European Conference on Operational Research

p. 78

Presentation's date: 2019-06-24

Abstract:

Different power indices defined in simple games can be obtained under a similar probabilistic approach by: 1) establishing a bargaining model, 2) deciding which kind of winning coalitions are assumed to be formed. The power indices which can be defined under this approach include, among others, the well-known Banzhaf, Johnston or DeeganPackel índices. When extending these power indices to (3,2)-games a third important aspect must also be considered: the notion of criticality which should be used.]]>

European Conference on Operational Research

p. 46

Presentation's date: 2019-06-24

Abstract:

Coalitional multinomial values were introduced by Carreras and Puente in 2015. Each one of them depends on n parameters, which are interpreted as players’ individual tendencies to form coalitions, so these values are designed to take into account players’ attitudes with regard to cooperation. They combine the Shapley value and the corresponding multinomial probabilistic value (Freixas and Puente, 2002). They first apply this latter value to the quotient game and obtain a payoff for each union; next, they apply within each union the Shapley value to a reduced game, played in the union, for sharing that payoff efficiently. This looks highly interesting for a voting setup since, once an alliance is formed -and, especially, if it supports a coalition government-, cabinet ministries, parliamentary and institutional positions, budget management and other political responsibilities have to be distributed among the members of the coalition efficiently, whence in a way as close as possible to the one suggested by the Shapley value. This family lies in the class of probabilistic values, widely generalizes the symmetric coalitional binomial semivalues (Carreras and Puente, 2012) and provides a promising framework for applications. In this work a new axiomatic characterization of each coalitional multinomial value with positive profile is obtained by just replacing the property of symmetry within unions with the property of balanced contributions within unions.]]>

European Conference on Operational Research

p. 77

Presentation's date: 2019-06-24

Abstract:

We introduce a subfamily of bisemivalues called (p,q)-bisemivalues and as a particular case of it, we find the binomial bisemivalues, that extend the concept of binomial values to bicooperative games. The (p,q)-bisemivalues can be used in the study of bicooperative games because they offer a deal of flexibility greater than the values defined up to now, and hence many more possibilities to introduce additional information when evaluating a game. They provide tools to study not only games in abstracto(i.e. from a merely structural viewpoint) but also the influence of players’ personality on the issue. In the (p,q)- bisemivalue case two parameters are used to cope with different attitudes the players may hold when playing a given game, even if they are not individuals but countries, enterprises, parties, tradeunions, or collectivities of any other kind. For all player, we will attach to parameter p the meaning of generical tendency to support a player in his decision and to parameter q generical tendency to go against him. We think that these bisemivalues are suited for the study of bicooperative games where players show two different tendencies to form coalitions. Players’ tendencies can encompass a variety of situations that cannot be analyzed, without modifying the game, by means of another values, which are concerned only with the structure of the game. We also give a computational procedure in terms of the multilinear extension of the game to calculate them.]]>

International Congress on Education & Learning

Presentation's date: 2019-06-21

Abstract:

Typically, the test type exams with binary answers per question of the type: true / false are corrected granting a +1 to the correct answers and a -1 to those that are not. This mainly obeys to a purely statistic criterion. From our point of view this method of qualication is not suitable and therefore should be amended as soon as possible. In this work we propose two alternative methods that seek to favor good students to the detriment of those who tend to speculate by randomly answering questions of which they do not know the answer. The two methods we propose benefit students who do not answer questions randomly. The second one does not harm them with respect to the classical method of granting +1 per correct answer and -1 per incorrect answer. The proposals made extend to multiple choice exams with an arbitrary and fixed number of answers for each question with a single answer being correct per question.]]>

Knowledge-based systems

Vol. 174, p. 144-159

DOI: 10.1016/j.knosys.2019.03.005

Date of publication: 2019-06-15

Abstract:

We introduce collective decision-making models associated with influence spread under the linear threshold model in social networks. We define the oblivious and the non-oblivious influence models. We also introduce the generalized opinion leader–follower model (gOLF) as an extension of the opinion leader–follower model (OLF) proposed by van den Brink et al. (2011). In our model we allow rules for the final decision different from the simple majority used in OLF. We show that gOLF models are non-oblivious influence models on a two-layered bipartite influence digraph. Together with OLF models, the satisfaction and the power measures were introduced and studied. We analyze the computational complexity of those measures for the decision models introduced in the paper. We show that the problem of computing the satisfaction or the power measure is #P-hard in all the introduced models even when the subjacent social network is a bipartite graph. Complementing this result, we provide two subfamilies of decision models in which both measures can be computed in polynomial time. We show that the collective decision functions are monotone and therefore they define an associated simple game. We relate the satisfaction and the power measures with the Rae index and the Banzhaf value of an associated simple game. This will allow the use of known approximation methods for computing the Banzhaf value, or the Rae index to their practical computation.]]>

Journal of combinatorial theory. Series B

Vol. 136, p. 289-328

DOI: 10.1016/j.jctb.2018.11.002

Date of publication: 2019-05

Abstract:

We introduce the (G,H)-isomorphism game, a new two-player non-local game that classical players can win with certainty iff the graphs G and H are isomorphic. We then define quantum and non-signalling isomorphisms by considering perfect quantum and non-signalling strategies for this game. We prove that non-signalling isomorphism coincides with fractional isomorphism, giving the latter an operational interpretation. We show that quantum isomorphism is equivalent to the feasibility of two polynomial systems obtained by relaxing standard integer programs for graph isomorphism to Hermitian variables. Finally, we provide a reduction from linear binary constraint system games to isomorphism games. This reduction provides examples of quantum isomorphic graphs that are not isomorphic, implies that the tensor product and commuting operator frameworks result in different notions of quantum isomorphism, and proves that both relations are undecidable.]]>

