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Für eine stärkere Verbindung von Rassismus- und Antisemitismusforschung: Ein Vorschlag zur Übertragung des Konzepts des „institutionellen Rassismus“ auf Antisemitismus
Get PDFA Desaturation-based Short Circuit Protection Technique for Quasi-Two-Level Converters
Get PDFThis paper presents a desaturation-based technique for short-circuit protection in quasi-two-level converters. The proposed design enables a cost-effective implementation of this protection scheme in a flying capacitor multilevel converter operating as a quasi-two-level converter, requiring only two detection circuits for n series-connected switches. Detailed design guidelines for the protection circuit are provided, along with simulations that illustrate its operational boundaries and experimental verification of the proposed scheme
Strongly Inhibited Spontaneous Emission of PbS Quantum Dots Covalently Bound to 3D Silicon Photonic Band Gap Crystals
No full textWe report spontaneous emission from PbS quantum dots covalently bound topolymer brush layers grafted from Si inside 3D photonic band gap crystals. Weobserve broad (26% bandwidth) and up to 30x band-gap inhibition
A decentralized energy management system based on multi-objective optimization
No full textThe global shift to clean energy is transforming how energy is produced and consumed, driven by the need to reduce carbon emissions and reliance on fossil fuels. This transition is accelerating the electrification of sectors such as transportation and heating, increasing the integration of renewable energy sources and stressing the electricity grid due to the mismatch between renewable supply and fluctuating demand. As a result, traditional centralized grids are evolving into decentralized networks with bidirectional energy flows, supported by adaptive management solutions like demand-side management and smart devices.A key development in this transition is the rise of Energy Communities (ECs) and Energy Management Systems (EMSs). ECs allow households, businesses, and institutions to collaborate within local energy systems, while EMSs coordinate resources like solar panels, batteries, and flexible loads. This thesis introduces a decentralized EMS framework designed for future ECs, leveraging multi-objective optimization to efficiently manage distributed energy resources (DERs) and flexible assets. The approach models both physical and cyber layers of energy systems, enabling real-time data exchange and decentralized control.The thesis first presents a Multi-Objective Energy Management System (MOEMS) that uses advanced optimization to balance cost, emissions, and grid stability, with a centralized controller adapting to user preferences. Building on MOEMS, a Decentralized Multi-Objective EMS (DMOEMS) distributes decision-making among local controllers, enhancing scalability and resilience. DMOEMS integrates conflicting objectives, cost, emissions, PV curtailment, self-consumption, congestion, and voltage management, using user-defined weights, with controllers optimizing local assets while the EC controller coordinates aggregated profiles.Simulation studies in real-world settings, including the Aardehuizen community and KEZO research lab, demonstrate the adaptability of MOEMS and DMOEMS. MOEMS achieves up to 22% annual electricity cost savings and 37% CO2 reduction compared to traditional EMSs. DMOEMS further improves CO2 emissions, cost savings, PV curtailment, and computational efficiency, while fostering user engagement and satisfaction. The frameworks enable effective integration of communal assets, mitigating grid congestion and stabilizing voltage profiles
Resonant scattering in low energy electron diffraction:Bi/Ni(111)
Get PDFWe report Low Energy Electron Diffraction (LEED) diffraction patterns measured at energies up to 50 eV for a monolayer thick Bi film on Ni(111). Surprisingly, the intensity versus energy profiles of several from the ten unique (i.e., symmetry-independent) sets of spots show finite but pertinent intensity, each only at a well-defined energy. These are attributed to resonant scattering, involving transient capture in eigenstates of the image potential, followed by (multiple) scattering into the vacuum. By its nature, transient capture occurs closely before the energy crosses the Ewald sphere for each considered channel. These energies are one-to-one connected with the corresponding lattice parameters of the Bi-film with its centered rectangular structure, commensurate along Ni[11–2] and high order commensurate along Ni[-110]. In addition, a couple of more intense regular spots show anomalously high intensity at the low energy side upon crossing the Ewald sphere. This feature is attributed to resonant scattering as well. We claim that so far grossly disregarded resonant scattering is a general phenomenon and should be considered in very low energy LEED-IV structural analysis. The intensity versus energy profile of the (0 2) peak does not show obvious evidence for resonant scattering but instead reveals that the Bi film is built up by long (> 20 nm) and narrow (<< 20 nm), translationally shifted domains, oriented along the [-110] azimuth.</p
Developing of a Digital Twin for Industrial Business Parks: The Ecofactorij
No full textThe concept of Digital Twin (DT) has emerged as a transformative approach in the digitalization of industrial systems. This study focuses on developing a DT for the Ecofactorij industrial microgrid, located in Apeldoorn, Netherlands. The Ecofactorij, with its diverse range of interconnected companies—including logistics, refrigeration, manufacturing, and offices—along with photovoltaic power plants, batteries, charging stations, and heat pumps, presents a complex and dynamic system. These entities are interconnected through a 12kV grid with a contracted capacity of 12MW and are monitored by a SCADA system called ManagedGrid. This project is financially supported by the MOOI Energy Control Bussinespark project and involves collaboration between Sparkling Projects, ManagedGrid, Scholt Energy, Saxion, and the University of Twente
The influence of hepatic arterial blood flow rate on holmium microsphere distribution:an MRI study in perfused porcine livers
