[Show abstract][Hide abstract] ABSTRACT: In this paper, we address the problem of how to extend a ranking over single objects to another ranking over all possible collections of objects, taking into account the fact that objects grouped together can have mutual interaction. An answer to this issue is provided by using game theory and, specifically, the fact that an extension (i.e., a total proorder on the set of all subsets of objects) must be aligned with some probabilistic value, in the sense that the ranking of the objects (according to some probabilistic value computed on a numerical representation of the extension) must also preserve the primitive preorder on the singletons, no matter which utility function is used to represent the extension. We characterize families of aligned extensions, we focus on their geometric properties and we provide algorithms to verify their alignments. We also show that the framework introduced in this paper may be used to study a new class of extension problems, which integrate some features dealing with risk and complete uncertainty within the class of preference extension problems known in the literature with the name of sets as final outcomes.
Top 07/2015; 23(2). DOI:10.1007/s11750-014-0357-5 · 0.83 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The special issue on ICT-based strategies for environmental conflicts - to be published in the journal Strategic Behavior and the Environment - contains four peer-reviewed articles devoted to the analysis of multi-agents decision problems arising from the exploitation of environmental resources, and where Information and Communications Technologies are crucial for the design and the implementation of environmental policies. In this short presentation of the special issue, the Guest Editors provide a brief summary of the contributed papers, together with some insights gained from their original motivations and main results.
[Show abstract][Hide abstract] ABSTRACT: This introduction presents the theme of this volume, the rationale for it, and the history of the conference series from which it originated. It provides also a short description of the papers included.
International Game Theory Review 12/2012; 14(4). DOI:10.1142/S0219198912400014
[Show abstract][Hide abstract] ABSTRACT: The aim of this study is to identify and characterize the parts of an extensive form game that are “relevant” to determining whether the outcome of a certain strategy profile is an equilibrium outcome. We formally define what we mean by “relevant” and refer to the associated collection of information sets as essential. We apply this idea to a number of classic equilibrium concepts and discuss some implications of our approach.
International Journal of Games Theory 08/2012; 41(3). DOI:10.1007/s00182-011-0301-y · 0.58 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inter-Autonomous System (AS) links represent nowadays the real bottleneck of the Internet. Internet carriers may coordinate
to efficiently balance the load, but the current practice is often based on an uncoordinated selfish routing. Firstly, we
assess this issue by characterizing BGP route deviations across top-tier interconnections we could detect using recent Internet
routing history data. Then, in order to improve the current practice, we present a novel game-theoretical framework to efficiently
coordinate the routing on inter-AS links while modeling the non-cooperative carrier behavior. It relies on a coordinated use
of the Multi-Exit Discriminator (MED) attribute of BGP, hence it is nicknamed ClubMED (Coordinated MED). We define the routing
policy that shall be implemented upon Nash equilibria and Pareto-efficient profiles. We emulated the interconnection between
the Internet2 and the Geant2 networks, comparing our proposition to the current BGP practice. The results show that the route
stability can significantly be reinforced, the global routing cost can be significantly reduced, and the inter-AS link congestion
can be avoided.
Telecommunication Systems 10/2011; 48(1-2):77-92. DOI:10.1007/s11235-010-9335-x · 0.71 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this paper we propose an infrastructure access tariff in a cost allocation problem arising from the reorganization of the
railway sector in Europe. To that aim we introduce the class of infrastructure cost games. A game in this class is a sum of
airport games and what we call maintenance cost games, and models the infrastructure costs (building and maintenance) produced
when a set of different types of trains belonging to several agents makes use of a certain infrastructure. We study some properties
of infrastructure cost games and provide a formula for the Shapley value of a game in this class. The access tariff we propose
is based on the Shapley value of infrastructure cost games.
