"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:ee06f0fb-aeb1-4fff-8905-1da3df4e5133","http://resolver.tudelft.nl/uuid:ee06f0fb-aeb1-4fff-8905-1da3df4e5133","Improving the data quality checking process during the design phase: Development of a design-integrated data checking and reporting tool","Alonso Candau, Jaime (TU Delft Civil Engineering & Geosciences)","Wamelink, J.W.F. (mentor); van Nederveen, G.A. (mentor); Wang, T. (graduation committee); Arts, D. (graduation committee); Delft University of Technology (degree granting institution)","2023","One of the crucial aspects of BIM is the data rich environment connecting project information from different sub-sectors. (Mesároš et al., 2020). Therefore, developing models with consistent and trustworthy building data has gained significant importance in the industry. In contrast, incorrect or incomplete building data in a model could result in chained mistakes across disciplines, rework, or inadequate models for other stages of the building lifecycle.
Most of the improvements in BIM data in organisations take place in data quality reviews by BIM specialists. The lack of integration and complexity of existing data checking tools raised the expertise leading to assessment tools used mostly by BIM specialists. After a specialist reviews a project, corrections are communicated to the designers to solve the data issues in their models. This process is repeated until the desired quality is reached by the design team. Furthermore, missing, or wrong basic data structure can often lead to incomplete or inaccurate data checking processes.
The higher goal of this research is to produce perceivable benefits in the organisational data checking process. This is approached by facilitating the implementation of BIM standards and increasing the compliance of objects during design periods before entering the organisational review. Previous research showed that professionals would prefer to use simple dedicated quality checkers that can minimise manual tasks precisely and reliably instead of advanced software solutions. Thus, the goal is not to replace current workflows and practices, but instead to enhance basic data structures in models before entering the data reviews, by developing and implementing a new design-integrated checking and reporting tool.
The new checking process was verified and validated with specialists and modelers in three ongoing projects. This research showed that the developed design-integrated tool can produce the perceivable benefits in the organisational data checking process explained below:
•Enhancements in data quality before and after regular organisational checking reviews.
•Decrease in the duration and iterations in the organisational reviews.
•Increase of effectiveness and efficiency in detection and correction of data quality issues.
•Decrease of personnel frustration in the organisational process.
Thus, the research fulfilled the main objective to produce perceivable benefits in the organisational data checking process by developing and implementing a dedicated solution that engages designers in the process. The role-specific approach was essential to achieve a solution that meets the specific needs and system requirements of the target group, the designers. The purpose was to add a new prechecking layer to support and enhance existing data quality practices and processes. The result was a steering instrument for modelers working on the detailed design phase to involve them in identifying and correcting data quality issues.
Although the perceived benefits may vary in different contexts and organisations, the new data checking and reporting solution would raise awareness and promote designers’ engagement in the organisational data checking process, who are in a dominant position to identify and correct data quality issues.","BIM; Business Process Improvement; Data Quality; BIM Standards","en","master thesis","","","","","","","","","","","","Civil Engineering | Construction Management and Engineering","",""
"uuid:27823a21-e33a-494d-b2df-46aea9e7b6bd","http://resolver.tudelft.nl/uuid:27823a21-e33a-494d-b2df-46aea9e7b6bd","An innovative way to transport and spool offshore power cables using SPMTs: Global design improvement of a containerized carousel system","Slingerland, Bas (TU Delft Mechanical, Maritime and Materials Engineering)","van den Bos, W. (mentor); Schott, D.L. (graduation committee); Frikkee, E.A. (graduation committee); Harms, I. (mentor); Delft University of Technology (degree granting institution)","2023","Mammoet is developing a new type of system for the transportation of offshore power cables. With this system the cables can be spooled, stored, and transported both on land and on heavy transport vessels in a more efficient way. There are a few uncertainties for the system, mainly about the loads on the carousel and the behavior of the cable stack. These uncertainties resulted in some assumptions that have been used for the proposed design. Furthermore, there are a few challenges for the system that need to be addressed to compete with the current offshore power cable transportation methods. The main challenges include the structural strength and stability in combination with the self-weight, the used cylinder stroke of the hydraulic SPMT cylinders and other issues with the SPMTs. In this study these uncertainties and the challenges for the current design of the system are investigated, which resulted in more insight in the uncertainties and a new concept with improved performance against the challenges.","Carousel; Heavy transport; Offshore power cables; Offshore power cable transport; Design improvement","en","master thesis","","","","","","","","","","","","Mechanical Engineering | Multi-Machine Engineering","",""
"uuid:92dafb38-b093-4fda-b8ac-21f24641a977","http://resolver.tudelft.nl/uuid:92dafb38-b093-4fda-b8ac-21f24641a977","Investigating the rheological properties and compatibility behaviours of RET/PE and WR/CR/ SBS compound-modified bitumen","Ren, S. (TU Delft Pavement Engineering); Liu, X. (TU Delft Pavement Engineering); Jing, R. (TU Delft Pavement Engineering); Gao, Y. (Liverpool John Moores University); Lin, P. (TU Delft Pavement Engineering); Erkens, S. (TU Delft Pavement Engineering)","","2023","Two types of elastomer/plastic compound-modified bitumen were developed by means of incorporating the reactive elastomeric terpolymer (RET) into the plastic (high-density polyethylene HDPE or recycled polyethylene RPE) modified bitumen and adding the wax residue (WR) into the bitumen/elastomer (crumb rubber CR or styrene–butadiene–styrene SBS) blends. The rheological properties, morphology microstructure and storage stability of these novel elastomer/plastic compound-modified binders were characterised. The results revealed that RET elastomer positively improved the high-temperature modulus, temperature insensitivity, rut resistant, elastic recovery and shear-resistance of HDPE- and RPE-modified bitumen. However, excessive RET dosage adversely influenced the cracking resistance of plastic-modified bitumen, and its optimum dosage was recommended as 1 wt%. Moreover, RET elastomer significantly strengthened the storage stability of HDPE and RPE-modified binders. The elasticity improvement effect of RET was attributed to the generated polymer network. On the other hand, adding WR limitedly deteriorated the rutting resistance and weakened the elastic recovery performance of elastomer (CR and SBS) modified bitumen. To ensure the low-temperature performance, the optimum level of WR was 2 wt%. Furthermore, the addition of WR promoted the compatibility and dispersion of CR and SBS modifiers in bitumen.","Waste utilisation; compound modified bitumen; elastic/plastic performance improvement; rheological characterisation; rheological characterisation;","en","journal article","","","","","","","","","","","Pavement Engineering","","",""
"uuid:6ef9c5e9-60f8-4916-9aae-dadb38d9b560","http://resolver.tudelft.nl/uuid:6ef9c5e9-60f8-4916-9aae-dadb38d9b560","A small sample data-driven method: User needs elicitation from online reviews in new product iteration","Cong, Yangfan (Northwestern Polytechnical University); Yu, Suihuai (Northwestern Polytechnical University); Chu, Jianjie (Northwestern Polytechnical University); Su, Zhaojing (Northwestern Polytechnical University); Huang, Y. (TU Delft Design Conceptualization and Communication; Northwestern Polytechnical University); Li, Feilong (Northwestern Polytechnical University)","","2023","Eliciting user needs from mass online reviews is playing a significant role in the product iteration process. Efficient user needs elicitation does achieve considerable benefits for maintaining higher competitiveness and a speedier lifecycle. However, there is inevitably an online review scarcity about new products due to the short time on the market and low buyer recognition compared with commonly used products. This paper proposes a small sample data-driven method for user needs elicitation from online reviews in new product iteration. In the first stage, a scraped initial online review dataset is pre-processed roughly to improve the data quality. And then, reviews are classified into multiple categories according to different topics using ERNIE. In the second stage, each topic-based dataset is reprocessed in detail. Thereafter, the key user needs set is determined and facilitated by extracting key product information phrases from every single dataset using improved SIFRank. Moreover, the case study of a smart cat feeder is carried out to demonstrate the feasibility and potential of the ERNIE-ISIFRank methodology. Finally, comparative experiments are conducted to verify the advantages of the proposed method which is primarily based on the pre-trained language model to enhance the deep understanding of the semantics of online reviews. The experimental results confirm that the proposed method can assist in identifying key user needs with high efficiency.","ERNIE; Improved SIFRank; New product iteration; Small sample data-driven; User needs elicitation","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2023-09-30","","","Design Conceptualization and Communication","","",""
"uuid:aca57973-db89-4132-abcd-ca26bfa422ef","http://resolver.tudelft.nl/uuid:aca57973-db89-4132-abcd-ca26bfa422ef","A Self-Bias-Flip with Charge Recycle Interface Circuit with No External Energy Reservoir for Piezoelectric Energy Harvesting Array","Li, Zhen (Fudan University); Chen, Zhiyuan (Fudan University); Wang, Jing (Fudan University); Wang, Jiawei (Fudan University); Jiang, Junmin (Southern University of Science and Technology); Du, S. (TU Delft Electronic Instrumentation); Cheng, Xu (Fudan University); Zeng, Xiaoyang (Fudan University); Han, Jun (Fudan University)","","2023","This article presents a piezoelectric energy harvesting (PEH) interface circuit using a new self-bias-flip with the charge recycle (SBFR) technique without employing any additional energy reservoir. Traditional designs, including synchronous-switch harvesting on inductor (SSHI), synchronous-switch harvesting on capacitor (SSHC), synchronous electric charge extraction (SECE), etc., require additional capacitors or inductors to reverse the voltage on the PEH at the zero-crossing point. This design innovatively uses the inherent capacitors of the piezoelectric harvesters as the flipping capacitors. In order to improve the extract efficiency of the interface, the zero-crossing state is split into a charge recycle stage and a voltage-flip stage. For a piezoelectric array with 2^n PEHs, a configuration with (n-1) phases in the charge recycle stage is adopted to reduce the loss caused by direct charge neutralization. The charge redistribution loss is reduced by employing (2n+1) phases in the voltage-flip stage. The proposed principle has been implemented with discrete components and is verified by three different prototypes. The measurement results show that a flipping efficiency of 67% is achieved by utilizing SBFR with four PEHs. And the proposed interface can provide up to 5.2x improvement when compared with the full-bridge rectifier (FBR).","Energy harvesting; maximum output power improving rate (MOPIR); multiple input; piezoelectric energy harvester (PEH); self-bias-flip; synchronous-switch harvesting on inductor (SSHI)","en","journal article","","","","","","Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.","","2024-01-15","","","Electronic Instrumentation","","",""
"uuid:c6b245d5-e79b-45f7-b6a4-3f5bddef0af8","http://resolver.tudelft.nl/uuid:c6b245d5-e79b-45f7-b6a4-3f5bddef0af8","A comparison of earthwork designs for railway transition zones","Chumyen, P. (University of Leeds); Connolly, D. P. (University of Leeds); Woodward, P. K. (University of Leeds); Markine, V.L. (TU Delft Railway Engineering)","","2023","Railway track transitions are zones where there is an abrupt change in the track-ground structure. They are often the location of rapid track deterioration, which means more frequent track maintenance is needed compared to plain line tracks. With the aim of reducing maintenance, modern transition zone designs use tapered stiffness earthwork profiles to minimise train-track dynamics. However, there has been limited comparison regarding the effect of different tapered profiles on dynamic behaviour. Therefore, this paper's novelty is the investigation of the performance of different earthwork designs in smoothing stiffness transition's considering different types of improvement and also train speed. To do so, first a 3D finite element track model is developed, with support conditions transitioning from an earth embankment onto a concrete bridge. A dynamic moving train load is simulated using a rigid multi-body approach capable of accounting for train-track interaction. The model is used to study the effect of four earthwork solutions with differing stiffness tapers. For each scenario, two different track structure types (ballast and concrete slab) are considered, along with different magnitudes of ground improvement. Lastly, the effects of train speed are explored. It is found tapered earthwork solutions for ballasted tracks show greater dynamic improvement compared to slabs due to their reduced bending stiffness. Further, the more complex improvement geometries such as double trapezoid shapes offer some additional improvement at locations within 3 m of the bridge. However, when considering such tapered stiffness-based earthwork solutions, additional factors such as constructability must also be considered.","Embankment-Bridge transition zones; Ground improvement; Railroad dynamics; Railway Transition Earthworks; Wedge-shaped soil reinforcement","en","journal article","","","","","","","","","","","Railway Engineering","","",""
"uuid:caf7a443-1007-4fb4-8d47-aa1460e7f7b3","http://resolver.tudelft.nl/uuid:caf7a443-1007-4fb4-8d47-aa1460e7f7b3","Also for k-means: more data does not imply better performance","Loog, M. (TU Delft Pattern Recognition and Bioinformatics; Radboud Universiteit Nijmegen); Krijthe, J.H. (TU Delft Pattern Recognition and Bioinformatics; Radboud Universiteit Nijmegen); Bicego, Manuele (University of Verona)","","2023","Arguably, a desirable feature of a learner is that its performance gets better with an increasing amount of training data, at least in expectation. This issue has received renewed attention in recent years and some curious and surprising findings have been reported on. In essence, these results show that more data does actually not necessarily lead to improved performance—worse even, performance can deteriorate. Clustering, however, has not been subjected to such kind of study up to now. This paper shows that k-means clustering, a ubiquitous technique in machine learning and data mining, suffers from the same lack of so-called monotonicity and can display deterioration in expected performance with increasing training set sizes. Our main, theoretical contributions prove that 1-means clustering is monotonic, while 2-means is not even weakly monotonic, i.e., the occurrence of nonmonotonic behavior persists indefinitely, beyond any training sample size. For larger k, the question remains open.","k-Means algorithm; k-Means clustering; Learning curve; Monotonicity; Performance improvement; Smartness","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:77736000-30c1-4c51-be17-bc34bb2037ab","http://resolver.tudelft.nl/uuid:77736000-30c1-4c51-be17-bc34bb2037ab","Bio2Cementation: A novel treatment coupling clay aggregation and bio-cementation in sand-bentonite porous media","Wennubst Pedrini, Rocco (TU Delft Civil Engineering & Geosciences)","Dieudonné, A.A.M. (mentor); Gebert, J. (graduation committee); Jonkers, H.M. (graduation committee); Delft University of Technology (degree granting institution)","2022","The geo-technical quest to couple technical, environmental, and economic innovation, has increased recent attention towards bio-inspired soil strengthening techniques. This thesis presents a proof-of-concept for a coupled clay inhibition and bio-cementation treatment tested in sand-bentonite, referred to as Bio2Cementation. Fine particles are first aggregated using a nitrogen based compound. By binding the electrical double layer of clay minerals, the aggregates become chemically and physically stable. Thereafter, bio-cementation treatments hydrolyze urea to precipitate calcium carbonate crystals within the pore space. The crystals bind the mineral particles, increasing the strength and stiffness of the soil.
State of the art considerations regarding enzyme induced calcite precipitation and guanidinium hydrochloride research are used as the theoretical foundation for the treatment’s design. A diverse sand-bentonite matrix is tested, comprised of 10% and 30% bentonite, to evaluate the applicability limits of the technique. The implementation is tested in flow-cells, whereby soils are injected with Bio2Cementation treatments. Experiments show the dominant role of guanidine for stabilizing clay particles – the matrix aggregates, hydraulic conductivity improves by two orders of magnitude, surface charge interactions are minimized, and swelling is halted irreversibly. Hydraulic conductivity calcultations, unconfined compressive strength tests, image analysis of Micro-CT scans, and scanning electron microscope imaging evidence to notably improved bio-cementation following guanidine injections. Consistently, the optimized enzyme induced calcite precipitation was found to crystallize vigorously in 10% bentonite samples, but less successfully in optimally compacted 30% bentonite soils. The concept of Bio2Cementation is proven to work within certain limitations.
Future research should explore the role of different clay minerals such as kaolinite, in view of better defining the treatment’s engineering applicability in-situ. Additional strength testing, soil-structure interaction analyses and environmental impact studies are also recommended
s, that was interrupted at 25 and 50% of transformation, followed by a second stage treatment at a lower temperature to complete the bainitic transformation. One- and two-step treatments were performed in a high-resolution dilatometer, and the critical transformation temperatures and phase transformation kinetics were determined from the longitudinal changes recorded during these tests. It was shown that blocky-type austenite was almost completely eliminated after the two-step treatments, which in turn positively reduced the amount of fresh martensite from ∼6 to «1%. It was possible to keep the volume fraction of retained austenite above 10%, while reducing both the thickness of the bainitic plates and the film-like retained austenite by 20% and more than 40%, respectively. These microstructural characteristics made it possible to increase the hardness of the alloy by approximately 50 HV and yield strength by 180 MPa.","Bainitic transformation; Double austempering; Medium-Mn steels; Microstructure tailoring; Plate thickness reduction; Retained austenite morphology; Strength improvement","en","journal article","","","","","","","","","","","Team Kevin Rossi","","",""
"uuid:654d7a97-cb70-4a5f-be20-5112816b8bfa","http://resolver.tudelft.nl/uuid:654d7a97-cb70-4a5f-be20-5112816b8bfa","Improved oil recovery techniques and their role in energy efficiency and reducing CO2 footprint of oil production","Farajzadeh, R. (TU Delft Reservoir Engineering; Shell Global Solutions International B.V.); Glasbergen, G. (Shell Global Solutions International B.V.); Karpan, V. (Shell Development Oman, Muscat); Mjeni, R. (Petroleum Development Oman); Boersma, D. M. (Shell Global Solutions International B.V.); Eftekhari, A. A. (Technical University of Denmark); Casquera Garcia, A. (Student TU Delft); Bruining, J. (TU Delft Reservoir Engineering)","","2022","Production of mature oil fields emits significant amount of CO2 related to circulation and handling of large volumes of gas and water. This can be reduced either by (1) using a low-carbon energy source and/or (2) reducing the volumes of the non-hydrocarbon produced/injected fluids. This paper describes how improved oil recovery techniques can be designed to reduce CO2 intensity (kgCO2/bbl oil) of oil production by efficient use of the injectants. It is shown that CO2 emissions associated with injection of chemicals is strongly influenced by water cut at the start of the project, extent of the water cut reduction, and chemical utilization factor defined as the volume of produced oil per mass or volume of the injectant. As an example, for the oil field considered in this study, 3–8% reduction in water cut can result in 50–80% reduction in its CO2 intensity. In addition to the incremental oil production with lower CO2 intensity, the earlier implementation of enhanced oil recovery methods can extend the lifetime of the mature fields if carbon emission cut-offs are applied. In case of CO2 enhanced oil recovery (EOR), the large storage potential for CO2 can significantly reduce the overall CO2 emissions of oil, albeit at a large energetic cost. For CO2 EOR using CO2 captured from gas power plants, improving the utilization factor from 2 bbl/tCO2 to 4 bbl/tCO2 can reduce the CO2 intensity of the produced oil from 120 kgCO2/bbl to 80 kgCO2/bbl (33% reduction).","Climate change; CO intensity; Enhanced oil recovery; Exergy analysis; Improved oil recovery","en","journal article","","","","","","","","","","","Reservoir Engineering","","",""
"uuid:81625d08-2b0b-4b2e-8d59-f707fa16430a","http://resolver.tudelft.nl/uuid:81625d08-2b0b-4b2e-8d59-f707fa16430a","Marginal and Dependence Uncertainty: Bounds, Optimal Transport, And Sharpness","Bartl, Daniel (University of Vienna); Kupper, Michael (Universität Konstanz); Lux, Thibaut (Helvetia Insurance Group); Papapantoleon, A. (TU Delft Applied Probability)","","2022","Motivated by applications in model-free finance and quantitative risk management, we consider Frechet classes of multivariate distribution functions where additional information on the joint distribution is assumed, while uncertainty in the marginals is also possible. We derive optimal transport duality results for these Frechet classes that extend previous results in the related literature. These proofs are based on representation results for convex increasing functionals and the explicit computation of the conjugates. We show that the dual transport problem admits an explicit solution for the function f = 1B, where B is a rectangular subset of Rd, and provide an intuitive geometric interpretation of this result. The improved Frechet-Hoeffding bounds provide ad hoc bounds for these Frechet classes. We show that the improved Frechet-Hoeffding bounds are pointwise sharp for these classes in the presence of uncertainty in the marginals, while a counterexample yields that they are not pointwise sharp in the absence of uncertainty in the marginals, even in dimension 2. The latter result sheds new light on the improved Frechet-Hoeffding bounds, since Tankov [J. Appl. Probab., 48 (2011), pp. 389-403] has showed that, under certain conditions, these bounds are sharp in dimension 2.","dependence uncertainty; Frechet classes; improved Frechet-Hoeffding bounds; marginal uncertainty; optimal transport duality; relaxed duality; sharpness of bounds","en","journal article","","","","","","","","","","","Applied Probability","","",""
"uuid:d9cc6841-58ff-464c-a31d-8955e977ec0d","http://resolver.tudelft.nl/uuid:d9cc6841-58ff-464c-a31d-8955e977ec0d","Between Tradition and Modernity: Western urban planning and street improvement projects in Hankou (1889-1937)","Ren, X. (Southeast University); Li, Baihao (Southeast University); Hein, C.M. (TU Delft History, Form & Aesthetics)","","2022","This article examines street improvement projects in Hankou's case for unearthing the contribution of Chinese political elites and planers in exchanging planning concepts and technologies from the West to China. Aiming to realize the Modern Metropolis, which Sun Yat-sen proposed in the fundamentals of national reconstruction, Chinese political elites and planers selected, borrowed, and imported western planning ideas to transform traditional Hankou city by implementing street improvement projects. Using the case of street improvement of Hankou during the Late Qing period(1889-1911), Early Republic China period(1911-1926), and Municipal Government period(1926-1937) as case studies, this article examines street improvement projects which authorities developed for Hankou in three different periods. By analyzing planning concepts, street plans(both realized and planned), and management regulations of these projects, the paper argues that improvement projects aimed to develop economic and industrial and improve public hygiene. Furthermore, the Chinese political and planning elites imported European and American design principles and practiced them in the Hankou local context for their own needs. In conclusion, the built environment showed hybridization features after implementing continuous planning schemes.","Hankou; urban transformation; planning history; street improvement; modernity","en","conference paper","Delft University of Technology","","","","","","","","","","History, Form & Aesthetics","","",""
"uuid:cc799877-64f3-4368-ac61-7fb7956e31fb","http://resolver.tudelft.nl/uuid:cc799877-64f3-4368-ac61-7fb7956e31fb","Polarimetric calibration of spaceborne and airborne multifrequency SAR data for scattering-based characterization of manmade and natural features","Kumar, Shashi (Indian Institute of Remote Sensing); Babu, Arun (Indian Institute of Remote Sensing; Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)); Agrawal, Shefali (Indian Institute of Remote Sensing); Asopa, U. (TU Delft Mathematical Geodesy and Positioning; Indian Institute of Remote Sensing); Shukla, S. (TU Delft Physical and Space Geodesy; Indian Institute of Remote Sensing; International Institute for Geo-Information Science and Earth Observation (ITC)); Maiti, Abhisek (Indian Institute of Remote Sensing; International Institute for Geo-Information Science and Earth Observation (ITC))","","2022","The Polarimetric Synthetic Aperture Radar (PolSAR) systems use electromagnetic radiations of different polarizations in the microwave frequency to collect the scattering information from targets on the Earth. Nevertheless, as with any other electronic device, the PolSAR systems are also not ideal and subjected to distortions. The most important of these distortions are the polarimetric distortions caused due to the channel imbalance, phase bias, and crosstalk between the different polarization channels. For the spaceborne PolSAR systems, the Earth's ionosphere also contributes to an additional polarimetric distortion known as the Faraday rotation. An effort was made in this study to perform the polarimetric calibration of the Quad-pol and Compact-pol PolSAR datasets acquired using different airborne and spaceborne PolSAR systems to estimate and minimize these polarimetric distortions. The investigation was also done to analyze the impact of these polarimetric distortions on the scattering mechanisms from ground targets and on its dependency on the radar wavelength. The study was done using the UAVSAR L-band Quad-pol dataset, RADARSAT-2 Quad-pol dataset, ALOS-2 PALSAR-2, ISRO's L&S- Band Airborne SAR (LS-ASAR) Quad-pol and Compact-pol datasets, and the RISAT-1 Compact-pol dataset. Calibration of the airborne PolSAR data was carried to understand the level of polarimetric distortions in the LS-ASAR product that is a precursor mission to the spaceborne Dual-Frequency L&S Band NASA-ISRO Synthetic Aperture Radar (NISAR) mission. It is understood that the crosstalk is the dominant polarimetric distortion, which severely affects the PolSAR datasets compared to the other polarimetric distortions, and it is more for the higher wavelength PolSAR systems. The Quegan, Improved Quegan, and Ainsworth algorithms for crosstalk estimation and minimization was performed for the different Quad-pol datasets and it was found that the Improved Quegan algorithm is suitable for removing crosstalk from datasets having high crosstalk and the Ainsworth algorithm is suitable for removing crosstalk from datasets having low crosstalk. The Freeman method of the polarimetric calibration was implemented for the compact-pol datasets and it was able to considerably minimize the polarimetric distortions. The coherency matrix, scattering matrix, model-based decomposition, polarimetric signatures, and roll invariant parameter-based analysis revealed that all the datasets after polarimetric calibration were showing the correct scattering responses expected from the ground targets.","Ainsworth algorithm; Channel imbalance; Crosstalk; CTLR; Faraday rotation; Freeman algorithm; Improved Quegan algorithm; NASA-ISRO Synthetic Aperture Radar (NISAR); Phase bias; Polarimetric decomposition; Quegan algorithm; Spaceborne PolSAR","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","","","Mathematical Geodesy and Positioning","","",""
