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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

Teamwork Exercises and Technological Problem Solving with First-Year Engineering Students: An Experimental Study

Springston, Mark R. 08 September 2005 (has links)
An experiment was conducted investigating the utility of teamwork exercises and problem structure for promoting technological problem solving in a student team context. The teamwork exercises were designed for participants to experience a high level of psychomotor coordination and cooperation with their teammates. The problem structure treatment was designed based on small group research findings on brainstorming, information processing, and problem formulation. First-year college engineering students (N = 294) were randomly assigned to three levels of team size (2, 3, or 4 members) and two treatment conditions: teamwork exercises and problem structure (N = 99 teams). In addition, the study included three non-manipulated, independent variables: team gender, team temperament, and team teamwork orientation. Teams were measured on technological problem solving through two conceptually related technological tasks or engineering design activities: a computer bridge task and a truss model task. The computer bridge score and the number of computer bridge design iterations, both within subjects factors (time), were recorded in pairs over four 30-minute intervals. For the last two intervals with the computer bridge, teams started construction of the truss model task, which created low and high task load conditions for the computer bridge: another within subjects factor. A repeated measures ANOVA was used to analyze time (computer bridge) by factor interactions. No significant time by teamwork exercises or time by problem structure interactions on computer bridge scores were found [F(2.31, 198.46) = 0.10, p = .928; F(2.31, 198.46) = 0.03, p = .984]. There was a significant interaction between the factors of time and team size [F(4.62, 198.46) = 2.75, p = .023]. An ANOVA was conducted with the between subject factors on the truss model task. A significant main effect was found for teamwork exercises [F(1, 86) = 2.84, p = .048, one-tailed], but not for problem structure or team size. Post hoc analyses were conducted for team size on computer bridge and iteration scores over time, as well as teamwork exercises effects for each team size. Findings and their implications were reported, along with suggestions for future research on technological problem solving in a team context. / Ph. D.
22

Ocenenie spolocnosti Zabka Polska, SA / Business valuation of Zabka Polska, SA

Dratva, Martin January 2011 (has links)
The aim of this thesis is business valuation of Zabka Polska, SA. This company operates retail convenience stores in Poland. The goal of this thesis is to estimate fair market value of the Company as of December 31st 2010. DCF Equity valuation method has been used as the main valuation method. Comparable traded companies and comparable historic transaction analyses methods have been used as complementary valuation methods. Master thesis has similar structure as legal valuation report and is divided into six parts.
23

High accuracy computational methods for the semiclassical Schrödinger equation

Singh, Pranav January 2018 (has links)
The computation of Schrödinger equations in the semiclassical regime presents several enduring challenges due to the presence of the small semiclassical parameter. Standard approaches for solving these equations commence with spatial discretisation followed by exponentiation of the discretised Hamiltonian via exponential splittings. In this thesis we follow an alternative strategy${-}$we develop a new technique, called the symmetric Zassenhaus splitting procedure, which involves directly splitting the exponential of the undiscretised Hamiltonian. This technique allows us to design methods that are highly efficient in the semiclassical regime. Our analysis takes place in the Lie algebra generated by multiplicative operators and polynomials of the differential operator. This Lie algebra is completely characterised by Jordan polynomials in the differential operator, which constitute naturally symmetrised differential operators. Combined with the $\mathbb{Z}_2$-graded structure of this Lie algebra, the symmetry results in skew-Hermiticity of the exponents for Zassenhaus-style splittings, resulting in unitary evolution and numerical stability. The properties of commutator simplification and height reduction in these Lie algebras result in a highly effective form of $\textit{asymptotic splitting:} $exponential splittings where consecutive terms are scaled by increasing powers of the small semiclassical parameter. This leads to high accuracy methods whose costs grow quadratically with higher orders of accuracy. Time-dependent potentials are tackled by developing commutator-free Magnus expansions in our Lie algebra, which are subsequently split using the Zassenhaus algorithm. We present two approaches for developing arbitrarily high-order Magnus--Zassenhaus schemes${-}$one where the integrals are discretised using Gauss--Legendre quadrature at the outset and another where integrals are preserved throughout. These schemes feature high accuracy, allow large time steps, and the quadratic growth of their costs is found to be superior to traditional approaches such as Magnus--Lanczos methods and Yoshida splittings based on traditional Magnus expansions that feature nested commutators of matrices. An analysis of these operatorial splittings and expansions is carried out by characterising the highly oscillatory behaviour of the solution.
24

