Usage > Introduction
Computer-based models can be technically seen as files. The main functionality of this collaboration platform is the management of metadata and semantic information about these files in a catalogue-oriented structure.
The approach of our platform is, that the structure of the catalogue is defined using ontologies. The rationale is that for each specific application domain a specific ontology could exist. Thus the implementation of the collaboration platform remains independent. This model must therefore describe the domain-specific kinds of models and their relations. In the project RDF and RDF Schema (RDFS) were chosen as language standards for modelling the catalogue structure in ontologies. During the specifications process the project has performed an evaluation about a selection of modelling languages and found, that RDFS represents a sound mix taking maturity, expressiveness, simplicity and community adoption into account. RDFS is a standard for the description of metadata and maintained by the W3C Semantic Web activity group. The Semantic Web activity group sees this language as one of the foundations to describe data and documents available in the WWW to make the information in the WWW process-able by software-systems.
Ontologies and Catalogues The general relation between an abstract catalogue and the RDFS-based ontology is very straight forward. On one side we have the structure of a catalogue categories and their entries. An entry represents the set of metadata. And on the RDFS-side we have represented the categories through concepts, which are in RDFS-terminology classes. Attributes are defined for each concept, which represent the attributes for each of the instances.
Each time an entry is created, this results in a new instance in the ontology. The framework supports the evolution of the ontology to alter the structure of the catalogue during run-time. Apart from the structure the ontology changes heavily during run-time, because entries in the catalogue are created as instances of concepts right in the model. This means that all the metadata of the catalogue is placed also in the model.
In beginning, at the deployment of the platform to create a catalogue, so-called schema ontology is needed, which defines the domain-specific structure of the catalogue. We propose to create this ontology with one of the many available modelling tools for RDF models like Protégé, OILed, or the KAON OI Modeller. Currently, we do not attempt to deliver a functionality to create schema ontologies as the description of the catalogue structure in our framework, because the already present tools are highly developed. In summary the main rationale is to develop a principle, that manages the catalogue using an RDFS-based model. Since we have used the KAON framework as the API and persistence solution for RDFS-ontologies in our framework, in this context such ontology is called Ontology-Instance-Model, short OIModel
