuid:8faa9aad-c3cf-4f81-b766-0e7362b54e51","Inter-Organizational Collaboration in Interconnected Infrastructure Projects","de Bruijne, M.L.C. (TU Delft Organisation & Governance); Hertogh, M.J.C.M. (TU Delft Integral Design & Management); Bakker, H.L.M. (TU Delft Integral Design & Management); Rikhtegarnezami, M. (TU Delft Integral Design & Management)","","2023","This study aims to identify which factors affect inter-organizational collaboration (IOC) in interconnected infrastructure projects to enable practitioners to establish a collaborative environment at the project level. This specific form of inter-organizational collaboration (IOC) is characterized as “horizontal” and has received limited attention in the literature. To this end, a systematic literature review and Q-methodology were conducted. The Q-methodology involves practitioners from various infrastructure organizations in the Netherlands gaining insights into their perspectives on IOC in interconnected infrastructure projects. The study identifies two perspectives: a “holistic, goal-oriented” perspective that recognizes various dimensions of IOC and a more “people-oriented” perspective that emphasizes the value of individual factors for IOC. The findings suggest that multiple perspectives on collaboration exist among practitioners, potentially affecting collaboration in interconnected infrastructure projects. Awareness of the need to manage practitioners’ perspectives, and addressing and discussing these differences, can stimulate inter-organizational collaboration and contribute to improved project performance.","inter-organizational collaboration; collaboration factors; interconnected infrastructure projects","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:bf160278-9e15-4ab0-939e-723f09895c30","http://resolver.tudelft.nl/uuid:bf160278-9e15-4ab0-939e-723f09895c30","Ambiguity-Fixing in Frequency-Varying Carrier Phase Measurements: Global Navigation Satellite System and Terrestrial Examples","Khodabandeh, A. (University of Melbourne); Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; University of Melbourne; Curtin University)","","2023","Carrier phase signals are considered among the key observations in global navigation satellite systems (GNSSs) and several other high-precision interferometric measurement systems. However, these ultra-precise measurements are not fully exploited when the integerness of their inherent ambiguities is discarded during the estimation process. Provided that the integer-estimable functions of their phase ambiguities are properly identified, integer ambiguity resolution (IAR) can be utilized to benefit their parameter solutions. For the GNSS code division multiple access systems with transmitters that broadcast carrier phase signals on identical frequencies, these integer-estimable functions have been characterized and are well-known as double differenced ambiguities. However, this is not the case with “frequency-varying” carrier phase signals that are broadcast by GLONASS satellites, Low-Earth-Orbiting communication satellites, or cellular long-term evolution (LTE) transmitters. This study aims to present full-rank models that can be used to identify integer-estimable ambiguity functions, thereby bringing the observation equations of frequency-varying carrier phase measurements into an IAR-applicable form. Our analytical results are supported by several numerical examples, including GNSS and terrestrial-based IAR as well as a new set of “inter-frequency” integer ambiguities that this study discovers in Galileo multi-frequency carrier phase signals.","global navigation satellite systems (GNSS); integer ambiguity resolution (IAR); integer-estimability; inter-frequency ambiguities; interferometric parameter estimation","en","journal article","","","","","","","","","","","Mathematical Geodesy and Positioning","","",""
"uuid:fd0be83c-9028-4207-885c-4103627af0a8","http://resolver.tudelft.nl/uuid:fd0be83c-9028-4207-885c-4103627af0a8","Creating points of opportunity in sustainability transitions: Reflective interventions in inter-organizational collaboration","Eikelenboom, Manon (Vrije Universiteit Amsterdam); van Marrewijk, A.H. (TU Delft Design & Construction Management; Vrije Universiteit Amsterdam; BI Norwegian Business School)","","2023","This paper addresses the lack of attention for the behaviours and agency of actors in organizations in the sustainability transitions literature by focussing on practices of inter-organizational collaboration in the transition to circular construction. Practices of inter-organizational collaboration can slow down this transition and are deeply embedded in the construction regime, creating critical points of intersection. This research therefore investigated how reflective interventions can enable project actors to change their practices and support the transformation of critical points of intersection into points of opportunity in circular construction. To answer this question, we adopted a case study approach with action research elements. The results of this study contribute to the sustainability transitions literature by showing how reflective interventions can assist in the transformation of critical points of intersection through five processes, including prioritising reflection on practices, critically evaluating practices, creating a breeding ground for new practices, implementing new practices and embedding new practices in partner organizations. Furthermore, we move away from the focus on policy interventions and offer more room for the agency of actors in projects, by showing how reflective interventions can create experimental environments close to the day-to-day activities of project actors enabling them to simultaneously unlearn obsolete practices and learn new practices.","Circular construction; Inter-organizational collaboration; Practices; Reflective interventions; Sustainability transitions","en","journal article","","","","","","","","","","","Design & Construction Management","","",""
"uuid:e170c27e-c3d4-4a19-81b5-caed0cd780d1","http://resolver.tudelft.nl/uuid:e170c27e-c3d4-4a19-81b5-caed0cd780d1","Unveiling the inequalities in virtual water transfer in China: The environmental and economic perspectives","Wei, Ziyi (Beijing Forestry University); Huang, Kai (Beijing Forestry University); Chen, Ying (Beijing Forestry University); Wang, D. (TU Delft Sanitary Engineering); Yu, Yajuan (Beijing Institute of Technology); Xu, Ming (Tsinghua University); Kapelan, Z. (TU Delft Sanitary Engineering)","","2023","To alleviate the geographical mismatch between supply and demand of water resources, virtual water trade had attracted extensive attention. Many studies had estimated the virtual water flow and measured the virtual water inequality using Environmental Input-Output (EIO) model. However, EIO model ignores the feedback effect in the trade, which may lead an overestimation or underestimation of virtual water transfer. Moreover, while considering the relation between economic benefits and environmental costs, the studies of virtual water inequality are still limited in both number and methodology. Here, to address these gaps, we recalibrated the virtual water and value-added transfer in China's 30 provinces in 2017 using a new Environmental Spillover-Feedback Effects (ESFEs) model, and then measured the inequality between virtual water transfer and the resource endowments taking the value-added into account. Our results show that the virtual water transfer of half of provinces changed exceeding 50 %, with a maximum of 428 %. The ratio of net virtual water outflow to one-way virtual water inflow (which is called virtual water plunder index in this study) in Xinjiang is up to 935 %, which directly contributing to the inequality among regions. Moreover, the virtual water transfer in different regions is not compensated equally from the perspective of economy. As a result, some regions are getting both water resources and economic benefits, while others are getting the opposite. Our study highlights the importance of considering both the pressure on water resources and economic benefits when measuring the virtual water inequality. Our findings support policymakers in developing adequate responses, i.e., clarifying regional responsibilities of virtual water trade, building a whole industrial chain, and balancing the transfer of value-added and virtual water.","Inequality; Inter-regional transfer; Spillover-feedback effects; Virtual water trade","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.","","2024-03-18","","","Sanitary Engineering","","",""
"uuid:3ba5e622-a128-4843-bf25-cb210d69506e","http://resolver.tudelft.nl/uuid:3ba5e622-a128-4843-bf25-cb210d69506e","Autonomous navigation for deep space small satellites: Scientific and technological advances","Turan, E. (TU Delft Space Systems Egineering); Speretta, S. (TU Delft Space Systems Egineering); Gill, E.K.A. (TU Delft Space Systems Egineering)","","2022","In recent years, there is a growing interest in small satellites for deep space exploration. The current approach for planetary navigation is based on ground-based radiometric tracking. A new era of low-cost small satellites for space exploration will require autonomous deep space navigation. This will decrease the reliance on ground-based tracking and provide a substantial reduction in operational costs because of crowded communication networks. In addition, it will be an enabler for future missions currently impossible. This review investigates available deep space navigation methods from an autonomy perspective, considering trends in proposed deep space small satellite missions. Autonomous crosslink radiometric navigation, which is one of the best methods for small satellites due to its simplicity and the use of existing technologies, is studied, including available measurement methods, enabling technologies, and applicability to the currently proposed missions. The main objective of this study is to fill the gap in the scientific literature on the autonomous deep space navigation methods, deeply for crosslink radiometric navigation and to aim at showing the potential advantages that this technique could offer to the missions being analyzed. In this study, a total of 64 proposed deep space small satellite missions have been analyzed found from a variety of sources including journal papers, conference proceedings, and mission websites. In those missions, the most popular destinations are found to be cislunar space and small bodies with the purpose of surface mapping and characterization. Even though various autonomous navigation methods have been proposed for those missions, most of them have planned to use the traditional ground-based radiometric tracking for navigation purposes. This study also shows that more than half of the missions can benefit from the crosslink radiometric navigation through the inter-satellite link.","Autonomy; Communication; Deep space; Inter-satellite link; Navigation; Small satellite","en","review","","","","","","","","","","","Space Systems Egineering","","",""
"uuid:d59efa06-be2f-4a68-9f20-1162678569ae","http://resolver.tudelft.nl/uuid:d59efa06-be2f-4a68-9f20-1162678569ae","Multi-Graph Convolutional-Recurrent Neural Network (MGC-RNN) for Short-Term Forecasting of Transit Passenger Flow","He, Yuxin (Shenzhen Technology University); Li, L. (TU Delft Air Transport & Operations); Zhu, X. (TU Delft Air Transport & Operations; City University of Hong Kong); Tsui, Kwok Leung (Virginia Tech)","","2022","Short-term forecasting of passenger flow is critical for transit management and crowd regulation. Spatial dependencies, temporal dependencies, inter-station correlations driven by other latent factors, and exogenous factors bring challenges to the short-term forecasts of passenger flow of urban rail transit networks. An innovative deep learning approach, Multi-Graph Convolutional-Recurrent Neural Network (MGC-RNN) is proposed to forecast passenger flow in urban rail transit systems to incorporate these complex factors. We propose to use multiple graphs to encode the spatial and other heterogenous inter-station correlations. The temporal dynamics of the inter-station correlations are also modeled via the proposed multi-graph convolutional-recurrent neural network structure. Inflow and outflow of all stations can be collectively predicted with multiple time steps ahead via a sequence to sequence(seq2seq) architecture. The proposed method is applied to the short-term forecasts of passenger flow in Shenzhen Metro, China. The experimental results show that MGC-RNN outperforms the benchmark algorithms in terms of forecasting accuracy. Besides, it is found that the inter-station driven by network distance, network structure, and recent flow patterns are significant factors for passenger flow forecasting. Moreover, the architecture of LSTM-encoder-decoder can capture the temporal dependencies well. In general, the proposed framework could provide multiple views of passenger flow dynamics for fine prediction and exhibit a possibility for multi-source heterogeneous data fusion in the spatiotemporal forecast tasks.","Correlation; Forecasting; inter-station correlation; multi-graph-convolution.; Predictive models; Rails; Short-term forecasting of passenger flow; spatiotemporal dependencies; Spatiotemporal phenomena; Time series analysis; Transportation","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","","","Air Transport & Operations","","",""
"uuid:01b383c5-65f5-430c-ad31-36fca88f606f","http://resolver.tudelft.nl/uuid:01b383c5-65f5-430c-ad31-36fca88f606f","Inter-Annual and Seasonal Variability of Flows: Delivering Climate-Smart Environmental Flow Reference Values","Salinas Rodriquez, Sergio (TU Delft Water Resources; The Southern Border College); van de Giesen, N.C. (TU Delft Water Resources); McClain, M.E. (TU Delft Water Resources; IHE Delft Institute for Water Education)","","2022","Environmental flow (eflow) reference values play a key role in environmental water science and practice. In Mexico, eflow assessments are set by a norm in which the frequency of occurrence is the managing factor to integrate inter-annual and seasonal flow variability components into environmental water reserves. However, the frequency parameters have been used indistinctively between streamflow types. In this study, flow variability contributions in 40 rivers were evaluated based on hydrology, climate, and geography. Multivariate assessments were conducted based on a standardized contribution index for the river types grouping (principal components) and significant differences (one-way PERMANOVA). Eflow requirements for water allocation were calculated for different management objectives according to the frequency-of-occurrence baseline and an adjustment to reflect the differences between river types. Results reveal that there are significant differences in the flow variability between hydrological conditions and streamflow types (p-values < 0.05). The performance assessment reveals that the new frequency of occurrence delivers climate-smart reference values at least at an acceptable level (for 85–87% of the cases, r2 ≥ 0.8, slope ≤ 3.1), strengthening eflow assessments and implementations.","climate-smart; environmental flows; frequency of occurrence; inter-annual and seasonal variability; one-way PERMANOVA; principal component analysis; reference values; streamflow; water allocation","en","journal article","","","","","","","","","","","Water Resources","","",""
"uuid:90448b18-bbfa-45f3-8b55-ee1fdd80a3b8","http://resolver.tudelft.nl/uuid:90448b18-bbfa-45f3-8b55-ee1fdd80a3b8","A Crystal-Less Clock Generation Technique for Battery-Free Wireless Systems","Chang, Ziyi (Zhejiang University); Zhang, Yunshan (Zhejiang University); Yang, Changgui (Zhejiang University); Luo, Yuxuan (Zhejiang University); Du, S. (TU Delft Electronic Instrumentation); Chen, Yong (University of Macau); Zhao, Bo (Zhejiang University)","","2022","The size of wireless systems is required to be reduced in many applications, such as ultra-low-power sensor nodes and wearable/implantable devices, where battery and crystal are the two main bottlenecks in system miniaturization. In recent years, battery-free radios based on wireless power transfer (WPT) have shown great potential in miniature wireless systems, while a reliable on-chip clock without a crystal remains a design challenge. Conventional methods utilized the RF WPT tone as the reference for clock generation, but the high RF frequency leads to high power consumption. In comparison, using a lower WPT frequency results in an antenna with a larger size. In this work, the 2nd-order inter-modulation (IM2) component of the two RF WPT tones is extracted to lock an on-chip oscillator, providing a low-jitter PVT-robust clock. In this way, the wireless systems can benefit from: 1) The clock recovery circuits operate at a low IM2 frequency, reducing the power consumption. 2) The WPT can be set to a high RF frequency to minimize the antenna. Fabricated in 65 nm CMOS process, the proposed crystal-less clock generator takes a small area of 0.023 mm2 in a wireless system chip. Measured results show -92 dBc/Hz@10 kHz phase noise and 6.8 μ W power.","Antennas; Battery-free; clock generator; Clocks; Crystals; Generators; injection locking; inter-modulation; Radio frequency; System-on-chip; Wireless communication; wireless power transfer (WPT)","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 Instrumentation","","",""
"uuid:27f83ef5-44f2-49fe-9f21-db4cd9ef9bc1","http://resolver.tudelft.nl/uuid:27f83ef5-44f2-49fe-9f21-db4cd9ef9bc1","Collaboration and Data Sharing in Inter-Organizational Infrastructure Construction Projects","Rikhtegarnezami, M. (TU Delft Integral Design & Management); de Bruijne, M.L.C. (TU Delft Organisation & Governance); Hertogh, M.J.C.M. (TU Delft Integral Design & Management); Bakker, H.L.M. (TU Delft Integral Design & Management)","","2022","A close collaboration between infrastructure owners is crucial to address challenges in the design and execution of next-generation infrastructure projects for sustainable development. Managing and sharing data among parties involved in infrastructure projects, particularly the data required at the early stages of a project to design and develop an interconnected infrastructure project, appear to play a critical role in inter-organizational collaboration (IOC), but are often overlooked. In the present work, the status of collaboration and data sharing between infrastructure owners in inter-organizational infrastructure projects is studied to enhance our understanding of the relationship between collaboration and data sharing in horizontal IOCs. Explorative semi-structured interviews with practitioners were conducted at organizational and project levels in the infrastructure sectors in The Netherlands. The outcomes revealed that the theoretical benefits of IOC are not realized in practice and that managing and sharing data between infrastructure owners in inter-organizational projects (IOP) face many challenges. The findings suggest that collaboration and data sharing are interrelated in horizontal IOCs and are deemed crucial for the execution of IOPs. The findings of the present study demonstrate the importance of the bilateral relationship between effective collaboration and data sharing and provide an enhanced insight into horizontal forms of IOC and practices of next-generation infrastructure development.","interconnected infrastructure; inter-organizational projects; horizontal collaboration; data sharing; inter-organizational project management; inter-organizational collaboration","en","journal article","","","","","","","","","","","Integral Design & Management","","",""
