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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.
61

Noncooperative Games for Autonomous Consumer Load Balancing Over Smart Grid

Agarwal, Tarun 2010 August 1900 (has links)
Traditionally, most consumers of electricity pay for their consumption according to a fixed-rate. The few existing implementations of real time pricing have been restricted to large industrial consumers, where the benefits could justify the high implementation cost. With the advancement of Smart Grid technologies, large scale implementation of variable-rate metering will be more practical. Consumers will be able to control their electricity consumption in an automated fashion, where one possible scheme is to have each individual maximize their own utility as a noncooperative game. In this thesis, noncooperative games are formulated among the consumers of Smart Grid with two real-time pricing schemes, where the Nash equilibrium operation points are investigated for their uniqueness and load balancing properties. The first pricing scheme charges a price according to the average cost of electricity borne by the retailer and the second charges according to a time-variant increasing-block price. The zero revenue model and the constant revenue rate model, are the two revenue models being considered. The relationship between these games and certain congestion games, known as atomic flow games from the computer networking community, is demonstrated. It is shown that the proposed noncooperative game formulation falls under the class of atomic splittable flow games. It is shown that the Nash equilibrium exists for four different cases, with different pricing schemes and revenue models, and is shown to be unique for three of the cases, under certain conditions. It is shown that both pricing schemes lead to similar electricity loading patterns when consumers are interested only in the minimization of electricity costs. Finally, the conditions under which the increasing-block pricing scheme is preferred over the average cost based pricing scheme are discussed.
62

Resource management in wireless networks

Pillutla, Laxminarayana S. 05 1900 (has links)
This thesis considers resource management issues in wireless sensor networks (WSNs), wireless local area networks (WLANs), and cognitive radio (CR) networks. Since energy is a critical resource in WSNs, we consider energy minimization techniques based on explicit node cooperation and distributed source coding (DSC). The explicit node cooperation based on space time block codes (STBC) improves energy efficiency of WSNs, by reducing the energy consumption per bit of each sensor node. The DSC on the other hand exploits the spatial correlation in WSNs, and thus reduces the data generated in a WSN. For the purpose of our analysis, we model the spatial correlation according to a linear Gauss-Markov model. Through our numerical results, we observe that the node cooperation combined with DSC can improve energy efficiency for many cases of interest. A unique aspect of our work is we obtain important structural results using the concepts from monotone comparative statics. These structural results provide insights into the general design of WSNs. Through our numerical results, we also demonstrate that, the cooperation based transmission can achieve better mutual information (MI)-energy tradeoff than the non-cooperation based transmission scheme. From the perspective of WLANs, we propose a price based approach to regulate the channel occupancy of low rate users, which is known to be the primary cause for low overall throughput in WLANs. Owing to the decentralized nature of WLANs we use non-cooperative game theory as a tool for analysis. Specifically, we use supermodular game theory. Through our analysis, we show that an increase in price leads to an increase in rate of WLAN users. We also prove that the best response dynamics indeed converge to the Nash equilibrium of the underlying non-cooperative game. Through our numerical results, we demonstrate that by proper tuning of the price, the proposed price based approach can lead to an improvement in overall throughput of a WLAN. Finally from the perspective of CR networks, we consider the impact of number of channels captured by a secondary user on its transmission control protocol (TCP) throughput. From our simulation results it was found that, there exists a definite optimal number of channels a secondary user needs to capture, to maximize its TCP throughput.
63

