Articles de revista
http://hdl.handle.net/2117/3430
Sun, 12 Jul 2020 04:38:45 GMT
20200712T04:38:45Z

Exponential decay in onedimensional Type II/III thermoelasticity with two porosities
http://hdl.handle.net/2117/187178
Exponential decay in onedimensional Type II/III thermoelasticity with two porosities
Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
In this paper we consider the theory of thermoelasticity with a double porosity structure in the context of the GreenNaghdi types II and III heat conduction models. For the type II, the problem is given by four hyperbolic equations and it is conservative (there is no energy dissipation). We introduce in the system a couple of dissipation mechanisms in order to obtain the exponential de cay of the solutions. To be precise, we introduce a pair of the following damping mechanisms: viscoelasticity, viscoporosities and thermal dissipation. We prove that the system is exponentially stable in three different scenarios: viscoporosity in one structure jointly with thermal dissipation, viscoporosity in each structure, and viscoporosity in one structure jointly with viscoelasticity. However, if viscoelasticity and thermal dissipation are considered together, undamped solutions can be obtained.
Tue, 12 May 2020 07:21:27 GMT
http://hdl.handle.net/2117/187178
20200512T07:21:27Z
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
In this paper we consider the theory of thermoelasticity with a double porosity structure in the context of the GreenNaghdi types II and III heat conduction models. For the type II, the problem is given by four hyperbolic equations and it is conservative (there is no energy dissipation). We introduce in the system a couple of dissipation mechanisms in order to obtain the exponential de cay of the solutions. To be precise, we introduce a pair of the following damping mechanisms: viscoelasticity, viscoporosities and thermal dissipation. We prove that the system is exponentially stable in three different scenarios: viscoporosity in one structure jointly with thermal dissipation, viscoporosity in each structure, and viscoporosity in one structure jointly with viscoelasticity. However, if viscoelasticity and thermal dissipation are considered together, undamped solutions can be obtained.

Some properties for bisemivalues on bicooperative games
http://hdl.handle.net/2117/185232
Some properties for bisemivalues on bicooperative games
Domènech Blázquez, Margarita; Giménez Pradales, José Miguel; Puente del Campo, María Albina
In this work, we focus on bicooperative games, a variation of the classic cooperative games, and investigate the conditions for the coefficients of the bisemivalues—a generalization of semivalues for cooperative games—necessary and / or sufficient in order to satisfy some properties, including among others, desirability relation, balanced contributions, null player exclusion property and block property. Moreover, a computational procedure to calculate bisemivalues in terms of the multilinear extension of the game is given.
This is a postpeerreview, precopyedit version of an article published in Journal of Optimization Theory and Applications. The final authenticated version is available online at: http://dx.doi.org/10.1007%2Fs1095702001640x.
Mon, 27 Apr 2020 10:41:47 GMT
http://hdl.handle.net/2117/185232
20200427T10:41:47Z
Domènech Blázquez, Margarita
Giménez Pradales, José Miguel
Puente del Campo, María Albina
In this work, we focus on bicooperative games, a variation of the classic cooperative games, and investigate the conditions for the coefficients of the bisemivalues—a generalization of semivalues for cooperative games—necessary and / or sufficient in order to satisfy some properties, including among others, desirability relation, balanced contributions, null player exclusion property and block property. Moreover, a computational procedure to calculate bisemivalues in terms of the multilinear extension of the game is given.

