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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.
321

APPROCHE INTELLIGENTE À BASE DE RAISONNEMENT À PARTIR DE CAS POUR LE DIAGNOSTIC EN LIGNE DES SYSTÈMES AUTOMATISÉS DE PRODUCTION / Intelligent case based reasoning approach for online diagnosis of automated production systems

Ben Rabah, Nourhène 14 December 2018 (has links)
Les systèmes automatisés de production (SAP) représentent une classe importante des systèmes industriels qui sont de plus en plus complexes vue le grand nombre d’interaction et d’interconnexion entre leurs différents composants. En conséquence, ils sont plus sensibles aux dysfonctionnements dont les conséquences peuvent être importantes en termes de productivité, de sécurité et de qualité de production. Un défi majeur est alors de développer une approche intelligente qui peut être utilisée pour le diagnostic de ces systèmes afin de garantir leurs suretés de fonctionnement. Dans le cadre de cette thèse, nous nous intéressons seulement au diagnostic des SAP ayant une dynamique discrète. Nous présentons dans le premier chapitre ces systèmes, les dysfonctionnements possibles et la terminologie du diagnostic utilisée. Ensuite, nous présentons un état de l’art de différentes méthodes et approches existantes et aussi une synthèse de ces méthodes. Cette synthèse nous a motivé de choisir une approche à base de donnée qui s’appuie sur une technique d’apprentissage automatique, qui est le raisonnement à partir de cas (RàPC). Pour cela, nous avons présenté dans le deuxième chapitre un état de l’art sur l’apprentissage automatique et ses différentes méthodes en mettant l’accent essentiellement sur le RàPC et ses utilisations pour le diagnostic des systèmes industriels. Cette étude nous a permis de proposer dans le chapitre 3 une approche d’aide au diagnostic qui se base sur le RàPC. Cette approche s’appuie sur une phase hors ligne et une phase en ligne. La phase hors ligne permet de définir un format de représentation de cas et de construire une base de cas normaux (BCN) et une base de cas défaillants (BCD) à partir d’une base de données d’historique. La phase en ligne permet d’aider les opérateurs humains de surveillance à la prise de la décision du diagnostic la plus adéquate. Les résultats des expérimentations sur un système de tri de caisses ont présentés les piliers de cette approche qui résident au niveau du format de représentation de cas proposé et au niveau de la base de cas utilisé. Pour résoudre ces problèmes et améliorer les résultats, un nouveau format de représentation de cas est proposé dans le chapitre 4. Selon ce format et à partir des données issues du système simulé après son émulation en mode normal et fautif, les cas de la base de cas initiale sont construits. Ensuite, une phase de raisonnement et d’apprentissage incrémental est présentée. Cette phase permet non seulement le diagnostic du système surveillé mais aussi d’enrichir la base de cas suite à l’apparition des nouveaux comportements inconnus. Les expérimentations présentées dans le chapitre 5 sur « le plateau tournant » qui est un sous système du système « tri de caisses » ont permis de montrer l’amélioration des résultats et aussi d’évaluer et de comparer les performances de l’approche proposée vis-à-vis certaines approches d’apprentissage automatique et vis-à-vis une approche à base de modèle pour le diagnostic du plateau tournant. / Automated production systems (APS) represents an important class of industrial systems that are increasingly complex given the large number of interactions and interconnections between their different components. As a result, they are more susceptible to malfunctions, whose consequences can be significant in terms of productivity, safety and quality of production. A major challenge is to develop an intelligent approach that can be used to diagnose these systems to ensure their operational safety. In this thesis, we are only interested in the diagnosis of APS with discrete dynamics. We present in the first chapter these systems, the possible malfunctions and the used terminology for the diagnosis. Then, we present a state of the art of the existing methods for the diagnosis of this class of systems and also a synthesis of these methods. This synthesis motivated us to choose a data-based approach that relies on a machine learning technique, which is Case-Based Reasoning (CBR). For this reason, we presented in the second chapter a state of the art on machine learning and its different methods with a focus mainly on the CBR and its uses for the diagnosis of industrial systems. This study allowed us to propose in Chapter 3 a Case Based Decision Support System for the diagnosis of APS. This system is based on an online block and an offline block. The Offline block is used to define a case representation format and to build a Normal Case Base (NCB) and a Faulty Case Base (FCB) from a historical database. The online block helps human operators of monitoring to make the most appropriate diagnosis decision. The experiments results perform on a sorting system presented the pillars of this approach, which reside in the proposed case representation format and in the used case base. To solve these problems and improve the results, a new case representation format is proposed in chapter 4. According to this format and from the data acquired from the simulated system after its emulation in normal and faulty mode, cases of the initial case base are build. Then, a reasoning and incremental learning phase is presented. This phase allows the system diagnosis and the enrichment of the case base following the appearance of new unknown behaviors. The experiments presented in Chapter 5 and perform on the 'turntable' which is a subsystem of the 'sorting system” allowed to show the improvement of the results and also to evaluate and compare the performances of the proposed approach with some automatic learning approaches and with a model-based approach to turntable diagnosis.
322

