Trust and speech are both essential aspects of human interaction. On the one hand, trust is necessary for vocal communication to be meaningful. On the other hand, humans have developed a way to infer someone’s trustworthiness from their voice, as well as to signal their own. Yet, research on trustworthiness attributions to speakers is scarce and contradictory, and very often uses explicit data, which do not predict actual trusting behaviour. However, measuring behaviour is very important to have an actual representation of trust. This thesis contains 5 experiments aimed at examining the influence of various voice characteristics — including accent, prosody, emotional expression and naturalness — on trusting behaviours towards virtual players and robots. The experiments have the "investment game"—a method derived from game theory, which allows to measure implicit trustworthiness attributions over time — as their main methodology. Results show that standard accents, high pitch, slow articulation rate and smiling voice generally increase trusting behaviours towards a virtual agent, and a synthetic voice generally elicits higher trustworthiness judgments towards a robot. The findings also suggest that different voice characteristics influence trusting behaviours with different temporal dynamics. Furthermore, the actual behaviour of the various speaking agents was modified to be more or less trustworthy, and results show that people’s trusting behaviours develop over time accordingly. Also, people reinforce their trust towards speakers that they deem particularly trustworthy when these speakers are indeed trustworthy, but punish them when they are not. This suggests that people’s trusting behaviours might also be influenced by the congruency of their first impressions with the actual experience of the speaker’s trustworthiness — a "congruency effect". This has important implications in the context of Human–Machine Interaction, for example for assessing users’ reactions to speaking machines which might not always function properly. Taken together, the results suggest that voice influences trusting behaviour, and that first impressions of a speaker’s trustworthiness based on vocal cues might not be indicative of future trusting behaviours, and that trust should be measured dynamically.

Neste projeto analisamos jogos de formação de redes que são variantes do problema da floresta de Steiner, nos quais indivíduos desejam conectar conjuntos de vértices terminais em um grafo de forma a minimizar seus custos, podendo dividir o custo das arestas com os demais participantes. Estudamos como o método de divisão de custos influencia na existência e na qualidade dos equilíbrios desses jogos em comparação com o valor da solução ótima centralizada. / In this project we analyze network formation games that are variants of the Steiner forest problem, in which individuals wish to connect sets of terminal vertices of a graph in a way that minimizes their costs, being able to divide the cost of an edge with the other participants. We study how the method used to divide the costs influences the existence and quality of the equilibria of these games in relation to the centralized optimal solution.

O presente trabalho busca apresentar uma aplicação da teoria dos jogos, de modo a complementar a literatura que utiliza esse referencial teórico e alcançar conclusões pertinentes que desafiam o senso comum. O assunto trabalhado são os debates políticos televisivos e o excesso de acusações realizadas pelos participantes. Através de premissas e expectativas dos jogos não cooperativos, que foram aplicadas sobre os debates de 2º turno das eleições presidenciais de 1989, 2006, 2010 e 2014, a hipótese de que a razão de tal comportamento é a própria organização do jogo, e não uma eventual falta de propostas a serem apresentadas pelos políticos, não é refutada empiricamente. Além disso, sugestões de mudanças de regras desses programas são realizadas, de modo que seu objetivo principal, a exposição de planos de governo, passe a ser atingido. / The present work seeks to present an application of the Game Theory, in order to complement the literature that uses this theoretical reference and to reach pertinent conclusions that defy common sense. The topic that is going to be studied are the televised political debates and the excess of accusations made by the participants. Through assumptions and expectations of non-cooperative games, that were applied to the 2nd round debates of the 1989, 2006, 2010 and 2014 presidential elections, the hypothesis that the reason for such behavior is the organization of the game, not an eventual lack of proposals by the political parties, is not empirically refuted. In addition, suggestions for changes in the rules of these programs are made, in order to ensure that the primary debates\' goal of exposing government plans is reached.

