
Jordán, Ramiro
Presentación del contenido del presente número.

Trojanowski, Krzysztof; Michalewicz, Zbigniew
As most realworld problemas are dynamic, it is not sufficient to "solve" the problem for the some (current) scenario, but it is also necessary to modify the current solution due to various changes in the environment (e. g., machine breakdowns, sickness of employees, etc.). Thus it is important to investigate properties of adaptive algorithms which do not require restart every time a change is recorded. In this paper such nonstationary problems (i. e., problems, which change in time) are considered. We describe different types of changes in the environment. A new model for nonstationary problems and a classifcation of these...

De Giusti, Armando Eduardo
In this book, Hansen presents a collection of structured multicomputer programs for computational science, with the unifying idea of programming paradigm.

De Giusti, Armando Eduardo
In this book, Hansen presents a collection of structured multicomputer programs for computational science, with the unifying idea of programming paradigm.

Rueda, Sonia Vivian
Agents repesent a new paradigm for developing software applications. In spite of the interest of this particular way of looking at problems, there is considerable discrepancy on exactly what is an agent and which are the attributes and properties that characterize them. The agentbased view offers not only a powerful repertoire of tools and techniques but also provides a powerfull metaphor that brings about a better conceptualization of the probelms in different areas of Computer Science. Many computational metaphors have become transparent. That fact has brought confusion to the use of some terms even at the velel of fundamental ideas....

Rueda, Sonia Vivian
Agents repesent a new paradigm for developing software applications. In spite of the interest of this particular way of looking at problems, there is considerable discrepancy on exactly what is an agent and which are the attributes and properties that characterize them. The agentbased view offers not only a powerful repertoire of tools and techniques but also provides a powerfull metaphor that brings about a better conceptualization of the probelms in different areas of Computer Science. Many computational metaphors have become transparent. That fact has brought confusion to the use of some terms even at the velel of fundamental ideas....

Cena, Marcelo Guillermo; Crespo, María Liz; Kavka, Carlos; Leguizamón, Mario Guillermo
This paper presents an Ant Colony Optimisation (ACO) model for the Multiple Knapsack Problem (MKP). The ACO algorithms, as well as other evolutionary metaphors, are being applied successfully to diverse heavily constrained problems: Travelling Salesman Problem, Quadratic Assignment Problem and Bin Packing Problem. An Ant System, the first ACO algorithm that we presented in this paper, is also considered a class of multiagent distributed algorithm for combinatorial optimisation. The principle of an ACO Algorithm is adapted to the MKP. We present some results regardin its perfomance against known optimun for different instances of MKP. The obtained results show the potential...

Cena, Marcelo Guillermo; Crespo, María Liz; Kavka, Carlos; Leguizamón, Mario Guillermo
This paper presents an Ant Colony Optimisation (ACO) model for the Multiple Knapsack Problem (MKP). The ACO algorithms, as well as other evolutionary metaphors, are being applied successfully to diverse heavily constrained problems: Travelling Salesman Problem, Quadratic Assignment Problem and Bin Packing Problem. An Ant System, the first ACO algorithm that we presented in this paper, is also considered a class of multiagent distributed algorithm for combinatorial optimisation. The principle of an ACO Algorithm is adapted to the MKP. We present some results regardin its perfomance against known optimun for different instances of MKP. The obtained results show the potential...

Cobo, María Laura; Augusto, Juan Carlos
The need of counting with the appropiate management of situations involving time an the motion of change, has been reconized as an important aspect in many Computer Science areas. This fact has made evident the need of tools to handle this kind of imformation. As a reflection of this relevance many temporal logic programming languages have been propose in the last few years. In particular, wel will present here a temporal logic programming called ETP. This language is based on the proposal prsented by Gabbay in (Gab87). The present article concerns the explanation of its logical foundations and the most...

Cobo, María Laura; Augusto, Juan Carlos
The need of counting with the appropiate management of situations involving time an the motion of change, has been reconized as an important aspect in many Computer Science areas. This fact has made evident the need of tools to handle this kind of imformation. As a reflection of this relevance many temporal logic programming languages have been propose in the last few years. In particular, wel will present here a temporal logic programming called ETP. This language is based on the proposal prsented by Gabbay in (Gab87). The present article concerns the explanation of its logical foundations and the most...

Lanzarini, Laura Cristina; Vargas Camacho, María Teresa; Flores Badrán, Amado; De Giusti, Armando Eduardo
Images compression is a widely studied topic. Conventional situations offer variable compression ratios depending on the image in question and, in general, do not yield good results for images that are rich in tones. This work is an application of images compression of patient s computed tomographies using neural networks, which allows to carry out both compression and decompression of the images with a fixed ratio of 8:1 and a loss of 2%.

