SWDB-ODBIS07: Joint ODBIS & SWDB workshop on Semantic Web, Ontologies, Databases

Colocated with VLDB2007

September 24, 2007

Keynote Talks

Invited Speaker : Marcelo Arenas, Catholic University, Chile


Title: SPARQL over RDF, and its possible extensions to RDFS

Abstract: The Resource Description Framework (RDF) is the W3C recommendation language for representing metadata about Web resources. It is the basic data layer of the Semantic Web. The driving idea in the development of RDF was to create a language to represent information in a flexible way. It turns out that the impact of the proposal goes far beyond the initial goal, particularly as a model for representing information with a graph-like structure.

In the first part of this talk, we focus on querying RDF data. SPARQL is the W3C candidate recommendation query language for RDF. In this talk we address systematically the formal study of SPARQL, concentrating in its graph pattern facility. We consider for this study a fragment which encompasses all the main issues yet is simple to formalize. We provide a compositional semantics and study the complexity of query evaluation.

RDF Schema (RDFS) extends RDF with a schema vocabulary (subPropertyOf, subClassOf, domain, range, type, etc) with a predefined semantics. Evaluating queries which involve this vocabulary is challenging, and there is not yet consensus in the Semantic Web community on how to define a query language for RDFS. In the second part of this talk, we introduce a language for querying RDFS data. This language extends SPARQL, and its formal design is grounded on standard relational algebra plus Kleene star with operators for navigating triples subject to constraints. We provide a formal semantics for this language, and also study the complexity of query evaluation.

This is joint work with Claudio Gutierrez and Jorge Perez.

Marcelo Arenas, Pontificia Universidad Católica de Chile.
Home Page: http://www.ing.puc.cl/~marenas

Short Bio: Prof. Marcelo Arenas received B.Sc. degrees in Mathematics (1997) and Computer Engineering (1998) and a M.Sc. degree in Computer Science (1998) from the Pontificia Universidad Católica de Chile, and a Ph.D. degree in Computer Science (2005) from the University of Toronto, Canada.
In 2005, he joined the Computer Science Department at the Pontificia Universidad Católica de Chile as an Assistant Professor. His research interests are in different aspects of database theory, such as expressive power of query languages, database semantics, integrity constraints, inconsistency handling, database design, XML databases, data exchange and database aspects of the semantic web. Marcelo has received an IBM Ph.D. Fellowship (2004), three best paper awards (PODS 2003 in San Diego, California, PODS 2005 in Baltimore, Maryland and ISWC 2006 in Athens, Georgia) and an Honorable Mention Award in 2006 from the ACM Special Interest Group on Management of Data (SIGMOD) for his Ph.D dissertation, ``Design Principles for XML Data.''

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