本論文包含四個部分。每一部分我們演示一個在共同演化網絡中的個體為本(agent-based)模型。第二章是不滿適應雪堆博奕(DASG)的廣泛化。第三章是自省適應(self-questioning adaptive)雪堆博奕。第四章是共同演化選民模型的廣泛化。第五章是有三個互相克制的角色的適應性石頭-布-剪刀(ARPS)模型。在這些模型中，適應行為導致共同演化過程發生。我們以電算模擬及理論方法研究這些模型。我們的目標是建立一個可應用於不同共同演化網絡的一般分析框架。 / 在第二章及第四章，我們將Gräser等人的DASG及Vazquez等人的共同演化選民模型從一個控制參數推廣到二個獨立的控制參數。在他們的工作中，根據網絡的結構定義了一些相，而且發展了平均場理論。而在廣泛化的情況下，在已伸延的相空間上，我們也定義了一些相及發展了一些廣泛化的平均場理論。在廣泛化DASG中，我們以考慮在相邊界附近的最終生存形態(last surviving patterns)以解釋相邊界的電算模擬結果。 / 在第三章，我們提出及研究一個以誘惑驅動的雪堆博奕。該更新機制被稱為自省機制(self-questioning mechanism)。我們給出模擬及理論結果，也討論了該些結果的物理意義。 / 在第五章，我們推廣我們的研究至有三個策略的遊戲。我們提出及研究了一個ARPS模型，其中每個個體採用三個互相克制的策略的其中之一。每個個體以概率 p來重連不理想的連結或以概率 (1 - p)改變自身的策略以適應其周遭環境。我們研究了網絡於不同的 p值在穩定態的行為及定義 了一些相。我們研究兩個選取重連對象的方法，分別對應於隨機選取及刻意選取重連對象，也解釋了得出的結果。我們在有關穩定勝利、平手及失敗概率的研究中及哪種個體可以有更高的勝利概率的研究中得出了有趣的結果。我們也研究了結果如何取決於初始條件。 / 在不同的模型中，理論方程均建立於相似的想法上。理論結果得出模擬結果的主要特性，包括出現了不同的相。該分析方法被證明了在本論文中對不同的模型也有效，而該方法也可被應用於很多其他共同演化網絡上。 / This thesis consists of four parts. In each part, we present results of an agent-based model of co-evolving network. Chapter 2 deals with a generalization of the Dissatisfied Adaptive Snowdrift Game (DASG) and Chapter 3 covers the self-questioning adaptive snowdrift game. Chapter 4 discusses a generalization of a co-evolving voter model. Chapter 5 gives the results on a cyclic three-character Adaptive Rock-Paper-Scissor (ARPS) game. The adaptive actions give rise to co-evolving processes in these models. These models are studied both numerically and analytically. An objective here is to establish a general analytic framework that is applicable to different models of co-evolving networks. / In Chapters 2 and 4, we generalize two existing models -the DASG of Gräser et al. and the co-evolving voter model of Vazquez et al. -from a single control parameter to two independent parameters. Different phases were identified according to the network structure and mean-field theories were developed in the previous work. With the expanded phase space in our generalized models, we identified different phases and provided a generalized mean-field approach. The phase boundaries in the generalized DASG can be explained by considering the last surviving patterns in the vicinity of the transition between two phases. / In Chapter 3, we propose and study a co-evolving snowdrift game in which the adaptive actions are driven by the desire to enhance winning. The updating scheme is called the self-questioning mechanism. We present simulation and theoretical results, and provide physical meaning to the results. / In Chapter 5, we extend our study to three-strategy games. An ARPS model in which each agent uses one of three strategies that dominate each other cyclically is proposed and studied. Each agent adapts his local environment by rewiring an un-favourable link with a probability p or switching his strategy with a probability 1-p. As p varies, the behaviour of the network in the steady state is studied and dierent phases are identified. Two dierent schemes corresponding to selecting the rewiring target randomly and intentionally are studied and the results are explained. Interesting results are also found in the probabilities of winning, losing and drawing in the steady state; and the type of agents that have a higher winning probability. The dependence on the initial distribution of the three strategies among the agents is also studied. / The analytic equations presented for each model in the thesis are established on similar ideas. The analytic results capture the main features in the simulation results, including the emergence of dierent phases. The analytic approach, proven to be useful through different models in this thesis, can be applied to a wide class of other co-evolving network models. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Choi, Chi Wun / 個體為本共同演化網絡的研究 / 蔡至桓. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2012. / Includes bibliographical references (leaves 114-116). / Abstracts also in Chinese. / Choi, Chi Wun / Ge ti wei ben gong tong yan hua wang luo de yan jiu / Cai Zhihuan. / Abstract --- p.i / 摘要 --- p.iii / Acknowledgements --- p.v / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Introduction --- p.1 / Chapter 1.2 --- Review --- p.5 / Chapter 1.2.1 --- Network and basic graph properties --- p.5 / Chapter 1.2.2 --- Two-person games --- p.6 / Chapter 2 --- Generalization of Dissatisfied-Adaptive Snowdrift Game (DASG) --- p.8 / Chapter 2.1 --- Introduction --- p.8 / Chapter 2.2 --- Dissatisfied-Adaptive model --- p.12 / Chapter 2.3 --- Previous work --- p.14 / Chapter 2.4 --- Generalized Dissatisfied-Adaptive model --- p.16 / Chapter 2.5 --- Simulation results --- p.17 / Chapter 2.6 --- Theoretical analysis --- p.19 / Chapter 2.6.1 --- Mean-Field approach --- p.19 / Chapter 2.6.2 --- Theoretical results --- p.22 / Chapter 2.7 --- Last surviving patterns --- p.25 / Chapter 2.7.1 --- Observing the last surviving patterns --- p.25 / Chapter 2.7.2 --- Applying the theory using extracted information from simulations --- p.26 / Chapter 2.7.3 --- Further development of the theory --- p.28 / Chapter 2.7.4 --- Results of the theory --- p.30 / Chapter 2.8 --- Dependence on initial conditions and mean degree --- p.32 / Chapter 2.9 --- Conclusion --- p.34 / Chapter 3 --- Self-questioning Adaptive SG --- p.36 / Chapter 3.1 --- Introduction --- p.36 / Chapter 3.2 --- Self-questioning adaptive SG with control parameter r --- p.39 / Chapter 3.2.1 --- Model --- p.39 / Chapter 3.2.2 --- Results --- p.40 / Chapter 3.3 --- Self-questioning adaptive SG with control parameters r and h --- p.42 / Chapter 3.3.1 --- Model --- p.42 / Chapter 3.3.2 --- Results --- p.43 / Chapter 3.4 --- Conclusion --- p.45 / Chapter 4 --- Generalization of co-evolving voter model --- p.46 / Chapter 4.1 --- Introduction --- p.46 / Chapter 4.2 --- Co-evolving voter model --- p.49 / Chapter 4.3 --- Previous work --- p.50 / Chapter 4.4 --- Simulation results --- p.52 / Chapter 4.4.1 --- Results of macroscopic quantities --- p.52 / Chapter 4.4.2 --- Results of trajectories by simulations --- p.54 / Chapter 4.4.3 --- The largest component --- p.55 / Chapter 4.4.4 --- Short Summary --- p.56 / Chapter 4.5 --- Theoretical analysis --- p.57 / Chapter 4.5.1 --- Mean-Field approach --- p.57 / Chapter 4.5.2 --- Theoretical results --- p.59 / Chapter 4.6 --- Dependence on initial conditions and mean degree --- p.60 / Chapter 4.6.1 --- Results for different mean degrees --- p.60 / Chapter 4.6.2 --- Results for different initial conditions --- p.61 / Chapter 4.7 --- Conclusion --- p.63 / Chapter 5 --- Adaptive Rock-Paper-Scissors games --- p.64 / Chapter 5.1 --- Introduction --- p.64 / Chapter 5.2 --- Adaptive Rock-Paper-Scissors Model --- p.67 / Chapter 5.3 --- Simulation results --- p.70 / Chapter 5.4 --- Theoretical analysis --- p.73 / Chapter 5.4.1 --- Simplifications by threefold-symmetry --- p.73 / Chapter 5.4.2 --- Changes in local quantities --- p.74 / Chapter 5.4.3 --- Mean-Field approach --- p.75 / Chapter 5.4.4 --- Theoretical results --- p.80 / Chapter 5.5 --- Dependence on mean degree --- p.82 / Chapter 5.6 --- Oriented rewiring method --- p.83 / Chapter 5.7 --- Probabilities of winning, drawing and losing --- p.85 / Chapter 5.7.1 --- Average probabilities of winning, drawing and losing in the steady state --- p.85 / Chapter 5.7.2 --- Degree distribution and the distributions of the probabilities --- p.86 / Chapter 5.7.3 --- Brief explanation --- p.88 / Chapter 5.7.4 --- Results for a larger μ --- p.89 / Chapter 5.7.5 --- Short summary --- p.90 / Chapter 5.8 --- Results for general initial