564 research outputs found
Variational description of Gibbs-non-Gibbs dynamical transitions for spin-flip systems with a Kac-type interaction
We continue our study of Gibbs-non-Gibbs dynamical transitions. In the
present paper we consider a system of Ising spins on a large discrete torus
with a Kac-type interaction subject to an independent spin-flip dynamics
(infinite-temperature Glauber dynamics). We show that, in accordance with the
program outlined in \cite{vEFedHoRe10}, in the thermodynamic limit
Gibbs-non-Gibbs dynamical transitions are \emph{equivalent} to bifurcations in
the set of global minima of the large-deviation rate function for the
trajectories of the empirical density \emph{conditional} on their endpoint.
More precisely, the time-evolved measure is non-Gibbs if and only if this set
is not a singleton for \emph{some} value of the endpoint. A partial description
of the possible scenarios of bifurcation is given, leading to a
characterization of passages from Gibbs to non-Gibbs and vice versa, with sharp
transition times.
Our analysis provides a conceptual step-up from our earlier work on
Gibbs-non-Gibbs dynamical transitions for the Curie-Weiss model, where the
mean-field interaction allowed us to focus on trajectories of the empirical
magnetization rather than the empirical density.Comment: Key words and phrases: Curie-Weiss model, Kac model, spin-flip
dynamics, Gibbs versus non-Gibbs, dynamical transition, large deviation
principles, action integral, bifurcation of rate functio
A Proof-of-Concept for Orthographic Named Entity Correction in Spanish Voice Queries
Proceedings of: 10th International Workshop on Adaptive Multimedia Retrieval. Took place October 24-25, 2012, in Copenhaguen (Denmark).Automatic speech recognition (ASR) systems are not able to recognize entities that are not present in its vocabulary. The problem considered in this paper is the misrecognition of named entities in Spanish voice queries introducing a proof-of-concept for named entity correction that provides alternative entities to the ones incorrectly recognized or misrecognized by retrieving entities phonetically similar from a dictionary. This system is domain-dependent, using sports news, especially football news, regardless of the automatic speech recognition system used. The correction process exploits the query structure and its semantic information to detect where a named entity appears. The system finds the most suitable alternative entity from a dictionary previously generated with the existing named entities.This work has been partially supported by the Regional Government of
Madrid under the Research Network MA2VICMR (S2009/TIC-1542) and by the Spanish Center
for Industry Technological Development (CDTI, Ministry of Industry, Tourism and Trade)
through the BUSCAMEDIA Project (CEN-20091026).Publicad
Biomorphic ceramics from wood-derived precursors
Materials development is driven by microstructural complexity and, in many cases, inspired by biological systems such as bones, shells and wood. In one approach, one selects the main microstructural features responsible for improved properties and design processes to obtain materials with such microstructures (continuous-fibre-reinforced ceramics, porous ceramics, fibrous ceramic monoliths, etc.). In a different approach, it is possible to use natural materials directly as microstructural templates. Biomorphic ceramics are produced from natural and renewable resources (wood or wood-derived products). A wide variety of SiC-based ceramics can be fabricated by infiltration of silicon or silicon alloys into cellulose-derived carbonaceous templates, providing a low-cost route to advanced ceramic materials with near-net shape potential and amenable to rapid prototyping. These materials have tailorable microstructure and properties, and behave like ceramic materials manufactured by advanced ceramic processing approaches. This review aims to be a comprehensive description of the development of bioSiC ceramics: from wood templates and their microstructure to potential applications of bioSiC materials.Ministerio de Economía y Competitividad MAT2016-76526-R, MAT2013-41233-
An Illustrated Methodology for Evaluating ASR Systems
Proceeding of: 9th International Workshop on Adaptive Multimedia Retrieval (AMR 2011) Took place 2011, July, 18-19, in Barcelona, Spain. The event Web site is http://stel.ub.edu/amr2011/Automatic speech recognition technology can be integrated in an information retrieval process to allow searching on multimedia contents. But, in order to assure an adequate retrieval performance is necessary to state the quality of the recognition phase, especially in speaker-independent and domainindependent environments. This paper introduces a methodology to accomplish the evaluation of different speech recognition systems in several scenarios considering also the creation of new corpora of different types (broadcast news, interviews, etc.), especially in other languages apart from English that are not widely addressed in speech community.This work has been partially supported by the Spanish Center for Industry Technological Development (CDTI, Ministry of Industry, Tourism and Trade), through the BUSCAMEDIA Project (CEN-20091026). And also by MA2VICMR: Improving the access, analysis and visibility of the multilingual and multimedia information in web for the Region of Madrid (S2009/TIC-1542).Publicad
Proof of Concept of Ontology-based Query Expansion on Financial Domain
Este trabajo presenta el uso de una ontología en el dominio financiero para la expansión de consultas con el fin de mejorar los resultados de un sistema de recuperación de información (RI) financiera. Este sistema está compuesto por una ontología y un índice de Lucene que permite recuperación de conceptos identificados mediante procesamiento de lenguaje natural. Se ha llevado a cabo una evaluación con un conjunto limitado de consultas y los resultados indican que la ambigüedad sigue siendo un problema al expandir la consulta. En ocasiones, la elección de las entidades adecuadas a la hora de expandir las consultas (filtrando por sector, empresa, etc.) permite resolver esa ambigüedad.This paper explains the application of ontologies in financial domains to a query
expansion process. The final goal is to improve financial information retrieval effectiveness.
