TopicViz: Semantic Navigation of Document Collections

When people explore and manage information, they think in terms of topics and themes. However, the software that supports information exploration sees text at only the surface level. In this paper we show how topic modeling -- a technique for identifying latent themes across large collections of documents -- can support semantic exploration. We present TopicViz, an interactive environment for information exploration. TopicViz combines traditional search and citation-graph functionality with a range of novel interactive visualizations, centered around a force-directed layout that links documents to the latent themes discovered by the topic model. We describe several use scenarios in which TopicViz supports rapid sensemaking on large document collections

Pedagogía salesiana de la organización popular

La experiencia de desarrollo comunitario en Salinas de Guaranda, nace de un llamado del obispo salesiano Mons. Cándido Rada, a «anunciar, celebrar y construir» el Reino de Dios, en la zona norte de su diócesis, caracterizada por una extrema pobreza y la dominación de la hacienda. Es fácil leer la presentación del director de la Fundación Familia Salesiana de Salinas, Lcdo. Carlos Méndez a la luz de la pedagogía de Don Bosco. De mi parte me limito simplemente a señalar, en forma de introducción, los elementos fundamentales del estilo educativo salesiano, que han guiado nuestros pasos en forma progresivamente siempre más clara y definida, en su aplicación a los retos del desarrollo

Considerations upon interoperability on pervasive computing environments

Component-based Development is a challenging paradigm, though Pervasive Computing Environments, as a special case of such systems, carry even more complications. Applications must be kept available for users anytime, anywhere no matter the user location. This implies transparency on interconnection of components at run-time. Since components may not be previously evaluated when a user’s context change happen, integration of new components might blur the actual requirements of that system. This implies to consider Interoperability at different levels. This paper reports on those challenges, also discussing the possibility to improve the description of an approach under a formal basis. Thus solution strategies can be better defined and applied.Eje: Ingeniería en SoftwareRed de Universidades con Carreras en Informática (RedUNCI

Ab Initio Molecular Dynamics on the Electronic Boltzmann Equilibrium Distribution

We prove that for a combined system of classical and quantum particles, it is possible to write a dynamics for the classical particles that incorporates in a natural way the Boltzmann equilibrium population for the quantum subsystem. In addition, these molecular dynamics do not need to assume that the electrons immediately follow the nuclear motion (in contrast to any adiabatic approach), and do not present problems in the presence of crossing points between different potential energy surfaces (conical intersections or spin-crossings). A practical application of this molecular dynamics to study the effect of temperature in molecular systems presenting (nearly) degenerate states - such as the avoided crossing in the ring-closure process of ozone - is presented.Comment: published in New J. Phy

Role of porosity in controlling the mechanical and impact behaviours of cement-based materials

14 pages, 12 figures.This work deals with the influence of porosity on the tensile, the compressive and the impact behaviours of two fine cementitious mortars—one with silica fume and one without. The addition of silica fume is shown to change the pore size distribution. The mix without silica fume is characterized by porosity at the scale of the grains of fine sand (approximately 100 μm), while silica fume addition results in a more porous matrix with pore sizes of millimetre-length size. The mortar with silica fume shows a higher quasi-static compressive and flexural strength whereas the mix without silica fume is observed to be less compressible (by irreversible reduction of volume) under heavy confinement pressure (quasi-oedometric tests) and shows better ballistic performance. A numerical simulation of the impact tests employing the Krieg, Swenson and Taylor model, which accounts for both deviatoric and volumetric inelastic behaviour of the material, was undertaken using the data from quasi-oedometric tests. These calculations follow the experimental results and confirm the influence of the macroscopic porosity on the impact performance of cement-based materials.The authors are indebted to the Spanish Comisión Interministerial de Ciencia y Tecnología (Project MAT2002-03339) for the financial support of this work and to the Délégation Générale pour l’Armement (DGA/France) for the mobility grant provided to Dr. Forquin