"uuid:6c1f0979-c4ce-4fbe-bd17-8c79ddb7920e","http://resolver.tudelft.nl/uuid:6c1f0979-c4ce-4fbe-bd17-8c79ddb7920e","WhiskEras 2.0: Fast and Accurate Whisker Tracking in Rodents","Arvanitis, P. (TU Delft Quantum & Computer Engineering; Erasmus MC); Betting, Jan Harm L.F. (Erasmus MC); Bosman, Laurens W.J. (Erasmus MC); Al-Ars, Z. (TU Delft Quantum & Computer Engineering; TU Delft Computer Engineering); Strydis, C. (Erasmus MC)","Orailoglu, Alex (editor); Jung, Matthias (editor); Reichenbach, Marc (editor)","2022","Mice and rats can rapidly move their whiskers when exploring the environment. Accurate description of these movements is important for behavioral studies in neuroscience. Whisker tracking is, however, a notoriously difficult task due to the fast movements and frequent crossings and juxtapositionings among whiskers. We have recently developed WhiskEras, a computer-vision-based algorithm for whisker tracking in untrimmed, head-restrained mice. Although WhiskEras excels in tracking the movements of individual unmarked whiskers over time based on high-speed videos, the initial version of WhiskEras still had two issues preventing its widespread use: it involved tuning a great number of parameters manually to adjust for different experimental setups, and it was slow, processing less than 1 frame per second. To overcome these problems, we present here WhiskEras 2.0, in which the unwieldy stages of the initial algorithm were improved. The enhanced algorithm is more robust, not requiring intense parameter tuning. Furthermore, it was accelerated by first porting the code from MATLAB to C++ and then using advanced parallelization techniques with CUDA and OpenMP to achieve a speedup of at least 75x when processing a challenging whisker video. The improved WhiskEras 2.0 is made publicly available and is ready for processing high-speed videos, thus propelling behavioral research in neuroscience, in particular on sensorimotor integration.","Acceleration; Algorithmic improvement; Whisker tracking","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.","","2023-07-01","","Quantum & Computer Engineering","Computer Engineering","","",""
"uuid:3cc141f9-8cc1-457b-8426-d189cf3a3386","http://resolver.tudelft.nl/uuid:3cc141f9-8cc1-457b-8426-d189cf3a3386","Design-Relevant Factors Affecting the Patient Experience in Digital Health: Preliminary Results of an Umbrella Systematic Review","Wang, T. (TU Delft Applied Ergonomics and Design); Giunti, Guido (TU Delft Applied Ergonomics and Design; University of Oulu); Melles, M. (TU Delft Applied Ergonomics and Design); Goossens, R.H.M. (TU Delft Human-Centered Design; TU Delft Applied Ergonomics and Design)","Otero, Paula (editor); Scott, Philip (editor); Martin, Susan Z. (editor); Huesing, Elaine (editor)","2022","Since Covid-19, digital health interventions (DHIs) have been embraced as never before. The pandemic led to many new challenges, including the patient experience in digital health care delivery. In this literature study, we identified and synthesized factors that impact patient experience in digital health (dPEx), and reviewed the methods and strategies relevant to its design and implementation. We conducted an umbrella review including 15 reviews representing 543 studies. Four themes were identified that describe design-relevant factors that impact dPEx: individual context, content, technical issues, and design features. We propose a preliminary framework to explain the relationship between each factor and support user-centered design efforts. Further research is needed to identify which factors have the most impact.","Quality Improvement; Telemedicine; User-centered Design","en","conference paper","IOS Press","","","","","","","","","Human-Centered Design","Applied Ergonomics and Design","","",""
"uuid:181c5136-52f5-4054-b558-c11dfc65c53b","http://resolver.tudelft.nl/uuid:181c5136-52f5-4054-b558-c11dfc65c53b","A Front-end ASIC with Resolution Improvement Technique for Doppler Signal Observation in Ultrasound Brain Imaging","Zhang, Yixin (TU Delft Electrical Engineering, Mathematics and Computer Science)","Pertijs, M.A.P. (mentor); Delft University of Technology (degree granting institution)","2021","In this design, we propose a new method to process the large static signal in the received signal of Doppler ultrasound brain imaging. Through a reproduction-compensation method, a medium resolution ADC and a DAC are used to replace the high-resolution ADC used in the past for the dynamic Doppler signal observation.","Doppler brain ultrasound; large signal compensation; resolution improvement; high DR signal","en","master thesis","","","","","","","","","","","","","",""
"uuid:b70e5a10-fc58-4a9e-ad5f-496f97211cd6","http://resolver.tudelft.nl/uuid:b70e5a10-fc58-4a9e-ad5f-496f97211cd6","Circular Yacht Production: Mapping environmental impacts of business processes in yacht building and indicating innovation potential","Ettema, Bart (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Ship Design, Production and Operations)","Pruijn, J.F.J. (mentor); Beelaerts van Blokland, W.W.A. (graduation committee); Verhoeff, Wim (graduation committee); de Maeyer, Evy (graduation committee); Delft University of Technology (degree granting institution)","2021","The yacht building industry is considered an industry with a high environmental impact. Until now, the focus has not been on the impact regarding business processes of the building phase and the excess in resources that are used, ultimately not adding value to the final product. Due to emerging trends in regulations, new sustainable production processes are investigated, ensuring that forms of waste can be reduced and a circular production approach is encouraged. In this thesis, an environmental value stream mapping (EVSM) approach is used in combination with the Eco-indicator99 calculation method to map and assess the environmental impacts of production processes. The EVSM approach is known for the identification regarding improvements in production phases to ultimately propose innovations in future states. The Eco-indicator99 calculation method ensures that various environmental impacts can be related to each other through assigned Ecopoints. This thesis includes the elaboration of a case study by making use of a created methodology towards the reduction of the environmental impact at a yacht building company. Confirming the ability to identify, assess and compare forms of impact and to point out potential innovation areas. The case study supports the feasibility of the proposed EVSM approach of a structured indication and supports the reduction of the environmental impacts present, thereby improving the sustainable performance, efficient use of resources and reduction of costs.","Circularity; Circular Economy; Yacht Building; Sustainabilty; Environmental impact; Business Process Improvement","en","master thesis","","","","","","","","","","","","Marine Technology | Ship Design, Production and Operations","",""
"uuid:5d75ba30-0ebc-47ce-9c64-75a65a88dbe5","http://resolver.tudelft.nl/uuid:5d75ba30-0ebc-47ce-9c64-75a65a88dbe5","Single-Channel Heterogeneous-Source Energy Harvesting PMIC Design","van der Velden, Joram (TU Delft Electrical Engineering, Mathematics and Computer Science)","Serdijn, W.A. (mentor); Campos Martins, G. (mentor); Du, S. (graduation committee); Delft University of Technology (degree granting institution)","2021","class=""MsoNormal"">This work proposes an energy harvesting platform that is able to convert power from both DC sources (photo-voltaic cells and TEGs) as well as piezo element sources. It does so only using a single input channel to which a single harvester can be connected. The proposed system is able to differentiate between the two source types and adjust the power converter configuration accordingly.For the DC sources, a novel switched-capacitor power converter (SCPC) is proposed, that is able to convert the energy from a harvester that has a maximum power point (MPP) output voltage of 170mV to 5V and a maximum power point output power of 10uW to 50mW. This DC-DC converter offers 119 different positive voltage conversion ratios, with a maximum voltage conversion ratio of 16, using four in-package capacitors. As a result of this high number of conversion ratios, the MPP output voltage of the harvester and the input voltage of the power converter are matched accurately, causing the harvesting efficiency to be very high. A maximum harvesting efficiency of 96.2% is found in simulations. For the piezo element sources, the concept of a flipping-capacitor rectifier (FCR) has been adjusted to work in harmony with the designed SCPC. In a steady-state condition, the capacitors of the SCPC reach specific voltages, such that they can create evenly spaced voltage steps for the flipping operation. With this technique, a voltage flipping efficiency of 0.9375 and a theoretical maximum output power improvement rate (MOPIR) of 32 can be reached. Due to losses in the system, simulation results show a MOPIR of up to 20.0, which is still significantly higher than the state-of-art. The system is designed to work with harvesters with a piezo capacitance of up to 100nF, an excitation frequency of 1Hz to 200Hz and an equivalent FBR maximum power point output power of 1uW to 50mW. An implementation of the proposed system is discussed and simulated. The total active silicon area for the designed system is 2.12mm2 in a 0.18 um TSMC technology.
The thesis starts with a literature study on eight business process improvement methodologies (BPIs), viz. Lean, Six Sigma, Lean Six Sigma, Total Quality Management, Lean MRO, Total Productive Maintenance, Business Process Reengineering, and Business Process Improvement. These BPIs are compared with each other in an overview based on nine characteristics. Then, a ninth BPI is studied: process mining. The literature on this topic is scattered, but a study is conducted on several element. After that, pros and cons are discussed and process mining is placed in the overview of BPIs.
A combination of desk and field research leads to the improvement of the best practise methodology PM2. And this improved methodology, called PM3, is further within MoD. Next to that, a process mining decision framework is developed according to the waterfall model. This framework can score business process models on several characteristics. The resulting total score determines whether process mining can successfully be applied to improve the process.
For MoD, process mining can be a valuable instrument for improving processes. It can convert a gut feeling into clear numbers and models, which can form the start of an improvement project. It is thus recommended to make process mining available to the organisation.
The thesis gives a good insight in the possibilities of process mining, but it also comes with several opportunities for future research. For example, PM3 has demonstrated itself in the field, but this have not yet led to measurable improvements (only important insights in the processes). Future research is required to verify its true potential. Second, the decision framework is tested by assessing fourteen of MoD’s processes and evaluated by discussion it with ten system experts. Yet again, empirical research is probably the only way to truly verify it, but this was not possible during the thesis. Third, both PM3 and the decision framework focus on MRO within MoD. It is unlikely that a change of domain or organisation makes a significant difference, but the possibility should be taken into account and further investigated. And finally, a significant limitation of the framework is that it only scores on process mining. So, if it presents a very low score, it does not suggest an alternative BPI. This fell outside the scope of the thesis, but is nevertheless an interesting research opportunity.
Scaled down experiments were performed in a water channel, housed in the Laboratory for Aero and Hydrodynamics at the Delft University of technology. Simultaneous measurements of the flow velocities and dye intensities in the symmetry-plane of the channel were made through planar Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF). A few flow configurations were studied by varying certain parameters. It was found that: (a) ESP installation is more beneficial on top of shorter sound barriers. (b) Slightly raising the ESP from the top of the sound barrier is advantageous. (c) Installation of ESPs in isolated highway canyons should be done with care, as several flow regimes are observed.
First order estimates on the aerodynamic efficiencies of the ESP were determined. This was accompanied by the identification of ESP performance trends that should serve as a guideline for the initial testing of the ESPs at full scale. The guidelines include the physical location and entrance orientation of the ESP. It is known that the collection efficiency of the ESP is a function of the incoming flow velocity. It is recommended that the entrance flow velocities reported here be used as an input for calculating the associated particle collection efficiency. Together, the collection and aerodynamic efficiencies can be used to estimate the overall efficiency of the ESP. If the overall efficiency satisfies a minimum desirable threshold, the field experiments yield promising results, the device clears safety requirements, and the benefits outweigh the costs, the ‘Open Air Line ESP’ can be installed along the highways en masse in the future.","Pollution dispersion; Scaled down experiments; Aerodynamics; Particle Image Velocimetry; Laser Induced Fluorescence; Particulate Matter; Air quality improvement; Electrostatic Precipitators; Sound barriers; Highways","en","master thesis","","","","","","","","","","","","","",""
"uuid:5ade9836-fc21-4889-a328-bd3ef7062f12","http://resolver.tudelft.nl/uuid:5ade9836-fc21-4889-a328-bd3ef7062f12","Discovering the Potential of Risk-based Critical Chain Project Management in the Maritime Industry","van Bouwelen, Björn (TU Delft Mechanical, Maritime and Materials Engineering; TU Delft Marine and Transport Technology)","Hopman, J.J. (graduation committee); Coenen, J.M.G. (mentor); Veeke, H.P.M. (graduation committee); Henstra, Wouter (graduation committee); Delft University of Technology (degree granting institution)","2017","There is a never-ending quest to search for better ways of planning and controlling projects. Currently the majority of all projects are planned with the critical path method and controlled using earned value management. This way of planning and controlling projects has been used for decades now and can be seen as traditional project management (PM). This current PM paradigm does not work well enough for one-off projects. Risk assessment and risk management are not sufficiently covered in most standard PM methods. This thesis looks at the potential of critical chain project management (CCPM) in combination with extensive risk management techniques for improving project performance. The thesis will cover the development of a risk-based critical chain project management (RCCPM) methodology and its application to case studies at a shipyard. The study concludes that RCCPM is a viable alternative for traditional PM in the maritime industry. Improvements include, amongst others, a reduction of the lead-time, more effective monitoring and controlling, and improved dealing with risks and uncertainties.","Critical chain project management; Project management; Process improvement; Project risk management; Project planning; Uncertainty; Monte Carlo simulation; Shipbuilding","en","master thesis","","","","","","","","2022-08-23","","","","Marine Technology | Ship Design, Production and Operations","SDPO.17.026.m",""
"uuid:7f80e883-936c-4abe-ac4b-2c5c15e9cb1f","http://resolver.tudelft.nl/uuid:7f80e883-936c-4abe-ac4b-2c5c15e9cb1f","The potential of advanced data analytics using machine learning to increase overall equipment effectiveness in an underground mining operation","Wansink, Jan-Douwe (TU Delft Civil Engineering & Geosciences; TU Delft Geoscience and Engineering)","Buxton, M.W.N. (mentor); Delft University of Technology (degree granting institution)","2017","Changing market dynamics make that mining companies need to increase their equipment utilization and use their equipment more effectively. The growing availability of data from mining equipment and mining operations enables the use of data analytics to achieve that goal. This thesis explores the potential of data analytics and machine learning to increase equipment utilization through the means of a case study on an underground South African diamond mine. To identify and quantify the potential of data analytics for operational improvement a benchmarking analysis of the operation was done using operational equipment effectiveness (OEE) as a measure. The outcome of this indicated that there was significant value to be unlocked if unplanned breakdowns were mitigated and unscheduled maintenance could be moved into scheduled maintenance. This led to believe that there was a solid case for breakdown prediction based on equipment sensor data using advanced analytical techniques. Data availability and quality made that the proof-of-model was initiated for one 10 ton loader with the target components for breakdown prediction being the engine, transmission and brakes. After extensive data cleaning and preparation various machine learning algorithms adopted from various non-mining disciplines were used for training predictive models. The best result was yielded using support vector machines (SVM) showing a very high accuracy (>80%) with little misclassifications. Random forests and anomaly detection were also tried but the unbalanced and noisy nature of the data made for the performance of these models not leading to satisfactory levels. The results of this modelling exercise combined with the OEE analysis give enough confidence to accept the hypothesis that there is good potential for application of advanced analytics to increase the operational effectiveness of underground mining equipment.","OEE; Operational Equipment Effectiveness; Machine Learning; Failure Prediction; Predictive Maintenance; Mining; Underground Mining; LHD; Loader; Continuous Improvement; Random Forest; Support Vector Machines; Unbalanced Data; R; SMOTE","en","master thesis","","","","","","","","2022-08-21","","","","Applied Earth Sciences","",""
"uuid:1686e932-2df7-41df-80af-643d5a34fb2f","http://resolver.tudelft.nl/uuid:1686e932-2df7-41df-80af-643d5a34fb2f","Conformance Control in Heterogeneous Oil Reservoirs with Polymer Gels and Nano-Spheres","Lenchenkov, N. (TU Delft Reservoir Engineering; TU Delft Lab Geoscience and Engineering)","van Kruijsdijk, C.P.J.W. (promotor); Delft University of Technology (degree granting institution)","2017","In many oil fields, water is injected into a reservoir to displace oil to the production wells. During the injection process, oil is pushed by water towards production wells which have a lower pressure than the rest of the reservoir. If the reservoir is homogeneous, then a good sweep efficiency of the water flood process is expected. However, most oil reservoirs are stratified and that creates a permeability contrast along the whole height. High permeable layers take most of the injected water resulting in lower sweep efficiency of the other layers. The water breaks through the high permeable zones, significantly increasing the water cut of the produced fluid. Excessive produced water has to be treated in surface facilities which increase the costs of the extraction process. Another disadvantage of the low sweep of a reservoir is a significant amount of remaining oil behind the displacement front...","polymers; conformance control; improved oil recovery; nano-spheres; cross-linked polymers; flow in porous media; electron microscopy; dynamic light scattering","en","doctoral thesis","","978-94-6233-668-1","","","","","","","","","Reservoir Engineering","","",""
"uuid:72090752-81c2-44c1-a068-d329785f24fd","http://resolver.tudelft.nl/uuid:72090752-81c2-44c1-a068-d329785f24fd","Industrial relevance of chromosomal copy number variation in Saccharomyces yeasts","Gorter de Vries, A.R. (TU Delft BT/Industriele Microbiologie); Pronk, J.T. (TU Delft BT/Industriele Microbiologie); Daran, J.G. (TU Delft BT/Industriele Microbiologie)","","2017","Chromosomal copy number variation (CCNV) plays a key role in evolution and health of eukaryotes. The unicellular yeast Saccharomyces cerevisiae is an important model for studying the generation, physiological impact, and evolutionary significance of CCNV. Fundamental studies of this yeast have contributed to an extensive set of methods for analyzing and introducing CCNV. Moreover, these studies provided insight into the balance between negative and positive impacts of CCNV in evolutionary contexts. A growing body of evidence indicates that CCNV not only frequently occurs in industrial strains of Saccharomyces yeasts but also is a key contributor to the diversity of industrially relevant traits. This notion is further supported by the frequent involvement of CCNV in industrially relevant traits acquired during evolutionary engineering. This review describes recent developments in genome sequencing and genome editing techniques and discusses how these offer opportunities to unravel contributions of CCNV in industrial Saccharomyces strains as well as to rationally engineer yeast chromosomal copy numbers and karyotypes.","Aneuploidy; Evolutionary adaptation; Fermentation; Genome engineering; Industrial yeast; Industrial yeast fermentation; Strain improvement","en","journal article","","","","","","","","","","","BT/Industriele Microbiologie","","",""
"uuid:c93d7002-911b-4508-84b3-faa4490fc4f7","http://resolver.tudelft.nl/uuid:c93d7002-911b-4508-84b3-faa4490fc4f7","Improving the operational availability of the ships of the Royal Netherlands Navy","van Donkelaar, A.","Veeke, H.P.M. (mentor); Driegen, F.J. (mentor)","2017","The current developments in the world result in increasing tensions between different countries. This increasing tension requires materials that are available when needed. Major budget cuts have resulted in the disposal of six multipurpose frigates which has reduced the total amount of frigates owned by the Royal Netherlands Navy from twelve to six. Because of this significant reduction, a high availability of the remaining frigates and oceangoing patrol vessels is required. However, the availability of these vessels is not sufficient at the moment. In this research a suitable definition for the term 'availability' was found in the term 'operational availability' which is a function of the maintenance process. With this definition the operational availability of the multipurpose frigates, air defence and command frigates and oceangoing patrol vessels was calculated. The calculation showed that the operational availability of these ships does not meet the operational availability requirements. The maintenance process was analysed by using the Delft Systems Approach to determine the problems that cause the low operational availability of the ships. The analysis showed a significant amount of problems that influence the operational availability of the ships in a negative way. This study developed a continual process improvement dashboard that can be used by the Royal Netherlands Navy as a tool to improve the operational availability of their existing ships. Besides that, the dashboard can also be used in the design process of a new ship class to achieve the desired operational availability for the new ships.","Operational Availability; Delft Systems Approach; Continuous Process Improvement; Royal Netherlands Navy","en","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","","Transport Engineering and Logistics","",""
"uuid:317ded61-5c43-4b0e-bb2a-ef9fc5dba502","http://resolver.tudelft.nl/uuid:317ded61-5c43-4b0e-bb2a-ef9fc5dba502","Process improvement to shorten the lead-time for the ACD division in the distribution center of L’Oreal located in Alphen aan den Rijn","Jacquemijns, J.","Negenborn, R.R. (mentor)","2017","The thesis is about process improvements in L’Oréal’s distribution center. A framework is developed based on the DMAIC approach, process improvement methodologies and solution evaluation methodologies. The current process is discussed and with the Lean Six Sigma philosophy measures of improvement are developed. The requirements for the improvements were creating flow, reducing waiting time and providing insights. Five different improvements were developed and the dynamic wave and resource planning improvement scored the highest. This improvement provides a tool for the supervisors and team-leaders to prioritize work and manage the employees in a better way. A simulation was conducted to quantify the lead-time improvement. This simulation resulted in a reduction in lead-time of 5 till 47% bringing the average lead-time down from 2.2 to 1.5 days.","process improvement; distribution center; warehouse; capacity; lead-time reduction; L'Oréal","en","master thesis","","","","","","","","2017-03-09","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","","Transport, Infrastructure and Logistics","TIL5060",""