Spatial Heterogeneity and Equilibrium

Yegorov, Yuri 23 February 1999 (has links)
This thesis consists of five chapters, based on four different articles. All of them are devoted to different aspects of spatial heterogeneity and its impact on economic equilibrium in space. The concept of heterogeneous continuous space is discussed in the introductory chapter.The first model "Equilibrium in Continuous Space under Decentralized Production" addresses the issue of the impact of differences across locations in exogeneous productivity on the structure of equilibrium prices, production and trade. The goal is to describe the general equilibrium in a spatially decentralized economy, when production, consumption and markets are distributed in continuous space and transportation costs are essentially linear. It is shown that an autarky equilibrium can exist only if transport costs are high enough. In the general case, the general equilibrium in this model includes some endogeneously determined trade areas, with flows of goods across space, and autarky areas where production and consumption activities take place only at the same point. An analytical solution in explicit functions is obtained; it contains equilibrium prices, labor supply and flows of goods as functions of the spatial variable. The model can be applied to a set of practical questions in regional economics. In particular, it is able to describe persistent price differentials across regions and non-local consequences of road construction and transportation cost shocks for the economy. The differences across locations in population density may have either historical or economic reasons.The second model "Hotelling's Revival" extends a well-known research of H.Hotelling (1929) to the two-dimensional case with spatially heterogeneous demand density, preserving the rest of his classical assumptions. It is shown that the problem of demand discontinuity in the one-dimensional model, which was discovered by d'Aspremont, Gabszewich and Thisse (1979), disappears in this case. This also holds for any bounded distribution of consumers on any compact set on a plane, which can describe real geographical situations. Demand continuity still holds for any transport costs, strictly increasing in distance and not necessarily linear. Although this is sufficient for the existence of Nash equilibrium in mixed strategies, in pure strategies it exists only for some subset of cases. Examples of both existence and non-existence are constructed, and for some family of densities the separation point between the two cases is found.The third model addresses locational choice of heterogeneous consumers, when land is also heterogeneous in quality. It is based on two articles. The first, "Dacha Pricing", is presented in chapter 4 and studies the problem of locational rent in a city-neighbourhood when utility includes both the impact of transport costs and time for transportation. For the case of identical agents the problem is solved explicitly and comparative statics with respect to exogeneous changes in transport cost and speed is studied. For the case of agents who are heterogeneous with respect to their income, a solution is also obtained. The model explains some evidence about dacha pricing in Russia and its dynamics during the transition period. The second article related to this model is "Location and Land Size Choice by Heterogeneous Agents". It generalizes the first one and form a separate chapter 5. A new approach about the general equilibrium allocation of heterogeneous divisible good (like land) among a continuum of heterogeneous consumers is proposed. The model is based on continuity of primitives which allow not only to finding a general equilibrium solution in a class of continuous functions, but also to treat the solution to a continuous problem as the limit of the corresponding sequence of discrete problems. This solves one of Berliant's paradoxes, related to spatial economics. The multiplicity of equilibria is shown to take place.
64

Teoremas de ponto fixo, teoria dos jogos e existência do Equilíbrio de Nash em jogos finitos em forma normal

Guarnieri, Felipe Milan January 2018 (has links)
Neste trabalho demonstram-se os teoremas de ponto fixo de Brouwer e Kakutani com o objetivo de provar a existência do equilíbrio de Nash em jogos finitos em forma normal. No primeiro capítulo apresentam-se as definições de teoria dos jogos, começando com jogos finitos em forma normal e terminando com o conceito de equilíbrio de Nash. Na primeira seção do capítulo dois desenvolve-se a teoria de simplexes, em Rn, e se demonstra o teorema de Brouwer. Na seção seguinte, são relacionadas as propriedades de semi-continuidade superior e gráfico fechado em set functions, para então provar os teoremas de Celina e von Neumann que, em conjunto com o teorema de Brouwer, resultam no teorema de Kakutani no fim da seção. Como último resultado é demonstrado o teorema de existência do equilíbrio de Nash em jogos finitos em forma normal através do teorema de Kakutani, mostrando que o equilíbrio de Nash é um ponto fixo de uma set function. / In this work, the fixed-point theorems of Kakutani and Brouwer are proved with the intention of showing the existence of Nash equilibrium in finite normal-form games. In the first chapter the needed definitions of game theory are shown, starting with finite normal-form games and ending with the concept of Nash equilibrium. In the first section of chapter two, simplex theory in Rn is developed and then the Brouwer fixer point theorem is proved. In the next section, some relations of upper hemi-continuity and closed graph in set functions are shown, then proving the theorems of Celina and von Neumann that, along with Brouwer theorem, result in Kakutani fixed-point theorem in the end of the section. As the last result, the existence of Nash equilibrium in finite normal-form games is proved through Kakutani’s theorem, relating the Nash equilibrium to the fixed-point of a set function.
65

