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

14 CHAPTER 2. PROBLEM SETTING
2.2.2 Modeling language, meta-model and model semantics
Any model must be built in a certain modeling language. A modeling language is any
artificial language that can be used to express information or knowledge or systems in
a structure that is defined by a consistent set of rules. A modeling language is used
to represents concepts and relationships and other phenomena with a set of graphical
notations or symbols. Such a modeling language is often called graphical modeling
language. ER [15], UML [125], BPMN [12], EPC [160] are examples of graphical
modeling languages. A modeling language can also be a set of standardized textual
keywords or markup language accompanied by parameters, for instance, OWL [195],
BPML [11], BPEL4WS [116], and EPML [105]. Graphical modeling languages usually
facilitate readability of models whilst textual modeling languages enable models
machine-interpretable and tool-interchangeable.
Interpretations of the meaning of modeling components in a modeling language are
generally defined in a meta-model. A modeling components such as a graphical notation
or a symbol and a textual keyword or a markup label is called a meta-model element or
a modeling construct in our work. Meta-model elements defined in a meta-model are
the building bricks of a model. A meta-model is also a model of a domain of interest
and it is an instance of a meta-meta-model. A model in a certain modeling language
is the instance of the meta-model of this modeling language. A model having all the
instances of user objects is the instance of model. Instantiated model, model, metamodel
and meta-meta-model respectively correspond to the M0, M1, M2 and M3 layers
of OMG’s four layer meta-data architectures [124].
In this thesis, meta-meta-model is beyond our research focus. While, instantiated
model at the M0 layer is too specific to be reused. We therefore mainly focus on M1
and M2 layers, i.e. model and meta-model.
Common uses of meta-models are as follows [207]:
• As a schema for semantic data that needs to be exchanged or stored.
• As a language that supports a particular method or process.
• As a language to express additional semantics of existing information.
The three usages of meta-models are all employed in the thesis. The meta-model of
a business process model supports process modeling. It is also stored as a schema
associated with a model file. Facilitating the exchange of different process models is
one of our research goals so that meta-model is one of our research objects. Establishing
a semantic annotation method itself is a process of creating a meta-model to specify
the additional semantics of an existing model.
The term semantics in linguistics means the study or science of meaning in language,
or the study of relationships between signs and symbols and what they represent. It
also indicates the meaning or the interpretation of a word, sentence, or other language
form [3]. Model semantics is hereby the meaning or the interpretation of a model. Model
semantics are represented by model elements. Model elements are the components of a
model. Interpretation of model elements usually depends on the context of the system
which the models represent the solutions for. Besides, model elements are composed
of modeling constructs, and the semantics of modeling constructs are defined in a