In this thesis, we propose an extension to the multiple-valued infinitesimal logic frame-work to provide a simple representation for prioritized constraints. We introduce two unary operators, ยต and w, to infinitesimal logic in order to define preferential constraints and backup constraints, respectively. The new framework naturally allows us to define a hierarchy of priorities among constraints. Also, we present a lazy algorithm for evaluating the multiple-valued prioritized constraint expressions of our representation. Our algorithm, which is similar to the alpha-beta pruning technique for minimax game tree evaluation, is based on a recursive depth-first traversal of the parse tree for the expression and works by evaluating operands within an increasingly narrower range of interest. Our implementation of this representation for querying a movies database demonstrates the expressive power and flexibility of our framework.
| Identifer | oai:union.ndltd.org:uvic.ca/oai:dspace.library.uvic.ca:1828/1833 |
| Date | 10 November 2009 |
| Creators | Agarwal, Ruchi |
| Contributors | Wadge, W. W. |
| Source Sets | University of Victoria |
| Language | English, English |
| Detected Language | English |
| Type | Thesis |
| Rights | Available to the World Wide Web |
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