112 research outputs found
Vth stability and gate leakage current trade-off in p-GaN gate power HEMTs during on- and off-state stress
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Remembering Hadewijch : the travelling memory of a medieval mystical author in modern Belgium
No full textAbstract: \u2018Wees tactvol in gezelschap en vraag niet wie er \ue9\ue9n versregel van Hadewijch memoreeren kan\u2019 [Be tactful in company and don\u2019t ask who is able to remember one line of Hadewijch\u2019s]. In a 1938 newspaper column, a Flemish literary critic bemoaned the fact that the public did not keep the memory of the medieval mystical author Hadewijch (c. 1240) alive by learning her writings by heart. Also Francophone newspapers voiced the opinion that the mystic was \u2018h\ue9las trop peu connue\u2019 [alas too little known]. From her discovery in 1830 onwards until well after editions and anthologies of her works had been printed by major publishing houses, a recurrent trope in the memorial cult developing around the medieval mystic in modern Belgium would be that she and her oeuvre were in urgent and permanent need of being actively \u2018unforgotten\u2019, which was pictured as a collective project that needed to be provided with new fuel at various instances. To this day, Hadewijch\u2019s biography is practically unknown. Most probably, she operated in the mid-thirteenth century in the Duchy of Brabant, where she taught the workings of minne or mystical love to a circle of followers. To that end, she compiled a mystical oeuvre that disappeared from view after the fifteenth century, only to be rediscovered during the 1830 Belgian revolution. Belgian cultural actors with diverse ideological profiles, mother tongues, social backgrounds and confessional outlooks endeavoured to construct a collective memorial cult around the faceless author, shaping an image of her that proved porous to the burning issues of their time. Both hindered and stimulated by Hadewijch\u2019s lack of biography and the opacity of her writings, the mystic\u2019s memory travelled across segments of Belgian society, engendering a wide array of mnemonic practices that flourished in parallel yet at times communicating circuits. Drawing on insights from cultural memory studies and cultural transfer studies, this dissertation investigates why and how Belgian memory-makers attempted to make Hadewijch memorable to the modern-day public. Rather than tracing the linear transmission of a stable figure of memory with predetermined characteristics, it scrutinizes the performative uses that have been made of Hadewijch\u2019s memory in the very process of shaping it. In doing so, it studies how the mystic\u2019s memory travelled across Belgium\u2019s confessional, linguistic, political and social fault lines and, how, after traversing the country\u2019s borders in translation, it returned back \u2018home\u2019 in new guises. In following the \u2018mnemonic routes\u2019 travelled by Hadewijch\u2019s memory in modern Belgium, the dissertation focuses on the multiple transfer strategies developed by cultural mediators in inscribing \u2018their\u2019 Hadewijch(s) in cultural memory. Covering sources ranging from scholarly editions and popularizing publications to sculpture, poetry and encyclopaedias, from newspapers and speeches to the correspondence of academics, town officials and translators, the cases covered in the six chapters provide the first study of Hadewijch\u2019s cultural remembrance in Belgium from the discovery of her oeuvre in 1830 \u2013 when Belgium gained its independence \u2013 to the late 1970s \u2013 when the country rapidly federalized and secularized, which coincided with the gradual detachment of Hadewijch\u2019s memory from the Belgian context. The first two chapters focus on pivotal moments in Hadewijch\u2019s reception. Chapter 1 focuses on the philological confusion Hadewijch\u2019s manuscripts engendered upon her discovery and on the first attempts to interpret, edit and monumentalize them. Chapter 2 turns to the efforts of the philologist Jozef van Mierlo to overwrite nineteenth-century accounts of Hadewijch\u2019s legacy, studying his attempts to have Hadewijch remembered as a \u2018middlebrow\u2019 mystic by a broad Flemish public. The next four chapters examine mnemonic practices that are indebted to the mediating efforts analyzed in the first two chapters. Chapter 3 concentrates on the impact of translation on Hadewijch\u2019s remembrance in Belgium, focusing on the entangled transfer history of the French translation of Hadewijch\u2019s First Vision in Herm\ue8s, a periodical founded by cultural actors with ties to the Brussels-based circle of Surrealists. Chapter 4 studies how Hadewijch was canonized as a stock feature of the memorial universe of the radicalized Flemish Movement, focusing on how she was mobilized as a role model for Flemish Catholic