schema matching is a critical step in many applications, such as data warehouse loading, online analytical process (olap), data mining, semantic web [2] and schema integration. this task is defined for finding the semantic correspondences between elements of two schemas. recently, schema matching has found considerable interest in both research and practice. in this paper, we present a new impr...

The aim of the Edutella project is to provide a peer-to-peer infrastructure for educational material retrieval using semantic web meta-data descriptions of educational resources. Edutella uses the semantic web meta-data description languages RDF and RDF-Schema for describing web resources. The aim of this work is to wrap the Edutella infrastructure with a functional mediator system. This makes ...

Many approaches for RDF stores exist, most of them using very straight-forward techniques to store triples in or mapping RDF Schema classes to database tables. In this paper we propose an RDF store that uses a natural mapping of RDF resources to database tables that does not rely on RDF Schema, but constructs a schema based on the occurring signatures, where a signature is the set of properties...

RDF Schema provides means to define vocabulary, structure and constraints for expressing metadata about Web resources. However, formal semantics for the primitives defined in RDF Schema are not provided, and the expressivity of these primitives is not enough for full-fledged ontological modeling and reasoning. To perform these tasks, an additional layer on top of RDF Schema is needed. In this p...

The Semantic Web is a candidate for the next generation of the World Wide Web. It is anticipated that the number of metadata written in RDF (Resource Description Framework) and RDF Schema will increase as the Semantic Web becomes popular. In such a situation, demand for querying metadata described with RDF and RDF Schema will also increase, and therefore effective query retrieval of RDF data is...

A huge amount of data on the Web may be heterogeneous with respect to syntax, schemata and semantics. For instance, XML and RDF provide two completely different paradigms for modeling Web data. In this paper, we focus on the issue of mapping representations in an ontology-based framework that aims at integrating XML and RDF sources. We propose a solution that utilizes a new mapping language cal...

There have been several attempts to make RDBMS and RDF stores inter-operate. The most popular one, D2RQ, has explored one direction i.e. to look at RDBMS through RDF lenses. In this paper we present RETRO, which investigates the reverse direction i.e. to look at RDF through Relational lenses. RETRO generates a relational schema from an RDF store, enabling a user to query RDF data using SQL. A s...

We propose a path-based scheme for storage and retrieval of RDF data using a relational database. The Semantic Web is much anticipated as the nextgeneration web where high-level processing of web resources are enabled by underlying metadata described in RDF format. A typical application of RDF is to describe ontologies or dictionaries, but in such applications, the size of RDF data is large. As...

We propose a declarative update language for RDF graphs which is based on the paradigms of query and view languages RQL and RVL. Our language, called RUL, ensures that the execution of the update primitives on nodes and arcs neither violates the semantics of the RDF model nor the semantics of the given RDFS schema. In addition, RUL supports fine-grained updates at the class and property instanc...