Every specialist area has its own language for describing it, and the fact that some of these languages use very familiar terms does not make them less technical than a language structured entirely in a mathematical symbolism. This research aims to develop a language and to test this language. How can it be tested and what would constitute a validation of the work? In the review many such languages are encountered, each developed to solve a perceived problem with the (then) current state of conceptual modelling. There is an evident tension between semantically rich descriptions with a large number of different constructs which are not always easy to match to the real world, and semantically poor languages with a few constructs which mean that the modeller needs a lot of supplementary information to help understand the model.
Although it seems to have received little discussion, the implication is that there is
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Chapter 1Information from Data
an ideal modelling language which is not too poor to be able to represent the richness of a real world domain nor too rich to make the modelling process impossibly complex (figure 1.2). The author suspects that there is not such a language. The suitability depends not only on the richness and structure of the language but on the complexity of the real world domain, and the purpose of the modelling, and the experience of the players in the modelling process - the modeller and the user / client - will also moderate the success of a particular approach to conceptual modelling.
Difficulty
of
modeling
the DoD
Richness of the data modeling schema
Figure 1. 2 : Matching model to problem domain
It would be a very poor modelling method which could not be shown to be superior to all others for a particular problem description. Unfortunately, because of the high dimensionality of the real world, the success of problem domain modelling languages is not transitive and it does not follow that because A has been shown to be superior to B and B superior to C that A is any advance on C.
How then is it proposed to test the models developed in this thesis? The main requirement is consistency: that is, the language should be applicable in a consistent way without arbitrary treatment of particular situations. The language should be robust: that is, it should apply to situations for which it was not specifically intended. Thirdly the language should be parsimonious: that is, it should contain the minimum of constructs necessary to describe the domains for which it is intended. In this particular case robustness is of the essence, as it is intended to develop a modelling language which will not only represent in a satisfactory way the section of the real world being modelled, but also permit the
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