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Title: Reuse of knowledge bases & problem solvers explored in the VT domain
Author: Runcie, Trevor John
ISNI:       0000 0001 3539 655X
Awarding Body: University of Aberdeen
Current Institution: University of Aberdeen
Date of Award: 2008
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This thesis explores the reuse of knowledge bases through semi-automated code generation of new KBs and explores the issues surrounding the use of constraint satisfaction techniques to solve the Sisyphus II VT challenge and the related class of problems.  For my primary analysis I chose a knowledge base system written in CLIPS which was based on the propose-and-revise (PnR) problem solver, and which had a lift/elevator knowledge base (KB).  Components were initially extracted manually, and then semi-automatically, and were used with both an Excel spreadsheet and a constraint problem solver (ECLiPSe) to solve a range of tasks.  I have produced a reuse system which is useable by domain experts. The next phase was to implement ExtrAKTor which extracts the same 4 knowledge sources virtually automatically from the CLIPS knowledge base (held by Protégé), and to transform these so that they are compatible with additional problem solvers.  To date Excel & ECLiPSe have been used, and again it has been demonstrated that the resulting systems are able to solve lift configuration tasks.  This work has produced a reuse system which is useable by domain experts.  The ExtrAKTor system has been independently tested using an enhanced version of the U-HAUL KB; a KB in the removal truck rental domain. Fixes are an essential part of P&P.  Using the tightly constrained VT KB generated by ExtrAKTor from the original Protégé KB, ECLiPSe did not require fix information to find a solution.  The decision was made to create a less tightly constrained version of the KB to more fully investigate the solution space and determine if fix information could be encoded and used effectively in a CSP environment.  It became apparent that performance was significantly affected by ordering of clauses due to Prolog’s backtracking during component selection; this had not been an issue with the more tightly constrained KB.  The ExtrAKTor code was then further refined adding the “domain” and “infers most” construct which led to a substantial performance improvement largely independent of clause ordering.  The conclusion of the experimentation is that ECLiPSe does not require expert provided fix information to efficiently solve the VT class of parametric design problems.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available