conditions --- p.92 / Chapter 5.8.1 --- Coupled dynamical equations --- p.92 / Chapter 5.8.2 --- Trajectories of the macroscopic quantities --- p.94 / Chapter 5.8.3 --- Phases and theoretical ternary phase diagrams --- p.96 / Chapter 5.9 --- Conclusion --- p.98 / Chapter 6 --- Summary --- p.100 / Chapter A --- Coupled dynamical equations for Self-questioning adaptive SG --- p.104 / Chapter B --- Theoretical results for Self-questioning adaptive SG with control parameters r and h --- p.106 / Chapter C --- Derivations of Mean-Field equations in ARPS model --- p.108 / Chapter D --- Derivations of Mean-Field equations for the oriented rewiring method in ARPS model --- p.111 / Bibliography --- p.114

by Lo Ting Shek = 複雜適應系統中的個體為本模型 / 盧庭碩. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 105-107). / Text in English; abstracts in English and Chinese. / by Lo Ting Shek = Fu za shi ying xi tong zhong de ge ti wei ben mo xing / Lu Tingshuo. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Minority game --- p.9 / Chapter 2.1 --- The model --- p.9 / Chapter 2.2 --- Review on selected work on MG --- p.13 / Chapter 2.2.1 --- Market efficiency and Phase transition --- p.13 / Chapter 2.2.2 --- Crowd effect in MG --- p.17 / Chapter 2.2.3 --- Hamming distance between strategies --- p.19 / Chapter 2.2.4 --- Statistical mechanics of systems with heterogeneous agents --- p.21 / Chapter 3 --- Theory of the minority game --- p.23 / Chapter 3.1 --- Formalism --- p.23 / Chapter 3.2 --- Discussion --- p.31 / Chapter 4 --- Evolutionary Minority Game --- p.33 / Chapter 4.1 --- Model --- p.33 / Chapter 4.2 --- Results --- p.36 / Chapter 4.3 --- Discussion --- p.38 / Chapter 5 --- Theory of the Evolutionary Minority game --- p.43 / Chapter 5.1 --- The theory of D'hulst and Rodgers [1] --- p.44 / Chapter 5.1.1 --- Discussion on the D'hulst and Rodgers's theory --- p.51 / Chapter 5.2 --- Theory of EMG [2] --- p.54 / Chapter 5.2.1 --- Formalism --- p.55 / Chapter 5.2.2 --- Results --- p.60 / Chapter 5.2.3 --- Discussion --- p.66 / Chapter 6 --- Evolutionary Minority Game with arbitrary cutoffs --- p.68 / Chapter 6.1 --- Model --- p.68 / Chapter 6.2 --- Results --- p.69 / Chapter 6.3 --- Theory --- p.76 / Chapter 6.4 --- Discussion --- p.85 / Chapter 7 --- Evolutionary minority game with heterogeneous strategy distribution --- p.88 / Chapter 7.1 --- Model --- p.89 / Chapter 7.2 --- Results --- p.90 / Chapter 7.3 --- Discussion --- p.99 / Chapter 8 --- Conclusion --- p.103

by Tsang Wai-Hung. / Thesis sumbitted in: December 1997. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1998. / Includes bibliographical references (leaves 46-48). / Abstract also in Chinese. / Acknowledgements --- p.ii / Abstract --- p.iii / Table of Contents --- p.v / Chapter / Chapter I. --- Introduction --- p.1 / Chapter II. --- Model and Main Results --- p.8 / Chapter III. --- Proofs --- p.16 / Chapter IV. --- Correlated Equilibrium and Myopic-Consistent Equilibrium --- p.29 / Chapter V. --- Application --- p.33 / Chapter VI. --- Conclusion --- p.36 / Chapter VII. --- Appendix --- p.37 / Reference --- p.46

This dissertation studies several problems centered around developing a better understanding of the energy efficiency of cooperative wireless communication systems. Cooperative communication is a technique where two or more nodes in a wireless network pool their antenna resources to form a "virtual antenna array". Over the last decade, researchers have shown that many of the benefits of real antenna arrays, e.g. spatial diversity, increased range, and/or decreased transmission energy, can be achieved by nodes using cooperative transmission. This dissertation extends the current body of knowledge by providing a comprehensive study of the energy efficiency of two-source cooperative