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It is known that quantum strategies change the range of possible payoffs for the players in the prisoner's dilemma. In this paper, we examine the effect of the degree of entanglement in determining the payoffs. When both players play quantum strategies, we show that the payoff for both players is unaffected by the entanglement value and it leads to a new Nash equilibrium.

Increasingly used in online auctions, buyout prices allow bidders to instantly purchase the item listed. We distinguish two types: a temporary buyout option disappears if a bid above the reserve price is made; a permanent one remains throughout the auction or until it is exercised. In a model featuring time-sensitive bidders with uniform valuations and Poisson arrivals but endogenous bidding times, we focus on finding temporary and permanent buyout prices maximizing the seller's discounted revenue, and examine the relative benefit of using each type of option in various environments. We characterize equilibrium bidder strategies in both cases and then solve the problem of maximizing seller's utility by simulation. Our numerical experiments suggest that buyout options may significantly increase a seller’s revenue. Additionally, while a temporary buyout option promotes early bidding, a permanent option gives an incentive to the bidders to bid late, thus leading to concentrated bids near the end of the auction. / Singapore-MIT Alliance (SMA)

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For zero-sum games, we have efficient solution techniques. Unfortunately, there are interesting games that are too large to solve. Here, a popular approach is to solve an abstract game that models the original game. We assume that more accurate the abstract games result in stronger strategies. There is substantial evidence to support this assumption. We begin by formalizing abstraction and refinement, a notion of expressive power for abstractions. We then show the assumption fails to hold under two criteria. The first is exploitability, which measures performance in the worst-case. The second is called the domination value, which measures how many mistakes a strategy makes. Despite these pathologies, we notice that larger strategies tend to make fewer mistakes and perform better in tournaments. Finally, we introduce strategy grafting, a technique that uses sub-game decomposition, which allow us to create good strategies in much larger spaces than previously possible.

The Internet has a loosely hierarchical structure. At the top of the hierarchy are the backbones, also called Internet Access Providers (hereafter IAPs). The second layer of the hierarchy is comprised of Internet Service Providers (hereafter ISPs). At the bottom of the hierarchy are the end users, consumers, who browse the web, and websites. To provide access to the whole Internet, the providers must interconnect with each other and share their network infrastructure. Two main forms of interconnection have emerged — peering under which the providers carry each other's traffic without any payments and transit under which the downstream provider pays the upstream provider a certain settlement payment for carrying its traffic. This dissertation develops three game theoretical models to describe the interconnection agreements among the providers, and analysis of those models from two alternative modeling perspectives: a purely non-cooperative game and a network perspective. There are two original contributions of the dissertation. First, we model the formation of peering/transit contracts explicitly as a decision variable in a non-cooperative game, while the current literature does not employ such modeling techniques. Second, we apply network analysis to examine interconnection decisions of the providers, which yields much realistic results. Chapter 1 provides a brief description of the Internet history, architecture and infrastructure as well as the economic literature. In Chapter 2 we develop a model, in which IAPs decide on private peering agreements, comparing the benefits of private peering relative to being connected only through National Access Points (hereafter NAPs). The model is formulated as a multistage game. Private peering agreements reduce congestion in the Internet, and so improve the quality of IAPs. The results show that even though the profits are lower with private peerings, due to large investments, the network where all the providers privately peer is the stable network. Chapter 3 discusses the interconnection arrangements among ISPs. Intra-backbone peering refers to peering between ISPs connected to the same backbone, whereas inter-backbone peering refers to peering between ISPs connected to different backbones. We formulate the model as a two-stage game. Peering affects profits through two channels - reduction of backbone congestion and ability to send traffic circumventing congested backbones. The relative magnitude of these factors helps or hinders peering. In Chapter 4 we develop a game theoretic model to examine how providers decide who they want to peer with and who has to pay transit. There is no regulation with regard to interconnection policies of providers, though there is a general convention that the providers peer if they perceive equal benefits from peering, and have transit arrangements otherwise. The model discusses a set of conditions, which determine the formation of peering and transit agreements. We argue that market forces determine the terms of interconnection, and there is no need for regulation to encourage peering. Moreover, Pareto optimum is achieved under the transit arrangements. / Ph. D.