"uuid:060d9f3e-561c-4806-87fb-dd378cfaf3b0","http://resolver.tudelft.nl/uuid:060d9f3e-561c-4806-87fb-dd378cfaf3b0","Adaptive efficient global optimization of systems with independent components","Rehman, S.U. (TU Delft Computational Design and Mechanics); Langelaar, Matthijs (TU Delft Computational Design and Mechanics)","","2017","We present a novel approach for efficient optimization of systems consisting of expensive to simulate components and relatively inexpensive system-level simulations. We consider the types of problem in which the components of the system problem are independent in the sense that they do not exchange coupling variables, however, design variables can be shared across components. Component metamodels are constructed using Kriging. The metamodels are adaptively sampled based on a system level infill sampling criterion using Efficient Global Optimization. The effectiveness of the technique is demonstrated by applying it on numerical examples and an engineering case study. Results show steady and fast converge to the global deterministic optimum of the problems.","Efficient global optimization; Expected improvement; Gaussian processes; Infill sampling; Kriging; System optimization","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:50d919e3-ba70-4768-92f3-31471bcf58c0","http://resolver.tudelft.nl/uuid:50d919e3-ba70-4768-92f3-31471bcf58c0","Expected improvement based infill sampling for global robust optimization of constrained problems","Rehman, S.U. (TU Delft Computational Design and Mechanics); Langelaar, Matthijs (TU Delft Computational Design and Mechanics)","","2017","A novel adaptive sampling scheme for efficient global robust optimization of constrained problems is proposed. The method addresses expensive to simulate black-box constrained problems affected by uncertainties for which only the bounds are known, while the probability distribution is not available. An iterative strategy for global robust optimization that adaptively samples the Kriging metamodel of the computationally expensive problem is proposed. The presented approach is tested on several benchmark problems and the average performance based on 100 runs is evaluated. The applicability of the method to engineering problems is also illustrated by applying robust optimization on an integrated photonic device affected by manufacturing uncertainties. The numerical results show consistent convergence to the global robust optimum using a limited number of expensive simulations.","Efficient global optimization; Expected improvement; Kriging; Robust optimization","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:fb68ecf3-7b7e-4c3f-b20b-260f1832c89c","http://resolver.tudelft.nl/uuid:fb68ecf3-7b7e-4c3f-b20b-260f1832c89c","Incorporating Air Quality Improvement at a Local Level into Climate Policy in the Transport Sector: A Case Study in Bandung City, Indonesia.","Gunawan, Helmi (University of Twente); Bressers, Hans (University of Twente); Mohlakoana, Nthabi (University of Twente); Hoppe, T. (TU Delft Organisation & Governance)","","2017","Climate policy has a strong influence on policy processes at national levels in Indonesia, while other policies with a focus on air quality improvement are being implemented at local levels. Indonesia as a developing country has committed to reducing greenhouse gas (GHG) emissions by 29 percent by the year 2030. This calls into question the extent to which cities and local governments can cope with the challenges of climate change mitigation. The purpose of the research is to find out the extent to which local air pollution reduction policies can contribute to the climate change mitigation program. The research design involved an empirical case study on governance and policy
relevant to climate change efforts to lower GHG in Bandung City, Indonesia. The study evaluated the air quality improvement and the climate change mitigation programs using the actor-based framework of the Contextual Interaction Theory (CIT). The governance and stakeholder characteristic of climate change mitigation were also analysed using the structural context part of the CIT framework. The result shows that air quality improvement policy is implemented separately from climate policy; the latter operates at the national level and the former at the local level. By looking at the actor interaction analysis, the study concludes that a more holistic environmental policy approach would be more efficient at reducing local air pollution and contributing to the mitigation of climate change.","air quality improvement; climate change mitigation; local government; contextual interaction theory; co-benefit goals","en","journal article","","","","","","","","","","","Organisation & Governance","","",""
"uuid:4f91b8c7-df3b-4142-aea5-d342e6b69028","http://resolver.tudelft.nl/uuid:4f91b8c7-df3b-4142-aea5-d342e6b69028","Effectiveness of energy renovations: a reassessment based on actual consumption savings","Filippidou, F. (TU Delft OLD Housing Quality and Process Innovation); Nieboer, N.E.T. (TU Delft OLD Housing Quality and Process Innovation); Visscher, H.J. (TU Delft OLD Housing Quality and Process Innovation)","Laitinen Lindström, Therese (editor); Blume, Ylva (editor); Regebro, Margareta (editor); Hampus, Nina (editor); Hiltunen, Vanja (editor)","2017","Energy renovations offer unique opportunities to increase the energy efficiency of the built environment and for the existing housing stock, they are the most important solution. Usually, energy savings are based on modelling calculations. However, recent research has shown that the predicted energy consumption differs largely from the actual consumption. In this paper, the effectiveness of energy measures is re-assessed based on actual consumption data. We use a monitoring system, which contains information about the energy performance of around 60% of the Dutch non-profit housing sector (circa 1.2 million dwellings). We connect the data from this monitoring system to actual energy consumption data from Statistics Netherlands on a dwelling level. Using longitudinal analysis methods, from 2010 to 2014, we are able to identify the energy efficiency improvements of the stock and determine the effectiveness of different measures in terms of actual energy savings. The results reveal the actual energy savings of different efficiency measures and highlight the significance of the actual energy consumption when a renovation is planned or realized.","energy efficiency improvements; monitoring; energy savings; non-profit housing","en","conference paper","European Council for an Energy Efficient Economy (ECEEE)","","","","","","","","","","OLD Housing Quality and Process Innovation","","",""
"uuid:3ecd2f62-8145-4630-bd48-dbfb0157a8a5","http://resolver.tudelft.nl/uuid:3ecd2f62-8145-4630-bd48-dbfb0157a8a5","Dynamic Analysis of a subsea cable during cable installation: Improving operability of the cable installation for shallow and deep water","Bui, N.C.","Metrikine, A. (mentor); De Oliveira Barbosa, J.M. (mentor); Jarquin Laguna, A. (mentor); Natarajan, G. (mentor); Visser, C. (mentor); Hassan, M. (mentor)","2016","The investigation into the dynamic behavior of a cable during installation was done with the aim of improving cable installation for safety, operational and commercial value. In order to increase the operational limit of the vessel during cable installation, the investigation into improvement systems was desired. The workability of a vessel during cable laying operations is governed by the cable integrity design criteria such as maximum tension, touch-down-point tension, side-wall-pressure and the minimum bending radius. In practice during cable-laying the touch-down-point tension and minimum bend radius cannot be measured. Therefore a dynamic analysis of the subsea cable is required to determine the cable motions and tension fluctuations. The main objective of this Master Thesis is to develop and investigate two cable lay improvement systems. Both systems are modeled in OrcaFlex software to analyze its improved effect on the workability during cable laying operations. The cable integrity design conditions are compensated by either active force control at the tensioner systems or by active position control near the departure point on the chute. By controlling one of the two parameters the catenary shape is stabilized and therefore the fluctuating tension and cable motions are controlled. Force control is developed in OrcaFlex by a Tensioner System controlling the tensions in the load cells at a target value, position control is controlling the chute-end location with an Active Heave Compensated Chute System. To actively control the improvement systems, a Proportional-Integral-Derivative (PID)-Controller is used in OrcaFlex as external function where the performance dependents on the defined PID-Parameters. To optimize the improvement systems further, first simplified 1-Degree Of Freedom (DOF) analytical position controlled models are developed to identify the initial guess PID-Parameters. Subsequently, a 6-DOF position (left picture) and force (right picture) controlled models in OrcaFlex, was developed and simulated using the obtained initial guess PID-Parameters. In OrcaFlex the PID-Parameters are further adjusted using regular wave theory to achieve the full performance capacity of the improvement systems based on data obtained from existing systems on the market. Finally a detailed numerical model is developed and analyzed for irregular wave heights to obtain the workability plots. The numerical models are subjected to environmental and hydrodynamic loads during a three-hour simulation. Results show that the force and position controlled systems are able to improve the cable integrity design conditions significantly, but more for the position controlled system. The force controlled system is limited by the pay-out velocity for deep water and by cable compression and the minimum bending radius at shallow water, whereas the position controlled system is limited by the stroke of the cylinder. Also it has been found that the controller performance for the force controlled system must be adjusted for different range of waterdepth, while the position controlled system maintains the same performance. Furthermore, the position controlled system is able to hold the catenary shape nearly still, significantly more that it does for the tension controlled system. In conclusion an increased workability during cable installation can be achieved with one of the improvement systems.","cable; workability; improving; tensioner system; heave compensated chute; OrcaFlex; PID-Controller; Tension; compression; minimum bend radius; side wallpressure; catenary shape; integrity","en","master thesis","","","","","","","","2021-11-07","Civil Engineering and Geosciences","Hydraulic Engineering","","Offshore and Dredging Engineering, specialisation: Bottom Founded Structures, Artic & Wind","",""
"uuid:c08c31c0-0c36-4d00-9a86-7fb532a1379e","http://resolver.tudelft.nl/uuid:c08c31c0-0c36-4d00-9a86-7fb532a1379e","The necessities to improve water recreation on the Mill Creek in Walla Walla","van Hoof, S.","Verhagen, H.J. (mentor); Sloff, C.J. (mentor)","2016","In Walla Walla, Washington the Mill Creek flows through an outdated concrete spillway that needs renovation. The city council of Walla Walla saw this as an opportunity to further develop this channel. Their desires include conservation of the fish ladder, enabling to sail by boat and to prettify the spillway. A Sobek 1D model was built to give a proper insight of the current situation. To verify the model calibration was done by using USGS data and GIS maps of the Walla Walla council. Also various design alternatives were specified to see which form of recreation is most feasible. The results from the model in the current situation showed that the water depth was too low while its velocity was too high for the different vessels. To solve this issue, an upgrade for the concrete spillway was proposed. By roughening the riverbed and placing groynes into the creek, the water depth increased and the water velocity dropped, according to the improved model. However, the design is a rough sketch that forms the base for a more detailed study. It is recommended to continue improving the model to verify the results which are presented in this report to be sure the proposed upgraded design will contribute to the desires.","River improvement; Sobek; Washington State","en","bachelor thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","","46.068084, -118.328963"
"uuid:57010309-6d13-4766-ab16-1902af5778fd","http://resolver.tudelft.nl/uuid:57010309-6d13-4766-ab16-1902af5778fd","Designing a seamless passenger journey: Picking up luggage from origin to destination and back","Marie, A.H.L.","Bergema, C.P.A.M. (mentor); Ottens, R. (mentor)","2016","Royal Dutch Airlines (KLM) and the Technical University Delft, faculty Industrial Design Engineering (IDE) are working together on the Personalised Airport System for Seamless Mobility and Experience (PASSME) project.. There are two problems derived from the PASSME project. First, airport processes are not seamless, because passengers spend relatively much unwanted time at the airport. PASSME’s objective is to reduce the time spent on handling luggage by 30 minutes. Secondly, the current state of luggage check-in for passengers is experienced as negative in 21% of the cases. It is experienced as heavy, a hassle and it creates stress. PASSME aims to improve the entire quality of experience of the door-to-door journey for at least 70% of the passengers. During the internal research at KLM, different problems were found at the luggage check-in. Passengers spend on average 6 minutes and 11 seconds at the SSDOP and 9 minutes and 50 seconds at the CUDOP. When researching the current situation for passengers several things can be concluded. A quantitative research is performed (n=86) to research the experience passengers have during their passenger journey with check-in luggage. From the research it can be deduced that passengers travelling by public transport, experience the journey less positively (4.7 out of 7), than passengers who use other types of transportation (car 5.9 out of 7, taxi 6.2 out of 7). These passengers need to travel with their check-in luggage by train, bus, metro and other public transports to reach the airport. And this travelling on public transport with their check-in luggage, causes a more negative experience and emotions, because carrying the luggage from bus to train or storing the luggage, is experienced as not very positive. After this research it became clear where improvement was possible for passenger and airline. The experience can be improved for passengers who travel by public transport. Unwanted airport time can be reduced at the luggage check-in and at the reclaim belt. The solution is a door-to-door luggage service. The luggage is picked-up by a logistic partner at the home address of the passenger. The luggage is transported by a logistic partner to the accommodation of the passenger. This means that the luggage is removed out of the passenger journey from home to airport. The door-to-door luggage service improves the passenger experience when travelling to the airport by public transport from a 4.7 to 6.3. Because of this service, the passenger does not have to handle the check-in luggage anymore from origin to airport. Since this service removes the check-in luggage from the airport, the passenger does not have to spend time at the luggage check-in area nor at the reclaim area. In total, the waiting time and processing time for passengers can be reduced from 29 minutes to 34 minutes, when the door-to-door service is used.","seamless flow; KLM; luggage; door-to-door; passenger journey; improve experience; reduce unwanted airport time","en","master thesis","","","","","","","Campus only","","Industrial Design Engineering","Strategic Product Design","","","",""
"uuid:ebed9a0a-0fce-4005-8c0b-17455b2fa10d","http://resolver.tudelft.nl/uuid:ebed9a0a-0fce-4005-8c0b-17455b2fa10d","An Experimental Investigation on the Rock Mechanical Behavior of Synthetic Layered Systems and Load-Cycling of its Individual Constituents","Janmahomed, F.R.","Barnhoorn, A. (mentor)","2016","Many authors already made an attempt to understand the effect of load-cycling on material strength and the evolution of elastic parameters. However, until now there was no study on the effect of load-cycling on the evolution of elastic parameters over the complete stress strain curve, i.e. the linear elastic regime, the fracturing regime, and the fractured regime. In addition, none of the authors focussed on the effect of load-cycling on fracture network improvement. Although previous studies already showed that elastic moduli of layered systems may be determined from properties and volume fractions of its individual constituents, there is no study done on the relation between rock mechanical properties, i.e. strains and yield or failure stresses, of (synthetic) layered systems and its constituents. Furthermore, in the literature no description is found on fracture characteristics of a (synthetic) layered system. Hence, an experimental investigation is conducted on the rock mechanical behavior of synthetic layered systems subjected to increased-loading and the effect of load-cycling on its individual constituents’ rock strength, elastic parameter evolution, and fracture network improvement. The increased-loading and load-cycling rock mechanical experiments are unconfined compression tests performed at room temperature. When comparing two of the same rock materials with a maximum deviation of 1% in porosity, load-cycling leads to failure at much lower stress levels when compared to increased-loading. Within the linear elastic regime, load-cycling returns a stabilized Young’s modulus which is always larger than its envelope value, while the Poisson’s ratio of the last load cycle coincides with its envelope value. Load-cycling generates an improved fracture network when compared to increased-loading. Characteristics of the improved fracture network are the increased fracture densities and the more uniform distribution of the fractures over the volume of the material. For vertically stacked synthetic layered systems, the elastic moduli and strains can be well-predicted by the Reuss Average which uses the average rock mechanical properties and volume fractions of the individual constituents. In contrast, for synthetic layered systems the stress level at failure point is independent of the volume fractions of its constituents and is observed to be in the vicinity of its weakest constituent. Despite this, fractures are still observed in the strongest constituents. The fracture propagation through the strongest constituent is ascribed to be due to amplified stress concentrations at the tip of the propagating fracture. However, from 2-layered systems it is observed that fracture propagation through the strongest constituent depends on the thickness of the weakest constituent. At the constituents’ boundary in synthetic layered systems, there is no offset in fracture path when going from one constituent to another nor is there a sudden change in aperture. However, there is a change in fracture inclination in a way such that the fracture inclinations of the individual constituents are respected. In addition, fractures in synthetics include cataclastics over the high porous intervals (±10-25%), while the same fracture is clean over the low porous intervals (±0,5-5%).","Rock Mechanics; Load-Cycling; Increased-Loading; Fracture Improvement & Characteristics","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","Petroleum Engineering","",""
"uuid:d40011ba-73d4-4f48-a76d-1abde874dddb","http://resolver.tudelft.nl/uuid:d40011ba-73d4-4f48-a76d-1abde874dddb","Residential energy rebound effect assessment by using serious games","Garay Garcia, O.","van Daalen, C. (mentor)","2016","Energy reduction has been on the political agenda since the last couple of decades. One of the most common policies to reduce energy consumption has been improving efficiency. However, the phenomenon called the rebound effect may threaten the effectiveness of policies aiming to reduce consumption by improving efficiency. The rebound effect is the process in which energy savings, after energy efficiency improvements, are lower than expected. The scientific community agrees on the existence of the rebound effect and the possibility to measure it. In spite of this agreement, the rebound effect has been catalogued by many scholars as a highly controversial concept. In fact, the two main controversies around the rebound effect are: its size and its importance for the policy making process. The main causes that have produced the rebound effect to be controversial are: methodological issues of previous attempts to assess the effect, different numeric definitions and fuzzy and different system boundaries. The main objective of this thesis research was to find a new and innovative methodology to assess the rebound effect in order to improve the methodological issues of previous attempts that have analyzed the rebound effect. As a result, in reducing the causes of controversies, the controversies themselves may be reduced as well. The methodology that seems to improve the mentioned methodological issues is serious games. Serious games have several advantages that seem to fit and solve the shortcomings of the previous attempts that have analyzed the rebound effect in the past. In particular, the NRG game is the specific serious game that was used to perform the actual assessment in this research. The NRG game was used to carry out a new rebound effect assessment. In doing so, 50 people played the game in two different groups in a way to perform a modified before/after analysis: one group of 25 people using a low efficiency house and 25 people using a high efficiency house. The conclusions of this assessment showed that the rebound effect was, indeed, detected to be present when the behavior of the two groups was compared. In fact, two main signs of the rebound effect were detected. First, having a low efficiency made the low efficiency group to reduce their energy consumption more than the high efficiency group. Second, having a high efficiency made the high efficiency group to increase their comfort level (a direct measure of the luxury level of their houses in the game) more than the low efficiency group. As a result, the rebound effect was detected by keeping track of the total energy consumption and comfort level of each player. In addition, some of the methodological issues of previous rebound effect assessments that have used before/after analysis were improved, for instance, the possibility to perform ex-ante assessments, the inclusion of psychological factors of people in the results without making inaccurate assumptions and the inclusion of more than just one energy services in the experiments, among others. As a result, serious games were proven to be a handy tool to assess and analyze the rebound effect, improving the quality of previous assessments. Despite having proved the usefulness of serious games in assessing the rebound effect, some limitations of this research were identified: the sample under study was not a good representation of the population, the reliability of the rebound effect size calculation is compromised, the findings of this assessment can’t be applied in a real life context and so forth.","rebound effect; serious games; before/after analysis; energy reduction; energy efficiency improvements","en","master thesis","","","","","","","","","Technology, Policy and Management","Multi Actor Systems","","Policy Analysis","",""
"uuid:7ec271ca-2a51-4b89-b4ef-9e2badeb0493","http://resolver.tudelft.nl/uuid:7ec271ca-2a51-4b89-b4ef-9e2badeb0493","Lowering the Turnaround time for Aircraft component MRO services: A case study at KLM Engineering & Maintenance","Van Rijssel, R.E.","Lodewijks, G. (mentor); Beelaerts van Blokland, W.W.A. (mentor); Van Duin, J.H.R. (mentor)","2016","In this thesis a framework is built to find flow improvement measures to lower the turnaround time for aircraft component MRO processes. This framework is tested in a case study at KLM E&M. The main research question that is answered in this research is: What flow improvement measures can be used to lower the turnaround time of components in aircraft component MRO processes such that the average turnaround time can be lowered from 21 to 10 days at KLM E&M? To create this framework, case studies of aircraft component MRO processes were analyzed. Four quantifiable characteristics were found, being: flow type, amount of repair paths, equipment criticality and the moment of work-scope determination. Afterwards applicable improvement theories were studied on these characteristics and a framework was created for aircraft component MRO process flow improvement. Hereafter, a case study process was researched using the DMAIC cycle. First of all, it is advised to introduce two new KPI's; the 'TAT-waiting time' and the 'On time start', to monitor the waiting time. Furthermore, it was found that the shop has a single piece flow, the process follows a single path, the equipment is not critical and that the work-scope is determined during the process. When these characteristics are put in the flow improvement framework, it can be seen that lean, lean in MRO and quick response manufacturing fit best for the case process. However, in the case process the work-scope determination should be moved forward to be able to plan the work better and create a pull process. The selected improvement theories were researched in more detail on flow improvement measures. By using a simulation model it was found that with a supermarket system with a capacity constraint, an increase in technician capacity, lower disruption times and amounts, it is possible to lower the total TAT of the case process to 10 days on average. It can therefore be concluded that the improvement framework works for this case. For further research it is recommended to investigate the use of other simulation software and expand the simulation model to the total component MRO supply chain. Furthermore, it is advised to test the framework on other processes within KLM E&M and at other aircraft component MRO companies.","flow improvement; lean; MRO; aircraft component; turnaround time; simulation; DES; simio; maintenance","en","master thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Transport Engineering and Logistics","","Transport, Infrastructure and Logistics","",""
"uuid:4ff08fbb-2bbe-40da-90b0-77b3075876cd","http://resolver.tudelft.nl/uuid:4ff08fbb-2bbe-40da-90b0-77b3075876cd","Improving sport rehabilitation","Rosales, J.R.","Goossens, R.H.M. (mentor); Minnoye, A.L.M. (mentor); De Vos, R.J. (mentor)","2016","Rev is the final design product service system that can help athletes rehabilitate from traumatic ankle injuries. It does so by calibrating strength and stability of the unaffected leg and comparing it with exercises of the affected leg.Therefore communicating strength percentages back to the athlete. This enables the ultimate goal of increasing strength performanc to a functional recovery.","improving; design; rehabilitation; sport","en","master thesis","","","","","","","Campus only","","Industrial Design Engineering","Applied Ergonomics and Design","","","",""
"uuid:c42267b8-d944-496c-9497-c6622b0bb447","http://resolver.tudelft.nl/uuid:c42267b8-d944-496c-9497-c6622b0bb447","Improving project monitoring in subcontracted production projects: The development and implementation of a functional control framework to support monitoring in subcontracted one of a kind production projects","De Jonge, W.P.N.","Pruyn, J.F.J. (mentor)","2016","This paper describes the development and implementation of a framework that localizes steady-state-monitoring in subcontracted mega-yacht-production processes. The control framework modelling this steady-state based on the Delft Systems Approach, strives for continuously improved project monitoring and is comprises subcontractor management- and project control strategies. The framework accompanied by a roadmap for indicator development, supported the implementation of performance indicators. The implementation of performance indicators inspired by the lean production perspective, resulted in improved project monitoring in subcontracted production projects. It has after deployment been proven that the framework contributed to improved project monitoring during outfitting. The effective implementation of five indicators reflecting on various wasteaspects in subcontracted production, demonstrated the potential for root cause analysis and process improvement.","Delft Systems Approach; control framework; production monitoring; subcontracted production project; improvement; performance measurement; mega-yacht-building; operations monitoring","en","master thesis","","","","","","","","2021-05-18","Mechanical, Maritime and Materials Engineering","Marine & Transport Technology","","Masters Ship Production (SDPO)","",""