"uuid:3d95605c-de1c-4ed6-88ff-0ca0fc68c6f4","http://resolver.tudelft.nl/uuid:3d95605c-de1c-4ed6-88ff-0ca0fc68c6f4","Experimental and numerical validation of an inter-ply friction model for thermoset based fibre metal laminate under hot-pressing conditions","Liu, S. (TU Delft Aerospace Manufacturing Technologies); Sinke, J. (TU Delft Aerospace Manufacturing Technologies); Dransfeld, C.A. (TU Delft Aerospace Manufacturing Technologies)","Vassilopoulos, Anastasios P. (editor); Michaud, Véronique (editor)","2022","Hot-pressing can be an attractive fabrication method that enables the forming of hybrid materials like thermoset based fibre metal laminates. However, the process simulation on press forming requires accurate material characterization and boundary conditions to facilitate part design for a defect-free component. In order to improve the overall predictive simulation quality, the inter-ply sliding at metal-prepreg interfaces which is one of the critical deformation mechanisms is considered. An inter-ply friction model has been established using an experimental friction test apparatus and the effect of slip rate, normal force and temperature is taken into consideration. To validate the proposed friction model, a comparative study between results obtained from the numerical model and the experimental ones is carried out. The research demonstrates that the inter-ply friction model can be a valuable building block for the finite element simulation of the hot-pressing process for thermoset based fibre metal laminates.","Fibre metal laminates (FMLs); Inter-ply friction; Hot-pressing; Numerical simulation","en","conference paper","EPFL Lausanne, Composite Construction Laboratory","","","","","","","","","","Aerospace Manufacturing Technologies","","",""
"uuid:8c909759-c337-45fe-9593-6fc3217461d1","http://resolver.tudelft.nl/uuid:8c909759-c337-45fe-9593-6fc3217461d1","Choice-driven service network design for an integrated fixed line and demand responsive mobility system","Sharif Azadeh, S. (TU Delft Transport and Planning); van der Zee, J. (Erasmus Universiteit Rotterdam); Wagenvoort, M. (Erasmus Universiteit Rotterdam)","","2022","Sparsely populated areas tend to be poorly served by Fixed Line and Schedule (FLS) public transport systems as the operation of a regular bus line is not economically viable for such areas. Therefore, introducing a Demand Responsive Transport (DRT) to partially replace FLS can result in increasing mobility service accessibility and inclusion. In this paper, a mixed-integer linear problem (MILP) is proposed to design an integrated FLS and DRT network for a transport operator. Passengers behavior is implicitly incorporated in our proposed approach via a discrete choice model. In addition, a tailored Adaptive Large Neighborhood Search (ALNS) coupled with tabu search and simulated annealing are introduced. We test our algorithm on real instances from a public transport operator in the Netherlands. The proposed algorithm can solve the problem up to 170 times faster than the MILP within 4% to 10% gap. Our proposed resolution approach investigates the temporal and spatial feasibility of deploying these integrated mobility systems based on the service level and provides recommendations to public transport operators.","Choice models; Demand Responsive Transport (DRT); Fixed-Line and Schedule (FLS) public transport; Heuristics; Inter-modal mobility; MILP","en","journal article","","","","","","","","","","","Transport and Planning","","",""
"uuid:05057cef-0f2c-4211-9c92-ee81a03d22e3","http://resolver.tudelft.nl/uuid:05057cef-0f2c-4211-9c92-ee81a03d22e3","Comparison of Radar Receivers for OFDM and OTFS waveforms","Correas Serrano, A. (Fraunhofer FHR - Cognitive Radar); Petrov, N. (TU Delft Microwave Sensing, Signals & Systems; NXP Semiconductors); Gonzalez-Huici, Maria (Fraunhofer FHR - Cognitive Radar); Yarovoy, Alexander (TU Delft Microwave Sensing, Signals & Systems)","","2022","A generic description for common multi-carrier radar receivers is proposed. Two multi-carrier waveforms - orthogonal frequency division multiplexing (OFDM) and orthogonal time-frequency spacing (OTFS) - which could be used for joint radar and communication (JRC) applications - are considered. Sensing performances of different waveform-receiver pairs are compared theoretically. It is shown that while qualitatively, both waveforms perform similarly under the same receiver, performance differences exist between them.","integrated side lobe ratio; inter-carrier interference; multicarrier radar; Orthogonal frequency division multiplexing; Orthogonal time-frequency spacing","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.","","2022-12-25","","","Microwave Sensing, Signals & Systems","","",""
"uuid:e9b07f55-7f05-4808-9826-620aca45d240","http://resolver.tudelft.nl/uuid:e9b07f55-7f05-4808-9826-620aca45d240","Strategies to advance the dream of integrated digital public service delivery in inter-organizational collaboration networks","Wouters, Stijn (Katholieke Universiteit Leuven); Janssen, M.F.W.H.A. (TU Delft Engineering, Systems and Services); Lember, Veiko (Katholieke Universiteit Leuven; Tallinn University of Technology); Crompvoets, Joep (Katholieke Universiteit Leuven)","","2022","Public administrations are increasingly relying on collaboration within inter-organizational networks to coordinate the development and provisioning of integrated digital public services. Collaboration strategies are necessary to focus collaborative efforts, align and prioritize goals, and leverage concrete results that advance integrated service delivery (ISD). However, literature on inter-organizational collaboration strategies for integrated service delivery is scarce. This research identifies collaboration strategies in three qualitative case studies in Belgium. The cases present 33 collaboration strategies categorized into engagement, motivation, and joint action strategies. Collaboration strategies should complement each other. Together these strategies can help to overcome the adoption paradox, one of the key issues to advance ISD, which refers to service providers not being inclined to adopt an ISD unless it has many users, but users might not be willing to use and ISD before many service providers have adopted it. Policy-makers can use the identified collaboration strategies to advance integrated service delivery.","Adoption paradox; Collaboration strategies; E-government; Integrated service delivery; Inter-organizational collaboration","en","journal article","","","","","","","","","","Engineering, Systems and Services","","","",""
"uuid:f13cee50-1664-499e-8b29-ff89cb900fa5","http://resolver.tudelft.nl/uuid:f13cee50-1664-499e-8b29-ff89cb900fa5","Potential zones for offshore wind power development in the Gulf of Mexico using reanalyses data and capacity factor seasonal analysis","Canul-Reyes, D. A. (Universidad Nacional Autónoma de México); Rodríguez-Hernández, O. (Universidad Nacional Autónoma de México); Jarquin Laguna, A. (TU Delft Offshore and Dredging Engineering)","","2022","Mexico is an attractive candidate for offshore wind energy development due to its geographical location with extensive coasts in the Pacific Ocean and Mexico's Gulf. Although potential offshore wind areas have been geographically assessed, an evaluation of the seasonal variations of the capacity factors has not been considered for the feasibility of the locations. This research identifies potential zones for offshore wind development in the Gulf of Mexico, implementing geographical restrictions such as the Economic Exclusive Zone, distance from the coast, protected areas, bathymetry, and capacity factor seasonality. Wind speeds were obtained from 39 years of reanalyses historical data and two reference wind turbines of 5 and 10 MW were included in the analysis. Three potential areas were identified from the results: the northeast Tamaulipas, the western Campeche, and the northern Yucatan. Monthly mean capacity factors above 45% were estimated from October to June, with the maximum values near 60% between March and April. Conversely, minimum values were observed from July to September but consistently higher than 30%. The analyzed zones show suitable technical conditions for offshore wind development. Further analysis is needed to validate the wind speed conditions, in addition to the evaluation of economic factors, the study of extreme weather conditions like tropical cyclones as well as characteristics in the intertropical region.","Capacity factor analysis; ERA5; Inter annual variability; MERRA2; Offshore wind in the Gulf of Mexico; Wind resource assessment","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","","","Offshore and Dredging Engineering","","",""
"uuid:c5597a1e-37a0-485a-ae6c-b1e3ef8cd458","http://resolver.tudelft.nl/uuid:c5597a1e-37a0-485a-ae6c-b1e3ef8cd458","An inter-city energy migration framework for regional energy balance through daily commuting fuel-cell vehicles","He, Yingdong (Hunan University; University of California); Zhou, Yuekuan (The Hong Kong University of Science and Technology; HKUST Shenzhen-Hong Kong Collaborative Innovation Research Institute); Liu, Jia (Guangzhou University; The Hong Kong Polytechnic University); Liu, Zhengxuan (TU Delft Design & Construction Management; Hunan University); Zhang, Guoqiang (Hunan University)","","2022","Spatiotemporal energy interaction and sharing are promising solutions to penetrate renewable energy, enhance grid power stability, and improve regional energy flexibility. However, the current literature is restrained in a small-scale neighborhood level, without considering inter-city energy migration through spatiotemporal complementarity between renewable-abundant regions (like suburb or countryside areas) and demand-shortage regions (like city centers). In this study, the energy interaction boundary is extended from a neighborhood scale to an inter-city scale, to maximize the renewable energy penetration, demand coverage, and reduce regional energy imbalance. This study firstly proposes a holistic framework on inter-city transportation-based energy migration, consisting of a residential community with rooftop photovoltaic systems and electrical batteries, an office building, hydrogen vehicles (HVs), a hydrogen (H2) station, and local power grids, for the energy transmission between building groups in spatially different regions through the daily commuting of HVs. Optimal grid-regulation strategies are thereafter proposed and adopted to stabilize the grid power and reduce energy costs. Parametric analysis on energy trading strategies and prices has been conducted, to improve the participation motivations of different stakeholders. Results indicate that, compared to the reference case with isolated buildings and vehicles, the transportation-based energy migration framework covers 23.2 % of the office energy demand and elevates the community's renewable self-use ratio from 72.7 % to 98.6 %. Meanwhile, the maximum grid-export power in the renewable-abundant region (suburb residential community) and the annual grid-import power in the demand-shortage region (city-center office) are reduced by up to 86.9 % (from 155.7 to 20.4 kW) and 29.4 % (from 49.0 to 34.6 kW), respectively. Moreover, even considering the fuel cell degradation cost of HVs, the transportation-based energy migration framework reduces the operating costs of the office building and HVs (the H2 cost and the fuel cell degradation cost) by 16.4 % (from $52791.3 to $44154.7) and 1.7 % (from $27172.5 to $26707.4), respectively. Afterward, compared to the reference case, the peak-shaving and load-shaping grid-regulation strategies can decrease the peak grid-export power of the community by about 71.6 % (from 155.7 to 44.2 kW), and the maximum grid-import power of the office by 23.7 % (from 49.0 to 37.4 kW), respectively. Furthermore, the transportation-based energy migration framework is economically feasible, only when the renewable export price for H2 production is 0.07 $/kWh, the onsite-renewable-generated H2 lower than 6.5 $/kg for the HV owners, and the vehicle-to-building electricity lower than 0.3 $/kWh for the office building. This study provides a novel inter-city energy migration framework with hydrogen networks to enhance district energy sharing, improve regional energy balance and reduce carbon emission, together with frontier guidelines on energy trading prices to promote participation motivations from different stakeholders.","Distributed hydrogen infrastructure; Energy trading; Hydrogen economy; Innovative Grid-regulation strategy; Spatiotemporal energy sharing network; Transportation-based Inter-city energy migration","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.","","2023-01-31","","","Design & Construction Management","","",""
"uuid:40de9698-1561-4c15-bb4f-f6d8a6c9e3a1","http://resolver.tudelft.nl/uuid:40de9698-1561-4c15-bb4f-f6d8a6c9e3a1","Dryland avulsion sequences: Insights from data-model comparison of a terminal dryland river system","Karamitopoulos, P. (TU Delft Hydraulic Structures and Flood Risk); Donselaar, M.E. (TU Delft Applied Geology; Katholieke Universiteit Leuven); Weltje, G. J. (Katholieke Universiteit Leuven); van Toorenenburg, K. A. (Shell International Exploration and Production BV)","","2022","An advection–diffusion model of fluvial processes was used to analyze the stratigraphic expression of avulsions in terminal river systems and understand their control on basin-fill architecture. The initial and boundary conditions of the model runs (i.e., catchment area, smoothed initial topographic surface, grain-size distribution and sediment supply rates) were extracted from the modern Rio Colorado dryland terminal river system in the Altiplano Basin (Bolivia). Water-discharge and sediment-load values were derived from global regression curves and the BQART equation, respectively. To evaluate the robustness of the simulations, the model was tested under increasing sediment-load scenarios ranging from 0.003 m3/s to 0.095 m3/s. Data-model comparison provided insights into the role of avulsions in the geomorphological evolution of terminal river systems. The observed stacking of sediments, as captured by geospatial and geochronological data from the Rio Colorado, is consistent with the high sediment-load scenarios, which start with a single-thread fluvial channel that in time radially expands over the floodplain by successive river avulsions on account of alluvial-ridge aggradation and channel-floor elevation above the surrounding floodplain. The model output shows a laterally extensive, convex-upwards lobate topography which is in agreement with the lateral and longitudinal geomorphology in the upper and lower coastal plain of the Rio Colorado. The simulated inter-avulsion period, which is the time period between two successive full (or stabilized) avulsions in the model, varies from 0.18 to 1.2 kyr and is consistent with the OSL-age determination in the Rio Colorado with inter-avulsion periods up to 1.28 ± 0.34 kyr.","Compensational stacking; Dryland river system; Fluvial geomorphology; Inter-avulsion period; Numerical simulation; River avulsion","en","journal article","","","","","","","","","","","Hydraulic Structures and Flood Risk","","",""
"uuid:b835d8f3-fc44-43a7-a30a-a574a8e019f8","http://resolver.tudelft.nl/uuid:b835d8f3-fc44-43a7-a30a-a574a8e019f8","A Novel Engine Architecture for Low NOx Emissions","Blondeel, Tim (Student TU Delft); Yin, F. (TU Delft Aircraft Noise and Climate Effects); Gangoli Rao, A. (TU Delft Flight Performance and Propulsion)","","2022","The fuel efficiency of turbofan engines has improved significantly, hence reducing aviation's CO2 emissions. However, the increased operating pressure and temperature for fuel efficiency cause adverse effects on NOx emissions. Therefore, a novel engine concept, which can reduce NOx emissions without affecting the cycle efficiency, is of high interest to the aviation community. This paper investigates the potential of an intercooler and inter-turbine burner (ITB) for the future low NOx aircraft propulsion system. The study evaluates performance and NOx emissions of four engine architectures: a very high bypass ratio (VHBR) turbofan engine (baseline), a VHBR engine with intercooler, a VHBR engine with ITB, and a VHBR engine with both intercooler and ITB. The cycles are optimized for minimum cruise Thrust Specific Fuel Consumption (TSFC), considering the same design space, thrust requirements, and operational constraints. The ITB is only used during take-off to minimize cruise fuel consumption. The analysis shows that using an ITB solely, with the energy split of 75% (the first burner) / 25% (ITB), reduces the cruise NOx emission by 26%, and the cruise TSFC slightly by 0.5%. The intercooler alone reduces the NOx emissions by 16% and the cruise TSFC by 0.8%. The combination of intercooler and ITB reduces the NOx emissions further by 38%. The analysis confirms that introducing an intercooler and ITB can potentially resolve the contradicting effects of fuel efficiency and NOx emissions for the future advanced turbofan engine.","Inter-stage turbine burner; Intercooler; low NOemissions; Novel turbofan architecture","en","conference paper","The American Society of Mechanical Engineers (ASME)","","","","","","","","","","Aircraft Noise and Climate Effects","","",""
"uuid:66b4e176-235e-4abb-80ed-a930a4f8c312","http://resolver.tudelft.nl/uuid:66b4e176-235e-4abb-80ed-a930a4f8c312","An online adaptive plan library approach for intensity modulated proton therapy for head and neck cancer","Oud, Michelle (Erasmus MC); Breedveld, Sebastiaan (Erasmus MC); Giżyńska, Marta (Holland Particle Therapy Centre); Kroesen, Michiel (Erasmus MC; Holland Particle Therapy Centre); Hutschemaekers, Stefan (Holland Particle Therapy Centre); Habraken, S.J.M. (Erasmus MC; Holland Particle Therapy Centre); Petit, Steven (Erasmus MC); Perko, Z. (TU Delft RST/Reactor Physics and Nuclear Materials); Heijmen, Ben (Erasmus MC); Hoogeman, M.S. (Erasmus MC; Holland Particle Therapy Centre)","","2022","Background and purpose: In intensity modulated proton therapy (IMPT), the impact of setup errors and anatomical changes is commonly mitigated by robust optimization with population-based setup robustness (SR) settings and offline replanning. In this study we propose and evaluate an alternative approach based on daily plan selection from patient-specific pre-treatment established plan libraries (PLs). Clinical implementation of the PL strategy would be rather straightforward compared to daily online re-planning. Materials and methods: For 15 head-and-neck cancer patients, the planning CT was used to generate a PL with 5 plans, robustly optimized for increasing SR: 0, 1, 2, 3, 5 mm, and 3% range robustness. Repeat CTs (rCTs) and realistic setup and range uncertainty distributions were used for simulation of treatment courses for the PL approach, treatments with fixed SR (fSR3) and a trigger-based offline adaptive schedule for 3 mm SR (fSR3OfA). Daily plan selection in the PL approach was based only on recomputed dose to the CTV on the rCT. Results: Compared to using fSR3 and fSR3OfA, the risk of xerostomia grade ≥ II & III and dysphagia ≥ grade III were significantly reduced with the PL. For 6/15 patients the risk of xerostomia and/or dysphagia ≥ grade II could be reduced by > 2% by using PL. For the other patients, adherence to target coverage constraints was often improved. fSR3OfA resulted in significantly improved coverage compared to PL for selected patients. Conclusion: The proposed PL approach resulted in overall reduced NTCPs compared to fSR3 and fSR3OfA at limited cost in target coverage.","Daily adaptive radiotherapy; Head and neck cancer; Intensity modulated proton therapy; Inter-fraction motion; Plan library; Proton therapy","en","journal article","","","","","","","","","","","RST/Reactor Physics and Nuclear Materials","","",""
"uuid:31c758bd-77c3-4fb8-9cff-c4db1e757fe1","http://resolver.tudelft.nl/uuid:31c758bd-77c3-4fb8-9cff-c4db1e757fe1","On the fluidization of cohesive powders: Differences and similarities between micro- and nano-sized particle gas–solid fluidization","Kamphorst, R. (TU Delft ChemE/Product and Process Engineering); Wu, K. (TU Delft ChemE/Product and Process Engineering); Salameh, S. (Münster University of Applied Sciences); Meesters, G.M.H. (TU Delft ChemE/Product and Process Engineering); van Ommen, J.R. (TU Delft ChemE/Product and Process Engineering)","","2022","The fluidization of cohesive powders has been extensively researched over the years. When looking at literature on the fluidization of cohesive particles, one will often find papers concerned with only micro- or only nano-sized powders. It is, however, unclear whether they should be treated differently at all. In this paper, we look at differences and similarities between cohesive powders across the size range of several nanometres to 10s of micrometres. Classification of fluidization behaviour based on particle size was found to be troublesome since cohesive powders form agglomerates and using the properties of these agglomerates introduces new problems. When looking at inter-particle forces, it is found that van der Waals forces dominate across the entire size range that is considered. Furthermore, when looking into agglomeration and modelling thereof, it was found that there is a fundamental difference between the size ranges in the way they agglomerate. Where the transition between the types of agglomeration is located is, however, unknown. Finally, how models are made and agglomerate sizes are measured is currently insufficient to accurately predict or measure their sizes consistently.","aggregation; cohesion; fluidized bed; inter-particle forces; nanopowder","en","journal article","","","","","","","","","","","ChemE/Product and Process Engineering","","",""
"uuid:404cd375-f152-4a28-b324-8727497a517d","http://resolver.tudelft.nl/uuid:404cd375-f152-4a28-b324-8727497a517d","Development of an Integrated Analytical Model to Predict the Wet Collapse Pressure of Flexible Risers","Li, X. (TU Delft Marine and Transport Technology)","Hopman, J.J. (promotor); Jiang, X. (copromotor); Delft University of Technology (degree granting institution)","2021","A flexible riser is a multi-layered pipe device which enables deep-water production by connecting seabed facilities to floating vessels. To withstand huge hydro-static pressure, it is required to have strong collapse capacities. At present, the collapse capacity of a flexible riser is designed based on a ""wet collapse'' concept, in which the outer sheath is damaged and the seawater has flooded the annulus. For a given water depth, the hydro-static collapse design of a flexible riser needs to be confirmed by a wet collapse calculation. Calculating the wet collapse pressure of flexible risers is always challenging since the layers within risers are different in geometries and materials. Such a complex cross-sectional configuration makes the numerical simulation become the main approach for collapse analysis, which is quite time-consuming for the design stage. As the production is moving towards ultra-deep water fields, the design of new riser product is being required to achieve a balance between collapse resistance and self-weight. Therefore, there is a demand to develop an efficient tool to facilitate the collapse design. In view of this, this thesis presents an integrated analytical model, which addresses three challenges in the wet collapse analysis of flexible risers: the interlocked layer profiles, the geometric imperfections and the pipe curvature. The integrated analytical model contributes to the hydro-static collapse design of flexible risers, which can provide the designers a rapid feedback for their designed cross-section configuration. In our research work, the whole collapse analysis conducted by the proposed analytical model takes less than one hour to finish the prediction. Most of the time is spent on modeling the metallic layers for obtaining their equivalent properties. The actually wet collapse calculation given by this analytical model takes only a few seconds. By contrast, the numerical simulation requires 8-12 hours for modeling and consumes 2-3 days on average to complete one job. For companies that are developing new riser product to enable the ultra-deep water production, this proposed integrated analytical model can effectively facilitate the collapse design of new riser products.","Flexible pipes; Wet collapse; Equivalent layer method; Initial ovality; Inter-layer gap; curvature effect; Integrated analytical model; Numerical simulations","en","doctoral thesis","TRAIL Research School","978-90-5584-285-8","","","","","","","","Marine and Transport Technology","","","",""
"uuid:74b9e1be-7060-496e-b1ea-c3ac9d910b26","http://resolver.tudelft.nl/uuid:74b9e1be-7060-496e-b1ea-c3ac9d910b26","Damage accumulation analysis of cfrp cross-ply laminates under different tensile loading rates","Li, X. (TU Delft Structural Integrity & Composites); Saeedifar, M. (TU Delft Structural Integrity & Composites); Benedictus, R. (TU Delft Structural Integrity & Composites); Zarouchas, D. (TU Delft Structural Integrity & Composites)","","2021","This paper investigates the loading rate effect on both mechanical properties and damage accumulation process of [0°2/90°4]S carbon fiber-polymer laminates under tensile loading. In-situ edge observations, Acoustic Emission and Digital Image Correlation techniques were utilized simultaneously to monitor the state of damage in real time. Results showed that the axial modulus and strength were less sensitive to loading rates than failure strain, which increased with the decrease of the loading rate. In the viewpoint of damage accumulation process, high density and uniform distribution of transverse matrix cracks, and H-shape crack patterns, incorporating inter-laminar cracks, were more likely to occur at low loading rates while variable crack spacing occurred at higher rates. When loading rates were lower than a certain level, maximum transverse matrix crack density decreased slightly due to the restriction of relatively widely generated inter-laminar cracks. Furthermore, the cumulative acoustic emission energy of low-frequency signals was linearly correlated to transverse matrix crack density, providing a promising way to quantify crack accumulation in real time. Finally, spatial consistence was observed between transverse matrix cracks at edges and stress concentrations at the exterior 0° ply, and the peaks of axial strain at local concentration regions locate either near the newest cracks or at the place with minimum crack spacing.","Acoustic emission; Cross-ply laminate; Digital image correlation; Inter-laminar crack; Transverse matrix crack","en","journal article","","","","","","","","","","","Structural Integrity & Composites","","",""
"uuid:99ec9156-6ed8-46e6-9263-5d87eff15e99","http://resolver.tudelft.nl/uuid:99ec9156-6ed8-46e6-9263-5d87eff15e99","Webs of Innovation and Value Chains of Additive Manufacturing under Concideration of RRI: D2.1 Literature review","van de Kaa, G. (TU Delft Economics of Technology and Innovation); Sobota, V.C.M. (TU Delft Economics of Technology and Innovation); Ortt, J.R. (TU Delft Economics of Technology and Innovation); van Beers, Cees (TU Delft Economics of Technology and Innovation); Soetanto, Danny (Lancaster University); Spring, Martin (Lancaster University); Martinsuo, Miia (Tampere University); Luomaranta, Toni (Tampere University); Bierwirth, Antonia (Technalia)","","2021","Four extensive literature reviews on factors for innovation success in terms of market, strategic and social impact for additive manufacturing were performed where the focus lies on three levels of analysis; (inter)organizational, business model, and project.","Literature review; economic performance; (inter)organization level; business level; project level; social performance","en","report","","","","","","I AM RRI Identifier: IAMRRI_D2_1_V2_Final Version date: 14.03.2019 Work package: WP2","","","","","Economics of Technology and Innovation","","",""
"uuid:dfc82963-d14b-4ce4-8878-76432a26d6ca","http://resolver.tudelft.nl/uuid:dfc82963-d14b-4ce4-8878-76432a26d6ca","A novel decentralized platform for peer-to-peer energy trading market with blockchain technology","Esmat, A.A.S. (TU Delft Data-Intensive Systems; Erasmus Universiteit Rotterdam); de Vos, M.A. (TU Delft Data-Intensive Systems); Ghiassi-Farrokhfal, Yashar (Erasmus Universiteit Rotterdam); Palensky, P. (TU Delft Intelligent Electrical Power Grids); Epema, D.H.J. (TU Delft Data-Intensive Systems)","","2021","Peer-to-Peer (P2P) energy trading, which allows energy consumers/producers to directly trade with each other, is one of the new paradigms driven by the decarbonization, decentralization, and digitalization of the energy supply chain. Additionally, the rise of blockchain technology suggests unprecedented socio-economic benefits for energy systems, especially when coupled with P2P energy trading. Despite such future prospects in energy systems, three key challenges might hinder the full integration of P2P energy trading and blockchain. First, it is quite complicated to design a decentralized P2P market that keeps a fair balance between economic efficiency and information privacy. Secondly, with the proliferation of storage devices, new P2P market designs are needed to account for their inter-temporal dependencies. Thirdly, a practical implementation of blockchain technology for P2P trading is required, which can facilitate efficient trading in a secured and fraud-resilient way, while eliminating any intermediaries’ costs. In this paper, we develop a new decentralized P2P energy trading platform to address all the aforementioned challenges. Our platform consists of two key layers: market and blockchain. The market layer features a parallel and short-term pool-structured auction and is cleared using a novel decentralized Ant-Colony Optimization method. This market arrangement guarantees a near-optimally efficient market solution, preserves players’ privacy, and allows inter-temporal market products trading. The blockchain layer offers a high level of automation, security, and fast real-time settlements through smart contract implementation. Finally, using real-world data, we simulate the functionality of the platform regarding energy trading, market clearing, smart contract operations, and blockchain-based settlements.","Blockchain technology; Decentralized market clearing; Inter-temporal market products; Peer-to-peer energy trading","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.","","2021-09-09","","","Data-Intensive Systems","","",""
"uuid:34d947cb-e2ef-4030-9b9e-74f0d5f25458","http://resolver.tudelft.nl/uuid:34d947cb-e2ef-4030-9b9e-74f0d5f25458","An inter-ply friction model for thermoset based fibre metal laminate in a hot-pressing process","Liu, S. (TU Delft Aerospace Manufacturing Technologies); Sinke, J. (TU Delft Aerospace Manufacturing Technologies); Dransfeld, C.A. (TU Delft Aerospace Manufacturing Technologies)","","2021","Forming process with pre-stacked and uncured thermoset fibre metal laminate offers improved deformability compared to full-cured laminate especially for the production of complex structural components. This work investigated the friction behaviour at the metal-prepreg interface of glass fibre reinforced aluminium laminate through an inter-ply friction test. The influence of sliding velocity, normal force, fibre orientation and resin viscosity coupled with temperature on static and kinetic friction coefficients were studied. The kinetic friction behavior in the transition region between mixed and hydrodynamic lubrication, showed a good agreement with the Stribeck-curve theory. While for the static friction, a modified Coulomb friction model was found to fit the experimental results. These models were translated into a phenomenological inter-ply friction model which was incorporated into Abaqus/Explicit as a user-defined friction subroutine for verification. The findings contribute to the development of the forming process with fibre metal laminates.","Hot-pressing; Inter-ply friction; Laminated composites; Resin viscosity","en","journal article","","","","","","","","","","","Aerospace Manufacturing Technologies","","",""
"uuid:318d887d-57e8-4990-ac6a-3b066d255ee5","http://resolver.tudelft.nl/uuid:318d887d-57e8-4990-ac6a-3b066d255ee5","Inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait in patients with knee osteoarthritis","Schrijvers, J. C. (Vrije Universiteit Amsterdam); Rutherford, D. (Dalhousie University); Richards, R. (Vrije Universiteit Amsterdam); van den Noort, J. C. (Vrije Universiteit Amsterdam; Universiteit van Amsterdam); van der Esch, M. (Amsterdam Rehabilitation Research Center Reade; Hogeschool van Amsterdam); Harlaar, J. (TU Delft Biomechatronics & Human-Machine Control; Vrije Universiteit Amsterdam; Erasmus MC)","","2021","Background: Gait analysis has been used for decades to quantify knee function in patients with knee osteoarthritis; however, it is unknown whether and to what extent inter-laboratory differences affect the comparison of gait data between studies. Therefore, the aim of this study was to perform an inter-laboratory comparison of knee biomechanics and muscle activation patterns during gait of patients with knee osteoarthritis. Methods: Knee biomechanics and muscle activation patterns from patients with knee osteoarthritis were analyzed, previously collected at Dalhousie University (DAL: n = 55) and Amsterdam UMC, VU medical center (VUmc: n = 39), using their in-house protocols. Additionally, one healthy male was measured at both locations. Both direct comparisons and after harmonization of components of the protocols were made. Inter-laboratory comparisons were quantified using statistical parametric mapping analysis and discrete gait parameters. Results: The inter-laboratory comparison showed offsets in the sagittal plane angles, moments and frontal plane angles, and phase shifts in the muscle activation patterns. Filter characteristics, initial contact identification and thigh anatomical frame definitions were harmonized between the laboratories. After this first step in protocol harmonization, the offsets in knee angles and sagittal plane moments remained, but the inter-laboratory comparison of the muscle activation patterns improved. Conclusions: Inter-laboratory differences obstruct valid comparisons of gait datasets from patients with knee osteoarthritis between gait laboratories. A first step in harmonization of gait analysis protocols improved the inter-laboratory comparison. Further protocol harmonization is recommended to enable valid comparisons between labs, data-sharing and multicenter trials to investigate knee function in patients with knee osteoarthritis.","Gait; Harmonization; Inter-laboratory; Knee biomechanics; Muscle activation; Protocol","en","journal article","","","","","","","","","","","Biomechatronics & Human-Machine Control","","",""
"uuid:d62cca36-a229-4b95-8275-9a90f7cc166c","http://resolver.tudelft.nl/uuid:d62cca36-a229-4b95-8275-9a90f7cc166c","Inter-Organizational Co-Creation: An Approach to Support Energy Transition Projects","Jalali Sohi, A. (TU Delft Integral Design & Management); Rikhtegarnezami, M. (TU Delft Integral Design & Management); Bakker, H.L.M. (TU Delft Integral Design & Management); Hertogh, M.J.C.M. (TU Delft Integral Design & Management)","Cuevas, Roxana (editor); Bodea, Constanta-Nicoleta (editor); Torres-Lima, Pablo (editor)","2021","Societal challenges such as climate change and inefficiency of energysystems more and more crave for a sustainable environment. Research proved thatrestructuring energy systems into more sustainable forms, called “Energy Transition”, has faced challenges. How to deal with these challenges requires the cocreation between various actors with multiple disciplines, expertise, and perspectivesfrom different organizations. The research question to be answered here is whetherco-creation helps the interaction between different actors in an inter-organizationalproject for the sake of better project results. By doing case study research in theNetherlands, an example of co-creation project in its front-end phase was investigatedregarding the interaction among different actors involved in the project. The researchrevealed that in the case of a co-creation project the multiple actors collaborate acrossorganizational boundaries in order to unite. This leads to a better solution-findingapproach. Openness, trust and respect are valued more in co-creation. Moreover,the project team is better integrated to work towards a shared interest which aresocial benefits. The co-creation facilitated the data-sharing among the key actorsin the project which traditionally is influenced highly by the mother-organizations’culture. Further research will investigate the transition in organizations to supportthe co-creation approach.","Energy transition; Co-creation; Inter-organizational projects; Collaboration","en","conference paper","Springer","","","","","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.","","2021-06-18","","","Integral Design & Management","","",""
