90-754 Homework #5: Criteria and Comments
7 April 1999 
A sample solution to Problems 9.3a-f are provided here.

Overall criteria for the individual assignment:
Score Description
10 Grasp of the core concepts demonstrated, and rationale for decisions explained
9 Mostly complete, but made some nominally incorrect assessments of the strengths of various architectures and design choices
8 Attempted, but lacked sufficient explanation of design choices, or parts of the assignment were incomplete.
0 No attempt made

Problem #9.3a
Problem #9.3b
Problem #9.3c
Problem #9.3d
Problem #9.3e
Problem #9.3f

Problem 9.3a: Assigning weights to design points

Number Description
1.1 Your explanations are a bit brief; we were hoping that your explanations would reflect deeper insight into these system design concerns.
1.2 "Maintenance" may also include adding new drugs or other information to the system; this will be a major concern as well.
1.3 "Legal Compliance" refers to the support your system offers for abiding the complicated FDA controlled substances schedule; pharmacies that violate these laws even once could lose their license to operate.  Therefore, we expected that you would consider it a high priority to help your client follow the law.
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Problem 9.3b: Rating characteristics of 3 architectures

Number Description
2.1 Accuracy will probably be worse for local, decentralized systems, because ensuring that the data on a particular local machine is up to date is hard.  Centralized systems always have up-to-the-minute information, since data only exists in one place.
2.2 Maintaining the data store will be easier for centralized systems, since data must only be changed in a single place.  Local systems might require a CD distribution, a manual download, or on-site service to change their data.
2.3 You needed to explain how you arrived at the ratings for the various architectures.
2.4 It is generally accepted that local, stand-alone systems will have better response time from user requests because no network transactions are involved.  Thus, locally oriented systems will tend to have better performance that network-based systems.
2.5 It is easier to develop a system that stands alone on one machine than one that runs over a distributed network.  So, development ratings should be higher for the local system than for the distributed architectures.
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Problem 9.3c: Choosing a control type
Number Description
3.1 Declarative control is really only used in interactive intelligent or expert systems such as exploratory learning environments or logic programming environments.  You are not likely to ever encounter a need for a declarative interaction style in your career.  An event driven model is more appropriate for this problem.

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Problem 9.3d: Choosing a data management approach
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Problem 9.3e: Choosing a database management paradigm
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Problem 9.3f: Choosing a data interaction strategy

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