The quest for information retrieval on the semantic web

Semantic search has been one of the motivations of the Semantic Web since it was envisioned. We propose a model for the exploitation of ontology-based KBs to improve search over large document repositories. The retrieval model is based on an adaptation of the classic vector-space model, including an annotation weighting algorithm, and a ranking algorithm. Semantic search is combined with keyword-based search to achieve tolerance to KB incompleteness. Our proposal has been tested on corpora of significant size, showing promising results with respect to keyword-based search, and providing ground for further analysis and research

Heuristicas y metaconocimiento en resolucion automatica de problemas de matematicas

Centro de Informacion y Documentacion Cientifica (CINDOC). C/Joaquin Costa, 22. 28002 Madrid. SPAIN / CINDOC - Centro de Informaciòn y Documentaciòn CientìficaSIGLEESSpai

Offline evaluation options for recommender systems

We undertake a detailed examination of the steps that make up offline experiments for recommender system evaluation, including the manner in which the available ratings are filtered and split into training and test; the selection of a subset of the available users for the evaluation; the choice of strategy to handle the background effects that arise when the system is unable to provide scores for some items or users; the use of either full or condensed output lists for the purposes of scoring; scoring methods themselves, including alternative top-weighted mechanisms for condensed rankings; and the application of statistical testing on a weighted-by-user or weighted-by-volume basis as a mechanism for providing confidence in measured outcomes. We carry out experiments that illustrate the impact that each of these choice points can have on the usefulness of an end-to-end system evaluation, and provide examples of possible pitfalls. In particular, we show that varying the split between training and test data, or changing the evaluation metric, or how target items are selected, or how empty recommendations are dealt with, can give rise to comparisons that are vulnerable to misinterpretation, and may lead to different or even opposite outcomes, depending on the exact combination of settings usedThe frst two authors were funded in part by Grant TIN2016-80630-P from the Spanish Ministry of Science, Innovation and Universitie

Un sistema de presentación dinámica hipermedia para representaciones

Los sistemas web adaptativos presentan información al usuario en documentos hipermedia generados dinámicamente de acuerdo con un modelo automáticamente actualizado del usuario. Por lo general los sistemas adaptativos existentes imponen un modelo fijo para representar el conocimiento que maneja la aplicación. Por otra parte, utilizan patrones invariables de diseño de página para los documentos generados, que no pueden ser libremente configurados por un diseñador humano. En este artículo proponemos un sistema genérico de presentación para sistemas hipermedia de enseñanza adaptativa altamente independiente de la representación del conocimiento del dominio y del mantenimiento del estado de la aplicación. La generalidad se consigue proporcionando un marco de aplicación para la definición de ontologías que mejor se ajustan a un dominio o un autor concreto. La presentación de las páginas a generar se describe en términos de clases y relaciones de la ontología. Un modelo explícito de la presentación, separado de los contenidos del curso, se utiliza para permitir a los diseñadores un extenso control sobre la generación de todos los aspectos de la presentación, con un coste de desarrollo moderado

Improving the access, analysis and visibility of the information and the multilingual and multimedia net content for the Madrid Community

Presentación de las actividades del segundo programa de la red de investigación MAVIR de la Comunidad de Madrid.Presentation of the second program activities of the research net MAVIR of Madrid Region