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http://hdl.handle.net/2117/3429
Sat, 30 May 2015 00:47:14 GMT2015-05-30T00:47:14Zwebmaster.bupc@upc.eduUniversitat Politècnica de Catalunya. Servei de Biblioteques i DocumentaciónoThe proportional partitional Shapley value
http://hdl.handle.net/2117/27972
Title: The proportional partitional Shapley value
Authors: Alonso Meijide, José María; Carreras Escobar, Francisco; Costa Bouzas, Julián; García Jurado, Ignacio
Abstract: A new coalitional value is proposed under the hypothesis of isolated unions. The main
difference between this value and the Aumann–Drèze value is that the allocations within
each union are not given by the Shapley value of the restricted game but proportionally
to the Shapley value of the original game. Axiomatic characterizations of the new value,
examples illustrating its application and a comparative discussion are provided.Tue, 19 May 2015 17:50:13 GMThttp://hdl.handle.net/2117/279722015-05-19T17:50:13ZAlonso Meijide, José María; Carreras Escobar, Francisco; Costa Bouzas, Julián; García Jurado, IgnacionoGame theory, (TU) cooperative game, Shapley value, Coalition structure, Aumann–Drèze valueA new coalitional value is proposed under the hypothesis of isolated unions. The main
difference between this value and the Aumann–Drèze value is that the allocations within
each union are not given by the Shapley value of the restricted game but proportionally
to the Shapley value of the original game. Axiomatic characterizations of the new value,
examples illustrating its application and a comparative discussion are provided.Coalitional multinomial probabilistic values
http://hdl.handle.net/2117/27632
Title: Coalitional multinomial probabilistic values
Authors: Carreras Escobar, Francisco; Puente del Campo, María Albina
Abstract: We introduce a new family of coalitional values designed to take into account players’ attitudes with regard to cooperation. This new family of values applies to cooperative games with a coalition structure by combining the Shapley value and the multinomial probabilistic values, thus generalizing the symmetric coalitional binomial semivalues. Besides an axiomatic characterization, a computational procedure is provided in terms of the multilinear extension of the game and an application to the Catalonia Parliament, Legislature 2003–2007, is shown.Tue, 28 Apr 2015 17:30:59 GMThttp://hdl.handle.net/2117/276322015-04-28T17:30:59ZCarreras Escobar, Francisco; Puente del Campo, María AlbinanoCooperative game, Shapley value, Multinomial probabilistic value, Coalition structure, Multilinear extensionWe introduce a new family of coalitional values designed to take into account players’ attitudes with regard to cooperation. This new family of values applies to cooperative games with a coalition structure by combining the Shapley value and the multinomial probabilistic values, thus generalizing the symmetric coalitional binomial semivalues. Besides an axiomatic characterization, a computational procedure is provided in terms of the multilinear extension of the game and an application to the Catalonia Parliament, Legislature 2003–2007, is shown.An axiomatic characterization of the potential decisiveness index
http://hdl.handle.net/2117/27526
Title: An axiomatic characterization of the potential decisiveness index
Authors: Freixas Bosch, Josep; Pons Navarro, Montserrat
Abstract: Let us consider that somebody is extremely interested in increasing the probability of a proposal to be approved by a certain committee and that to achieve this goal he/she is prepared to pay off one member of the committee. In a situation like this one, and assuming that vote-buying is allowed and free of stigma, which voter should be offered a bribe? The potential decisiveness index for simple games, which measures the effect that ensuring one positive vote produces for the probability of passing the issue at hand, is a good tool with which to acquire the answer. An axiomatic characterization of this index is given in this paper, and its relation to other classical power indices is shown.http://hdl.handle.net/2117/27526Freixas Bosch, Josep; Pons Navarro, MontserratnoGame theory, Potential decisiveness index, Measure for bribes, Axiomatization, Standard power indices, Relationship among several measures, Ordinal equivalence, Voting games, Power, Sucess, Voters, Values, LuckyLet us consider that somebody is extremely interested in increasing the probability of a proposal to be approved by a certain committee and that to achieve this goal he/she is prepared to pay off one member of the committee. In a situation like this one, and assuming that vote-buying is allowed and free of stigma, which voter should be offered a bribe? The potential decisiveness index for simple games, which measures the effect that ensuring one positive vote produces for the probability of passing the issue at hand, is a good tool with which to acquire the answer. An axiomatic characterization of this index is given in this paper, and its relation to other classical power indices is shown.On the complexity of exchanging