"uuid:2b4afb5e-c179-43df-af58-a33c859fa26f","http://resolver.tudelft.nl/uuid:2b4afb5e-c179-43df-af58-a33c859fa26f","Efficiency of a Column Supported Embankment in Sabkha Soil","Lamoré, R.","Hicks, M.A. (mentor)","2016","This thesis report presents an investigation of a soil improvement technique that is being executed for a Van Oord project in Kuwait. The soil is improved by the use of a column supported embankment, consisting of sand columns installed in a soft soil layer and a sand platform. The efficiency of this method is defined in terms of stress transfer and settlement reduction. When the soil improvement is finished and the land will be used, there are conditions concerning bearing capacity and settlement behavior. To this extent two important parameters were defined. i.e. the incremental efficiency (the load increase in a sand column over the total surface load increase) and incremental settlement reduction ratio (the settlement of the improved soil over the settlement of the unimproved soil (i.e. soil that has not been improved by sand columns), under loading). To determine the efficiency of the soil improvement, a number of tests were performed on site. Tests included plate load tests (in this thesis referred to as zone load tests). The load tests were simulated in Plaxis, with the known load/settlement results the model could be benchmarked. Furthermore soil samples were taken and tested to determine the local soil characteristics. The parameters derived from the soil tests are also used in the Plaxis calculations. Plaxis allows for a step-by-step consolidation of the soft soil in which the columns were installed. It can be seen that the stress distribution changes for different stages of consolidation. The columns are first constrained by the very stiff soft soil layer (due to high excess pore pressures under loading). When the pore pressures dissipate the constraining stress is lowered and the column head expands. Under vertical loading the stress in the column head has a funnel shape, due to the displacements in the outer ring of the column head. Based on the Plaxis calculations it can be concluded that when a load is activated on top of a surface of soil that has been improved by the use of sand columns (with a center-to-center distance of three meters), given that the platform is thick enough, 60% of that load is transferred to the column. With a greater center-to-center distance between the columns that percentage decreases, e.g. 28% for a column spacing of five meters. Compared to existing theories by Hewlett and Randolph (1988) and Zaeske (2001) (it should be noted that most existing theories assume presence of geosynthetic reinforcement, which is not the case for this project) the calculated column force is relatively low. A minimal thickness of the sand platform is needed to facilitate maximum efficiency. The thickness as determined by the Plaxis calculations are lower compared to existing literature. With platform heights of up to seven meters no full arching was observed, however partial arching did occur as evidenced by the efficiency values.","CSE; Column Supported Embankment; Sabkha; Soil Improvement; Columnar Inclusion; Dynamic Replacement","en","master thesis","","","","","","","","2016-03-24","Civil Engineering and Geosciences","Section Geo-Engineering","","","",""
"uuid:cfb6a67e-48b1-4360-92c4-28a772881240","http://resolver.tudelft.nl/uuid:cfb6a67e-48b1-4360-92c4-28a772881240","ICT as enabler or inhibitor of Lean Six Sigma Process Improvement","Bras, J.A.","Aldewereld, H.M. (mentor); Janssen, M.F.W.H.A. (mentor); Warnier, M.E. (mentor); Verburg, Q. (mentor)","2016","","Lean Six Sigma; ICT; Inhibitor; duality of technology; enabler; improvement","en","master thesis","","","","","","","","2016-01-25","Technology, Policy and Management","Engineering Systems and Services","","Management of Technology","",""
"uuid:3cdd5d24-9d46-4e8b-aad4-9a415a40da31","http://resolver.tudelft.nl/uuid:3cdd5d24-9d46-4e8b-aad4-9a415a40da31","Development of the Generalised Hybrid Turbulence Model for RANS simulations","Meijers, P.C.","Uijttewaal, W.S.J. (mentor); Van Zuijlen, A.H. (mentor); Florentie, L. (mentor)","2016","Turbulence plays an important role in a broad range of engineering applications. In the industry RANS simulations are a common method for predicting turbulent flow. A broad range of RANS turbulence models have been developed over the past decades. For the assessment of complex three-dimensional flow fields Reynolds Stress Transport Models are a better choice than eddy viscosity models, even though their computational cost is higher. A hybrid model that combines the accuracy of the Reynolds Stress Transport Models with the computational speed of the eddy viscosity models could be a valuable tool in the design of structures subjected to complex three-dimensional flows. Therefore the development of such a hybrid model was the objective of this thesis. A literature study on existing RANS turbulence models showed that the Reynolds Stress Transport Models (RSTM) are the most physical but also the computationally most expensive models. The linear eddy viscosity models have a reduced computational cost, but are not capable of predicting flow features that are caused by the Reynolds stress anisotropy, since these models can not account for this anisotropy. The non-linear eddy viscosity models include extra anisotropy by means of higher order terms, but the coefficients in these models are calibrated using simple benchmark test cases, making their applicability to more complex flows uncertain. The Hybrid Turbulence Model (HTM) of Basara combines a RSTM with the formulation of the linear eddy viscosity models to reduce the computation time of the simulation. This hybrid model is also unable to account for Reynolds stress anisotropy just like the linear eddy viscosity models. The development of the Generalised Hybrid Turbulence Model (GHTM) in this thesis, was motivated by this deficiency of the HTM. This novel hybrid model combines a RSTM with the general formulation of the non-linear eddy viscosity models. By using multiple base tensors additional Reynolds stress anisotropy is included. The HTM and the Improved k-epsilon model The GHTM was implemented in OpenFOAM and three test cases were investigated with this new model. The simulations with the GHTM do not reach convergence, except when the full tensor base is considered. The simulations with the Improved k-epsilon model converge and yield more physical results for the U-bend test case, showing a recirculation zone, where the standard k-epsilon model does not predict this flow feature. A mesh refinement study showed that the grid size has no influence on the performance of the GHTM. Also the use of different gradient schemes or under-relaxation did not affect the convergence of the GHTM simulations. To improve the performance of the GHTM different smoothing techniques have been tested, since peaks in the model coefficients seemed to cause the instability of the simulations. The proposed smoothing methods are modifications of the original GHTM and are therefore not useful to improve the performance of the GHTM. A closer look at the properties of the tensors used in the GHTM for statistically two-dimensional flows showed that an error in trace of the mean rate of strain tensor cause the resulting Reynolds stress anisotropy tensor to be incorrect. This problem was solved by constructing more accurate cell face velocities which correspond to the known cell face fluxes. With these new face velocities the GHTM with N=2 converges for the two-dimensional cases, but the linear GHTM still does not converge. A further investigation of the performance of the GHTM for statistically two-dimensional flows showed that in that case the GHTM with N=2 is identical to the background RSTM. This shows that the GHTM with N>1 could only lead to a reduction in computation time for three-dimensional flows.","RANS; hybrid turbulence model; Reynolds stress anisotropy; non-linear eddy viscosity; improved k-epsilon model","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","Hydraulic Engineering","",""
"uuid:5f9f2f3f-0ad8-4f2e-be8e-cf615e56e32a","http://resolver.tudelft.nl/uuid:5f9f2f3f-0ad8-4f2e-be8e-cf615e56e32a","Energy efficiency measures implemented in the Dutch non-profit housing sector","Filippidou, F. (TU Delft OLD Housing Quality and Process Innovation); Nieboer, N.E.T. (TU Delft OLD Housing Quality and Process Innovation); Visscher, H.J. (TU Delft OLD Housing Quality and Process Innovation)","","2016","The existing housing stock plays a major role in meeting the energy efficiency targets set in EU member states such as the Netherlands. The non-profit housing sector in this country dominates the housing market as it represents 31% of the total housing stock. The focus of this paper is to examine the energy efficiency measures that are currently applied in this sector and their effects on the energy performance. The information necessary for the research is drawn from a monitoring system that contains data about the physical state and the energy performance of more than 1.5 million dwellings in the sector. The method followed is based on the statistical modeling and data analysis of physical properties regarding energy efficiency, general dwellings’ characteristics and energy performance of 757,614 households. The outcomes of this research provide insight in the energy efficiency measures applied to the existing residential stock. Most of the changes regard the heating and domestic hot water (DHW) systems, and the glazing. The rest of the building envelope elements are not improved at the same frequency. The results show that the goals for this sector will be hard to achieve if the same strategy for renovation is followed.","Energy efficiency improvements; Monitoring; Energy performance; Non-profit housing","en","journal article","","","","","","Accepted Author Manuscript","","2018-06-02","","","OLD Housing Quality and Process Innovation","","",""
"uuid:93a2994f-64a5-40f7-a2e8-235fb5e4109e","http://resolver.tudelft.nl/uuid:93a2994f-64a5-40f7-a2e8-235fb5e4109e","Load Concentration Factor Based Analytical Method for Optimal Placement of Multiple Distribution Generators for Loss Minimization and Voltage Profile Improvement","Shahzad, Mohsin (AIT Austrian Institute of Technology); Ahmad, Ishtiaq (AIT Austrian Institute of Technology); Gawlik, Wolfgang (Technische Universität Wien); Palensky, P. (TU Delft Intelligent Electrical Power Grids)","","2016","This paper presents novel separate methods for finding optimal locations, sizes of multiple distributed generators (DGs) simultaneously and operational power factor in order to minimize power loss and improve the voltage profile in the distribution system. A load concentration factor (LCF) is introduced to select the optimal location(s) for DG placement. Exact loss formula based analytical expressions are derived for calculating the optimal sizes of any number of DGs simultaneously. Since neither optimizing the location nor optimizing the size is done iteratively, like existing methods do, the simulation time is reduced considerably. The exhaustive method is used to find the operational power factor, and it is shown with the results that the losses are further reduced and voltage profile is improved by operating the DGs at operational power factor. Results for power loss reduction and voltage profile improvement in IEEE 37 and 119 node radial distribution systems are presented and compared with the the loss sensitivity factor (LSF) method, improved analytical (IA) and exhaustive load flow method (ELF). The comparison for operational power factor and other power factors is also presented.","loss minimization; voltage profile improvement; simultaneous optimal sizing; multiple distributed generatores (DGs); load concentration factor (LCF); operational power factor; primary distribution system; loss sensitivity factor (LSF); improved analytic (IA); exhaustive load flow (ELF)","en","journal article","","","","","","This article belongs to the Special Issue Distributed Renewable Generation.","","","","","Intelligent Electrical Power Grids","","",""
"uuid:32572621-db15-4b2c-a6d2-ba5b28972ed4","http://resolver.tudelft.nl/uuid:32572621-db15-4b2c-a6d2-ba5b28972ed4","System robust optimization of ring resonator-based optical filters","Rehman, S.U. (TU Delft Computational Design and Mechanics); Langelaar, Matthijs (TU Delft Computational Design and Mechanics)","","2016","Fabrication variations can have a detrimental effect on the performance of optical filters based on ring resonators. However, by using robust optimization these effects can be minimized and device yield can be significantly improved. This paper presents an efficient robust optimization technique for designing manufacturable optical filters based on serial ring resonators. The serial ring resonator is treated as a system which has computationally expensive (directional coupler section) and cheap components (ring section). Cheap mathematical models are constructed of the directional coupler sections in the resonators. The approximate system response based on the cheap model is then robustly optimized. The robust bandpass filter performance is compared against designs that do not take uncertainties into account. The optimality of the robust solutions is confirmed by simulating it on the expensive physical model as a post-processing step. Results indicate that the employed approach can provide an efficient means for robust optimization of ring resonator-based optical filters.","system optimization; Design for-manufacturing; expected improvement; integrated optics; Kriging; ring resonators; Robust optimization","en","journal article","","","","","","","","","","","Computational Design and Mechanics","","",""
"uuid:927678db-9839-492e-97a2-55821ff9828d","http://resolver.tudelft.nl/uuid:927678db-9839-492e-97a2-55821ff9828d","Improved ADRC for a Maglev planar motor with a concentric winding structure","Kou, Baoquan (Harbin Institute of Technology); Xing, Feng (Harbin Institute of Technology); Zhang, Chaoning; Zhang, L. (TU Delft Pattern Recognition and Bioinformatics; School of Electrical Engineering and Automation; Harbin Institute of Technology); Zhou, Yiheng (Harbin Institute of Technology); Wang, Tiecheng (Harbin Institute of Technology)","","2016","In the semiconductor industry, positioning accuracy and acceleration are critical parameters. To improve the acceleration speed of a motor, this paper proposes the moving-coil maglev planar motor with a concentric winding structure. The coordinate system has been built for the multiple degrees of freedom movement system. The Lorenz force method has been applied to solve its electromagnetic model. The real-time solving of the generalized inverse matrix of factors can realize the decoupling of the winding current. When the maglev height changes, the electromagnetic force and torque decreases exponentially with the increase of the air gap. To decrease the influence on control system performance by the internal model change and the external disturbance, this paper proposes an improved active disturbance rejection control (ADRC) to design the controller. This new controller overcomes the jitter phenomenon due to the turning point for the traditional ADRC, thus it is more suitable for the maglev control system. The comparison between ADRC and the improved ADRC has been conducted, the result of which shows the improved ADRC has greater robustness.","Concentric winding; Improved ADRC; Maglev planar motor; Robustness","en","journal article","","","","","","","","","","","Pattern Recognition and Bioinformatics","","",""
"uuid:aa2defb6-f0e4-48f6-ae31-8aa68355831e","http://resolver.tudelft.nl/uuid:aa2defb6-f0e4-48f6-ae31-8aa68355831e","Developing a decision support framework for planning and implementing Bring Your Own Device programme in organizations","Shah, N.K.","Hulstijn, J. (mentor); Van den Berg, J. (mentor); Klevink, A.J. (mentor); van Gils, W. (mentor)","2015","The trend of Bring Your Own Device (BYOD) is creating a new change related to enterprise IT in many organizations. The last years, especially from 2009 -2015 has resulted in proliferation of consumer device market consisting of new mobile devices with features which are very much similar to the features provided by PC workstations. The BYOD programme consisting of mobile devices is creating a change in the way employees use consumer IT to perform work related activities. The use of employee owned personalized devices has many some opportunities such as improving employee productivity, costs to procure hardware and employee satisfaction, It has changed the utilization of employee workplaces due to the facility of mobility. But, at the same time the use of personal mobile devices to perform work activites brings certain challenges such as lack of interoperability with existing IT in the organisation and security risks. Organisations are interested in implementing BYOD programme but they fail to take into consideration certain aspects such as sustainability and effectiveness of the programme. To gain competitive advantage many organization haphazardly implement BYOD programmes for employees without considering the possible consequences and intricacies related to the programme. The research goal is to offer a decision support framework for organizations to plan and implement BYOD programme in organizations. The framework uses strategy ‘opportunities must be greater than risks’ and consists of iterative blocks. The Key performance indicators from the framework guide the decision maker to support a decision towards planning and establishing an effective BYOD programmes.","BYOD; decision support; IT change management; BYOD framework; process improvement","en","master thesis","","","","","","","","2016-11-30","Technology, Policy and Management","ICT","","Management of Technology","",""
"uuid:b441421a-8437-4e4f-b3fd-afb8c1f0b3b1","http://resolver.tudelft.nl/uuid:b441421a-8437-4e4f-b3fd-afb8c1f0b3b1","Improving the performance of the turnaround process using value operations methodology","Samsam, M.","Curran, R. (mentor)","2015","One of the daily operations that a civil airplane goes through is the turnaround of ground handling process or what commonly known as the turnaround process. By improving the performance of the turnaround process, there would be multiple benefits for the airlines and the airports, costs can be saved and more profit can be created due to higher useability of the aircraft. Also the punctuality of the airlines and the airports can be enhanced by decreasing the amount of delays caused by the turnaround process. According to Kenya Airways (KQ), in 2010-2011 the turnaround process is the second largest contributer to delays after network connectivity which accounts for about 28% of their total delays. This proves how significant the performance of the turnaround process might be to the airlines as well as to the airports. Most available literatures on the turnaround process focused on reducing the turnaround time, or improving its punctuality. The novelty of this MSc research is to determine a strategy that improves the performance of the turnaround process based on all its value drivers from the perspective of stakeholders. This has led to the formulation of the research question which is stated as follows: “How can a change in value be measured for relevant stakeholders within turnaround process when evaluating new ideas in improving its performance?” The methodology implemented in approaching this research and ultimately, answering the research question, is to develop a value model of the turnaround process based on value-focused thinking, specifically, value operations methodlogy (VOM). With this value model, the alternative strategies aiming at improving the performance of the turnaround process can be evaluated with respect to the current strategy. Eventually, the strategy that adds as much value for the relevant stakeholders can be determined. The turnarounds performed by KQ at Jomo Kenyatta International airport (JKIA) of Boeing 737-300 from January till June 2012, are used as practical case study in this research. From the results obtained from the calculations, It is recommended to implement lean production system within passengers boarding and disembark and to implement theory of constraints within catering and aircraft cabin cleaning.","turnaround process; value operations methodology; improvement techniques","en","master thesis","","","","","","","","","Aerospace Engineering","ATO","","Air Transport and Aerospace Operations","",""
"uuid:00a7777e-887a-4cdd-9479-a256840716d3","http://resolver.tudelft.nl/uuid:00a7777e-887a-4cdd-9479-a256840716d3","Improving the performance of the turnaround process using value operations methodology","Samsam, M.","Curran, R. (mentor)","2015","One of the daily operations that a civil airplane goes through is the turnaround of ground handling process or what commonly known as the turnaround process. By improving the performance of the turnaround process, there would be multiple benefits for the airlines and the airports, costs can be saved and more profit can be created due to higher useability of the aircraft. Also the punctuality of the airlines and the airports can be enhanced by decreasing the amount of delays caused by the turnaround process. According to Kenya Airways (KQ), in 2010-2011 the turnaround process is the second largest contributer to delays after network connectivity which accounts for about 28% of their total delays. This proves how significant the performance of the turnaround process might be to the airlines as well as to the airports. Most available literatures on the turnaround process focused on reducing the turnaround time, or improving its punctuality. The novelty of this MSc research is to determine a strategy that improves the performance of the turnaround process based on all its value drivers from the perspective of stakeholders. This has led to the formulation of the research question which is stated as follows: “How can a change in value be measured for relevant stakeholders within turnaround process when evaluating new ideas in improving its performance?” The methodology implemented in approaching this research and ultimately, answering the research question, is to develop a value model of the turnaround process based on value-focused thinking, specifically, value operations methodlogy (VOM). With this value model, the alternative strategies aiming at improving the performance of the turnaround process can be evaluated with respect to the current strategy. Eventually, the strategy that adds as much value for the relevant stakeholders can be determined. The turnarounds performed by KQ at Jomo Kenyatta International airport (JKIA) of Boeing 737-300 from January till June 2012, are used as practical case study in this research. From the results obtained from the calculations, It is recommended to implement lean production system within passengers boarding and disembark and to implement theory of constraints within catering and aircraft cabin cleaning.","turnaround process; value operations methodology; improvement techniques","en","master thesis","","","","","","","","","Aerospace Engineering","ATO","","Air Transport and Aerospace Operations","",""
"uuid:a97ad6e6-0d97-4e3c-a9d2-bd3c406e3299","http://resolver.tudelft.nl/uuid:a97ad6e6-0d97-4e3c-a9d2-bd3c406e3299","Improving the Outbound Logistics at KLM Engineering & Maintenance","Porozantzidou, S.","Janssen, M. (mentor); Ludema, M.W. (mentor); Lukszo, Z. (mentor); Kroes, B. (mentor)","2015","Within this report, a process improvement framework is developed and applied in the case of the outbound Logistics process at KLM Engineering & Maintenance. The methodology proposed for the improvement of the process includes a synergy of three different, but related theories: Lean, Six Sigma and Engineering Design. The integration of their critical steps are followed in order to develop improvement recommendations. These are to define the current state and the existing point, measure the process performance in terms of the predefined performance metrics making use of reliable data, develop and analyze improvement techniques. In the context of the analysis phase and due to certain limitations, a specific work scope has been chosen and an algorithmic approach has been applied in order to develop personnel's scheduling scenarios, test and evaluate them in terms of Turnaround Time, Quality and Cost. Next the improvement step includes the proposal of feasible solutions based on the analysis performed. Finally, the control phase helps the continuous improvement of the outbound Logistics through performance management tools","Process Improvement; Lean Six Sigma","en","master thesis","","","","","","","","","Technology, Policy and Management","Technology Policy Management","","Management of Technology","",""
"uuid:c5aaba1a-767f-414a-a19e-6194b0d81289","http://resolver.tudelft.nl/uuid:c5aaba1a-767f-414a-a19e-6194b0d81289","A Maturity Model for Maintenance Departments of Public Organisations: An adaptation of the EFQM model","Puspita Sari, F.","Hermans, M. (mentor); Straub, A. (mentor)","2015","The growing awareness of delivering public services into more costumer-oriented minded triggers the public organisations to manage their assets professionally. Building assets are one of the resources owned by the public organisations that need to be maintained. Maintenance departments are part of the public body that have responsibilities to make sure that the building assets are functioning well and can perform for what it is designed for. The problems arise when there are many buildings that should be managed within different functions and types; such as monumental buildings, schools, offices, etc. creates complexities. Furthermore, the nature of public organisations is different compared to private organisations. Public organisations must follow the law and regulations, facilitating stakeholders’ opinions and politics, and satisfying public. It is questioned whether the maintenance departments are capable to perform the maintenance activities professionally. In order to reveal the capabilities of an organisation a measurement tool is needed. One of the measurement tools that can disclose the professionalism of organisations is a maturity model. With maturity model, an organisation can understand their current maturity level and design their strategy to reach the next level. Furthermore, this is a self-assessment tool that is simple to use. A maturity model can consist of several levels of five, six, or seven, that will depend on the desired function. It is believed that the higher the level, the more professional is the organisation. Several quality management tools are being used by many organisations to enhance their professionalism, for instance the EFQM model. The EFQM model is commonly used in Europe that has components of “enablers” and “results”. By using those components, organisations can value their performances and processes. The main purpose of this research is to develop a maturity model that can measure the capabilities of maintenance departments. By having this tool that specifically designed for building maintenance departments, they can design strategies that fit their goals. Furthermore, to narrow down the research, the subjects of Planned preventive maintenance and Responsive maintenance are involved. To develop a maturity model as an adaptation of the EFQM model, there are several steps to do. Firstly, the literature reviews are conducted. The topics that have to be explored are the types of maturity models, the EFQM model, and the activities of maintenance departments include the Planned preventive maintenance and Responsive maintenance. There are two maturity models that become main references; the Capability Maturity Model (CMM) by Paulk et.al (1993) and the Public Commissioning Maturity Model (PCMM) by Hermans et.al (2014). The main important aspects of the maintenance departments are then summarised and linked to those maturity models and the EFQM enablers. The result is the proposed maturity model. Secondly, the first round interviews are conducted to get opinions and feedbacks from the experts about the proposed maturity model. This will find the relevancy of the key aspects in the model. The results of these interviews are the proposed maturity model and maturity levels. The third step in this research is to design an assessment sheet that can be used to measure the maturity level. This proposed assessment sheets are consisting of 26 questions with five multiple choices for each question. The fourth step is to carry on the second round interviews to explore whether the proposed assessment sheet is relevant to test maintenance departments. The results of the interviews improve the questions and the multiple answers, which are improving the maturity levels. Finally, as final products of this research, a maturity model for maintenance departments and an assessment sheet are formed. The final maturity model consists of five main aspects, 20 sub aspects, and five levels for every main aspects and sub aspects. The final assessment sheet is consisting of 27 questions with five multiple answers per question.","maturity model; EFQM; maintenance; building maintenance; asset management; quality improvement; public sector; public organisation; organisation management; performance measurement; maintenance department; maintenance organisation; construction","en","master thesis","","","","","","","","","Architecture and The Built Environment","Real Estate & Housing","","Design and Construction Management","",""