"uuid:8bf53f0d-9d8d-4b58-a716-73bcc0bdf067","http://resolver.tudelft.nl/uuid:8bf53f0d-9d8d-4b58-a716-73bcc0bdf067","Understanding Actor Roles in Inter-organizational Digital Public Services","Wouters, Stijn (Katholieke Universiteit Leuven); Janssen, M.F.W.H.A. (TU Delft Information and Communication Technology); Crompvoets, Joep (Katholieke Universiteit Leuven)","Scholl, Hans Jochen (editor); Gil-Garcia, J. Ramon (editor); Janssen, Marijn (editor); Kalampokis, Evangelos (editor); Kalampokis, Evangelos (editor); Lindgren, Ida (editor); Rodríguez Bolívar, Manuel Pedro (editor)","2021","Different actor roles in inter-organizational digital public services are often neither understood nor acknowledged. This can result in challenges regarding the proper design and result in a lack of adoption of these services. In the literature, there exist various taxonomies outlining roles such as users, consumers or co-creators, although their value is limited. We define roles as the expectations regarding the actors and their responsibilities in the governance of a digital public service. The aim of this research is to better understand the various roles in inter-organizational digital service provisioning. This objective is achieved by examining existing classifications and using them to analyze the roles in three inter-organizational cases in Belgium. The multiple-case study reveals natural persons and legal entities often combine several roles. Public administrations have to collaborate to establish inter-organizational digital public services, but might be confronted with different perspectives regarding the end-user or other roles. This might lead to tensions and could have consequences regarding adoption. The results show that intermediary roles performed by non-public sector parties, such as mandate holders or private service providers, are lacking in existing classifications. A novel classification is proposed together with suggestions for the concept of roles, taking a comprehensive view on actor roles in the entire service delivery chain.","Actor roles; E-government; Inter-organizational services; Public service delivery","en","conference paper","Springer","","","","","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","","","Information and Communication Technology","","",""
"uuid:b289803d-6b9f-4e7a-b0f7-5720d97cd86c","http://resolver.tudelft.nl/uuid:b289803d-6b9f-4e7a-b0f7-5720d97cd86c","Low-Complexity Equalization of MIMO-OSDM","Han, Jing (Northwestern Polytechnical University); Ma, Shengqian (Northwestern Polytechnical University); Wang, Yujie (Northwestern Polytechnical University); Leus, G.J.T. (TU Delft Signal Processing Systems)","","2020","Orthogonal signal-division multiplexing (OSDM) is an attractive alternative to conventional orthogonal frequency-division multiplexing (OFDM) due to its enhanced ability in peak-to-average power ratio (PAPR) reduction. Combining OSDM with multiple-input multiple-output (MIMO) signaling has the potential to achieve high spectral and power efficiency. However, a direct channel equalization in this case incurs a cubic complexity, which may be expensive for practical use. To solve the problem, low-complexity per-vector and block equalization algorithms of MIMO-OSDM are proposed in this paper for time-invariant and time-varying channels, respectively. By exploiting the channel matrix structures, these algorithms have only a linear complexity in the transformed domain. Simulation results demonstrate their validity and the related performance comparisons.","equalization; inter-vector interference; MIMO; OSDM; underwater acoustic communication","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.","","2020-06-04","","","Signal Processing Systems","","",""
"uuid:9f14dcae-ae01-4973-a051-9a25b11833f3","http://resolver.tudelft.nl/uuid:9f14dcae-ae01-4973-a051-9a25b11833f3","Wave Energy Resource Assessment for Exploitation—A Review","Guillou, Nicolas (Cerema: Center for Studies and Expertise on Risks, the Environment, Mobility and Planning); Lavidas, G. (TU Delft Offshore Engineering); Chapalain, Georges (Cerema: Center for Studies and Expertise on Risks, the Environment, Mobility and Planning)","","2020","Over recent decades, the exploitation of wave energy resources has sparked a wide range of technologies dedicated to capturing the available power with maximum efficiency, reduced costs, and minimum environmental impacts. These different objectives are fundamental to guarantee the development of the marine wave energy sector, but require also refined assessments of available resource and expected generated power to optimize devices designs and locations. We reviewed here the most recent resource characterizations starting from (i) investigations based on available observations (in situ and satellite) and hindcast databases to (ii) refined numerical simulations specifically dedicated to wave power assessments. After an overall description of formulations and energy metrics adopted in resource characterization, we exhibited the benefits, limitations and potential of the different methods discussing results obtained in the most energetic locations around the world. Particular attention was dedicated to uncertainties in the assessment of the available and expected powers associated with wave–climate temporal variability, physical processes (such as wave–current interactions), model implementation and energy extraction. This up-to-date review provided original methods complementing the standard technical specifications liable to feed advanced wave energy resource assessment.
Observations in this frequency bands from Earth are highly challenging as the ionosphere is opaque to these frequency bands. Furthermore, RFI (Radio Frequency Interferences) generated on Earth makes it highly challenging to perform astronomical observations below 30MHz band. The impediments faced by Earth-based or near-Earth-based radio astronomy for these frequency bands is the motivation to perform measurements from the far-side of the moon.
The purpose of using a swarm of nanosatellites to perform low frequency observations is to enable the realization of long observation baselines and additionally, the effective aperture of observation increases with the number of satellites. For the swarm of nanosatellites to operate as a single aperture, it is very important to cross-correlate the information collected by each satellite and this is where the ISL becomes very crucial. Apart from exchanging data collected by the payload, other information such as attitude and timing information needs to be exchanged.
This work derived mission level requirements which would be used to define a suitable communication architecture for space-based radio astronomy missions such as OLFAR. The approach chosen for communication system for such a swarm mission will comprise of two types of ISL: High data-rate directional link that will be used to exchange payload date and low data-rate omni-directional link that will be used to exchange attitude, timing information and be used for localization, positioning and ranging of the nanosatellites in the swarm. This work will present link budgets to show the feasibility of the proposed communication architecture and derive the specs to further design the transceivers.","Communication; Inter-satellite link; Nano-satellite; Satellite Constellation; Radio Astronomy; Swarm; High data-rate communication systems","en","conference paper","","","","","","","","","","","Electronics","","",""
"uuid:8a8ab38e-ac7a-4e73-afaa-4de6b8f0b429","http://resolver.tudelft.nl/uuid:8a8ab38e-ac7a-4e73-afaa-4de6b8f0b429","Determining Mexican climate-adaptive environmental flows reference values for people and nature: A hydrology-based approach for preventive environmental water allocation","Salinas Rodriquez, Sergio (TU Delft Water Resources; TU Delft Water Management)","van de Giesen, N.C. (promotor); McClain, M.E. (promotor); Delft University of Technology (degree granting institution)","2019","Environmental flows (e-flows) science has significantly advanced in the last decades. In Mexico, a standard for e-flow assessments was recently published as a regulatory instrument to support water planning and management. However, the appropriateness of the technical procedure in a climate change context has not been investigated. Do the e-flows cope with the non-stationary challenge of the flow regime and the water availability shifts in the long term? This thesis aimed to determine Mexican climate-adaptive e-flows reference values for people and nature. The research was based on state-of-the-art environmental water science and practice, and on the current national standard for conducting desktop and on-site assessments (Chapter 2). A novel frequency-of-occurrence approach for assessing e-flows and integrating regimes into volumes for water allocation was developed for perennial rivers (Chapter 3), and adjusted for intermittent and ephemeral streams. This was based on the magnitude of the contribution of hydrological wet, average, dry and very dry low flow conditions (inter-annual and seasonal variability), as well as a flood regime per stream type (Chapters 4 and 5). River discharge, basin rainfall trends, and e-flow regimes were examined in a set of 40 study cases selected according to climate, geography and hydrology representativeness. Hydrology-based likely environmental reserve volumes for preventive water allocation, expressed as a percentage of the mean annual runoff, were obtained based on a central range distribution approach. The performance assessment of these reference values demonstrated that the impact on water availability for allocating such volumes is no different from the current method (baseline) though significantly improved for avoiding under and over-estimations.","Flow regime; Inter-anual & seasonal variability; Environmental flows; Environmental water reserve; Hydrology-based desktop approach","en","doctoral thesis","","978-94-028-1561-0","","","","","","","","Water Management","Water Resources","","",""
"uuid:9c06cd80-10a2-465b-ba58-21bf3ad6795e","http://resolver.tudelft.nl/uuid:9c06cd80-10a2-465b-ba58-21bf3ad6795e","Trust unravelled: In inter-organisational relationships in a regulated tender environment","Smolders, A.L. (TU Delft Railway Engineering)","Dollevoet, R.P.B.J. (promotor); Santema, S.C. (copromotor); Veeneman, Wijnand (copromotor); Delft University of Technology (degree granting institution)","2019","Scientists say that trust in inter-organisational relationships leads to high performance, project success, and better quality in construction work. Later research shows that distrust also plays an important role in preventing excessive trust in relationships. It is better to say that a stable state of trust is the balance between trust and distrust and leads to optimal performance. As an employee at the Dutch rail infrastructure manager (the asset owner), my experience in the rail maintenance market is that trust has a limited role in inter-organisational relationships. Inter-organisational relationships are organised via contracts where the output (performance), minimum standards, and tasks and roles are described in detail. Corporate lawyers regularly discuss the requests of change (technically and financially) from the rail maintenance contractors. Trust may have a larger role in inter-organisational relationships between the key figures who manage the contract to improve the output (performance).","trust; distrust; inter-organisational relationship; contract; monopsony; oligopoly","en","doctoral thesis","","978-94-6384-016-3","","","","","","","","","Railway Engineering","","",""
"uuid:bd09eb78-b763-4f07-a12d-08bf5e0fd881","http://resolver.tudelft.nl/uuid:bd09eb78-b763-4f07-a12d-08bf5e0fd881","Exploitative learning in inter-organizational projects: Evidence from Dutch infrastructure practices","Liu, Y. (TU Delft Integral Design & Management); Hertogh, M.J.C.M. (TU Delft Integral Design & Management); Houwing, E.J. (TU Delft Integral Design & Management; Rijkswaterstaat)","","2019","Purpose - How learning is facilitated in inter-organizational projects remains underdeveloped in the literature. The aim of this study is to focus on viewing the relationship between the multiple organizations in a project, from a perspective of the learning aspect. Design/Methodology/Approach - This research analyses the learning trajectory that occurred in the largest tunnel project in the Netherlands. Data were collected through archival documents, in-depth interviews, and site visits. Answering the research question will be done through inductive research. Findings - The results indicate that the most significant change that exploitative learning has led to is the change in mind-set. The learning paradox of projects does not play a factor in the learning trajectory present at the GSP project. Research Limitations/Implications - While the research was conducted in a Dutch context, it is suggested that the findings presented would align with the experiences of construction organizations in other parts of the world. Practical Implications - The findings have implications for understanding learning in practical project management. The organizations need to focus on learning initiatives on people, and not on the collection of data. Originality/Value - This research responds to the debate over the learning in projects. Learning stimulates openness and that this has positive impact omcollaboration.","Exploitative learning; Inductive research; Infrastructure construction projects; Inter-organizational projects; Mind-set change; Organizational culture","en","book chapter","Emerald Publishing","","","","","","","","","","Integral Design & Management","","",""
"uuid:485e78bc-7687-441e-b642-dc354edd9fc5","http://resolver.tudelft.nl/uuid:485e78bc-7687-441e-b642-dc354edd9fc5","How to claim what is mine: Negotiating professional roles in inter-organizational projects","Bos-de Vos, M. (TU Delft Methodologie en Organisatie van Design); Lieftink, B.M. (Radboud Universiteit Nijmegen); Lauche, K. (Radboud Universiteit Nijmegen)","","2019","Professional roles within inter-organizational projects have become increasingly diverse and contested, yet little is known about how professionals react to such threats of marginalization. Drawing on empirical data from interviews with architects, a profession in which historically established role boundaries have become particularly blurred, we analyse how professionals negotiate their roles in
inter-organizational projects. We identified three types of boundary work—reinstating, bending, and pioneering role boundaries—and illustrate their antecedents and effects for project collaboration. These categories exemplify different responses to the threat of marginalization depending upon professionals’ perceptions of what the specific project called for. Our study provides important insights into boundary work practices emerging in the context of inter-organizational projects and how professionals adjust their claims-making to perceived opportunities, thereby triggering incremental as well as more radical changes in the professional role structures.","architects; boundary work; inter-organizational projects; professional role; role structures","en","journal article","","","","","","","","","","","Methodologie en Organisatie van Design","","",""
"uuid:97c8a397-4889-4e1f-8bbe-a599fc374ee6","http://resolver.tudelft.nl/uuid:97c8a397-4889-4e1f-8bbe-a599fc374ee6","Low Latency IoT/M2M Using Nano-Satellites","van 't Hof, Jos (Student TU Delft); Karunanithi, Visweswaran (TU Delft Electronics); Speretta, S. (TU Delft Space Systems Egineering); Verhoeven, C.J.M. (TU Delft Electronics); McCune, E.W. (TU Delft Electronics)","","2019","Nano-satellite IoT/M2M missions are gaining popularity in recent time. Various companies have launched their pilot missions last year in 2018 and all these companies intend to place a constellation in (V)LEO that can communicate with low power sensors on the ground (sometimes remote locations) and relay it back to the end-user who is monitoring these sensors. This paper discusses two possible architectures of using nano-satellites for low latency IoT/M2M, by presenting information such as, number of satellites needed, number of orbital planes needed and communication strategy. The first proposed architecture will comprise of a self-sustaining network of nano-satellites that communicate with low power, low data-rate sensors on the ground and relay the data to rest of the nano-satellites in the network using inter-satellite links, which is downlinked by a nano-satellite that is in the view of a ground station that is connected to IMT. The second proposed architecture will use nano-satellites to communicate with low power, low data-rate sensors on the ground and relay it to satellites that intend to provide internet from space (Mega-constellation). The internet constellations considered in this study for the second architecture are: Telesat’s constellation, SpaceX’s Starlink, OneWeb’s constellation, Astrome’s SpaceNet constellation and Audacy’s constellation. Using both these architectures, it can be seen that the latency can be reduced considerably.","(Mega-)constellation; Inter-satellite link; IoT; Latency; Nano-satellite","en","conference paper","IAC","","","","","","","","","","Electronics","","",""
"uuid:5b3d7b07-0e00-4512-a85a-527c869ee8b9","http://resolver.tudelft.nl/uuid:5b3d7b07-0e00-4512-a85a-527c869ee8b9","Integration of inter-terminal transport and hinterland rail transport","Hu, Q. (TU Delft Transport Engineering and Logistics); Wiegmans, B. (TU Delft Transport and Planning; University of Manitoba); Corman, Francesco (ETH Zürich); Lodewijks, Gabriel (University of New South Wales)","","2019","This paper investigates the problem of inter-terminal movements of containers and vehicles within a port area in order to achieve an integrated and effective transport within the port and towards the hinterland. Containers from different port terminals are first moved to a rail yard and then delivered to the hinterland by rail. To provide insights for stakeholders such as port authority and terminal operators into tactical planning problems, e.g., the coordination between terminals, railway timetable and train sizes, this paper proposes an optimization model describing the movement of containers and various vehicles between and inside terminals. The model aims at improving the container delivery from container terminals to the hinterland considering both railway hinterland transport and terminal handling operations. A network inspired by a real-life port area and its hinterland is used as a test case to test different components, i.e., inter-terminal transport connections, train formation, railway timetable. A rolling horizon framework is used to improve the computation efficiency in large transport demand cases. The result of the optimization helps in identifying the most promising features, namely, that more connections between terminals and a flexible outbound railway timetable could contribute to improving the integrated container transport performance.","Container terminal; Inter-terminal transport; Intermodal transport; Railway transport","en","journal article","","","","","","","","","","","Transport Engineering and Logistics","","",""