http://hdl.handle.net/2117/27400
Title: On the complexity of exchanging
Authors: Molinero Albareda, Xavier; Olsen, Martin; Serna Iglesias, María José
Abstract: We analyze the computational complexity of the problem of deciding
whether, for a given simple game, there exists the possibility of rearranging the participants in a set of j given losing coalitions into a set of j winning coalitions. We also look at the problem of turning winning coalitions into losing coalitions. We analyze the problem when the simple game is represented by a list of wining, losing, minimal winning or maximal loosing coalitions.Thu, 16 Apr 2015 17:13:57 GMThttp://hdl.handle.net/2117/274002015-04-16T17:13:57ZMolinero Albareda, Xavier; Olsen, Martin; Serna Iglesias, María JosénoTradeness of Simple Games, Computational ComplexityWe analyze the computational complexity of the problem of deciding
whether, for a given simple game, there exists the possibility of rearranging the participants in a set of j given losing coalitions into a set of j winning coalitions. We also look at the problem of turning winning coalitions into losing coalitions. We analyze the problem when the simple game is represented by a list of wining, losing, minimal winning or maximal loosing coalitions.Cooperation through social influence
http://hdl.handle.net/2117/26600
Title: Cooperation through social influence
Authors: Molinero Albareda, Xavier; Riquelme Csori, Fabián; Serna Iglesias, María José
Abstract: We consider a simple and altruistic multiagent system in which the agents are eager to perform a collective task but where their real engagement depends on the willingness to perform the task of other influential agents. We model this scenario by an influence game, a cooperative simple game in which a team (or coalition) of players succeeds if it is able to convince enough agents to participate in the task (to vote in favor of a decision). We take the linear threshold model as the influence model. We show first the expressiveness of influence games showing that they capture the class of simple games. Then we characterize the computational complexity of various problems on influence games, including measures (length and width), values (Shapley-Shubik and Banzhaf) and properties (of teams and players). Finally, we analyze those problems for some particular extremal cases, with respect to the propagation of influence, showing tighter complexity characterizations.Thu, 05 Mar 2015 17:47:09 GMThttp://hdl.handle.net/2117/266002015-03-05T17:47:09ZMolinero Albareda, Xavier; Riquelme Csori, Fabián; Serna Iglesias, María JosénoComputational complexity, Influence games, Simple games, Spread of influenceWe consider a simple and altruistic multiagent system in which the agents are eager to perform a collective task but where their real engagement depends on the willingness to perform the task of other influential agents. We model this scenario by an influence game, a cooperative simple game in which a team (or coalition) of players succeeds if it is able to convince enough agents to participate in the task (to vote in favor of a decision). We take the linear threshold model as the influence model. We show first the expressiveness of influence games showing that they capture the class of simple games. Then we characterize the computational complexity of various problems on influence games, including measures (length and width), values (Shapley-Shubik and Banzhaf) and properties (of teams and players). Finally, we analyze those problems for some particular extremal cases, with respect to the propagation of influence, showing tighter complexity characterizations.On the complexity of problems on simple games
http://hdl.handle.net/2117/25093
Title: On the complexity of problems on simple games
Authors: Freixas Bosch, Josep; Molinero Albareda, Xavier; Olsen, Martin; Serna Iglesias, María José
Abstract: Simple games cover voting systems in which a single alter-
native, such as a bill or an amendment, is pitted against the status quo. A simple game or a yes-no voting system is a set of rules that specifies exactly which collections of “yea” votes yield passage of the issue at hand. Each of these collections of “yea” voters forms a winning coalition. We are interested in performing a complexity analysis on problems defined on such families of games. This analysis as usual depends on the game representation used as input. We consider four natural explicit representations: winning, losing, minimal winning, and maximal losing. We first analyze the complexity of testing whether a game is simple and testing whether a game is weighted. We show that, for the four types of representations, both problems can be solved in polynomial time. Finally, we provide results on the complexity of testing whether a simple game or a weighted game is of a special type. We analyze strongness, properness, weightedness, homogeneousness, decisiveness and majorityness, which are desirable properties to be fulfilled for a simple game.