The Relationship Between Undergraduate Instructor Self- Concept and the Degree of Prosocial Behavior Exhibited by Instructors to Online Undergraduate Business First Year Students

Unknown Date (has links)
The primary goal of this quantitative study was to investigate the connection between instructor self-concept and prosocial behavior and its impact on student learning; thus, gaining more knowledge about assessment of instructor fit for online, undergraduate, business first-year experience (FYE) courses. If an instructor’s selfconcept is related to the degree of prosocial behavior exhibited, then an instructor with a higher likelihood of exhibiting prosocial behavior may be a better fit for an online, undergraduate, business FYE course. The study failed to reject all null hypotheses, showing no correlations between faculty self-concept and degree of prosocial behavior exhibited to online business firstyear students. The results did show a correlation between instructor self-concept (RSCQ score) and tendency to exhibit prosocial behavior (PTM score), which is outside of the scope of this study, but informed future research considerations discussed in Chapter 5. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2018. / FAU Electronic Theses and Dissertations Collection
323

The protection of transmission networks containing AC and DC circuits

Wang, Hualei January 2015 (has links)
In 14th August 2003, the Northeast USA suffered its worst power outage event in history. The power disturbance spreading through the system caused mal-trips of the distance relay remote back-up protections, which indeed contributed to the power outage cascading a wide area. The power outage in the Northeast USA was constrained by the presence of HVDC interconnections between the HVAC networks in Ontario and New York. The system collapse did not progress beyond the HVDC interconnection interface with Quebec. The HVDC link can regulate the voltage and current therefore impacts on the performance of the protection and system stability. The distance relay mal-operations were one of the main cause of the Northeast USA blackout as well as the other recent major large area blackouts which were pointed out by the previous papers. This thesis is focus on investigate how HVDC interconnections contribute to maintaining the power system stability. The research work investigated the performance of a distance relay to faults and disturbance on networks containing HVDC interconnection. The research work was carried out by modelling and testing a classic signal processing distance relay in a simple AC network which was based on Kunder’s two areas system using MATLAB/SIMULINK at first. Then the modeled distance relay’s performance was investigated by combining the distance relay and a simple HVDC link based on the Kunder’s two areas system. The research work firstly combined the signal processing distance relay and the HVDC link together to investigate the distance relay’s performance when the protected feeder containing DC link. The distance relay’s performance was investigated when the protected feeders containing HVDC link under fault conditions and power swing conditions. For comparison, a similar power system without HVDC link was also simulated.
324

Abundância populacional de Crypturellus noctivagus em fragmento florestal no estado do Rio Grande do sul, Brasil

