Abstract—We are interested in the problem of building an ontology in a heterogeneous organization, by taking into account different viewpoints and different terminologies of communities in the organization. Such ontology, that we call multi-viewpoint ontology, confers to the same universe of discourse, several partial descriptions, where each one is relative to a particular viewpoint. In addition, these partial descriptions share at global level, ontological elements constituent a consensus between the various viewpoints. In order to provide response elements to this problem we define a multi- viewpoints knowledge model based on viewpoint and ontology notions. The multi-viewpoints knowledge model is used to formalize the multi-viewpoints ontology in description logics language. Keywords—Description logic, knowledge engineering, ontology, viewpoint. I. INTRODUCTION N recent years ontologies played a major role in knowledge representation. For example, applications of the Semantic Web [1] (i.e., e-commerce, knowledge management, web portals, etc.) are based on ontologies. In the Semantic Web an ontology is a formal conceptualization of a domain of interest, allowing the actors (human and software) to share knowledge. It provides a way of expressing the meaning of concepts in a formal knowledge representation language. Description Logics (DLs) is a designation for a family of knowledge representation languages that are widely used in ontological modelling. An important practical reason for this is that they provide one of the main underpinnings for the OWL Web Ontology Language as standardised by the W3C [2]. Since there are generally several ways of apprehending knowledge of a domain, the ontologies construction is therefore not an easy task. This is due primarily to the difficulty of finding consensus definitions of concepts in a domain satisfying the definition of each user, which reflect his viewpoint on the domain. The difficulty of building ontologies is mainly related to the existence of several user communities who can be interested in the same domain but with different viewpoints. These communities evolving in a multidisciplinary environment coexist and collaborate among themselves. Each community Dr. M. Hemam is with the ICOSI Laboratory, University of Khenchela, 40000 Algeria. (corresponding author to provide phone: +213 21-91-23-23; fax: +213 21-91-17-17; e-mail: mounir.hemam@ gmail.com). Dr. M. Djezzar is with the Department of Computer Science Constantine 2 University, 25000 Algeria (e-mail: djezzar.meriem@gmail.com). Dr. T. Djouad is with the ICOSI Laboratory, University of Khenchela, 40000 Algeria. (e-mail: tarek.djouad@ gmail.com). has its own interests and perceives differently the conceptual entities of the same universe of discourse [3]. Most methods and methodologies of ontology construction do not deal with the variety of perceptions related to the same universe of discourse and offer tools and directives to create a single model for a single vision of the observed world. The viewpoint approach is opposed to this monolithic approach and makes it possible to model the same reality according to different points of view [2]. In this paper, we are interested in the problem of multi- representation in ontologies. We believe that the most appropriate way is to use viewpoint notion in order to build ontologies called "multi-viewpoints ontologies". The latter is defined in [3], [4] as an ontology which is used to group different possible conceptualizations of the domain modeled according to different perspectives in a single ontology The objective of this work is to present a method for building ontologies that take into account different view points of users. Thus, to attain this objective, our approach is as:  At the conceptual level, a multi-viewpoints ontological model is defined. The latter is based on ontology and viewpoint notions. Ontology represents domain knowledge shared by several actors and the viewpoint represents domain knowledge that is relevant and visible according to the perception of a single actor.  At the formal level and based on the multi-viewpoints ontological model, we use a sub-language of the DLs  [4] to express notions inherent to viewpoints such as global and local concepts, bridges, stamps, etc. The remainder of this paper is organized as follows. Section II briefly summarises the multi-representation paradigm based on stamping mechanism. Section III provides an overview of the multi-viewpoints approach. In Section IV we present our approach for building multi-viewpoints ontologies. Finally, Section V concludes this paper. II. MULTI-REPRESENTATION BASED ON STAMPING MECHANISM The multi representation problem is commonly known in the discipline of information modelling. In databases field, many works address specific facets of multi-representation.. The work presented in [6] has investigated the problem and proposed an extension of existing ER-based model. Hence, a stamping mechanism of data elements (concepts, attributes, instances) and relationships is suggested to enable manipulations of data elements from several representations. A DLs stamping technique has been studied in [7], respecting the preceding characteristics, to allow multiple A Description Logics Based Approach for Building Multi-Viewpoints Ontologies M. Hemam, M. Djezzar, T. Djouad I World Academy of Science, Engineering and Technology International Journal of Computer and Information Engineering Vol:10, No:12, 2016 2111 International Scholarly and Scientific Research & Innovation 10(12) 2016 scholar.waset.org/1307-6892/10006209 International Science Index, Computer and Information Engineering Vol:10, No:12, 2016 waset.org/Publication/10006209