Reports de recerca
http://hdl.handle.net/2117/3973
Thu, 26 May 2016 12:54:04 GMT2016-05-26T12:54:04ZA review on multi-agent platforms and environmental decision support systems simulation tools
http://hdl.handle.net/2117/87344
A review on multi-agent platforms and environmental decision support systems simulation tools
Rendón Sallard, Thania; Sánchez Marrè, Miquel
This work depicts the state of the art of Multi-agent systems platforms for the development of Multi-agent systems, and reviews the Environmental Decision Support Systems Simulation tools available.
Thu, 26 May 2016 08:23:14 GMThttp://hdl.handle.net/2117/873442016-05-26T08:23:14ZRendón Sallard, ThaniaSánchez Marrè, MiquelThis work depicts the state of the art of Multi-agent systems platforms for the development of Multi-agent systems, and reviews the Environmental Decision Support Systems Simulation tools available.A review on DISC 2005, the 19th International Symposium on Distributed Computing
http://hdl.handle.net/2117/87343
A review on DISC 2005, the 19th International Symposium on Distributed Computing
Blesa Aguilera, Maria Josep; Georgiou, Chryssis
DISC is an international symposium on the theory, design, analysis, implementation and application of distributed systems and networks. The well-known International Symposium on Distributed Computing is organized annually in cooperation with the European Association for Theoretical Computer Science (EATCS). This is a review on the 19th International Symposium on Distributed Computing, which took place in Kraków, Poland, on September 26--29, 2005. The proceedings of DISC 2005 are published by Springer, as volume 3724 of the Lecture Notes in Computer Science (LNCS) series. The conference website can be found at www.mimuw.edu.pl/~disc2005.
Thu, 26 May 2016 08:10:28 GMThttp://hdl.handle.net/2117/873432016-05-26T08:10:28ZBlesa Aguilera, Maria JosepGeorgiou, ChryssisDISC is an international symposium on the theory, design, analysis, implementation and application of distributed systems and networks. The well-known International Symposium on Distributed Computing is organized annually in cooperation with the European Association for Theoretical Computer Science (EATCS). This is a review on the 19th International Symposium on Distributed Computing, which took place in Kraków, Poland, on September 26--29, 2005. The proceedings of DISC 2005 are published by Springer, as volume 3724 of the Lecture Notes in Computer Science (LNCS) series. The conference website can be found at www.mimuw.edu.pl/~disc2005.An implementation of a generic memetic algorithm for the edge biconnectivity augmentation problem
http://hdl.handle.net/2117/87262
An implementation of a generic memetic algorithm for the edge biconnectivity augmentation problem
Xhafa Xhafa, Fatos
In this paper we present an implementation of a generic memetic algorithm for the edge bi-connectivity augmentation problem --the problem of augmenting a given graph by a cheapest possible set of additional edges in order to make the graph edge bi-connected. This problem is known for its applications to communication network design --the extension of an existing communication network to become robust against single link failures-- as well as in VLSI floor planning. We provide a C++ implementation of a generic memetic algorithm for the problem, as a good alternative for approximately solving it. We use known benchmarks in the literature for the problem as to experimentally evaluate how good the generic memetic algorithm works for the problem.
Tue, 24 May 2016 09:08:56 GMThttp://hdl.handle.net/2117/872622016-05-24T09:08:56ZXhafa Xhafa, FatosIn this paper we present an implementation of a generic memetic algorithm for the edge bi-connectivity augmentation problem --the problem of augmenting a given graph by a cheapest possible set of additional edges in order to make the graph edge bi-connected. This problem is known for its applications to communication network design --the extension of an existing communication network to become robust against single link failures-- as well as in VLSI floor planning. We provide a C++ implementation of a generic memetic algorithm for the problem, as a good alternative for approximately solving it. We use known benchmarks in the literature for the problem as to experimentally evaluate how good the generic memetic algorithm works for the problem.A methodology to develop answers to definitional questions
http://hdl.handle.net/2117/87258
A methodology to develop answers to definitional questions
Kanaan Izquierdo, Samir
This report tries to give a general vision of the state of art of the task of definitional question answering, by describing the task, illustrating the current interest on it, pointing out its main evaluation methods and the competitions that include subtasks of definitional question answering. The generical architecture of definitional question answering systems is presented, along with a description of the main techniques applied in the resolution of this problem. Finally, most important results in the task are presented and the main conclusions are exposed.