[Show abstract][Hide abstract] ABSTRACT: It is generally admitted that interdomain peering links represent nowadays the main bottleneck of the Internet, particularly because of lack of coordination between providers, which use independent and “selfish” routing policies. We are interested in identifying possible “light” coordination strategies that would allow carriers to better control their peering links while preserving their independence and respective interests. We propose a robust multipath routing coordination framework for peering carriers, which relies on the multiple-exit discriminator (MED) attribute of Border Gateway Protocol (BGP) as signaling medium. Our scheme relies on a game theory modeling, with a non-cooperative potential game considering both routing and congestions costs. Peering equilibrium multipath (PEMP) coordination policies can be implemented by selecting Pareto-superior Nash equilibria at each carrier. We compare different PEMP policies to BGP Multipath schemes by emulating a realistic peering scenario. Our results show that the routing cost can be decreased by roughly 10% with PEMP. We also show that the stability of routes can be significantly improved and that congestion can be practically avoided on the peering links. Finally, we discuss practical implementation aspects and extend the model to multiple players highlighting the possible incentives for the resulting extended peering framework.
[Show abstract][Hide abstract] ABSTRACT: MOTIVATION: The interpretation of gene interaction in biological networks generates the need for a meaningful ranking of network elements. Classical centrality analysis ranks network elements according to their importance but may fail to reflect the power of each gene in interaction with the others. RESULTS: We introduce a new approach using coalitional games to evaluate the centrality of genes in networks keeping into account genes' interactions. The Shapley value for coalitional games is used to express the power of each gene in interaction with the others and to stress the centrality of certain hub genes in the regulation of biological pathways of interest. The main improvement of this contribution, with respect to previous applications of game theory to gene expression analysis, consists in a finer resolution of the gene interaction investigated in the model, which is based on pairwise relationships of genes in the network. In addition, the new approach allows for the integration of a priori knowledge about genes playing a key function on a certain biological process. An approximation method for practical computation on large biological networks, together with a comparison with other centrality measures, is also presented.
[Show abstract][Hide abstract] ABSTRACT: We provide a characterization of the Banzhaf value on the class of the microarray games, and another characterization of the Shapley value, on the same class, in the spirit of [Moretti S, Patrone F, Bonassi S. The class of microarray games and the relevance index for genes. TOP 2007;15:256–80]. Then we compare the results given by the two indices when applied to a colon tumor data-set published in literature.
[Show abstract][Hide abstract] ABSTRACT: It is generally admitted that Inter-domain peering links represent nowadays the main bottleneck of the Internet, particularly because of lack of coordination between providers, which use independent and "selfish" routing policies. We are interested in identifying possible "light" coordination strategies, that would allow carriers to better control their peering links, while preserving their independence and respective interests. We propose a robust multi-path routing coordination framework for peering carriers, which relies on the MED attribute of BGP as signalling medium. Our scheme relies on a game theoretic modelling, with a non-cooperative potential game considering both routing and congestions costs. Peering Equilibrium MultiPath (PEMP) coordination policies can be implemented by selecting Pareto-superior Nash equilibria at each carrier. We compare different PEMP policies to BGP Multipath schemes by emulating a realistic peering scenario. Our results show that the routing cost can be decreased by roughly 10% with PEMP. We also show that the stability of routes can be significantly improved and that congestion can be practically avoided on the peering links.
Global Telecommunications Conference, 2009. GLOBECOM 2009. IEEE; 01/2010
[Show abstract][Hide abstract] ABSTRACT: The problem of kidney exchanges shares common features with the classical problem of exchange of indivisible goods studied in the mechanism design literature, while presenting additional constraints on the size of feasible exchanges. The solution of a kidney exchange problem can be summarized in a mapping from the relevant underlying characteristics of the players (patients and their donors) to the set of matchings. The goal is to select only matchings maximizing a chosen welfare function. Since the final outcome heavily depends on the private information in possess of the players, a basic requirement in order to reach efficiency is the truthful revelation of this information. We show that for the kidney exchange problem, a class of (in principle) efficient mechanisms does not enjoy the incentive compatibility property and therefore is subject to possible manipulations made by the players in order to profit of the misrepresentation of their private information.