Itérations chaotiques pour la sécurité de l'information dissimulée / Chaotic iterations for the Hidden Information Security

Friot, Nicolas 05 June 2014 (has links)
Les systèmes dynamiques discrets, œuvrant en itérations chaotiques ou asynchrones, se sont avérés être des outils particulièrement intéressants à utiliser en sécurité informatique, grâce à leur comportement hautement imprévisible, obtenu sous certaines conditions. Ces itérations chaotiques satisfont les propriétés de chaos topologiques et peuvent être programmées de manière efficace. Dans l’état de l’art, elles ont montré tout leur intérêt au travers de schémas de tatouage numérique. Toutefois, malgré leurs multiples avantages, ces algorithmes existants ont révélé certaines limitations. Cette thèse a pour objectif de lever ces contraintes, en proposant de nouveaux processus susceptibles de s’appliquer à la fois au domaine du tatouage numérique et au domaine de la stéganographie. Nous avons donc étudié ces nouveaux schémas sur le double plan de la sécurité dans le cadre probabiliste. L’analyse de leur biveau de sécurité respectif a permis de dresser un comparatif avec les autres processus existants comme, par exemple, l’étalement de spectre. Des tests applicatifs ont été conduits pour stéganaliser des processus proposés et pour évaluer leur robustesse. Grâce aux résultats obtenus, nous avons pu juger de la meilleure adéquation de chaque algorithme avec des domaines d’applications ciblés comme, par exemple, l’anonymisation sur Internet, la contribution au développement d’un web sémantique, ou encore une utilisation pour la protection des documents et des donnés numériques. Parallèlement à ces travaux scientifiques fondamentaux, nous avons proposé plusieurs projets de valorisation avec pour objectif la création d’une entreprise de technologies innovantes. / Discrete dynamical systems by chaotic or asynchronous iterations have proved to be highly interesting toolsin the field of computer security, thanks to their unpredictible behavior obtained under some conditions. Moreprecisely, these chaotic iterations possess the property of topological chaos and can be programmed in anefficient way. In the state of the art, they have turned out to be really interesting to use notably through digitalwatermarking schemes. However, despite their multiple advantages, these existing algorithms have revealedsome limitations. So, these PhD thesis aims at removing these constraints, proposing new processes whichcan be applied both in the field of digital watermarking and of steganography. We have studied these newschemes on two aspects: the topological security and the security based on a probabilistic approach. Theanalysis of their respective security level has allowed to achieve a comparison with the other existing processessuch as, for example, the spread spectrum. Application tests have also been conducted to steganalyse and toevaluate the robustness of the algorithms studied in this PhD thesis. Thanks to the obtained results, it has beenpossible to determine the best adequation of each processes with targeted application fields as, for example,the anonymity on the Internet, the contribution to the development of the semantic web, or their use for theprotection of digital documents. In parallel to these scientific research works, several valorization perspectiveshave been proposed, aiming at creating a company of innovative technology.
25

GPU-enhanced power flow analysis / Calcul de Flux de Puissance amélioré grâce aux Processeurs Graphiques

Marin, Manuel 11 December 2015 (has links)
Cette thèse propose un large éventail d'approches afin d'améliorer différents aspects de l'analyse des flux de puissance avec comme fils conducteur l'utilisation du processeurs graphiques (GPU). Si les GPU ont rapidement prouvés leurs efficacités sur des applications régulières pour lesquelles le parallélisme de données était facilement exploitable, il en est tout autrement pour les applications dites irrégulières. Ceci est précisément le cas de la plupart des algorithmes d'analyse de flux de puissance. Pour ce travail, nous nous inscrivons dans cette problématique d'optimisation de l'analyse de flux de puissance à l'aide de coprocesseur de type GPU. L'intérêt est double. Il étend le domaine d'application des GPU à une nouvelle classe de problème et/ou d'algorithme en proposant des solutions originales. Il permet aussi à l'analyse des flux de puissance de rester pertinent dans un contexte de changements continus dans les systèmes énergétiques, et ainsi d'en faciliter leur évolution. Nos principales contributions liées à la programmation sur GPU sont: (i) l'analyse des différentes méthodes de parcours d'arbre pour apporter une réponse au problème de la régularité par rapport à l'équilibrage de charge ; (ii) l'analyse de l'impact du format de représentation sur la performance des implémentations d'arithmétique floue. Nos contributions à l'analyse des flux de puissance sont les suivantes: (ii) une nouvelle méthode pour l'évaluation de l'incertitude dans l'analyse des flux de puissance ; (ii) une nouvelle méthode de point fixe pour l'analyse des flux de puissance, problème que l'on qualifie d'intrinsèquement parallèle. / This thesis addresses the utilization of Graphics Processing Units (GPUs) for improving the Power Flow (PF) analysis of modern power systems. Currently, GPUs are challenged by applications exhibiting an irregular computational pattern, as is the case of most known methods for PF analysis. At the same time, the PF analysis needs to be improved in order to cope with new requirements of efficiency and accuracy coming from the Smart Grid concept. The relevance of GPU-enhanced PF analysis is twofold. On one hand, it expands the application domain of GPU to a new class of problems. On the other hand, it consistently increases the computational capacity available for power system operation and design. The present work attempts to achieve that in two complementary ways: (i) by developing novel GPU programming strategies for available PF algorithms, and (ii) by proposing novel PF analysis methods that can exploit the numerous features present in GPU architectures. Specific contributions on GPU computing include: (i) a comparison of two programming paradigms, namely regularity and load-balancing, for implementing the so-called treefix operations; (ii) a study of the impact of the representation format over performance and accuracy, for fuzzy interval algebraic operations; and (iii) the utilization of architecture-specific design, as a novel strategy to improve performance scalability of applications. Contributions on PF analysis include: (i) the design and evaluation of a novel method for the uncertainty assessment, based on the fuzzy interval approach; and (ii) the development of an intrinsically parallel method for PF analysis, which is not affected by the Amdahl's law.
26

