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Reliable and Energy-efficient Diabetic Retinopathy Screening using Memristor-based Neural Networks

Diware, S.S. (author), Chilakala, Koteswararao (author), Joshi, Rajiv V. (author), Hamdioui, S. (author), Bishnoi, R.K. (author)

Diabetic retinopathy (DR) is a leading cause of permanent vision loss worldwide. It refers to irreversible retinal damage caused due to elevated glucose levels and blood pressure. Regular screening for DR can facilitate its early detection and timely treatment. Neural network-based DR classifiers can be leveraged to achieve such screening in...

journal article 2024

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Economic optimization of coastal flood defence systems including storm surge barrier closure reliability

Mooyaart, L.F. (author), Bakker, A.M.R. (author), van den Bogaard, Johan A. (author), Rijcken, T. (author), Jonkman, Sebastiaan N. (author)

Storm surge barriers are large movable hydraulic structures which close during a storm surge to prevent coastal floods. In the regions they protect, a failure to close the barrier is often the most likely cause for a catastrophic flood. Nevertheless, flood risk assessments usually only focus on raising flood defences behind the barrier....

journal article 2023

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Overview of Wide/Ultra-Wide Bandgap Power Semiconductor Devices for Distributed Energy Resources

Mazumder, Sudip K. (author), Voss, Lars F. (author), Dowling, K.M. (author), Conway, Adam (author), Hall, David (author), Kaplar, Robert J. (author), Pickrell, Greg (author), Flicker, Jack (author), Binder, Andrew (author)

This article provides an overview of power semiconductor devices (PSDs) for the distributed energy resource (DER) system. To begin with, an overview of electrically triggered silicon carbide (SiC) and gallium nitride (GaN) devices followed by a brief narration of ultrawide bandgap (UWBG) PSDs and, subsequently, an overview of optically...

journal article 2023

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Lifetime Prediction of Current-and Temperature-Induced Degradation in Silicone-Encapsulated 365 nm High-Power Light-Emitting Diodes

Herzog, Alexander (author), Benkner, Simon (author), Zandi, Babak (author), Buffolo, Matteo (author), van Driel, W.D. (author), Meneghini, Matteo (author), Khanh, Tran Quoc (author)

We report on the degradation mechanisms and dynamics of silicone encapsulated ultraviolet A (UV-A) high-power light-emitting diodes (LEDs), with a peak wavelength of 365nm. The stress tests were carried out for a period of 8665 hours with forward currents between 350mA and 700mA and junction temperatures up to 132°C. Depending on stress...

journal article 2023

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Evaluating the impact of waiting time reliability on route choice using smart card data

Shelat, S. (author), Cats, O. (author), van Oort, N. (author), van Lint, J.W.C. (author)

Unreliable waiting times may cause frustration and anxiety amongst public transport travellers. Although the effect of travel time reliability has been studied extensively, most studies have used stated preferences which have disadvantages, such as an inherent hypothetical bias, or have analysed revealed preferences for road traffic. Here, we...

journal article 2022

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Qualification of distributed optical fiber sensors using probability of detection curves for delamination in composite laminates

Falcetelli, F. (author), Cristiani, D.L.M. (author), Yue, N. (author), Sbarufatti, Claudio (author), Troiani, Enrico (author), Di Sante, Raffaella (author), Zarouchas, D. (author)

Despite the promising application of Distributed Optical Fiber Sensors (DOFS) in monitoring damage in composite structures, their implementation outside academia is still unsatisfactory due to the lack of a systematic approach to assessing their damage detection performance. The existing tool developed for non-destructive evaluation,...

journal article 2022

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Long-Term Temperature-Dependent Degradation of 175 W Chip-on-Board LED Modules

Herzog, Alexander (author), Wagner, Max (author), Benkner, Simon (author), Zandi, Babak (author), van Driel, W.D. (author), Khanh, Tran Quoc (author)

We report on the degradation dynamics and mechanisms of the commercially available chip-on-board (COB) high-power light-emitting diode (LED) modules with an electrical power of 175 W. Due to the associated thermal load, the temperature dependence of the aging processes is additionally analyzed within the scope of this work. The aging tests...

journal article 2022

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On worst-case correlation length in probabilistic 3D bearing capacity assessments

Li, Yajun (author), Li, Jianguang (author), Xu, Nengxiong (author), Fenton, Gordon A. (author), Vardon, P.J. (author), Hicks, M.A. (author)

Correlation length or scale of fluctuation (SOF) is often used as a primary parameter in defining the spatial correlation characteristics of varying soil properties. However, geotechnical site investigations are rather limited so that proper determination of correlation length is not always possible. The concept of a worst-case correlation...

journal article 2022

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Thermal Cycling in Converter IGBT Modules with Different Cooling Systems in Pitch- and Active Stall-Controlled Tidal Turbines

Wani, F.M. (author), Shipurkar, U. (author), Dong, J. (author), Polinder, H. (author)

This paper compares active and passive cooling systems in tidal turbine power electronic converters. The comparison is based on the lifetime of the IGBT (insulated gate bipolar transistor) power modules, calculated from the accumulated fatigue due to thermal cycling. The lifetime analysis accounts for the influence of site conditions, namely...

journal article 2021

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Incorporating Power Electronic Converters Reliability into Modern Power System Reliability Analysis