women and girls. Chapter 5 examines the \u2018Reninca case\u2019 which manifested itself in Flemish literary criticism in the late-1940s and early-1950s, a polemic revolving around the question as to whether a certain young female Flemish Catholic poet could be considered as a \u2018new Hadewijch\u2019. Chapter 6 examines the gradual obsolescence of Hadewijch\u2019s memory in Belgium as of the 1960s through the prism of the oeuvre of Suzanne Lilar, a Flemish Francophone author who assigned Hadewijch a central place in her writings. The analysis of the case studies shows that despite its fuzziness, Hadewijch\u2019s memory proved so mobile in Belgium that it was repeatedly re-embodied by (a collective of) bodies living in the present. That was made possible by transferring a set of mnemonic soundbites to new target audiences while varying on how and in which context Hadewijch and her oeuvre were presented: co-texts and paratexts were key to keeping the mystic on the move. Importantly, this study shows that the transfer of Hadewijch\u2019s memory did not follow a unidirectional but an entangled course: the Hadewijch image constructed by the philologist Jozef van Mierlo was incessantly modulated by other mediators, who at times revitalized alternative identifications. Together, the chapters demonstrate that across divergent mnemonic practices, Hadewijch\u2019s memory was formatted according to a narrative template of \u2018reconnection\u2019, in which the malleability of the mystic\u2019s minne, her medieval and supposedly knightly personality and the \u2018mnemotechnology\u2019 of her mystical oeuvre played a central role. Lastly, the dissertation shows that Hadewijch\u2019s memory did not function as a catalyst in the historical developments that marked modern Belgium, but that remembering her nevertheless proved functional against those changing contexts. As a result, studying Hadewijch\u2019s travelling memory grants access to previously hidden zones of transcultural exchange which otherwise would remain unvisited, and reveals a patchwork of porous points of connection between cultural repertoires and mnemonic communities
Complete genome sequence of the Escherichia coli phage Ayreon
No full textWe report the whole-genome sequence of a new Escherichia coli temperate phage, Ayreon, comprising a linear double-stranded DNA (dsDNA) genome of 44,708 bp
Correction to: [18F]mFBG PET‑CT for detection and localisation of neuroblastoma: a prospective pilot study (European Journal of Nuclear Medicine and Molecular Imaging, (2023), 50, 4, (1146-1157), 10.1007/s00259-022-06063-6)
No full textThe article [ 18F]mFBG PET‑CT for detection and localisation of neuroblastoma: a prospective pilot study, written by Atia Samim, Thomas Blom, Alex J. Poot, Albert D. Windhorst, Marta Fiocco, Nelleke Tolboom, Arthur J. A. T. Braat, Sebastiaan L. Meyer Viol, Rob van Rooij, Max M. van Noesel, Marnix G. E. H. Lam, Godelieve A. M. Tytgat, and Bart de Keizer, was originally published Online First without Open Access. After publication in volume 50, issue 4, page 1146 - 1157 the author decided to opt for Open Choice and to make the article an Open Access publication
Interactive wave-structure impacts in aerated water: Numerical modeling of interactive rigid body motion in aerated water wave impacts
No full textMarine structures can sustain damage due to violent wave impacts that are characterized by complex dynamics involving both water and air. Methods that predict impacts loads for structural design often assume the water as incompressible. These predictions can be inaccurate during impacts where air is entrained in water, as that greatly increases its compressibility. Initial impact forces may decrease due to a cushioning effect. However, the total severity of the impact may increase due to temporal spreading and oscillations of impact pressure. Previous research on aerated water impacts covers breaking waves against fixed structures, flat water slamming or green water events, but not the interactive motion of rigid marine structures in free surface waves. This work aims to evaluate the effect of aerated water impacts on the dynamics of floating rigid bodies in irregular waves. As a part of this work, a state-of-the-art numerical simulation method for aerated water impacts is extended with a monolithic coupling for rigid body motion. Additionally, boundary conditions for wave generation were implemented for a validation of the method during breaking wave impact. Results of the verification of both extensions compare well to other literature. It can be concluded from this thesis that the compressibility effects of aeration on penetration depth after cylinder slamming can be neglected for entry Mach numbers below 0.1. For further research, it is recommended that this numerical method is used for a range of experiments with various geometries and higher impact velocities. This could