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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.
21

Theorie und Methodik der Statistik

Huschens, Stefan 30 March 2017 (has links) (PDF)
Das vorliegende Skript ist aus dem Lehrveranstaltungszyklus Theorie und Methodik der Statistik hervorgegangen, den ich an der Fakultät Wirtschaftswissenschaften der TU Dresden im Hauptstudium der Diplomstudiengänge und in den Masterstudiengängen gehalten habe. Es gibt 16 ältere Auflagen, die während mehr als 15 Jahren kontinuierlich überarbeitet, erweitert und korrigiert wurden. Für Hinweise auf Fehler und für Erweiterungs- und Verbesserungsvorschläge danke ich mehreren Studenten und allen Mitarbeitern, die in dieser Zeit am Lehrstuhl für Quantitative Verfahren, insbesondere Statistik beschäftigt waren. Die 30 Kapitel verteilen sich auf die fünf Teile Grundlagen, Schätzen und Testen, Korrelation und Regression, Stochastische Prozesse und Multivariate Verfahren, die jeweils Grundlage einer Lehrveranstaltung waren. Viele Kapitel haben einen abschließenden Abschnitt "Weiterführendes" mit zusätzlichem und ergänzendem Material, das in der Vorlesung nicht behandelt wurde, sowie zusätzlichen Eräauterungen, Beispielen und Anmerkungen. Zur verwendeten Notation und zu mathematischen Grundlagen siehe Anhang A.
22

Video See-Through Augmented Reality Application on a Mobile Computing Platform Using Position Based Visual POSE Estimation

Fischer, Daniel 22 August 2013 (has links)
A technique for real time object tracking in a mobile computing environment and its application to video see-through Augmented Reality (AR) has been designed, verified through simulation, and implemented and validated on a mobile computing device. Using position based visual position and orientation (POSE) methods and the Extended Kalman Filter (EKF), it is shown how this technique lends itself to be flexible to tracking multiple objects and multiple object models using a single monocular camera on different mobile computing devices. Using the monocular camera of the mobile computing device, feature points of the object(s) are located through image processing on the display. The relative position and orientation between the device and the object(s) is determined recursively by an EKF process. Once the relative position and orientation is determined for each object, three dimensional AR image(s) are rendered onto the display as if the device is looking at the virtual object(s) in the real world. This application and the framework presented could be used in the future to overlay additional informational onto displays in mobile computing devices. Example applications include robotic aided surgery where animations could be overlaid to assist the surgeon, in training applications that could aid in operation of equipment or in search and rescue operations where critical information such as floor plans and directions could be virtually placed onto the display. Current approaches in the field of real time object tracking are discussed along with the methods used for video see-through AR applications on mobile computing devices. The mathematical framework for the real time object tracking and video see-through AR rendering is discussed in detail along with some consideration to extension to the handling of multiple AR objects. A physical implementation for a mobile computing device is proposed detailing the algorithmic approach along with design decisions. The real time object tracking and video see-through AR system proposed is verified through simulation and details around the accuracy, robustness, constraints, and an extension to multiple object tracking are presented. The system is then validated using a ground truth measurement system and the accuracy, robustness, and its limitations are reviewed. A detailed validation analysis is also presented showing the feasibility of extending this approach to multiple objects. Finally conclusions from this research are presented based on the findings of this work and further areas of study are proposed.
23

Video See-Through Augmented Reality Application on a Mobile Computing Platform Using Position Based Visual POSE Estimation

Fischer, Daniel 22 August 2013 (has links)
A technique for real time object tracking in a mobile computing environment and its application to video see-through Augmented Reality (AR) has been designed, verified through simulation, and implemented and validated on a mobile computing device. Using position based visual position and orientation (POSE) methods and the Extended Kalman Filter (EKF), it is shown how this technique lends itself to be flexible to tracking multiple objects and multiple object models using a single monocular camera on different mobile computing devices. Using the monocular camera of the mobile computing device, feature points of the object(s) are located through image processing on the display. The relative position and orientation between the device and the object(s) is determined recursively by an EKF process. Once the relative position and orientation is determined for each object, three dimensional AR image(s) are rendered onto the display as if the device is looking at the virtual object(s) in the real world. This application and the framework presented could be used in the future to overlay additional informational onto displays in mobile computing devices. Example applications include robotic aided surgery where animations could be overlaid to assist the surgeon, in training applications that could aid in operation of equipment or in search and rescue operations where critical information such as floor plans and directions could be virtually placed onto the display. Current approaches in the field of real time object tracking are discussed along with the methods used for video see-through AR applications on mobile computing devices. The mathematical framework for the real time object tracking and video see-through AR rendering is discussed in detail along with some consideration to extension to the handling of multiple AR objects. A physical implementation for a mobile computing device is proposed detailing the algorithmic approach along with design decisions. The real time object tracking and video see-through AR system proposed is verified through simulation and details around the accuracy, robustness, constraints, and an extension to multiple object tracking are presented. The system is then validated using a ground truth measurement system and the accuracy, robustness, and its limitations are reviewed. A detailed validation analysis is also presented showing the feasibility of extending this approach to multiple objects. Finally conclusions from this research are presented based on the findings of this work and further areas of study are proposed.
24