European Meeting on Game Theory

p. 10

Presentation's date: 2019-04-02

Abstract:

A number of citation indices have been proposed for measuring and ranking the research publication records of scholars.Some of the best known indices, such as that proposed by Hirsch and Woeginger, are designed to reward most highlythose records x that strike some balance between productivity P (number of publications) and impact I (frequency withwhich ones papers are cited); a large number of rarely cited publications will not score well, nor will a very small numberof heavily cited papers.We propose some new citation indices that share common properties and that present severaladvantages with respect to the most used one, the Hirsh index. We mainly focus in one of them which is axiomaticallycharacterized by a set of axioms that have a close relationship, in discrete version, with the bipersonal bargainingcooperative model by Nash. Among the list of advantages, when compared with the Hirsh index, of the proposed indexwe find:It produces fairer ranking within subdisciplines,Improved decisiveness, fewer ties and more dynamic,The improvedgrow over time via increments that are both more frequent are smaller,Enhanced centrality and tail balancedness.]]>

European Meeting on Game Theory

p. 9

Presentation's date: 2019-04-02

Abstract:

Some power indices defined in simple games can be obtained under a similar probabilistic approach by: 1) establishinga bargaining model, 2) deciding which kind of winning coalitions are assumed to be formed. The power indices whichcan be defined under this approach include, among others, the well-known Banzhaf, Johnston or Deegan-Packel ´indices.When extending these power indices to (3,2)-games a third important aspect must also be considered: the notion ofcriticality to be used.]]>

Applied mathematics and optimization

Vol. 79, num. 2, p. 309-326

DOI: 10.1007/s00245-017-9439-8

Date of publication: 2019-04

Abstract:

In this paper we analyze an homogeneous and isotropic mixture of viscoelastic solids. We propose conditions to guarantee the coercivity of the internal energy and also of the dissipation, first in dimension two and later in dimension three. We obtain an uniqueness result for the solutions when the dissipation is positive and without any hypothesis over the internal energy. When the internal energy and the dissipation are both positive, we prove the existence of solutions as well as their analyticity. Exponential stability and impossibility of localization of the solutions are immediate consequences.

The final publication is available at link.springer.com via https://doi.org/10.1007/s00245-017-9439-8]]>

Social choice and welfare

Vol. 52, num. 4, p. 607-634

DOI: 10.1007/s00355-018-1164-y

Date of publication: 2019-04

Abstract:

The Nakamura number is an appropriate invariant of a simple game to study the existence of social equilibria and the possibility of cycles. For symmetric (quota) games its number can be obtained by an easy formula. For some subclasses of simple games the corresponding Nakamura number has also been characterized. However, in general, not much is known about lower and upper bounds depending on invariants of simple, complete or weighted games. Here, we survey such results and highlight connections with other game theoretic concepts. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.

This is a post-peer-review, pre-copyedit version of an article published in Social choice and welfare. The final authenticated version is available online at: http://dx.doi.org/10.1007/s00355-018-1164-y.]]>

Asymptotic analysis

Vol. 112, num. 3-4, p. 151-164

DOI: 10.3233/ASY-181500

Date of publication: 2019-04-01

Abstract:

In this paper we analyze the system of equations that models the behaviour of materials with a double porous structure. We introduce dissipation mechanisms in both structures. We show existence, uniqueness and analyticity for the solutions of the system. As consequences, exponential stability and impossibility of localization for the solutions are obtained.]]>

Discrete applied mathematics

Vol. 255, p. 21-39

DOI: 10.1016/j.dam.2018.07.032

Date of publication: 2019-02-28

Abstract:

Voting games with abstention are voting systems in which players can cast not only yes and no vote, but are allowed to abstain. This paper centers on the structure of a class of complete games with abstention. We obtain, a parameterization that can be useful for enumerating these games, up to isomorphism. Indeed, any I-complete game is determined by a vector of matrices with non-negative integers entries. It also allows us determining whether a complete game with abstention is a strongly weighted (3, 2) game or not, and for other purposes of interest in game theory.]]>

International Conference on Operations Research and Enterprise Systems

p. 45-52

DOI: 10.5220/0007297000450052

Presentation's date: 2019-02-20

Abstract:

This work focuses on the Owen value and the Owen-Banzhaf value, two classical concepts of solution defined on games with structure of coalition blocks. We provide a computation procedure for these solutions based on a method of double-level work obtained from the multilinear extension of the original game. Moreover, two applications to several possible political situations in the Madrid Assembly and the Andalusian Parliament (legislatures 2015-2019) are also given.]]>

Atmospheric chemistry and physics

Vol. 19, p. 523-542

DOI: 10.5194/acp-19-523-2019

Date of publication: 2019-01-14

Abstract:

Aerosol radiative properties are investigated in southeastern Spain during a dust event on June 16-17, 2013 in the framework of the ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment /Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) campaign. Particle optical and microphysical properties from ground-based sun/sky photometer and lidar measurements, as well as in situ measurements onboard the SAFIRE ATR 42 French research aircraft are used to create a set of different levels of input parameterizations, which feed the 1-D radiative transfer model (RTM) GAME (Global Atmospheric ModEl). We consider three datasets: 1) a first parameterization based on the retrievals by an advanced aerosol inversion code (GRASP; Generalized Retrieval of Aerosol and Surface Properties) applied to combined photometer and lidar data; 2) a parameterization based on the photometer columnar optical properties and vertically-resolved lidar retrievals with the two-component Klett-Fernald algorithm; and 3) a parameterization based on vertically-resolved optical and microphysical aerosol properties measured in situ by the aircraft instrumentation. Once retrieved, the outputs of the RTM in terms of both shortwave and longwave radiative fluxes are compared against ground and in situ airborne measurements. In addition, the outputs of the model in terms of the aerosol direct radiative effect are discussed with respect to the different input parameterizations. Results show that calculated atmospheric radiative fluxes differ no more than 7 % to the measured ones. The three parameterization datasets produce a cooling effect due to mineral dust both at the surface and the top of the atmosphere. Aerosol radiative effects with differences up to 10 W·m-2 in the shortwave spectral range (mostly due to differences in the aerosol optical depth), and 2 W·m-2 for the longwave (mainly due to differences in the aerosol optical depth but also to the coarse mode radius used to calculate the radiative properties) are obtained when comparing the three parameterizations. The study reveals the complexity of parametrizing 1-D RTMs as sizing and characterising the optical properties of mineral dust is challenging. The use of advanced remote sensing data and processing, in combination with closure studies on the optical/microphysical properties from in situ aircraft measurements when available, is recommended.]]>

DOI: 10.1007/978-3-319-92204-1

Date of publication: 2019

Abstract:

This book reports on the implementation of evolutionary-game theory in the design of distributed optimization-based controllers. First, it discusses how the classical population-game approach can contribute to and complement the design of optimization-based controllers. It shows how the features of this approach can be exploited to extend their capabilities in the solution of distributed optimization problems, and examines density games in order to consider multiple coupled constraints and preserve the non-centralized information requirements. Furthermore, it establishes a close relationship between the possible interactions among agents in a population with constrained information sharing among different local controllers. It also discusses coalitional games, focusing on the Shapley power index and proposes an alternative method of computing the latter, which reduces computational time, as well as a different way of finding it using distributed communication structures. All the proposed strategies are then tested on various control problems, such as those related to the Barcelona water supply network, multiple continuous stirred tank reactors, various unmanned aerial vehicle systems, and a water distribution system. This thesis, examined at the Universitat Politècnica de Catalunya and Universidad de los Andes in 2017, received the award for best thesis in control from the control group of the Spanish Committee of Automatic Control (CEA) in the same year.]]>

Journal of computational and applied mathematics

Vol. 345, p. 247-268

DOI: 10.1016/j.cam.2018.06.045

Date of publication: 2019-01-01

Abstract:

In this paper, we analyse a model involving a strain gradient thermoelastic rod with voids. Existence and uniqueness, as well as an energy decay property, are proved by means of the semigroup arguments. The variational formulation is derived and then, a fully discrete approximation is introduced by using the finite element method to approximate the spatial variable and the implicit Euler scheme to discretize the time derivatives. A stability result and a priori error estimates are obtained, from which the linear convergence of the algorithm is deduced under suitable additional regularity conditions. Finally, some numerical simulations are presented to demonstrate the accuracy of the algorithm and the behaviour of the solution.]]>

DOI: 10.1007/978-3-319-89890-2

Date of publication: 2019

Abstract:

This book contains thirty-five selected papers presented at the International Conference on Evolutionary and Deterministic Methods for Design, Optimization and Control with Applications to Industrial and Societal Problems (EUROGEN 2017). This was one of the Thematic Conferences of the European Community on Computational Methods in Applied Sciences (ECCOMAS). Topics treated in the various chapters reflect the state of the art in theoretical and numerical methods and tools for optimization, and engineering design and societal applications. The volume focuses particularly on intelligent systems for multidisciplinary design optimization (mdo) problems based on multi-hybridized software, adjoint-based and one-shot methods, uncertainty quantification and optimization, multidisciplinary design optimization, applications of game theory to industrial optimization problems, applications in structural and civil engineering optimum design and surrogate models based optimization methods in aerodynamic design.]]>

International game theory review

Vol. 21, num. 1, 1940001

DOI: 10.1142/S0219198919400012

Date of publication: 2019-01-01

Abstract:

The aim of this work is to give a characterization of the Shapley–Shubik and the Banzhaf power indices for (3,2)-simple games. We generalize to the set of (3,2)-simple games the classical axioms for power indices on simple games: transfer, anonymity, null player property and efficiency. However, these four axioms are not enough to uniquely characterize the Shapley–Shubik index for (3,2)-simple games. Thus, we introduce a new axiom to prove the uniqueness of the extension of the Shapley–Shubik power index in this context. Moreover, we provide an analogous characterization for the Banzhaf index for (3,2)-simple games, generalizing the four axioms for simple games and adding another property.