"uuid:c315d878-8528-494d-b718-b25df757ab8a","http://resolver.tudelft.nl/uuid:c315d878-8528-494d-b718-b25df757ab8a","A Comparative Study of Business-to-Government Information Sharing Arrangements for Tax Reporting","Kurnia, Rizky Amalia (Student TU Delft); Praditya, D. (TU Delft Information and Communication Technology); Janssen, M.F.W.H.A. (TU Delft Information and Communication Technology)","Dwivedi, Yogesh (editor); Ayaburi, Emmanuel (editor); Boateng, Richard (editor); Effah, John (editor)","2019","Having tax transparency is getting more important and enforced by more and more countries around the world. To deal with tax evasion, OECD has developed an Automatic Exchange of Information (AEOI) standard. The implementation of this standard differs among countries. In this study, we explore factors explaining the differences between two information sharing arrangements in implementing the AEOI standard. In both cases, the information sharing architecture and the accompanying governance arrangement are investigated. The findings of the exploratory study show that the differences are influenced by available IT capabilities, interoperability, trust among information sharing partners, power difference, inter-organizational relationship, and perceived benefits of implementing such arrangements. Ten propositions are derived explaining the differences which can be tested in further research.","AEOI; Business-to-government; E-government; Information sharing; Inter-organizational information sharing; Standardization; Tax report","en","conference paper","Springer","","","","","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.","","2019-12-19","","","Information and Communication Technology","","",""
"uuid:e02dba3f-4919-487a-ae42-c90eb9cd14cd","http://resolver.tudelft.nl/uuid:e02dba3f-4919-487a-ae42-c90eb9cd14cd","Steering the adoption of Standard Business Reporting for cross domain information exchange","Bharosa, Nitesh (TU Delft Information and Communication Technology); Hietbrink, Frans (Tax and Customs administration); Mosterd, Lars (Student TU Delft); Van Oosterhout, Ralf (Thauris, The Hague)","Hinnant, Charles C. (editor); Zuiderwijk, Anneke (editor)","2018","Over the years, several governments around the world have introduced a version of Standard Business Reporting (SBR) for information exchange with public agencies. Their main goals are to ease the reporting burden for businesses and the regulatory burden for government agencies. This paper takes a look at the adoption numbers in the Netherlands over multiple years. The objective of this paper is to analyse the adoption rates and explain them by revealing the steering instruments employed by government agencies looking to positive-ly influence SBR adoption. Our dataset consists of the total number of reports submitted using SBR towards the Tax Office, Chamber of Commerce and Industry, and the Education Executive Agency. Quantitative data analysis reveals different adoption rates and patterns in the aforementioned reporting chains. We found that adoption was positively influenced using a deliberate and fine-tuned set of steering instruments, including public-private governance, open communication and knowledge exchange, mandation, software community engagement and technical configuration (use of interfaces that match the sector specific reporting capabilities). When considering these steering instruments, policy makers and practitioners need to balance progressive standard setting and steady implementation.","Adoptions; B2G; Digital infrastructures; G2G; Inter-organisational information systems; Qualified information exchange; Standard business reporting; XBRL","en","conference paper","Association for Computing Machinery (ACM)","","","","","","","","","","Information and Communication Technology","","",""
"uuid:48fe61fd-3e8e-421c-b45a-48c829062e13","http://resolver.tudelft.nl/uuid:48fe61fd-3e8e-421c-b45a-48c829062e13","The Role of Universities in Inter-organizational Knowledge Collaborations","Haghighi Talab, A. (TU Delft Economics of Technology and Innovation); Scholten, V.E. (TU Delft Delft Centre for Entrepreneurship); van Beers, Cees (TU Delft Economics of Technology and Innovation)","","2018","Organizations collaborate with external actors in order to acquire knowledge resources they cannot develop internally for economic and/or technical reasons. Mode 2 and Triple Helix models have examined the role of different organizational types in collaborative creation and knowledge use. This paper is an empirical investigation on whether universities differ from business-oriented or industrial organization types with regard to the extent of their knowledge collaborations. Using SEM methodology, it demonstrates the role of universities in knowledge collaboration through a survey of 472 organizations in the 7th Framework Programme for Research and Technological Development of the European Commission, Energy theme (FP7-Energy). In line with the Triple Helix model, universities are found to exhibit more extensive knowledge collaboration than businesses. Also, between-university collaborations are found to be more extensive knowledge collaboration relationship types than between-business relationships. The findings imply that (1) publically funded consortia should be aware that universities are more conducive and hence more effective in inter-organizational knowledge collaboration networks than other organizational types, particularly compared to for-profit business organizations. Universities should be included in these consortia. (2) Business organizations that do not have an extensive relationship with universities need to reconsider their partner portfolio and extend the knowledge collaboration of their network by connecting to more universities.(3) Policymakers should not only involve academic organizations but also include groups of more than one university per consortium to enable between-university knowledge collaboration to boost collaborative knowledge exploration and exploitation of the consortia.","Inter-organizational; Knowledge collaboration; Triple Helix; University","en","journal article","","","","","","","","","","Delft Centre for Entrepreneurship","Economics of Technology and Innovation","","",""
"uuid:44062a1a-4159-4425-9aef-b7de5c78aea5","http://resolver.tudelft.nl/uuid:44062a1a-4159-4425-9aef-b7de5c78aea5","From dignity to security protocols: a scientometric analysis of digital ethics","Mahieu, R.L.P. (TU Delft Ethics & Philosophy of Technology); van Eck, Nees Jan (Universiteit Leiden); van Putten, D.C. (TU Delft Ethics & Philosophy of Technology); van den Hoven, M.J. (TU Delft Values Technology and Innovation)","","2018","Our lives are increasingly intertwined with the digital realm, and with new technology, new ethical problems emerge. The academic field that addresses these problems—which we tentatively call ‘digital ethics’—can be an important intellectual resource for policy making and regulation. This is why it is important to understand how the new ethical challenges of a digital society are being met by academic research. We have undertaken a scientometric analysis to arrive at a better understanding of the nature, scope and dynamics of the field of digital ethics. Our approach in this paper shows how the field of digital ethics is distributed over various academic disciplines. By first having experts select a collection of keywords central to digital ethics, we have generated a dataset of articles discussing these issues. This approach allows us to generate a scientometric visualisation of the field of digital ethics, without being constrained by any preconceived definitions of academic disciplines. We have first of all found that the number of publications pertaining to digital ethics is exponentially increasing. We furthermore established that whereas one may expect digital ethics to be a species of ethics, we in fact found that the various questions pertaining to digital ethics are predominantly being discussed in computer science, law and biomedical science. It is in these fields, more than in the independent field of ethics, that ethical discourse is being developed around concrete and often technical issues. Moreover, it appears that some important ethical values are very prominent in one field (e.g., autonomy in medical science), while being almost absent in others. We conclude that to get a thorough understanding of, and grip on, all the hard ethical questions of a digital society, ethicists, policy makers and legal scholars will need to familiarize themselves with the concrete and practical work that is being done across a range of different scientific fields to deal with these questions.","Data protection; Digital ethics’; GDPR; Inter-disciplinarity; Multi-disciplinarity; Privacy; Scientometrics; Term map","en","journal article","","","","","","","","","","Values Technology and Innovation","Ethics & Philosophy of Technology","","",""
"uuid:2b27bbe6-174b-4247-94f2-cf3ba6ac5a4c","http://resolver.tudelft.nl/uuid:2b27bbe6-174b-4247-94f2-cf3ba6ac5a4c","StimTrack: An open-source software for manual transcranial magnetic stimulation coil positioning","Ambrosini, Emilia (Politecnico di Milano; Scientific Institute of Lissone); Ferrante, Simona (Politecnico di Milano); van de Ruit, M.L. (TU Delft Biomechatronics & Human-Machine Control); Biguzzi, Stefano (Politecnico di Milano); Colombo, Vera Maria (Politecnico di Milano); Monticone, Marco (University of Cagliari); Ferriero, Giorgio (Scientific Institute of Lissone); Pedrocchi, Alessandra (Politecnico di Milano); Ferrigno, Giancarlo (Politecnico di Milano); Grey, Michael J. (University of East Anglia)","","2018","Background During Transcranial Magnetic Stimulation (TMS) experiments researchers often use a neuronavigation system to precisely and accurately maintain coil position and orientation. New method This study aimed to develop and validate an open-source software for TMS coil navigation. StimTrack uses an optical tracker and an intuitive user interface to facilitate the maintenance of position and orientation of any type of coil within and between sessions. Additionally, online access to navigation data is provided, hereby adding e.g. the ability to start or stop the magnetic stimulator depending on the distance to target or the variation of the orientation angles. Results StimTrack allows repeatable repositioning of the coil within 0.7 mm for translation and <1° for rotation. Stimulus-response (SR) curves obtained from 19 healthy volunteers were used to demonstrate that StimTrack can be effectively used in a typical experiment. An excellent intra and inter-session reliability (ICC > 0.9) was obtained on all parameters computed on SR curves acquired using StimTrack. Comparison with existing method StimTrack showed a target accuracy similar to that of a commercial neuronavigation system (BrainSight, Rogue Research Inc.). Indeed, small differences both in position (∼0.2 mm) and orientation (<1°) were found between the systems. These differences are negligible given the human error involved in landmarks registration. Conclusions StimTrack, available as supplementary material, is found to be a good alternative for commercial neuronavigation systems facilitating assessment changes in corticospinal excitability using TMS. StimTrack allows researchers to tailor its functionality to their specific needs, providing added value that benefits experimental procedures and improves data quality.","Accuracy; Coil positioning; Intra and inter-session reliability; Motor cortex; Motor evoked potential; Neuronavigation; Repeatability; Transcranial magnetic stimulation","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.","","2018-03-19","","","Biomechatronics & Human-Machine Control","","",""
"uuid:fe0c0a11-ef90-45cb-813f-ce1519773572","http://resolver.tudelft.nl/uuid:fe0c0a11-ef90-45cb-813f-ce1519773572","Understanding the effects of homeownership and regional unemployment levels on internal migration during the economic crisis in Spain","Palomares-Linares, Isabel (Universidad de Granada); van Ham, M. (TU Delft OLD Urban Renewal and Housing)","","2018","This paper seeks to understand better the effects of homeownership and regional unemployment levels on inter-provincial migration during the recent economic crisis in Spain. It uses rich individual-level microdata from the last two Spanish censuses (2001–2011) to study migration. The findings suggest that regional unemployment levels do not have a strong impact on internal migration in the period analyzed. However, homeownership is a key explanatory factor of immobility, which became more important in 2011 compared with 2001. This immobility effect of homeownership is stronger in depressed regions, which suggests that some people may be trapped in their dwellings, or the security of homeownership becomes essential when the structural conditions are unfavourable.","economic recession; homeownership; inter-provincial migration; unemployment rate","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.","","2019-03-20","","","OLD Urban Renewal and Housing","","",""
"uuid:14b17b45-f506-4e70-b261-12c73ab57a17","http://resolver.tudelft.nl/uuid:14b17b45-f506-4e70-b261-12c73ab57a17","Bayesian estimator for Logit Mixtures with inter- and intra-consumer heterogeneity","Becker, Felix (ETH Zürich); Danaf, Mazen (Massachusetts Institute of Technology); Song, Xiang (Massachusetts Institute of Technology); Atasoy, B. (TU Delft Transport Engineering and Logistics); Ben-Akiva, Moshe (Massachusetts Institute of Technology)","","2018","Estimating discrete choice models on panel data allows for the estimation of preference heterogeneity in the sample. While the Logit Mixture model with random parameters is mostly used to account for variation across individuals, preferences may also vary across different choice situations of the same individual. Up to this point, Logit Mixtures incorporating both inter- and intra-consumer heterogeneity are estimated with the classical Maximum Simulated Likelihood (MSL) procedure. The MSL procedure becomes computationally expensive with an increasing sample size and can be burdensome in the presence of a multi-modal likelihood function. We therefore propose a Hierarchical Bayes estimator for Logit Mixtures with both levels of heterogeneity. It builds on the Allenby-Train procedure, which considers only inter-consumer heterogeneity. To test the proposed procedures, we analyze how well the true patterns of heterogeneity are recovered in a simulation environment. Results from the Monte Carlo simulation suggest that falsely ignoring intra-consumer heterogeneity despite its presence in the data leads to biased estimates and a decreased goodness of fit. The latter is confirmed by a real-world example of explaining mode choices for GPS traces. We further show that the runtime of the proposed estimator is substantially faster than for the corresponding MSL estimator.","Hierarchical Bayes; Inter-consumer heterogeneity; Intra-consumer heterogeneity; Logit Mixture; Mixed Logit; Panel 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.","","2019-03-01","","","Transport Engineering and Logistics","","",""
"uuid:0c04626d-1bcb-4f14-a12c-261f11b97794","http://resolver.tudelft.nl/uuid:0c04626d-1bcb-4f14-a12c-261f11b97794","Multi-GNSS PPP-RTK: Mixed-receiver network and user scenarios","Teunissen, P.J.G. (TU Delft Mathematical Geodesy and Positioning; Curtin University); Khodabandeh, A. (Curtin University); Zhang, B. (Curtin University)","Freymueller, Jeffrey T. (editor); Sánchez, Laura (editor)","2018","In this contribution, we present full-rank observation equations of the network and user receivers, of mixed types, through an application of S-system theory. We discuss the important roles played by the inter system biases (ISBs), and we show how the three-component structure of PPP-RTK is affected by the inclusion of the ISBs as extra parameters in the model.","GNSS; Inter system bias (ISB); ISB look-up table; PPP-RTK","en","conference paper","Springer","","","","","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.","","2018-07-01","","","Mathematical Geodesy and Positioning","","",""
"uuid:e77543bd-ab87-4a2a-8a89-1d502ad1440c","http://resolver.tudelft.nl/uuid:e77543bd-ab87-4a2a-8a89-1d502ad1440c","The First (Beer) Living Lab: Learning to Sustain Network Collaboration for Digital Innovation","Frößler, Frank (University College Dublin); Rukanova, B.D. (TU Delft Information and Communication Technology); Klein, Stefan (University of Münster); Higgins, A. (University College Dublin); Tan, Y. (TU Delft Information and Communication Technology); Kelly, S (University College Dublin)","Riemer, Kai (editor); Schellhammer, Stefan (editor); Meinert, Michaela (editor)","2018","The Beer Living Lab was the first of a series of living labs established to analyse and improve complex cross-border trade and logistics challenges using innovative information technology. Unlike stable inter-firm networks where roles are formal and explicit, role taking and role assigning in the Beer Living Lab was highly dynamic. Although project deliverables were formally assigned, in practice responsibilities emerged as a result of actors’ own initiative or as a result of negotiation and sense-making. Even leadership behaviour shifted throughout the various stages of the initiative. The practice of knowledge broking and cultivating a close working relationship with the operational manager emerged as crucial for creating and sustaining the social network which in turn stabilised the hybrid network organisation. We discover (yet again) the key practices of knowledge brokers and the necessity for social involvement in overcoming discontinuities within organisation networks.","Inter-organisational networks; Sense making; Network management; Living-labs; Knowledge broker","en","book chapter","Springer","","","","","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.","","2019-01-20","","","Information and Communication Technology","","",""
"uuid:46a4329f-5d76-41ca-aecd-71c855908bde","http://resolver.tudelft.nl/uuid:46a4329f-5d76-41ca-aecd-71c855908bde","Empirical Modelling of Inter-organizational Knowledge Collaboration","Haghighi Talab, A. (TU Delft Economics of Technology and Innovation)","van Beers, Cees (promotor); Scholten, V.E. (copromotor); Delft University of Technology (degree granting institution)","2017","Open innovation, knowledge co-creation, and research joint ven-tures, unified under the term 'inter-organizational knowledge collaboration', are discussed in various fields of innovation man-agement to ultimately shape inno-vation strategy of the organiza-tions and the innovation policy.