Bilevel optimization of Eco-Industrial parks for the design of sustainable resource networks / Optimisation bi-niveau d'écoparcs industriels pour une gestion durable des ressources

Ramos, Manuel 27 September 2016 (has links)
Ce travail présente une optimisation bi-niveau pour la conception de réseaux durables de ressources dans les parcs éco-industriels (EIP). Tout d'abord, les méthodes d'optimisation multiobjectif sont explorées afin de gérer la nature multicritère des problèmes de conception de réseaux dans les EIP. Ensuite, différents cas d’étude sont explorés et analysés afin de maintenir un équilibre concernant les coûts opératoires des usines, tout en minimisant la consommation des ressources naturelles. Ainsi, le problème est modélisé selon une structure bi-niveau reprenant les concepts de la théorie des jeux, où les usines des entreprises jouent un jeu de Nash entre elles, tout en étant dans une structure de jeu de Stackelberg avec l'autorité environnementale. Cette structure définit un modèle qui doit être transformé en un problème MOPEC (Multiple Optimization Problems with Equilibrium Constraints). Différents cas d’étude sont explorés : le premier cas est le réseau d'eau mono-polluant d’un EIP dans lequel l’influence des paramètres opératoires des usines est étudiée afin de déterminer ceux qui favorisent la symbiose entre les usines. Le réseau d'eau est composé d'un nombre fixe de procédés et d’unités de régénération où les concentrations maximales d’entrée et de sortie des polluants sont définies a priori. L'objectif est alors de déterminer quelles sont les allocations entre procédés et unités de régénération. Les résultats obtenus mettent en évidence les avantages de la structure du modèle proposée par rapport aux approches multiobjectif traditionnelles, en obtenant des gains économiques équilibrés d’usines différentes (gains entre 12-25%) tout en maintenant une faible consommation globale des ressources. Ensuite, d'autres études de cas sont abordées à l'aide de la structure bi-niveau : il s’agit d'inclure simultanément les réseaux d'énergie et d’eau dans une formulation multileader multi-follower où les deux «autorités » environnementales sont supposées jouer un jeu non-coopératif de Nash. Dans un premier cas, le gain économique est plus important en incluant des réseaux d'énergie dans la structure de l’EIP. La deuxième étude de cas industriel explore un modèle de réseau d’utilités offre-demande où l'autorité environnementale vise à minimiser les émissions totales de CO2 dans le parc. La conclusion des différents cas explorés montre des résultats extrêmement favorables en termes de coût et d’impact environnemental ce qui vise à encourager les entreprises à participer à l'EIP. / This work presents a bilevel programming framework for the design of sustainable resource networks in eco-industrial parks (EIP). First, multiobjective optimization methods are explored in order to manage the multi-criteria nature of EIP network design problems. Then, different case studies are modeled in order to minimize and maintain in equilibrium participating plants operating costs while minimizing resource consumption. Thus, the structure of the model is constituted by a bilevel programming framework where the enterprises’ plants play a Nash game between them while being in a Stackelberg game structure with the authority. This structure defines a model which, in order to be solved, has to be transformed into a MOPEC (Multiple Optimization Problems with Equilibrium Constraints) structure. Regarding the case studies, monocontaminant water networks in EIP are studied first, where the influence of plants operating parameters are studied in order to determine the most important ones to favor the symbiosis between plants. The water network is composed of a fixed number of process and water regeneration units where the maximal inlet and outlet contaminant concentrations are defined a priori. The aim is to determine which processes are interconnected and the water regeneration allocation. Obtained results highlight the benefits of the proposed model structure in comparison with traditional multiobjective approaches, by obtaining equilibrate different plants operating costs (i.e. gains between 12-25%) while maintaining an overall low resource consumption. Then, other case studies are approached by using the bilevel structure to include simultaneously energy networks in a multi-leader-multi-follower formulation where both environmental authorities are assumed to play a noncooperative Nash game. In the first case study, economic gain is proven to be more significant by including energy networks in the EIP structure. The second industrial case study explores a supply-demand utility network model where the environmental authority aims to minimize the total equivalent CO2 emissions in the EIP. In all cases, the enterprises’ plants are encouraged to participate in the EIP by the extremely favorable obtained results.
66

