A Triptych Software Development Paradigm - Correct System Design: Recent Insights and Advances - page 38

4.8 Sustainable Development

Sustainable development is now the act of actually carrying out the planned
development after analysis of plans has validated these according to desired
equities.

type
Development = (Plan RS)

! RS

Here we have taken a very simplistic view of development. A more realistic view
would only add details and not further illustrate the formalisation principles we
strive to adhere to.

4.9 Time Frames

Among the resources treated is time. In the RAIs arguments there will undoubt-
edly be various forms of time attributes and indicators: past, present and future
time, time intervals, etc. Non-time attribute indicators may themselves be func-
tions of times and intervals.
Thus we believe, that in the above model we capture \all" conceivable needs
for time parameters, time considerations, etc.

4.10 Discussion

Resources vs. Resource Representations: As always our language of communica-
tion, in the daily pursuit of our business: here sustainable development, mixes
references to \real" resources with references to representations of resources. As
long as we are fully aware of the dangers in possibly confusing them, OK. So far
we have been referring to \real" resources, not their representation. That will
be done in Section 5.1.

Function Arguments and Results: In this paper we \lump" all conceivable argu-
ments to functions and predicates into the convenient form of one single rais:RAIs
argument.
Readers may nd that when they start understanding what all these func-
tions, like Equity \predicates", Experimental Analysis and Analysis functions,
Planning and Development functions, are doing, then they may start wondering:
what happened to time considerations?; what happened to nancial expendi-
tures, what happened to the deployment of engineers, designers, construction
workers, etc.?
The simple answer is: They are all gathered together, not as separate param-
eters to conventionally type functions, as in mathematics or programming, but
as a rais:RAIs argument.
Let us just show an example:

Examples 5 A `before'/`after' development relation: