Abstract: Ontologies and various semantic repositories became a convenient approach for implementing model-driven architectures of distributed systems on the Web. SPARQL is the standard query language for querying such. However, although SPARQL is well-established standard for querying semantic repositories in RDF and OWL format and there are commonly used APIs which supports it, like Jena for Java, its parallel option is not incorporated in them. This article presents a complete framework consisting of an object algebra for parallel RDF and an index-based implementation of the parallel query engine capable of dealing with the distributed RDF ontologies which share common vocabulary. It has been implemented in Java, and for validation of the algorithms has been applied to the problem of organizing virtual exhibitions on the Web.
Abstract: Radio Frequency Identification (RFID) has become a
key technology in the emerging concept of Internet of Things (IoT).
Naturally, business applications would require the deployment of
various RFID systems developed by different vendors that use
different data formats and structures. This heterogeneity poses a
challenge in developing real-life IoT systems with RFID, as
integration is becoming very complex and challenging. Semantic
integration is a key approach to deal with this challenge. To do so,
ontology for RFID systems need to be developed in order to
annotated semantically RFID systems, and hence, facilitate their
integration. Accordingly, in this paper, we propose ontology for
RFID systems. The proposed ontology can be used to semantically
enrich RFID systems, and hence, improve their usage and reasoning.
Abstract: The enormous amount of information stored on the
web increases from one day to the next, exposing the web currently
faced with the inevitable difficulties of research pertinent information
that users really want. The problem today is not limited to expanding
the size of the information highways, but to design a system for
intelligent search. The vast majority of this information is stored in
relational databases, which in turn represent a backend for managing
RDF data of the semantic web. This problem has motivated us to
write this paper in order to establish an effective approach to support
semantic transformation algorithm for SPARQL queries to SQL
queries, more precisely SPARQL SELECT queries; by adopting this
method, the relational database can be questioned easily with
SPARQL queries maintaining the same performance.
Abstract: A large amount of data is typically stored in relational
databases (DB). The latter can efficiently handle user queries which
intend to elicit the appropriate information from data sources.
However, direct access and use of this data requires the end users to
have an adequate technical background, while they should also cope
with the internal data structure and values presented. Consequently
the information retrieval is a quite difficult process even for IT or DB
experts, taking into account the limited contributions of relational
databases from the conceptual point of view. Ontologies enable users
to formally describe a domain of knowledge in terms of concepts and
relations among them and hence they can be used for unambiguously
specifying the information captured by the relational database.
However, accessing information residing in a database using
ontologies is feasible, provided that the users are keen on using
semantic web technologies. For enabling users form different
disciplines to retrieve the appropriate data, the design of a Graphical
User Interface is necessary. In this work, we will present an
interactive, ontology-based, semantically enable web tool that can be
used for information retrieval purposes. The tool is totally based on
the ontological representation of underlying database schema while it
provides a user friendly environment through which the users can
graphically form and execute their queries.
Abstract: In the last few years, the Semantic Web gained scientific acceptance as a means of relationships identification in knowledge base, widely known by semantic association. Query about complex relationships between entities is a strong requirement for many applications in analytical domains. In bioinformatics for example, it is critical to extract exchanges between proteins. Currently, the widely known result of such queries is to provide paths between connected entities from data graph. However, they do not always give good results while facing the user need by the best association or a set of limited best association, because they only consider all existing paths but ignore the path evaluation. In this paper, we present an approach for supporting association discovery queries. Our proposal includes (i) a query language PmSPRQL which provides a multiparadigm query expressions for association extraction and (ii) some quantification measures making easy the process of association ranking. The originality of our proposal is demonstrated by a performance evaluation of our approach on real world datasets.