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Research paper thumbnail of Novel Models for Or-Parallel Logic Programs: A Performance Analysis

Lecture Notes in Computer Science, 2000

One of the advantages of logic programming is the fact that it offers many sources of implicit pa... more One of the advantages of logic programming is the fact that it offers many sources of implicit parallelism, such as and-parallelism and or-parallelism. Arguably, or-parallel systems, such as Aurora and Muse, have been the most successful parallel logic programming systems so far. Or-parallel systems rely on techniques such as Environment Copying to address the problem that branches being explored in parallel may need to assign different bindings for the same shared variable. Recent research has led to two new binding representation approaches that also support independent and-parallelism: the Sparse Binding Array and the Copy-On-Write binding models. In this paper, we investigate whether these newer models are practical alternatives to copying for or-parallelism. We based our work on YapOr, an or-parallel copying system using the YAP Prolog engine, so that the three alternative systems share schedulers and the underlying engine.

Research paper thumbnail of Achieving scalability in parallel tabled logic programs

Proceedings 16th International Parallel and Distributed Processing Symposium, 2002

Tabling or memoing is a technique where one stores intermediate answers to a problem so that they... more Tabling or memoing is a technique where one stores intermediate answers to a problem so that they can be reused in further calls. Tabling is of interest to logic programming because it addresses some of most significant weaknesses of Prolog. Namely, it can guarantee termination for programs with the bounded term-size property. Tabled programs exhibit a more complex execution mechanism than traditional Prolog's left-to-right search with backtracking. The reason is that Prolog programs are highly recursive and generate multiple answers. This rather involved execution mechanism requires a more complex implementation than traditional Prolog.

Research paper thumbnail of IMPACT: Innovative Models for Prolog with Advanced Control and Tabling

International Conference on Logic Programming/Joint International Conference and Symposium on Logic Programming, 2005

During the past years, our research group has been working in the design and implementation of Lo... more During the past years, our research group has been working in the design and implementation of Logic Programming Systems. In previous work, we have produced systems to support sequential, parallel and distributed execution of Prolog; to support novel techniques and models, such as tabling, through the YapTab system [1], or the Extended Andorra Model (EAM), through the BEAM [2]; and

Research paper thumbnail of Look what the cat dragged in: Felis silvestris catus as predators of insular bats and instance of predation on the endangered Pipistrellus maderensis

This note reports the predation of a threatened Madeira pipistrelle bat by a domestic house cat. ... more This note reports the predation of a threatened Madeira pipistrelle bat by a domestic house cat. This represents the first confirmed record of cat predation upon a Macaronesian bat and adds to an increasing body of evidence suggesting that free-ranging cats pose a strong negative impact to native insular vertebrate populations.

Research paper thumbnail of Birds in humanized landscapes: Sao Tomé endemic birds’ response to agricultural intensification

Research paper thumbnail of An Or-Parallel Prolog Execution Model for Clusters of Multicores

Research paper thumbnail of A Portable Prolog Predicate for Printing Rational Terms

Research paper thumbnail of A Parallel Virtual Machine for Executing Forward-Chaining Linear Logic Programs

Research paper thumbnail of A Simple and E cient Lock-Free Hash Trie Design for Concurrent Tabling

Research paper thumbnail of Design and Implementation of a Multithreaded Virtual Machine for Executing Linear Logic Programs

Research paper thumbnail of A Hybrid MapReduce Model for Prolog

Research paper thumbnail of Predation note: Anthus berthelotii madeirensis (Passeriformes: Motacillidae) catches Teira dugesii mauli (Squamata: Lacertidae) in Deserta Grande, Madeira Archipelago

Research paper thumbnail of EXTERNALIDADES DE PROYECTOS DE INFRAESTRUCTURA URBANA MEDICIÓN, VALORACION, INTERNALIZACION Y OPCIONES DE POLITICA EN AMERICA LATINA Y EL CARIBE: EL CASO DE METROVIVIENDA EN BOGOTÁ

Se describen los principales rasgos de las ciudadelas de MV en términos de características y meta... more Se describen los principales rasgos de las ciudadelas de MV en términos de características y metas, así como su esquema de gestión y resultados. Se contextualiza MV de acuerdo con el problema de la producción de suelo para la vivienda de interés social VIS, haciendo una reseña de los patrones de poblamiento de la ciudad y las condiciones de las localidades intervenidas por MV y las políticas de promoción de megaproyectos urbanos. Se analizan los costos y beneficios de MV para lo cual procede a realiza presentar una actualización de una evaluación pasada frente a la evolución reciente, se discuten sus alcance y limitaciones. A continuación, se hace una identificación de las externalidades de MV según sus componentes, las dimensiones urbanas del desarrollo sostenible, los atributos económicos de los bienes y los riesgos inherentes a la gestión. Se cualifica la correspondencia entre las externalidades y las políticas de urbanisticas de Bogota. Una focalización de la población de acuerdo a las externalidades identificadas y se realiza una discusión de las magnitudes conocidas.