Several ongoing debates are crucial in the allocation of resources and division of labor with regards to the innovation system: industries vs. universities, who are the salient actors of the innovation system? Death of distance vs. geographical boundedness, does distance mat-ter? Network cohesion vs. struc-tural holes, where in the network is more fertile for innovation?
This book, discussing these de-bates, intends to direct the innovation strategy and policy.
The project combines specific landscape conditions of a site with the interaction of visitors and the dynamics of onsite construction, exploring the role of spatial designers in situated, interactive projects.
Students: Bella Bluemink, Eva Ventura, Eva Willemsen, Federica Sanchez, Ge Hong, Ilya Tasioula, Jan Gerk de Beer, Joey Liang, Lukas Kropp, Maël Vanhelsuwé, IVIax Einerf IVlichelle Siemerink, Qingyun Lin, Timothy Radhitya Djagiri.Yao Lu.
Tutors chair of Landscape Architecture: D.Piccinini and R.van der Velde","Landscape Architecture; On Site; art; interation; place; perception","en","book","Delft University of Technology","","","","","","","","","","Landscape Architecture","","",""
"uuid:8f20a7b4-8252-47db-b284-384b7c56a85a","http://resolver.tudelft.nl/uuid:8f20a7b4-8252-47db-b284-384b7c56a85a","Inter-municipal cooperation, economies of scale and cost efficiency: an application of stochastic frontier analysis to Dutch municipal tax departments","Niaounakis, T.K. (TU Delft Economics of Technology and Innovation); Blank, J.L.T. (TU Delft Economics of Technology and Innovation; Erasmus Universiteit Rotterdam)","","2017","Inter-municipal cooperation is increasingly popular in European countries. Saving cost is a key motivation. This paper analyses the relation between inter-municipal cooperation and cost efficiency among Dutch municipal tax departments between 2005 and 2012. Motivated by the notion that cost savings are ascribed to scale economies, the relation between cooperation and cost is modelled explicitly through scale. The size of the cooperation is incorporated as a determinant of cost efficiency. The results indicate that inter-municipal cooperation can contribute to reducing cost and that the relation can be explained by scale. Municipalities or cooperations sized around 10,000 inhabitants are estimated up to 30% inefficient. At 60,000 inhabitants, the benefits of scaling are largely exhausted. Other than through scale, municipalities that cooperate are not estimated to operate significantly more or less efficient.","efficiency analysis; Inter-municipal cooperation; local government; scale economies","en","journal article","","","","","","","","","","","Economics of Technology and Innovation","","",""
"uuid:03f18640-79f5-4fc1-8c86-8b9ae63b7949","http://resolver.tudelft.nl/uuid:03f18640-79f5-4fc1-8c86-8b9ae63b7949","Optimizing Silicon Oxide Embedded Silicon Nanocrystal Inter-particle Distances","van Sebille, M. (TU Delft Photovoltaic Materials and Devices); Allebrandi, J.S. (TU Delft Photovoltaic Materials and Devices); Quik, J. (TU Delft Photovoltaic Materials and Devices); van Swaaij, R.A.C.M.M. (TU Delft Photovoltaic Materials and Devices); Tichelaar, F.D. (TU Delft QN/Zandbergen Lab); Zeman, M. (TU Delft Electrical Sustainable Energy)","","2016","We demonstrate an analytical method to optimize the stoichiometry and thickness of multilayer silicon oxide films in order to achieve the highest density of non-touching and closely spaced silicon nanocrystals after annealing. The probability of a nanocrystal nearest-neighbor distance within a limited range is calculated using the stoichiometry of the as-deposited film and the crystallinity of the annealed film as input parameters. Multiplying this probability with the nanocrystal density results in the density of non-touching and closely spaced silicon nanocrystals. This method can be used to estimate the best as-deposited stoichiometry in order to achieve optimal nanocrystal density and spacing after a subsequent annealing step.","Inter-particle distance; Silicon nanocrystal; Silicon oxide; Spacing; Stoichiometry","en","journal article","","","","","","","","","","Electrical Sustainable Energy","Photovoltaic Materials and Devices","","",""
"uuid:3f86bf04-c6af-486f-b972-bd228d84ebed","http://resolver.tudelft.nl/uuid:3f86bf04-c6af-486f-b972-bd228d84ebed","On the anatomy of nearshore sandbars: A systematic exposition of inter-annual sandbar dynamics","Walstra, D.J.R. (TU Delft Coastal Engineering)","Stive, M.J.F. (promotor); Ruessink, BG (promotor); Reniers, A.J.H.M. (promotor); Delft University of Technology (degree granting institution)","2016","Nearshore sandbars have a lifetime of many years, during which they exhibit cyclic, offshore directed behaviour with strong alongshore coherence. A bar is generated near the shoreline and grows in height and width while migrating offshore, before finally decaying at the seaward limit of the surf zone. It may take 10 to 15 years for a bar to exhibit this cycle. Four to five bars may occur simultaneously within a cross-shore bed profile. Alongshore variations in cross-shore bar position and bar amplitude are commonly observed. A strong or abrupt alongshore variability is referred to as a bar switch. At large spatial scales, the inter-annual bar dynamics may vary considerably across sites with very similar environmental settings. In particular, the bar cycle return period (Tr, i.e. the duration between two successive bar decay events) may differ by a factor of three to four. This type of change in Tr appears to be always present in time and is characterized as a persistent bar switch. At smaller (kilometer) scales, bar switches typically occur in areas with similar Tr-values on both sides of a bar switch and occasionally disappear when the bars re-attach. These are characterized as non-persistent bar switches. The assimilation of shoreface nourishments into the coastal system involves a strong interaction with the pre-existing sandbar system. Typically the placement of a shoreface nourishment just seaward of an outer bar reverses the bar cycle temporalily, inducing a landward migration of the bar system. The shoreface nourishment becomes absorbed in the coastal system as the new outer bar. At the distal ends of the shoreface nourishment bar switches often manifest, owing to a distinct difference in the bar migration cycle phase that is induced. Given the importance of the bar-nourishment interaction, an improved understanding of the nearshore bar dynamics is expected to improve the efficacy of shoreface nourishments. Furthermore, the long-term evolution of the nearshore barred profiles is generally considered indicative of the quality of the modelling for the response of the entire nearshore coastal system. Therefore, the ability to perform reliable and robust a-priori, long-term predictions has broad societal relevance in view of anticipated adverse impacts of climate change and sea level rise on the stability of coasts worldwide. Until now the anatomy of the nearshore sandbars has primarily been studied using field data. Although these studies have provided insight into how the geometric bar parameters respond to the external forcings, no comprehensive conceptual framework is available that explains the full life cycle of a sandbar and its associated characteristics. The overarching objective of this study is to elucidate the anatomy of the inter-annual bar morphology using a combined data and model approach. This overarching objective is in turn devolved into three objectives aiming to understand key features of bar morphology and a further objective to enable a comprehensive modelling approach based on the acquired insights. The latter objective involves the development of an input-reduction framework for advanced process-based forward modelling of the inter-annual bar morphology.
1) To elucidate the morphodynamic processes that result in cross-shore transient sandbar amplitude responses (i.e. the transition from bar growth in the intertidal and across surf zone to sandbar decay at the seaward edge of the surf zone). 2) To establish the role of cross-shore processes in non-persistent bar switches. 3) To identify the dominant environmental variables and the associated mechanisms that govern the bar cycle return period. 4) To develop an input-reduction framework to enable the application of state-of-the-art process based forward area models to simulate the multi-annual bar behaviour and nearshore morphology.
A comprehensive study approach is adopted in which observations of the nearshore morphology are combined with detailed forward modeling of the bar dynamics at Noordwijk (The Netherlands) utilizing wave and waterlevel observations as boundary conditions. The Noordwijk model acts as a reference for additional simulations at Egmond (The Netherland) and at Hasaki (Japan) to address the specific characteristics of the nearshore sandbar morphodynamics as outlined above.
The transient cross-shore bar amplitude response Based on a three-year hindcast of a bar cycle at Noordwijk (Netherlands) and on additional synthetic runs using a wave-averaged cross-shore process model, the dominant mechanisms that govern the bar amplitude growth and decay during net inter-annual offshore migration are identified. The bar amplitude response is particularly sensitive to the water depth above the bar crest, hXb, and the angle of wave incidence, θ. These variables largely control the amount of waves breaking on the bar and the strength and cross-shore distribution of the associated longshore current. The longshore current has its maximum landward of the bar crest, inducing additional stirring of sediment on the landward bar slope and trough. The enhanced sediment concentration in the trough region shifts the cross-shore transport peak landward of the bar crest, forcing bar amplitude growth during offshore migration. For increased hXb-values wave breaking becomes less frequent, reducing the influence of the longshore current on sediment stirring. Therefore, the resulting dominance of the cross-shore current results in a sediment transport peak at, or just seaward of, the bar crest causing bar amplitude decay. All four types of bar response (viz. all combinations of onshore/offshore migration and bar amplitude growth/decay) can occur for a single wave height and wave period combination, depending on hXb and θ. Additional hindcast runs in which the wave direction was assumed time-invariant confirmed that hXb and θ largely control the transient bar amplitude response.
The mechanics of non-persistent bar switches Intra-site alongshore variability is greatest when bars display km-scale disruptions, indicative of a distinct alongshore phase shift in the bar cycle. An outer bar is then, for example, attached to an inner bar, referred to as a non-persistent bar switch. This large-scale alongshore variability is investigated by applying the reference model at 24 transects along a 6 km section of the barred beach at Noordwijk (The Netherlands). When alongshore variability is limited, the model predicts that the bars migrate offshore at approximately the same rate (i.e. the bars remain in phase). Only under specific bar configurations with high wave-energy levels is an increase in the alongshore variability predicted. This suggests that cross-shore processes may trigger a switch in the case of specific antecedent morphological configurations combined with storm conditions. It is expected that three-dimensional (3D) flow patterns augment the alongshore variability in such instances. In contrast to the observed bar behaviour, predicted bar morphologies on either side of a switch remain in different phases, even though the bars are occasionally located at a similar cross-shore position. In short, the 1D profile model is not able to remove a bar switch. This data-model mismatch suggests that 3D flow patterns are key to the dissipation of bar switches.
The mechanics of persistent bar switches and the bar cycle return period To date, data-analytic studies have had only partial success in explaining differences in Tr, establishing at best weak correlations to local environmental characteristics. In the present approach the process-based profile reference model is utilized to investigate the non-linear interactions between the hydrodynamic forcing and the morphodynamic profile response for two sites. Despite strong similarity in environmental conditions, the sites at Noordwijk and Egmond on the Holland coast exhibit distinctly different Tr values. The detailed comparison of modelling results enables a consistent investigation of the role of specific parameters at a level of detail that could not have been achieved from observations alone, and provides insights into the mechanisms that govern Tr. The results reveal that the bed slope at the barred zone is the most important parameter governing Tr. As a bar migrates further offshore, a steeper slope results in a stronger relative increase in hXb which reduces wave breaking and in turn reduces the offshore migration rate. The deceleration of the offshore migration rate as the bar moves to deeper water - the morphodynamic feedback loop - contrasts with the initial enhanced offshore migration behaviour of the bar. The initial behaviour is determined by the intense wave breaking associated with the steeper profile slope. These mechanisms explain the counter-intuitive observations at Egmond where Tr is significantly longer than at Noordwijk despite Egmond having the more energetic wave climate which typically reduces Tr.
Input reduction for inter-annual advanced forward model applications In order to avoid excessively long computation times, input reduction is imperative for the application of advanced forward morphodynamic area models to consider long-term (>years) predictions. Here, an input reduction framework for wave-dominated coastal settings is introduced. The framework comprises 4 steps, viz. (1) the selection of the duration of the original (full) time series of wave forcing, (2) the selection of the representative wave conditions, (3) the sequencing of these conditions, and (4) the time span after which the sequence is repeated. In step (2), the chronology of the original series is retained, while that is no longer the case in steps (3) and (4). We apply the framework to two different sites (Noordwijk, The Netherlands and Hasaki, Japan) with multiple nearshore sandbars but contrasting long-term offshore-directed behaviour: at Noordwijk the offshore migration is gradual and not coupled to individual storms, while at Hasaki the offshore migration is more episodic, and wave chronology appears to control the long-term evolution. The performance of the model with reduced wave climates is compared with a simulation with the actual (full) wave-forcing series. It is demonstrated that input reduction can dramatically affect long-term predictions, to such an extent that the main characteristics of the offshore bar cycle are no longer reproduced. This was the case at Hasaki, in particular, where all synthetic series that no longer retain the initial chronology (steps 3 and 4) lead to rather unrealistic long-term simulations. At Noordwijk, synthetic series can result in realistic behaviour, provided that the time span after which the sequence is repeated is not too large; the reduction of this time span has the same positive effect on the simulation as increasing the number of selected conditions in step 2. It is further demonstrated that, although storms result in the largest morphological change, conditions with low to intermediate wave energy must be retained to obtain realistic long-term sandbar behaviour. The input-reduction framework must be applied in an iterative fashion to obtain a reduced wave climate that is able to simulate long-term sandbar behaviour sufficiently accurately within an acceptable computation time. These results imply that it is essential to consider input reduction as an intrinsic part of any model set-up, calibration and validation effort. The study outcomes indicate clearly that a relatively simple model can be utilized to study the highly non-linear interaction between the nearshore hydrodynamics and morphology in great detail. This was achieved through carefully designed numerical experiments in which the influence of a specific process or environmental variable was isolated and identified. Although the model only considers cross-shore processes, the numerical experiments generated new insights into the importance of 3D processes under particular morphological conditions of the nearshore barred profiles. Even though the model was successfully calibrated at Noordwijk, the application at Egmond showed a significantly reduced predictive capacity. The model was able to reproduce the main characteristics of the inter-annual bar morphodynamics, but the bar cycle return period was under-estimated by about 30%. This suggests that the model can capture trends fairly well, but is unable to produce accurate absolute predictions - a finding that has broader implications. As stated earlier, accurate predictions of the long-term evolution of the nearshore barred profiles are generally considered indicative of the quality of the modelling of the entire nearshore coastal system. Consequently, further improvement of morphodynamic process-based models, particularly for the nearshore zone, constitutes a major research priority.","Sandbars; Bar decay; Process based modeling; Unibest-TC; Cyclic bar behavior; Input reduction; Input filtering; Morphodynamic modeling; alongshore variability; bar switching; Noordwijk; Argus; Jarkus; morphodynamic feedback loop; Egmond; inter-annual bar dynamics","en","doctoral thesis","","978-94-6186-647-9","","","","","","","","","Coastal Engineering","","",""
"uuid:b59728ef-e225-466d-b487-e601cbd5f606","http://resolver.tudelft.nl/uuid:b59728ef-e225-466d-b487-e601cbd5f606","On the Intersite Variability in Inter-Annual Nearshore Sandbar Cycles","Walstra, D.J.R. (TU Delft Coastal Engineering; Deltares); Wesselman, Daan (Universiteit Utrecht); van der Deyl, Eveline (Universiteit Utrecht); Ruessink, BG (Universiteit Utrecht)","","2016","Inter-annual bar dynamics may vary considerably across sites with very similar environmental settings. In particular, the variability of the bar cycle return period (Tr) may differ by a factor of 3 to 4. To date, data studies are only partially successful in explaining differences in Tr, establishing at best weak correlations to local environmental characteristics. Here, we use a process-based forward model to investigate the non-linear interactions between the hydrodynamic forcing and the morphodynamic profile response for two sites along the Dutch coast (Noordwijk and Egmond) that despite strong similarity in environmental conditions exhibit distinctly different Tr values. Our exploratory modeling enables a consistent investigation of the role of specific parameters at a level of detail that cannot be achieved from observations alone, and provides insights into the mechanisms that govern Tr. The results reveal that the bed slope in the barred zone is the most important parameter governing Tr. As a bar migrates further offshore, a steeper slope results in a stronger relative increase in the water depth above the bar crest which reduces wave breaking and in turn reduces the offshore migration rate. The deceleration of the offshore migration rate as the bar moves to deeper water—the morphodynamic feedback loop—contrasts with the initial enhanced offshore migration behavior of the bar. The initial behavior is determined by the intense wave breaking associated with the steeper profile slope. This explains the counter-intuitive observations at Egmond where Tr is significantly longer than at Noordwijk despite Egmond having the more energetic wave climate which typically reduces Tr.","morphodynamic feedback loop; Egmond; Noordwijk; inter-annual bar dynamics; process based modeling; Unibest-TC; sandbars; bar switch; morphodynamic modeling; cyclic bar behavior; Jarkus","en","journal article","","","","","","","","","","","Coastal Engineering","","",""