transmission under differing assumptions about channel state knowledge, cooperative protocol, and node selfishness. The first part of this dissertation analyzes the effect of channel state information on the optimum energy allocation and energy efficiency of a simple cooperative transmission protocol called "orthogonal amplify-and-forward" (OAF). The source nodes are required to achieve a quality-of service (QoS) constraint, e.g. signal to noise ratio or outage probability, at the destination. Since a QoS constraint does not specify a unique transmit energy allocation when the nodes use OAF cooperative transmission, minimum total energy strategies are provided for both short-term and long-term QoS constraints. For independent Rayleigh fading channels, full knowledge of the channel state at both of the sources and at the destination is shown to significantly improve the energy efficiency of OAF cooperative transmission as well as direct (non-cooperative) transmission. The results also demonstrate how channel state knowledge affects the minimum total energy allocation strategy. Under identical channel state knowledge assumptions, the results demonstrate that OAF cooperative transmission tends to have better energy efficiency than direct transmission over a wide range of channel conditions. The second part of this dissertation focuses on the development of an opportunistic hybrid cooperative transmission protocol that achieves increased energy efficiency by not only optimizing the resource allocation but also by selecting the most energy efficient cooperative transmission protocol from a set of available protocols according to the current channel state. The protocols considered in the development of the hybrid cooperative transmission protocol include compress-and-forward (CF), estimate-and-forward (EF), non-orthogonal amplify-and-forward (NAF), and decode-and-forward (DF). Instantaneous capacity results are analyzed under the assumption of full channel state knowledge at both of the sources and the destination node. Numerical results are presented showing that the delay limited capacity and outage probability of the hybrid cooperative transmission protocol are superior to that of any single protocol and are also close to the cut-set bound over a wide range of channel conditions. The final part of this dissertation focuses on the issue of node selfishness in cooperative transmission. It is common to assume in networks with a central authority, e.g. military networks, that nodes will always be willing to offer help to other nodes when requested to do so. This assumption may not be valid in ad hoc networks operating without a central authority. This section of the dissertation considers the effect selfish behavior on the energy efficiency of cooperative communication systems. Using tools from non-cooperative game theory, a two-player relaying game is formulated and analyzed in non-fading and fading channel scenarios. In non-fading channels, it is shown that a cooperative equilibrium can exist between two self-interested sources given that the end of the cooperative interaction is uncertain, that the sources can achieve mutual benefit through cooperation, and that the sources are sufficiently patient in the sense that they value future payoffs. In fading channels, a cooperative conditional trigger strategy is proposed and shown to be an equilibrium of the two-player game. Sources following this strategy are shown to achieve an energy efficiency very close to that of a centrally-controlled system when they are sufficiently patient. The results in this section show that cooperation can often be established between two purely self-interested sources without the development of extrinsic incentive mechanisms like virtual currency.