Models of neurodegeneration using computational approaches

Khabirova, Eleonora January 2016 (has links)
Alzheimer's disease (AD), as one of the most common neurodegenerative diseases, is characterized by the loss of neuronal dysfunction and death resulting in progressive cognitive impairment. The main histopathological hallmark of AD is the accumulation and deposition of misfolded Aβ peptide as amyloid plaques, however the precise role of Aβ toxicity in the disease pathogenesis is still unclear. Moreover, at early stages of the disease the important clinical features of the disorder, in addition to memory loss, are the disruptions of circadian rhythms and spatial disorientation. In the present work I first studied the role of Aβ toxicity by comparing the findings of genome-wide association studies in sporadic AD with the results of an RNAi screen in a transgenic C. elegans model of Aβ toxicity. The initial finding was that none of the human orthologues of these worm genes are associated with risk for sporadic Alzheimer’s disease, indicating that Aβ toxicity in the worm model may not be equivalent to sporadic AD. Nevertheless, comparing the first degree physical interactors (+1 interactome) of the GWAS and worm screen-derived gene products have uncovered 4 worm genes that have a +1 interactome overlap with the GWAS genes that is larger than one would expect by chance. Three of these genes form a chaperonin complex and the fourth gene codes for actin, a major substrate of the same chaperonin. Next I have evaluated the circadian disruptions in AD by developing a new system to simultaneously monitor the oscillations of the peripheral molecular clock and behavioural rhythms in single Drosophila. Experiments were undertaken on wild- type and Aβ-expressing flies. The results indicate the robustness of the peripheral clock is not correlated with the robustness of the circadian sleep and locomotor behaviours, indicating that the molecular clock does not directly drive behaviour. This is despite period length correlations that indicate that the underlying molecular mechanisms that generate both molecular and behavioural rhythms are the same. Rhythmicity in Aβ-expressing flies is worse than in controls. I further investigated the mechanism of spatial orientation in Drosophila. It was established that in the absence of visual stimuli the flies use self-motion cues to orientate themselves within the tubes and that in a Drosophila model of Aβ toxicity this control function is disrupted.
25

Metody pro odhady náročnosti pracnosti při plánování projektů / Methods for cost estimation in the planning of projects

Pokorný, Martin January 2008 (has links)
This work is focused on the problem of IS/ICT project cost estimation. Main aim of this work is to design a methodology, which can be use for project cost estimation in the initial part of the project stadium. Defining a basic terms of the project management and describing the most widely use cost estimation metods are the first step to archive main aim. This will be achived by studing literature and relevant articles of the project management. Next step is find an appropriate factors which help to set up the methodology. This factors can derive from a stakeholder's analysis. After definition these factors there si possible to set up a particular methodology. Universality (for a wide group of the projects), accuracy (to determine a particular method) and usability (in the initial part of the project stadium) are the most important criteria to review this methodology. Finally, it is necessary to evaluate the proposed methodology. This can be achieved by comparing the methods recommended in the methodology and the methods actually used for the real project cost estimation. The expected benefits of this work are the most widely use cost estimation metods arrangement and creation of the recommended metodology which can be used to cost estimation of future projects.
26

Evaluation environnementale des systèmes agricoles urbains en Afrique de l'Ouest : Implications de la diversité des pratiques et de la variabilité des émissions d'azote dans l'Analyse du Cycle de Vie de la tomate au Bénin / Environmental assessment of urban agricultural systems in West Africa : Implications of the diversity of practices and the variability of nitrogen emissions for the Life Cycle Assessment of tomato from Benin