Electronic version of an article published as International Game Theory Review, Vol. 21, Issue 1, 1940001, 2019, p. 1-24. DOI: 10.1142/S0219198919400012] © World Scientific Publishing Company https://www-worldscientific-com.recursos.biblioteca.upc.edu/doi/abs/10.1142/S0219198919400012]]>

Journal of evolution equations

Vol. 18, num. 4, p. 1697-1712

DOI: 10.1007/s00028-018-0457-z

Date of publication: 2018-12

Abstract:

We investigate the well-posedness and the stability of the solutions for several Taylor approximations of the phase-lag two-temperature equations.We give conditions on the parameters which guarantee the existence and uniqueness of solutions as well as the stability and the instability of the solutions for each approximation]]>

Journal of Systems Science & Complexity

Vol. 31, num. 6, p. 1571-1590

DOI: 10.1007/s11424-018-7163-3

Date of publication: 2018-12

Abstract:

In recent years, there are many crimes related drug fraud occuring in China and many experts think that the main cause is that China Food and Drug Administration (CFDA) adopts announced inspection (AI). In order to circumvent this difficulty, CFDA has exploited unannounced inspection (UI) since 2014. In this paper, the authors study the problem of which one performs better, AI or UI. Specifically, the authors consider a supervisor, which decides the inspection approach, inspection strength and punishment to force the firm to put self-inspection effort to meet the requirements of Good Manufacturing Practice, and a firm, which produces a drug and decides its self-inspection effort. The authors use game theory to model this problem, characterize the equilibrium policies under AI, and compare the effects of the two approaches on preventing drug fraud under complete and incomplete information. The results show that under the complete information, UI performs better if the firm’s technical level and the inspection cost are low and AI performs better otherwise. When the supervisor doesn’t know the firm’s technical level, if the low technical level is high, AI performs better. Otherwise, UI performs better if the inspection cost is low and AI performs better if the inspection cost is high]]>

Quantitative methods of group decision making

Presentation's date: 2018-11-23

Abstract:

A new class of weighted games, clled basic games, is introduced. The goal of the present comunication is to show that, if a particular ranking of power has to be designed, the class of basic games can be always used for this purpose with very few exceptions. In fact, it is proved that all hierarchies which are achievable in weighted games are also achievable in basic games. This is a nice result because the class of basic games is considerably smaller than the class of weighted games.]]>

Quantitative methods of group decision making

Presentation's date: 2018-11-23

Abstract:

It is shown that different power indices defined in simple games can be obtained under a similar probabilistic approach: 1) establishing a bargaining model and 2) deciding which kind of winning coalitions are assumed to be formed. The power indices defined with this model include, among others, the well-known Banzhaf, Johnston or Deegan-Packel indices]]>

Transactions on computational collective intelligence

Vol. 30, p. 178-199

DOI: 10.1007/978-3-319-99810-7_9

Date of publication: 2018-11

Abstract:

Very often in some censorious healthcare scenario, there may be a need to have some expert consultancies (especially by doctors) that are not available in-house to the hospitals. Earlier, this interesting healthcare scenario of hiring the expert consultants (mainly doctors) from outside of the hospitals had been studied with the robust concepts of mechanism design with money and mechanism design without money. In this paper, we explore the more realistic two sided matching market in our healthcare set-up. In this, the members of the two participating communities, namely the patients and the doctors are revealing the strict preference ordering over the members of the opposite community for a stipulated amount of time. We assume that the patients and doctors are strategic in nature. With the theoretical analysis, we demonstrate that the TOMHECs, that results in the stable allocation of doctors to the patients, satisfies the several economic properties such as strategy-proof-ness (or truthfulness) and optimality. Further, the analytically based analysis of our proposed mechanisms i.e. RAMHECs and TOMHECs are carried out on the ground of the expected distance of the allocation done by the mechanisms from the top most preference. The proposed mechanisms are also validated with the help of exhaustive experiments.]]>

Zeitschrift für angewandte Mathematik und Physik

Vol. 69, num. 5, p. 129-1-129-8

DOI: 10.1007/s00033-018-1023-9

Date of publication: 2018-10

Abstract:

In this paper we consider the type III thermoelastic theory with microtemperatures. We study the time decay of the solutions and we prove that under suitable conditions for the constitutive tensors, the solutions decay exponentially. This fact is in somehow shocking because it differs from the behavior of the solutions in the classical model of thermoelasticity with microtemperatures]]>

Games and economic behavior

Vol. 113, p. 248-261

DOI: 10.1016/j.geb.2018.09.005

Date of publication: 2018-09-19

Abstract:

We analyze assortative assignment games, introduced in Becker (1973) and Eriksson et al. (2000). We study the extreme core points and show an easy way to compute them. We find a natural solution for these games. It coincides with several well-known point solutions, the median stable utility solution (Schwarz and Yenmez, 2011) and the nucleolus (Schmeidler, 1969). We also analyze the behavior of the Shapley value. We finish with some extensions, where some hypotheses are relaxed.]]>

Public choice

Vol. 176, num. 3-4, p. 1-9

DOI: 10.1007/s11127-018-0560-2

Date of publication: 2018-09-01

Abstract:

In 1996, Felsenthal and Machover proposed a bargaining procedure for a valuable payoff in cooperative and simple games. They proved that the value underlying their bargaining scheme was the Shapley value by showing that it verifies the axioms that Shapley proposed for characterizing his value. They remarked that a direct proof of the result involves rather formidable combinatorial difficulties, but that it has some independent interest. In this paper, we prove such a combinatorial result and obtain a formula for the Shapley value that has a great potential to be extended to more general classes of games.