Corrêa, Luiz Liberato Costa 12 May 2014 (has links)
Submitted by FERNANDA DA SILVA VON PORSTER (fdsvporster@univates.br) on 2014-09-29T17:55:07Z No. of bitstreams: 3 license_text: 22302 bytes, checksum: 1e0094e9d8adcf16b18effef4ce7ed83 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) 2014LuizLiberatoCostaCorrea.pdf: 861663 bytes, checksum: aebd96f2fd9f1fc545903347e3564ac5 (MD5) / Approved for entry into archive by Ana Paula Lisboa Monteiro (monteiro@univates.br) on 2014-10-06T14:05:32Z (GMT) No. of bitstreams: 3 license_text: 22302 bytes, checksum: 1e0094e9d8adcf16b18effef4ce7ed83 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) 2014LuizLiberatoCostaCorrea.pdf: 861663 bytes, checksum: aebd96f2fd9f1fc545903347e3564ac5 (MD5) / Made available in DSpace on 2014-10-06T14:05:32Z (GMT). No. of bitstreams: 3 license_text: 22302 bytes, checksum: 1e0094e9d8adcf16b18effef4ce7ed83 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) 2014LuizLiberatoCostaCorrea.pdf: 861663 bytes, checksum: aebd96f2fd9f1fc545903347e3564ac5 (MD5) / O presente estudo teve por objetivo avaliar a abundância e densidade populacional de Crypturellus noctivagus em um fragmento florestal entre os municípios de São Sepé e Formigueiro, Rio Grande do Sul. Dois métodos foram utilizados para a coleta de dados: transectos com bandas e amostragem por pontos. Para as amostragens foram estabelecidas cinco trilhas variando entre 500 a 900 metros, totalizando 3.400 metros de extensão. No transcorrer das trilhas foram locados 15 pontos de escuta. As amostragens foram quinzenais entre setembro de 2012 e março de 2013, utilizando os dois turnos diurnos para as amostragens, totalizando 24 amostragens por cada método. Os dados obtidos através da amostragem por transecto com bandas em 81.600m percorridos foram modelados pelo tamanho total do fragmento (450 ha) com o uso do programa Distance 5.0, indicando densidade de 3.38 espécimes por km². O esforço por pontos de escuta totalizou 120hs apresentando abundância em 1.26. Conforme os resultados obtidos, Crypturellus noctivagus se encontra isolado de outras possíveis populações que possam a vir ocorrer no Rio Grande do Sul. Devido a sua única e reduzida população conhecida caracteriza-se como uma espécie Criticamente em perigo de extinção no estado.
325

Ownership mode, cultural distance, and the extent of parent firms strategic control over subsidiaries in the PRC

Puck, Jonas, Hödl, Markus K., Filatotchev, Igor, Wolff, Hans-Georg, Bader, Benjamin 25 May 2016 (has links) (PDF)
Previous studies often associated a specific type of ownership mode with the extent of control a parent firm may have over (strategic) decision-making in a foreign subsidiary, suggesting that parent firms should have higher control over wholly-owned subsidiaries (WoS) than international joint ventures (IJVs). Building on principal agent theory, we argue that in the Chinese context higher ownership levels do not necessarily have a positive effect on the extent of control over the foreign subsidiary. We further argue that cultural distance between the parent firm and the subsidiary moderates this relationship. We test our hypotheses using data from a sample of 156 foreign subsidiaries in the People's Republic of China (PRC) and find strong support for our arguments. Our findings show that in WoS parent firms reduce their extent of control, while in IJVs parent firms increase their extent of control. Moreover, we find that extent of control over WoS (IJVs) declines (increases) when cultural distance increases. Our results have significant theoretical implications for international business (IB) research as they challenge existing views with regard to the relationship between ownership mode and control as well as the moderating effect of cultural distance.
326

