Process Architecture Study: Documentation
Reviews
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All elaborated documents were later handed over to two independent reviewers in order to examine the three solutions. This was done in an attempt to acheive a more objective evaluation of the produced solutions.

As described in a previous chapter the documents were reviewed by two reviewers who both hold a associate professor position at the university. They were both given half an hour to examine the three documents and then afterwards they were to give an oral evaluation which also lasted half an hour. The oral evaluation was recorded with a dictaphone. The following two sections are transcripts of the evaluations with the two reviewers.

The First Review

The first evaluation was performed by an associate professor from the research group of the formal sematics. The general impressions of his evaluation can be summerized in the following: First, the object-oriented paradigm is primarly focussing on data structures described by the objects. According to reviewer R1 the advantage achieved here is that one can quickly turn from specifying the design to actual coding the implementation. However, he also stresses that it would be difficult to verify the requirements stated in the problem statement with this approach.

The two other paradigms are characterized be the fact that they are focussing on aspects of synchronization identified in the problem. Reviewer R1 is of the opinion that this is very useful when avoiding dangerous situations where the system does not embody the right kind of behaviour. However, these two solutions also reflect great complexity and according to reviewer R1, this cannot be avoided even though you use automated machinery during the design process. In fact, he is the opinion that the lift control problem would probably explode in complexity due to the numbers of actions in a final, complete solution. Hence, it would be very difficult to solve the task when only using one of these two paradigms.

At the more general level, reviewer R1 stresses that all three solutions are lacking a more abstract design strategy in order to outline the requirements to the system. This has not be done in any of the three solutions. On the contrary, all three solutions reflect much more specific design where the lower level components have been identified and specified.

As a final evaluation of the solutions reviewer R1 says that it is difficult to compare the three solutions due to their very different approaches. He states, however, that all solutions show a fair degree of being useful if they should have continued with the design and implementation phases. So marking the solutions with grades he would give them the following:

The Object-Oriented Solution: Good
The Operating Systems Solution: Good
The Mathematical-Logical Solution: Good

The Second Review

The second evaluation was performed by an associate professor from the research group of programming systems. His general impressions can be listed as follows: Reviewer R2 states that the object-oriented solution at first hand attracts him at most. This is mainly due to fact that the use of objects are well-suited for identifying real world entities such as the elevators, the floors etc. He is aware of that it might be difficult to verify that the object-oriented solution shows the right kind of behaviour. He is, however, quite certain that it would be possible to incorporate some invariants, but he also stresses that it could not be done in an as elegant maner as the two other paradigms.

He stresses that the operating systems and the mathematical-logical paradigms are very complex and enormous:
It easily becomes signs and strange actions, where you cannot associate anything with these widgets. A semantic gap is introduced between your intuitive understanding of the problem and the actions in the paradigm.
Generally, he finds all three solutions incomplete. Actually he is of the opinion that one cannot consider them as being finished. In addition, he feels that they are enormous. He more considers the solutions as partial solutions inspired by the rules in the problem statement. As far as he can see none of the three designers have verified whether the six rules are consistent or not, or whether there are some unclarified questions hidden in the problem statement. He is, however, uncertain how the task could have been approached at a higher level. In fact, he admits that he would probably have done in the same way if he had been confronted with this particular task.

On the question of rading the solutions he says that he find all solution average. He marked the solutions as follows:

The Object-Oriented Solution: Average
The Operating Systems Solution: Just below average
The Mathematical-Logical Solution: Just below average