The global objective of the Problem Ontology Description is to provide an overview of the problem domain. Stakeholders naturally express requirements in their own terms and with implicit knowledge of their own works [1]. Therefore the aim of this activity is deepening the understanding of the problem by complementing the usual requirements description in terms of use cases with a description of the concepts that compose the problem domain. It describes concepts used in the specific language of the application domain and users. Results of this work can sometime imply modifications in uses cases. The design of the domain ontology occurs very earlier in our methodological process and this has a direct consequence in the organization and capacity identification activities. Problem ontology is modeled by using a class diagram where concepts, predicates and actions are identified by specific stereotypes.
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Goal
The global objective of Domain Ontology Description is to provide an overview of the application’s context. Stakeholders naturally express requirements in their own terms and with implicit knowledge of their own work. So the aim is deepening the understanding of the problem by complementing the usual requirements description in terms of use cases with a description of the concepts that compose the problem domain. It describes concepts used in the specific language of the application domain and users. This can thus sometimes imply modifications in uses cases. The design of the domain ontology occurs very earlier in our methodological process. That denotes the substantial role played by ontology in our process, and especially in organization identification and capacity identification activities.
Input
The problem’s ontology is deduced from a set of text descriptions of the system usage scenarios, from interviews of stakeholders and “experts” of the domain, and from the previously identified requirements.
Output
The ontology is described in terms of concepts, predicates, actions and their relationships.
MAS Meta-Model Elements
Define(Ontology), Define(Concept), Define(Action), Define(Predicate), Relate(Concept, Concept), Relate(Action, Concept), Relate( Predicate, Concept).
Methodological Guidelines
Use Cases and the inputs of DRD activity constitute the starting point for the ontology description. The concepts identification is the first step. It can be done by looking into use cases description to find recurrent nouns.
When major concepts have been identified, two means are available to determine
their relations. The first is looking into existing and well known ontologies
to determine if a match is possible. The second is interviewing domain experts and
looking into the textual description of usage scenario and other available documentation.
Suggested notation
An UML profile for class diagram is used to describe ontology. Table 1 details the mapping between ASPECS meta-model and UML construct used to describe ontologies. This diagram represents an XML schema that can be used to obtain a Resource Description Framework (RDF) encoding of the ontological structure.
| ASPECS Item | UML Construct | UML Stereotype |
|---|---|---|
| Concept | Class | concept |
| Predicate | Class | predicate |
| Action | Class | action |
| Ontology | Package | ontology |
References
- [1] Software Engineering
- I. Sommerville.
International Computer Science Series. Addison Wesley, Pearson Education, seventh edition edition, 2004.
ISBN: 0- 321-21026-3.
