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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

Modélisation hybride du canal de propagation dans un contexte industriel / A hybrid radio channel model for industrial environment

Hariri Essamlali, Kaoutar El 19 December 2014 (has links)
Ce travail de thèse concerne la modélisation du canal de propagation dans les milieux industriels. Dans ce contexte, le canal de propagation a un comportement différent de celui classiquement rencontré en indoor. Cela est dû à l'aménagement des bâtiments qui sont plus grand et ouverts ainsi qu'à la présence de machines, d'objets mobiles et d'autres matériaux métalliques rencontrés dans ces environnements. Ainsi, les modèles de canaux indoor existants ne sont plus valides. L'utilisation de modèles déterministes comme alternative est possible mais limitée en raison du temps de calcul qui en découle.Pour répondre à cette problématique, nous proposons un modèle hybride de canal s'inspirant d'une méthode à tracer de rayons 3D et du modèle WINNER. L'originalité de ce modèle repose sur son caractère hybride consistant, en prétraitement, à partitionner l'environnement en zones de visibilité ou de non-visibilité «faible» et «forte» sur des critères déterministes liés à la propagation des ondes. Un modèle statistique, type WINNER, reprenant le concept de cluster est ensuite "joué" au sein de chacune des ces zones reproduisant ainsi fidèlement l'évolution des paramètres caractéristiques des clusters identifiés. Nous avons validé notre modèle en le comparant d'abord à un modèle déterministe et ensuite à la mesure. Sa robustesse ainsi que celle de WINNER sont testées en les simulant dans trois environnements différents et en les comparant au modèle déterministe à tracer de rayons. / This thesis focuses on the modeling of the propagation channel in industrial environments. In this context, the propagation channel has a different behavior than typically encountered in indoor. This is due to the construction of buildings that are larger and open and the presence of machines, moving objects and metal materials encountered in these environments. Thus, the existing indoor channel models are not valid. Using deterministic models as an alternative is possible, but limited by the computing time.To address this problem, we propose a hybrid channel model for communications in industrial environments inspired by a ray tracing method and Winner model. The originality of this model is its hybrid nature consisting, in preprocessing, in partitionning the environment in areas of visibility or non-visibility «weak» and «strong» based on deterministic criteria related to the wave propagation. A statistical model, as WINNER , using the concept of cluster is then played in each of these areas and faithfully reproducing the evolution of the characteristic parameters of the identified clusters. We have validated our model by comparing it firstly to a deterministic model and then to measurement. Its robustness as well that of WINNER are tested by simulating them in three different environments and by comparing them with the deterministic model.
22

Resolving the Complexity of Some Fundamental Problems in Computational Social Choice

