When Traditional Ontologies are not Enough: Modelling and Visualizing Dynamic Ontologies in Semantic-Based Access to Texts

The work described in this paper came about as a result of reflections made within the "Clavius on the web" Project, which studied the correspondence between the Jesuit mathematician and also astronomer and some important scientists of his century, such as Galileo and Brahe. One of the main aims of the project is to make it possible for students and scholars to access the texts on a semantic basis, in order to allow a deeper understanding of the often complex content, they convey. Texts are often the unique source that scholars have at their disposal in order to be able to reconstruct and more completely understand the past author's thought. In order for technology to come to the aid of scholars in this effort, the concepts evoked within the text, as well as the terms representing these concepts need to 1) have a structured organization 2) be explicitly and univocally represented and 3) be defined through the relationships that unite them. In order to achieve this, we chose to adopt an ontology based model, as ontologies are a de facto standard for knowledge representation. Interestingly, the choice to use ontologies raised some issues, also with regard to theoretical aspects: indeed, standard ontological formalisms usually static and crisp proved to be inadequate in modelling the complexity of the knowledge conveyed by the analysed texts. As a result, more refined models as well as appropriate graphical representations needed to be introduced so that computers would be able to process these ontologies and visualize them in a way that students and scholars could understand and work with them.