Model-Driven Engineering - Model-Driven and Software Product Line Engineering - page 59

Amodelhasbeenusuallyreferredtoinsoftwareengineering
as an artifact built by using a modeling language (e.g.
UML). Stachowiak [STA 73] describes the model concept
more precisely by presenting three criteria, which were also
discussed by Kuhne [KÜH 05]:
- Mapping . A model represents a mapping between some
part of the reality and the set of elements forming the model ;
- Reduction . A model only reflects a (relevant) selection of the
original's properties ;
- Pragmatic . A model needs to be usable in place of the
original with respect to some purpose.
A model is specified in some modeling language. Modeling
languages are usually called domain specific modeling
languages (DSML) because they are tailored to certain
concernsofspecificdomains,whichmakethemeasiertospecify,
understand, and maintain than general-purpose modeling
languages. DSMLs tend to support high-level abstractions,
which are closer to the problem domain than to the
implementation domain.
A DSML is either visual or textual and involves at least
four aspects: (1) a notation for the construction of models,
which is defined by a concrete syntax , (2) a description of the
vocabulary (concepts, relationships, and integrity constraints)
of the domain concepts, which is defined by an abstract
syntax ,(3) mappings between abstract and concrete syntax ,and
(4) the way to use the domain concepts to create well-formed
models,which is defined by the semantic domain .The semantic
domain is usually defined by means of some mathematical
formalism in terms of which the meaning of the models is
explained [EME 04]. This is a form of static semantics for
models. The dynamic semantic is a more difficult thing to
express; formal or mathematical notations are required. In
the context of UML and MDE, it is often defined using OCL
expressions, see section 3.3.