D’après Cisco, le trafic mobile de données augmentera d’un facteur 7 entre 2016 et 2021. Pour faire face à l’augmentation du trafic, les opérateurs mobile dimensionnent le réseau, ce qui s’accompagne d’une augmentation de sa consommation d’énergie et de son empreinte Carbonne. En outre, les marges financières des opérateurs baissent. Ainsi, le revenu global généré par le secteur des télécommunications a connu une baisse de 4% entre 2014 et 2015 d’après l’union internationale des télécommunications (UIT). Ces préoccupations ont suscité l’intérêt de la communauté scientifique pour la réduction de la consommation électrique des réseaux. Des études dans la littérature estiment l’énergie consommée par les services sur les équipements réseaux en se focalisant sur la consommation variable. La consommation énergétique d’un équipement réseau est composée d’une composante fixe et d’une composante variable. Dans cette thèse, nous partageons la responsabilité des catégories de service dans la consommation fixe du réseau en utilisant la valeur de Shapley. Dans un premier temps, nous considérons un réseau d’accès mobile et partageons la responsabilité des catégories de service qu’il fournit dans la consommation fixe. Nous définissons 5 catégories de service, à savoir, le «Streaming», le Web, le téléchargement, la voix et les autres services de données. En outre, nous traitons le cas de figure où certaines catégories de service sont obligatoires. Etant donné la complexité algorithmique de la valeur de Shapley, nous en proposons une forme approchée qui permet d’en réduire considérablement le temps de calcul. Ensuite, nous considérons le réseau de bout-en-bout, c’est-à-dire, l’accès mobile, l’accès fixe, la collecte, le coeur IP, le coeur mobile, les registres et les plateformes de service. Pour chaque segment, nous partageons la responsabilité des catégories de service dans la consommation fixe en appliquant notre modèle de partage basé sur la valeur de Shapley. L’analyse des résultats montre que le service «Streaming» consomme le plus d’énergie quel que soit le segment de réseau considéré, à l’exception des registres. Pour finir, nous traitons de la modélisation de l’efficacité énergétique des catégories de service. Dans un premier temps, nous calculons l’efficacité énergétique des catégories de service étant donné une station de base avec et sans «sleep mode». Ensuite, nous calculons l’efficacité énergétique des catégories de service étant donné un réseau d’accès mobile et considérant les cas avec et sans catégories de service obligatoires. Aussi étudions-nous les conditions pour ne pas détériorer l’efficacité énergétique du réseau au cours du temps en fonction des scénarios de dimensionnement / Internet traffic is growing exponentially. According to Cisco, mobile data traffic will increase sevenfold between 2016 and 2021, growing at a compound annual growth rate (CAGR) of 47%. In order to improve or keep up with users quality of experience (QoE), mobile carriers upgrade the network with additional equipment. As a consequence, the network carbon footprint increases over time, alongside with its energy consumption. In addition, mobile carriers margins are decreasing. Global telecommunication revenues declined by 4% between 2014 and 2015 based on the international telecommunication union (ITU) figures. These concerns fostered a great interest in the research community for reducing networks energy consumption. In this regard, many works in the literature investigate the energy consumed by services on network equipment for optimization purposes notably, focusing on the variable component of energy consumption. Energy consumption of a network equipment is composed of a variable and a fixed components. The variable component is consumed to serve traffic. The fixed component is consumed irrespective of traffic. In this thesis, our objective is to share the responsibility of service categories in the fixed energy consumption. To do so, we use the Shapley value. First, we consider a radio access network and share the responsibility of the service categories it delivers in the fixed energy consumption. The services are classified into five categories, namely, Streaming, Web, Download, Voice and other data services. In addition, we consider the case when some service categories are mandatory to be provided, such as Voice due to legal constraints for instance. Because the Shapley value has a huge computational complexity, we introduce closed-form expressions in order to significantly reduce it. Next, we consider the end-to-end network and all its segments, that is, the mobile access, the fixed access, the collect, the mobile core, the registers, the IP core and the service platforms. For each segment, we share the responsibility of the service categories in the fixed energy consumption with the Shapley-based model introduced in the preceding chapter. We find that Streaming is the service that consumes the most whatever the network segment, except for registers, as it represents the vast majority of Internet traffic. Eventually, we focus on the service categories energy efficiency. First, we consider a base station and compute the services energy efficiency for the cases with and without sleep mode. Then, we consider a radio access network and compute the services energy efficiency with and without a mandatory player. Moreover, we discuss the conditions to not deteriorate the network energy efficiency over time following different upgrade scenarios

