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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
201

Verbesserung und Evaluation eines Modell-Ensembles für die Vorhersage von Unfalldaten anhand synthetischer Daten

Chen, Haoyuan 09 November 2021 (has links)
Ziel dieser Arbeit ist es, robuste und performante Algorithmen für die Fusion von polizeilichen Unfalldaten zur Testszenariengenerierung im Rahmen der Absicherung automatisierter Fahrfunktionen zu generieren. In dieser Arbeit werden dabei Methoden zur Datenfusion in Kombination mit generativen und Klassifikationsmodellen untersucht. Eine spezifische Variable vom Empfänger wird während des Datenfusionsverfahrens im Voraus entfernt. Ein Spender mit den gemeinsamen Variablen wird verwendet, um die Vorhersage für die fehlende spezifische Variable im Empfänger zu erhalten. Als Methode werden Ensembles aus Distance-Hot-Deck und Machine-Learning Verfahren für die Vorhersage verwendet. Nach der Vorhersage werden die Ergebnisse anhand ausgewählter Bewertungsmetriken bewertet. Darüber hinaus werden zwei generative Modelle eingeführt, um Datensätze unterschiedlicher Qualität zu synthetisieren. Ziel ist es, die Robustheit der Ensembles mit den synthetisierten „Rauschdaten“ zu testen und die Performance von Ensembles mit den synthetisierten Daten hoher Qualität zu verbessern. Schließlich können Erkenntnisse darüber gewonnen werden, welche Ensembles die besten Ergebnisse für die Datenfusion liefern.:1. Einleitung 2. Grundlagen 3. Randbedingungen 4. Vorgehensweise 5. Ergebnisse 6. Diskussion & Ausblick
202

The curious case of artificial intelligence : An analysis of the relationship between the EU medical device regulations and algorithmic decision systems used within the medical domain

Björklund, Pernilla January 2021 (has links)
The healthcare sector has become a key area for the development and application of new technology and, not least, Artificial Intelligence (AI). New reports are constantly being published about how this algorithm-based technology supports or performs various medical tasks. These illustrates the rapid development of AI that is taking place within healthcare and how algorithms are increasingly involved in systems and medical devices designed to support medical decision-making.  The digital revolution and the advancement of AI technologies represent a step change in the way healthcare may be delivered, medical services coordinated and well-being supported. It could allow for easier and faster communication, earlier and more accurate diagnosing and better healthcare at lower costs. However, systems and devices relying on AI differs significantly from other, traditional, medical devices. AI algorithms are – by nature – complex and partly unpredictable. Additionally, varying levels of opacity has made it hard, sometimes impossible, to interpret and explain recommendations or decisions made by or with support from algorithmic decision systems. These characteristics of AI technology raise important technological, practical, ethical and regulatory issues. The objective of this thesis is to analyse the relationship between the EU regulation on medical devices (MDR) and algorithmic decision systems (ADS) used within the medical domain. The principal question is whether the MDR is enough to guarantee safe and robust ADS within the European healthcare sector or if complementary (or completely different) regulation is necessary. In essence, it will be argued that (i) while ADS are heavily reliant on the quality and representativeness of underlying datasets, there are no requirements with regard to the quality or composition of these datasets in the MDR, (ii) while it is believed that ADS will lead to historically unprecedented changes in healthcare , the regulation lacks guidance on how to manage novel risks and hazards, unique to ADS, and that (iii) as increasingly autonomous systems continue to challenge the existing perceptions of how safety and performance is best maintained, new mechanisms (for transparency, human control and accountability) must be incorporated in the systems. It will also be found that the ability of ADS to change after market certification, will eventually necessitate radical changes in the current regulation and a new regulatory paradigm might be needed.
203