Dey, Palash January 2016 (has links) (PDF)
In many real world situations, especially involving multiagent systems and artificial intelligence, participating agents often need to agree upon a common alternative even if they have differing preferences over the available alternatives. Voting is one of the tools of choice in these situations. Common and classic applications of voting in modern applications include collaborative filtering and recommender systems, metasearch engines, coordination and planning among multiple automated agents etc. Agents in these applications usually have computational power at their disposal. This makes the study of computational aspects of voting crucial. This thesis is devoted to a study of computational complexity of several fundamental algorithmic and complexity-theoretic problems arising in the context of voting theory. The typical setting for our work is an “election”; an election consists of a set of voters or agents, a set of alternatives, and a voting rule. The vote of any agent can be thought of as a ranking (more precisely, a complete order) of the set of alternatives. A voting profile comprises a collection of votes of all the agents. Finally, a voting rule is a mapping that takes as input a voting profile and outputs an alternative, which is called the “winner” or “outcome” of the election. Our contributions in this thesis can be categorized into three parts and are described below. Part I: Preference Elicitation. In the first part of the thesis, we study the problem of eliciting the preferences of a set of voters by asking a small number of comparison queries (such as who a voter prefers between two given alternatives) for various interesting domains of preferences. We commence with considering the domain of single peaked preferences on trees in Chapter 3. This domain is a significant generalization of the classical well studied domain of single peaked preferences. The domain of single peaked preferences and its generalizations are hugely popular among political and social scientists. We show tight dependencies between query complexity of preference elicitation and various parameters of the single peaked tree, for example, number of leaves, diameter, path width, maximum degree of a node etc. We next consider preference elicitation for the domain of single crossing preference profiles in Chapter 4. This domain has also been studied extensively by political scientists, social choice theorists, and computer scientists. We establish that the query complexity of preference elicitation in this domain crucially depends on how the votes are accessed and on whether or not any single crossing ordering is a priori known. Part II: Winner Determination. In the second part of the thesis, we undertake a study of the computational complexity of several important problems related to determining winner of an election. We begin with a study of the following problem: Given an election, predict the winners of the election under some fixed voting rule by sampling as few votes as possible. We establish optimal or almost optimal bounds on the number of votes that one needs to sample for many commonly used voting rules when the margin of victory is at least n (n is the number of voters and is a parameter). We next study efficient sampling based algorithms for estimating the margin of victory of a given election for many common voting rules. The margin of victory of an election is a useful measure that captures the robustness of an election outcome. The above two works are presented in Chapter 5. In Chapter 6, we design an optimal algorithm for determining the plurality winner of an election when the votes are arriving one-by-one in a streaming fashion. This resolves an intriguing question on finding heavy hitters in a stream of items, that has remained open for more than 35 years in the data stream literature. We also provide near optimal algorithms for determining the winner of a stream of votes for other popular voting rules, for example, veto, Borda, maximin etc. Voters’ preferences are often partial orders instead of complete orders. This is known as the incomplete information setting in computational social choice theory. In an incomplete information setting, an extension of the winner determination problem which has been studied extensively is the problem of determining possible winners. We study the kernelization complexity (under the complexity-theoretic framework of parameterized complexity) of the possible winner problem in Chapter 7. We show that there do not exist kernels of size that is polynomial in the number of alternatives for this problem for commonly used voting rules under a plausible complexity theoretic assumption. However, we also show that the problem of coalitional manipulation which is an important special case of the possible winner problem admits a kernel whose size is polynomial bounded in the number of alternatives for common voting rules. \Part III: Election Control. In the final part of the thesis, we study the computational complexity of various interesting aspects of strategic behaviour in voting. First, we consider the impact of partial information in the context of strategic manipulation in Chapter 8. We show that lack of complete information makes the computational problem of manipulation intractable for many commonly used voting rules. In Chapter 9, we initiate the study of the computational problem of detecting possible instances of election manipulation. We show that detecting manipulation may be computationally easy under certain scenarios even when manipulation is intractable. The computational problem of bribery is an extensively studied problem in computational social choice theory. We study computational complexity of bribery when the briber is “frugal” in nature. We show for many common voting rules that the bribery problem remains intractable even when the briber’s behaviour is restricted to be frugal, thereby strengthening the intractability results from the literature. This forms the subject of Chapter 10.
23

Simulation d'un réseau de neurones à l'aide de transistors SET

Trinh, Franck Ky January 2010 (has links)
Ce mémoire est le résultat d'une recherche purement exploratoire concernant la définition d'une application de réseaux de neurones à base de transistors monoélectroniques (Single-Electron Transistor, SET). Il dresse un portait de l'état de l'art actuel, et met de l'avant la possibilité d'associer les SET avec la technologie actuelle (Field Electron Transistor, FET). La raison de cette association est que les SET peuvent être perçus comme un moyen de changement de paradigme, c'est-à-dire remplacer une fonction CMOS occupant une grande place par un dispositif alternatif présentant de meilleures performances ou équivalentes. Par l'intermédiaire de leurs caractéristiques électriques peu ordinaires au synonyme de"l'effet de blocage de Coulomb", les SET ont le potentiel d'être exploités intelligemment afin de tirer profit sur la consommation énergétique essentiellement. Cette problématique est présentée comme une des propositions alternatives"Beyond CMOS" aux termes de la diminution géométrique des transistors FET à la lumière de l'ITRS. Cette recherche propose d'exposer des circuits électroniques de technologie MOS complétés à l'aide de SET (circuits hybrides) et de montrer que l'on est capable de les remplacer ou les compléter (partiellement) dans des architectures à réseau de neurones. Pour cela, des simulations sous logiciel Cadence Environnement permettront de valider le comportement des circuits sur plusieurs critères tels que la vitesse de réponse et la consommation énergétique, par exemple. En résultat, seront proposées deux architectures à réseaux de neurones de fonctions différentes : une architecture Winner-Take-All et un générateur de spikes en tension. La première étant inspirée d'une publication provenant de GUIMARAES et al., veut démontrer qu'à partir d'une architecture SET existante, il est envisageable de se l'approprier et de l'appliquer aux paramètres des SET du CRN[indice supérieur 2] augmentant donc nos chances de pouvoir les concevoir dans notre groupe de recherche. Le second axe est la simulation d'un circuit capable de générer des signaux à spikes sans perte d'information, ce qui requerrait un nombre considérable de transistors FET sans l'utilisation de SET, mettant donc en valeur la réduction de composants.
24