Sobre teoremas de equilíbrio de Nash / On Nash equilibrium theorems

Thais Fernanda Mendes Monis 27 August 2010 (has links)
Nesse trabalho, aplicando métodos da Topologia Algébrica, nós obtivemos novas versões do teorema de equilíbrio de Nash. Nós definimos um conceito de equilíbrio local para jogos não cooperativos, o chamado equilíbrio local fraco, e demonstramos sua existência quando os espaços de estratégia são variedades diferenciáveis e as funções payoff são continuamente diferenciáveis. Nós demonstramos a ineficiência do equilíbrio local fraco no sentido de Pareto / In this work, applying methods of Algebraic Topology, we obtain new versions of the Nash equilibrium theorem. We define a concept of local equilibrium for non-cooperative games, the socalled weak local equilibrium, and we prove its existence when the spaces of strategies are differentiable manifolds and the payoff functions are continuously differentiable. We prove the ineffciency of weak local equilibrium in the Pareto sense
67

Resource management in wireless networks

Pillutla, Laxminarayana S. 05 1900 (has links)
This thesis considers resource management issues in wireless sensor networks (WSNs), wireless local area networks (WLANs), and cognitive radio (CR) networks. Since energy is a critical resource in WSNs, we consider energy minimization techniques based on explicit node cooperation and distributed source coding (DSC). The explicit node cooperation based on space time block codes (STBC) improves energy efficiency of WSNs, by reducing the energy consumption per bit of each sensor node. The DSC on the other hand exploits the spatial correlation in WSNs, and thus reduces the data generated in a WSN. For the purpose of our analysis, we model the spatial correlation according to a linear Gauss-Markov model. Through our numerical results, we observe that the node cooperation combined with DSC can improve energy efficiency for many cases of interest. A unique aspect of our work is we obtain important structural results using the concepts from monotone comparative statics. These structural results provide insights into the general design of WSNs. Through our numerical results, we also demonstrate that, the cooperation based transmission can achieve better mutual information (MI)-energy tradeoff than the non-cooperation based transmission scheme. From the perspective of WLANs, we propose a price based approach to regulate the channel occupancy of low rate users, which is known to be the primary cause for low overall throughput in WLANs. Owing to the decentralized nature of WLANs we use non-cooperative game theory as a tool for analysis. Specifically, we use supermodular game theory. Through our analysis, we show that an increase in price leads to an increase in rate of WLAN users. We also prove that the best response dynamics indeed converge to the Nash equilibrium of the underlying non-cooperative game. Through our numerical results, we demonstrate that by proper tuning of the price, the proposed price based approach can lead to an improvement in overall throughput of a WLAN. Finally from the perspective of CR networks, we consider the impact of number of channels captured by a secondary user on its transmission control protocol (TCP) throughput. From our simulation results it was found that, there exists a definite optimal number of channels a secondary user needs to capture, to maximize its TCP throughput. / Applied Science, Faculty of / Electrical and Computer Engineering, Department of / Graduate
68