Perrin, Aurélie 20 December 2013 (has links)
L’agriculture urbaine représente une opportunité de réduire la pauvreté et d’améliorer la sécurité alimentaire des habitants des villes d’Afrique de l’Ouest. L’objectif général de cette thèse est de produire des données d’inventaire représentatives ainsi qu’une évaluation environnementale robuste de ces systèmes de production par la méthodologie Analyse du Cycle de Vie (ACV). Notre cas d’étude a été la tomate des jardins urbains au Bénin. Notre état de l’art nous a permis d’identifier que prendre en compte la diversité des systèmes de production et la variabilité des émissions au champ étaient deux enjeux majeurs de l’ACV des produits maraîchers. Nous avons donc développé un protocole de collecte de données basé sur la typologie qui prend en compte la diversité des systèmes puis mis au point une méthode d’estimation des flux d’azote au champ combinant un bilan d’azote et l’usage d’un modèle biophysique. Nous avons ainsi créé des inventaires pour 6 types de systèmes et une moyenne pondérée représentative de la population étudiée. L’analyse des performances agronomiques de ces systèmes a montré une forte variabilité des rendements et une utilisation fluctuante et souvent excessive d’engrais et de pesticides. L’exploration de la variabilité des flux d’azote à l’échelle de la parcelle et du cycle de culture a permis l’identification de 4 facteurs majeurs: les volumes d’eau d’irrigation, la dose d’azote, le pH du sol et la capacité au champ. A l’aide de scénarios favorables et défavorables aux émissions pour chacun de ces 4 facteurs, nous avons montré que leurs effets sur les résultats d’ACV étaient importants. L’intégration de ces données dans une ACV finalisée a montré qu’un hectare de production de tomate au Bénin était plus impactant que les productions maraichères Européennes. Les avantages du climat favorable du sud Bénin à la production de tomate en contre saison sont annulés par les faibles performances des systèmes d’irrigation, l’usage fréquent d’insecticides et d’importantes émissions azotées. Des données mesurées et des connaissances nouvelles sont nécessaires sur ces systèmes pour valider et affiner nos conclusions. / Urban agriculture provides opportunities to reduce poverty and ensure food safety for cities inhabitants in West Africa. The general objective of this thesis is producing representative inventories and a robust environmental assessment for those production systems using the Life Cycle Assessment (LCA) methodology. Our case study was the tomato production in urban gardens in Benin. Our state of the art identified the integration of the diversity of systems and the variability of field emissions as two major challenges for the LCA of vegetable products. We therefore developed a typology-based protocol to collect cropping systems data that includes their diversity and an approach combining a nitrogen budget and the use of a biophysical model to estimate nitrogen field emissions. We created inventories for 6 cropping system types and one weighted mean representative for the urban tomato growers in Benin. The analysis of the agronomical performances of these systems highlighted the important yield variability and the variable and often excessive use of pesticides and fertilizers. The investigation of nitrogen fluxes variability at plot and crop cycle scales led to the identification of 4 major influencing factors: water use, nitrogen input, soil pH and field capacity. Using favorable and unfavorable scenarios for nitrogen emissions for each of these 4 factors, we demonstrated that the LCA results were sensitive to their variations. The implementation of LCA using those contrasted data showed that one hectare of tomato production in Benin was more impacting than European vegetable productions. The benefits from the favorable climate for producing out-of-season tomatoes were hampered by the low efficiency of irrigations systems, the frequent use of insecticides and large nitrogen emissions. Measured data and new knowledge on these systems are needed to validate and refine our conclusions.
27

Approche EM pour modèles multi-blocs à facteurs à une équation structurelle / EM estimation of a structural equation model

Tami, Myriam 12 July 2016 (has links)
Les modèles d'équations structurelles à variables latentes permettent de modéliser des relations entre des variables observables et non observables. Les deux paradigmes actuels d'estimation de ces modèles sont les méthodes de moindres carrés partiels sur composantes et l'analyse de la structure de covariance. Dans ce travail, après avoir décrit les deux principales méthodes d'estimation que sont PLS et LISREL, nous proposons une approche d'estimation fondée sur la maximisation par algorithme EM de la vraisemblance globale d'un modèle à facteurs latents et à une équation structurelle. Nous en étudions les performances sur des données simulées et nous montrons, via une application sur des données réelles environnementales, comment construire pratiquement un modèle et en évaluer la qualité. Enfin, nous appliquons l'approche développée dans le contexte d'un essai clinique en cancérologie pour l'étude de données longitudinales de qualité de vie. Nous montrons que par la réduction efficace de la dimension des données, l'approche EM simplifie l'analyse longitudinale de la qualité de vie en évitant les tests multiples. Ainsi, elle contribue à faciliter l'évaluation du bénéfice clinique d'un traitement. / Structural equation models enable the modeling of interactions between observed variables and latent ones. The two leading estimation methods are partial least squares on components and covariance-structure analysis. In this work, we first describe the PLS and LISREL methods and, then, we propose an estimation method using the EM algorithm in order to maximize the likelihood of a structural equation model with latent factors. Through a simulation study, we investigate how fast and accurate the method is, and thanks to an application to real environmental data, we show how one can handly construct a model or evaluate its quality. Finally, in the context of oncology, we apply the EM approach on health-related quality-of-life data. We show that it simplifies the longitudinal analysis of quality-of-life and helps evaluating the clinical benefit of a treatment.
28

