Articles de revista
http://hdl.handle.net/2117/3430
2019-10-20T12:28:19Z
2019-10-20T12:28:19Z
On the time decay in phase-lag thermoelasticity with two temperatures
Magaña Nieto, Antonio
Miranville, Alain
Quintanilla de Latorre, Ramón
http://hdl.handle.net/2117/170281
2019-10-17T05:20:42Z
2019-10-16T15:51:40Z
On the time decay in phase-lag 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 one-dimensional phase-lag thermoelasticity with two temperatures. The first one is obtained when the heat flux vector and the inductive temperature are approximated by a second-order and first-order Taylor polynomial, respectively. In this case, the solutions decay in a slow way. The second model that we consider is obtained taking
first-order Taylor approximations for the inductive thermal displacement, the inductive temperature and the heat flux. The decay is, therefore, of exponential type.
2019-10-16T15:51:40Z
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 one-dimensional phase-lag thermoelasticity with two temperatures. The first one is obtained when the heat flux vector and the inductive temperature are approximated by a second-order and first-order Taylor polynomial, respectively. In this case, the solutions decay in a slow way. The second model that we consider is obtained taking
first-order Taylor approximations for the inductive thermal displacement, the inductive temperature and the heat flux. The decay is, therefore, of exponential type.
Exponential stability in three-dimensional type III thermo-porous-elasticity with microtemperatures
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
http://hdl.handle.net/2117/170099
2019-10-16T06:20:16Z
2019-10-15T09:59:10Z
Exponential stability in three-dimensional type III thermo-porous-elasticity 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.
2019-10-15T09:59:10Z
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
Riquelme Csori, Fabián
Gonzalez Cantergiani, Pablo
Molinero Albareda, Xavier
Serna Iglesias, María José
http://hdl.handle.net/2117/169655
2019-10-11T06:01:54Z
2019-10-10T11:30:23Z
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 (IC-model) and the Linear Threshold Model (LT-model). 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
2019-10-10T11:30:23Z
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 (IC-model) and the Linear Threshold Model (LT-model). 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
Benardi, Giulia
Freixas Bosch, Josep
http://hdl.handle.net/2117/133317
2019-05-23T03:10:13Z
2019-05-22T08:45:25Z
An axiomatization for two power indices for (3,2)-simple games
Benardi, 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. 1-24. DOI: 10.1142/S0219198919400012] © World Scientific Publishing Company https://www-worldscientific-com.recursos.biblioteca.upc.edu/doi/abs/10.1142/S0219198919400012
2019-05-22T08:45:25Z
Benardi, 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.
Measuring satisfaction and power in influence based decision systems
Molinero Albareda, Xavier
Riquelme Csori, Fabián
Serna Iglesias, María José
http://hdl.handle.net/2117/132016
2019-04-26T04:19:19Z
2019-04-25T11:46:03Z
Measuring satisfaction and power in influence based decision systems
Molinero Albareda, Xavier; Riquelme Csori, Fabián; Serna Iglesias, María José
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.
2019-04-25T11:46:03Z
Molinero Albareda, Xavier
Riquelme Csori, Fabián
Serna Iglesias, María José
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.
On the uniqueness and analyticity in viscoelasticity with double porosity
Bazarra, Noelia
Fernández, José Ramón
Leseduarte Milán, María Carme
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
http://hdl.handle.net/2117/131999
2019-04-26T04:19:14Z
2019-04-25T10:14:26Z
On the uniqueness and analyticity in viscoelasticity with double porosity
Bazarra, Noelia; Fernández, José Ramón; Leseduarte Milán, María Carme; Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
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.
2019-04-25T10:14:26Z
Bazarra, Noelia
Fernández, José Ramón
Leseduarte Milán, María Carme
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
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.
Bounds for the Nakamura number
Freixas Bosch, Josep
Kurz, Sascha
http://hdl.handle.net/2117/131906
2019-04-25T03:28:56Z
2019-04-24T10:22:40Z
Bounds for the Nakamura number
Freixas Bosch, Josep; Kurz, Sascha
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.
2019-04-24T10:22:40Z
Freixas Bosch, Josep
Kurz, Sascha
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.
Qualitative results for a mixture of Green-Lindsay thermoelastic solids
Magaña Nieto, Antonio
Muñoz Rivera, Jaime E.
Naso, Maria Grazia
Quintanilla de Latorre, Ramón
http://hdl.handle.net/2117/125861
2019-01-24T10:54:29Z
2018-12-17T12:35:05Z
Qualitative results for a mixture of Green-Lindsay thermoelastic solids
Magaña Nieto, Antonio; Muñoz Rivera, Jaime E.; Naso, Maria Grazia; Quintanilla de Latorre, Ramón
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
2018-12-17T12:35:05Z
Magaña Nieto, Antonio
Muñoz Rivera, Jaime E.
Naso, Maria Grazia
Quintanilla de Latorre, Ramón
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
A parameterization for a class of complete games with abstention
Freixas Bosch, Josep
Tchantcho, Bertrand
Proces Tsague, Bill
http://hdl.handle.net/2117/124189
2019-03-07T09:49:25Z
2018-11-14T08:52:16Z
A parameterization for a class of complete games with abstention
Freixas Bosch, Josep; Tchantcho, Bertrand; Proces Tsague, Bill
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.
2018-11-14T08:52:16Z
Freixas Bosch, Josep
Tchantcho, Bertrand
Proces Tsague, Bill
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.
Exponential stability in type III thermoelasticity with microtemperatures
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
http://hdl.handle.net/2117/122813
2019-01-24T10:53:54Z
2018-10-23T11:33:17Z
Exponential stability in type III thermoelasticity with microtemperatures
Magaña Nieto, Antonio; Quintanilla de Latorre, Ramón
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
2018-10-23T11:33:17Z
Magaña Nieto, Antonio
Quintanilla de Latorre, Ramón
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