This dissertation consists of three papers. In the first paper, I study firms' capital raising decisions in a two-stage signaling game. In the model, firms can issue debt or equity to finance sequentially arriving investment projects. Management is assumed to have an initial information advantage over investors. However, when a firm's decision in the first stage can change investors' beliefs and, consequently, impact the security issuance in the second stage, its optimal choice differs significantly from the strict debt-equity preference in a comparable one-stage model. In equilibrium, a dynamic pecking order arises, suggesting that the information friction can solely explain various aspects of observed corporate financing behavior. The second paper is coauthored with Hans Haller. In this paper, we model how different wealth constraints among investors affect an entrepreneur's way of raising capital, his share of project NPV, and his ownership of the new firm. Combining cooperative and noncooperative approaches, we develop and analyze a bargaining framework and demonstrate cases in which a fair division cannot be achieved when sharing of cost and sharing of return are jointly considered. Our results cover conditions on how the entrepreneur can strategically achieve larger net wealth accumulation, and when he can obtain control of the firm. We further discuss the entrepreneur's preferences on the firm's ownership dispersion level under public financing. The third paper argues that although innovation is costlier than imitation, the incumbent firm is endowed with an advantage of enhancing its product ahead of potential competitors. In a model that connects consumers' utility with firms' production, I show that the incumbent's product enhancement decision can foster the creation of a better product, improve consumers' utility, and deter entrance from competitors. The pace of creative activities is determined by the incumbent's potential of improving its product quality and the nature of product differentiation in the industry. Thus, creative destruction may not manifest itself as new firms replacing the incumbent, but as the incumbent constantly renovating its product. / Doctor of Philosophy / This dissertation consists of three papers. In the first paper I study the adverse selection problem faced by firms in a dynamic information environment, the difference between incentives provided by debt and equity securities, and how different contracts and model settings affect the equilibrium outcome, investment efficiency, and social welfare. The premise of the first paper is that dynamic elements of information asymmetry are key to better understanding how firms raise capital. This study aims to provide a more complete description and improve our understanding of the role of information in capital markets and how asymmetric information might interact with other market frictions. In the second paper I study the origin of the firm and the bargaining problem between entrepreneurs and investors. This second paper intends to provide one possible answer for the question why firms do exist. The main point in the paper is that even when we abstract away from standard frictions like adverse selection or moral hazard, an entrepreneur still has to bargain with investors to raise the required amount of capital. The firm has to be established to enforce the bargaining outcome, which takes the form of an ownership contract, because there is a time gap between conducting the investment and when the proceed can be realized. Another purpose of this second study is to investigate fairness instead of efficiency. Finally, in the third paper, I address the question how and when an incumbent monopolist can deter entry by means of investment in product quality enhancement. In some industries, creative destruction can be frequently observed: Incumbent firms are replaced by new firms that offer slightly different but better products. On the other hand, in a number of industries incumbent firms are at the forefront of innovation and stay ahead of potential entrants. I consider a model that allows for the latter fact combined with another frequent fact: that potential entrants more or less copy the incumbent's prior product, regardless of existence and enforcement of intellectual property rights. This third paper offers predictions on product innovation and market failure across firms and industries.