Využití teorie her v odpadovém hospodářství / Game Theory in Waste Management

Osička, Ondřej January 2016 (has links)
V této práci je vytvořen model rozhodovací situace v odpadovém hospodářství využívající metody teorie her. Model tvoří nekooperativní hra pro reprezentaci konfliktu zpracovatelů odpadu a kooperativní hra pro reprezentaci konfliktu producentů odpadu. Pro konflikt zpracovatelů odpadu je k nalezení strategií při volbě cen na bráně využit koncept Nashovy rovnováhy, takto nalezené stabilní strategie mohou sloužit jako předpověď budoucí situace. Pro zpřesnění množin strategií jsou určeny dolní a horní meze. Pro konflikt producentů odpadu se uvažuje spolupráce všech producentů a určuje se pro ni přerozdělení nákladů pomocí Shapleyho hodnoty a nucleolu. Pro konflikt více producentů jsou vyvinuty aproximační algoritmy pro Shapleyho hodnotu i nucleolus. Tyto algoritmy jsou založeny na předpokladu, že se vzdálení hráči vzájemně neovlivňují. Model je aplikován na situaci v České republice. Pro konflikt zpracovatelů odpadu je nalezen jeden bod Nashovy rovnováhy. Pro konflikt producentů odpadu jsou určeni někteří producenti s vysokým kooperativním potenciálem.
69

Planification multi-agents dans un cadre markovien : les jeux stochastiques à somme générale

Hamila, Mohammed Amine 03 April 2012 (has links)
Planifier les actions d’un agent dans un environnement dynamique et incertain, a été largement étudié et le cadre des processus décisionnels de Markov offre les outils permettant de modéliser et de résoudre de tels problèmes. Le domaine de la théorie des jeux, a permis l’étude des interactions stratégiques entre plusieurs agents pour un jeu donné. Le cadre des jeux stochastiques, est considéré comme une généralisation du domaine des processus décisionnels de Markov et du champ de la théorie des jeux et permet de modéliser des systèmes ayant plusieurs agents et plusieurs états. Cependant, planifier dans unsystème multi-agents est considéré comme difficile, car la politique d’actions de l’agent dépend non seulement de ses choix mais aussi des politiques des autres agents. Le travail que nous présentons dans cette thèse porte sur la prise de décision distribuée dans les systèmes multi-agents. Les travaux existants dans le domaine, permettent la résolution théorique des jeux stochastiques mais imposent de fortes restrictions et font abstraction de certains problèmes cruciaux du modèle. Nous proposons un algorithme de planification décentralisée pour le modèle des jeux stochastiques, d’une part basé sur l’algorithme Value-Iteration et d’autre part basé sur la notion d’équilibre issue de la résolution des jeux matriciels. Afin d’améliorer le processus de résolution et de traiter des problèmes de taille importante, nous recherchons à faciliter la prise de décision et à limiter les possibilités d’actions à chaque étape d’interaction. L’algorithme que nous avonsproposé, a été validé sur un exemple d’interaction incluant plusieurs agents et différentes expérimentations ont été menées afin d’évaluer la qualité de la solution obtenue. / Planning agent’s actions in a dynamic and uncertain environment has been extensively studied. The framework of Markov decision process provides tools to model and solve such problems. The field of game theory has allowed the study of strategic interactions between multiple agents for a given game. The framework of stochastic games is considered as a generalization of the fields of Markov decision process and game theory. It allows to model systems with multiple agents and multiple states. However, planning in a multi-agent system is considered difficult : agent’s decisions depend not only on its actions but also on actions of the other agents. The work presented in this thesis focuses on decision making in distributed multi-agent systems. Existing works in this field allow the theoretical resolution of stochastic games but place severe restrictions and ignore some crucial problems of the model. We propose a decentralized planning algorithm for the model of stochastic games. Our proposal is based on the Value-Iteration algorithm and on the concept of Nash equilibrium. To improve the resolution process and to deal with large problems, we sought to ease decision making and limit the set of joint actions at each stage. The proposed algorithm was validated on a coordination problem including several agents and various experiments were conducted to assess the quality of the resulting solution.
70

A Game Theoretical Approach to Green Communications in Seamless Internet of Things

Tiruchirappalli Narayana Kumar, Venkataramani January 2019 (has links)
No description available.

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