The system is composed of an ontology and a Lucene index that stores and retrieves natural
language concepts. An initial evaluation with a limited number of queries has been performed.
Obtained results show that ambiguity remains a problem when expanding a query. The filtering
of entities in the expansion process by selecting only companies or references to markets helps
in the reduction of ambiguity.Este trabajo ha sido parcialmente financiado por el proyecto Trendminer (EU FP7-ICT287863) , el proyecto Monnet (EU FP7-ICT 247176) y MA2VICMR (S2009/TIC-1542).Publicad
Porous Graphene-like Carbon from Fast Catalytic Decomposition of Biomass for Energy Storage Applications
A novel carbon material made of porous graphene-like nanosheets was synthesized from biomass resources by a simple catalytic graphitization process using nickel as a catalyst for applications in electrodes for energy storage devices. A recycled fiberboard precursor was impregnated with saturated nickel nitrate followed by high-temperature pyrolysis. The highly exothermic combustion of in situ formed nitrocellulose produces the expansion of the cellulose fibers and the reorganization of the carbon structure into a three-dimensional (3D) porous assembly of thin carbon nanosheets. After acid washing, nickel particles are fully removed, leaving nanosized holes in the wrinkled graphene-like sheets. These nanoholes confer the resulting carbon material with ≈75% capacitance retention, when applied as a supercapacitor electrode in aqueous media at a specific current of 100 A·g–1 compared to the capacitance reached at 20 mA·g–1, and ≈35% capacity retention, when applied as a negative electrode for lithium-ion battery cells at a specific current of 3720 mA·g–1 compared to the specific capacity at 37.2 mA·g–1. These findings suggest a novel way for synthesizing 3D nanocarbon networks from a cellulosic precursor requiring low temperatures and being amenable to large-scale production while using a sustainable starting precursor such as recycled fiberwood.Spanish Government Agency Ministerio de Economí a y Competitividad (MINECO) (grant number MAT2016-76526-R)
Evaluación clínica, análisis evolutivo y particularidades de la obesidad infarto-juvenil
Tesis doctoral inédita leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Pediatría. Fecha de lectura: 08-11-201
Some Experiments in Evaluating ASR Systems Applied to Multimedia Retrieval
Proceedings of: 7th International Workshop on Adaptive Multimedia Retrieval (AMR 2009). Took place 2009, September 24-25, in Madrid. The event Web site is http://nlp.uned.es/amr2009/This paper describes some tests performed on different types of voice/audio input applying three commercial speech recognition tools. Three multimedia retrieval scenarios are considered: a question answering system, an automatic transcription of audio from video files and a real-time captioning system used in the classroom for deaf students. A software tool, RET (Recognition Evaluation Tool), has been developed to test the output of commercial ASR systems.This research work has been supported by the Regional Government of Madrid under the Research Network MA2VICMR (S2009/TIC-1542) and by the Spanish Ministry of Education under the project BRAVO (TIN2007-67407-C03-01).Publicad
Alteración de las propiedades mecánicas por formación de precipitado en ZrO2 parcialmente estabilizado con Y2O3
Se ha estudiado el comportamiento mecánico a altas temperaturas del Zr02 monocristalino parcialmente estabilizado con 4. 7 mol% de Y 203, mediante ensayos de velocidad de deformación constante, a 1.4xl0·5 s· 1, en aire a 1400 °C. Las muestras fueron sometidas a tratamientos térmicos a 1600 °C antes de la deformación. Se ha realizado un estudio detallado de la interacción dislocación-precipitado mediante microscopía electrónica de transmisión, para explicar el comportamiento observado, proponiendo un modelo de deformación.Single crystals of partially-stabilized Zr02 contammg 4. 7 mol% Y 203 were deformed by constan! strain rates of 1.4x10·5 s·1, in air at 1400 °C. The samples were annealed at 1600 °C prior to deformation. TEM studies of the dislocation-precipitate interaction were performed to explain the observed behavior, and a model for the deformation is suggested
High-temperature mechanical behavior of polycrystalline yttrium-doped barium cerate perovskite
The high-temperature mechanical properties of the mixed ionic-electronic conductor perovskite BaCe0.95Y0.05O3-δ with average grain size of 0.40μm have been studied in compression between 1100 and 1300°C in air at different initial strain rates. The true stress-true strain curves display an initial stress drop, followed by an extended steady-state stage. As the temperature decreases and/or the strain rate increases, there is a transition to a damage-tolerant strain-softening stage and eventually to catastrophic failure. Analysis of mechanical and microstructural data revealed that grain boundary sliding is the primary deformation mechanism. The strength drop has been correlated with the growth of ultrafine grains during deformation, already present at grain boundaries and triple grain junctions in the as-fabricated material.Ministerio de Ciencia e Innovación MAT2009-13979-C03-0
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