Finally, we consider the possibility of representing a game in a more
succinct and natural way and show that the corresponding recognition
problem is hard.Thu, 18 Dec 2014 19:12:37 GMThttp://hdl.handle.net/2117/250932014-12-18T19:12:37ZFreixas Bosch, Josep; Molinero Albareda, Xavier; Olsen, Martin; Serna Iglesias, María JosénoSimple, Weighted, Majority games, NP-completenessSimple games cover voting systems in which a single alter-
native, such as a bill or an amendment, is pitted against the status quo. A simple game or a yes-no voting system is a set of rules that specifies exactly which collections of “yea” votes yield passage of the issue at hand. Each of these collections of “yea” voters forms a winning coalition. We are interested in performing a complexity analysis on problems defined on such families of games. This analysis as usual depends on the game representation used as input. We consider four natural explicit representations: winning, losing, minimal winning, and maximal losing. We first analyze the complexity of testing whether a game is simple and testing whether a game is weighted. We show that, for the four types of representations, both problems can be solved in polynomial time. Finally, we provide results on the complexity of testing whether a simple game or a weighted game is of a special type. We analyze strongness, properness, weightedness, homogeneousness, decisiveness and majorityness, which are desirable properties to be fulfilled for a simple game.
Finally, we consider the possibility of representing a game in a more
succinct and natural way and show that the corresponding recognition
problem is hard.Enumeration of weighted games with minimum and an analysis of voting power for bipartite complete games with minimum
http://hdl.handle.net/2117/25089
Title: Enumeration of weighted games with minimum and an analysis of voting power for bipartite complete games with minimum
Authors: Freixas Bosch, Josep; Kurz, Sascha
Abstract: This paper is a twofold contribution. First, it contributes to the problem of enumerating some classes of simple games and in particular provides the number of weighted games with minimum and the number of weighted games for the dual class as well. Second, we focus on the special case of bipartite complete games with minimum, and we compare and rank these games according to the behavior of some efficient power indices of players of type 1 (or of type 2). The main result of this second part establishes all allowable rankings of these games when the Shapley-Shubik power index is used on players of type 1.Thu, 18 Dec 2014 17:52:05 GMThttp://hdl.handle.net/2117/250892014-12-18T17:52:05ZFreixas Bosch, Josep; Kurz, SaschanoSimple game, Weighted and complete games, Enumerations, Shapley-Shubik power index, Banzhaf power indices, Ordinal equivalence, Europena Union, Dimension, Semivalues, Council, Indexes, SystemThis paper is a twofold contribution. First, it contributes to the problem of enumerating some classes of simple games and in particular provides the number of weighted games with minimum and the number of weighted games for the dual class as well. Second, we focus on the special case of bipartite complete games with minimum, and we compare and rank these games according to the behavior of some efficient power indices of players of type 1 (or of type 2). The main result of this second part establishes all allowable rankings of these games when the Shapley-Shubik power index is used on players of type 1.On minimum integer representations of weighted games
http://hdl.handle.net/2117/24931
Title: On minimum integer representations of weighted games
Authors: Freixas Bosch, Josep; Kurz, Sascha
Abstract: We study minimum integer representations of weighted games, i.e. representations where the weights are integers and every other integer representation is at least as large in each component. Those minimum integer representations, if they exist at all, are linked with some solution concepts in game theory. Closing existing gaps in the literature, we prove that each weighted game with two types of voters admits a (unique) minimum integer representation, and give new examples for more than two types of voters without a minimum integer representation. We characterize the possible weights in minimum integer representations and give examples for t >= 4 types of voters without a minimum integer representation preserving types, i.e. where we additionally require that the weights are equal within equivalence