HOW TO BE SOMEONE: A formula to Conquer the World

Garlaschi, Carla January 2012 (has links)
Volume 1. How to be someone: A formula to Conquer the world is the misunderstanding by a Latin-American of what success means in the First World. / <p>Volume 1 is the first edition of a following publication to be released every April.</p><p></p>
25

NIKΗΣ ou de la victoire sportive. Récompenses et vainqueurs en Grèce ancienne (du VIIIe s. à 146 av. J.-C.) / NIKΗΣ, of Victory. Rewards and Victors in Ancient Greece (from the 8.th BC to 146 BC)

Davadie, Axelle 21 November 2015 (has links)
Ce travail a interrogé les relations entre la victoire, la récompense et le vainqueur, dans les concours sportifs, en Grèce ancienne, du VIIIe s. av. J.-C. jusqu’à la prise de Corinthe par Mummius. Durant tous ces siècles, les concours, les récompenses et la place du vainqueur dans la cité ont connu des évolutions. Outre l’augmentation du nombre de rencontres et la constitution de la période, les récompenses ont aussi varié tant dans leur nature que dans leur signification. Nous avons étudié les rapports entre les trois termes de notre sujet selon trois perspectives : établir la victoire pour proclamer le vainqueur. Différents moyens sont alors lentement expérimentés, de la constitution d’un jury à l’équipement des lieux et à l’autopsis de la victoire, en passant par l’ouverture de nouvelles épreuves et catégories, tant humaines qu’animales. Puis comment la récompense et sa remise transforment l’athlète vainqueur sur le lieu même de son succès. A la cérémonie de proclamation et de couronnement dans le sanctuaire succèdent, dans un temps plus ou moins long, la mise en image et en mots. La victoire acquise et affirmée, la récompense reçue lui confèrent alors un statut nouveau et peuvent donner lieu à un enrichissement personnel. Dans une troisième partie nous avons analysé la relation entre l’athlète vainqueur et la cité de ses pères, selon trois axes : le premier met en évidence la rivalité entre certaines cités pour obtenir la gloire d’une proclamation. Le retour de l’athlète donne lieu à des cérémonies variées selon qu’elles sont familiales ou civiques. Enfin, nous avons confronté l’image négative transmise par certaines de nos sources à la carrière de quelques vainqueurs. / This PhD assessed the relations between victory, reward and victor in sport contests, both athletics and equestrianism, in Ancient Greece, from the 8.th century B.C. to the seizure of Corinth by Mummius. During all these centuries, increasing numbers of contests and rewards developed modifying the victor’s position in the city. By the way, cities organizing new contests, the « periodos » was established (the circuit of the Big Four Contests,) and the kind of rewards moved on the one hand to crowns and on the other to prizes. At the same time, the meaning of reward changed. We first examined the links between the three terms from three standpoints : first, reward and victor mean that victory in a contest is publicly set. Various means have been slowly tested to assert it, from building up the jury to sports facilities and victory autopsis, including new age groups or events, for humans as well as animals. Then we studied how reward and prize-giving change the athlete’s position on the spot of his victory. After he has been proclaimed and crowned in the sanctuary of the contests, the victor might publicly be praised or portrayed, even later on. Victory and reward gained give him a new position and could make him richer.
26