This is a post-peer-review, pre-copyedit version of an article published in Public choice. The final authenticated version is available online at: http://dx.doi.org/10.1007/s11127-018-0560-2.]]>

IEEE International Symposium on Robot and Human Interactive Communication

Presentation's date: 2018-08-29

Abstract:

This study examines patterns of coordinated gaze between a child and a robot (NAO) during a card matching game, ‘Memory’. Dyadic gaze behavior like mutual gaze, gaze following and joint attention are indications both of child’s engagement with the robot and of the quality of child-robot interaction. Eighteen children interacted with a robot tutor in two settings. In the first setting, the robot tutor gave clues to assist children in finding the matching cards, and in the other setting, the robot tutor only looked at the participants during the play. We investigated the coordination between child and robots’ gaze behaviors. We found that more occurrences of mutual gaze and gaze following made the children aware of the gaze hints given by the robot and improved the efficacy of the robot tutor as a helping agent. This study, therefore, provides guidelines for gaze behaviors design to enrich child-robot interaction in a tutoring context.]]>

Mathematics and mechanics of solids

p. 1-16

DOI: 10.1177/1081286518783219

Date of publication: 2018-07-20

Abstract:

In this paper we consider the one-dimensional version of thermoelasticity with two porous structures and porous dissipation on one or both of them. We first give an existence and uniqueness result by means of semigroup theory. Exponential decay of the solutions is obtained when porous dissipation is assumed for each porous structure. Later, we consider dissipation only on one of the porous structures and we prove that, under appropriate conditions on the coefficients, there exists undamped solutions. Therefore, asymptotic stability cannot be expected in general. However, we are able to give suitable sufficient conditions for the constitutive coefficients to guarantee the exponential decay of the solutions.]]>

Spain-Italy-Netherlands Meeting on Game Theory

p. 23

Presentation's date: 2018-07-16

Abstract:

Simple majority is a very common rule to make collective decisions in a voting context. Following this rule, each individual can either be in favor of the proposal (represented by input 1), be indifferent to it (input 0), or be against it (input -1). The proposal is approved (output 1) if the number of votes in favor of it is greater than the number of votes against it, it is rejected (output -1) in the opposite case, and there may be a tie (output 0) if the number of votes for both sides coincides. May’s well-known result axiomatically characterizes simple majority rule in this context. A more general situation is considered here: several symmetric degrees of positive and negative support for the submitted proposal are allowed to voters, so that the voting rules considered by May to characterize the simple majority rule correspond to a particular case. The main contribution of this work provides a set of independent axioms which uniquely characterizes a function that has all the ingredients of the simple majority rule and coincides with it when the support or rejection to the proposal can only be manifested in one way. A relevant aspect is that when we are restricted to the particular case our set of axioms does not coincide with those by May, so that they constitute a new characterization of the simple majority rule. Situations in which different degrees of voting options are possible appear in different contexts. Among them: evaluations of athletes in some sports competitions, evaluations of students, credit ratings of financial entities or countries, referendums, evaluations of the quality offered in a service by a team or individual, etc.]]>

Spain-Italy-Netherlands Meeting on Game Theory

p. 49-50

Presentation's date: 2018-07-16

Abstract:

Boolean functions assign a binary output to any vector of binary components. Monotonic simple games are monotonic Boolean functions, components correspond to voters, coalitions are in one-to-one correspondence with binary vectors and the output indicates if the coalition is either winning or losing. Boolean functions extend to discrete functions in which several values for the variables and several values for the output are allowed. Such functions can be formalized to the so-called (j,k)-functions and we are mainly devoted to those that are monotonic. Still two subclasses deserve our attention: anonymous and threshold (j,k)-functions. We study their relationship and, remarkably, we find that the link between these two subclasses depends on j but not on k. As a consequence, the enumeration of anonymous (2,k)-functions is obtained, and it is given by a nice closed formula. We highlight the applicability of the considered functions to the contexts of anonymous or weighted voting systems and that of the reliability of systems in which replaceable components are involved.]]>

European Conference on Operational Research

p. 111

Presentation's date: 2018-07-09

Abstract:

Simple majority is a very common rule to make collective decisions in a voting context. Following this rule, each individual can either be in favor of the proposal (represented by input 1), be indifferent to it (input 0), or be against it (input -1). The proposal is approved (output 1) if the number of votes in favor of it is greater than the number of votes against it, it is rejected (output -1) in the opposite case, and there may be a tie (output 0) if the number of votes for both sides coincides. May’s well-known result axiomatically characterizes simple majority rule in this context. A more general situation is considered here: several symmetric degrees of positive and negative support for the submitted proposal are allowed to voters, so that the voting rules considered by May to characterize the simple majority rule correspond to a particular case. The main contribution of this work provides a set of independent axioms which uniquely characterizes a function that has all the ingredients of the simple majority rule and coincides with it when the support or rejection to the proposal can only be manifested in one way. A relevant aspect is that when we are restricted to the particular case our set of axioms does not coincide with those by May, so that they constitute a new characterization of the simple majority rule. Situations in which different degrees of voting options are possible appear in different contexts. Among them: evaluations of athletes in some sports competitions, evaluations of students, credit ratings of financial entities or countries, referendums, evaluations of the quality offered in a service by a team or individual, etc.]]>

European Conference on Operational Research

p. 110

Presentation's date: 2018-07-02

Abstract:

An influence game is a cooperative simple game in which a coalition of the players wins if it is able to convince enough agents to participate in the task (to vote in favor of a decision). In this vein, the linear threshold model is taken as the influence model. It is known that influence games capture the class of simple games. Influence games (as simple games) are monotonic. Now, we present some new classes of influence games under some connectivity restrictions over winning coalitions. These classes of influence games are not necessary monotonic. We characterize the computational complexity of problems on influence games over these new classes, including measures (length and width), values (Shapley-Shubik and Banzhaf) and properties (of teams and players). We also analyze those problems for some particular extremal cases, with respect to the propagation of influence.]]>

Electronic notes in discrete mathematics

Vol. 68, p. 197-202

DOI: 10.1016/j.endm.2018.06.034

Date of publication: 2018-07

Abstract:

We consider decision models associated with cooperative influence games, the oblivious and the non-oblivious influence models. In those models the satisfaction and the power measures were introduced and studied. We analyze the computational complexity of those measures when the in uence level is set to unanimity and the rule of decision is simple majority. We show that computing the satisfaction and the power measure in those systems are #P-hard.]]>

Chaotic Modeling and Simulation

num. 3, p. 285-294

Date of publication: 2018-07

Abstract:

We study qualitative properties of the solutions of the system of partial differential equations modeling thermomechanical deformations for mixtures of thermoelastic solids when the theory of Green and Lindsay for the heat conduction is considered. Three dissipation mechanisms are proposed in the system: thermal dissipation, viscosity eects on one constituent of the mixture and damping in the relative velocity of the two displacements of both constituents. First, we prove the existence and uniqueness of the solutions. Later we prove the exponential stability of the solutions over the time. We use the semigroup arguments to establish our results

We study qualitative properties of the solutions of the system of partial differential equations modeling thermomechanical deformations for mixtures of thermoelastic solids when the theory of Green and Lindsay for the heat conduction is considered. Three dissipation mechanisms are proposed in the system: thermal dissipation, viscosity e ects on one constituent of the mixture and damping in the relative velocity of the two displacements of both constituents. First, we prove the existence and uniqueness of the solutions. Later we prove the exponential stability of the solutions over the time. We use the semigroup arguments to establish our results]]>

IEEE International Geoscience and Remote Sensing Symposium

p. 6033-6036

DOI: 10.1109/IGARSS.2018.8517278

Presentation's date: 2018-07

Abstract:

A 1-D radiative transfer study is presented based on the measurements performed at Granada during a dust event within the framework of the ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Forcing on the Mediterranean Climate) campaign, during June 16-17, 2013. Ground-based AERONET and lidar measurements were performed and further processed with the GRASP algorithm to get spectrally-resolved profiles of extinction and single scattering albedo. Furthermore, the research aircraft ATR-42 made two flights above Granada providing vertical profiles of aerosol optical and microphysical properties together with measurements of broadband radiative fluxes. All of the ground-based and aircraft aerosol properties are used as input in the radiative transfer model GAME in order to evaluate its sensitivity to different input datasets. The aircraft fluxes are used for validation of the modelled ones.]]>

International Conference on Chaotic Modeling and Simulation

p. 74

Presentation's date: 2018-06-07

Abstract:

The aim of the present communication is the study of the time decay of solutions for the one-dimensional phase-lag thermoelasticity with two temperatures. In a recent contribution [1] the authors studied the stability of the solutions determined by several models of the phase-lag heat conduction with two temperatures. Suitable conditions to guarantee the stability (instability) of the solutions were obtained there. We here want to extend the analysis to the one-dimensional thermoelastic problem]]>

International Conference on Chaotic Modeling and Simulation

p. 38

Presentation's date: 2018-06-07

Abstract:

: In the last years, a big interest has been developed to understand the time decay of solutions for the porous thermoelasticity with different thermal mechanisms. We here want to consider the problem of the one-dimensional porous thermoelasticity when the heat conduction is given by means of the dual-phase-lag theory. We want to give suitable conditions in order to guarantee that the decay of solutions is controlled by a negative exponential. We also want to provide conditions for the slow decay of the solutions.]]>

Group decision and negotiation

Vol. 27, num. 3, p. 467-502

DOI: 10.1007/s10726-018-9570-1

Date of publication: 2018-06

Abstract:

This paper aims to develop, for any cooperative game, a solution notion that enjoys stability and consists of a coalition structure and an associated payoff vector derived from the Shapley value. To this end, two concepts are combined: those of strong Nash equilibrium and Aumann--Dr\`{e}ze coalitional value. In particular, we are interested in conditions ensuring that the grand coalition is the best preference for all players. Monotonicity, convexity, cohesiveness and other conditions are used to provide several theoretical results that we apply to numerical examples including real--world economic situations.]]>

Congreso Nacional de Estadística e Investigación Operativa. Jornadas de Estadística Pública

p. 188

Presentation's date: 2018-06-01

Abstract:

Boolean functions assign a binary output to any vector of binary components. Monotonic simple games are monotonic Boolean functions, components correspond to voters, coalitions are in one-to-one correspondence with binary vectors and the output indicates if the coalition is either winning or losing. Boolean functions extend to discrete functions in which several values for the variables and several values for the output are allowed. Such functions can be formalized to the so-called (j,k)-functions and we are mainly devoted to those that are monotonic. Still two subclasses deserve our attention: anonymous and threshold (j,k)-functions. We study their relationship and, remarkably, we find that the link between these two subclasses depends on j but not on k. As a consequence, the enumeration of anonymous (2,k)-functions is obtained, and it is given by a nice closed formula. We highlight the applicability of the considered functions to the contexts of anonymous or weighted voting systems and that of the reliability of systems in which replaceable components are involved.]]>