classes of voters. (C) 2013 Elsevier B.V. All rights reserved.Thu, 04 Dec 2014 18:58:18 GMThttp://hdl.handle.net/2117/249312014-12-04T18:58:18ZFreixas Bosch, Josep; Kurz, SaschanoWeighted games, Minimum integer representations, Representations with minimum sumWe study minimum integer representations of weighted games, i.e. representations where the weights are integers and every other integer representation is at least as large in each component. Those minimum integer representations, if they exist at all, are linked with some solution concepts in game theory. Closing existing gaps in the literature, we prove that each weighted game with two types of voters admits a (unique) minimum integer representation, and give new examples for more than two types of voters without a minimum integer representation. We characterize the possible weights in minimum integer representations and give examples for t >= 4 types of voters without a minimum integer representation preserving types, i.e. where we additionally require that the weights are equal within equivalence classes of voters. (C) 2013 Elsevier B.V. All rights reserved.Achievable hierarchies in voting games with abstention
http://hdl.handle.net/2117/24930
Title: Achievable hierarchies in voting games with abstention
Authors: Freixas Bosch, Josep; Tchantcho, Bertrand; Tedjeugang, Narcisse
Abstract: It is well known that he influence relation orders the voters the same way as the classical Banzhaf and Shapley-Shubik indices do when they are extended to the voting games with abstention (VGA) in the class of complete games. Moreover, all hierarchies for the influence relation are achievable in the class of complete VGA. The aim of this paper is twofold. Firstly, we show that all hierarchies are achievable in a subclass of weighted VGA, the class of weighted games for which a single weight is assigned to voters. Secondly, we conduct a partial study of achievable hierarchies within the subclass of H-complete games, that is, complete games under stronger versions of influence relation. (C) 2013 Elsevier B.V. All rights reserved.Thu, 04 Dec 2014 18:40:45 GMThttp://hdl.handle.net/2117/249302014-12-04T18:40:45ZFreixas Bosch, Josep; Tchantcho, Bertrand; Tedjeugang, NarcissenoGame theory, (3, 2) Voting rules, Abstention, Decision support systems, Weightedness and completeness, Hierarchies, Ordinal equivalence, Power, Aapproval, Systems, Banzhaf, Output, InputIt is well known that he influence relation orders the voters the same way as the classical Banzhaf and Shapley-Shubik indices do when they are extended to the voting games with abstention (VGA) in the class of complete games. Moreover, all hierarchies for the influence relation are achievable in the class of complete VGA. The aim of this paper is twofold. Firstly, we show that all hierarchies are achievable in a subclass of weighted VGA, the class of weighted games for which a single weight is assigned to voters. Secondly, we conduct a partial study of achievable hierarchies within the subclass of H-complete games, that is, complete games under stronger versions of influence relation. (C) 2013 Elsevier B.V. All rights reserved.Voting games with abstention: linking completeness and weightedness
http://hdl.handle.net/2117/24929
Title: Voting games with abstention: linking completeness and weightedness
Authors: Freixas Bosch, Josep; Tchantcho, Bertrand; Tedjeugang, Narcisse
Abstract: Weighted games for several levels of approval in input and output were introduced in [9]. An extension of the desirability relation for simple games, called the influence relation, was introduced for games with several levels of approval in input in [24] (see also [18]). However, there are weighted games not being complete for the influence relation, something different to what occurs for simple games. In this paper we introduce several extensions of the desirability relation for simple games and from the completeness of them it follows the consistent link with weighted games, which solves the existing gap. Moreover, we prove that the influence relation is consistent with a known subclass of weighted games: strongly weighted games. (C) 2013 Elsevier B.V. All rights reserved.http://hdl.handle.net/2117/24929Freixas Bosch, Josep; Tchantcho, Bertrand; Tedjeugang, NarcissenoDecision making process, Voting systems in democratic organizations, Multiple levels of approval, Weightedness and completeness, Desirability relations, Approval, Power, Representation, Systems, Output, InputWeighted