Tue, 24 May 2016 08:17:43 GMThttp://hdl.handle.net/2117/872582016-05-24T08:17:43ZKanaan Izquierdo, SamirThis report tries to give a general vision of the state of art of the task of definitional question answering, by describing the task, illustrating the current interest on it, pointing out its main evaluation methods and the competitions that include subtasks of definitional question answering. The generical architecture of definitional question answering systems is presented, along with a description of the main techniques applied in the resolution of this problem. Finally, most important results in the task are presented and the main conclusions are exposed.Estado del arte de la alineación de imágenes médicas e implementación del algoritmo de alineación clásico basado en la información mutua
http://hdl.handle.net/2117/87257
Estado del arte de la alineación de imágenes médicas e implementación del algoritmo de alineación clásico basado en la información mutua
Murillo Pavas, Santiago; Navazo Álvaro, Isabel; Vinacua Pla, Álvaro
La alineación de imágenes cardíacas procedentes de imágenes de medicina nuclear tal como la Tomografía Computerizada por Emisión Única de Positrones (SPECT) constituye un campo de investigación activo dada su importancia en el diagnóstico de cardiopatías. En este reporte presentamos el estado del arte de la alineación de imágenes médicas con énfasis en la alineación de imágenes cardíacas al igual que una aplicación del método de alineación para imágenes SPECT cardíacos usando la información mutua como medida de similitud.; Cardiac images registration coming from nuclear medicine like Single Positron
Emition Computer Tomography (SPECT) has become an active research field since it is an important tool for the diagnostic of cardiac pathologies. In this report we present the state of the art of medical image registration with emphasis in cardiac images, likewise it is presented an application for registration of SPECT images using mutual information like similarity measure.
Tue, 24 May 2016 07:42:22 GMThttp://hdl.handle.net/2117/872572016-05-24T07:42:22ZMurillo Pavas, SantiagoNavazo Álvaro, IsabelVinacua Pla, ÁlvaroLa alineación de imágenes cardíacas procedentes de imágenes de medicina nuclear tal como la Tomografía Computerizada por Emisión Única de Positrones (SPECT) constituye un campo de investigación activo dada su importancia en el diagnóstico de cardiopatías. En este reporte presentamos el estado del arte de la alineación de imágenes médicas con énfasis en la alineación de imágenes cardíacas al igual que una aplicación del método de alineación para imágenes SPECT cardíacos usando la información mutua como medida de similitud.
Cardiac images registration coming from nuclear medicine like Single Positron
Emition Computer Tomography (SPECT) has become an active research field since it is an important tool for the diagnostic of cardiac pathologies. In this report we present the state of the art of medical image registration with emphasis in cardiac images, likewise it is presented an application for registration of SPECT images using mutual information like similarity measure.Geometric objects in Blender 2.32
http://hdl.handle.net/2117/87256
Geometric objects in Blender 2.32
Vigo Anglada, Marc
The aim of this document is to explore the way that Blender 2.32 stores the information for modeling static scenes. First, the conceptual model the system uses to store geometric objects is explained, guiding the user to inspect it using the OOPS Schematic view. The data structures Blender uses for generic objects, geometric elements, materials and different kind of links between these entities are reviewed. Special emphasis is made for the case of meshes, and the main features of the mesh editor are enumerated. Finally, a collection of exercices for the user is suggested, with the aim that he/she enforces these concepts.
