Semantic Annotation for Process Models: - Department of Computer ...

86 CHAPTER 5. GOAL ANNOTATION
in a relatively general sense (e.g. security goal) or in a specific way (e.g. safe payment),
so the subsumption relationship should be supported. Relations between two goals
having the same or different effects can be regarded as semantic equivalence or semantic
difference. Decomposition relation – an important characteristic found in most goal
analysis should be specified in the goal ontology too.
Based on the above analysis, semantics of goals in a goal ontology are specified
through categories, expression perspectives and relationships. OWL Classes and
Properties provide a way to define the semantics of goal concepts. Standing for
goal categories, Hard Goal and Soft Goal are two upper level classes for all goals in
general. Hard goals are functional and usually they are domain-dependent, so they
are usually specific from different domains. Soft goals can be described generally
in a set of "-ilities" (which are regarded as soft goal category), and also specific according
to domains. Attributes and relations of a goal class are represented through
owl:DatatypeProperty and owl:ObjectProperty respectively. Based on the analysis
of expression perspectives, we know that a goal can be represented through specifying
the targets such as Activity, Artifact, constraint and Actor-role. If those targets are
already defined in domain ontology as classes, a goal can establish relationships with
them. Otherwise, the goal uses attributes to represent them. To make the terminology
consistent (with GPO), we name the relations/attributes as targetActivity, targetArtifact,
targetRole and targetConstraint. State is modeled as an attribute of
Artifact, which is associated with the targetArtifact of a goal.
The subsumption relationship (owl:subClass) is used to represent goal hierarchy.
A simple part-whole relationship represent goal composition. OWL does not provide
any built-in primitives for part-whole relations (as it does for the subclass relation).
However OWL contains sufficient expressive power to capture most, but not all, of
the common cases [200]. We therefore apply a simple part-whole relationship to represent
the decomposition of goal concepts. The ’part’ goals contribute the impacts to
the ’whole’ goal. The logic connections (OR, AND, XOR) between the parts are not
considered in the goal ontology due to two reasons as follows. First, it is the representational
capability of OWL. Second, such concrete goal analysis mechanisms are not
necessary for a goal ontology. A goal ontology should be general to applications and
decomposition of a goal depends on a specific application. A goal ontology is more like a
taxonomy of goal concepts serving for semantically-aligned goal representation. Hence,
the terminology presenting goal concepts in a goal ontology should be normalized. In
addition, some general attributes such as ID, name, description are attached to a goal
class to identify a goal concept. Semantic representation of a goal ontology is specified
in the meta-model shown in Figure 5.1.
5.3 Relations between Process Models and a Goal Ontology
We can see that based on the design principles of a goal ontology modeling, underlying
relations between process models and a goal ontology becomes clear. These relations
can be used to derive goal annotation relationships of process models.
We start by clarifying some concepts involved in the relations. We assume that a