Get PDFBackground: Transarterial radioembolisation (TARE) is a treatment for liver malignancies, involving the injection of radioactive microspheres in the hepatic artery (HA). Tumour-to-nontumour uptake varies among patients, possibly influenced by patient-specific blood flow profiles. To examine the impact of HA blood flow rate and high microsphere dosages on microsphere distribution in normal liver parenchyma, ex vivo magnetic resonance imaging (MRI)-guided machine perfusion experiments were conducted in porcine livers. Materials and methods: Porcine livers were subjected to oxygenated normothermic machine perfusion at three HA flow rates (0.02, 0.15, and 0.22 mL/min/g liver tissue; n = 3 per condition). Five fractions of 250 mg nonradioactive 165Ho-loaded microspheres were administered to n = 9 livers, and four additional fractions of 1,000 mg to n = 6 livers. Dynamic contrast-enhanced and Ho-sensitive T2*-weighed MR scans were acquired to extract perfusion rates, fictive dose maps, and homogeneity indices (HI). Results: Microsphere distribution correlated moderately with perfusion rate at low HA flow rate (r = 0.611), and very strongly at higher HA flow rates (r = 0.977 and 0.951 for 0.15 and 0.22 mL/min/g, respectively). Homogeneity increased with increasing flow rates, with HIs ranging from 3.68–4.72 at low, to 2.01–2.66 at medium, and 1.60–2.36 at high HA flow rate. HI decreased with higher microsphere concentrations, though distribution patterns remained unchanged. Conclusion: In our ex vivo model, higher HA flow rates resulted in more homogeneous microsphere distributions. The impact on tumourous tissue needs further investigation to determine whether pre-TARE HA blood flow measurements could improve microsphere distribution predictions. Relevance statement: Mapping of the hepatic arterial blood flow rate before transarterial radioembolisation and adjusting the treatment accordingly may help to improve outcomes for patients with liver cancer. Key Points: Parameters influencing microsphere distribution were studied in MRI-perfused healthy porcine livers. Higher hepatic arterial blood flow rates led to more homogeneous microsphere distributions. Administering large numbers of microspheres did not alter microsphere distribution patterns. Impact on tumour tissue should be further investigated.</p
Strategic bidding in freight transport using deep reinforcement learning
Get PDFThis paper presents a multi-agent reinforcement learning algorithm to represent strategic bidding behavior by carriers and shippers in freight transport markets. We investigate whether feasible market equilibriums arise without central control or communication between agents. Observed behavior in such environments serves as a stepping stone towards self-organizing logistics systems like the Physical Internet, while also offering valuable insights for the design of contemporary transport brokerage platforms. We model an agent-based environment in which shipper and carrier actively learn bidding strategies using policy gradient methods, posing bid- and ask prices at the individual container level. Both agents aim to learn the best response given the expected behavior of the opposing agent. Inspired by financial markets, a neutral broker allocates jobs based on bid-ask spreads. Our game-theoretical analysis and numerical experiments focus on behavioral insights. To evaluate system performance, we measure adherence to Nash equilibria, fairness of reward division and utilization of transport capacity. We observe good performance both in predictable, deterministic settings (∼ 95% adherence to Nash equilibria) and highly stochastic environments (∼ 85% adherence). Risk-seeking behavior may increase an agent’s reward share, yet overly aggressive strategies destabilize the system. The results suggest a potential for full automation and decentralization of freight transport markets. These insights ease the design of real-world market platforms, suggesting an innate tendency of markets to reach equilibria without behavioral models, information sharing or explicit incentives.</p
Smart Devices Require Skilled Users:Home Automation Performance Tests among the Dutch Population
Get PDFThe benefits obtained from home automation are promising and will become more pronounced as smart home technologies continue to develop. To achieve benefits, users require operational, data, and strategic skills to control and automate smart devices, retrieve and understand collected data, and make informed decisions. These skills were tested by providing assignments in a virtual test environment to 100 Dutch adult participants. The assignments were designed to measure different facets of all skills by using the functions, data, and automations of smart home devices. The results suggest that the Dutch adult population is not sufficiently skilled in using the smart home to its full potential; several skills related problems occurred in the tests. Furthermore, in terms of gender, age, and education, home automation further reinforces existing social-digital inequalities. Thus, earlier digital inequalities will remain present for some time, despite increasing device autonomy.</p
A Non-Homogeneous Alternating Renewal Process Model for Interval Censoring
Get PDFPrevious approaches to modelling interval-censored data have often relied on assumptions of homogeneity in the sense that the censoring mechanism, the underlying distribution of occurrence times, or both, are assumed to be time-invariant. In this work, we introduce a model which allows for non-homogeneous behaviour in both cases. In particular, we outline a censoring mechanism based on a non-homogeneous alternating renewal process in which interval generation is assumed to be time-dependent, and we propose a Markov point process model for the underlying occurrence time distribution.We prove the existence of this process and derive the conditional distribution of the occurrence times given the intervals. We provide a framework within which the process can be accurately modelled, and subsequently compare our model to the homogeneous approach through a number of illustrative examples