provide more insight into situations where aerated water could have important design implications.It can be concluded from this thesis that the compressibility effects of aeration on penetration depth after cylinder slamming can be neglected for entry Mach numbers below 0.1. For further research, it is recommended that this numerical method is used for a range of experiments with various geometries and higher impact velocities. This could provide more insight into situations where aerated water could have important design implications.It can be concluded from this thesis that the compressibility effects of aeration on penetration depth after cylinder slamming can be neglected for entry Mach numbers below 0.1. For further research, it is recommended that this numerical method is used for a range of experiments with various geometries and higher impact velocities. This could provide more insight into situations where aerated water could have important design implications. It can be concluded from this thesis that the compressibility effects of aeration on penetration depth after cylinder slamming can be neglected for entry Mach numbers below 0.1. For further research, it is recommended that this numerical method is used for a range of experiments with various geometries and higher impact velocities. This could provide more insight into situations where aerated water could have important design implications
Small Scale Methanol Production: Process modelling and design of an autonomous, renewable container sized methanol plant
No full textAt the United Nations Climate Change Conference held in Paris in 2015, ambitious goals for the worldwide CO2 emissions were set. To achieve these goals, a huge reduction in CO2 emissions must be realized. For the energy market, the current aim is to use renewable electricity instead of fossil fuels. However, there are multiple sectors where electricity is not a suitable form of energy, due to storage issues. For example, the chemical industry is heavily based on fossil fuels as a resource to synthesize chemicals. It is therefore useful to investigate the feasibility of renewable synthetic fuels. The goal of this thesis is to design a process that converts the hydrocarbon fuel combustion products CO2 and H2O into a fuel that is a liquid at atmospheric conditions. Methanol is selected as the liquid fuel because of its basic molecule structure. It requires much more energy to obtain methanol from CO2 and H2O than it does from natural gas. The process is determined to be container-sized to become cost competitive through mass production. The technical feasibility of a mass produced, autonomous, renewable and container-sized methanol production plant is studied in this thesis. The whole process is divided into sub processes. H2O is obtained from desalination of seawater. The H2O is split into H2 and O2 using alkaline electrolysis. The CO2 is adsorbed from the air and recovered using pressure and temperature swing. The required energy is obtained using solar PV and solar thermal. The H2 and CO2 are finally converted to methanol in the methanol synthesis sub process. The intermittent character of solar energy yields a dynamically operated process. The methanol synthesis sub process is studied further because of the small scale and dynamic operation that are new concepts for this technology. The other sub processes are considered as black boxes with fixed in- and outputs. The steady state operation of the whole process is modeled using Aspen Plus™ and the distillation process is modelled in MATLAB®. Using the results from Aspen, pinch analysis is performed for optimal use of the available heat. From the results of the model, it is found that an autonomous container-sized methanol production plant is technically feasible. 140 kg of methanol can be produced daily with a purity of at least 96.6 %, using a set-up of three 40 feet sea containers, two of which are dedicated to the capture of CO2. 288 kW of electrical power and 24 kW of heat is required for the operation. This is equal to a solar park with an area of 1663 m2 assuming an average 6 hours of solar irradiance. Using the LHV of methanol in the calculation, the total efficiency of the process is estimated at 45 %. The results from the MATLAB® model of the distillation cannot be validated because the used equation of state of REFPROP underestimates the concentration of methanol in each iteration, yielding an invalid mass balance. Fixing this issue results in an invalid energy balance. It is therefore concluded that REFPROP is not suitable for iterative calculations of distillation columns.Mechanical Engineering | Sustainable Process & Energy Technolog
Exploring trade-offs in on-board versus cloud-based social robots