Research paper thumbnail of Evidence of long-term stability in the iris pattern of Tarentola geckos

Research paper thumbnail of Felis silvestris catus como predador de murciélagos insulares y cita de depredación sobre el amenazado Pipistrellus madeirensis Look what the cat dragged in: Felis silvestris catus as predators of insular bats and instance of predation on the endangered Pipistrellus maderensis

Research paper thumbnail of Políticas sectoriales en Colombia: evolución y propuestas

El presente capítulo dedicado a las PS en Colombia se encuentra estructurado en cinco secciones. ... more El presente capítulo dedicado a las PS en Colombia se encuentra estructurado en cinco secciones. La primera corresponde a su motivación contenida en la literatura. En la siguiente, se ilustra la experiencia nacional según los Planes de Desarrollo y la comparación internacional, una reseña de su implementación, un balance de la competitividad y lecciones aprendidas. En la tercera sección se dedica su viabilidad frente a la actualidad del entorno. La penúltima sección se dedica a las propuestas vigentes y sus posibilidades, un análisis de casos de PS destinadas a corregir fallas de mercado (transversales) y PS orientadas a promover sectores: exportaciones y un puñado de actividades económicas. Finalmente, la usual sección de consideraciones y recomendaciones

Research paper thumbnail of CHRISTIAN-ALBRECHTS-UNIVERSITAT ZU KIEL

Research paper thumbnail of Street vendors and public space: The effects on commerce in Bogotá

Research paper thumbnail of Fac. of Sci., Univ. of Porto, Porto, Portugal

Research paper thumbnail of Or-Parallel Prolog Execution on Clusters of Multicores

Research paper thumbnail of Novel Models for Or-Parallel Logic Programs: A Performance Analysis

Lecture Notes in Computer Science, 2000

One of the advantages of logic programming is the fact that it offers many sources of implicit pa... more One of the advantages of logic programming is the fact that it offers many sources of implicit parallelism, such as and-parallelism and or-parallelism. Arguably, or-parallel systems, such as Aurora and Muse, have been the most successful parallel logic programming systems so far. Or-parallel systems rely on techniques such as Environment Copying to address the problem that branches being explored in parallel may need to assign different bindings for the same shared variable. Recent research has led to two new binding representation approaches that also support independent and-parallelism: the Sparse Binding Array and the Copy-On-Write binding models. In this paper, we investigate whether these newer models are practical alternatives to copying for or-parallelism. We based our work on YapOr, an or-parallel copying system using the YAP Prolog engine, so that the three alternative systems share schedulers and the underlying engine.

Research paper thumbnail of Achieving scalability in parallel tabled logic programs

Proceedings 16th International Parallel and Distributed Processing Symposium, 2002

Tabling or memoing is a technique where one stores intermediate answers to a problem so that they... more Tabling or memoing is a technique where one stores intermediate answers to a problem so that they can be reused in further calls. Tabling is of interest to logic programming because it addresses some of most significant weaknesses of Prolog. Namely, it can guarantee termination for programs with the bounded term-size property. Tabled programs exhibit a more complex execution mechanism than traditional Prolog's left-to-right search with backtracking. The reason is that Prolog programs are highly recursive and generate multiple answers. This rather involved execution mechanism requires a more complex implementation than traditional Prolog.

Research paper thumbnail of IMPACT: Innovative Models for Prolog with Advanced Control and Tabling

International Conference on Logic Programming/Joint International Conference and Symposium on Logic Programming, 2005

During the past years, our research group has been working in the design and implementation of Lo... more During the past years, our research group has been working in the design and implementation of Logic Programming Systems. In previous work, we have produced systems to support sequential, parallel and distributed execution of Prolog; to support novel techniques and models, such as tabling, through the YapTab system [1], or the Extended Andorra Model (EAM), through the BEAM [2]; and

Research paper thumbnail of Look what the cat dragged in: Felis silvestris catus as predators of insular bats and instance of predation on the endangered Pipistrellus maderensis

This note reports the predation of a threatened Madeira pipistrelle bat by a domestic house cat. ... more This note reports the predation of a threatened Madeira pipistrelle bat by a domestic house cat. This represents the first confirmed record of cat predation upon a Macaronesian bat and adds to an increasing body of evidence suggesting that free-ranging cats pose a strong negative impact to native insular vertebrate populations.