Vytvoření aplikace pro získání modálních parametrů při experimentální modální analýze / Creation of Modal Parameter Estimation Application for Experimental Modal Analysis

Ondra, Václav January 2014 (has links)
The aim of this diploma thesis is a creation of modal parameter estimation application. Modal properties (natural frequencies, damping factors and mode shapes) are used in many dynamics analysis and their accurate determination is very important therefore the modal parameter estimation is one of the most significant part of the experimental modal analysis. Many methods have been developed for modal parameter estimation, each of them with different assumptions and with different accuracy. In the beginning of this thesis, a theory connected with modal analysis and a theory which is necessary for understanding to presented modal parameter methods are given. Then four different modal parameter estimation methods are presented - Peak Picking, Circle Fit, Least Square method and Eigensystem Realization Algorithm. The application for the modal parameter estimation is the output of this diploma thesis. In addition, the application allows performing all experimental modal analysis such as estimation of frequency response functions, animation of the found mode shapes, different kinds of comparison etc. In the conclusion, three structures are shown on which the application and modal parameter estimation methods were tested.
29

Theorie und Methodik der Statistik

Huschens, Stefan 30 March 2017 (has links)
Das vorliegende Skript ist aus dem Lehrveranstaltungszyklus Theorie und Methodik der Statistik hervorgegangen, den ich an der Fakultät Wirtschaftswissenschaften der TU Dresden im Hauptstudium der Diplomstudiengänge und in den Masterstudiengängen gehalten habe. Es gibt 16 ältere Auflagen, die während mehr als 15 Jahren kontinuierlich überarbeitet, erweitert und korrigiert wurden. Für Hinweise auf Fehler und für Erweiterungs- und Verbesserungsvorschläge danke ich mehreren Studenten und allen Mitarbeitern, die in dieser Zeit am Lehrstuhl für Quantitative Verfahren, insbesondere Statistik beschäftigt waren. Die 30 Kapitel verteilen sich auf die fünf Teile Grundlagen, Schätzen und Testen, Korrelation und Regression, Stochastische Prozesse und Multivariate Verfahren, die jeweils Grundlage einer Lehrveranstaltung waren. Viele Kapitel haben einen abschließenden Abschnitt "Weiterführendes" mit zusätzlichem und ergänzendem Material, das in der Vorlesung nicht behandelt wurde, sowie zusätzlichen Eräauterungen, Beispielen und Anmerkungen. Zur verwendeten Notation und zu mathematischen Grundlagen siehe Anhang A.
30

Political Parties on the Move: Computational Scaling Method Applied to Swedish Parliamentary Debates / Politiska Partier i Rörelse: Datorbaserad Skalningsmetod Applicerad på Svenska Riksdagsdebatter

Källström Ståhlgren, Carl-Oscar January 2022 (has links)
Over the years, a variety of methods have been used in order toestimate policy positions for political parties in national parliaments. This papersets out to apply a novel computational method called Wordfish and apply it to aheavily under-researched form of political text, parliamentary speeches.Quantitative studies of this sort are even more rare the case in Sweden in whichquantitative studies on parliamentary speeches is close to non-existent. In anattempt to contribute to fill the gap in literature this study uses scaling techniqueusing word frequencies and to estimate positions of 4 Swedish political partiesalong two dimensions in political space. By observing the estimated movement bythese 4 parties over a 20-year time period one can draw conclusions of theSwedish political space and how it has shifted over time. One can also evaluatethe chosen method on this specific research material, a combination that has notbeen seen before. The results suggest that there is fine tuning that needs to bedone when using Wordfish considering the output was not in line with conventionalwisdom and previous research. The studied did show interesting movementtowards the authoritarian extreme by the two largest parties in Swedish nationalpolitics.

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