Peyghami, S. (author), Blaabjerg, Frede (author), Palensky, P. (author)

This article aims to incorporate the reliability model of power electronic converters into power system reliability analysis. The converter reliability has widely been explored in device- and converter-levels according to physics of failure analysis. However, optimal decision-making for design, planning, operation, and maintenance of power...

journal article 2021

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A Chip Integrity Monitor for Evaluating Moisture/Ion Ingress in mm-Sized Single-Chip Implants

Akgün, O.C. (author), Nanbakhsh, K. (author), Giagka, Vasiliki (author), Serdijn, W.A. (author)

For mm-sized implants incorporating silicon integrated circuits, ensuring lifetime operation of the chip within the corrosive environment of the body still remains a critical challenge. For the chip's packaging, various polymeric and thin ceramic coatings have been reported, demonstrating high biocompatibility and barrier properties. Yet, for...

journal article 2020

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Testing the Validity and Reliability of an Instrument Measuring Engineering Students' Perceptions of Transversal Competency Levels

Leandro Cruz, M. (author), van den Bogaard, M.E.D. (author), Saunders-Smits, Gillian (author), Groen, W.A. (author)

Contribution: This study reports on a reliable and valid instrument that measures engineering students' perceptions of their competency levels. A better understanding of students' needs in engineering curricula will support the development of engineering students' transversal competencies. Background: Prior research has investigated how...

journal article 2020

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Value of information of combinations of proof loading and pore pressure monitoring for flood defences

van der Krogt, M.G. (author), Klerk, W.J. (author), Kanning, W. (author), Schweckendiek, T. (author), Kok, M. (author)

Spatial variability and limited measurements often result in low reliability estimates of geotechnical failure modes of dikes (i.e., earthen flood defences). Required dike reinforcements are usually not executed within a few years after inception, which enables efforts to improve reliability estimates by reducing uncertainty. Often decision...

journal article 2020

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An Overview on the Reliability of Modern Power Electronic Based Power Systems

Peyghami, S. (author), Palensky, P. (author), Blaabjerg, Frede (author)

Renewable energy resources are becoming the dominating element in power systems. Along with de-carbonization, they transform power systems into a more distributed, autonomous, bottom-up style one. We speak of Smart Grid and Microgrid when distributed energy resources take over. While being a means to improve technical and financial efficiency,...

journal article 2020

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Finite element-based reliability assessment of quay walls

Roubos, A.A. (author), Schweckendiek, T. (author), Brinkgreve, R.B.J. (author), Steenbergen, R. D. J. M. (author), Jonkman, Sebastiaan N. (author)

While reliability methods have already been widely adopted in civil engineering, the efficiency and robustness of finite element-based reliability assessments of quay walls are still fairly low. In this paper, the reliability indices of structural and geotechnical failure modes of two real-life quay walls are determined by coupling...

journal article 2020

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Offline Reconfigurability Based Substation Converter Sizing for Hybrid AC-DC Distribution Links

Shekhar, A. (author), Soeiro, Thiago B. (author), Ramirez Elizondo, L.M. (author), Bauer, P. (author)

Hybrid ac-dc distribution systems with multiple parallel operating ac and dc links are being developed to maximize system capacity during (n-1) contingencies. This paper shows that offline reconfigurability between such ac and dc links post-fault clearance allows an additional design flexibility of reducing the required substation converter...

journal article 2020

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If you are late, everyone is late: late passenger arrival and ride-pooling systems' performance

Kucharski, R.M. (author), Fielbaum, Andres (author), Alonso-Mora, J. (author), Cats, O. (author)

Sharing rides in on-demand systems allow passengers to reduce their fares and service providers to increase revenue, though at the cost of adding uncertainty to the system. Notably, the uncertainty of ride-pooling systems stems not only from travel times but also from unique features of sharing, such as the dependency on other passengers'...

journal article 2020

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System-Level Design for Reliability and Maintenance Scheduling in Modern Power Electronic-Based Power Systems

Peyghami, S. (author), Palensky, P. (author), Fotuhi-Firuzabad, Mahmoud (author), Blaabjerg, Frede (author)

Power electronic converters will serve as the fundamental components of modern power systems. However, they may suffer from poorer reliability if not properly designed, consequently affecting the overall performance of power systems. Accordingly, the converter reliability should be taken into account in design and planning of Power Electronic...

journal article 2020

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Material Property Changes in Defects Caused by Reverse Bias Exposure of CIGS Solar Cells

Bakker, N.J. (author), Åhman, Hanna Nilsson (author), Aantjes, Kees (author), Barreau, Nicolas (author), Weeber, A.W. (author), Theelen, Mirjam (author)

Partial shading of Cu(In,Ga)Se₂ modules can lead to the formation of reverse bias induced wormlike defects. These wormlike defects act as local shunts and permanently decrease module output. A good understanding of the formation and propagation mechanisms of these defects is needed in order to mitigate the negative effects, or to...

journal article 2019

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Improving reliability and safety of airborne wind energy systems

Salma, V. (author), Friedl, F. (author), Schmehl, R. (author)

Airborne wind energy systems use tethered flying devices to harvest wind energy beyond the height range accessible to tower-based wind turbines. Current commercial prototypes have reached power ratings of up to several hundred kilowatts, and companies are aiming at long-term operation in relevant environments. As consequence, system...

journal article 2019