"uuid:6020a676-5cfd-4191-83db-67be240dfcc2","http://resolver.tudelft.nl/uuid:6020a676-5cfd-4191-83db-67be240dfcc2","Predictive path following with arrival time awareness for waterborne AGVs","Zheng, H. (TU Delft Transport Engineering and Logistics); Negenborn, R.R. (TU Delft Transport Engineering and Logistics); Lodewijks, G. (TU Delft Transport Engineering and Logistics)","","2016","Large ports are seeking innovative logistical ways to improve their competitiveness world-wide. This article proposes waterborne AGVs, inspired by conventional automated guided vehicles and autonomous surface vessels, for transport over water. A predictive path following with arrival time awareness controller is proposed for such waterborne AGVs. The controller is able to achieve smooth tracking and energy efficiency with arrival time awareness for transport oriented applications. Tracking errors are conveniently formulated with vessel dynamics modeled in connected reference path coordinate systems and a coordinate transformation at switching coordinate systems. Binary decision variables and logic constraints based on an along-track state are proposed for modeling switches in the framework of Model Predictive Control (MPC) so that overshoots are avoided. Moreover, timing-aware along-track references are generated by a two-level double integrator scheme. The lower level is embedded in online MPC optimizations for smooth tracking. The higher level solves a mixed-integer quadratic programming problem considering distance-to-go and time-to-go before each MPC optimization. References over the next prediction horizon are generated being aware of the requirements on arrival time. Furthermore, successive linearizations of nonlinear vessel dynamics about a shifted previous optimal system trajectory are implemented to maintain a trade-off between computational complexity and optimality. Simulation results of two industrially relevant Inter Terminal Transport case studies illustrate the effectiveness of the proposed modeling and control design for waterborne AGVs","Model predictive control; Waterborne AGVs; Inter terminal transport; Path following; Arrival time awareness","en","journal article","","","","","","","Campus only","","","","Transport Engineering and Logistics","","",""
"uuid:89684bc7-3c43-4d7d-8238-a5503e929adb","http://resolver.tudelft.nl/uuid:89684bc7-3c43-4d7d-8238-a5503e929adb","Overcoming barriers to institutional integration in European second-tier urban regions","Viseu Cardoso, Rodrigo (TU Delft OLD Urban and Regional Development)","","2016","Within the debates about the socio-economic advantages of cohesive urban regions, several barriers to institutional integration are said to exist, especially when a metropolitan government is absent and integration relies on inter-municipal cooperation. Some barriers are associated with different urban region structures, such as the asymmetric power relations and sociocultural contrasts between municipalities in systems with dominant core cities, or the lack of a leading city to overcome fragmentation and provide a shared identity in polycentric urban regions (PURs). This paper investigates whether urban regions formed around second-tier cities, whose features depart from both dominant core and PUR models, are able to mitigate these barriers when pursuing integration strategies. The analysis relies on interviews with municipal leaders in three representative European case studies, examining how they perceive the barriers to inter-municipal relations in second-tier urban regions. The findings show that perceptions vary not only between regions, with the three cases following different trajectories of integration, but also within regions, according to the geographical and socio-economic context of municipalities and the legacy of past relations. In general, barriers to integration are not minimized without explicit efforts to rebalance power relations, approach political cultures, mobilize core city leadership and develop a metropolitan identity.","institutional integration; inter-municipal cooperation; metropolitan identity; Second-tier cities; urban regions","en","journal article","","","","","","Accepted Author Manuscript","","2018-05-01","","","OLD Urban and Regional Development","","",""
"uuid:b0d1b7fd-fded-4e7b-89a9-fe069d75973c","http://resolver.tudelft.nl/uuid:b0d1b7fd-fded-4e7b-89a9-fe069d75973c","Characterization of multi-GNSS between-receiver differential code biases using zero and short baselines","Zhang, B.; Teunissen, P.J.G.","","2015","Care should be taken to minimize adverse impact of receiver differential code biases (DCBs) on global navigation satellite system (GNSS)-derived ionospheric parameters. It is therefore of importance to ascertain the intrinsic characteristics of receiver DCBs, preferably in the context of new-generation GNSS. In this contribution, we present a method that enables time-wise retrieval of between-receiver DCBs (BR-DCBs) from dual-frequency, code-only measurements collected by a pair of co-located receivers. This method is applicable to the US GPS as well as to a new set of GNSS constellations including the Chinese BeiDou, the European Galileo and the Japanese QZSS. With the use of this method, we determine the multi-GNSS BR-DCB time-wise estimates covering a time period of up to 2 years (January 2013–March 2015) with a 30-s time resolution for five receiver-pairs (four zero and one short baselines). For the BR-DCB time-wise estimates pertaining to an arbitrary receiver-pair and constellation, we demonstrate their promising intraday stability by means of statistical hypothesis testing. We also find that the BeiDou BR-DCB daily weighted average (DWA) estimates show a dependence on satellite type, in particular for receiver-pairs of mixed types. Finally, we demonstrate that long-term variability in BR-DCB DWA estimates can be closely associated with hardware temperature variations inside the receivers.","global navigation satellite system (GNSS); total electron content (TEC); between-receiver differential code bias (BR-DCB); BeiDou code inter-satellite-type-bias (ISTB)","en","journal article","Springer","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:00c8b531-6f36-4489-9b2a-7162908e7f5e","http://resolver.tudelft.nl/uuid:00c8b531-6f36-4489-9b2a-7162908e7f5e","Beyond informality: Traders as space experts in their own informal settlements","Mohamed, A.A.; Van Nes, A.; Salheen, M.A.","","2015","The spatial layout of built environments influences the distribution of commercial activities. As literature has shown, commercial activities can enhance the process of urban consolidation of informal areas (Hillier et al, 2000; Shafiei, 2007). The purpose of this paper is to investigate the correlation between spatial factors and the distribution of internal and edge commercial land use by applying new methodological means, such as a combined space syntax analysis of the street network with Inter-visibility (van Nes & López, 2010), and statistical analysis of the economic issues and band analyses. The cases used in this study are three informal areas in Cairo: Ezbet Bekhit, Ezbet Al-Nasr and Abu Qatada. These settlements are selected because they are predominantly self-grown and have not been influenced by city plans or land use regulations. This research attempts to underpin the following questions: Are the distribution and rate of commercial activities mainly driven by the local spatial composition of the area itself? Or, is it more related to how the settlements are embedded in the overall structure of the city? As it turns out, this research has demonstrated in detail that the distribution of commercial activities takes place on the plots that are located along the spatially most integrated, most distributed and most inter-visible parts of the neighbourhoods in relationship to the whole of the city. The results of this empirical study contribute to further understanding of a theory of an optimal distribution of plots, in which effective land use is defined as an interaction of two core factors: inter-visibility and spatial accessibility. This two-variable approach can be used strategically as a tool to guide the regeneration of informal settlements and transferring economic integration to deprived areas of the city.","space syntax; commercial activities; informal aereas; urban consolidation; inter-visibility","en","conference paper","Space Syntax Laboratory,The Bartlett School of Architecture, UCL","","","","","","","","Architecture and The Built Environment","Urbanism","","","",""
"uuid:4ec5b98a-cd41-40ce-8a57-58f3de8b13fa","http://resolver.tudelft.nl/uuid:4ec5b98a-cd41-40ce-8a57-58f3de8b13fa","Inter Terminal Transport System Design Using Conveyor Belts for the Port of Rotterdam (summary)","Sadeghi, H.","Lodewijks, G. (mentor)","2014","","Port; Inter Terminal transport; belt conveyor; experimental simulation","","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:1a00d9b0-ab4f-4909-8fc0-e3eaf6b4e991","http://resolver.tudelft.nl/uuid:1a00d9b0-ab4f-4909-8fc0-e3eaf6b4e991","Inter Terminal Transport System Design Using Conveyor Belts for the Port of Rotterdam","Sadeghi, H.","Lodewijks, G. (mentor)","2014","","Port; Inter Terminal transport; belt conveyor; experimental simulation","","master thesis","","","","","","","","2019-11-27","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Transport Engineering and Logistics","","",""
"uuid:10e5599c-8679-4192-a6bf-20366483bdb2","http://resolver.tudelft.nl/uuid:10e5599c-8679-4192-a6bf-20366483bdb2","Extended stakeholder interaction analysis: Innovative smart living design cases","Solaimani, S.; Guldemond, N.A.; Bouwman, W.A.G.A.","","2013","In order to become more innovative, companies that operate in the Smart Living domain increasingly initiate and participate in networked business environments that transcend industry boundaries. Inter-organizational collaboration is often characterized by conflicting strategic interests and incoherent operational business processes and procedures. Although many scholars and practitioners use stakeholder analysis to gain insight into the actors’ relationships and interactions, existing literature on stakeholder analysis focuses mainly on high-level strategic analysis, often limited to a conceptual and static understanding of stakeholder interests. In this paper, it is argued that a ‘true’ understanding of stakeholders can be achieved by looking at their interactions and interdependencies at a more detailed level. This study uses a conceptual framework from the service innovation and business model domain, the VIP framework, to extend stakeholder analysis by including an analysis of their dynamic interactions and processes. The qualitative evaluation of the framework’s application in illustrative design cases shows that this extension provides additional insights into stakeholders, and their potential operational conflicts and critical dependencies. By making these conflicts and interdependencies explicit, products and services are potentially easier to implement and commercialize.","stakeholder analysis; business models; networkedbusiness; inter-organizational systems smart living","en","journal article","Springer","","","","","","","","Technology, Policy and Management","Engineering, Systems and Services","","","",""
"uuid:5f6145b0-09a4-4125-8221-7c788ce823cf","http://resolver.tudelft.nl/uuid:5f6145b0-09a4-4125-8221-7c788ce823cf","Dynamic stakeholder interaction analysis: Innovative smart living design cases","Solaimani Kartalaei, H.; Guldemond, N.A.; Bouwman, W.A.G.A.","","2013","In order to become more innovative, companies that operate in the Smart Living domain increasingly initiate and participate in networked business environments that transcend industry boundaries. Inter-organizational collaboration is often characterized by conflicting strategic interests and incoherent operational business processes and procedures. Although many scholars and practitioners use stakeholder analysis to gain insight into the actors’ relationships and interactions, existing literature on stakeholder analysis focuses mainly on high-level strategic analysis, often limited to a conceptual and static understanding of stakeholder interests. In this paper, it is argued that a ‘true’ understanding of stakeholders can be achieved by looking at their interactions and interdependencies at a more detailed level. This study uses a conceptual framework from the service innovation and business model domain, the VIP framework, to extend stakeholder analysis by including an analysis of their dynamic interactions and processes. The qualitative evaluation of the framework’s application in illustrative design cases shows that this extension provides additional insights into stakeholders, and their potential operational conflicts and critical dependencies. By making these conflicts and interdependencies explicit, products and services are potentially easier to implement and commercialize.","stakeholder analysis; business models; networkedbusiness; inter-organizationalsystems smart living","en","journal article","Springer","","","","","","","","Technology, Policy and Management","Infrastructures, Systems and Services","","","",""
"uuid:4b8f5908-c07c-488d-b2a7-5453be5e46f9","http://resolver.tudelft.nl/uuid:4b8f5908-c07c-488d-b2a7-5453be5e46f9","BeiDou inter-satellite-type bias evaluation and calibration for mixed receiver attitude determination","Nadarajah, N.; Teunissen, P.J.G.; Raziq, N.","","2013","The Chinese BeiDou system (BDS), having different types of satellites, is an important addition to the ever growing system of Global Navigation Satellite Systems (GNSS). It consists of Geostationary Earth Orbit (GEO) satellites, Inclined Geosynchronous Satellite Orbit (IGSO) satellites and Medium Earth Orbit (MEO) satellites. This paper investigates the receiver-dependent bias between these satellite types, for which we coined the name “inter-satellite-type bias” (ISTB), and its impact on mixed receiver attitude determination. Assuming different receiver types may have different delays/biases for different satellite types, we model the differential ISTBs among three BeiDou satellite types and investigate their existence and their impact on mixed receiver attitude determination. Our analyses using the real data sets from Curtin’s GNSS array consisting of different types of BeiDou enabled receivers and series of zero-baseline experiments with BeiDou-enabled receivers reveal the existence of non-zero ISTBs between different BeiDou satellite types. We then analyse the impact of these biases on BeiDou-only attitude determination using the constrained (C-)LAMBDA method, which exploits the knowledge of baseline length. Results demonstrate that these biases could seriously affect the integer ambiguity resolution for attitude determination using mixed receiver types and that a priori correction of these biases will dramatically improve the success rate.","Global Navigation Satellite Systems (GNSS); BeiDou system (BDS); inter-satellite-type biases; attitude determination; multivariate constrained integer leastsquares( MC-LAMBDA); carrier phase ambiguity resolution","en","journal article","MDPI","","","","","","","","Civil Engineering and Geosciences","Geoscience & Remote Sensing","","","",""
"uuid:193187c0-04e3-48d2-8059-d95a4653a144","http://resolver.tudelft.nl/uuid:193187c0-04e3-48d2-8059-d95a4653a144","The last will be first: Water transfers from agriculture to cities in the Pangani river basin, Tanzania","Komakech, H.C.; Van der Zaag, P.; Koppen, B.","","2012","Water transfers to growing cities in sub-Sahara Africa, as elsewhere, seem inevitable. But absolute water entitlements in basins with variable supply may seriously affect many water users in times of water scarcity. This paper is based on research conducted in the Pangani river basin, Tanzania. Using a framework drawing from a theory of water right administration and transfer, the paper describes and analyses the appropriation of water from smallholder irrigators by cities. Here, farmers have over time created flexible allocation rules that are negotiated on a seasonal basis. More recently the basin water authority has been issuing formal water use rights that are based on average water availability. But actual flows are more often than not less than average. The issuing of state-based water use rights has been motivated on grounds of achieving economic efficiency and social equity. The emerging water conflicts between farmers and cities described in this paper have been driven by the fact that domestic use by city residents has, by law, priority over other types of use. The two cities described in this paper take the lion’s share of the available water during the low-flow season, and at times over and above the permitted amounts, creating extreme water stress among the farmers. Rural communities try to defend their prior use claims through involving local leaders, prominent politicians and district and regional commissioners. Power inequality between the different actors (city authorities, basin water office, and smallholder farmers) played a critical role in the reallocation and hence the dynamics of water conflict. The paper proposes proportional allocation, whereby permitted abstractions are reduced in proportion to the expected shortfall in river flow, as an alternative by which limited water resources can be fairly allocated. The exact amounts (quantity or duration of use) by which individual user allocations are reduced would be negotiated by the users at the river level.","inter-sectoral allocation; irrigation; priority allocation; urban water demand; water conflict; water right; water scarcity","en","journal article","","","","","","","","","Civil Engineering and Geosciences","Water Management","","","",""
"uuid:1c2897fd-ad41-414a-8344-171491f63d3b","http://resolver.tudelft.nl/uuid:1c2897fd-ad41-414a-8344-171491f63d3b","Relative state estimation and observability for formation flying satellites in the presence of sensor noise","Maessen, D.C.; Gill, E.K.A.","","2010","This paper presents an investigation into the relative state estimation and observability for two formation flying satellites using two different relative navigation sensor sets. The first set consists out of a transmitter antenna on one satellite and a single receiver antenna on the other satellite to measure the inter-satellite range using a radiofrequency ranging signal. The second set uses three receiver antennas to measure multiple ranges, effectively providing angular information. It is derived in the paper that for the more complete sensor set, the error in the estimation of the relative state is a function of the pseudorange error, the inter-satellite distance, and the receiver antenna baselines. By varying these variables, conditions are found for which the observations obtained using the first sensor set result in relative state estimation and observability comparable to those obtained with the more complete sensor set. This offers potential reductions in cost and complexity for certain mission scenarios.","formation flying; inter-satellite ranging; noise; estimation; observability","en","conference paper","International Astronautical Federation","","","","","","","","Aerospace Engineering","Space Engineering","","","",""