Tue, 24 May 2016 07:17:00 GMThttp://hdl.handle.net/2117/872562016-05-24T07:17:00ZVigo Anglada, MarcThe aim of this document is to explore the way that Blender 2.32 stores the information for modeling static scenes. First, the conceptual model the system uses to store geometric objects is explained, guiding the user to inspect it using the OOPS Schematic view. The data structures Blender uses for generic objects, geometric elements, materials and different kind of links between these entities are reviewed. Special emphasis is made for the case of meshes, and the main features of the mesh editor are enumerated. Finally, a collection of exercices for the user is suggested, with the aim that he/she enforces these concepts.An algebraic view of the relation between largest common subtrees and smallest common supertrees
http://hdl.handle.net/2117/87254
An algebraic view of the relation between largest common subtrees and smallest common supertrees
Rosselló, Francesc; Valiente Feruglio, Gabriel Alejandro
The relationship between two important problems in tree pattern matching, the largest common subtree and the smallest common supertree of two trees, is established by means of simple constructions, which allow one to obtain the largest common subtree from the smallest common supertree, and vice versa. These constructions are given for the problems of isomorphic, homeomorphic, topological, and minor embeddings. They can be implemented by a straightforward extension of any algorithm that solves one of the two problems, and the extension only takes time linear in the size of the trees.
Tue, 24 May 2016 07:04:02 GMThttp://hdl.handle.net/2117/872542016-05-24T07:04:02ZRosselló, FrancescValiente Feruglio, Gabriel AlejandroThe relationship between two important problems in tree pattern matching, the largest common subtree and the smallest common supertree of two trees, is established by means of simple constructions, which allow one to obtain the largest common subtree from the smallest common supertree, and vice versa. These constructions are given for the problems of isomorphic, homeomorphic, topological, and minor embeddings. They can be implemented by a straightforward extension of any algorithm that solves one of the two problems, and the extension only takes time linear in the size of the trees.An optimal anytime estimation algorithm
http://hdl.handle.net/2117/87244
An optimal anytime estimation algorithm
Gavaldà Mestre, Ricard
In many applications a key step is estimating some unknown quantity ~$mu$ from a sequence of trials, each having expected value~$mu$. Optimal algorithms are known when the task is to estimate $mu$ within a multiplicative factor of $epsilon$, for an $epsilon$ given in advance. In this paper we consider {em anytime} approximation algorithms, i.e., algorithms that must give a reliable approximation after each trial, and whose approximations have to be increasingly accurate as the number of trials grows. We give an anytime algorithm for this task when the only a-priori known property of $mu$ is its range, and show that it is asymptotically optimal in some cases, in the sense that no correct anytime algorithm can give asymptotically better approximations. The key ingredient is a new large deviation bound for the supremum of the deviations in an infinite sequence of trials, which can be seen as a non-limit analog of the classical Law of the Iterated Logarithm.
Mon, 23 May 2016 14:19:52 GMThttp://hdl.handle.net/2117/872442016-05-23T14:19:52ZGavaldà Mestre, RicardIn many applications a key step is estimating some unknown quantity ~$mu$ from a sequence of trials, each having expected value~$mu$. Optimal algorithms are known when the task is to estimate $mu$ within a multiplicative factor of $epsilon$, for an $epsilon$ given in advance. In this paper we consider {em anytime} approximation algorithms, i.e., algorithms that must give a reliable approximation after each trial, and whose approximations have to be increasingly accurate as the number of trials grows. We give an anytime algorithm for this task when the only a-priori known property of $mu$ is its range, and show that it is asymptotically optimal in some cases, in the sense that no correct anytime algorithm can give asymptotically better approximations. The key ingredient is a new large deviation bound for the supremum of the deviations in an infinite sequence of trials, which can be seen as a non-limit analog of the classical Law of the Iterated Logarithm.Continuous monitoring in the dynamic sensor field model
http://hdl.handle.net/2117/87176
Continuous monitoring in the dynamic sensor field model
Álvarez Faura, M. del Carme; Díaz Cort, Josep; Dieter Wilhelm, Mitsche; Serna Iglesias, María José
In this work we consider the problem of continuously monitoring a collection of data sets produced by sensors placed on moving or static targets. We propose a modification of the static sensor field model (SSSF) [2] to model computation in a dynamic network of tiny artifacts. We consider mobility coming from both the communication devices and the data. The mobility of devices is simulated by a dynamic communication graph. Data mobility is due to measurements performed by sensing devices that are not placed on fixed positions but attached to mobile agents. Accordingly, we introduce additional performance measures: the traveled distance and the gathering period. We study the Continuous Monitoring problem providing bounds on performance for algorithms that use mobility in different ways.
