Problem Ontology Description
The problem’s ontology is deduced from the text descriptions of system usage scenarios, from interviews to stakeholders and domain experts, and from the previously identified requirements.
The ontology is described in terms of concepts (categories, entities of the domain), predicates (assertions on concepts properties), actions (performed in the domain, and affecting the status of concepts) and their relationships. An profile for UML class diagrams is used to describe the ontology. Table 1 details mapping between ASPECS metamodel and UML constructs used to describe ontology. This diagram can be translated into an XML schema that can be used to obtain a Resource Description Framework (RDF4) encoding of the ontological structure.
|ASPECS Item ||UML Construct ||UML Stereotype |
|Concept ||Class ||concept |
|Predicate ||Class ||predicate |
|Action ||Class ||action |
|Ontology ||Package ||ontology |
|Table 1: UML Profile Detail for Ontology Description |
MAS Metamodel Elements
Define(Ontology), Define(Concept), Define(Action), Define(Predicate), Relate(Concept, Concept), Relate(Action, Concept), Relate(Predicate, Concept).
Work to be done & Methodological guidelines
The first task in the ontology description, aims at identifying major concepts. It can be done by looking at use cases (textual) description to find recurrent nouns. These concepts are then arranged by means of inheritance and abstraction. New higher level concepts will be so identified. When major concepts have been identified, the third task consists in determining concepts relationships and especially composition ones. There are two ways available to determine these relations. The first consists in looking into existing and well known ontologies to determine if a reuse is possible. The second is interviewing domain experts and looking into the textual description of usage scenario and other available documentation (see subsection 4.4).
The ontology associated to the domain of the FIRA Robot soccer is partially detailed in figure 6. This ontology represents knowledge about robot soccer matches such as how time periods are handled, the different mobile (and thus situated) elements, rules handling, etc.
|Figure 6: Ontology of the problem domain associated to FIRA Robot soccer |