Mechanism design for distributed task and resource allocation among self-interested agents in virtual organizations

The aggregate power of all resources on the Internet is enormous. The Internet can be viewed as a massive virtual organization that holds tremendous amounts of information and resources with different ownerships. However, little is known about how to run this organization efficiently. This dissertation studies the problems of distributed task and resource allocation among self-interested agents in virtual organizations. The developed solutions are not allocation mechanisms that can be imposed by a centralized designer, but decentralized interaction mechanisms that provide incentives to self-interested agents to behave cooperatively. These mechanisms also take computational tractability into consideration due to the inherent complexity of distributed task and resource allocation problems. Targeted allocation mechanisms can achieve global task allocation efficiency in a virtual organization and establish stable resource-sharing communities based on agentsâÃÂàown decisions about whether or not to behave cooperatively. This high level goal requires solving the following problems: synthetic task allocation, decentralized coalition formation and automated multiparty negotiation. For synthetic task allocation, in which each task needs to be accomplished by a virtual team composed of self-interested agents from different real organizations, my approach is to formalize the synthetic task allocation problem as an algorithmic mechanism design optimization problem. I have developed two approximation mechanisms that I prove are incentive compatible for a synthetic task allocation problem. This dissertation also develops a decentralized coalition formation mechanism, which is based on explicit negotiation among self-interested agents. Each agent makes its own decisions about whether or not to join a candidate coalition. The resulting coalitions are stable in the core in terms of coalition rationality. I have applied this mechanism to form resource sharing coalitions in computational grids and buyer coalitions in electronic markets. The developed negotiation mechanism in the decentralized coalition formation mechanism realizes automated multilateral negotiation among self-interested agents who have symmetric authority (i.e., no mediator exists and agents are peers). In combination, the decentralized allocation mechanisms presented in this dissertation lay a foundation for realizing automated resource management in open and scalable virtual organizations

A Controlled Matching Game for WLANs

International audienceIn multi-rate IEEE 802.11 WLANs, the traditional user association based on the strongest received signal and the well known anomaly of the MAC protocol can lead to overloaded Access Points (APs), and poor or heterogeneous performance. Our goal is to propose an alternative game-theoretic approach for association. We model the joint resource allocation and user association as a matching game with complementarities and peer effects consisting of selfish players solely interested in their individual throughputs. Using recent game-theoretic results we first show that various resource sharing protocols actually fall in the scope of the set of stability-inducing resource allocation schemes. The game makes an extensive use of the Nash bargaining and some of its related properties that allow to control the incentives of the players. We show that the proposed mechanism can greatly improve the efficiency of 802.11 with heterogeneous nodes and reduce the negative impact of peer effects such as its MAC anomaly. The mechanism can be implemented as a virtual connectivity management layer to achieve efficient APs-user associations without modification of the MAC layer

International Education as Policy: A Discourse Coalition Framework Analysis of the Construction, Context, and Empowerment of Ontarios International Education Storylines

This study aims to examine the international education (IE) policy-making context in Ontario for the period from 2005 to mid-2017 while also taking into account the announcement of the new policy document Ontarios International Postsecondary Education Strategy 2018. It sets out to answer three research questions: (a) How is international education constructed as a policy discourse in the postsecondary sector in Ontario? (b) Who are the policy actors who are contributing to the postsecondary international education policy-making process in Ontario? and (c) What role do they play in influencing IE policy and empowering and silencing different discourses? To answer these research questions, this study adopts Maarten Hajers Discourse Coalition Framework (DCF) and steps of doing argumentative discursive analysis (2006). Data sources included IE stories in the three highest-circulation newspapers in Ontario (415 articles); 23 interviews with policy actors, and 195 policy documents. Whereas policy studies employing DCF have typically identified oppositional storylines, the findings of this study reveal one dominant storyline: Internationalize. All discourses agree, to varying degrees, that IE is desirable and beneficial to the postsecondary education sector and Ontario. However, within the overarching Internationalize storyline, three storylines emerge: (a) Internationalize, it is good for the economy (Economy); (b) Internationalize, yet manage its risks (Risks); (c) Internationalize, it is Canadas gateway to the world (Gateway). The Economy storyline achieves hegemony as it succeeds in imposing its logic and ways of deliberation on the IE policy landscape (structuration) and is translated into institutional practices and policies (institutionalization). The study also reveals a shifting terrain in the IE policy landscape with the emergence of a new Regulate IE storyline, which has succeeded in introducing regulation and accountability discourses and reframing the hegemonic Economy storyline. By moving away from the state and focusing on storylines, this study reveals the fragmentation of the IE policy landscape and exposes actors from diverse scales, levels, disciplines, and contexts; all of whom contribute to the construction of IE and its related policies. One of the main findings of this study is the role of the media in building the IE narrative and mobilizing storylines. This research contributes to our understanding of the economic aspect of internationalization, which goes beyond discourses of neo-liberalism, and argues against the traditional binary categorizations of socio-cultural and educational versus economic internationalization. On a theoretical level, the study outlines the strengths of DCF and unsettles its conceptualization of collective and individual discursive agencies