Health Care Management Science 12/2009; 12(4):351-62. DOI:10.1007/s10729-008-9089-0 · 1.05 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Inter-domain peering links represent nowadays the real bottleneck of the Internet. On peering links carriers may coordinate to efficiently balance the load, but the current practice is often based on an uncoordinated selfish routing supported by the peer relationship. We present a novel game theoretical routing framework to efficiently coordinate the routing on peering links while modelling the non-cooperative carrier behaviour. It relies on a collaborative use of the multi-exit discriminator (MED) attribute of BGP, hence it is nicknamed ClubMED (coordinated MED). The incentives are the minimization of carrier routing costs, the control of peering link congestions and peering route stability. For the ClubMED game, we define the Nash equilibrium multi-path (NEMP) routing policy that shall be implemented upon Nash equilibria and Pareto-efficient profiles. Intra-domain interior gateway protocol (IGP) weight optimizations are consistently integrated into the framework. We emulated the peering settlement between the Internet2 and the Geant2 networks, employing real datasets, comparing the ClubMED results to the current BGP practice. The results show that the global routing cost can be reduced of roughly 17%, that the peering link congestion can be avoided and that the stability of the routes can significantly be reinforced.
Next Generation Internet Networks, 2009. NGI '09; 08/2009
[Show abstract][Hide abstract] ABSTRACT: Corruption in the public sector erodes tax compliance and leads to higher tax evasion. Moreover, corrupt public officials abuse their public power to extort bribes from the private agents. In both types of interaction with the public sector, the private agents are bound to face uncertainty with respect to their disposable incomes. To analyse effects of this uncertainty, a stochastic dynamic growth model with the public sector is examined. It is shown that deterministic excessive red tape and corruption deteriorate the growth potential through income redistribution and public sector inefficiencies. Most importantly, it is demonstrated that the increase in corruption via higher uncertainty exerts adverse effects on capital accumulation, thus leading to lower growth rates.
[Show abstract][Hide abstract] ABSTRACT: In this ”tutorial” it is offered a quick introduction to game theory and to some suggested readings on the subject. It is
also considered a small set of game theoretical applications in the bioinformatics field.
Computational Intelligence Methods for Bioinformatics and Biostatistics, 6th International Meeting, CIBB 2009, Genoa, Italy, October 15-17, 2009, Revised Selected Papers; 01/2009
[Show abstract][Hide abstract] ABSTRACT: Background
In gene expression analysis, statistical tests for differential gene expression provide lists of candidate genes having, individually, a sufficiently low p-value. However, the interpretation of each single p-value within complex systems involving several interacting genes is problematic. In parallel, in the last sixty years, game theory has been applied to political and social problems to assess the power of interacting agents in forcing a decision and, more recently, to represent the relevance of genes in response to certain conditions.
In this paper we introduce a Bootstrap procedure to test the null hypothesis that each gene has the same relevance between two conditions, where the relevance is represented by the Shapley value of a particular coalitional game defined on a microarray data-set. This method, which is called Comparative Analysis of Shapley value (shortly, CASh), is applied to data concerning the gene expression in children differentially exposed to air pollution. The results provided by CASh are compared with the results from a parametric statistical test for testing differential gene expression. Both lists of genes provided by CASh and t-test are informative enough to discriminate exposed subjects on the basis of their gene expression profiles. While many genes are selected in common by CASh and the parametric test, it turns out that the biological interpretation of the differences between these two selections is more interesting, suggesting a different interpretation of the main biological pathways in gene expression regulation for exposed individuals. A simulation study suggests that CASh offers more power than t-test for the detection of differential gene expression variability.
CASh is successfully applied to gene expression analysis of a data-set where the joint expression behavior of genes may be critical to characterize the expression response to air pollution. We demonstrate a synergistic effect between coalitional games and statistics that resulted in a selection of genes with a potential impact in the regulation of complex pathways.
[Show abstract][Hide abstract] ABSTRACT: This paper presents selected contributions from the 6th Meeting on Game Theory and Practice Dedicated to Development, Natural Resources and the Environment that was held in Zaragoza (Spain) from 10 to 12 of July 2006. The dramatic increase in the application and use of game theory models for policy making in natural resources and the environment justifies the attention that is devoted to such topics. We provide examples for such applications, underlying the role they played. The contributions of the papers in this special section and the links between them are presented, together with a short synthesis of the range of contributions that are worth mentioning and would support policy making in fishery, water, and environmental regulation.
International Game Theory Review 09/2008; 10(03):221-228. DOI:10.1142/S021919890800190X