"uuid:330efcf5-aec0-4441-967e-a86b778e65a2","http://resolver.tudelft.nl/uuid:330efcf5-aec0-4441-967e-a86b778e65a2","Large Strain Analysis of Electro-Osmosis Consolidation for Clays","Yuan, J.","Hicks, M.A. (promotor)","2015","Consolidation of soft clay creates a lot of problems in foundation engineering, because of the very low clay permeability and high compressibility. Primary consolidation takes a long time to complete if the material is left consolidating under atmospheric evaporation, and traditional dewatering techniques, such as surcharge preloading, vacuum preloading or vertical drains, have been used for decades to shorten the consolidation time. Among new soft ground improvement technologies, electro-osmosis consolidation is receiving much attention as a possible time efficient solution. Electro-osmosis is a novel technique to consolidate soft clays, and involves the flow of pore fluid in a soil mass in response to an applied electrical field. The electrodes (positive and negative) are installed in pairs in the soil mass; the direct current then forces ions in the mobile part of the electric double layer (EDL) to move from the anode towards the cathode, causing water flow. Electro-osmosis is found to be more effective in clayey soils because the electro-osmosis permeability is independent of the grain size. This means that electroosmosis can generate flow rates that are 100 to 1000 times greater than hydraulic flows in fine grained soft clays. The purpose of this thesis is to develop a numerical model for simulating multidimensional and fully coupled multi-physics electro-osmosis consolidation, including the elasto-plastic behaviour of soil and time dependent transport parameters at large strain. Special attention is paid to the simulation of complicated geometries and boundary conditions, and to the inclusion of more advanced elasto-plastic constitutive models. The overall goal is to develop a more realistic numerical tool which addresses the main features of electro-osmosis consolidation, and that has potential use in the design and optimization of field applications. In this thesis, numerical models for the electro-osmosis consolidation of soft clays in multi-dimensional domains at large strain are presented, which consider the full coupling of the soil mechanical behaviour, pore water transport, pore gas transport and electric flow. In particular, elasto-plastic constitutive models (i.e. the Modified Cam Clay model and Barcelona Basic Model) are employed to describe the mechanical behaviour of the clay, and some empirical expressions are employed to describe the nonlinear transport parameters. The proposed models have been verified against analytical/numerical solutions and also evaluated with results obtained formlaboratory experiments. Overall, excellent agreement has been found, which demonstrates the accuracy and efficiency of the proposed models. Updated Lagrangian formulations are employed to account for the geometric nonlinearity. The importance of considering large strains in a consistent and proper way is demonstrated, and differences with models based on small strain theory are highlighted. As deformation is the key concern during consolidation behaviour, various numerical examples are investigated to study the deformation characteristics. The ratio of electro-osmosis permeability to hydraulic permeability keo/kw is a key factor in electro-osmosis consolidation. Generally, electro-osmosis permeability and hydraulic permeability decrease with a decrease in the void ratio and degree of water saturation, but the decrease in hydraulic conductivity is much faster than the decrease of electro-osmosis permeability, so the ratio keo/kw increases during the consolidation process. A field test of electro-osmosis consolidation has been analysed, showing excellent agreement between the computed and measured settlements. Various electrode configurations, as well as current intermittence and current reversal approaches for electro-osmosis consolidation have also been investigated using the proposed model. The particular contribution of this thesis is that it introduces a realistic numerical tool for the simulation of electro-osmosis consolidation. It is able to simulate field applications with complicated boundary and geometry conditions, as well as practical applications such as current intermittence and polarity reversal, which are often employed in the field to achieve efficient and economical consolidation. Feasibility studies and a proper design are important for the field application of electro-osmosis consolidation. Hence this numerical tool has potential use in the design and analysis of electro-osmosis consolidation, including the assessment of factors for achieving optimal dewatering effects and estimating the cost.","elasto-plastic; electro-osmosis consolidation; finite element analysis; ground improvement; large strain","en","doctoral thesis","","","","","","","","2016-05-12","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:809891f8-ebca-43fd-9996-76d33c2d1ee8","http://resolver.tudelft.nl/uuid:809891f8-ebca-43fd-9996-76d33c2d1ee8","Practical improvement of the growers’ transport operation in a demand-driven floricultural sector","Loenis, B.J.C.","Wiegmans, B. (mentor); Zuidwijk, R. (mentor); Van Lint, J.W.C. (mentor); Duinkerken, M. (mentor); Wiggenraad, P.B.L. (mentor); Timmerman, B. (mentor); Koppes, R. (mentor)","2015","This research investigates the changes which occur in the floricultural sector and how this changing sector affects the transport operation of floricultural growers. By means of demand forecasting and transport scenarios a practical and robust transport solution has been found for the growers.","floricultural sector; transport improvement","en","master thesis","","","","","","","","2020-07-02","Civil Engineering and Geosciences","Transport & Planning","","","",""
"uuid:f24bde6d-df7a-4694-bf57-08c5422966a0","http://resolver.tudelft.nl/uuid:f24bde6d-df7a-4694-bf57-08c5422966a0","Assessment of the consequences of higher safety standards for flood defences along rivers in The Netherlands","Van Zuijlen, J.J.","Kok, M. (mentor); Van Vuren, B.G. (mentor); Mosselman, E. (mentor); Kroekenstoel, D. (mentor)","2015","A large part of the flood defences in The Netherlands does not meet the present safety standards. In 2014 the delta programme has proposed new safety standards, which are based on the flood risk approach. These new safety standards will for a lot of river dikes be stricter than the currently prevailing safety standards. A lot of work has to be done to make sure all the river dikes will meet the new safety standards. The safety level of river dikes can be improved by means of spatial measures, which decrease the hydraulic load on the dikes by increasing the flood conveyance capacity, or by dike improvements, which increase the strength of the dike. The effectiveness of spatial measures has always been assessed in terms of water level reduction and not in terms of reduction of the flood probability. In this research a rapid assessment tool is developed with which the reduction of the flood probability by spatial measures can be assessed. This reduction has been calculated for several types of measures and it is compared with the effectiveness of more traditional dike improvements. The delta programme prescribes a strategy in which the increase of the flood probability because of climate change is counteracted with spatial measures. The difference between the current state of the dikes and the new safety standards should be resolved with dike improvements. This research shows that the flood probability reduction by spatial measures is overestimated. Due to this overestimation more spatial measures will be necessary to counteract climate change than was expected. A new strategy is proposed in which the flood probability for failure mechanism overflow/overtopping is reduced with a combination of dike improvements and spatial measures. The probability of failure for other failure mechanisms (piping, macro stability) is reduced with only dike improvements.","Room for the River; probability of flooding; spatial measures; dike improvements; effectiveness; river dikes; safety standards; delta programme","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","Hydraulic Engineering","",""
"uuid:d02725d6-a2ea-43d8-98a7-70d0ea2e7fe3","http://resolver.tudelft.nl/uuid:d02725d6-a2ea-43d8-98a7-70d0ea2e7fe3","Increasing the effectiveness of information distribution in data-driven organizations: Going back to the source: looking for improvement potential in the existing information related structuring at HEINEKEN Brewery Zoeterwoude","De Regt, E.F.G.","Herder, P.M. (mentor); De Haan, A.R.C. (mentor); De Bruijne, M.L.C. (mentor); Schrama, I.J. (mentor)","2015","In today’s information driven-economy, the key for manufacturing organizations like HEINEKEN Brewery Zoeterwoude to become and remain competitive lies in their capacity to acquire sound, relevant and timely information, as well as in ability to learn from the acquired information. The latter is believed to be linked to the extent in which the information is created and distributed in a structured way. In this research a progressive case-study is conducted as to assess the improvement potential that lies in the current structuring mechanisms that are in place.","Information distribution; Organizational structuring; Performance Improvement Methodologies; Case study","en","master thesis","","","","","","","","","Technology, Policy and Management","Energy & Industry","","Systems Engineering, Policy Analysis and Management","",""
"uuid:c2e74325-30f8-4bf6-8a76-9cc2f044be8a","http://resolver.tudelft.nl/uuid:c2e74325-30f8-4bf6-8a76-9cc2f044be8a","Efficient global robust optimization of unconstrained problems affected by parametric uncertainties","ur Rehman, S.; Langelaar, M.","","2015","A novel technique for efficient global robust optimization of problems affected by parametric uncertainties is proposed. The method is especially relevant to problems that are based on expensive computer simulations. The globally robust optimal design is obtained by searching for the best worst-case cost, which involves a nested min-max optimization problem. In order to reduce the number of expensive function evaluations, we fit response surfaces using Kriging and use adapted versions of expected improvement to direct the search for the robust optimum. The numerical performance of the algorithm is compared against other techniques for min-max optimization on established test problems. The proposed approach exhibits reliable convergence, is more efficient than previous methods and shows strong scalability.","kriging; min-max optimization; expected improvement; robust optimization; parametric uncertainties; worst-case design","en","journal article","Springer","","","","","","","","Mechanical, Maritime and Materials Engineering","Precision and Microsystems Engineering","","","",""
"uuid:40f65e31-0c38-4b59-95b9-20c64e908b93","http://resolver.tudelft.nl/uuid:40f65e31-0c38-4b59-95b9-20c64e908b93","Containing urban sprawl: An integrated improvement of space-tranport strategies to reduce air pollution emission","Ambarwati, L.; Verhaeghe, R.J.; Pel, A.J.; van Arem, B.","","2014","Diverse effective strategies have been designed to minimize the phenomenon of urban sprawl. Previous research focused on the link between spatial and transport development strategies to achieve this goal, with the intention of increasing mobility, reducing commuting time and travel costs. However, a side effect of urban sprawl is an increase of air pollution. Higher pollution levels result in higher costs for road users. To reduce these costs, improvement in public transport linked to urban development is an essential factor in limiting air pollution emission. Current research is insufficient to demonstrate the effects of urban sprawl on air pollution emission. This paper examines the extent to which an integrated approach to space-transport development strategies is able to reduce air pollution emission. The analysis includes the effect of different improvement of public transport (PT) and spatial alternatives on the load of air pollution A pro-active approach is applied for a potential viable up to 2030. By examining the alternative strategies, the intention is to reduce travel costs together with decreasing the load of air pollution emission. This research proposes the improvement of public transport (PT) by planning a combination of Mass Rapid Transit ((MRT), Light Rapid Transit, Bus rapid Transit and feeder systems. In addition, a structure of compact zones is designed as urban spatial strategy alternatives. The conclusions indicate that firstly, the improvement of PT (a combination of Mass Rapid Transit (MRT), Light Rapid Transit, Bus rapid Transit and feeder systems) has an effect on the reduction of air pollution load compared to the current PT situation (minibuses and buses). Secondly, the spatial planning with compact zone does not show a significant decrease in determining the load of air pollution. Its substantially reduction is achieved with the design of improvement of PT systems. The best option for reducing commuting costs and air pollution, the implementation of the improvement of PT systems alternative, is then recommended.","Space-transport development; Controlling urban sprawl; Air pollution emission; Ratio employment and population; Improvement of public transport; Settlement development","en","conference paper","Institute of Research Engineers and Doctors","","","","","","","","Civil Engineering and Geosciences","Transport and Planning","","","",""
"uuid:0f2795be-ab6d-46f3-8324-6cd9997b7ac2","http://resolver.tudelft.nl/uuid:0f2795be-ab6d-46f3-8324-6cd9997b7ac2","Smart Operation of Gas Turbine Combined Cycle Plants: Prediction and Improvement of Thermal Efficiency at Part Load","Boksteen, S.Z.","Van Buijtenen, J.P. (promotor)","2014","This thesis investigates various operational aspects of Gas Turbine Combined Cycle Power Plants (GTCC). GTCC power plants are expected to play an increasingly important role in the balancing of supply and demand in the electricity grid. Although originally meant for predominantly base load operation with high efficiencies, market circumstances, namely the increasing supply of unpredictable wind and solar power, force these units to be operated frequently across a wide range of load settings. The required flexibility opens a need for models, that can predict the plant performance accurately at design point as well as off-design conditions. The models and performance data, made available by equipment manufacturers, are usually too general to be applied for accurate prediction and optimization purposes. Adding to this, the electricity producing companies usually do not possess detailed design information, so that creating accurate process models presents an extra challenge. The chapters of this thesis are dedicated to the proposal of several methods for overcoming challenges related to the operation of existing gas turbine combined cycle plants in current and future energy markets. All models and procedures developed in the framework of this thesis, are applied to the Alstom KA-26-1 GTCC as a case study. Two of these units were installed at the Maxima Power Station in Lelystad for GDF SUEZ Energy The Netherlands. The current study is first placed in the broader context of the developments in the electricity market, and of research fields related to this subject. The importance of accurate simulation tools is motivated, and the potential role of uncertainty management and optimization is put forward. The implications of the market developments are synthesized into a concise problem statement. The productive core of GTCC plants is the gas turbine, especially when there is no external firing in the steam cycle. A step wise method for accurately modeling the design and off-design steady state performance of gas turbines is presented. Tuning performance models to measured data typically available to an engine user is an important task. Therefore, a method for achieving this is proposed and applied to a case study: the GT26, an industrial gas turbine (part of the KA-26 plant) with two sequential combustor components. The results of this modeling effort indicate that the accuracy decreases towards part load. Thermodynamic modeling of the steam cycle, although a widely practiced discipline, still presents some challenges in case of industrial-size units. Second-law analysis is often added to thermodynamic flow sheet calculations; this can be enhanced by analyzing the interaction between plant components with the help of a novel procedure presented in the thesis. For this purpose, the plant model is calculated over a randomly and uniformly distributed set of input conditions, calculating the (second law) thermodynamic losses of major components for every case. (The term numerical experiment is used for this procedure.) After this, the resulting data is processed and visualized to reveal expected as well as unexpected mutual relations between the losses of individual plant components. When gas turbine and steam cycle models, and computer models in general, are applied to make predictions, and economical decisions are based on these models, there is always an amount of uncertainty present with respect to the validity of the predictions. Quantification and reduction of this uncertainty can be of significant value for stakeholders. In this context, an existing method for statistical analysis and calibration of computer models, the Kennedy & O'Hagan framework, is applied to the the previously presented gas turbine and steam cycle models. The purpose is to enhance the accuracy of (especially) part load efficiency prediction by calibrating the models with the available (industrial) measurements. The mathematical tools applied in this framework are explained, along with the manner in which it is applied to the gas turbine and steam cycle models respectively. For plant performance prediction, it is necessary to integrate the models, so that uncertainties in one model are propagated through the next. Two methods are described for achieving this: integration of the models can be done either before or after calibration. The two stochastic integration methods are applied to predict the efficiency of the case study plant. While both methods produce accurate results, there is an indication that integration after calibration is slightly more accurate. The most important objective for the current study, besides accurate performance prediction, is the proposal of efficiency optimization methods. The final part of the thesis illustrates methods for analyzing efficiency improvement possibilities of existing (gas turbine combined cycle) power plants, and optimizing part load efficiency with steady state plant models. Firstly, the data from the numerical experiment mentioned earlier are processed. By comparing how strong the exergy losses in major components are correlated to overall thermal efficiency of the plant, the low pressure steam turbine is shown to be the component whose thermodynamic losses have the largest effect on the variations in overall plant efficiency. However, it is also known that gas turbine losses represent the largest exergy loss. This seeming contradiction is thoroughly explained in the thesis. By using a clustering algorithm, operational regimes are revealed with respect to the losses in the low pressure steam turbine and gas turbine. Efficiency optimization is performed at ambient conditions corresponding to these distinct operational regimes. The results of optimization indicate that the optimum set of operational settings is different for each of the identified regimes, thereby confirming that they are distinct regimes. After using deterministic models for the efficiency maximization, model uncertainty is incorporated in the calculations, and the stochastic models presented earlier are applied. The difference with the previous optimizations is that in this case, the applied model has been proven to give more accurate results, and it provides the statistical distribution and expected value of the plant efficiency, not just a deterministic value. The results of optimization under uncertainty are compared to results of deterministic optimization under equal ambient conditions: the resulting optimal operational settings for both cases are shown to be similar in many aspects; differences are analyzed and put into perspective. The final part of the thesis synthesizes the main conclusions and recommendations from the previous sub-studies and places them in the general context of the research field. Suggestions are proposed for possible applications of the proposed methodologies to problems which are outside the scope of the thesis.","part load operation; efficiency improvement; Gas Turbine Combined Cycle; uncertainty management; Bayesian calibration; exergy analysis","en","doctoral thesis","","","","","","","","","Mechanical, Maritime and Materials Engineering","Process & Energy","","","",""
"uuid:5b0f0986-cdfc-46e7-9238-2748f07c83cf","http://resolver.tudelft.nl/uuid:5b0f0986-cdfc-46e7-9238-2748f07c83cf","Improving Operational Efficiency of Discrete Production Processes in Large Manufacturing Organizations","Vijfhuizen, F.W.","Tavasszy, L. (mentor); Van Duin, R. (mentor); Van der Voort, H. (mentor); Derksen, T. (mentor); Winter, B. (mentor)","2014","In the present time large manufacturing organizations operate on a global scale and thereby form an extremely competitive market. Far going globalization makes markets highly competitive, putting the pressure on these organizations to be more innovative and improve the efficiency of its production processes in order to lower overall costs. These goals are aimed to be achieved by introducing elaborate continuous improvement strategies. Implementing such strategies however has far going implications on organizations, in terms of performance management, working culture, and organizational structure. Companies have often implemented one or more continuous improvement strategies. While these strategies promise to result in a perfect process, in practice this is not the case. Problems form when there is a significant gap between company goals and the actual operational performance. In that case a situation arises where not ideal operational performance can be caused by logistical malfunctions, a continuous improvement strategy that is not performing optimal, friction in the organizational structure, or even a combination of all. It is therefore difficult for organizations to identify what causes a non-optimal operational performance, given the complexity of the described environment. The objective of this research is to improve this operational performance by overcoming this knowledge gap. The following general research question is formulated to overcome this knowledge gap: How can large manufacturing companies identify causes of discrete production processes not performing in line with company goals? In this research a three step approach is used. The first step is to zoom out from the logistic process and analyze the characteristics of the organization and the used continuous improvement strategy. By comparing the organizational characteristics with academic literature, strengths and weaknesses of the organization can be identified, and also the corresponding opportunities and threats. The used continuous improvement strategy is analyzed, for it is never flawless. Methodologies keep evolving and improving, and new theories are being developed and tested every day. Looking critical at the used improvement strategy will provide insight in missed opportunities and the importance of certain focal points in the organization. The second step is linking these findings to an analysis of the logistical process. It is important to determine how the operational efficiency is defined and how it is measured. Step one might provide a different perspective for analysis or focal points. In this second step improvement projects can be selected and defined on an operational level. Step three consists of performing the selected improvement projects. It is important to incorporate the findings of step one into these projects. This way the findings in academic theory can be evaluated by testing in practice. This evaluation provides concrete feedback on the found causes of non-optimal performance of the production line. Combining these three steps will provide (i) a thorough analysis of the organization, (ii) identifications of barriers and enablers in the organization, and (iii) will present opportunities to improve the operational efficiency beyond the knowledge that is present in the organization. With the gained knowledge, step one can be repeated in order to create an iterative process for continuous improvement. This approach is conducted and tested at the Heineken brewery in Zoeterwoude, the Netherlands. During a six month period, a real life case study is performed at production line 81, a bottling line that packs beer into cases for export. First it is shown that it is important to take into account the different perspectives between management and operators. In order to improve the production line in a structural way it is essential to communicate with operators in such a way it aligns with their goals. Next to this it is found that there are opportunities in using the tools presented in the Theory of Constraints. Based on a bottleneck analysis, it is shown that the losses with the biggest impact on the total production line are found downstream of the designed bottleneck, signaling a hidden bottleneck. It is shown that the output performance can be significantly improved by diminishing the amount of breakdown in the machines downstream of this hidden bottleneck. The performance indicator “Operational Performance Indicator No Order No Activity” has increased with 6.34 percentage points and the deviation of this indicator has diminished with 1.63 percentage points. If this major increase can be maintained in the future, this improvement could save the organization 115,402 on a yearly basis in non-cash savings. This shows that using the Continuous Improvement strategy Total Productive Management is an effective tool for Heineken to structure its continuous improvement efforts. The foremost general recommendation in respect to strengthening the findings in this research is performing more similar case studies. A case study at a comparable manufacturing organization is necessary to compare results and draw conclusions on the extent to which the findings can be generalized. The expectation is that the found principal-agent dynamic at Heineken is strongly comparable to other large manufacturing organizations. If that is the case, this can be a highly interesting addition to the theory on organizational structures. For Heineken from a logistical point of view it is important to keep working on the newly identified bottlenecks, the Packer and Multipacker machines. Every minute won on these machines can directly benefit the operational efficiency of the entire line. These findings can also be applied at the other production lines in the brewery as well. This horizontal expansion can provide new insights into the general mechanisms of the entire brewery. For the long term it is recommended to involve the proposed rule of thumb in the monthly meeting between a rayon manager and the installation manager. Last, if Heineken wants to cope with the found principal-agent dilemma, a thorough behavioral change is required in the entire organization. It is recommended to implement a form of change management, for example the methodology founded by Kotter (1996).","Continuous Improvement; Total Productive Management; Theory of Constraints; Large Manufacturing Organizations; Real Life Case Study","en","master thesis","","","","","","","","2019-10-09","Technology, Policy and Management","Transport and Logistics","","Systems Engineering, Policy Analysis and Management","",""