No full textSocial Robotics is an emerging field in Computer Science. Most social robots currently commercially available to buy do not have fast hardware components. As a result, the built-in software has low accuracy and performance with (amongst others) speech and facial recognition and dialogs during social interaction with users. Cloud computation offers state-of-the-art techniques, performance, and accuracy with its massive available computational power, but at extra costs and increased latency. In this work, we extend and improve a social robot's standard capabilities and performance by making use of cloud computation. This thesis covers an exploration for the trade-offs present when replacing or augmenting built-in robot software with IBM cloud services, based on the humanoid Pepper robot from Softbank.The approach for this exploration was guided by a hospitality use case demonstrated in the offices of two companies: a Dutch Health Insurer and IBM Netherlands. Two products were developed for this single use case based on different development toolboxes. The first toolbox contains all development software from the robot's manufacturer (the NAOqi toolbox), while the second toolbox makes use of cloud services (the Watson Toolbox). Using the product built with the NAOqi toolbox, we evaluate interactions with real users and obtain baseline data and experiences. After evaluating the second product built with the Watson toolbox, we can compare differences in human-robot interaction quality, robot component quality, development methods, and software engineering complexity and Total Costs of Ownership for both products. The main findings include an overview of relevant test metrics and test methods for a social robot's component, including acquired data for some components of the Pepper robot. We show possible architectures for a (semi) cloud-based system, and their trade-offs. Evaluations show that the cloud-based system indeed performs better and has higher human-interaction quality compared to the product built with the NAOqi toolbox, yet downsides such as latency and operating costs are present. This is also reflected in the analysis of single components, where specifically Speech-to-Text from the cloud shows a significant increase in performance and capabilities. We show that a mix of toolboxes results in the best working and cheapest social robot when considering Total Cost of Ownership. IBM Cloud pricing structures and operating costs are analyzed for this. Finally, we contribute to the currently available knowledge on this subject with a decision matrix combining all previously mentioned information in a compact form accessible to people not knowledgeable in the hospitality robot or cloud domains. With the matrix, early-development advice decisions for creating a social robot can be formulated using the data gathered in this thesis.With a broad approach, this research focuses on finding and discussing trade-offs, rather than an in-depth analysis of all components. Providing methods to determine the data as mentioned above, findings, and trade-offs are more important than the actual numbers found in this thesis, as advances in this domain are quick and expected to change often. The end product built using the Watson toolbox is an improvement on multiple levels, yet is still not always able to autonomously and correctly finish all intended interactions. However, its capabilities, performance, and robustness are closer to the level of being used commercially. The techniques we use to extend Pepper's capabilities could be applied to any social robot
3D Scene Compression for Autonomous Driving using Neural Radiance Fields
No full textNeural Radiance Fields (NeRFs) have showcased remarkable effectiveness in capturing complex 3D scenes and synthesizing novel viewpoints. By inherently capturing the entire scene in a compact representation, they offer a promising avenue for applications such as simulators, where efficient storage of real-world data, fast rendering and dynamic generation of new content are crucial. However, the potential for compression in NeRFs has been largely neglected in the existing literature. Moreover, the practical deployment of NeRFs in real-world scenarios, including simulators, faces significant obstacles such as constraints in training time, rendering speed, and scalability to large scenes. While recent advancements have tackled some of these hurdles individually, none have offered a comprehensive solution. In this paper, we introduce a new NeRF architecture based on a textured polygon-based method and augment this architecture by integrating encodings to expedite training. Additionally, we introduce learned pose refinement and an appearance embedding to enhance scalability to larger scenes. Through experimentation on the nuScenes dataset, we demonstrate that our method achieves competitive reconstruction performance with existing techniques while surpassing them in rendering speed. Furthermore, in terms of compression, our findings indicate that our method achieves competitive compression rates comparable to image-based compression techniques, while also enabling novel-view synthesis. This underscores its potential utility in applications like simulators.Mechanical Engineering | Vehicle Engineering | Cognitive Robotic