Quantitative perturbation theory for compact operators on a Hilbert space

Guven, Ayse January 2016 (has links)
This thesis makes novel contributions to a problem of practical and theoretical importance, namely how to determine explicitly computable upper bounds for the Hausdorff distance of the spectra of two compact operators on a Hilbert space in terms of the distance of the two operators in operator norm. It turns out that the answer depends crucially on the speed of decay of the sequence of singular values of the two operators. To this end, 'compactness classes', that is, collections of operators the singular values of which decay at a certain speed, are introduced and their functional analytic properties studied in some detail. The main result of the thesis is an explicit formula for the Hausdorff distance of the spectra of two operators belonging to the same compactness class. Along the way, upper bounds for the resolvents of operators belonging to a particular compactness class are established, as well as novel bounds for determinants of trace class operators.
327

Možnosti e-learningu v podmínkách distančního studia na FIS VŠE Praha / Possibilities of use of e-learning applications in distance learning at FIS VŠE Prague

Turčín, Pavel January 2010 (has links)
Main subjects of this thesis are distant learning and e-learning. It provides an overview of current state of distance learning in tertiary education in Czech republic, focusing mainly on informatics programs. It identifies limitations of standard e-learning systems regarding the requirements of courses on the Faculty of Informatics and Statistics at University of Economics, Prague. Practical part of this thesis is describing implementation and use of special application that provides functionality that is not provided by standard e-learning systems.
328

Smlouvy uzavírané prostředky komunikace na dálku - úprava tzv. distančních smluv / Contracts made by means of distant communication - the regulation of so-called distant contracts

Jozová, Hana January 2012 (has links)
The agreements concluded by means of distant communication ("distance contracts") are one of the two types of Consumer Agreements explicitly defined by the Civil Code (the other type being agreements concluded outside usual business premises, "door-to-door contracts"). Consumer Agreements are not a stand-alone contractual type, but merely a specific term for those traditional contractual types (e.g. purchase agreement, agreement for work) concluded between a consumer and a supplier. For the purposes of Consumer Agreements, the supplier is defined as a person acting in the framework of his trade or other business activity, while the consumer is on the contrary a person who doesn't act in the framework of his trade or other business activity. It was the need to establish the higher standard of protection towards consumers (as a weaker contractual party) that led to the introduction of the new instrument of Consumer Agreements into the legal framework. The introduction took place through the Act No. 367/2000 Coll., which implemented into the Czech law three EC directives, namely the Council Directive 93/13/EEC on unfair terms in consumer contracts, the Council Directive 85/577/EEC to protect the consumer in respect of contracts negotiated away from business premises, and finally the Directive of the...
329

Un tutorat transversal à distance et en ligne pour l’université / A transversal tutoring online in distance education for the university

