This chapter is focused on the basic principles behind the utilization of rules in order to perform reasoning about the Web Ontology Language (OWL), a Description Logic-based language that is the W3C recommendation for creating and sharing ontologies in the Semantic Web. More precisely, we elaborate on the entailment-based OWL reasoning (EBOR) paradigm, which is based on the utilization of RDF/...

ELK is a specialized reasoner for the lightweight ontology language OWL EL. The practical utility of ELK is in its combination of high performance and comprehensive support for language features. At its core, ELK employs a consequence-based reasoning engine that can take advantage of multi-core and multi-processor systems. A modular architecture allows ELK to be used as a stand-alone applicatio...

This is the thirteenth 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). The first article [3] introduced ontologies and the Semantic Web, and covered basic concepts in the Resource Description Fr...

This is the twelfth 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. The fi...

Abstract Nominal schemas have been proposed as an extension to Description Logics (DL), the knowledge representation paradigm underlying Web Ontology Language (OWL). They provide for a very tight integration of DL and rules. can be understood syntactic sugar on top OWL. However, this naive perspective leads inefficient reasoning procedures. In order develop efficient procedure language ${\mathc...

OWL ontologies are nowadays a quite popular way to describe structured knowledge in terms of classes, relations among classes and class instances. In this paper, given an ontology target T, we address the problem learning fuzzy concept inclusion axioms that sufficient conditions for being individual instance T (and which degree). To do so, present Fuzzy OWL-Boost relies on Real AdaBoost boostin...