The Banzhaf value for cooperative and simple multichoice games
http://hdl.handle.net/2117/175430
The Banzhaf value for cooperative and simple multichoice games
Freixas Bosch, Josep
This article proposes a value which can be considered an extension of the Banzhaf value for cooperative games. The proposed value is defined on the class of jcooperative games, i.e., games in which players choose among a finite set of ordered actions and the result depends only on these elections. If the output is binary, only two options are available, then jcooperative games become jsimple games. The restriction of the value to jsimple games leads to a power index that can be considered an extension of the Banzhaf power index for simple games. The paper provides an axiomatic characterization for the value and the index which is closely related to the first axiomatization of the Banzhaf value and Banzhaf power index in the respective contexts of cooperative and simple games.
This is a postpeerreview, precopyedit version of an article published in Group Decision and Negotiation. The final authenticated version is available online at: https://doi.org/10.1007/s10726019096514.
Wed, 22 Jan 2020 12:23:36 GMT
http://hdl.handle.net/2117/175430
20200122T12:23:36Z
Freixas Bosch, Josep
This article proposes a value which can be considered an extension of the Banzhaf value for cooperative games. The proposed value is defined on the class of jcooperative games, i.e., games in which players choose among a finite set of ordered actions and the result depends only on these elections. If the output is binary, only two options are available, then jcooperative games become jsimple games. The restriction of the value to jsimple games leads to a power index that can be considered an extension of the Banzhaf power index for simple games. The paper provides an axiomatic characterization for the value and the index which is closely related to the first axiomatization of the Banzhaf value and Banzhaf power index in the respective contexts of cooperative and simple games.

Numerical analysis of a dualphaselag model involving two temperatures
http://hdl.handle.net/2117/175293
Numerical analysis of a dualphaselag model involving two temperatures
Bazarra, Noelia; Fernández, José Ramón; Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
In this paper, we numerically analyse a phaselag model with two temperatures which arises in the heat conduction theory. The model is written as a linear partial differential equation of third order in time. The variational formulation, written in terms of the thermal acceleration, leads to a linear variational equation, for which we recall an existence and uniqueness result and an energy decay property. Then, using the finite element method to approximate the spatial variable and the implicit Euler scheme to discretize the time derivatives, fully discrete approximations are introduced. A discrete stability property is proved, and a priori error estimates are obtained, from which the linear convergence of the approximation is derived. Finally, some onedimensional numerical simulations are described to demonstrate the accuracy of the approximation and the behaviour of the solution.
Mon, 20 Jan 2020 13:43:55 GMT
http://hdl.handle.net/2117/175293
20200120T13:43:55Z
Bazarra, Noelia
Fernández, José Ramón
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
In this paper, we numerically analyse a phaselag model with two temperatures which arises in the heat conduction theory. The model is written as a linear partial differential equation of third order in time. The variational formulation, written in terms of the thermal acceleration, leads to a linear variational equation, for which we recall an existence and uniqueness result and an energy decay property. Then, using the finite element method to approximate the spatial variable and the implicit Euler scheme to discretize the time derivatives, fully discrete approximations are introduced. A discrete stability property is proved, and a priori error estimates are obtained, from which the linear convergence of the approximation is derived. Finally, some onedimensional numerical simulations are described to demonstrate the accuracy of the approximation and the behaviour of the solution.

A problem with viscoelastic mixtures: numerical analysis and computational experiments
http://hdl.handle.net/2117/173986
A problem with viscoelastic mixtures: numerical analysis and computational experiments
Fernández, José Ramón; Masid, Maria; Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
In this paper, we study, from the numerical point of view, a dynamic problem involving a mixture of two viscoelastic solids. The mechanical problem is written as a system of two coupled partial differential equations. Its variational formulation is derived and an existence and uniqueness result, and an energy decay property, are recalled. Then, fully discrete approximations are introduced by using the classical finite element method and the implicit Euler scheme. A discrete stability property and a priori error estimates are shown, from which we deduce the linear convergence of the algorithm. Finally, some numerical simulations, including examples in one and two dimensions, are presented to show the accuracy of the approximation and the behaviour of the solution.
Mon, 16 Dec 2019 13:16:02 GMT
http://hdl.handle.net/2117/173986
20191216T13:16:02Z
Fernández, José Ramón
Masid, Maria
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
In this paper, we study, from the numerical point of view, a dynamic problem involving a mixture of two viscoelastic solids. The mechanical problem is written as a system of two coupled partial differential equations. Its variational formulation is derived and an existence and uniqueness result, and an energy decay property, are recalled. Then, fully discrete approximations are introduced by using the classical finite element method and the implicit Euler scheme. A discrete stability property and a priori error estimates are shown, from which we deduce the linear convergence of the algorithm. Finally, some numerical simulations, including examples in one and two dimensions, are presented to show the accuracy of the approximation and the behaviour of the solution.

On the linear thermoelasticity with two porosities: numerical aspects
http://hdl.handle.net/2117/171631
On the linear thermoelasticity with two porosities: numerical aspects
Bazarra, Noelia; Fernández, José Ramón; Leseduarte Milán, María Carme; Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
In this work we analyze, from the numerical point of view, a dynamic problem involving a thermoelastic rod. Two porosities are considered: the first one is the macroporosity, connected with the pores of the material, and the other one is the microporosity, linked with the fissures of the skeleton. The mechanical problem is written as a set of hyperbolic and parabolic partial differential equations. An existence and uniqueness result and an energy decay property are stated. Then, a fully discrete approximation is introduced using the finite element method and the backward Euler scheme. A discrete stability property and a priori error estimates are proved, from which the linear convergence of the algorithm is derived under suitable additional regularity conditions. Finally, some numerical simulations are presented to show the behaviour of the approximation
Tue, 05 Nov 2019 08:19:09 GMT
http://hdl.handle.net/2117/171631
20191105T08:19:09Z
Bazarra, Noelia
Fernández, José Ramón
Leseduarte Milán, María Carme
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
In this work we analyze, from the numerical point of view, a dynamic problem involving a thermoelastic rod. Two porosities are considered: the first one is the macroporosity, connected with the pores of the material, and the other one is the microporosity, linked with the fissures of the skeleton. The mechanical problem is written as a set of hyperbolic and parabolic partial differential equations. An existence and uniqueness result and an energy decay property are stated. Then, a fully discrete approximation is introduced using the finite element method and the backward Euler scheme. A discrete stability property and a priori error estimates are proved, from which the linear convergence of the algorithm is derived under suitable additional regularity conditions. Finally, some numerical simulations are presented to show the behaviour of the approximation

On the time decay in phaselag thermoelasticity with two temperatures
http://hdl.handle.net/2117/170281
On the time decay in phaselag thermoelasticity with two temperatures
Magaña Nieto, Antonio; Miranville, Alain; Quintanilla de Latorre, Ramón
The aim of this paper is to study the time decay of the solutions for two models of the onedimensional phaselag thermoelasticity with two temperatures. The first one is obtained when the heat flux vector and the inductive temperature are approximated by a secondorder and firstorder Taylor polynomial, respectively. In this case, the solutions decay in a slow way. The second model that we consider is obtained taking
firstorder Taylor approximations for the inductive thermal displacement, the inductive temperature and the heat flux. The decay is, therefore, of exponential type.
Wed, 16 Oct 2019 15:51:40 GMT
http://hdl.handle.net/2117/170281
20191016T15:51:40Z
Magaña Nieto, Antonio
Miranville, Alain
Quintanilla de Latorre, Ramón
The aim of this paper is to study the time decay of the solutions for two models of the onedimensional phaselag thermoelasticity with two temperatures. The first one is obtained when the heat flux vector and the inductive temperature are approximated by a secondorder and firstorder Taylor polynomial, respectively. In this case, the solutions decay in a slow way. The second model that we consider is obtained taking
firstorder Taylor approximations for the inductive thermal displacement, the inductive temperature and the heat flux. The decay is, therefore, of exponential type.