"uuid:e6a3d9e9-0991-4a8e-b774-d3e2135b168c","http://resolver.tudelft.nl/uuid:e6a3d9e9-0991-4a8e-b774-d3e2135b168c","Processing Analysis & Market Analysis on Company X Bentonite","Van der Waal, K.T.","Van Paassen, L.A. (mentor); Benndorf, J. (mentor)","2014","Bentonite is a clay that is used in many industrial applications. Company X required an investigation on the bentonite that is mined by Company Y. Currently Company X produces cat litter only from her bentonite, but other applications might be of economical interest to the company. After scoping down to 4 applications other than cat litter (drilling mud, foundry sand, soil improvement and bleaching earth), the possibility of processing bentonite to gain the physical properties required by these 4 applications was investigated. The information needed for this investigation is mostly gathered from scientific reports based on the processing of Country A bentonites. From the results from earlier researches on Country A bentonites it is concluded that Country A bentonites can be made suitable for all 4 applications through several processing steps. The second part of the report focuses on the market possibilities of the 5 applications (the cat litter application included). It is found that the bleaching earth and the drilling mud market are most likely to be fit for a market entry. It is also concluded that the bleaching earth application is of most economical interest when looked at the net present value of the investment after 15 years. The drilling mud application is of most economical interest when looked at the internal rate of investment. The soil improvement application requires almost no change in processing steps when compared to the production of cat litter and might therefore be of economical interest to Company X. There is a risk of turning up with a negative net present value (after 15 years) when Company X would choose to invest in the drilling mud, foundry sand and bleaching earth application. Therefore the final conclusion is that Company X should do a deeper investigation in the soil improvement application, since it is found that the economic potential is very high for this application. When this seems to be an unrealistic or economical uninteresting investment, Company X should investigate a further expansion of cat litter export.","Bentonite; characterisation; drilling fluid; foundry sand; soil improvement; bleaching earth; processing analysis; market analysis","en","bachelor thesis","","","","","","","","2019-10-09","Civil Engineering and Geosciences","Geoscience & Engineering","","Resource Engineering","",""
"uuid:27b19aa0-979e-4e99-9f53-cbc852a09981","http://resolver.tudelft.nl/uuid:27b19aa0-979e-4e99-9f53-cbc852a09981","Pricing via functional size: A case study of 77 outsourced projects","Huijgens, H.; Gousios, G.; Van Deursen, A.","","2014","A medium-sized west-European telecom company experienced a worsening trend in performance, indicating that the organization did not learn from history, in combination with much time and energy spent on preparation and review of project proposals. In order to create more transparency in the supplier proposal process a pilot was started on Functional Size Measurement pricing (FSM-pricing). In this paper we evaluate the implementation of FSM-pricing in the software engineering domain of the company, as an instrument useful in the context of software management and supplier proposal pricing. We found that a statistical, empirical, evidence-based pricing approach for software engineering, as a single instrument (without a connection with expert judgment), can be used in distributed environments to create cost transparency and performance management of software project portfolios","Software Economics; Software Pricing; Functional Size Measurement; FSM-pricing; Continuous Improvement","en","report","Delft University of Technology, Software Engineering Research Group","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Software Technology","","","",""
"uuid:64e7724c-a053-4ba1-b926-aab9e0ea6ba2","http://resolver.tudelft.nl/uuid:64e7724c-a053-4ba1-b926-aab9e0ea6ba2","Design guidelines and empirical evaluation tools for inland ships","Rotteveel, E.; Hekkenberg, R.G.; Liu, J.","","2014","For inland ships, state-of-the-art hull form design is to a large extent based on experience, common sense, or adjusting previous designs. The idea therefore arises that further optimization is possible if the right knowledge is available. This knowledge is insufficiently available due to two main reasons. First, research into inland ship optimization is usually omitted from the design process due to the high cost compared to the design budget. This has led to a lack of fundamental knowledge about the complex hydrodynamics around the hull of an inland ship. Second, as a consequence of omitting optimization research, adequate empirical power prediction methods have not been developed for inland ships due to the lack of data. In the Top Ships project, effort is put in the development of an empirical method for inland ship power estimation as well as the derivation of design guidelines. Both should aid designers in the process of a new ship's design. The present paper gives an overview of available information from literature that aids to design of inland ships. Design guidelines and power prediction methods that relate to the design of a new inland ship are presented and discussed. The conclusions emerging from this review lead to the choice of focus in the Top Ships project. Therefore an introduction, the approach and intended results of this project are briefly presented as well.","inland ships; literature review; shallow water; ship resistance; inland ship improvements","en","conference paper","Budapest University of Technology and Economics","","","","","","","","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","","","",""
"uuid:20aeb081-0dfc-42fc-a31e-ce1dddc41804","http://resolver.tudelft.nl/uuid:20aeb081-0dfc-42fc-a31e-ce1dddc41804","Characterisation and applications of bentonite","Ooms, M.C.","Van Paassen, L.A. (mentor); Benndorf, J. (mentor)","2014","A research was undertaken to find the suitability of Turkish calcium bentonite from the mines of a Company. Four samples of bentonite mines in the {\""U}nye region are researched, the M1, M2, M3 and M4 mine. The suitability of drilling fluid, foundry sand, soil improvement and bleaching earth applications is found through research on the characteristics of bentonite and by testing the specifications of the chosen applications. In this research the following bentonite characteristics are determined: cation exchange capacity, chemical composition, free swelling capacity, liquid limit, methylene blue adsorption, moisture content, pH, plastic viscosity, specific surface, swelling index and yield point. Characteristics are tested according the associated methods of the specifications. For drilling fluid, the API 13A and OCMA Standard is used. The IS 12446:2007 by the Bureau of Indian Standard is used for foundry sand. For the applications of soil improvement and bleaching earth international standards cannot be found. For this reason a specification of the European Commission on soil improvement is used. Recommended ranges found in literature are used in testing the suitability of bentonite for bleaching earth. The results of this research show a suitable outcome for the use of drilling fluid. The M1 and M4 sample are API qualified and the M3 sample is conform the OCMA Standard. For foundry sand the bentonite samples are not suitable, all samples are not performing good enough on water absorption and cation exchange. Due to found traces of lead contamination in the M1, M3 and M4 bentonite samples, but these samples are still suitable in soil improvement according to the specifications of the European Commission. However, in the M2 sample there is no trace found of any heavy metal contamination and is, except the low nutrient content, suitable for soil improvement. All samples are very close to the recommended ranges found in literature for bleaching earth, therefore all samples are suitable for the application.","Bentonite; Characterisation; Drilling Fluid; Foundry Sand; Soil Improvement; Bleaching Earth","en","bachelor thesis","","","","","","","","2019-06-24","Civil Engineering and Geosciences","Geoscience & Engineering","","Geo-engineering","",""
"uuid:2c7e4e45-a38d-4f69-817e-6367d953a662","http://resolver.tudelft.nl/uuid:2c7e4e45-a38d-4f69-817e-6367d953a662","Improving Oasis Beach: Creating a sustainable and attractive beach around hotel Oasis in Varadero Cuba","Vrolijk, E.F.; Poelhekke, L.; Schlepers, M.H.; De Boer, G.G.","","2014","In the North of Cuba, the Oasis beach area is situated. The beach suffers from structural erosion and earlier measures to deal with this have not succeeded. In this project, a solution is offered to reach two goals: foremost, a beach improvement to the Oasis beach sector and second, a halt to the structural erosion in the sector in order to maintain the beach improvement. These goals are strongly linked to one another and contain several research questions to be able to find suitable solutions. A vast analysis on the area has been made. It becomes clear in the project that these impacts are decisive in the erosion that takes place, as natural beach recovery is limitedly possible. An important finding during the analysis is that there is no significant sediment transport in the Oasis beach sector during normal conditions. However, the steep bathymetry and the re-occurrence of cold fronts and hurricanes induce large cross-shore transport and sediment is extracted from the system, leaving the Oasis beach sector with a structural erosion problem. The solution of the problem would have to be a combination of hard and soft measurements. Three alternatives were created, plus a base alternative. The base alternative consists of the demolition of the existing structures and a nourishment. The three alternatives are respectively a ‘Perched beach’, ‘Emerged breakwaters’ and ‘Wooden L-shaped piers’. All alternatives were simulated with the use of Delft3D and XBeach. A Multi Criteria Analysis (MCA) was carried out to evaluate the alternatives. The most important criteria in this are the protection against erosion and spatial quality. The MCA, in combination with the estimated accompanying costs, resulted in a final solution proposal, being the perched beach. Although scoring high in general, a few adjustments are made to the design. An addition is made by introducing a sill to the alternative. The sill will take over the function of supporting the beach and enables a smaller beach nourishment and a better controllable beach profile, as it is build closer to shore. Furthermore, the height of the breakwater is increased in order to decrease the amount of necessary maintenance. The proposition of the solution comes with an indication of planning and costs. The construction time is estimated to be 343 days. Construction costs are calculated to be $ 6,970,175.70 CUP, including the costs for the initial nourishment and the demolition of existing structures.","beach improvement; Cuba; Delft3D; XBeach; nourishment","en","student report","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:f3ac1df2-81ca-470e-a17e-0edb4d42e122","http://resolver.tudelft.nl/uuid:f3ac1df2-81ca-470e-a17e-0edb4d42e122","Towards the introduction of fit-for-purpose project management: An explorative case study on implementing central planning and risk log","Teerlink, T.","Verbraeck, A. (mentor); Mooi, H.G. (mentor); Bosch-rekveldt, M.G.C. (mentor); Janssen, R. (mentor); Leenheer, D. (mentor)","2013","","Central Planning; Enterprise resource planning; Improvement program; Key Performance Indicators; Project Execution; Project Management; Risk Log; Work Break-down Structure","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","Construction Management and Engineering","",""
"uuid:e7866a4a-62fe-4a6f-bb22-2e4c53082be3","http://resolver.tudelft.nl/uuid:e7866a4a-62fe-4a6f-bb22-2e4c53082be3","Project Scheduling: The Impact of Instance Structure on Heuristic Performance","De Nijs, F.","Klos, T.B. (mentor)","2013","Many meta-heuristic approaches have been suggested for or applied to the Resource Constrained Project Scheduling Problem (RCPSP). The existence of a number of highly accessible standard benchmark sets has promoted a research focus on finding anything that improves average solution quality, without investigating what effect is responsible for the improvement, or what is responsible for holding us back. This work focuses instead on understanding the original constructive Schedule Generation heuristics and their interaction with a well known but poorly understood post-processing step called Forward-Backward Improvement that is known to almost always improve any generated RCPSP schedule. We follow an empirical investigation methodology by first observing the effect of FBI on a large generated testset. Based on these observations we explain why FBI works by means of hypotheses on its operation. These hypotheses generate predictions that we subsequently successfully test in a second round of experiments. In the process we are able to propose a novel priority rule heuristic based on the principles of FBI. We find that this new rule outperforms the current best priority rule heuristic.","Resource Constrained Project Scheduling; Priority Rule Heuristics; Forward-Backward Improvement","en","master thesis","","","","","","","","2013-11-12","Electrical Engineering, Mathematics and Computer Science","Software Technology","","Algorithmics","",""
"uuid:2f1d9ae2-7e26-4ac7-97ba-3cd9a185b33d","http://resolver.tudelft.nl/uuid:2f1d9ae2-7e26-4ac7-97ba-3cd9a185b33d","Sustainability Maturity Model: The Pilot Sustainability Agenda-Setting in Business","Wortel, M.C.","Korevaar, G. (mentor); Quist, J.N. (mentor)","2013","The Master’s programme Industrial Ecology is jointly organised by Leiden University and Delft University of Technology. Sustainable development is a young, developing field in which many standards, certificates, and initiatives are spawning. Companies are expected to work on sustainable development by its customers, investors, and society in general. It can be difficult to do this effectively because the field is cluttered and can be confusing. The Sustainability Maturity Model (SMM) presents an overview of sustainability topics and helps companies prioritise between them. The SMM was developed in a collaboration of Ecomatters (a consultancy firm in sustainability and regulatory affairs) and the master programme Industrial Ecology of Delft University of Technology and Leiden University to assist companies with defining their internal sustainability agenda. The SMM does that by supporting companies through providing an overview of the sustainability topics they are expected to manage, and prioritising them. The SMM consists of a list of 29 sustainability topics based on established standards, and is combined with a 5-step level system, that is based on the Capability Maturity Model. This project was commissioned by Ecomatters and its main goal was to operationalise the SMM and execute a pilot with potential users to assess the SMM’s viability as a consultancy product. The second goal was to relate the SMM to current academic literature. The SMM relates to current academic literature. It is based on the Triple Bottom Line (TBL) of ‘People, Planet, Profit’ developed by John Elkington. The TBL is the most widely accepted approach to sustainable development (Stubbs and Cocklin 2008). Sustainable development was defined by the World Council on Environment and Development as meeting the needs of the present without compromising the needs of future generations (WCED 1987). The topic list of the SMM is based on established frameworks: the European Eco-Management and Audit Scheme, the Dow Jones Sustainability Index, ISO 26000 on Social Responsibility, and Social Accountability’s SA8000. Next to topics from these frameworks, the SMM includes the topic Future Business Activities which is based on the widely used framework Transition Management that was developed to incorporate sustainability trends into the business strategy (Loorbach, van Bakel et al. 2010). The topic ‘Sustainability Awareness’ was added because it is recognised as an important factor for the sustainability performance of a company (McEwen and Schmidt 2007). Since the issues companies “are expected to manage” is an important theme in the SMM, it is important to understand the role business is expected to assume in sustainable development. Business is expected to address sustainability issues through developing sustainable products and processes (Hall, Daneke et al. 2010, Porter and Kramer 2011). Sustainable products and processes are expected to play an important role, but the issues in sustainable development are too complex to be tackled by single organisations (Loorbach, van Bakel et al. 2010). Therefore, business needs to form coalitions with different types of organisations (SustainAbility 2004). The level system of the SMM includes requirements regarding both expectations. The lower levels have to do with the internal processes and the highest level covers collaboration with other organisations. The levels are based on the Capability Maturity Model (Paulk, Curtis et al. 1993) that originated from software development and is now widely used as a basis for managing business processes in a stepwise approach (de Bruin, Rosemann et al. 2005). The level system follows the best practices for maturity models defined by De Bruin et al. (2005). The SMM does not present any final score on sustainability. For individual actors such as companies, ‘being sustainable’ is not possible since sustainability is a property of a system, not of an individual component (Nikolic 2009). The SMM does not prescribe a minimum level anywhere. Individual actors cannot be obliged to not perform unsustainable actions when they intend no harm and when the influence of those actions is too small to change anything (Sinnott-Armstrong 2010). Instead, companies are encouraged to define their own priorities and decide how strongly they want to perform on each individual topic. The SMM was reviewed in four steps: aligning the topics from the different standards, supplementing the topic list with findings from academic literature, fitting the level system to the CMM and the situation, and testing its operationalisation in a pilot. After the review, the SMM was operationalised by creating a leaflet that introduces potential participants to the pilot, an one-page introduction to the workshop, a presentation to guide the workshop, a set of forms to guide the consultant through the workshop and make quick notes on, and a format for the feedback report the companies received after the pilot. Eight companies in the chemical, food and energy industries with revenues of 176 million to 3,7 billion participated in the pilot. They were represented by one or two of their managers in sustainability (six companies) or communications (two companies). During the 3-hour workshops, the topics in the Sustainability Maturity Model were discussed one by one. After the workshops had been held, the participants received feedback reports that analysed their results as well as the average results of the entire group. The gap analysis and recommendations about topics to work on formed the core of these reports. The participants were phoned to discuss the value of this feedback and how it could be used within the company. From the perspective of the participants, the workshops and feedback reports were useful. The participants appreciated the broadness of the topics list, the structured approach, the face to face interaction, and the emphasis on prioritising. Applying the same management framework to each topic and being selective about the topics to work on was seen as a novel approach. Most of the participants felt that their feedback report provided useful input for determining the focus of their strategy. The SMM was tested with medium and larger sized companies and found suitable when the participants were open to the approach. According to an industry expert, it could be useful for smaller companies as well. The usefulness of the model depends on how open the company is to its approach of prioritising and advancing within a topic list. Even though literature research and the reactions from the participants show that the SMM is suitable for its intended use, several practical improvements could increase the usefulness of the SMM process further, the main recommendations being: conducting the workshop with multiple people to increase data quality, preparing them for the workshop better to save time during the workshop, and providing more detail on the requirements per topic in the feedback so it is easier for participants to define follow up actions. By doing workshops with a large group of similar companies the benchmarking function of the SMM can be improved, which is a feature the participants of the pilot asked for. Before this project, the concept of the SMM was defined, but it was not ready for use in a consultancy context yet. This project has strengthened the link between the SMM and current literature on sustainable development in the business context, has made the SMM usable, and the first pilot was conducted. The pilot was the first presentation of the SMM to potential users, and their predominantly positive reactions have shown that the SMM is now ready for use in a consultancy context. The SMM and the work done for it during this project are property of Ecomatters. This report contains the part of the information that was selected to be publicly available. Company results have been aggregated and anonymised, and parts of the analysis and description of the model have been omitted in this report to guarantee the confidentiality of this information. Parts of the analysis and description of the model were retained to serve as examples of the further development of the SMM and the results of that process.","sustainability; sustainable; agenda; priority; business; pilot; model; consultancy; manage; ISO 14001; SA 8000; Capability Maturity Model; company; EMAS; DJSI; ISO 26000; standard; guideline; people; planet; profit; GRI; topic; level; operationalise; organisational capability; management; maturity; capability; improvement; test; interview; feedback; workshop; benchmark; comparison; ambition; supply chain; life cycle; strategy; business strategy; partnership; collaboration; triple bottom line; prioritise; compare; collaborate; consult; consultant; companies; businesses; improve; capable; mature","en","master thesis","","","","","","","Campus only","","Technology, Policy and Management","Energy & Industry","","Industrial Ecology","",""
"uuid:b5abb48e-963c-4599-b737-b3b7a4a0874f","http://resolver.tudelft.nl/uuid:b5abb48e-963c-4599-b737-b3b7a4a0874f","Designing New Handling and Sorting Equipment","Thissen, J.J.","Prins, J.F. (mentor); Kooijman, A. (mentor); Vos, M. (mentor)","2013","The design of new handling and sorting equipment, together with the corresponding procedure. The equipment is designed for the (soda-) can industry. It has besides ergonomic advantages for the employees also quality improvements.","consistency of quality; ergonomically improvements; separator sheet sortation","en","master thesis","","","","","","","Campus only","2014-08-28","Industrial Design Engineering","Design Engineering","","Master of Science Integrated Product Design","",""
"uuid:671588d6-bafb-4363-9085-058d1844fb0e","http://resolver.tudelft.nl/uuid:671588d6-bafb-4363-9085-058d1844fb0e","A Strategic Case","Van Aken, N.","Buijs, J.A. (mentor); Bakker-Wu, S. (mentor); Gefken, W. (mentor); Noriega, D. (mentor)","2013","This graduation project is performed at Kofferfabriek Gefken, a small company that designs, produces and sells tailormade cases. More or less starting from scratch, a thorough internal and external analysis was performed, as well as two constructive sessions with the management. A new mission statement was formulated, and by using SWOT techniques and Brand-driven Innovation theory ( Roscam-Abbing, E.), a tactical improvement plan was developed. Concluding with a concrete product as an example of the wanted results, this thesis is a solid foundation for future developments inside Kofferfabriek Gefken.","Innovation; Tactical Improvement Plan; Strategy; Design","en","master thesis","","","","","","","Campus only","2014-03-27","Industrial Design Engineering","Product Innovation Management","","Master of Science Strategic Product Design","",""
