I. Introduction
One of the most important contributions of the Semantic Web [1] is introduction of the Resource Description Framework – RDF [16]. RDF becomes the fundamental data representation format of Linked Open Data (LOD) paradigm [2], [6]. In LOD, all the information is represented as a vast network of interconnected basic RDF elements called RDF triples. An RDF triple contains three elements: <subject-property-object>. A subject is an element that a particular piece of information is about, an object is an element that describes the subject, and a property indicates relationship between the subject and the object of a given triple. In general, a set of triples with the same subject in each triple constitutes a description of an entity represented by the subject.