Congreso Nacional de Estadística e Investigación Operativa. Jornadas de Estadística Pública

p. 124

Presentation's date: 2018-05-30

Abstract:

Each semivalue, as a solution concept defined on cooperative games with a finite set of players, is univocally determined by weighting coefficients that apply to players’ marginal contributions. Taking into account that a semivalue induces semivalues on lower cardinalities, we prove that its weighting coefficients can be reconstructed from the last weighting coefficients of its induced semivalues. Moreover, we provide the conditions of a sequence of numbers in order to be the family of the last coefficients of any induced semivalues. As a consequence of this fact, we give two characterizations of each semivalue defined on cooperative games with a finite set of players: one, among all semivalues; another, among all solution concepts on cooperative games.]]>

Congreso Nacional de Estadística e Investigación Operativa. Jornadas de Estadística Pública

p. 125-

Presentation's date: 2018-05-30

Abstract:

En este trabajo nos centramos en los juegos bicooperativos, una variación de los juegos cooperativos clásicos, presentamos varias propiedades para valores en juegos bicooperativos con respecto a jugadores nulos y no nulos, contribuciones equilibradas, dominancia, monotonía y sensibilidad, que son paralelas a las propiedades estándar existentes en la literatura sobre teoría de valores, para valores en juegos cooperativos. También estudiamos el comportamiento de los bisemivalores con respecto a ellas, surgiendo de forma natural la caracterización de alguna subfamilia de los bisemivalores, como una condición conveniente para garantizar la validez de algunas de ellas.]]>

Congreso Nacional de Estadística e Investigación Operativa. Jornadas de Estadística Pública

p. 124-125

Presentation's date: 2018-05-30

Abstract:

Simple majority is a very common rule to make collective decisions in a voting context. Following this rule, each individual can either be in favor of the proposal, be indifferent to it, or be against it. The proposal is approved if the number of votes in favor of it is greater than the number of votes against it, it is rejected in the opposite case, and there may be a tie if the number of votes for both sides coincide. May’s well-known result axiomatically characterizes simple majority rule in this context. A more general situation is considered here: several symmetric degrees of positive and negative support for the submitted proposal are allowed to voters, so that the voting rules considered by May to characterize the simple majority rule correspond to a particular case. The main contribution of this work provides a set of independent axioms which uniquely characterizes a function that has all the ingredients of the simple majority rule and moreover it gives a different version of May’s result.]]>

Congreso Nacional de Estadística e Investigación Operativa. Jornadas de Estadística Pública

p. 124-

Presentation's date: 2018-05-30

Abstract:

We introduce a subfamily of bisemivalues called (p,q)-bisemivalues and, as a particular case of it, we find the binomial bisemivalues, that extend the concept of binomial values to bicooperative games. They provide tools to study not only games in abstracto (i.e. from a merely structural viewpoint) but also the influence of players' personality on the issue. In the (p,q)-bisemivalue case two parameters are used to cope with different attitudes the players may hold when playing a given game. For all player, we will attach to parameter p the meaning of generical tendency to support a player in his decision and to parameter q generical tendency to go against him. We prove that their weighting coefficients are in geometric progression, the simplest form of monotonicity. We also give a computational procedure in terms of the multilinear extension of the game to calculate them.]]>

Balkan Conference on Operational Research

p. B6

Presentation's date: 2018-05-27

Abstract:

Given n players, a simple game is a 0/1 valued TU cooperative game verifying unanimity and monotonicity. In such a game, a coalition, i.e., a subset of players, always wins (winning coalition) or loses (losing coalition). It is known that each simple simple can be expressed as the intersection (or the union) of weighted voting games. A simple game is called weighted voting (majority) game if there is a quote q and an assignment of a non-negative integer weight to each player in such a way that a coalition is winning if and only if the sum of the weights of its players is greater than or equal to the integer quota q. Two important and well studied concepts relating simple games with weighted games are the dimension and the codimension. The dimension is the minimum number of weighted games such that their intersections generate the considered simple game. In the same vein, the codimension is the minimum number of weighted games such that their unions generate the considered simple game. There are some previous studies about the dimension and the codimension of simple games. Nevertheless no complete classification of dimension or codimension of simple games is known even for small number of players. In this work we initiate a systematic such classification with respect to the dimension and the codimension parameters. We introduce the concept of multidimension of a simple game, the minimum number of intersections and unions of weighted games to generate the considered simple game. A similar concept was introduced in another topic (Boolean functions) by Goldberg. We also classify some simple games with respect to their multidimension. Moreover, we present some particular results of the dimension, the codimension and the multidimension for specific simple games depending on properties of the (minimal) winning coalitions. Finally, we study possible relations between k-trade robustness and k-invarinat-trade robustness (concepts that characterize the subclass of simple games called complete simple games) with respect to the dimension, the codimension and the multidimension.]]>

International Conference on Artificial Intelligence Applications and Innovations

p. 78-88

DOI: 10.1007/978-3-319-92016-0_8

Presentation's date: 2018-05

Abstract:

The management of future networks is expected to fully exploit cognitive capabilities that embrace knowledge and intelligence, increasing the degree of automation, making the network more self-autonomous and enabling a personalized user experience. In this context, this paper presents the use of knowledge-based capabilities through a specific lab experiment focused on the Channel Selection functionality for Cognitive Radio Networks (CRN). The selection is based on a supervised classification that allows estimating the number of interfering sources existing in a given frequency channel. Four different classifiers are considered, namely decision tree, neural net-work, naive Bayes and Support Vector Machine (SVM). Additionally, a comparison against other channel selection strategies using Q-learning and game theory has also been performed. Results obtained in an illustrative and realistic test scenario have revealed that all the strategies allow identifying an optimum solution. However, the time to converge to this solution can be up to 27 times higher according to the algorithm selected.]]>