Exponential stability in threedimensional type III thermoporouselasticity with microtemperatures
http://hdl.handle.net/2117/170099
Exponential stability in threedimensional type III thermoporouselasticity with microtemperatures
Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
We study the time decay of the solutions for the type III thermoelastic theory with microtemperatures and voids. We prove that, under suitable conditions for the constitutive tensors, the solutions decay exponentially. This fact is in somehow striking because it differs from the behaviour of the solutions in the classical model of thermoelasticity with microtemperatures and voids, where the exponential decay is not expected in the general case.
Tue, 15 Oct 2019 09:59:10 GMT
http://hdl.handle.net/2117/170099
20191015T09:59:10Z
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
We study the time decay of the solutions for the type III thermoelastic theory with microtemperatures and voids. We prove that, under suitable conditions for the constitutive tensors, the solutions decay exponentially. This fact is in somehow striking because it differs from the behaviour of the solutions in the classical model of thermoelasticity with microtemperatures and voids, where the exponential decay is not expected in the general case.

The neighborhood role in the linear threshold rank on social networks
http://hdl.handle.net/2117/169655
The neighborhood role in the linear threshold rank on social networks
Riquelme Csori, Fabián; Gonzalez Cantergiani, Pablo; Molinero Albareda, Xavier; Serna Iglesias, María José
Centrality and influence spread are two of the most studied concepts in social network analysis. Several centrality measures, most of them, based on topological criteria, have been proposed and studied. In recent years new centrality measures have been defined inspired by the two main influence spread models, namely, the Independent Cascade Model (ICmodel) and the Linear Threshold Model (LTmodel). The Linear Threshold Rank (LTR) is defined as the total number of influenced nodes when the initial activation set is formed by a node and its immediate neighbors. It has been shown that LTR allows to rank influential actors in a more distinguishable way than other measures like the PageRank, the Katz centrality, or the Independent Cascade Rank. In this paper we propose a generalized LTR measure that explore the sensitivity of the original LTR, with respect to the distance of the neighbors included in the initial activation set. We appraise the viability of the approach through different case studies. Our results show that by using neighbors at larger distance, we obtain rankings that distinguish better the influential actors. However, the best differentiating ranks correspond to medium distances. Our experiments also show that the rankings obtained for the different levels of neighborhood are not highly correlated, which validates the measure generalization
Thu, 10 Oct 2019 11:30:23 GMT
http://hdl.handle.net/2117/169655
20191010T11:30:23Z
Riquelme Csori, Fabián
Gonzalez Cantergiani, Pablo
Molinero Albareda, Xavier
Serna Iglesias, María José
Centrality and influence spread are two of the most studied concepts in social network analysis. Several centrality measures, most of them, based on topological criteria, have been proposed and studied. In recent years new centrality measures have been defined inspired by the two main influence spread models, namely, the Independent Cascade Model (ICmodel) and the Linear Threshold Model (LTmodel). The Linear Threshold Rank (LTR) is defined as the total number of influenced nodes when the initial activation set is formed by a node and its immediate neighbors. It has been shown that LTR allows to rank influential actors in a more distinguishable way than other measures like the PageRank, the Katz centrality, or the Independent Cascade Rank. In this paper we propose a generalized LTR measure that explore the sensitivity of the original LTR, with respect to the distance of the neighbors included in the initial activation set. We appraise the viability of the approach through different case studies. Our results show that by using neighbors at larger distance, we obtain rankings that distinguish better the influential actors. However, the best differentiating ranks correspond to medium distances. Our experiments also show that the rankings obtained for the different levels of neighborhood are not highly correlated, which validates the measure generalization

An axiomatization for two power indices for (3,2)simple games
http://hdl.handle.net/2117/133317
An axiomatization for two power indices for (3,2)simple games
Bernardi, Giulia; Freixas Bosch, Josep
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. 124. DOI: 10.1142/S0219198919400012] © World Scientific Publishing Company https://www.worldscientific.com/doi/10.1142/S0219198919400012
Wed, 22 May 2019 08:45:25 GMT
http://hdl.handle.net/2117/133317
20190522T08:45:25Z
Bernardi, Giulia
Freixas Bosch, Josep
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.