Online networks of individuals have been used to solve a number of problems in a scale that would not be possible if not within a connected, virtual and social environment such as the internet. However, the quality of solutions provided by individuals of an online network can vary significantly thus making work quality unreliable. This dissertation investigates factors that can influence the quality of the work output of individuals in online social networks. Specifically, we show that when solving tasks with small duration (under 5 minutes), also known as microtasks, individuals decision making will be strongly biased by costs of searching (and evaluating) options rather than financial or non-financial incentives. Indeed, we are able to show that we can influence individuals decisions, when solving problems, by rearranging elements visually to modify an the search sequence of an individual, be it by designing the virtual work environment or manipulating which options are first shown in non-controlled environments such as the Amazon Mechanical Turk labor market. We performed several experiments in online networks where individuals are invited to work on tasks with varying degrees of difficulty within three settings: mathematical games with objective truth (Sudoku and SAT instances), surveys with subjective evaluation (public policy polling) and labor markets (Amazon Mechanical Turk). We show that the time spent solving problems and the user interface are more relevant to the quality of work output than previous research have assumed and that individuals do not change this behavior while solving the sets of problems. Finally, to complement our study of online problem-solving, we present additional experiments in an online labor market (Amazon Mechanical Turk) that agrees with our networked experiments, shedding new light on how and why people solve problems.

A Teoria dos Jogos é amplamente utilizada no estudo de fenômenos de interação estratégica, em especial na análise de mercados de commodities. Esse trabalho faz uma análise preliminar do mercado brasileiro de eteno e propeno sob a ótica de um modelo baseado na Teoria dos Jogos, representado matematicamente através de um problema de complementaridade mista. Neste modelo, as empresas atuam em uma competição de Cournot e os custos de produção são parâmetros incertos, representados através de cenários, sendo que, no equilíbrio, três decisões devem ser tomadas: i) o portifólio de tecnologias para produção, ii) a capacidade de produção de cada tecnologia e iii) o nível de produção de cada tecnologia em cada cenário. Considerando as diversas limitações do estudo, as simulações realizadas com o modelo proposto mostram que o comportamento dos agentes da indústria petroquímica brasileira está mais próximo de tomadores de preços, sem possibilidade de regulação de preços através das quantidades produzidas. / Game Theory is widely used in the study of strategic interaction, especially in the analysis of commodity markets. This work makes a preliminary analysis of the Brazilian ethylene and propylene market from the perspective of a model based on game theory, represented mathematically by a mixed complementarity problem. In this model, firms behave as Cournot players and production costs are uncertain parameters, represented by scenarios, and in equilibrium three decisions must be made: i) the portfolio of technologies for production, ii) technologies capacity and iii) the level of production for each technology in each scenario. Considering the limitations of the study, the simulations carried out with the proposed model show that the behavior of the Brazilian petrochemical industry agents is closer to price takers, without possibility of price regulation by the quantities produced.

L’onde acoustique est utilisée par de nombreux systèmes et organismes marins pour communiquer, naviguer ou inférer de l’information sur l’environnement. Le développement des activités humaines liées au monde de la mer induit une augmentation du nombre de sources acoustiques en activité simultanée dans l’océan. L’environnement acoustique sous-marin (ASM) est donc partagé par de nombreuses sources hétérogènes (sonars, modems, mammifères marins, ...) entrant involontairement en compétition pour l’utilisation d’une ressource offerte par le canal de transmission. L’objectif de ce travail de thèse est de proposer des solutions permettant aux systèmes de communications ASM d’adapter leurs paramètres de transmission de manière intelligente, autonome et décentralisée selon l’environnement acoustique dans lequel ils évoluent. A plusieurs égards, les problématiques de ce sujet de thèse sont proches de celles ayant motivé le développement des recherches sur la radio cognitive. Cependant, les spécificités du milieu acoustique, les sources d’interférencesde diverses natures, et l’absence de standards de communications posent de nouvelles difficultés. / Underwater acoustic waves are used by many systems and biologic organisms to communicate, navigate or infer information about the environment. Future developments of human maritime activities imply an increase of the number of active acoustic sources in the oceans. The underwater environment is therefore shared by many heterogeneous sources (sonars, modems, marine mammals, ...) competing involuntarily for using the physical resources offered by the communication channel.The goal of this thesis is to provide solutions allowing autonomous and decentralized adaptation of the transmission strategies of underwater acoustic communication systems, according to the environment. To some extent, this work deals with topics that are closely related to what has motivated the first researches on cognitive radio systems. However, the specific properties of the underwater environment, the heterogeneity of interfering acoustic sources, and the absence of communication standards rise new difficulties.