Lanzarini, Laura Cristina; Vargas Camacho, María Teresa; Flores Badrán, Amado; De Giusti, Armando Eduardo
Images compression is a widely studied topic. Conventional situations offer variable compression ratios depending on the image in question and, in general, do not yield good results for images that are rich in tones. This work is an application of images compression of patient s computed tomographies using neural networks, which allows to carry out both compression and decompression of the images with a fixed ratio of 8:1 and a loss of 2%.

Lanzarini, Laura Cristina; Sanz, Cecilia Verónica; Naiouf, Marcelo; Romero, Fernando
Three alternatives within the method of assignment by classes are presented for the calculation of individuals lifetime in genetic algorithms with varying population size. (GAVaPS). In the proposed strategy (assignment by classes) individuals are grouped according to their fitness. The purpose is to use the allowed range of lifetime values in a way which is more suitable to search the optimum than proportional, linear and bilinear strategies. A comparative study of three possibilities of assignment by classes as related to the traditional methods is carried out, and results are shown over five functions. Finally, some conclusions are presented, along with...

Lanzarini, Laura Cristina; Sanz, Cecilia Verónica; Naiouf, Marcelo; Romero, Fernando
Three alternatives within the method of assignment by classes are presented for the calculation of individuals lifetime in genetic algorithms with varying population size. (GAVaPS). In the proposed strategy (assignment by classes) individuals are grouped according to their fitness. The purpose is to use the allowed range of lifetime values in a way which is more suitable to search the optimum than proportional, linear and bilinear strategies. A comparative study of three possibilities of assignment by classes as related to the traditional methods is carried out, and results are shown over five functions. Finally, some conclusions are presented, along with...

Falappa, Marcelo Alejandro; Fermé, Eduardo L.
In this article we will introduce certain considerations that must be taken into account while implementing the change operations of the belief change theory. The abstract models of bellief change make no considerations in respecto to the internal structures of the beliefs that compound the knowledge of an agent, and much less take into account the computational complexity of the proposed algorithms. In this article we will explicitly introduce some of the inconveniences and the possible solutions that can be found while implementing the change operations. Firstly, we will introduce the different change operations of the AGM model. These operations...

Falappa, Marcelo Alejandro; Fermé, Eduardo L.
In this article we will introduce certain considerations that must be taken into account while implementing the change operations of the belief change theory. The abstract models of bellief change make no considerations in respecto to the internal structures of the beliefs that compound the knowledge of an agent, and much less take into account the computational complexity of the proposed algorithms. In this article we will explicitly introduce some of the inconveniences and the possible solutions that can be found while implementing the change operations. Firstly, we will introduce the different change operations of the AGM model. These operations...

García, Alejandro Javier; Simari, Guillermo Ricardo
Implicitly exploitable parallelism for Logic Programming has received ample attention. Defeasible Argutmentation is specially apt for this optimizing technique. Defeasible Logic Programming (DLP), which is based on a defeasible argumentation formalism, could take full advantage of this type of parallel evaluation to improve the computational response of its proof procedure. In a defeasible argumentation formalism, a conclusion q is accepted only when the argument A that supports q becomes a justification. To decide if an argument A is a justification a dialectical analysis is performed. This analysis considers arguments and counterarguments. DLP extends conventional Logic Programming, capturing common sense reasoning...

García, Alejandro Javier; Simari, Guillermo Ricardo
Implicitly exploitable parallelism for Logic Programming has received ample attention. Defeasible Argutmentation is specially apt for this optimizing technique. Defeasible Logic Programming (DLP), which is based on a defeasible argumentation formalism, could take full advantage of this type of parallel evaluation to improve the computational response of its proof procedure. In a defeasible argumentation formalism, a conclusion q is accepted only when the argument A that supports q becomes a justification. To decide if an argument A is a justification a dialectical analysis is performed. This analysis considers arguments and counterarguments. DLP extends conventional Logic Programming, capturing common sense reasoning...

Riff Rojas, María Cristina
Our interest is to define evolutionary algorithms to solve Constraint Satisfaction Problems (CSP), which indlude benefits of taditional resolution methods of CSPs as well as inherent characteristics of these kind of problems. In this paper we propose a criterion to be able to evaluate the perfomance of genetic operators within evolutionary algorithms that solve CSp.

Riff Rojas, María Cristina
Our interest is to define evolutionary algorithms to solve Constraint Satisfaction Problems (CSP), which indlude benefits of taditional resolution methods of CSPs as well as inherent characteristics of these kind of problems. In this paper we propose a criterion to be able to evaluate the perfomance of genetic operators within evolutionary algorithms that solve CSp.