"uuid:9ec7bc4b-7f08-408c-9e26-ffe6436215f1","http://resolver.tudelft.nl/uuid:9ec7bc4b-7f08-408c-9e26-ffe6436215f1","Strategies for Orchestrating and Managing Supply Chains in Public Service Networks","Van Veenstra, A.F.; Janssen, M.F.W.H.A.; Klievink, B.","","2009","Joining-up is high on the e-government agenda as this is expected to improve service delivery to citizens and businesses. It requires public and private organizations to cooperate with each other within networks that are formed around public services that cross the boundaries of organizations. Cross-organizational processes in such a network are called supply chains, aimed at delivering integrated services. The performance of each individual organization within the network influences aspects such as lead-time and quality of services delivered. In order to effectively integrate the efforts of the various organizations involved, a strategy needs to be in place to orchestrate and manage a service delivery chain. Various types of strategies can be employed. Yet little knowledge is available about which strategies are effective under which circumstances. In this paper we identify four different strategies for managing and orchestrating cross-organizational service chains. These supply chain management (SCM) strategies are based on literature research and case study analysis. The four strategies are identified based on two dimensions: the level of control (i.e. governance structure) and the architectural approach for systems integration. These four strategies are: merger, orchestra, relay race, and broadcasting. For three of the four strategies, illustrative cases have been found. The strategy selection depends on factors such as the institutional environment, political ambitions and organizational readiness. Furthermore, each strategy has its own merits and demerits. We recommend investigating the relationship between situational characteristics and SCM strategies in further research.","e-government; joined-up government; Supply Chain Management; inter-organizational collaboration; governance; integration strategy","en","journal article","Academic Publishing Limited","","","","","","","","Technology, Policy and Management","Infrastructure Systems & Services","","","",""
"uuid:6741902f-fc75-4bc2-91d5-5d204218c6d6","http://resolver.tudelft.nl/uuid:6741902f-fc75-4bc2-91d5-5d204218c6d6","A framework for the study of grid inter-operation mechanisms","Iosup, A.","Sips, H.J. (promotor); Epema, D.H.J. (promotor)","2009","The study of the history of computing infrastructures reveals an integration trend. For example, the explosive growth of the Internet in the 1990s was the result of an integration process started in the 1960s with the emerging networks of computers. By using the Internet, millions of users were capable of accessing information anytime and anywhere, much like other daily utilities such as water, electricity, and telephone. However, an important category of users remained under-served: the users with large computational and storage requirements, e.g., the scientists, the companies that focus on data analysis, and the governmental departments that manage the interaction between the state and the population (such as census, tax, and public health). Thus, in the mid-1990s, the vision of the (Computing) Grid as a universal computing utility was formulated. The main benefits promised by the Grid are similar to those of other integration efforts: extended and optimized service of the integrated network, and significant reductions of maintenance and operation costs through sharing and better scheduling. While the universal Grid has yet to be developed, large-scale distributed computing infrastructures that provide their users with seamless and secure access to computing resources, individually called Grid parts or simply grids, have been built throughout the world---in different countries, for different sciences, and both for production work and for computer-science research. At the same time, the main technological alternatives to grids, that is, supercomputers and large clusters, have evolved into much larger, scalable, and reliable systems. Thus, the integration of existing grids into larger infrastructures and finally into The Grid is key in keeping the grid vision attractive for its potential users. The integration of grids raises a double challenge, one related with the efficient scaling of a distributed computing system, the second associated with the operation of a system across different ownership and administrative domains. Thus, many of the traditional approaches for inter-operating computer systems, such as those based on completely centralized or purely decentralized system architectures, are eliminated from the start. To mark the distinction between the typical problem of integrating smaller components into a larger system and the double challenge of grid integration, we call the latter the problem of grid inter-operation. In this thesis we approach the problem of grid inter-operation with two main objectives: to design a comprehensive framework for the study of grid inter-operation mechanisms, and to provide an initial but good solution for this problem. We design a framework for the study of grid inter-operation that includes a toolbox for grid inter-operation research and a method for the study of grid inter-operation mechanisms. In the research toolbox we include the Grid Workloads Archive (GWA), a comprehensive model for grid resources and workloads, the GrenchMark performance evaluation framework, and the Delft Grid Simulation (DGSim) framework for repeated and realistic simulations of multi-cluster and multi-grid environments. The GWA and our comprehensive model show that grid computing is mostly used in practice for single-processor jobs and not for parallel computing, which raises previously ignored challenges related to the volume of jobs to be managed. We also devise in this thesis a method for studying grid inter-operation mechanisms. We answer using our framework important questions regarding existing grid operation mechanisms, and in particular show that these mechanisms are too limited to cope with real and realistic conditions. We further demonstrate the usefulness of our framework by designing Delegated MatchMaking, a novel mechanism for inter-operating grids. This mechanism is used to operate an architecture that is a hybrid between hierarchical and purely decentralized architectures. The Delegated Matchmaking mechanism attempts to use the local resources of a grid as much as possible and also transparently extends the local environment with resources obtained (delegated) from other sites when resources are not available locally. Our approach is compared with five alternatives through trace-based simulations, and is found to deliver the best performance, especially when the system is heavily loaded. While many other mechanisms can be designed in the future, our experiments prove that the Delegated MatchMaking approach already is a good solution for the problem of grid inter-operation. Our experiments also demonstrate that having grids inter-operate leads to better performance than having the same grids operate independently.","grid inter-operation; grid computing; distributed systems; trace-based simulation; research toolbox; mechanism design; performance evaluation; performance analysis; supercomputing; cloud computing; grid workloads archive; dgsim; grenchmark","en","doctoral thesis","","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:65e09cf9-573f-4839-a671-8edcba31eda4","http://resolver.tudelft.nl/uuid:65e09cf9-573f-4839-a671-8edcba31eda4","All for one: Factors for alignment of inter-dependent business processes at KLM and Schiphol","Perié, R.P.","Santema, S.C. (promotor)","2008","As airline and hub competition becomes fiercer, airline-airport co-operation becomes a necessary option for both main carrier airlines and hub airports to face this competition together. The inter-dependency between airlines and airports in producing air-transport services is tight, i.e. their destinies are inter-twined. Their existence as viable economic entities depends upon market performance of each other. This leads to the assumption that the relation of airlines' airports serves as an example case for dyadic alignment. Although research has been carried out regarding many forms of co-operation, little is known about specifically alignment at the business process level. By alignment of their inter-dependent dyadic business processes competitive advantage can be obtained; both KLM and AAS have acknowledged this. The aim of this research is to determine Factors for Alignment for specific inter-dependent business processes at KLM and AAS. For research purposes the research question is formulated as follows: Which are the factors for alignment of dyadic business processes at KLM and AAS? Answers to this research question are to increase the understanding of the effect of different factors upon alignment. This research has a theoretical as well as a practical value. It develops a theoretical Delft Factors for Alignment (DFA) model. This enables subsequent development of analysis tools that quantitatively and qualitatively measure the performance of Factors for Alignment. For practical purposes, it identifies issues and maps differences and similarities present between KLM and AAS within their specific dyadic business processes. These dyadic processes are Environmental Capacity, Network Planning, Infrastructure Planning and Aircraft Stand Allocation. This research is based upon the assumption that alignment of the dyadic business processes of KLM and AAS is achieved by addressing the issues affecting alignment regarding various subjects within each business process, as indicated by employees of these firms. By making use of interviews and questionnaires within both firms it is found that the issues present within four dyadic business processes of these firms, at three different levels of decision making, can be modeled by the developed DFA model. The model identifies the most potential of Factors for Alignment of their dyadic business processes. It is proven that the DFA model is a diagnostic tool in finding the Factors for Alignment of dyadic business processes of KLM and AAS by creating a structured ordering of the issues by interviews and questionnaires. The research question, as formulated above, is answered by primary and secondary Factors for Alignment per business process. This also implies that the DFA model is effective for analysis of dyadic business processes. The research methodology has proven to be viable. This would encourage application for research of other dyadic business processes at KLM and AAS, which could also strengthen their competitive advantage.","factors; alignment; business processes; dyads; inter-dependency; airline-airport relationship","en","doctoral thesis","","","","","","","","","Aerospace Engineering","","","","",""
"uuid:9adfd1de-cd2c-4d26-9efc-3a0e59405640","http://resolver.tudelft.nl/uuid:9adfd1de-cd2c-4d26-9efc-3a0e59405640","A Novel Receiver Architecture for Single-Carrier Transmission over Time-Varying Channels","Tang, Z.; Leus, G.","","2008","In this paper, we present a single-carrier transceiver for rapidly time-varying channels, where the equalization step is implemented in the frequency domain. When the channel abides with both fast fading and severe inter-block interference, our equalizer relies on a band approximation of the frequencydomain channel matrix to maintain low complexity. We will show that the band approximation error can be associated in the time domain to a critically-sampled complex exponential basis expansion modeling error. Based on this property, we propose a novel receiver architecture that extends the original data model by inserting zeros at the receiver. The resulting effective channel can be characterized by an oversampled complex exponential basis expansion model, which has a considerably reduced modeling error compared to the critically-sampled one. In other words, the band assumption that is essential to the equalizer will be made more accurate and thus the equalization performance can be improved.","single-carrier; basis expansion model; timevarying channels; inter-block interference","en","journal article","IEEE","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Microelectronics & Computer Engineering","","","",""
"uuid:f31c94d1-de3e-4127-8534-e6535bb97f59","http://resolver.tudelft.nl/uuid:f31c94d1-de3e-4127-8534-e6535bb97f59","Adaptive corporate environments: Creating real-time interactive spatial systems for corporate offices incorporating computation techniques","Biloria, N.","Van Duin, L. (promotor); Oosterhuis, K. (promotor)","2007","","interactive architecture; real time interaction; spatial augmentation; inter-disciplinary; interaction design; software development; interface design; multiple usability of space; scripting; ambience regulation; pneumatics; control systems","en","doctoral thesis","","","","","","","","","Architecture","","","","",""
"uuid:c5b55436-9566-40da-b74d-6a41bc7dc3a5","http://resolver.tudelft.nl/uuid:c5b55436-9566-40da-b74d-6a41bc7dc3a5","Implementing inter-organisational service systems: An approach for emerging networks in volatile contexts","Mulira, N.K.","Sol, H.G. (promotor)","2007","Public organizations in the developing world are undergoing a gradual but irreversible change, due to innovations in information and communications technologies. The emergence of business networks, among such organizations, indicates an increasing interdependence and a search for solutions to regain waning strategic relevance and competitive advantage. In this research we note that, the emerging public organizational networks in the developing world, work in unpredictable environments with resource scarcity. The environment is volatile and a potential obstacle to improving implementation practices for emerging networks. To find solutions that can improve the reliability and efficiency of the implementation practices, we focus on the implementation challenges that emerging inter-organizational networks currently face in implementing service systems for business collaboration. We define solutions that use repeatable processes for inter-organizational business IS implementation, avoiding the need to change the focus of the core business processes.","inter-organisational networks; volatility; implementation approach; information service systems","en","doctoral thesis","","","","","","","","","Technology, Policy and Management","","","","",""
"uuid:687098f1-aedb-4a2a-87b5-92dab3ed42f1","http://resolver.tudelft.nl/uuid:687098f1-aedb-4a2a-87b5-92dab3ed42f1","Space and crime in Dutch built environments: Macro and micro scale spatial conditions for residential burglaries and thefts from cars","Lopez, M.J.J.; Van Nes, A.","","2007","At this moment, more knowledge is available on the physical characteristics of the built environment and their relationship to criminal opportunity rather than the spatial characteristics of potential targets and the public and private space between them. To improve this situation, a research project was started in the Dutch cities Gouda and Alkmaar that aimed to address several spatial characteristics of the built environment, to develop a method to quantify these characteristics and to relate them to the geographic distribution of residential burglaries and thefts from carsi. The predominant task consisted in identifying the spatial conditions on various scale levels - in terms of the street net’s configuration - and the relationship between private and public space favouring burglaries and theft from cars. Furthermore, statistical analysis was used to study the relationship between crime risk and spatial configuration on various scale levels.","space and crime; risk band analyses; angular analyses; inter-visibility; topological depth","en","conference paper","","","","","","","","","Architecture and The Built Environment","Urbanism","","","",""
"uuid:93cee4fe-8c5b-4c97-a552-916ee4ceb97f","http://resolver.tudelft.nl/uuid:93cee4fe-8c5b-4c97-a552-916ee4ceb97f","In search for an appropriate granularity to model routing policies","Mühlbauer, W.; Uhlig, S.; Fu, B.; Meulle, M.; Maennel, O.","","2007","","BGP; inter-domain routing; routing policies","en","conference paper","ACM","","","","","","","","Electrical Engineering, Mathematics and Computer Science","","","","",""
"uuid:f387211a-6018-49cf-ab19-8cdfa6948346","http://resolver.tudelft.nl/uuid:f387211a-6018-49cf-ab19-8cdfa6948346","VERVOERMIDDELENGEBRUIK IN HET WOON-WERKVERKEER VAN INWONERS UIT KLEINE KERNEN.; TRAVEL PATTERNS AND MODE USE OF COMMUTERS FROM SMALL TOWNS.","Gommers, W.; Bovy, P.H.L.","","1988","","Conference 8525 transport 1155 inter urban 0388 low density area 0376 journey to work 0621 transport mode 1145 private transport 1136 public transport 1165 congestion traffic 0632 urban area 0313 journey 0698 population 0335 netherlands 8078 Traffic and t; flow","nl","conference paper","COLLOQUIUM VERVOERSPLANOLOGISCH SPEURWERK, GEERDINKHOF 237, AMSTERDAM, 1103 PZ, NETHERLANDS","","","","","","","","","","","","",""
"uuid:7840e62c-948c-4c50-b2bb-7de46ad9f020","http://resolver.tudelft.nl/uuid:7840e62c-948c-4c50-b2bb-7de46ad9f020","Kinematics and Directionality of Waves in the Surf Zone","Van Heteren, J.; Stive, M.J.F.","Rijkswaterstaat","1985","Realistic modelling of the internal kinematics of wind waves breaking on a beach is of great practical importance, e.g. for the modelling of coastal processes and for the design of coastal structures. A fundarnental aspect in this modelling concerns. the relation between the surface elevation and the internal kinematics. In this respect it appears that in water of interrnediate relative depth the linear Gaussian model of the wave motion performs satisfactorily (see Battjes and Van Heteren, 1983, 1984). Although the linearity assumption is expected to be violated near and in the surf zone, it is practically useful to check the quantitative performance of the linear Gaussian model in this case. An important part of the present study is devoted to the applicability of this theory, making use of field measurements which were collected in the spring of 1981 on the beach near Egmond. The quantitative performance of linear theory in predicting the wave kinematics from the surface elevation is investigated on the basis of spectral transfer functions between surface elevation and velocity and of measured and theoretical r.m.s. fluctuation of the velocity. As far as the spectral transfer functions are concerned the squared coherence, the gain and the phase were investigated between surf ace elevation and both horizontal and vertical velocity. Relevant earlier studies on the performance of linear theory in the surf zone are those of Thorn ton et al. (1976), of Mitsuguchi et al. (1980) and of Guza and Thornton (1980). The general findings are that linear theory generally overestimates wave induced horizontal veloci ties by 10% to 30%. Mitsuguchi et al. merely state their conclusion without analyzing apparent trends in their data with e.g. increasing frequency. They only consider alirnited set of horizontal velocity data. Guza and Thornton obtain their overall conclusion merely on the basis of the r.m.s. fluctuation of the horizontal velocity as measured and as predicted with the linear theory from the surface elevation. The present study confirrns the conclusions of the above investigations by and large, but extends the analysis both in width by including the vertical velocities and in depth by investigating the role of turbulent kinetic energy generated by breaking. Also special attention is given to the phase relationship between the vertical velocity and the horizontal velocity, and between the vertical velocity and the surface elevation.","interal kinemates; wind waves; wave breaking; surf zone; wave modelling; turbulent kinetic energy","en","report","Rijkswaterstaat, RIKZ","","","","","","","","","","","","",""