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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.
41

Advanced Concepts for Automatic Differentiation based on Operator Overloading

Kowarz, Andreas 20 March 2008 (has links)
Mit Hilfe der Technik des Automatischen Differenzierens (AD) lassen sich für Funktionen, die als Programmquellcode gegeben sind, Ableitungsinformationen rechentechnisch effizient und mit geringem Aufwand für den Nutzer bereitstellen. Eine Variante der Implementierung von AD basiert auf der Überladung von Operatoren und Funktionen, die von vielen modernen Programmiersprachen ermöglicht wird. Durch Ausnutzung des Konzepts der Überladung wird eine interne Funktions-Repräsentation (Tape) generiert, die anschließend für die Ableitungsberechnung herangezogen wird. In der Dissertation werden neue Techniken erarbeitet, die eine effizientere Tape-Erstellung und die parallele Tape-Auswertung ermöglichen. Anhand von Laufzeituntersuchungen für numerische Beispiele werden die Möglichkeiten der neuen Techniken verdeutlicht. / Using the technique of Automatic Differentiation (AD), derivative information can be computed efficiently for any function that is given as source code in a supported programming languages. One basic implementation strategy is based on the concept of operator overloading that is available for many programming languages. Due the overloading of operators, an internal representation of the function can be generated at runtime. This so-called tape can then be used for computing derivatives. In the thesis, new techniques are introduced that allow a more efficient tape creation and the parallel evaluation of tapes. Advantages of the new techniques are demonstrated by means of runtime analyses for numerical examples.
42

Simulation of Lower Limb Muscle Activity During Inclined Slope Walking / Simulering av muskelaktivering för nedre extremiteten vid gång i lutning

Arumuganainar, Ganesh Prasanth January 2019 (has links)
Robotic exoskeletons are designed to assist patients with motor dysfunctions. Recent researches focus on extending the robotic assistance to patient activities other than ground level walking. This study aims to analyse the lower limb muscle activity during inclined slope walking contrasting with that of ground level walking. Two different angles of inclination were chosen: 9 degrees and 18 degrees. 9 degrees inclined slope is the universal ramp size for wheelchairs. The hypothesis is that muscle activation, and ultimately metabolic cost, in inclined slope walking is different from that of ground level walking. Collected motion data and simulation in OpenSim prove that the difference in metabolic cost is because of increased activity of ankle dorsiflexors and hip extensors and reduced activity of knee extensors. Finally, muscle activities along with other criteria such as kinematic alignment and joint range of motion are summed up as biomechanical considerations for robotic exoskeleton design.
43

Workflow and Activity Modeling for Monitoring Surgical Procedures / Modélisation des activités chirurgicales et de leur déroulement pour la reconnaissance des étapes opératoires