games for several levels of approval in input and output were introduced in [9]. An extension of the desirability relation for simple games, called the influence relation, was introduced for games with several levels of approval in input in [24] (see also [18]). However, there are weighted games not being complete for the influence relation, something different to what occurs for simple games. In this paper we introduce several extensions of the desirability relation for simple games and from the completeness of them it follows the consistent link with weighted games, which solves the existing gap. Moreover, we prove that the influence relation is consistent with a known subclass of weighted games: strongly weighted games. (C) 2013 Elsevier B.V. All rights reserved.Similarities and differences between success and decisiveness
http://hdl.handle.net/2117/24568
Title: Similarities and differences between success and decisiveness
Authors: Freixas Bosch, Josep; Pons Vallès, Montserrat
Abstract: We consider binary voting systems in which a probability distribution
over coalitions is known. In this broader context decisiveness is
an extension of the Penrose-Banzhaf index and success an extension of the Rae index for simple games. Although decisiveness and success are conceptually different we analyze their numerical behavior. The main result provides necessary and sufficient conditions for the ordinal equivalence of them. Indeed, under anonymous probability distributions they become ordinally equivalent. Moreover, it is proved that for these distributions, decisiveness and success respect the strength of the seats, whereas luckiness reverses the order.Wed, 05 Nov 2014 14:51:09 GMThttp://hdl.handle.net/2117/245682014-11-05T14:51:09ZFreixas Bosch, Josep; Pons Vallès, MontserratnoRankings, Success, Decisiveness, Single peaked preferencesWe consider binary voting systems in which a probability distribution
over coalitions is known. In this broader context decisiveness is
an extension of the Penrose-Banzhaf index and success an extension of the Rae index for simple games. Although decisiveness and success are conceptually different we analyze their numerical behavior. The main result provides necessary and sufficient conditions for the ordinal equivalence of them. Indeed, under anonymous probability distributions they become ordinally equivalent. Moreover, it is proved that for these distributions, decisiveness and success respect the strength of the seats, whereas luckiness reverses the order.Pasado, presente y futuro de la mentoría en la Escuela Politécnica Superior de Ingeniería de Manresa
http://hdl.handle.net/2117/24531
Title: Pasado, presente y futuro de la mentoría en la Escuela Politécnica Superior de Ingeniería de Manresa
Authors: Gorchs Altarriba, Roser; Molinero Albareda, Xavier; Garriga Sucarrats, Salvador
Abstract: This work details the coaching (mentoring) at Manresa School of Engineering (Escola Politècnica Superior d'Enginyeria de Manresa). It considers the evolution from the beginning (course 2009-10) to the present. Each course (2009-10, 2010-11 and 2011-12) is analized with some improve- ment actions. Finally, some proposes to the future are also introduced.Fri, 31 Oct 2014 15:08:30 GMThttp://hdl.handle.net/2117/245312014-10-31T15:08:30ZGorchs Altarriba, Roser; Molinero Albareda, Xavier; Garriga Sucarrats, SalvadornoCoaching, Nuevos Estudiantes en la UniversidadThis work details the coaching (mentoring) at Manresa School of Engineering (Escola Politècnica Superior d'Enginyeria de Manresa). It considers the evolution from the beginning (course 2009-10) to the present. Each course (2009-10, 2010-11 and 2011-12) is analized with some improve- ment actions. Finally, some proposes to the future are also introduced.Power indices of influence games and new centrality measures for agent societies and social networks
http://hdl.handle.net/2117/24245
Title: Power indices of influence games and new centrality measures for agent societies and social networks
Authors: Molinero Albareda, Xavier; Riquelme Csori, Fabián; Serna Iglesias, María José