A quasi-Hopf structure in marginally deformed N=4 Super Yang-Mills Theory

Dlamini, Siphesihle Hector January 2020 (has links)
The N= 4 Super Yang-Mills theory in four dimensions admits deformations and the exactly marginal deformations of its SU(3) R-symmetry sub-sector are known as Leigh-Strassler. Leigh-Strassler deformations break the N= 4 supersymmetry down to N= 1 while preserving conformal symmetry. With exactly marginal deformations only the F-terms are deformed thus Leigh-Strassler deformations only affect the superpotential in the Lagrangian. In this thesis we study the symmetry of the marginally deformed N= 4 SYM and demonstrate that its algebraic structure can be understood in terms of quasi-Hopf algebras. Quasi-Hopf algebras have a notion of twisting due to Drinfeld which makes them a natural mathematical language with which to treat deformations. Furthermore the deformation of the N= 4 SYM superpotential is automated by the definition of a suitable star product. / Thesis (PhD)--University of Pretoria, 2020. / NiTheP / Physics / PhD / Unrestricted
204

Domain wall solutions in the AdS/CFT correspondence

Mateos González, Eduardo January 2020 (has links)
In this thesis we study a particular realization of the Domain wall/Quantum Field Theory correspondence, a modification of the Anti de-Sitter/Conformal Field Theory correspondence that is used to study deformations of a Conformal Field Theory. In theQuantum gravity side of the duality we analyze a N = 1 gauged supergravity theory in 7 dimensions which presents two different Anti de-Sitter vacua, one of which preserves the full supersymmetry and one that breaks half of the supercharges. We will find a scalar 1/2-BPS solitonic solution describing a domain wall in an asymptotically Anti de-Sitter spacetime which interpolates between the supersymmetric AdS vacuum and a divergent AdS space situated at infinity, and we will calculate its tension and the effective mass of the scalar field when evaluated at the AdS vacuum. The dual theory of our gauged  supergravity is the 6-dimensional N = (1,0) Superconformal Field Theory, and the scalar 1/2-BPS field is dual to two relevant operators that induce a relevant deformation of the SCFT which can be identified with a renormalization group-flow. Here we will first compute the scaling dimension and the one-point functions of these operators in the SCFT, as well as indicating how to compute the two-point and three-point functions, and then we will study the c-function along the renormalization group-flow they induce and the beta function that characterizes this flow in order to derive some properties of the resulting Quantum Field Theory.
205

Entwicklungsbegleitung als therapeutische Intervention bei ADHS

Wohnhas-Baggerd, Udo 30 November 2004 (has links)
In der vorliegenden Arbeit wird die ADHS-Problematik in Theorie und Praxis aufgezeigt. Der Stand der Forschung, sowie die gängigen Therapiekonzepte werden vorgestellt. Es wird aufgezeigt, dass die unterschiedlichen Sichtweisen und Therapieansätze aus den verschiedenen Disziplinen zu keinem befriedigenden Ergebnis geführt haben. Indem der Autor aus den beteiligten Disziplinen (Medizin, Pädagogik, Psychologie, Motologie und den Überschneidungsbereichen) gegenüberstellt, sollen Gemeinsamkeiten, Unterschiede und wechselseitige Bedingtheiten hervorgehoben werden. In der Überprüfung der Thesen an den bisherigen Untersuchungen und der Diskussion wird ein neues Erklärungsmodell entwickelt. Hierbei wird herausgestellt, dass durch einen systemischen Ansatz das Verständnis des ADHS deutlicher wird. Dieses Modell geht von einer systemischen Sichtweise des Menschen aus. Es basiert auf einem weiterentwickelten motologischen Ansatz und bezieht traditionelle Ansätze aus den unterschiedlichen Disziplinen mit ein. In diesem Modell wird der bisherige Therapiebegriff durch den Begriff Entwicklungsbegleitung ersetzt. An vier Fallbeispielen, die in einer zehnjährigen Forschungspraxis entstanden sind, wird dieser Ansatz in der therapeutischen Praxis überprüft.
206

High Performance GNRFET Devices for High-Speed Low-Power Analog and Digital Applications

