Evaluation of Structure Charts:- In the evaluation of structure charts, we are concerned with two issues: (a) How to represent a structure chart (b) How to formalize the criteria for evaluating the chart. The first issue is a study of the knowledge representation. The second issue is slightly more complex because most of the criteria suggested in the literature are rather vague and imprecise. Representation of Structure Charts:- We need to know (a) All the modules in the chart (b) All the data items in the chart (c) The organization of the modules (d) All the communications among modules. As an example-2 for illustration, consider Figure -2. It shows part of an interactive system for updating a file. First of all, we identify all the modules in the system by defining the is_module predicate: • is_module (updateFile). • is_module (getValidTrans). • is_module (getTrans). • is_module (validateTrans). • is_module (getMaster). • …….. Second of all the data items through the is_datapredicate : • 1st argument of is_data is the name of a data item • 2nd argument is a simple item (atomic), a composite item (record) or a flag (control). • is_data (trans, record). • is_data (validTrans, record). • is_data (continueResponse, control). • ... Third of the Organization of the modules • The predicate structure (ParentModule, Type, ChildModules) describes the connection between a Parent Module and a list of Child Modules • Type of connection which are denoted by the constants seq, sel or itr respectively. • structure (updateFile, itr, [getValidTrans, getMaster, updateMaster, putNewMaster]). • structure (getValidTrans, seq, [getTrans, validateTrans] ). • structure (putNewMaster, seq, [formatMaster, writeMaster, askIfUserWantsToContinue] ). Finally, we specify the communication between modules. • The predicate coupling (Data, Source Module, Target Module) • coupling (validTrans, getValidTrans, updateFile). • coupling (trans, getTrans, getValidTrans). • coupling (validTrans, validateTrans, getValidTrans).
Posted on: Sun, 30 Jun 2013 23:51:55 +0000
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