Research paper thumbnail of Birds in humanized landscapes: Sao Tomé endemic birds’ response to agricultural intensification

Research paper thumbnail of An Or-Parallel Prolog Execution Model for Clusters of Multicores

Research paper thumbnail of A Portable Prolog Predicate for Printing Rational Terms

Research paper thumbnail of A Parallel Virtual Machine for Executing Forward-Chaining Linear Logic Programs

Research paper thumbnail of A Simple and E cient Lock-Free Hash Trie Design for Concurrent Tabling

Research paper thumbnail of Design and Implementation of a Multithreaded Virtual Machine for Executing Linear Logic Programs

Research paper thumbnail of A Hybrid MapReduce Model for Prolog

Research paper thumbnail of Predation note: Anthus berthelotii madeirensis (Passeriformes: Motacillidae) catches Teira dugesii mauli (Squamata: Lacertidae) in Deserta Grande, Madeira Archipelago

Research paper thumbnail of EXTERNALIDADES DE PROYECTOS DE INFRAESTRUCTURA URBANA MEDICIÓN, VALORACION, INTERNALIZACION Y OPCIONES DE POLITICA EN AMERICA LATINA Y EL CARIBE: EL CASO DE METROVIVIENDA EN BOGOTÁ

Se describen los principales rasgos de las ciudadelas de MV en términos de características y meta... more Se describen los principales rasgos de las ciudadelas de MV en términos de características y metas, así como su esquema de gestión y resultados. Se contextualiza MV de acuerdo con el problema de la producción de suelo para la vivienda de interés social VIS, haciendo una reseña de los patrones de poblamiento de la ciudad y las condiciones de las localidades intervenidas por MV y las políticas de promoción de megaproyectos urbanos. Se analizan los costos y beneficios de MV para lo cual procede a realiza presentar una actualización de una evaluación pasada frente a la evolución reciente, se discuten sus alcance y limitaciones. A continuación, se hace una identificación de las externalidades de MV según sus componentes, las dimensiones urbanas del desarrollo sostenible, los atributos económicos de los bienes y los riesgos inherentes a la gestión. Se cualifica la correspondencia entre las externalidades y las políticas de urbanisticas de Bogota. Una focalización de la población de acuerdo a las externalidades identificadas y se realiza una discusión de las magnitudes conocidas.

Research paper thumbnail of Evidence of long-term stability in the iris pattern of Tarentola geckos

Research paper thumbnail of Felis silvestris catus como predador de murciélagos insulares y cita de depredación sobre el amenazado Pipistrellus madeirensis Look what the cat dragged in: Felis silvestris catus as predators of insular bats and instance of predation on the endangered Pipistrellus maderensis

Research paper thumbnail of Políticas sectoriales en Colombia: evolución y propuestas

El presente capítulo dedicado a las PS en Colombia se encuentra estructurado en cinco secciones. ... more El presente capítulo dedicado a las PS en Colombia se encuentra estructurado en cinco secciones. La primera corresponde a su motivación contenida en la literatura. En la siguiente, se ilustra la experiencia nacional según los Planes de Desarrollo y la comparación internacional, una reseña de su implementación, un balance de la competitividad y lecciones aprendidas. En la tercera sección se dedica su viabilidad frente a la actualidad del entorno. La penúltima sección se dedica a las propuestas vigentes y sus posibilidades, un análisis de casos de PS destinadas a corregir fallas de mercado (transversales) y PS orientadas a promover sectores: exportaciones y un puñado de actividades económicas. Finalmente, la usual sección de consideraciones y recomendaciones

Research paper thumbnail of CHRISTIAN-ALBRECHTS-UNIVERSITAT ZU KIEL

Research paper thumbnail of Street vendors and public space: The effects on commerce in Bogotá

Research paper thumbnail of Fac. of Sci., Univ. of Porto, Porto, Portugal

Research paper thumbnail of Or-Parallel Prolog Execution on Clusters of Multicores

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