Denna kandidatuppsats bemöter frågan om väljarbeteende i allmänna val; huruvida strategiskt röstande (taktikröstning) är ett förekommande fenomen i val till svenska kommunfullmäktige eller ej och i så fall vilka faktorer som ligger bakom strategiskt röstande. En underförstådd tes bakom väljarbeteende är att röstberättigade röstar i enlighet med deras partipreferens utifrån en rad underliggande orsaker, såsom sakpolitik, partifärg, ideologi och organisationsstruktur. Dock har viss forskning uppstått som tyder på att somliga väljare agerar konsekvent och röstar utifrån bästa möjliga utdelning (payoff), snarare än direkta skäl. Dessa indirekta skäl kan röra sig om partiernas valallianser med övriga partier, något som alltid inte uppskattas av väljarna. Under senare halvan av 1900-talet har studier kring väljarbeteende uppmärksammats av statsvetare och beteendevetare. En av de mest omnämnda publikationerna inom vetenskapen är undertecknad den amerikanska ekonomen Anthony Downs som genom sin bok An Economic Theory of Democracy (1957) har undersökt relationen mellan politiska kandidater och väljare. Uppsatsen kommer presentera för läsaren tidigare studier inom detta specifika forskningsområde samt en nutidshistorisk överblick i s.k. oheliga allianser. Resultatet kommer visa på partisamverkans tydliggjorda betydelse i hur kommunmedborgarna röstar i allmänna val.

The dissertation deals with the interplay of fiscal and monetary policy in face of uncertainty about the estimation of the true output gap. Theoretical framework of the dissertation set this interplay of monetary and fiscal policy into the realm of game theory, in particularly non-cooperative games of the Nash and Stackelberg equilibrium, respectively. The theoretical framework continued with a description of various methods used for estimation of potential output and output gap, with a special emphasis on methods used in both the Czech National Bank and Czech Ministry of Finance. In the applied part of the dissertation, I studied the interplay of monetary and fiscal policy in the case of Czech economy facing an uncertainty about the estimation of the true output gap. I studied the impact of this interplay on major macroeconomic variables and I tried to determine, which of these two policies plays the role of a leader and which plays the role of a follower in the case of Czech economic environment.

Cette thèse présente de nouvelles techniques pour les Constraint Games.La manière de résoudre un Constraint Game est repensée en terme de propagation de contraintes.Les préférences des joueurs sont maintenant considérées comme des contraintes globales permettant une intégration transparente dans les solveurs de contraintes ainsi que d'améliorer l'efficacité du framework.Notre nouveau solveur ConGA est diffusé en open source.Celui-ci est plus rapide que les travaux connexes et est capable de trouver tous les équilibres de Nash, et cela même dans des jeux avec 200 joueurs voir 2000 pour certains jeux graphiques.Grâce à cette perspective, le framework a pu être utilisé pour résoudre un problème de routage dans le domaine des télécommunications. Les aspects centralisé et décentralisé ont été étudiés.La comparaison de ces derniers est très importante pour évaluer la qualité de service dans les applications multi-utilisateurs. L'évaluation de cette dernière peut être très coûteuse, c'est pourquoi nous proposons plusieurs techniques permettant d'améliorer la résolution de ce problème et ainsi d'améliorer la résolution du problème. / This thesis revisits the Constraint games framework by rethinking their solving technique in terms of constraint propagation.Players preferences are considered as global constraints making transparently the integration in constraints solvers.It yields not only a more elegant but also a more efficient framework.We release our new solver ConGA in open source.Our new complete solver is faster than previous state-of-the-art and is able to find all pure Nash equilibrium for some problems with 200 players or even with 2000 players in graphical games.This new perspective enables us to tackle real-worlds Telecommunication problems.This problem is solved with a centralized perspective and a decentralized one.The comparison of the two last approaches is really important to evaluate the quality of service in multi-users application, but computationally consuming.That is why, we propose new techniques in order to improve the resolution process.

In this thesis we consider a set of mobile users that employ cloud-based computation offloading. In computation offloading, user energy consumption can be decreased by uploading and executing jobs on a remote server, rather than processing the jobs locally. In order to execute jobs in the cloud however, the user uploads must occur over a base station channel which is shared by all of the uploading users. Since the job completion times are subject to hard deadline constraints, this restricts the feasible set of jobs that can be remotely processed, and may constrain the users ability to reduce energy usage. The system is modelled as a competitive game in which each user is interested in minimizing its own energy consumption. The game is subject to the real-time constraints imposed by the job execution deadlines, user specific channel bit rates, and the competition over the shared communication channel. The thesis shows that for a variety of parameters, a game where each user independently sets its offloading decisions always has a pure Nash equilibrium, and a Gauss-Seidel method for determining this equilibrium is introduced. Results are presented which illustrate that the system always converges to a Nash equilibrium using the Gauss-Seidel method. Data is also presented which show the number of Nash equilibria that are found, the number of iterations required, and the quality of the solutions. We find that the solutions perform well compared to a lower bound on total energy performance. / Thesis / Master of Applied Science (MASc)