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Um die Auswirkung der Liberalisierung der EU-Erdgasmärkte auf die Macht der Marktteilnehmer zu studieren, entwickeln wir ein disaggregiertes Modell der eurasischen Erdgasversorgung. Wir modellieren die Abhängigkeiten zwischen den Spielern als kooperatives Spiel und berücksichtigen verschiedene Lösungen: den Shapley-Wert, den Nukleolus und den Kern. Im Kapitel 1 untersuchen wir die regionalen Auswirkungen der Liberalisierung des Zugangs zu den Übertragungsnetzen, sowie die Anreize für Fusionen und Kartelle. Im Kapitel 2 untersuchen wir die Auswirkung der Liberalisierung auf die Machtbalance zwischen den lokalen Champions, den Kunden und den Produzenten außerhalb EU. Wir unterscheiden zwischen zwei Schritten der Reform: 1.die Öffnung des Zugangs zu den Übertragungsnetzen und 2.die Öffnung des Zugangs zu den Vertriebssystemen. Für den Shapley-Wert finden wir geringe und heterogene Effekte des ersten Schritts. Die Auswirkungen des zweiten Schritts sind viel größer und ergeben ein klares Muster: alle lokalen Champions verlieren, während alle Kunden und alle externen Produzenten gewinnen. Da ein Drittel der Verluste der Champions innerhalb EU zu den Spielern im Ausland abfließt, können die aktuellen Reformen die Dominanz der bereits starken externen Produzenten verbessern. Wenn wir den Nukleolus heranziehen, profitieren die Produzenten außerhalb EU von der vollen Liberalisierung hingegen nicht. Im Kapitel 3 untersuchen wir die Beziehungen zwischen Shapley-Wert, Nukleolus und Kern. Für unser Modell ist der Shapley-Wert nie im Kern. Um ein Maß der Instabilität von Auszahlungen, die nicht im Kern liegen, zu erhalten, schlagen wir eine Erweiterung des starken epsilon-Kerns vor und betrachten 3 Metriken. Wir finden, daß die Liberalisierung die Instabilität des Shapley-Werts erhöht. Wir zeigen, daß die Liberalisierung den Kern komprimiert. Die Auswirkung auf den Nukleolus korrespondiert jedoch nicht immer mit der Verschiebung von Minimal- und Maximalwerten der Spieler im Kern. / To study the impact of the liberalization of EU natural gas markets on the power of market players we develop a disaggregated model of the Eurasian natural gas supply system. We model interdependenices among the players as a cooperative game for which we consider various solutions: the Shapley value, the nucleolus and the core. In the first paper we study regional impact of liberalization of access to transmission networks, incentives for mergers and cartels. In the second paper we study the impact of liberalization on the balance of power between ''local champions'', customers, and outside producers, such as Russian Gazprom. We distinguish between two steps of the reform: 1. opening access to transit pipes and 2. opening access to distribution systems, hence customers. Using the Shapley value, we find a modest and rather heterogeneous impact from the first step. The impact of the second step is much larger and yields a clear pattern: all local champions lose, while all customers and all outside producers gain. As one third of the losses of champions within EU leaks to players abroad, current reforms might enhance the dominance of already powerful outside producers. When we apply the nucleolus, in contrast, full liberalization does not benefit outside producers at all. In the third paper we focus on the relation of the Shapley value and the nucleolus to the core. For our model the Shapley value is never in the core. To evaluate the degree of instability of a payoff allocation which is not in the core, we propose an extension of the strong epsilon-core and consider three metrics. We find that liberalization increases the degree of instability of the Shapley value for all metrics. We show that liberalization compresses the core, but not always the nucleolus corresponds well to the shifts in the minimal and maximal values of players in the core.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

One problem in cooperative game theory is to model situations when two players refuse to cooperate (or the problem of quarreling members in coalitions). One example of such exclusions is the coalition statements of parliamentary parties. Other situations in which incompatible players affect the outcome are teams in firms and markets, for example. To model these exclusions in cooperative game theory, the excluded coalitions value ( φE value) was introduced. This value is based on the Shapley value and takes into account that players exclude coalitions with other players. In this article, we deduce some properties of this new value. After some general results, we analyze the apex game that could be interpreted as a team situation and the glove game that models markets where sellers and buyers deal. For team situations, we show that all employees have a common interest for cooperation. On asymmetric markets, excluding coalitions affect the market players of the scarce side to a higher extent.

One problem in cooperative game theory is to model situations when two players refuse to cooperate (or the problem of quarreling members in coalitions). One example of such exclusions is the coalition statements of parliamentary parties. Other situations in which incompatible players affect the outcome are teams in firms and markets, for example. To model these exclusions in cooperative game theory, the excluded coalitions value ( φE value) was introduced. This value is based on the Shapley value and takes into account that players exclude coalitions with other players. In this article, we deduce some properties of this new value. After some general results, we analyze the apex game that could be interpreted as a team situation and the glove game that models markets where sellers and buyers deal. For team situations, we show that all employees have a common interest for cooperation. On asymmetric markets, excluding coalitions affect the market players of the scarce side to a higher extent.