COIN@AAMAS2015

COIN@AAMAS2015 is the nineteenth edition of the series and the fourteen papers included in these proceedings demonstrate the vitality of the community and will provide the grounds for a solid workshop program and what we expect will be a most enjoyable and enriching debate.Peer reviewe

Spectrum Sensing and Multiple Access Schemes for Cognitive Radio Networks

Increasing demands on the radio spectrum have driven wireless engineers to rethink approaches by which devices should access this natural, and arguably scarce, re- source. Cognitive Radio (CR) has arisen as a new wireless communication paradigm aimed at solving the spectrum underutilization problem. In this thesis, we explore a novel variety of techniques aimed at spectrum sensing which serves as a fundamental mechanism to find unused portions of the electromagnetic spectrum. We present several spectrum sensing methods based on multiple antennas and evaluate their receiving operating characteristics. We study a cyclostationary feature detection technique by means of multiple cyclic frequencies. We make use of a spec- trum sensing method called sequential analysis that allows us to significantly decrease the time needed for detecting the presence of a licensed user. We extend this scheme allowing each CR user to perform the sequential analysis algorithm and send their local decision to a fusion centre. This enables for an average faster and more accurate detection. We present an original technique for accounting for spatial and temporal cor- relation influence in spectrum sensing. This reflects on the impact of the scattering environment on detection methods using multiple antennas. The approach is based on the scattering geometry and resulting correlation properties of the received signal at each CR device. Finally, the problem of spectrum sharing for CR networks is addressed in or- der to take advantage of the detected unused frequency bands. We proposed a new multiple access scheme based on the Game Theory. We examine the scenario where a random number of CR users (considered as players) compete to access the radio spec- trum. We calculate the optimal probability of transmission which maximizes the CR throughput along with the minimum harm caused to the licensed users’ performance

Flexible Kooperation zwischen Autonomen Agenten in Dynamischen Umgebungen

Die vorliegende Dissertation präsentiert ein Schema zur Holonenformierung in dynamischen Umgebungen eines holonischen Multiagenten-Systems. Holo- ne werden dazu eingesetzt, um eine Gruppe von Agenten für einen begrenzten Zeitraum zu einem strukturierten Verbund zusammenzufassen. Unter der Führung eines ausgezeichneten Agenten, dem Holonenführer bzw. Kopf des Holons, können gemeinsam komplexe Aufgaben gelöst werden. Die Holonenführer, wie auch die restlichen Agenten eines Multiagenten-Systems, besitzen dabei nur ein eingeschränktes, vages und zum Teil fehlerhaftes Wissen über die anderen Agenten. Das Schema beschreibt, wie jeder Agent sein Wissen erlernen und davon ausgehend potentielle Holonenstrukturen simulationsbasiert aufbauen kann. Anschlieÿend werden diese hypothetischen Holonenstrukturen in Verhandlungen realisiert. Zur Umsetzung des Schemas und der daraus resultierenden Algorithmen wird ein mathematischer Formalismus zur Abbildung eines Multiagenten- Systems auf einen Vektorraum vorgestellt, der es ermöglicht, die Entitäten des Multiagenten-Systems und die Funktionen des Schemas formal zu beschreiben. Aufbauend auf diesen Arbeiten und des Schemas werden abschlieÿend vier Algorithmen, von einem einfachen randomisierten Verfahren bis hin zu komplexen wissensbasierten Verfahren zur Holonenformierung, exemplarisch entwickelt, diskutiert und evaluiert.This work proposes a scheme for the formation of holonic agents in a multiagentsystem acting in a dynamic environment. This model captures cooperative holonic multiagent-systems in which each agent has incomplete, vague and erroneous information about the other agents and about its dynamic and uncertain world. Holons are temporarily formed to fulfill complex tasks, that a single agent cannot handle alone. To find assistance the head of a holon continuously tries to improve its holonic structure. Therefore it builds a set of hypothetical holons, rating them and if a higher ranked holon structure than the current one is found, it starts with the (re-)negotiation of the holon. Also if the holon is for some reason not longer capable to achieve its goals, re-negotiation starts. The scheme describes in particular, how an agent learns the properties of other agents. Based on this knowledge the agents are then able to build hypothetical holons by simulations. In the following these hypothetical holons are realised by bilateral negotiations with the agents of that pre-computed holonstructure. For describing this scheme and the algorithms based on this scheme, I first present a formalism to map a multiagent-system onto a vector space, such that it is possible to give a formal description of the entities of a multiagenten-system and of the functions of the proposed scheme. Finally present four algorithms to form dynamically holons based on that scheme. These algorithms consist of a simple randomised agent selection to a complex knowledge-based selection of relevant agents to solve the given tasks. These algorithms are in the end discussed and evaluated in detail