Micholet, Marie 29 November 2018 (has links)
Ce travail de thèse a pour projet d’interroger les pratiques de tuteurs en ligne par l'analyse d'interactions tutorales situées étudiants/tuteur produites par le biais d’outils numériques de communication lors de formations institutionnelles à distance et en ligne. L’objectif est de dégager les indices susceptibles d'apporter des éléments de référence pour définir l’intervention tutorale transversale. Il s'agit de comprendre les processus de construction concernant les spécificités des missions du tuteur et les attentes de leur engagement dans l'enseignement et l'apprentissage vers la proposition d’une définition d’un tutorat transversal et de sa mise en place dans les formations à distance pour l’université. Le champ théorique est celui de l'ethnographie dans ses présupposés théoriques (démarche empirique) et par ses pratiques méthodologiques. Nous développons une enquête afin d'observer les interactions au travers des interventions tutorales qui s’attachent à accompagner les étudiants non sur un enseignement précis mais dans un positionnement transversal où se produisent les échanges entre des étudiants de master et une personne tutrice pendant deux années universitaires. La multimodalité des interactions tutorales permettra la constitution de collections de données émises par l'intermédiaire de communication numérique (outils synchrones et asynchrones). Ces données se composent de traces écrites laissées par les étudiants sur les forums de discussion, dans la correspondance par courrier électronique et dans des conversations synchrones. Les actions conversationnelles développées dans ce contexte permettront alors d’interpréter les phénomènes mis à jour lors de l’enquête. Cette recherche offre ainsi l’opportunité de proposer une comparaison entre la fonction académique de tuteur en ligne et la réalité de sa position dans les formations à distance et de soumettre des pistes pour une meilleure intégration du tutorat en ligne dans les formations. L’objectif final étant de proposer un prototype des pratiques tutorales dans la perspective d’une mise en place d'un tutorat en ligne dans les formations numériques universitaires. / The goal of this thesis is to assess the online tutoring through an analysis of tutoring interactions between students and tutors using digital communication tools during distance and online institutional education. The objective is to identify indexes that can be referential in determining cross-cutting tutorial activity. It is an attempt to understand the process of determining the specificities of the missions of tutors and the expectations of their participation in teaching and learning with the view to establish an cross-cutting tutoring activity and its implementation in distance education for the university. The theoretical framework is that of ethnography in its theory (empirical approach) and its methodological approaches. We are preparing a survey in order to observe tutoring-based interactions which focus on guiding students not in a specific discipline, but rather in a cross-section of disciplines, characterised by discussions between Master’s Degree students and a tutor for two years. The multi-modality of tutoring will lead to the collection of data resulting from digital communication tools (both synchronous and non-synchronous). The data will thus be composed of both written traces left by students in discussion forums, email and in synchronous conversations. Conversations carried out within this context will thus enable the analysis of the phenomena obtained during the survey. This study thus serves as an opportunity to compare the academic duty of online tutors and the reality of their place in distance education and to provide the way forward for a better integration of online tutoring into education. The overall goal is to come up with a prototype of tutoring activities with the view to create an online tutoring in digital education.
330

Subdifferentials of distance functions in Banach spaces.

January 2010 (has links)
Ng, Kwong Wing. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (p. 123-126). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgments --- p.iii / Contents --- p.v / Introduction --- p.vii / Chapter 1 --- Preliminaries --- p.1 / Chapter 1.1 --- Basic Notations and Conventions --- p.1 / Chapter 1.2 --- Fundamental Results in Banach Space Theory and Variational Analysis --- p.4 / Chapter 1.3 --- Set-Valued Mappings --- p.6 / Chapter 1.4 --- Enlargements and Projections --- p.8 / Chapter 1.5 --- Subdifferentials --- p.11 / Chapter 1.6 --- Sets of Normals --- p.18 / Chapter 1.7 --- Coderivatives --- p.24 / Chapter 2 --- The Generalized Distance Function - Basic Estimates --- p.27 / Chapter 2.1 --- Elementary Properties of the Generalized Distance Function --- p.27 / Chapter 2.2 --- Frechet-Like Subdifferentials of the Generalized Distance Function --- p.32 / Chapter 2.3 --- Limiting and Singular Subdifferentials of the Generalized Distance - Function --- p.44 / Chapter 3 --- The Generalized Distance Function - Estimates via Intermediate Points --- p.73 / Chapter 3.1 --- Frechet-Like and Limiting Subdifferentials of the Generalized Dis- tance Function via Intermediate Points --- p.74 / Chapter 3.2 --- Frechet and Proximal Subdifferentials of the Generalized Distance Function via Intermediate Points --- p.90 / Chapter 4 --- The Marginal Function --- p.95 / Chapter 4.1 --- Singular Subdifferentials of the Marginal Function --- p.95 / Chapter 4.2 --- Singular Subdifferentials of the Generalized Marginal Function . . --- p.102 / Chapter 5 --- The Perturbed Distance Function --- p.107 / Chapter 5.1 --- Elementary Properties of the Perturbed Distance Function --- p.107 / Chapter 5.2 --- The Convex Case - Subdifferentials of the Perturbed Distance Function --- p.111 / Chapter 5.3 --- The Nonconvex Case - Frechet-Like and Proximal Subdifferentials of the Perturbed Distance Function --- p.113 / Bibliography --- p.123

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