Knowledge structuring & Problem-solving issues
Class 1 Design:
Class 2 Design:
...use of generalized (standard) plans to produce new models
...innovations possible with respect to components
Class 3 Design:
...alternatives to well-established design - changes with respect to specifications not components
e.g. house building
Distinctions between these classes are not clear... merging ... no clear delineation
Note: compare design and planning
Is this task trivial or complex?
Changes ... repercussions
Routine vs. open-ended
Complexity of the task arises from:
DSPL: Design Specialists & Plans Language
(database: Materials and Parts & Structure)
Organization of Knowledge:
eg. SmallTableDesigner / \ / \ TopDesigner SupportDesigner (pg. 5)The design process starts at SmallTableDesigner, at the point where the overall requirements are given to the design system. Consider the case in which SmallTableDesigner chooses its first plan, calls TopDesigner, which in turn chooses its first plan, does the design of the Top, and returns the dimensions to its parent. Now SmallTableDesigner calls SupportDesigner. Suppose that this specialist's only plan fails to generate a successful design within the constraints; i.e., the strength requirement and dimension constraints are not reconcilable. This would cause "failure" to be returned to SmallTableDesign.
SmallTableDesigner then calls TopDesign again with a further constraint about the weight that is permitted. Now TopDesign will invoke its second plan (which is the more expensive plan to execute), and some info about the Top design is passed to SupportDesigner through its parent SmallTableDesigner, causing SupportDesign to succeed, and the design to succeed.
While plans are "pre-compiled", actual designs are not - they are actually generated during problem-solving.
check requirements for consistency
... is full design worth pursuing
Considerations - necessary knowledge - organization of knowledge
- Redesign: alternatives of existing design due to establishment of new specifications. Keep as much as possible of the old design - concentrate on changing whatever is necessary to fix the problem
The selection process:
1) recommendation of candidate plans (Sponsors)
Plan ... result of past planning by human designer
By selecting a plan - specialist is refining the plan that calls it.
eg. Selector / | \ / | \ Sponsor Sponsor Sponsor | | | | | | Plan1 Plan2 Plan3
E.g. Plan in Specialist S0 : < S1 ; T1 ; S2 >
eg. < S1 ; T1 ; S2 > /\ /\ / \ / \ / \ / \ < T2;T3 > < S3;T4 > /\ / \ / \ < T5;T6 >
This plan has been selected by specialist S0...
is being refined by specialists S1 & S2
S3 refines plan in S2