"uuid:1b1c2e9a-2c6e-4aa2-815c-cdff3440851c","http://resolver.tudelft.nl/uuid:1b1c2e9a-2c6e-4aa2-815c-cdff3440851c","Biogeochemical processes and geotechnical applications: Progress, opportunities and challenges","De Jong, J.T.; Soga, K.S.; Kavazanjian, E.; Burns, S.; Van Paassen, L.A.; Al Quabany, A.; Aydilek, A.; Bang, S.S.; Burbank, M.; Caslake, L.F.; Chen, C.Y.; Cheng, X.; Chu, J.; Ciurli, S.; Esnault-Filet, A.; Fauriel, S.; Hamdan, N.; Hata, T.; Inagaki, Y.; Jefferis, S.; Kuo, M.; Laloui, L.; Larrahondo, J.; Manning, D.A.C.; Martinez, B.; Montoya, B.M.; Nelson, D.C.; Palomino, A.; Renforth, P.; Santamarina, J.C.; Seagren, E.A.; Tanyu, B.; Tsesarsky, M.; Weaver, T.","","2013","Consideration of soil as a living ecosystem offers the potential for innovative and sustainable solutions to geotechnical problems. This is a new paradigm for many in geotechnical engineering. Realising the potential of this paradigm requires a multidisciplinary approach that embraces biology and geochemistry to develop techniques for beneficial ground modification. This paper assesses the progress, opportunities, and challenges in this emerging field. Biomediated geochemical processes, which consist of a geochemical reaction regulated by subsurface microbiology, currently being explored include mineral precipitation, gas generation, biofilm formation and biopolymer generation. For each of these processes, subsurface microbial processes are employed to create an environment conducive to the desired geochemical reactions among the minerals, organic matter, pore fluids, and gases that constitute soil. Geotechnical applications currently being explored include cementation of sands to enhance bearing capacity and liquefaction resistance, sequestration of carbon, soil erosion control, groundwater flow control, and remediation of soil and groundwater impacted by metals and radionuclides. Challenges in biomediated ground modification include upscaling processes from the laboratory to the field, in situ monitoring of reactions, reaction products and properties, developing integrated biogeochemical and geotechnical models, management of treatment by-products, establishing the durability and longevity/reversibility of the process, and education of engineers and researchers.","chemical properties; environmental engineering; ground improvement; remediation; soil stabilisation","en","journal article","ICE Publishing","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:1400389f-c643-4d44-af41-580c7209e7bb","http://resolver.tudelft.nl/uuid:1400389f-c643-4d44-af41-580c7209e7bb","Utilization of Rice husk ash in GeoTechnology: Applicability and effect of the burning conditions","Pham, P.V.","Van Tol, A.F. (mentor); Van Paassen, L.A. (mentor); Van der Star, W. (mentor); Ye, G. (mentor)","2012","Rice husk ash is an attractive pozzolan. Due to its low cost and high activity it has a promising perspective in sustainable construction. In combination with lime, its effect in soil improvement can be equal to cement treatment but its production process consumes much less energy. The main component of the rice husk ash is silica, which is the element that governs the reactivity of the ash. A delicate burning process is required to eliminate the organic components in the rice husk but keep the silica to be amorphous so that a highly reactive rice husk ash can be obtained. A too high temperature would transform amorphous silica to crystalline silica, which would reduce the reactivity. The suggested burning process in literature is 2 hours at 500oC. However, due to the exothermic property of the burning rice husk it is difficult to control the exact burning temperature, hence there is still a possibility that the carbon and the crystallized silica are present and hinder the activity of the rice husk ash. Based on the silica state and the carbon content, the rice husk ash is classified in three types: C-RHA which is collected from a quick and open-air burning and contains a large amount of carbon; Cr-RHA which is collected form slow burning at above 600oC and contains a large amount of crystallized silica; and A-RHA which is collected from the suggested burning process which is 500oC in 2 hours and is considered to be the most active. The activity of these three types of rice husk ash and their effect in soil improvement were tested. As expected, the higher reactivity of the A-RHA compared with the Cr-RHA confirmed the capability of these burning conditions. Surprisingly, the C-RHA appeared to be the most reactive and its effect to the soil was also the most positive despite of the large carbon content and the detected crystalline silica. The high reactivity of the C-RHA derives that there is a hierarchy of the solubility depending on the burning duration so that although all the three types of ash were mainly amorphous, the C-RHA is the most soluble. From the experiments, the role of the carbon was seen in only the term of quantity as it reduce the proportion of the silica, but might it have any support to the reactivity of the material in those experiments then it needs more investigation. The results of the treated soil showed that the rice husk ash need the lime to be activated, but then it helped to enlarge the possitive effect of the lime. The immediate effect of the additives to the plasiticity of the soil were seen to be the results of the lime only, but the long-term effect of the strength and the compression of the soil were seen to be the results of the combination between rice husk ash and lime. Especially in the case of C-RHA, it can reduce half the amount of lime in the case of 6% lime mixing to give similar undrained shear strength which was about 410 kPa. Because the carbon is not a serious harmful factor in the soil, and the soil can also take the advantage of the firmness of the quartz, so between the two cases, the rice husk ash with large carbon content and also considerable amount of quartz but higher reactivity, and the rice husk ash which is almost purely amorphous silica but less reactive, the former is the preferred for the soil improvement purpose.","rice husk ash; soil improvement; burning conditions; pozzlan; pozzolanic activity; reactive silica","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Geoscience & Engineering","","","",""
"uuid:e068d5a0-07b5-4981-bf9a-027465387dea","http://resolver.tudelft.nl/uuid:e068d5a0-07b5-4981-bf9a-027465387dea","Applying Lean Six Sigma in a multi-department environment: Reducing the rejection of steel slabs within Tata Steel IJmuiden","Van den Berg, R.","Herder, P. (mentor); Lukszo, Z. (mentor); De Bruijne, M. (mentor); Brockhoff, J. (mentor)","2012","This report presents the results of a thesis research project executed at Tata Steel IJmuiden at the technical quality department of the Basic Oxygen Steel plant. This department wanted to reduce the rejection of their produced steel slabs within the internal supply chain of Tata Steel. For this project the Basic Oxygen Steel plant wanted to use the quality improvement method Six Sigma. The project involved several departments because the problem occurs within the internal supply chain of Tata Steel IJmuiden. Therefore this research is interested in a quality improvement method which can be applied in a multi-department setting, whereby different departments have their own goals, own working methods and incentives which may be conflicting. This lead to the main research question: How to improve the performance of an organization within the process industry by implementing improvement measures in different sub-systems with their individual objects and working methods?","Lean Six Sigma; Quality improvement method; Organization structures","en","master thesis","","","","","","","Campus only","2013-03-13","Technology, Policy and Management","Infrastructure Systems & Services","","Energie & Industrie","",""
"uuid:ca59ce6d-ab40-485d-a1a4-b659cd537554","http://resolver.tudelft.nl/uuid:ca59ce6d-ab40-485d-a1a4-b659cd537554","Effect of TIG-dressing on fatigue strength and weld toe geometry of butt welded connections in high strength steel","Van Es, S.H.J.","Bijlaard, F.S.K. (mentor); Kolstein, M.H. (mentor); Pijpers, R.J.M. (mentor); Hendriks, M.A.N. (mentor); Houben, L.J.M. (mentor)","2012","When high strength steels are applicated in dynamically loaded structures, fatigue problems can arise. In most current design codes, the fatigue strength of high strength steels is either not discussed or determined as similar to mild steels. This assumption can be related to the dominance of the crack propagation life during in the total fatigue life when considering welded connections. Weld improvements can increase the length of the crack initiation life and thus increase the total fatigue life and may lead to a difference in fatigue strength between high strength steel and mild steels. This study focuses on the the effects of TIG-dressing on the weld toe geometry and the fatigue strength of TIG-dressed specimens. First a literature study is presented which summarizes earlier researches into the effect of TIG-dressing on fatigue strength and the behaviour of high strength steel in fatigue conditions, both in an as welded situation as after TIG-dressing. The weld toe geometry before and after TIG-dressing is determined. This leads to a extensive data set containing the geometry of the complete weld. The weld toe is then described with the aid of four parameters: weld toe radius, weld toe angle, weld height and undercut. Any influence of the static strength of the material, or any differences between rolled and cast steel are investigated. A comparison is made between the as welded specimens and TIG-dressed specimens. This changed geometry has been coupled to a changed fatigue strength with the aid of the notch stress approach. FEM analyses of the weld toe, based on measured geometries, have been carried out to determine stress concentration factors. Adjustments of the fatigue strength to account for loading mode, thickness, residual stress and mean stress have been derived from literature. A small reduction in residual stress, caused by the TIG-dressing procedure, has also been derived from literature. Fatigue tests have been carried out on 24 specimens ranging from S460 to S1100, made from both cast and rolled steels. The specimens are also adjusted for loading mode, thickness, residual stress and mean stress and compared with the developed model and a larger dataset of comparable as welded specimens. Due to the relatively small number of specimens per steel grade, a reliable quantitative fatigue strength improvement cannot be specified. A extensive qualitative analysis gives insight in the overall trends. From all used plates, hardness measurements are available, which have not been thoroughly analyzed. During the fatigue tests, crack dimensions have been determined during the crack propagation life. These measurements also have not been analyzed. Both data sets are added in annexes and are digitally available at the author or one of the members of the graduation committee.","TIG-dressing; geometry; tests; fatigue; radius; angle; improvement; butt; weld; high; strength; steel","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Structural Engineering","","Steel Structures","",""
"uuid:eca20a26-ef03-431a-b552-68e899a46b7e","http://resolver.tudelft.nl/uuid:eca20a26-ef03-431a-b552-68e899a46b7e","A mathematical model and analytical solution for the fixation of bacteria in biogrout","Van Wijngaarden, W.K.; Vermolen, F.J.; Van Meurs, G.A.M.; Vuik, C.","","2012","Biogrout is a new method for soil reinforcement, which is based on microbialinduced carbonate precipitation. Bacteria and reactants are flushed through the soil, resulting in calcium carbonate precipitation and consequent soil reinforcement. Bacteria are crucially important in the Biogrout process since they catalyse the reaction. Hence, to control the process, it is essential to know where the bacteria are located. The bacteria are possibly in suspension but can also be adsorbed or fixated on the matrix of the porous structure. In this article, a model is derived for the placement of bacteria. The model contains three phases of bacteria: bacteria in suspension, adsorbed bacteria and fixed bacteria. An analytical solution is derived for instantaneous reactions between these three phases. The analytical solution is compared to numerical simulations for finite reaction rates. For the numerical simulations the standard Galerkin Finite Element Method is used.","biogrout · transport of bacteria · microbial-induced carbonate precipitation · soil improvement · analytical solution","en","journal article","Springer","","","","","","","","Electrical Engineering, Mathematics and Computer Science","Delft Institute of Applied Mathematics","","","",""
"uuid:efbaec68-59de-4294-864f-748901e97f8c","http://resolver.tudelft.nl/uuid:efbaec68-59de-4294-864f-748901e97f8c","The application of Value Improving Practices: Team integration pays off!","Rekveldt, M.G.C.; Smith, J.; Mooi, H.G.; Bakker, H.L.M.; Verbraeck, A.","","2011","Submitted paper to: EURAM 2011 Track 30: Project Organizing","front end development; value improving practices; integrated teams; long term relationships; trust","en","conference paper","Estonian Business School","","","","","","","","Technology, Policy and Management","Multi-Actor Systems","","","",""
"uuid:a726f55d-ed87-4524-af53-f3b7d8b9fe69","http://resolver.tudelft.nl/uuid:a726f55d-ed87-4524-af53-f3b7d8b9fe69","Achieving excellence in the aerospace industry: The development of a quality improvement method for innovative engineer-to-order processes at Fokker Services","De Boer, M.A.","Herder, P.M. (mentor); Lukszo, Z. (mentor); De Bruijne, M.L.C. (mentor)","2011","","Six Sigma; engineer-to-order; production processes; quality improvement; aerospace industry","en","master thesis","","","","","","","Campus only","","Technology, Policy and Management","Energy & Industry","","Management of Technology","",""
"uuid:16cec059-45b2-4946-8291-b92b72db8913","http://resolver.tudelft.nl/uuid:16cec059-45b2-4946-8291-b92b72db8913","On 3D Stacked IC Yield Improvement and 3D-DfT Test Architecture","Verbree, J.","Marinissen, E.J. (mentor); Hamdioui, S. (mentor)","2011","Three-dimensional stacked ICs (3D-SICs) based on Through-Silicon Vias (TSVs) is an emerging technology. It provides heterogeneous integration, higher performance and bandwidth, and lower power consumption. However, 3D-SICs suffer from lower compound yield, especially those based on Wafer-to-Wafer (W2W) stacking. In addition, testability of such devices is still in its infancy stage. This thesis addresses these two challenges. To improve the compound yield of W2W 3D-SICs, a technique known as wafer matching will be used. It defines the best matching of top and bottom wafers from repositories of pre-tested wafers. The simulation results show that the compound-yield increase depends on (1) the number of stack tiers, (2) the number of dies per wafer, (3) the die yield, and (4) the repository size. Moreover, they demonstrate that, for realistic cases, relative yield increases of 0.5% to 10% can be achieved. The thesis also proposes a three-dimensional Design-for-Test (3D-DfT) architecture that solves the testability issue of of 3D-SICs. The architecture is based on a modular approach, in which the various dies, their embedded IP cores, TSV-based interconnect, and external I/O can be tested as separate units, before and/or after bonding. Furthermore, the architecture leverages existing 2D DfT already present in the design, and adds a die-level wrapper based on IEEE Std 1500 augmented with additional features in order to be able to deals with 3D-SIC challenges (e.g., to transport signals up and down through the stack). The architecture is implemented and the simulation results show that it provides the flexibility and the modularity is realized at the cost of less than 0.1% area overhead when considering large industrial chips. The architecture could serve as a basis for further standardization of DfT for 3D-SICs.","3D-DfT; Test Architecture; Yield improvement; 3D-SIC; TSV; Wafer matching","en","master thesis","","","","","","","","2011-09-16","Electrical Engineering, Mathematics and Computer Science","Microelectronics & Computer Engineering","","Computer Engineering","",""
"uuid:989451eb-85ad-44b2-97ce-237655ea0748","http://resolver.tudelft.nl/uuid:989451eb-85ad-44b2-97ce-237655ea0748","Retail Performance Scan+: An innovative service for improving the commercial performances in retail","Ho, E.S.H.","Christiaans, H.H.C.M. (mentor); Simonse, L.W.L. (mentor)","2011","","Retailscan; Retail; Industrial Design; Service design; Performance Improvement","en","master thesis","","","","","","","Campus only","","Industrial Design Engineering","Product Innovation Management","","Master of Science Strategic Product Design","",""
"uuid:4dabc07e-47c5-43f4-954e-48bd9f075b10","http://resolver.tudelft.nl/uuid:4dabc07e-47c5-43f4-954e-48bd9f075b10","Integration of Six Sigma and Achieving Competitive Excellence: A case study at Ethiopian Airlines","Nigatu, T.A.","Lukszo, Z. (mentor); Scholten, V.E. (mentor)","2011","Currently organizations are investing large sums of money, time and knowledge to stay competitive and profitable. Driven by strong competition and increasing operational costs, the global aviation industry is under paramount pressure to strengthen operational excellence and improve profitability. Airlines are heavily investing in the means to improve productivity and reduce variation in the maintenance, repair and services processes. Both the well-established and new entrees to the aviation industry need to develop and implement well-developed and proofed quality management system to stay competitive and lead the industry and/or expand to new market segments. A quality management system will help Airlines to meet their customers’ expectation through improved products and services. Ethiopian Airlines (EAL) is facing fierce market competition from European and Middle East airlines such as KLM, Turkish Airlines, Emirates, Qatar and Fly Dubai. EAL implemented Achieving Competitive Excellence (ACE) to improve its performance and stay competitive in the market. ACE is a custom-made system developed by United Technology Cooperation (UTC) and yet not proved useful in other organizations. Its implementation highly depends on organizational culture, company resource and existing quality management system. To understand and exploit advantage of ACE, a detailed investigation of its philosophy, tools, techniques, critical success factors, pre-conditions and (dis-)advantages is established. Furthermore, a detailed comparison and potential benefits of its integration with the well-established quality improvement system Six Sigma, are demonstrated. Six Sigma is a business process improvement approach that seeks to find and eliminate causes of defects and errors, reduce cycle time and cost of operations, improve productivity to meet customer expectations, and achieve higher asset utilization and returns. Six Sigma employs a project-based method that uses statistical and non-statistical tools and techniques to remove process variation and improve process performance and capability. Furthermore, Six Sigma is a data-driven, result oriented and uses well-trained improvement specialists and top-down approach to execute the improvement processes. To thoroughly understand the logical reasoning behind ACE and to improve the rate of ACE implementation, resemblances between ACE and Six Sigma and benefits of integrating of ACE and Six Sigma on organization performance; the main research question is formulated as: “How can Six Sigma be integrated with Achieving Competitive Excellence (ACE) quality management system to reduce products and services variance, and to improve the performance of an organization?” An extensive literature review on business performance, Six Sigma and ACE is carried out to establish a theoretical framework for this research project. The literature finding of ACE is demonstrated with an exploratory case study at EAL. A detailed insight to the practical challenges and barriers of ACE implementation are presented. The findings of the literature review are crafted against the case study in corporation with ACE experts to formulate firm conclusions and recommendations. Organizations must thoroughly identify their strategy, structure and culture, institutional forces, resources and performance measurement system before embarking on ACE and Six Sigma integration. Top management involvement, commitment and leadership is critical for successful integration. A top-down approach is suggested for project prioritization and selection in an integrated Six Sigma and ACE environment. This increases the involvement of top management in continuous improvement processes. Top management translates organization’s strategies to goals and objectives to meet customers’ expectation and remove barriers and obstacles to enhance efficiency and effectiveness of continues improvement programs. Furthermore, top-down approach facilitates integration of stakeholders’ issues; sustained profit, low operational cost, sustainable annual growth and usage of “voice of customer” (VOC) as an input to project selection process. The introduction of Design for Six Sigma (DFSS) in design and development of new products and services leads to sustainable business operation in a dynamic market environment by delivering high quality products and services to their customers with at lower-cost. DFSS benefits ACE with by reducing product development cycle and high production efficiency and effectiveness. Six Sigma’s tools like design of experiment (DOE), analysis of variance (ANOVA), linear regression analysis, multivariate SPC and other improve process certification process and reduce process variation. The benefits of these tools further extend to problem solving and decision making through relentless root cause analysis. Thus, ACE and Six Sigma integration extends the benefits of these tools to ACE. In cooperating environment/ community and employee’s satisfaction perspectives in the existing balanced scorecard (BSC) extends business performance measurement to more dimensions. The new perspectives together with BSC‘s four perspectives are smoothly translated to ACE Control Tower six categories at strategic level. This helps to track, monitor and evaluate the effect of ACE or integrated Six Sigma and ACE on organization strategies and performance. An Action-learning model facilitates understanding the current situation and employee’s perceptions and involvement in an improvement process. The model helps organizations to bring organizational change and to create a clear understanding of current situation. Action-learning model play a great role in bringing paradigm shift from result-oriented to means driven culture and in developing safe practice field to support network (community of practice) of fellow employees. A well-structured Cell formation guideline that defines the number of employees per Change Agents per Cell, ways to weight operational activities in a Cell and ability to solve conflicts of interest between sections in a Cell must be developed. To reduce employees’ turnover and internal transfer, an incentive or compensation plan for those Cells with excellence business performance must be put in place. Moreover, organizations should create knowledge management system to capture the tacit knowledge from senior quality management experts. The integration makes ACE more data and fact driven, execute process certification on project basis with top-down approach, total value chain gets more focus, improve new products and services design and increased employees and suppliers involvement and get other benefits.","Six Sigma; Process Improvement; Quality Improvement; Achieving Competitive Excellence","en","master thesis","","","","","","","Campus only","","Technology, Policy and Management","Management of Technology","","Energy and Industry","",""
"uuid:97be8e09-9f81-44a7-88dd-d5bbbb4ad069","http://resolver.tudelft.nl/uuid:97be8e09-9f81-44a7-88dd-d5bbbb4ad069","Between marketing and financial support: Dutch municipal policy instruments to improve the quality of private housing stock","Tambach, M.; Meijer, F.; Visscher, H.","","2011","Dutch municipalities are faced with an ageing private housing stock, of which parts show a diversity of quality backlogs, including their energy quality. Dutch municipalities are in the process of developing a combination of communicative and economic policy instruments to seduce private homeowners to invest in their dwellings quality. Homeowners willingness and capability to invest, and their level of organization play key roles here. This paper investigates, if the applied policy instruments to improve the quality of private housing stock in three Dutch municipalities are effective as well as cost-effective for both municipal governments and private homeowners. First results indicate that municipalities are marketing quality improvements to private homeowners by organizations that support and communicate with homeowners, but yet it seems without the hoped-for large-scale improvements. A multi-level policy approach seems to be needed for private dwelling improvement to become successful. This implies an improved playing field shaped by the national government, in which municipalities can make use of their local long-term oriented economic policy instruments more efficiently, such as property taxes and rebates on such taxes for (e.g. energy) quality improvements.","Dutch municipal policy instruments; quality improvement of private housing stock","en","conference paper","","","","","","","","","","","","","",""
"uuid:6ae1b764-87c9-490d-babe-101a8581e659","http://resolver.tudelft.nl/uuid:6ae1b764-87c9-490d-babe-101a8581e659","Between marketing and financial support: Dutch municipal policy instruments to improve the quality of private housing stock","Tambach, M.; Meijer, F.; Visscher, H.","","2011","Dutch municipalities are faced with an ageing private housing stock, of which parts show a diversity of quality backlogs, including their energy quality. Dutch municipalities are in the process of developing a combination of communicative and economic policy instruments to seduce private homeowners to invest in their dwellings’ quality. Homeowners’ willingness and capability to invest, and their level of organization play key roles here. This paper investigates, if the applied policy instruments to improve the quality of private housing stock in three Dutch municipalities are effective as well as cost-effective for both municipal governments and private homeowners. First results indicate that municipalities are marketing quality improvements to private homeowners by organizations that support and communicate with homeowners, but yet it seems without the hoped-for large-scale improvements. A multi-level policy approach seems to be needed for private dwelling improvement to become successful. This implies an improved playing field shaped by the national government, in which municipalities can make use of their local long-term oriented economic policy instruments more efficiently, such as property taxes and rebates on such taxes for (e.g. energy) quality improvements.","Dutch municipal policy instruments, quality improvement of private housing stock","en","conference paper","Delft University of Technology","","","","","","","","OTB Research Institute for the Built Environment","","","","",""
"uuid:88e9ff01-8a67-4d31-9aa8-420d769661e0","http://resolver.tudelft.nl/uuid:88e9ff01-8a67-4d31-9aa8-420d769661e0","Measure, understand and improve cities: Visualizing pedestrian flows to improve inner-city quality in Delft using GPS-tracking technology","Van Langelaar, C.M.","Rooij, R.M. (mentor); Van der Spek, S.C. (mentor); Van Dorst, M.J. (mentor)","2011","We all have walked on a street when suddenly someone comes over to you asking for directions. Sometimes, people do not know where they are and they do not know how to reach their destination. They are lost. However, people should not depend on others to find their way. The urban fabric should be legible enough to find one’s way. The problem statement of this Master Thesis is that people should wander and stroll through the urban fabric instead of getting lost. Consequently, for the graduation project we zoom in to one of the many aspects of “good public space”, namely the element ‘wayfinding’. What is good public space in relation to pedestrian’s ability to orientate themselves in the historic city centre? The first chapter deals with wayfinding, its definitions, how it is related to the city centre of Delft, environmental psychology and urban economy. The aim of the graduation project is to better understand how people navigate in cities in order to develop recommendations for urban planning and design to make city visits more enjoyable, engaging and involving for pedestrians. The main research question for the graduation project is: “Which strategic spatial design interventions can improve public space for the slow traffic network in order to retain city visitors in the city centre of Delft?” This subject will be solved by answering four sub-research questions: (i) What are criteria for successful public spaces looking at pedestrians walking in city centres? (ii) What is the current quality of the streets and built environment in the city centre of Delft? (iii) Do pedestrians (visitors/tourists, city centre inhabitants and neighbourhood residents) use the public space in the city centre of Delft differently? (iv) How can the criteria for successful public spaces, the analysis of the current situation and the conclusions of how people use the city centre be embedded in strategic spatial (navigational) recommendations for the city centre of Delft? Applied methods in order to answer the sub-research questions are: (ad i) Literature review studies (a general study about good public space and a specific wayfinding study). (ad ii) Evaluation of the city centre by mapping urban facilities, making a Three-Step analysis, measuring walking distances from two garages, visibility graph analysis, history of Delft by a morphology analysis, quality analysis perception of the city centre based on participants’ questionnaires and a visual analysis (photographs). (ad iii) Actual pedestrian movement is gathered and mapped by doing two GPS-tracking research pilots in the city centre of Delft (a) November 2009: following visitors/tourists who park their car in the Phoenix or Zuidpoort garage and who continue their journey on foot (b) April/May 2010: following city centre inhabitants and neighbourhood residents of Delft. Results are mapped in ArcGIS and statistics are made in SPSS and Excel. Behaviour of the three different pedestrian groups is compared, where after results and conclusions are noted. (ad iv) All gathered information is put into a self made GPS-flowchart: the model shows a researcher in four steps which strategic interventions are recommended for a project area. To answer the main research question, first a future vision of Delft 2030 is described which is followed by a mission, vision and strategy for the city centre of Delft. Consequently, strategic spatial design interventions are proposed, divided into conservative short term and ambitious long term scenarios. The GPS-flowchart is used to determine a strategy for a specific area in the city centre. Due to the fact that there is an enormous amount of data available, several tips for follow-up research are suggested.","urban environment; historic; city centre; visualisation; pedestrian movement; walking; measuring; understanding; improving; spatial quality; GPS; tracking; good public space; wayfinding; environmental psychology; urban economy; GIS; SPSS; city centre evaluation; urban facilities; three-step analysis; walking distances; visibility graph analysis; quality analysis perception; visual quality analysis; density analysis; used streets; non-used streets; mission; vision; strategy; spatial interventions; BCG-matrix; star; cash cow; question mark; dog","en","master thesis","","","","","","","","2011-05-12","Architecture","Urbanism","","Studio Urban Acupuncture","",""
