What is Metamorphosis

Topic Maps

Metamorphosis' Architecture










Daily, a lot of data is produced by every institution or company. To satisfy the storage requirements, these organizations use most of the times relational databases, which are quite efficient to save and to manipulate structured data. Unstructured data (appearing inside documents) is stored in plain or annotated text files.

There is a problem when these organizations require an integrated view of their heterogeneous information systems. It is necessary to query/exploit every data source, but the access to each information system is different. In this situation, there is a need for an approach that extracts the information from those resources and fuses it.

Topic Maps are a good solution to organize concepts, and the relationships between those concepts, because they follow a standard notation -- ISO/IEC 13250 -- for interchangeable knowledge representation. Topic Maps are composed of topics and associations giving rise to structured semantic network that gathers information concerned with certain domain. This hierarchical topic network can represent an ontology. This is the reason why we are using successfully, for some years, this technology for classification and integration of documents in the area of digital archiving.

However, the process of ontology development based on topic maps is complex, time consuming, and it requires a lot of human and financial resources, because they can have a lot of topics and associations, and the number of resources can be very large.

To overcome this problem, Metamorphosis  was proposed. Metamorphosis  make possible the Topic Maps extraction, validation, storage, and browsing. It is composed of three main modules: (1) Oveia extracts data, from heterogeneous information systems, according to an ontology specification, and stores it in a topic map; (2) XTche validates the generated topic map, according to a constraint specification; (3) Ulisses browses the topic map, giving a conceptual view over the resources.

This way, Metamorphosis let us achieve the semantic interoperability in heterogeneous information systems because the relevant data, according to the desired information defined in an ontology specification, is extracted and stored in a topic map. The environment validates this generated topic map against a set of rules defined in a constraint language. That topic map provides information fragments (the data itself) linked by specific relation to concepts at different levels of abstraction. Moreover, the navigation over the topic map is led by a semantic network and provides an homogeneous view over the resources -- this justifies our decision of call it semantic interoperability.

Enabling to create a virtual map of information, the information systems are kept in their original form, they are not changed. Then, the same resource can be used by Metamorphosis  in different ways, for different topic maps. As it is possible and easy to change the map itself, data reuse is achieved. 


Departamento de Informática - Campus de Gualtar
4710-057 Braga - Portugal
Tel.: +351 253604470 Fax : +351 253604471