Patnala, Mounica 05 1900 (has links)
Indiana University-Purdue University Indianapolis (IUPUI) / Recent ULSI (ultra large scale integration) technology emphasizes small size devices, featuring low power and high switching speed. Moore's law has been followed successfully in scaling down the silicon device in order to enhance the level of integration with high performances until conventional devices failed to cop up with further scaling due to limitations with ballistic effects, and challenges with accommodating dopant fluctuation, mobility degradation, among other device parameters. Recently, Graphene based devices o ered alternative approach, featuring small size and high performances. This includes high carrier mobility, high carrier density, high robustness, and high thermal conductivity. These unique characteristics made the Graphene devices attractive for high speed electronic architectures. In this research, Graphene devices were integrated into applications with analog, digital, and mixed signals based systems. Graphene devices were briefly explored in electronics applications since its first model developed by the University of Illinois, Champaign in 2013. This study emphasizes the validation of the model in various applications with analog, digital, and mixed signals. At the analog level, the model was used for voltage and power amplifiers; classes A, B, and AB. At the digital level, the device model was validated within the universal gates, adders, multipliers, subtractors, multiplexers, demultiplexers, encoders, and comparators. The study was also extended to include Graphene devices for serializers, the digital systems incorporated into the data structure storage. At the mixed signal level, the device model was validated for the DACs/ADCs. In all components, the features of the new devices were emphasized as compared with the existing silicon technology. The system functionality and dynamic performances were also elaborated. The study also covered the linearity characteristics of the devices within full input range operation. GNRFETs with a minimum channel length of 10nm and an input voltage 0.7V were considered in the study. An electronic design platform ADS (Advanced Design Systems) was used in the simulations. The power amplifiers showed noise figure as low as 0.064dbs for class A, and 0.32 dbs for class B, and 0.69 dbs for class AB power amplifiers. The design was stable and as high as 5.12 for class A, 1.02 for class B, and 1.014 for class AB. The stability factor was estimated at 2GHz operation. The harmonics were as low as -100 dbs for class A, -60 dbs for class B, and -50dbs for class AB, all simulated at 1GHz. The device was incorporated into ADC system, and as low as 24.5 micro Watt power consumption and 40 nsec rise time were observed. Likewise, the DAC showed low power consumption as of 4.51 micro Watt. The serializer showed as minimum power consumption of the order of 0.4mW. These results showed that these nanoscale devices have potential future for high-speed communication systems, medical devices, computer architecture and dynamic Nano electromechanical (NEMS) which provides ultra-level of integration, incorporating embedded and IoT devices supporting this technology. Results of analog and digital components showed superiority over other silicon transistor technologies in their ultra-low power consumption and high switching speed.
207

Automated Traffic Control for Smart Landing Facilities

Florin, Charles Henri 30 December 2002 (has links)
The Small Aircraft Transportation System (SATS) is a partnership between the FAA, the NASA, US aviation companies, universities and state and local aviation officials. The purpose of SATS is to develop a system to handle future increase in Air Traffic, reduce time-travel, develop automation in Air Traffic Control (ATC) and make better use of small aircraft and underused airports. The Smart Landing Facility (SLF) is an important part of the program. The SLF is a small airport upgraded with equipment to support SATS aircraft. Among the SLF equipment, SATS needs new detection equipment, and eventually automation. This thesis investigates different techniques to avoid data collision in aircraft radar responses, and to reduce delays between landings and take offs. First, the paper shows how and when the radar receiver can separate two overlapped radar responses. Second, to avoid transponders responses overlapping, requirements in terms of aircraft safety distance are computed, different conflicts in air traffic around the SLF are examined and a solution is proposed for each case. And finally, the thesis investigates how far SATS can go in developing an automatic ATC system and what the role of future human operator will be in ATC. / Master of Science
208

Integrable deformations of principal chiral models and the AdS/CFT correspondence / 主カイラル模型の可積分変形とAdS/CFT対応

Kawaguchi, Io 24 March 2014 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18066号 / 理博第3944号 / 新制||理||1568(附属図書館) / 30924 / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 川合 光, 教授 國廣 悌二, 教授 畑 浩之 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
209

Scrambling and Complexity in AdS/CFT and Black Holes / AdS/CFT対応とブラックホールにおけるスクランブリングと計算複雑度

Watanabe, Kento 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第20916号 / 理博第4368号 / 新制||理||1627(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 高柳 匡, 教授 川合 光, 教授 杉本 茂樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM
210

Quantum Gravity Beyond the End of the World / 世界の終わりを越える量子重力

Wei, Zixia 23 March 2023 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第24403号 / 理博第4902号 / 新制||理||1700(附属図書館) / 京都大学大学院理学研究科物理学・宇宙物理学専攻 / (主査)教授 高柳 匡, 教授 杉本 茂樹, 教授 橋本 幸士 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

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