MODÉLISATION ET ANALYSE STATISTIQUE DES PLANS D'EXPÉRIENCE SÉQUENTIELS

Yousfi Elqasyr, Khadija 18 November 2008 (has links) (PDF)
Cette thèse est composée de deux parties. La première partie porte sur l'étude de plans d'expérience séquentiels appliqués aux essais cliniques. Nous étudions la modélisation de ces plans. Nous développons une généralisation de la règle \Play-The-Winner”. Des résultats théoriques et numériques montrent que cette généralisation conduit à des plans plus performants que les plans qui ont été récemment développés, dans le cadre des modèles d'urne de Freedman, et qui sont une généralisation de la règle \Play-The-Winner randomisée” ou d'une version modifiée de cette règle. Dans la deuxième partie, nous développons des méthodes d'inférence pour analyser les données des différents plans séquentiels considérés. Dans le cas de deux traitements, et pour la règle \play-the-winner”, nous explicitons les distributions d'échantillonnage et leurs moments factoriels. Nous en dérivons des procédures d'inférence fréquentistes (tests et intervalles de confiance conditionnels notamment) et bayésiennes non informatives. Dans le cadre bayésien, pour une classe de lois a priori convenablement choisie, sont dérivées explicitement les distributions a posteriori et les intervalles de crédibilité des paramètres d'intérêt, ainsi que les distributions prédictives. Le lien entre les tests conditionnels et les procédures bayésiennes est explicité. Les méthodes bayésiennes sont généralisées pour traiter des plans plus complexes (plusieurs traitements et/ou prise en compte de réponses différées). Des simulations montrent que les propriétés fréqentistes des procédures bayésiennes non informatives sont remarquables.
27

Sportovci jako hrdinové - konstrukce a vývoj obrazu českých olympijských medailistů / Athletes and Heroes - construction and evolution of Czech olympic medalist image

Houzar, Petr January 2009 (has links)
The diploma thesis "Athletes as heroes - construction and evolution of Czech olympic medalist image" deals with media construction of olympic Winter image and its following trasformation into national hero myth. It approaches the topic from the perspective of semiotic analysis. It informs about the key concepts of semiotics and media studies like visual communication, sign, code, myth, social construction of reality, representation and stereotype. These concepts are consequently used as tools for the analysis of photos (thein legends) and headlines in daily press. The text shows on the case of six olympic winners (between years 1998 - 2008) how Czech daily press dealt and built individual stories a basic archetypes. In its first part it offers basic theoretical frame serving to understand the hero image as the social construct. Athlete with his win attracts new - medial constructed - identity. In the second part text tries to analyse media contents that deal with athetes images immediate after their olympic victory. It arrives to following conclusions: media have a tendency to produce the stories od victory, that are gender unequal and stereotyped. And finally, text show us individual images, their basic signs and confrontation, that signifies very similar narrative pracices and zero progress in time.
28

Winner Prediction of Blood Bowl 2 Matches with Binary Classification

Gustafsson, Andreas January 2019 (has links)
Being able to predict the outcome of a game is useful in many aspects. Such as,to aid designers in the process of understanding how the game is played by theplayers, as well as how to be able to balance the elements within the game aretwo of those aspects. If one could predict the outcome of games with certaintythe design process could possibly be evolved into more of an experiment basedapproach where one can observe cause and effect to some degree. It has previouslybeen shown that it is possible to predict outcomes of games to varying degrees ofsuccess. However, there is a lack of research which compares and evaluates severaldifferent models on the same domain with common aims. To narrow this identifiedgap an experiment is conducted to compare and analyze seven different classifierswithin the same domain. The classifiers are then ranked on accuracy against eachother with help of appropriate statistical methods. The classifiers compete onthe task of predicting which team will win or lose in a match of the game BloodBowl 2. For nuance three different datasets are made for the models to be trainedon. While the results vary between the models of the various datasets the general consensus has an identifiable pattern of rejections. The results also indicatea strong accuracy for Support Vector Machine and Logistic Regression across allthe datasets.
29