Risk 2018- 7th Workshop on Risk Management and Insurance

p. 135-142

Presentation's date: 2018-04-27

Abstract:

In this post recession time it is important to measure the possibilities offered by a society in relation to investments. To do that, we consider an investment schema I= (R;R_1,...,R_n) where R is a lower bound on the desired return and the R_i's are the return of the assets (to invest in). We introduce "the power to invest" , denoted by Power(I), a measure of the capability of the schema to fulfilling the requirement R. The power to invest is inspired in the Coleman's power of a collectivity to act. We consider the angel-daemon approach to uncertainty and extend it to investment schemas. The approach tries to tune cases in-between the worst and the best scenarios and analyze them through game theory. We show how to use the power to invest to asses uncertainty in such situations and develop several examples.

In this post recession time it is important to measure the possibilities offered by a society in relation to investments. To do that, we consider an investment schema I= (R;R_1,...,R_n) where R is a lower bound on the desired return and the R_i's are the return of the assets (to invest in). We introduce]]>

Meeting of the European Working Group on Multicriteria Decision Aiding

p. 37-

Presentation's date: 2018-04-06

Abstract:

In social network analysis, there is a common perception that influence is relevant to determine the global behavior of the society and thus it can be used to enforce cooperation by targeting an adequate initial set of individuals or to analyze global choice processes. The aim of this paper is to propose centrality measures that can be used to analyze the relevance of the participants in process related to spread of influence on . In previous papers it was considered a multiagent system in which the agents are eager to perform a collective task but where their real engagement depends on the perception of the willingness to perform the task of other individuals. The setting is modeled and analized using a notion of simple games called influence games. Those games are defined on graphs were the nodes are labeled by their influence threshold and the spread of influence between its nodes is used to determine whether a coalition is winning or not. Influence games provide additional tools to measure the importance of the actors of a social network by means of classic power indices and provide a framework to consider new centrality criteria. In this work, we consider classical power indices as centrality measure in specific scenario of game-theoretic networks. Furthermore, we define new centrality measures such as satisfaction and effort that, as far as we know, have not been considered so far. Besides the definition we perform a comparison of the proposed measures with other three classic centrality measures, degree, closeness and betweenness. To perform the comparison we consider three social networks. We show that in some cases our measurements provide centrality hierarchies similar to those of other measures, while in other cases provide different hierarchies.]]>

TOP

Vol. 26, num. 1, p. 164-186

DOI: 10.1007/s11750-017-0464-1

Date of publication: 2018-04

Abstract:

Multinomial values were previously introduced by one of the authors in reliability and extended later to all cooperative games. Here, we present for this subfamily of probabilistic values three new results, previously stated only for binomial semivalues in the literature. They concern the dimension of the subspace spanned by the multinomial values and two characterizations: one, individual, for each multinomial value; another, collective, for the whole subfamily they form. Finally, an application to simple games is provided

This is a post-peer-review, pre-copyedit version of an article published in "TOP". The final authenticated version is available online at: https://doi.org/10.1007/s11750-017-0464-1]]>

Abstract:

In this thesis we analyse the problems of evaluating the power of players in different voting situations and of creating a ranking among them. We start our analysis in the classical set of cooperative game theory. We present a theorem to characterize the family of semivalues, a class of solution concepts, by means of their behaviour on unanimity games and to establish a connection between semivalues and completely monotonic sequences. Then, we provide a new formula to compute the Shapley value due to a different interpretation of the value that is particularly meaningful in the voting context. Secondly, we examine the model of games with abstention. We introduce some properties for the indices for games with abstention and generalize to this set some of the properties that have been provided in literature to characterize the corresponding power indices for simple games. We use these results to provide two different axiomatizations for the Banzhaf index for games with abstention and a characterization of the Shapley-Shubik index for games with abstention. We then focus on multichoice cooperative games, an extension of the classical model of cooperative games, to describe situations in which players can have different levels of participation in the cooperation (or they have to vote among different alternatives). We analyse and compare the different models studied in literature and we define a new value for multichoice cooperative games in the spirit of the Shapley value. As a consequence of our result, we provide an explicit formula to compute the Shapley-Shubik index for games with abstention. In the last part of the thesis, we consider the problem of ranking players from a new perspective: we remove the structure of coalitional game and suppose that only an ordinal ranking among players is available. We present two functions that associate a ranking over the players, given a preference profile over the subsets formed by those players. We also provide an axiomatic characterization of these two functions by means of a set of axioms we introduce and discuss.]]>

Optimization

Vol. 67, num. 6, p. 907-919

DOI: 10.1080/02331934.2018.1432611

Date of publication: 2018-02-04

Abstract:

We introduce bisemivalues for bicooperative games and we also provide an interesting characterization of this kind of values by means of weighting coefficients in a similar way as it was given for semivalues in the context of cooperative games. Moreover, the notion of induced bisemivalues on lower cardinalities also makes sense and an adaptation of Dragan’s recurrence formula is obtained. For the particular case of (p, q)-bisemivalues, a computational procedure in terms of the multilinear extension of the game is given.]]>