Thu, 19 May 2016 08:43:29 GMThttp://hdl.handle.net/2117/871762016-05-19T08:43:29ZÁlvarez Faura, M. del CarmeDíaz Cort, JosepDieter Wilhelm, MitscheSerna Iglesias, María JoséIn this work we consider the problem of continuously monitoring a collection of data sets produced by sensors placed on moving or static targets. We propose a modification of the static sensor field model (SSSF) [2] to model computation in a dynamic network of tiny artifacts. We consider mobility coming from both the communication devices and the data. The mobility of devices is simulated by a dynamic communication graph. Data mobility is due to measurements performed by sensing devices that are not placed on fixed positions but attached to mobile agents. Accordingly, we introduce additional performance measures: the traveled distance and the gathering period. We study the Continuous Monitoring problem providing bounds on performance for algorithms that use mobility in different ways.Rank selection in multidimensional data
http://hdl.handle.net/2117/87150
Rank selection in multidimensional data
Duch Brown, Amalia; Jiménez Gómez, Rosa María; Martínez Parra, Conrado
Suppose we have a set of K-dimensional records stored in a general purpose spatial index like a K-d tree. The index efficiently supports insertions, ordinary exact searches, orthogonal range searches, nearest neighbor searches, etc. Here we consider whether we can also efficiently support search by rank, that is, to locate the i-th smallest element along the j-th coordinate. We answer this question in the affirmative by developing a simple algorithm with expected cost O(na(1/K) log n), where n is the size of the K-d tree and a(1/K) < 1 for any K ¿ 2. The only requirement to support the search by rank is that each node in the K-d tree stores the size of the subtree rooted at that node (or some equivalent information). This is not too space demanding. Furthermore, it can be used to randomize the update algorithms to provide guarantees on the expected performance of the various operations on K-d trees. Although selection in multidimensional data can be solved more efficiently than with our algorithm, those solutions will rely on ad-hoc data structures or superlinear space. Our solution adds to an existing data structure (K-d trees) the capability of search by rank with very little overhead. The simplicity of the algorithm makes it easy to implement, practical and very flexible; however, its correctness and efficiency are far from self-evident. Furthermore, it can be easily adapted to other spatial indexes as well.
Wed, 18 May 2016 08:32:10 GMThttp://hdl.handle.net/2117/871502016-05-18T08:32:10ZDuch Brown, AmaliaJiménez Gómez, Rosa MaríaMartínez Parra, ConradoSuppose we have a set of K-dimensional records stored in a general purpose spatial index like a K-d tree. The index efficiently supports insertions, ordinary exact searches, orthogonal range searches, nearest neighbor searches, etc. Here we consider whether we can also efficiently support search by rank, that is, to locate the i-th smallest element along the j-th coordinate. We answer this question in the affirmative by developing a simple algorithm with expected cost O(na(1/K) log n), where n is the size of the K-d tree and a(1/K) < 1 for any K ¿ 2. The only requirement to support the search by rank is that each node in the K-d tree stores the size of the subtree rooted at that node (or some equivalent information). This is not too space demanding. Furthermore, it can be used to randomize the update algorithms to provide guarantees on the expected performance of the various operations on K-d trees. Although selection in multidimensional data can be solved more efficiently than with our algorithm, those solutions will rely on ad-hoc data structures or superlinear space. Our solution adds to an existing data structure (K-d trees) the capability of search by rank with very little overhead. The simplicity of the algorithm makes it easy to implement, practical and very flexible; however, its correctness and efficiency are far from self-evident. Furthermore, it can be easily adapted to other spatial indexes as well.