OPEN INNOVATION CONTESTS IN ONLINE MARKETS: IDEA GENERATION AND IDEA EVALUATION WITH COLLECTIVE INTELLIGENCE

YANG, YANG January 2012 (has links)
To overcome constrained resources, firms can actively seek innovative opportunities from the external world. This innovation approach, called open innovation (Chesbrough 2003; Hippel 2005; Terwiesch and Ulrich 2009; Terwiesch and Xu 2008), is receiving more and more attention. Facilitated by the global Internet and emerging forms of information technology, it has become very easy for companies to generate large numbers of innovative solutions through the use of online open innovation contests or crowdsourcing contests (Archak and Sundararajan 2009; Terwiesch and Ulrich 2009; Terwiesch and Xu 2008; Yang et al. 2009).For an innovation project to succeed, it is necessary to generate not only a large number of good ideas or solutions, but also to identify those that are "exceptional" (Terwiesch and Ulrich 2009). This dissertation contains three studies that aim to improve our understanding of how best to use contests as a tool to aggregate external resources (collective intelligence) in the generation and evaluation of solutions. The first study views an innovation contest from the innovation seeker's perspective and provides insights on how to improve contest performance. The second study views an innovation contest from the innovation solver's perspective examining the characteristics and strategies of winners and solvers. Finally, in the third study, a new approach to the solution evaluation process is introduced, which is referred to as open evaluation. In this approach, a prediction market is used as an aggregation mechanism to coordinate the crowd in the evaluation of proposed solutions. These three studies make a number of contributions to the literature, addressing core issues in the area of online innovation contests. The analyses, which leverage large-scale empirical data, produce a number of profound results, which can help people to understand how best to use and design innovation contests in an online environment, for idea generation. Further, these studies present a variety of managerial implications associated with the aggregation of individual effort (collective intelligence) to evaluate the ideas that are generated by an innovation contest. We hope that our studies can help open innovation pioneers, such as Google, to systematically generate and identify exceptionally good ideas at much lower costs. By utilizing our findings, we expect that more firms will be able to adopt an open innovation strategy, both systematically and easily. / Business Administration/Management Information Systems
30

A superposição de discursos vencedores: análise pragmática das transformações jurisprudenciais em matéria tributária sob uma visão retórica realista

Aguiar, Tatiana 13 February 2014 (has links)
Made available in DSpace on 2016-04-26T20:22:32Z (GMT). No. of bitstreams: 1 Tatiana Aguiar.pdf: 641753 bytes, checksum: 632393aafafcf01345cfdf72088440fb (MD5) Previous issue date: 2014-02-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / In this study, we will examine, pragmatically, the decisions of the Superior Courts, more precisely, the positioning of these bodies´ changes in judgment, regarding tax matters, under the perspective of the Realistic Rhetoric Theory. Therefore, the first part will be devoted to the study of this theory: what it is, what its basic premises are, in which cases it distinguishes it self from the other rhetorical theories. Moreover, we will focus on issues considered important to its understanding, such as, language, truth and speech. In the second part, we will try to apply these rhetorical ideas to Tax Law, facing it as a communication system: the legal reality in its linguistic nature and legal rules in speech. We will tackle the Higher Courts as winning speech issuers, as well as analyze the phenomenon of the superposition of these speeches. To conclude, we face some legal cases in tax matters. We chose three themes that were subject to review by the Higher Courts at different times, which received two distinct placements by the same bodies which, for us, reaffirm the ideas defended in this work / No presente trabalho, analisaremos, pragmaticamente, as decisões das cortes superioras, mais precisamente, a mudança de posicionamento desses órgãos julgadores, em matéria tributária, sob a ótica da Teoria Retórica Realista. Para tanto, dedicaremos a primeira parte ao estudo desta teoria:em que consiste, quais suas premissas básicas, em que se distingue das demais teorias retóricas, além disso, cuidaremos de temas que são importantes para sua compreensão, tais como, linguagem, verdade e discurso. Na segunda parte, buscaremos aplicar essas ideias retóricas ao Direito Tributário, enxergando-o como um sistema comunicacional: a realidade jurídica em sua natureza linguística e a norma como discurso. Encararemos os Tribunais Superiores como emissores de discursos vencedores, assim como analisaremos o fenômeno da superposição dos discursos daqueles emanados. Para finalizar este trabalho, enfrentaremos alguns casos jurisprudenciais em matéria tributária. Escolhemos três temas que foram objeto de análise pelas Cortes Superioras, sendo que todas eles, em diferentes momentos, receberam dois posicionamentos distintos pelos mesmos órgãos julgadores, o que, para nós, reitera as ideias defendidas neste trabalho

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