Abstract The aim of this thesis is to devise new paradigms on radio resource sharing including cache-enabled virtualized large cellular networks for mobile network operators (MNOs). Also, self-organizing resource allocation for small cell networks is considered. In such networks, the MNOs rent radio resources from the infrastructure provider (InP) to support their subscribers. In order to reduce the operational costs, while at the same time to significantly increase the usage of the existing network resources, it leads to a paradigm where the MNOs share their infrastructure, i.e., base stations (BSs), antennas, spectrum and edge cache among themselves. In this regard, we integrate the theoretical insights provided by stochastic geometrical approaches to model the spectrum and infrastructure sharing for large cellular networks. In the first part of the thesis, we study the non-orthogonal multi-MNO spectrum allocation problem for small cell networks with the goal of maximizing the overall network throughput, defined as the expected weighted sum rate of the MNOs. Each MNO is assumed to serve multiple small cell BSs (SBSs). We adopt the many-to-one stable matching game framework to tackle this problem. We also investigate the role of power allocation schemes for SBSs using Q-learning. In the second part, we model and analyze the infrastructure sharing system considering a single buyer MNO and multiple seller MNOs. The MNOs are assumed to operate over their own licensed spectrum bands while sharing BSs. We assume that multiple seller MNOs compete with each other to sell their infrastructure to a potential buyer MNO. The optimal strategy for the seller MNOs in terms of the fraction of infrastructure to be shared and the price of the infrastructure, is obtained by computing the equilibrium of a Cournot-Nash oligopoly game. Finally, we develop a game-theoretic framework to model and analyze a cache-enabled virtualized cellular networks where the network infrastructure, e.g., BSs and cache storage, owned by an InP, is rented and shared among multiple MNOs. We formulate a Stackelberg game model with the InP as the leader and the MNOs as the followers. The InP tries to maximize its profit by optimizing its infrastructure rental fee. The MNO aims to minimize the cost of infrastructure by minimizing the cache intensity under probabilistic delay constraint of the user (UE). Since the MNOs share their rented infrastructure, we apply a cooperative game concept, namely, the Shapley value, to divide the cost among the MNOs. / Tiivistelmä Tämän väitöskirjan tavoitteena on tuottaa uusia paradigmoja radioresurssien jakoon, mukaan lukien virtualisoidut välimuisti-kykenevät suuret matkapuhelinverkot matkapuhelinoperaattoreille. Näiden kaltaisissa verkoissa operaattorit vuokraavat radioresursseja infrastruktuuritoimittajalta (InP, infrastructure provider) asiakkaiden tarpeisiin. Toimintakulujen karsiminen ja samanaikainen olemassa olevien verkkoresurssien hyötykäytön huomattava kasvattaminen johtaa paradigmaan, jossa operaattorit jakavat infrastruktuurinsa keskenään. Tämän vuoksi työssä tutkitaan teoreettisia stokastiseen geometriaan perustuvia malleja spektrin ja infrastruktuurin jakamiseksi suurissa soluverkoissa. Työn ensimmäisessä osassa tutkitaan ei-ortogonaalista monioperaattori-allokaatioongelmaa pienissä soluverkoissa tavoitteena maksimoida verkon yleistä läpisyöttöä, joka määritellään operaattoreiden painotettuna summaläpisyötön odotusarvona. Jokaisen operaattorin oletetaan palvelevan useampaa piensolutukiasemaa (SBS, small cell base station). Työssä käytetään monelta yhdelle -vakaata sovituspeli-viitekehystä SBS:lle käyttäen Q-oppimista. Työn toisessa osassa mallinnetaan ja analysoidaan infrastruktuurin jakamista yhden ostaja-operaattorin ja monen myyjä-operaattorin tapauksessa. Operaattorien oletetaan toimivan omilla lisensoiduilla taajuuksillaan jakaen tukiasemat keskenään. Myyjän optimaalinen strategia infrastruktuurin myytävän osan suuruuden ja hinnan suhteen saavutetaan laskemalla Cournot-Nash -olipologipelin tasapainotila. Lopuksi, työssä kehitetään peli-teoreettinen viitekehys virtualisoitujen välimuistikykenevien soluverkkojen mallintamiseen ja analysointiin, missä InP:n omistama verkkoinfrastruktuuri vuokrataan ja jaetaan monen operaattorin kesken. Työssä muodostetaan Stackelberg-pelimalli, jossa InP toimii johtajana ja operaattorit seuraajina. InP pyrkii maksimoimaan voittonsa optimoimalla infrastruktuurin vuokrahintaa. Operaattori pyrkii minimoimaan infrastruktuurin hinnan minimoimalla välimuistin tiheyttä satunnaisen käyttäjän viive-ehtojen mukaisesti. Koska operaattorit jakavat vuokratun infrastruktuurin, työssä käytetään yhteistyöpeli-ajatusta, nimellisesti, Shapleyn arvoa, jakamaan kustannuksia operaatoreiden kesken.

This work concentrates on the study of mathematical models of human behaviour in dynamic games; in particular games with aspects of cooperation, implementation of a model and experimentation with the model. The game DarkElf was chosen for this project. It is a strategic, turn based game with economic and military features, where the decisions made by players are simultaneously implemented at a predetermined time.