Towards a systematic benchmarking of ontology-based query rewriting systems

Query rewriting is one of the fundamental steps in ontologybased data access (OBDA) approaches. It takes as inputs an ontology and a query written according to that ontology, and produces as an output a set of queries that should be evaluated to account for the inferences that should be considered for that query and ontology. Different query rewriting systems give support to different ontology languages with varying expressiveness, and the rewritten queries obtained as an output do also vary in expressiveness. This heterogeneity has traditionally made it difficult to compare different approaches, and the area lacks in general commonly agreed benchmarks that could be used not only for such comparisons but also for improving OBDA support. In this paper we compile data, dimensions and measurements that have been used to evaluate some of the most recent systems, we analyse and characterise these assets, and provide a unified set of them that could be used as a starting point towards a more systematic benchmarking process for such systems. Finally, we apply this initial benchmark with some of the most relevant OBDA approaches in the state of the art

Engineering optimisations in query rewriting for OBDA

Ontology-based data access (OBDA) systems use ontologies to provide views over relational databases. Most of these systems work with ontologies implemented in description logic families of reduced expressiveness, what allows applying efficient query rewriting techniques for query answering. In this paper we describe a set of optimisations that are applicable with one of the most expressive families used in this context (ELHIO¬). Our resulting system exhibits a behaviour that is comparable to the one shown by systems that handle less expressive logics

Ecient Inference-aware RDB2RDF Query Rewriting

RDB2RDF systems generate RDF from relational databases, operating in two dierent manners: materializing the database content into RDF or acting as virtual RDF datastores that transform SPARQL queries into SQL. In the former, inferences on the RDF data (taking into account the ontologies that they are related to) are normally done by the RDF triple store where the RDF data is materialised and hence the results of the query answering process depend on the store. In the latter, existing RDB2RDF systems do not normally perform such inferences at query time. This paper shows how the algorithm used in the REQUIEM system, focused on handling run-time inferences for query answering, can be adapted to handle such inferences for query answering in combination with RDB2RDF systems

Foreign direct investment and regional growth: An analysis of the Spanish case

The massive increase in foreign direct investment (FDI) inflows following the Spanish integration with the now European Union (EU) in 1986, has been one of the most important features shaping the behaviour of the Spanish economy in the last twenty years. In this paper we will try to assess the impact of FDI on regional economic growth following Spain’s entry into the EU, using data for the 17 Spanish regions. The results support the important role played by FDI in promoting productivity growth, for those regions that received higher FDI inflows over the period analyzed.Economic growth, Foreign direct investment, Regions

Dispersal and population structure at different spatial scales in the subterranean rodent Ctenomys australis

This study was funded by grants from Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET, PIP5838), Agencia de Promoción Científica y Tecnológica de la Argentina (PICTO1-423, BID-1728/OC-AR), and the programme ECOS-Sud France/Argentina (A05B01).Background: The population genetic structure of subterranean rodent species is strongly affected by demographic (e.g. rates of dispersal and social structure) and stochastic factors (e.g. random genetic drift among subpopulations and habitat fragmentation). In particular, gene flow estimates at different spatial scales are essential to understand genetic differentiation among populations of a species living in a highly fragmented landscape. Ctenomys australis (the sand dune tuco-tuco) is a territorial subterranean rodent that inhabits a relatively secure, permanently sealed burrow system, occurring in sand dune habitats on the coastal landscape in the south-east of Buenos Aires province, Argentina. Currently, this habitat is threatened by urban development and forestry and, therefore, the survival of this endemic species is at risk. Here, we assess population genetic structure and patterns of dispersal among individuals of this species at different spatial scales using 8 polymorphic microsatellite loci. Furthermore, we evaluate the relative importance of sex and habitat configuration in modulating the dispersal patterns at these geographical scales. Results: Our results show that dispersal in C. australis is not restricted at regional spatial scales (similar to 4 km). Assignment tests revealed significant population substructure within the study area, providing support for the presence of two subpopulations from three original sampling sites. Finally, male-biased dispersal was found in the Western side of our study area, but in the Eastern side no apparent philopatric pattern was found, suggesting that in a more continuous habitat males might move longer distances than females. Conclusions: Overall, the assignment-based approaches were able to detect population substructure at fine geographical scales. Additionally, the maintenance of a significant genetic structure at regional (similar to 4 km) and small (less than 1 km) spatial scales despite apparently moderate to high levels of gene flow between local sampling sites could not be explained simply by the linear distance among them. On the whole, our results support the hypothesis that males disperse more frequently than females; however they do not provide support for strict philopatry within females.Publisher PDFPeer reviewe