Padoy, Nicolas 14 April 2010 (has links)
Le bloc opératoire est au coeur des soins délivrés dans l'hôpital. Suite à de nombreux développements techniques et médicaux, il devient équipé de salles opératoires hautement technologiques. Bien que ces changements soient bénéfiques pour le traitement des patients, ils accroissent la complexité du déroulement des opérations. Ils impliquent également la présence de nombreux systèmes électroniques fournissant de l'information sur les processus chirurgicaux. Ce travail s'intéresse au développement de méthodes statistiques permettant de modéliser le déroulement des processus chirurgicaux et d'en reconnaitre les étapes, en utilisant des signaux présents dans le bloc opératoire. Nous introduisons et formalisons le problème consistant à reconnaitre les phases réalisées au sein d'un processus chirurgical, en utilisant une représentation des chirurgies par une suite temporelle et multi-dimensionnelle de signaux synchronisés. Nous proposons ensuite des méthodes pour la modélisation, la segmentation hors-ligne et la reconnaissance en-ligne des phases chirurgicales. La méthode principale, une variante de modèle de Markov caché étendue par des variables de probabilités de phases, est démontrée sur deux applications médicales. La première concerne les interventions endoscopiques, la cholécystectomie étant prise en exemple. Les phases endoscopiques sont reconnues en utilisant des signaux indiquant l'utilisation des instruments et enregistrés lors de chirurgies réelles. La deuxième application concerne la reconnaissance des activités génériques d'une salle opératoire. Dans ce cas, la reconnaissance utilise de l'information 4D provenant d'un système de reconstruction multi-vues / The department of surgery is the core unit of the patient care system within a hospital. Due to continuous technical and medical developments, such departments are equipped with increasingly high-tech surgery rooms. This provides higher benefits for patient treatment, but also increases the complexity of the procedures' workflow. This also induces the presence of multiple electronic systems providing rich and various information about the surgical processes. The focus of this work is the development of statistical methods that permit the modeling and monitoring of surgical processes, based on signals available in the surgery room. We introduce and formalize the problem of recognizing phases within a workflow, using a representation of interventions in terms of multidimensional time-series formed by synchronized signals acquired over time. We then propose methods for the modeling, offline segmentation and on-line recognition of surgical phases. The main method, a variant of hidden Markov models augmented by phase probability variables, is demonstrated on two medical applications. The first one is the monitoring of endoscopic interventions, using cholecystectomy as illustrative surgery. Phases are recognized using signals indicating tool usage and recorded from real procedures. The second application is the monitoring of a generic surgery room workflow. In this case, phase recognition is performed by using 4D information from surgeries performed in a mock-up operating room in presence of a multi-view reconstruction system
44

Zadejte název práce Finanční analýza společnosti Pragometal / Financial analysis of Pragometal s.r.o.

Svoboda, Adam January 2009 (has links)
Without a doubt we can say that financial analysis is basic knowledge of every financial manager. Its principle is not only in description of company's past activities, but also in future predictions, planning and decision making. That is absulutly necessery in todays world with its dayly changes. Financial analysis outputs may be considered as basic pillar of managing, planning, future strategies making, but also for a intercompany comparison and activity analysis. Analysed company, called Pragometal is a metall scrap wholesale business (CZ-NACE 467700). It is a limited liability company. Its assets peak was over 75 million crowns and its highest profit after tex reached over 7 mil. CZK. Financial analysis deals with the time period since 2004 till 2008. I have decided to analyse this company, because I am one of its employees in administration and I have a knowledge a view of its activities. I also get some internal information, that are necessery for higher quality of financial analysis.
45

GIS-based Episode Reconstruction Using GPS Data for Activity Analysis and Route Choice Modeling / GIS-based Episode Reconstruction Using GPS Data

Dalumpines, Ron 26 September 2014 (has links)
Most transportation problems arise from individual travel decisions. In response, transportation researchers had been studying individual travel behavior – a growing trend that requires activity data at individual level. Global positioning systems (GPS) and geographical information systems (GIS) have been used to capture and process individual activity data, from determining activity locations to mapping routes to these locations. Potential applications of GPS data seem limitless but our tools and methods to make these data usable lags behind. In response to this need, this dissertation presents a GIS-based toolkit to automatically extract activity episodes from GPS data and derive information related to these episodes from additional data (e.g., road network, land use). The major emphasis of this dissertation is the development of a toolkit for extracting information associated with movements of individuals from GPS data. To be effective, the toolkit has been developed around three design principles: transferability, modularity, and scalability. Two substantive chapters focus on selected components of the toolkit (map-matching, mode detection); another for the entire toolkit. Final substantive chapter demonstrates the toolkit’s potential by comparing route choice models of work and shop trips using inputs generated by the toolkit. There are several tools and methods that capitalize on GPS data, developed within different problem domains. This dissertation contributes to that repository of tools and methods by presenting a suite of tools that can extract all possible information that can be derived from GPS data. Unlike existing tools cited in the transportation literature, the toolkit has been designed to be complete (covers preprocessing up to extracting route attributes), and can work with GPS data alone or in combination with additional data. Moreover, this dissertation contributes to our understanding of route choice decisions for work and shop trips by looking into the combined effects of route attributes and individual characteristics. / Dissertation / Doctor of Philosophy (PhD)

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