This is the first in a series of articles on ontology-based approaches to modeling. The main focus is on popular ontology languages proposed for the Semantic Web, such as the Resource Description Framework (RDF), RDF Schema (RDFS), and the Web Ontology Language (OWL). OWL is based on description logic. A later series of articles will explore other logic-based languages such as Datalog. This fir...

Although the model-theoretic semantics of the languages used in the Semantic Web are crisps, the need arise to extend them to represent fuzzy data, in the same way fuzzy logic extend first-orderlogic. We will define a fuzzy counterpart of the RDF Model Theory for RDF (section 2) and RDF Schema (section 3). Last, we show how to implement the extended semantics in inference rules (section 4).

The efficiency of SPARQL query evaluation against Linked Open Data may benefit from schema-based indexing. However, many data items come with incomplete schema information or lack schema descriptions entirely. In this position paper, we outline an approach to an indexing of linked data graphs based on schemata induced through Formal Concept Analysis. We show how to map queries onto RDF graphs b...

There is a growing interest in the validation of RDF based solutions where one can express the topology of an RDF graph using some schema language that can check if RDF documents comply with it. Shape Expressions have been proposed as a simple, intuitive language that can be used to describe expected graph patterns and to validate RDF graphs against those patterns. The syntax and semantics of S...

The standard SPARQL query language is currently defined for querying RDF graphs without RDFS semantics. Several extensions to SPARQL have been proposed to query RDF graphs considering RDFS semantics. In this paper, we discuss extensions of SPARQL that uses regular expressions to navigate RDF graphs and may be used to answer queries considering RDFS semantics. In particular, we present and compa...

To create new added value the Semantic Web has to provide new means for business integration enabling open world-wide cooperation between various enterprises. Existing business integration techniques assume the enterprises having similar conceptual models of the objects being exchanged, and this limits their application areas. The Semantic Web needs to possess a technique capable of mapping dif...

The Semantic Web is a vision of enabling software agents to autonomously understand, process and integrate Web resources. This ability is based on semantically marking up Web resources using ontologies. Ontology languages are based on Resource Description Framework (RDF) and RDF Schema (RDFS), which form the foundation of the Semantic Web. In this paper, we define the RDF framework in terms of ...

Rather than thinking of XML and RDF as competing alternatives, we regard XML and RDF as complementary technologies. This paper discusses bidirectional mapping between XML and RDF, the problem of lift. Rather than inventing a new mapping language, we use information already available in the XML schema. The result is a tool, Gloze that works within the Jena framework. This is illustrated by examp...

Application testing is a critical component of application development. Testing of Semantic Web applications requires large RDF datasets, conforming to an expected form or schema, and preferably, to an expected data distribution. Finding such datasets often proves impossible, while generating input datasets is often cumbersome. The GRR (Generating Random RDF) system is a convenient, yet powerfu...

Resource Description Framework (RDF) has been widely used as a W3C standard to describe the resource information in the Semantic Web. A standard SPARQL query over RDF data requires query issuers to fully understand the domain knowledge of the data. Because of this fact, SPARQL queries over RDF data are not flexible and it is difficult for non-experts to create queries without knowing the underl...