Simulating smart charging optimization for electric vehicles: A quantification and statistical analysis of the cost reduction and emission reduction potential of an aggregated Dutch EV fleet
No full textThe objective of this research is to understand what smart charging can bring business and society at large. In close collaboration with the largest fleet operator in the world and a commercial aggregator, the impact of smart charging on both cost reduction and carbon reduction was simulated for an electric vehicle (EV) fleet in 2018. The simulation is designed to quantify the cost reduction of EV smart charging in The Netherlands as realistic as possible. Besides cost reduction quantification, the objective is to create a better understanding of what variables influence smart charging cost reduction. This is done via a statistical analysis of the smart charging simulations output. Furthermore, this research also has the objective find the direct impact of smart charging on carbon intensity of the electricity used for personal transport.In this research, an EV aggregators perspective is leading. The EV aggregators could utilizing available flexibility in an EV fleet to deliver flexibility services. The strategy chosen to simulate is based on day ahead market optimization and passive balancing on the imbalance market. The EV fleet is assumed to be an isolated portfolio handled by the balance responsible party (BRP). The average synthetic load profile over 2018 was €41,56 per MWh and this is used as benchmark to quantify the smart charging savings in the simulations. Different smart charging simulation set-up scenarios are designed and executed. In all simulations a real-world charging data set with 300.000 historic charging sessions was used. For each session, a new smart charging profile is determined by the optimization algorithms. The session price and session carbon intensity is calculated for both the smart charging scenarios as the business-as-usual scenarios. To compare the results of the different smart charging set-up scenarios, the average session price of all session in that simulations is used. At the same time, the smart charging savings is calculated based on the defined benchmark. The findings within this thesis support the conclusion that the used smart charging algorithms work properly and could decrease the electricity purchase price in The Netherlands. Additionally we found that the carbon intensity of the charged electricity during the smart charging schedule decreases compared to a business as usual scenario. This is a direct result of a correlation between the carbon intensity in the grid and day ahead prices in The Netherlands. EV aggregators are able to add flexibility to the demand side of the electricity system by means of smart charging, if a strong price incentive is provided. If stakeholders across the mobility and the energy sector work together, a real-world commercial implementation based on the price incentives on day ahead market and imbalance market in The Netherlands is possible. In the statistical analysis, multiple regression models show a linear relation between three independent variables (the session duration, session volume and maximum power of the charge point) and two dependent variables (the average session purchase price and savings per session). The key insights from the models empowered three main recommendations to EV aggregators to optimize the smart charging savings in the future: 1) Encourage longer session length. 2) Encourage regular overnight charging sessions behaviour, independent from the charging needs. 3) Stimulate access to high charging power. The data showed compelling differences between the 20% BEVs and the 80% PHEVs and their results were separated accordingly in this research. In all simulation set-up scenarios are the PHEVs outperforming the BEVs in terms of a lower average session price and higher cost reduction. If the smart charging strategy is executed as proposed in this thesis, the EV aggregator is exposed to the day ahead market and imbalance settlements for its portfolio. The EV aggregator is able to decrease the electricity purchase price, while acting as BRP. The exposure to the markets brings significant risk. Collaboration with an electricity supplier or BRP could potentially increase the smart charging savings for the EV aggregator. Furthermore, other revenue streams to utilize flexibility could be investigated. If stacking different flexibility strategies is possible, it could increase the smart charging value in the future.Electrical Engineering | Sustainable Energy Technolog
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