Research On Semantic Web Based On Rough Description Logics

In recent years, many researchers have focused on investigating the Semantic Web.Regarded as an extension of the current World Wide Web, the Semantic Web aims to helpcomputers to understand and process web information automatically. The process of theSemantic Web can be described as follows: firstly a machine-readable meaning is added toweb pages; secondly share terms in web resources can be precisely represented by ontologies；finally knowledge representation technologies are utilized for automated reasoning from Webresources.Web Ontology Language(OWL) is a standard ontology language, can representknowledge for the Semantics Web, can be used in a lot of areas, such as biology, geography,astronomy, defense, and the automotive and aerospace industries, and so on. OWL includesthree sublanguages: OWL Lite, OWL DL and OWL Full. The expressive power of the threesublanguages are gradually increasing, but the complexities are gradually declining. Moreover,OWL DL can be regarded as very expressive DLs with an RDF syntax, has high expressivepower and good reasoning efficiency. Therefore, there is a very close relationship beteweenOWL DL and description logics.Generally, DLs are a class of knowledge representation languages, and can model anapplication domain of interest by a structured and formally well-understood way. Moreover,DLs can be used in various areas, for example, Semantic Web, Ontologies, softwareengineering.Unfortunately, OWL DL and DLs can not well model a great deal of real-world problemsbecause of the restriction represented formalism. Now, how to enhance the expessive powerof OWL DL and DLs, is a research focus for semantic web.This paper studies OWL DL and the description logics with higher expressive power. Wefocus on investigating rough OWL DL and rough description logic, and have done thesystematic and in-depth study on the inherent defects of these methods, and carried out aseries of studies by focusing on how to increase the expressive power of OWL DL anddescription logics. We proposed rough OWL DL-ROWL DL, and rough description logic-RSHOIN(D). The main contribution of this paper and research results are as follows:1) We proposed rough description logic-RSHOIN(D) in order to increase the expressivepower of description logics. RSHOIN(D) is a extension of SHOIN(D) and rough settheory. Firslty, we defined the syntax and semantics of RSHOIN(D), and then weprovided reasoning problems, and proved that all reasoning problems can betranslated into satisfiability of knowledge base, finally, we present an relationship between RSHOIN(D) and SHOIN(D), and prove the efficiency of RSHOIN(D)reasoning.2) We proposed rough OWL DL-ROWL DL in order to increase the expressive powerof OWL DL. ROWL DL is a combination of OWL DL and rough set theory. Firstly,we proposed approximationclass, and presented five approximationclass axioms, andthen we defined the syntax and semantics of ROWL DL, finally, we provided arelationship between ROWL DL and RSHOIN(D), and proved that entailmentbetween ROWL DLs can be reduced to unsatisfiability of RSHOIN(D) knowledgebase.