Unifying multilevel modelling through ontologies

In the last decades, the multilevel problem has received increasing attention in the conceptual modelling and semantic web communities. Recently, we proposed a solution to this problem in the context of ontological modelling which consists in extending the Web Ontology Language OWL with a new multilevel constructor that equates instances to classes. In this work we highlight the advantages of exploiting the reasoning capabilities of OWL ontologies with the proposed multilevel constructor by analizing requirements from a real-world application on the accounting domain

Design and foundations of ontologies with meta-modelling.

Ontologies are broadly used and proved modelling artifacts to conceptualize a domain. In particular the W3C standard ontology language OWL, based on description logics, allows the ontology engineer to formally represent a domain as a set of assertions about concepts, individuals and roles. Nowadays, complex applications leads to combine autonomously built ontologies into ontology networks by relating them through di erent kind of relations. Some relations, such as the mapping of two concepts from di erent ontologies, can be expressed by the standard ontology language OWL, i.e. by the description logics behind it. However, there are other kind of relations that are not soundly represented by OWL, such as the meta-modelling relation. The meta-modelling relation has to do with the modelling of the same real object with di erent abstraction levels, e.g. as a concept in one ontology and as an individual in another ontology. Even though there are a set of approaches that extend description logics to deal with meta-modelling, they do not solve relevant requirements of some real scenarios. The present thesis work introduces an extension to the description logic SHIQ which provides a exible syntax and a strong semantics, and moreover ensures the well-foundedness of the interpretation domain. This approach is di erent from existing meta-modelling approaches either in the syntax or in the semantics (or both), and moreover ensures the well-foundedness of the domain which is an original contribution from the theoretical point of view. The meta-modelling extension of SHIQ introduced in the present work is justi ed by a detailed description of a set of real case studies, with an analysis of the bene ts of the new approach to solve some relevant requirements. Finally, the present work addresses the methodological issue by introducing a design pattern to help the ontology engineer in the use of the proposed meta-modelling approach

Metaquerying made practical for OWL 2 QL ontologies

Metamodeling and metaquerying are gaining momentum in the context of both conceptual modeling and semantic web. Indeed it has been largely recognized that metamodeling represents a very useful tool to formalize complex patterns involving elements of the domain of interest, that otherwise are forced to be excluded from the modeling process, and a number of languages equipped with a spectrum of metamodeling features have been studied. However, it has been recognized as well, that the benefit of using metamodeling is greatly limited if one cannot use metaquerying as tool for extracting knowledge deriving from such meta-level patterns. Unfortunately, at the moment, no system exists that correctly manages metamodeling and metaquerying. The goal of this work is precisely to fill this gap by introducing a system, called MQ-Mastro, that allows metaquerying over ontologies expressed in a language of the OWL 2 family equipped with a semantics appropriate for metamodeling