Abstract: We propose as centrality measures for social networks two classical power indices, Banzhaf and Shapley-Shubik, and two new measures, effort and satisfaction, related to the spread of influence process that emerge from the subjacent influence game. We perform a comparison of these measures with three well known centrality measures, degree, closeness and betweenness, applied to three simple social networks.Fri, 03 Oct 2014 13:58:17 GMThttp://hdl.handle.net/2117/242452014-10-03T13:58:17ZMolinero Albareda, Xavier; Riquelme Csori, Fabián; Serna Iglesias, María JosénoSocial network, Centrality, Power index, Influence game, Simple gameWe propose as centrality measures for social networks two classical power indices, Banzhaf and Shapley-Shubik, and two new measures, effort and satisfaction, related to the spread of influence process that emerge from the subjacent influence game. We perform a comparison of these measures with three well known centrality measures, degree, closeness and betweenness, applied to three simple social networks.On a-roughly weighted games
http://hdl.handle.net/2117/24210
Title: On a-roughly weighted games
Authors: Freixas Bosch, Josep; Kurz, Sascha
Abstract: Gvozdeva, Hemaspaandra, and Slinko (2011) have introduced three hierarchies for simple games in order to measure the distance of a given simple game to the class of (roughly) weighted voting games. Their third class C-alpha consists of all simple games permitting a weighted representation such that each winning coalition has a weight of at least and each losing coalition a weight of at most alpha. For a given game the minimal possible value of alpha is called its critical threshold value. We continue the work on the critical threshold value, initiated by Gvozdeva et al., and contribute some new results on the possible values for a given number of voters as well as some general bounds for restricted subclasses of games. A strong relation between this concept and the cost of stability, i.e. the minimum amount of external payment to ensure stability in a coalitional game, is uncovered.Thu, 02 Oct 2014 16:20:55 GMThttp://hdl.handle.net/2117/242102014-10-02T16:20:55ZFreixas Bosch, Josep; Kurz, SaschanoSimple game, Weighted game, Complete simple game, Roughly weighted game, Voting theory, HierarchyGvozdeva, Hemaspaandra, and Slinko (2011) have introduced three hierarchies for simple games in order to measure the distance of a given simple game to the class of (roughly) weighted voting games. Their third class C-alpha consists of all simple games permitting a weighted representation such that each winning coalition has a weight of at least and each losing coalition a weight of at most alpha. For a given game the minimal possible value of alpha is called its critical threshold value. We continue the work on the critical threshold value, initiated by Gvozdeva et al., and contribute some new results on the possible values for a given number of voters as well as some general bounds for restricted subclasses of games. A strong relation between this concept and the cost of stability, i.e. the minimum amount of external payment to ensure stability in a coalitional game, is uncovered.The representativeness reliability importance measure
http://hdl.handle.net/2117/24048
Title: The representativeness reliability importance measure
Authors: Freixas Bosch, Josep; Pons Vallès, Montserrat
Abstract: A new reliability importance measure for
components in a system, that we call Representativeness
measure, is introduced. It evaluates to which extent the
performance of a component is representative of the
performance of the whole system. Its relationship with
Birnbaum’s measure is analyzed, and the ranking of
components given by both measures are compared. These
rankings happen to be equal when all components have the
same reliability but different in general. In contrast with
Birnbaum’s, the Representativeness reliability importance
measure of a component does depend on its reliability.Fri, 12 Sep 2014 10:45:20 GMThttp://hdl.handle.net/2117/240482014-09-12T10:45:20ZFreixas Bosch, Josep; Pons Vallès, MontserratnoReliability importance measures, Structural importance measures, Criticality relation, Coherent systems, node criticality relation, Birnbaum RIM, Birnbaum SIMA new reliability importance measure for
components in a system, that we call Representativeness
measure, is introduced. It evaluates to which extent the
performance of a component is representative of the
performance of the whole system. Its relationship with
Birnbaum’s measure is analyzed, and the ranking of
components given by both measures are compared. These
rankings happen to be equal when all components have the
same reliability but different in general. In contrast with
Birnbaum’s, the Representativeness reliability importance
measure of a component does depend on its reliability.