Iterative tensor factorization based on Krylov subspace-type methods with applications to image processing

UGWU, UGOCHUKWU OBINNA 06 October 2021 (has links)
No description available.
27

Analýza a modelování přenosu signálu ve standardech DVB-H/SH / Analysis and Simulation of the Signals Transmission in the DVB-H/SH Standards

Polák, Ladislav January 2013 (has links)
Tato disertační práce se zabývá analýzou, simulací a měřením zpracování a přenosu signálů digitální televize pro příjem mobilního TV vysílání ve standardech DVB-H a DVB-SH. Tyto standardy vycházejí z předpokladu, že příjem signálu je charakterizován modely přenosových kanálů s vícecestným šířením. Tyto, tzv. únikové kanály, jsou charakterizovány hlavně zpožděním a ziskem jednotlivých cest. V závislosti na dalších parametrech (rychlost přijímače, Dopplerovské spektrum), je možné rozdělit únikové kanály do třech hlavních skupin: mobilní, přenosné a fixní. Dá se předpokládat, že v různých modelech kanálů bude přenášený signál různě ovlivněn. Proto je potřebné najít optimální parametry systémů (DVB-H/SH) pro kvalitní příjem vysílaných služeb mobilní televize, což je hlavním cílem této disertační práci. Pro tento účel byly vytvořeny dvě vhodné aplikace (jedna pro DVB-H a jedna pro DVB-SH) s GUI v prostředí MATLAB, které umožňují simulovat a analyzovat míru zkreslení signálu v případě mobilních, přenosných a fixních scénářů přenosu. Navíc, tyto aplikace obsahují i druhý samostatný simulátor pro nastavení a modifikaci parametrů jednotlivých přenosových cest. Díky tomu je možné zhodnotit vliv parametrů celého systému a kanálových modelů na dosaženou chybovost (BER a MER) a kvalitu přenosu. Ve všech přenosových scénářích (v závislosti na poměru C/N) byly získané, vyhodnocené a diskutované zkreslení signálů. Navíc, u standardu DVB-H, všechny získané výsledky ze simulací byly ověřeny měřením. Rozdíly mezi dosaženými výsledky (simulace a měření) byly rovněž podrobeny diskuzi. Tuto disertační práci je možné rozdělit do čtyř hlavních částí. První část disertační práce se zabývá rešerší současného vývoje v oblasti digitálního televizního vysílání na mobilní terminály ve standardech DVB-H/SH. Na konci této části jsou jasně popsány cíle této disertační práce. Druhá část práce je zaměřená na stručný popis blokového diagramu vysílačů v obou standardech DVB-H/SH. Dále jsou stručně popsány modely přenosových kanálů, které se používají pro modelování přenosu signálu. Stručný popis vytvořených aplikací, i s vývojovým diagramem, které jsou vhodné pro simulaci a analýzu přenosu v DVB-H/SH, jsou popsány v třetí části práce. Čtvrtá a nejdelší část této disertační práce se zabývá vyhodnocením získaných výsledků ze simulací a měření.

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