"uuid:bc7de309-ee61-46c2-8962-e4d8a10e71d7","http://resolver.tudelft.nl/uuid:bc7de309-ee61-46c2-8962-e4d8a10e71d7","The Japanisation of the Dutch railways","Van de Velde, D.M.","","2011","","railway management; continuous improvement; international learning; Dutch railways; Japanese railways","en","journal article","","","","","","","","","Technology, Policy and Management","Multi Actor Systems","","","",""
"uuid:d29a4ce6-880a-416c-a189-0304f8ae0cdb","http://resolver.tudelft.nl/uuid:d29a4ce6-880a-416c-a189-0304f8ae0cdb","The effect of filter jacket clogging on the performance of prefabricated vertical drains in soft soils","Kochx, J.P.","Van Paassen, L.A. (mentor); Ngan-Tillard, D.J.M. (mentor); Dijkstra, J.W. (mentor)","2011","Prefabricated vertical drains (PVD) are used to accelerate drainage and consolidation of soft sediment. An effective functioning of these PVD depends on its capacity to drain water from the subsurface. Among other causes, the clogging of filter jackets is thought to be of a considerable negative influence on the functioning of PVD. Current regulations prescribe a minimum ratio between the filters aperture size and the grain size distribution of the soil to prevent this clogging. Objective: The objective of this thesis was to evaluate the effect of filter clogging on the performance of PVD filter jackets, with regards to the soft soil conditions that are encountered in large parts of the Netherlands. Method: A literature review is performed on the principle of vertical drainage, soil types, filter types, clogging criteria, processes and testing methods. An experimental program was undertaken in the laboratory in which filter jackets were exposed to two different clogging phenomena, i.e. particle clogging and chemical clogging. Also filters from the field were evaluated. All filters were evaluated on their loss of permittivity with constant head measurements on filter pieces of three different filter types, the D165 and HS5417 from the Typar line of DuPont and the 30195 of Freudenberg. Particle clogging was evaluated by two different setups, the Oedometer and a long term filtration setup. Within the Oedometer tests the load and the moisture content of the clay sample varied. Chemical testing was done briefly, to see till what extend iron precipitation could induce filter clogging and if one filter would be more prone to clog than the other. Results: The permittivity tests on the filter pieces showed reproducible results. Repeated measurements on the same sample showed an average standard deviation of not larger than four percent of the samples mean. The initial permittivity also corresponded reasonable with the values provided by the filter manufacturers. With particle clogging, it was seldom observed that clogging ratios were higher than five. Relations between clogging and the applied load on the clay sample could not be found. Increasing moisture content showed a slightly higher clogging ratio. Another clogging indicator was found from work by Aydilek, initial permittivity. This is believed to be a better estimator; higher initial permittivity in general gave lower clogging ratios. In the chemical experiment it was observed that on the filter of Freudenberg large amounts of iron oxide precipitated. During filtration the filter seemed fully clogged. Permittivity tests on this filter showed an approximately four times larger clogging ratio, than that of the other ones. Conclusions: Based on literature and observations from both experiments and field data, it can be concluded that the permittivity reduction of filter jackets is always less than a factor of ten. Hence filter clogging is not a real issue, since the permeability of the soft sediments is several orders of magnitude lower than that of the clogged filters. Hence, the system permeability is mainly determined by the soil behavior.","geosynthetics; particle clogging; chemical clogging; ground improvement; prefabricated vertical drains; filter jackets; nonwoven","en","master thesis","","","","","","","","2013-03-22","Civil Engineering and Geosciences","Geotechnology","","Geo-Engineering","",""
"uuid:0836a855-40d9-4cf1-9100-fcf853df09f3","http://resolver.tudelft.nl/uuid:0836a855-40d9-4cf1-9100-fcf853df09f3","The Effect of Porefill on Pre- and Post-stack Seismic Data in a Dutch Buntsandstein Reservoir","Auduson, A.E.","Andries, W. (mentor); Arts, R.J. (mentor)","2010","Wintershall is operating a number of Buntsandstein fields in the Southern North Sea. It has proven a major exploration challenge in the area to predict the reservoir quality of these fields based on seismic data only. The effect of salt present in the area plugging the pore space leads at first sight to similar seismic responses on post-stack data as for gas filled reservoirs. This study aims to gain better insight into the (subtle) differences in seismic response induced by water-, gas- or salt-fill scenario. The approach adopted is by studying the seismic response at various existing wells in one of the fields and the corresponding seismic responses of the processed 3D seismic survey. First a thorough analysis of the log responses of 13 wells is made and the effect of a.o. depth trends, compaction, diagenesis and facies changes to the seismic response is qualitatively investigated. Then, a match between the log data and the poststack seismic data is established by creating synthetic seismic data. Finally by using fluid substitution and more recent solid substitution theory, subtle changes in seismic response, both pre-stack and post-stack, between the different porefills are predicted. Based on these modeled predictions recommendations are made concerning the type of data analysis that should be carried out to discern the different porefills on the seismic data. The results of this research should lead to an improved characterization of the Buntsandstein reservoirs and as a consequence, to a higher success rate in drilling (i.e. less “dry wells”).","exploration challenge; seismic response; synthetics; reservoir quality; improved characterization; post-stack; pre-stack; Buntsandstein","en","master thesis","","","","","","","","","Civil Engineering and Geosciences","Geotechnology","","Applied Geophysics and Petrophysics","",""
"uuid:9c0f1a9a-1cd7-47aa-885e-c0938faeedec","http://resolver.tudelft.nl/uuid:9c0f1a9a-1cd7-47aa-885e-c0938faeedec","River capacity improvement and partial floodplain reactivation along the Middle-Tisza - Scenario analysis","Tóth, S.","TU Braunschweig","2009","The research output describes the results of analysis of factors of river capacity problems along the Middle-Tisza section, scenario analysis of intervention options to raise the flood conveyance capacity of the flood bed, scenario analysis of partial floodplain reactivation with controlled inundation. Individual and combined effects of river capacity improvement, selected detention basins as well as combined effect of river capacity improvement and flood detention was investigated. Results of modelling are summarised and form important input of the design and implementation of the flood hazard reduction programme of the region called Update of the Vásárhelyi Plan.","Hydrological modelling; River; River capacity improvement","en","report","Vituki Hungary","","","","","","","","","","","","Floodsite",""
"uuid:fedbe4bc-52d5-4374-b8d9-b620bd0f3448","http://resolver.tudelft.nl/uuid:fedbe4bc-52d5-4374-b8d9-b620bd0f3448","Real-time reduced basis techniques for Navier-Stokes equations: Optimization of parametrized bypass configurations","Rozza, G.","","2006","The reduced basis method on parametrized domains is applied to approximate blood flow through an arterial bypass. The aim is to provide (a) a sensitivity analysis for relevant geometrical quantities of interest in bypass configurations and (b) rapid and reliable prediction of integral functional outputs ( such as fluid mechanics indexes). The goal of this investigation is (i) to achieve design indications for arterial surgery in the perspective of future development for prosthetic bypasses, (ii) to develop numerical methods for optimization and design in biomechanics, and (iii) to provide an input-output relationship led by models with lower complexity and computational costs than the complete solution of fluid dynamics equations by a classical finite element method.","design of improved biomechanical devices; parametrized PDEs; Navier-Stokes equations; reduced basis methods; bypass optimization; haemodynamics","en","conference paper","","","","","","","","","","","","","",""
"uuid:7176b87c-ae1a-4a9c-be60-d72a2e0120e8","http://resolver.tudelft.nl/uuid:7176b87c-ae1a-4a9c-be60-d72a2e0120e8","Research into a ""Shipbuilding coordination centre"" Modelling the processes and Organisational structure","van Prooijen, E.","","2005","","organisation; modelling; improving; purchasing","","master thesis","","","","","","","","indefinite","Mechanical, Maritime and Materials Engineering","Marine and Transport Technology","Ship Design, Production and Operation","","",""
"uuid:42de6c5d-f420-4733-ae1b-813dbafb24e2","http://resolver.tudelft.nl/uuid:42de6c5d-f420-4733-ae1b-813dbafb24e2","New strategies for housing quality improvement by Dutch landlords","Straub, A.; Vijverberg, G.A.M.","","2004","","Accessibility, Facilities, Housing quality; Improvements; Plan features; Social Landlords; Strategies","en","journal article","Open House International Association","","","","","","","","OTB","","","","",""
"uuid:37060d41-f576-4ef4-b716-6c72bc635e22","http://resolver.tudelft.nl/uuid:37060d41-f576-4ef4-b716-6c72bc635e22","Rivierkundige analyses maatregelen benedenrivierengebied ten behoeve van PKB ruimte voor de rivier","Verschelling, E.","","2003","","rivierbeheer; river management; rivierverbreding; riverbed widening; rivierverbetering; river improvement; benedenrivieren; lowland rivers","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:51835ae7-10fe-416f-86fd-1c517665c0b7","http://resolver.tudelft.nl/uuid:51835ae7-10fe-416f-86fd-1c517665c0b7","Invloed van ingrepen in het mondinggebied van de Westerschelde: Evaluatie aan de hand van ESTMORF berekeningen","Wang, Z.B","","2003","","kustmorfologie; coastal morphology; riviermorfologie; river morphology; rivierverbetering; river improvement; vaargeulen; navigation channels; kustverdediging; coast protection; Westerschelde","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:842297d4-09f6-4340-a27a-979dcfd55711","http://resolver.tudelft.nl/uuid:842297d4-09f6-4340-a27a-979dcfd55711","A decade of ERS satellite orbits and altimetry","Scharroo, R.","Wakker, K.F. (promotor)","2002","The First European Remote Sensing Satellite, ERS-1, was launched in July 1991, fol- lowed by ERS-2 in April 1995. Both satellites carry a radar altimeter to serve oper- ational applications and scientific research in the fields of geodesy, oceanography, glaciology and meteorology. Together, the satellites have now been operating for over twelve years. This thesis embarks on the a voyage along several milestones in the lifetime of these satellites, and particularly of its altimeters. Both altimeter missions were hampered by a number of misfortunes, ranging from hardware failures, via design mishaps, to a sub-optimally designed ground segment. Yet, the altimeter data, when properly processed and supplied with a precise orbit, can compete favourably with data supplied by specialised altimeter satellites like TOPEX/Poseidon and Jason-1. The upgrading of all altimeter cor- rections and the tweaking of the basic altimeter measurements of range, significant wave height and backscatter coefficient, are essential steps in this process, outlined in this thesis. Having accomplished that, the ERS altimeters allow the monitor- ing of annual, semi-annual and secular changes in sea level, which are important factors in study of climate change. A key role in the processing of altimeter data plays the position of the satellite, and its progress in time, the satellite orbit. The quality of the recovered sea surface height is limited by the precision at which the orbit can be determined. A long journey along several stepwise improvements of the orbit determination process, both in the technique as well as in the modelling, have resulted in the reduction of the orbit error by a factor of 30! A major player in this process was the estab- lishment of a gravity field model tailored to the ERS satellites that, when applied to ERS orbit determination, outperformed any of the previous and contemporary general-purpose models. Yet, it is shown that this model, DGM-E04, is not just a fabrication for the benefit of ERS only, but is equally suitable for the orbit determ- ination of TOPEX/Poseidon and as a long-wavelength geoid model. The calibration of the ERS-1 altimeter in 1991 required, at a time when the orbit errors were still counted in decimetres, if not metres, a short-arc orbit determin- ation technique centred over the calibration site off the coast of Venice. Again, through elaborate surveying, gathering of altimeter corrections and tide gauge measurements, problem solving and elimination of errors, a final absolute range bias of 41.5 cm was established, a value that is still within the error margins of more recent estimates. A timing error in the ERS altimeter data was discovered in 1995 and its cause remained a mystery ever since, especially when the timing error appeared to ex- hibit daily, annual and inter-annual variations as well. Although the exact cause may never be found, the issue is examined in fine detail and a model is constructed to eliminate the timing error for the benefit of the quality of the altimeter data.","satellite orbit determination; satellite altimetry; gravity field improvement; ERS-1; ERS-2","en","doctoral thesis","","","","","","","","","Aerospace Engineering","","","","",""
"uuid:ca022dc8-b0ac-4278-a4c8-22a53f1e81c5","http://resolver.tudelft.nl/uuid:ca022dc8-b0ac-4278-a4c8-22a53f1e81c5","Room for the Rhine in The Netherlands: Summary of research results","Klijn, F.; Dijk, J. van; Silva, W.","","2001","","rivierverbetering; river improvement; rivierverruiming; riverbed widening; hoogwaterbeheer; flood management; rivierafvoer; discharge; Rijn; Rhein","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:2f0ccb93-df0c-4812-8b3c-6d543cfc49fa","http://resolver.tudelft.nl/uuid:2f0ccb93-df0c-4812-8b3c-6d543cfc49fa","Raum für den Rhein in den Niederlanden: Zusammenfassung der Untersuchungsergebnisse","Klijn, F.; Dijk, J. van; Silva, W.","","2001","","rivierverbetering; river improvement; rivierverruiming; riverbed widening; hoogwaterbeheer; flood management; rivierafvoer; discharge; Rijn; Rhein","de","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:694082cc-c327-491a-ab8b-6e82a7643e35","http://resolver.tudelft.nl/uuid:694082cc-c327-491a-ab8b-6e82a7643e35","Ruimte maken voor de Rijn: Samenvatting van wat het onderzoek heeft opgeleverd","Klijn, F.; Dijk, J. van; Silva, W.","","2001","","rivierverbetering; river improvement; rivierverruiming; riverbed widening; hoogwaterbeheer; flood management; rivierafvoer; discharge; Rijn; Rhein","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:7a5f60e9-36d2-4311-beda-881972d6ab10","http://resolver.tudelft.nl/uuid:7a5f60e9-36d2-4311-beda-881972d6ab10","Grouting for Pile Foundation Improvement","Van der Stoel, A.E.C.","Van Tol, A.F. (promotor); Van Stigt, J. (promotor)","2001","The aim of this research was to examine the use of grouting methods for pile foundation improvement, a generic term that is used here to define both foundation renovation (increasing the bearing capacity of a pile foundation that has insufficient bearing capacity) and foundation protection (safeguarding the piles of the foundation against possible damage resulting from underground construction activities in the vicinity). A full-scale test, of which the general set-up and consistency check are outlined in the thesis, examining the feasibility of foundation improvement by means of grouting techniques was conducted in Amsterdam. The main part of the thesis focuses on permeation grouting, jet grouting and compaction grouting. For each method, first some more general aspects like history, grouting equipment, grouting parameters and fields of application are outlined. Subsequently existing theories used in modelling the grouting process are examined and compared. The test results are discussed. By using the pile displacements, soil stresses, pore pressures and pile bearing capacity measured in the test, it was possible to examine the influence of grouting methods on pile foundations. The use of and suitability of geophysical verification methods for grouting, which were necessary to determine the shape and position of grouted elements, were also considered. To determine how grouting methods can best be applied for foundation renovation purposes, the cost of grouting methods and the hindrance that they cause have been compared with those of conventional foundation renovation methods. The construction cost of grouting can be up to about 50% lower than that of conventional methods of underpinning a structure. Taking cost, hindrance and the test results into consideration, it can be concluded that permeation grouting and compaction grouting are economic and effective alternatives to conventional underpinning methods for renovating pile foundations. The methods may also be used for pile foundation protection. Jet grouting is only suitable for use in the renovation of end bearing piles when the structure is strong and stiff enough to redistribute the loads from the grouted pile. Jet grouting is very suitable for use in protecting pile foundations because it can be applied in any type of soil.","grouting; pile foundation improvement; geophysical verification methods","en","doctoral thesis","Delft University Press","","","","","","","","Civil Engineering and Geosciences","","","","",""
"uuid:69ea3206-050b-485e-a09e-005aa01bed55","http://resolver.tudelft.nl/uuid:69ea3206-050b-485e-a09e-005aa01bed55","A short overview of reflection formulations and suggestions for implementation in SWAN","Kieftenburg, A.T.M.M.","","2001","The reflection implemented in SWAN version 40.11 is just specular reflection. It gives the mirror image of the action density spectrum, cutting it off for all directions that are not directed towards the obstacle and multiplying it by the reflection factor C_r^2 (square because the reflection factor is w.r.t. wave height). To improve the performance of the reflection in SWAN, a small study was made on what is known from literature. Further, some analogy is made with the field of optics, concerning diffuse reflection and scattered reflection effects. To avoid confusion: only reflection at obstacles is considered here. The scattered reflection or scattering that is discussed here is NOT what civil engineers may call Bragg scattering.","reflection; SWAN; wave reflection; reflection on objects; preformance improvement","en","report","TU Delft, Department of Hydraulic Engineering","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:78cdab33-eeb2-424a-89eb-11c5f6fcd1dd","http://resolver.tudelft.nl/uuid:78cdab33-eeb2-424a-89eb-11c5f6fcd1dd","Knowledge Management in Courseware Development","Van Aalst, J.W.","Dietz, J.L.G. (promotor); Kempen, G.A.M. (promotor)","2001","Educational multimedia software development is a special case of software development, partly because of the large variety of disciplines involved, partly because the use of the multiple media sets its own demands to the design and realization of educational software (courseware). In this thesis we investigate the improvement of the maturity of the courseware development process. To this end, we employ a particular kind of knowledge management to facilitate project development teams in their knowledge needs. The results indicate that this particular kind of knowledge management can indeed contribute significantly to the maturity of the development process.","educational multimedia; software process improvement; knowledge management","en","doctoral thesis","Delft University Press","","","","","","","","Information Systems and Technology","","","","",""
"uuid:97767055-f985-446c-aac8-7d80db65c071","http://resolver.tudelft.nl/uuid:97767055-f985-446c-aac8-7d80db65c071","Video-based monitoring of the Egmond beach- and shoreface nourishments: Evaluation of the 1999 nourishments with the help of the Argus video system","Caljouw, M.","","2000","","strandverbetering; beach improvement; zandsuppletie; sand nourishment; kustlijnontwikkeling; coastline development; morfodynamische modellen; morphodynamic models; beeldverwerking; image processing; Noord-Holland","en","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:0ab004ec-1cec-47da-b617-0b129a67b58a","http://resolver.tudelft.nl/uuid:0ab004ec-1cec-47da-b617-0b129a67b58a","Onafhankelijk onderzoek Markermeer - technisch inhoudelijke en integrerende studie, verslag fase 3: Maatregelen en kosten voor dijkverbeteringen als ware het Markermeer buitenwater","Graaff, R.F. de","","1998","","Markermeer; dijkverbetering; dike improvement","nl","report","Deltares (WL)","","","","","","","","","","","","",""
"uuid:10dca27f-efaf-499c-b438-5ed144de1678","http://resolver.tudelft.nl/uuid:10dca27f-efaf-499c-b438-5ed144de1678","Jetgrouten, precisie met geweld","Van Dalen, J.W.","Admiraal, B.J. (mentor); Bezuyen, K. (mentor); Polen, B. (mentor); Van Tol, A.F. (mentor)","1997","Jetgroutkolommen worden gevormd door onder hoge druk een groutmengsel in de grond te injecteren. De grond wordt versneden, losgewoeld en vermengd met de gernjecteerde vloeistof. Door de boorbuis roterend te trekken ontstaat een cilindervormig element. Afbankelijk van het gekozen systeem geschiedt het snijden met dezelfde of met een andere straal dan het mengen. Gesproken wordt van het 1, 2 of 3 fase(n) systeem jetgrouten. De jetgroutkolommen kunnen na uitharding worden gebruikt als waterremmend en/of constructief element. Jetgrouten kan in iedere grondsoort worden toegepast. De ervaring in Nederland met de jetgroutechniek is beperkt tot enkele werken. Visser & Smit Bouw is vooralsnog de enige aannemer in Nederland die beschikt over het benodigde materieeI. De diameter en de sterkte van de kolom worden bepaald door de uitvoeringsparameters en de grondeigenschappen, samen de invoerparameters van het systeem. Onder de uitvoeringsparameters wordt verstaan de injectiedruk, het injectiedebiet, de luchtdruk, de treksnelheid, rotatiesnelheid e.d. De belangrijke grondeigenschappen zijn de cohesie, de dichtheid en het poriengehaIte. De moeilijkheid bij de techniek betreft het voorspeIIen van het resultaat (diameter en sterkte) op basis van de invoerparameters. Het doel van dit onderzoek is tweezijdig. Enerzijds is gezocht naar verbanden en relaties tussen de invoerparameters en het resultaat en anderzijds is gekeken naar de uitvoeringsaspecten van de techniek. Dit laatste betreft ook een meetmethode voor de diameter tijdens de uitvoering van de kolommen. In het kader van de bouw van een tramtunnel in het centrum van Den Haag, het zogenaamde Souterrain, is een uitgebreide jetgroutproef op ware grootte uitgevoerd. Het doel van de proef was het bepalen van de uitvoeringsparameters voor het maken van een groutboog die de waterafsluiting aan de onderzijde van de bouwput vormt. Het 2 en 3 fasen systeem is beproefd, waarbij gevarieerd is met injectiedrukken, debieten, treksnelheden en water/cement-factoren. Tijdens de uitvoering zijn met behulp van een spinapparaat diameterbepalingen gedaan en zijn verse monsters aan de kolom en retourspoeling onttrokken. Na uitharding van de proefkolommen is de put ontgraven, zodat het resultaat kon worden bestudeerd. Vit de kolommen zijn kernen geboord die aan druk- en splijttesten zijn onderworpen. Dit verslag bevat de beschrijving en de analyse van de jetgroutproef. Onderscheid is gemaakt tussen volumieke massa en sterkte van de verschilIende monsters en de diameter van de kolom. Het jetgroutproces is te complex om te komen tot een aIIes omvattend rekenkundig verband tussen het resultaat en de invoer. Het grote probleem blijft het betrekken van de eigenschappen van de grond in een berekening. Toch zijn enkele interessante bevindingen gedaan. De belangrijkste bevinding is de relatie tussen de invoer en het diameterresultaat via de begrippen hydraulische of kinetische energie van de snijstraaI. De hydraulische energie wordt berekend met de snijdruk, het snijdebiet en de treksnelheid, terwijl de kinetische energie wordt berekend met de massa en snelheid van de vloeistof en de treksnelheid. Indien de energiesoorten tegen de diameter worden uitgezet, ontstaat een energiekromme. Deze kromme ligt voor ieder systeem en grondsoort anders en kan worden gebruikt bij het vaststelIen en vergelijken van de uitvoeringsparameters. Voordat met een jetgroutwerk wordt begonnen moet een grondonderzoek worden uitgevoerd, zodat de grondeigenschappen over het te grouten traject in kaart gebracht kunnen worden. Op deze wijze kan tijdens het jetgrouten worden geanticipeerd op wijzigingen in bodemgesteldheid, zodat de kwaliteit van de kolommen gehandhaafd blijft. Met behulp van diameterbepalingen met bijvoorbeeld een spinapparaat kan de diameter vlak na het jetgrouten worden gemeten.","jetgrouting; soil improvement; foundation engineering; grout; pile foundation","nl","master thesis","","","","","","","","","Civil Engineering and Geosciences","Hydraulic Engineering","","","",""
"uuid:b3f5752a-60db-4313-84bb-0fc41b91456f","http://resolver.tudelft.nl/uuid:b3f5752a-60db-4313-84bb-0fc41b91456f","SUBSTITUTION OF TRAVEL DEMAND BETWEEN CAR AND PUBLIC TRANSPORT: A DISCUSSION OF POSSIBILITIES","Bovy, P.H.L.; Van Der Ward, J.; Baanders, A.","","1991","","Conference 8525 car 1243 public transport 1165 transport mode 1145 selection 9072 improvement 9108 attitude psychol 2267 journey 0698 netherlands 8078 policy 0143 traffic restraint 0633 Traffic and transport planning (72)","en","conference paper","PTRC EDUCATION AND RESEARCH SERVICES LTD, GLENTHORNE HOUSE, HAMMERSMITH GROVE, LONDON, W6 0LG, UNITED KINGDOM","","","","","","","","","","","","",""
"uuid:ef7b6da2-fbb4-4011-90ab-c3a7daac836f","http://resolver.tudelft.nl/uuid:ef7b6da2-fbb4-4011-90ab-c3a7daac836f","SUBSTITUTIEMOGELIJKHEDEN TUSSEN AUTO EN OPENBAAR VERVOER.; SUBSTITUTION OF TRAVEL DEMAND BETWEEN CAR AND PUBLIC TRANSPORT.","Baanders, A.; Bovy, P.H.L.; Van Der Hoorn, A.; Van Der Waard, J.","","1991","","Car 1243 public transport 1165 selection 9072 improvement 9108 behaviour 9001 journey 0698 attitude psychol 2267 Traffic and transport planning (72)","nl","journal article","","","","","","","","","","","","","",""
"uuid:a1100c5a-e27e-4a87-bc8b-edbee261ab67","http://resolver.tudelft.nl/uuid:a1100c5a-e27e-4a87-bc8b-edbee261ab67","HOE KAN DAT NOU? DE DISCUSSIE OVER DE SUBSTITUTIEMOGELIJKHEDEN TUSSEN AUTO EN OPENBAAR VERVOER.; HOW IS THAT POSSIBLE? THE DISCUSSION ON THE SUBSTITUTION OF TRAVEL DEMAND BETWEEN CAR AND PUBLIC TRANSPORT.","Bovy, P.H.L.; Baanders, A.; Van Der Waard, J.","","1990","","Conference 8525 car 1243 public transport 1165 selection 9072 improvement 9108 journey 0698 behaviour 9001 attitude psychol 2267 Traffic and transport planning (72)","nl","conference paper","COLLOQUIUM VERVOERSPLANOLOGISCH SPEURWERK, GEERDINKHOF 237, AMSTERDAM, 1103 PZ, NETHERLANDS","","","","","","","","","","","","",""