Ver, describir y simbolizar en el club de matemáticas de la universidad pedagógica nacional

Este artículo surge como consecuencia de la experiencia de dos de los autores de esta memoria como monitores de investigación durante la fase tres (observación y recolección de la información) del proyecto “El Club de Matemáticas de la Universidad Pedagógica Nacional: Un espacio para identificar talentos matemáticos”, un espacio que busca atender a una población generalmente desatendida, los estudiantes más capaces en matemáticas. Durante la fase de recolección de la información se llevaron a cabo observaciones de las estrategias y procedimientos a los cuales recurrieron los estudiantes participantes en el curso Ecuaciones ofrecido en el primer semestre de 2009 en el Club de Matemáticas. El propósito del curso era abordar el estudio de las ecuaciones a partir de procesos de generalización, para lo cual se propusieron problemas de tipo geométrico y numérico que buscaban evidencias sobre el proceso: ver-describir-escribir, planteado por el grupo Azarquiel. El objetivo de este escrito es mostrar un ejemplo, basado en la trascripción de un video de clase, donde se visualiza la presencia de los tres procesos antes mencionados en la solución dada a un problema matemático planteado a los estudiantes del Club de Matemáticas, y cómo tal solución es el resultado de la interacción social, la discusión y la formulación de acuerdos, guiados por el profesor que orientó el curso en el cual se llevó a cabo la investigación

La logística inversa: una actividad para ser competitivos

El presente ensayo se encamina a brindar una pequeña visión a nuestros empresarios, sobre si ¿Es la logística inversa la actividad que podrían implantar las empresas para lograr la tan anhelada ventaja competitiva?, tomando en cuenta que esta actividad no es nueva en los países más desarrollados. Sin embargo, en nuestro país sería tan novedosa como innovadora, además de acuerdo a las razones en las que se enfoque puede tener toda una gama de beneficios, sin importar que varios de los competidores tomaran esta misma actividad para desarrollar su ventaja competitiva. Siempre podrían diferenciarse cada una de las empresas competidoras, ya que estamos seguros que las estrategias son distintas en cada organización y por supuesto, también van acordes con las actividades que realizan y el producto final que desarrollan sean bienes o servicio

El humor gráfico en los 80: Una mirada al taller del humor

El presente trabajo da una mirada a uno de los proyectos gráficos más importantes de la ciudad de Bogotá dentro de un periodo muy crudo de la historia de nuestro país, y por ende de nuestra capital, agobiadas por los flagelos del narcotráfico, la guerrilla, los paramilitares. En medio de esas dificultades los humoristas gráficos del Taller del Humor lograron con ingenio publicar en periódicos de circulación nacional, en revistas, en televisión, en congresos sus opiniones de lo que percibían como realidad nacional, y aun sabiendo de los riesgos que su profesión presentaba, se dieron a la tarea de expresar de una forma no tan personalizada pero si contundente los más importantes flagelos de la década de los 80. Dentro del trabajo se tienen en cuenta el contexto histórico, el estilo gráfico que bordearon al Taller del Humor, así como también los recursos del humor gráfico que desarrollaron sus dibujantes, especialmente de las dos figuras más representativas del Taller: Jorge Grosso y Bernardo Rincón. Los dos últimos capítulos son estudios de caso de estos dibujantes y en ellos se tiene en cuenta sus referencias gráficas, el estilo de caricatura, y el estilo de historieta que realizaron en un periodo que abarca desde 1982 hasta 1991.Requerimientos de sistema: Adobe Acrobat ReaderThe present work looks at one of the most important graphic projects of the city of Bogota within a very crude period of the history of our country, and therefore of our capital, overwhelmed by the scourges of drug trafficking, the guerrilla, the paramilitaries. In the midst of these difficulties, the graphic comedians of the Taller del Humor ingeniously managed to publish in their national newspapers, magazines, television, congresses their opinions of what they perceived as a national reality, and even knowing the risks that their profession presented , they took on the task of expressing the most important scourges of the 1980s in a way that was not so personalized, but was blunt. within the work the historical context, the graphic style are taken into account that bordered the Humor Workshop are taken into account, as well as the resources of graphic humor developed by its cartoonists, especially the two most representative figures of the Workshop: Jorge Grosso and Bernardo Rincón. The last two chapters are case studies of these cartoonists and they take into account their graphic references, the caricature style, and the cartoon style they made in a period that covers from 1982 to 1991.Magíster en Estética e Historia del Art