The Semantic Web attempts to reach a state in the future where everything on the Web will no longer be only machine-readable, but also machine-understandable. An ontology is an explicit specification of a conceptualization. A conceptualization is an abstract, simplified…

The term Federated Databases refers to the data integration of distributed, autonomous and heterogeneous databases. However, a federation can also include information systems, not only databases. At integrating data, several issues must be addressed. Here, we focus on the problem…

The studies of Relational Data Base Management Systems and Databases constitute nowadays a main tren of investigation in large businesses and universities of the entire world. The creation of a data base engine keeps being a challenge since there are…

Vertical partitioning, in which attributes of a relation are
assigned to partitions, is aimed at improving database
performance. We extend previous research that is based on
a single relation to multi-relation database environment,
by including referential integrity constraints, access time

This paper is an attempt to define how a
specific data structure might be used to
store, in a persistent manner, temporal
information during a computer simulation.
In particular, it considers the sort of
temporal information generated during a
discrete…

We describe the design, implementation and deployment of the multi-level agent-based system architecture developed for the SEWASIE project. The aim of the system is to help the user in querying heterogeneous data sources which are integrated by means of ontologies.…

A data warehouse efficiently processes a given set of queries by utilizing the multiple materialized views. Owing to the constraint on space and maintenance cost, the materialization of all views is unfeasible. One of the critical decisions involved in the…

The concept of “approximate” searching has applications in a vast number of fields. Some examples are non-traditional databases (e. g. storing images, fingerprints or audio clips, where the concept of exact search is of no use and we search instead…

Most information in science, engineering and business has been recorded in form of text. This information can be found online in the World-Wide-Web. One of the major tools to support information access are the search engines which usually use information…

Similarity search is a fundamental operation for applications that deal with unstructured data sources. In this paper we propose a new pivot-based method for similarity search, called Sparse Spatial Selection (SSS).
The main characteristic of this method is that it…