Constraint-based representation and reasoning for computer-aided design /
Design can be considered as a constraint satisfaction
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| Format: | Thesis Book |
| Language: | English |
| Published: |
[Place of publication not identified] :
[publisher not identified] ;
1995.
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| Subjects: | |
| Online Access: | Link to OAKTrust copy http://proxy.library.tamu.edu/login?url=http://proquest.umi.com/pqdweb?did=742745811&sid=1&Fmt=2&clientId=2945&RQT=309&VName=PQD |
| Summary: | Design can be considered as a constraint satisfaction problem. The process of designing mechanisms, usually including conceptual and detail design stages, can be viewed as establishing and maintaining design constraints. Conventional computeraided design systems are effective for the later stage of detail design, but provide less support for conceptual design. An adequate and unified scheme for representing and satisfying constraints through different design stages is the most essential part of a truly effective design system. This dissertation presents such a scheme as the basic framework of a constraint-based design system. A constraint-based and object-oriented representation is proposed to represent geometric structures which allow incompletely specified geometric information. This representation defines all geometric information as constraint objects and maintains a constraint hierarchy and dependency hierarchies for the automated reasoning process. Constraint networks are generated by instantiation and unification of geometric constraints to represent geometric models. Geometric constraints are satisfied incrementally by a general reasoning scheme to create a new design when existing constraints are changed or new constraints are generated. The reasoning scheme is a combination of value propagation and constraint activation techniques for constraint satisfaction. The propagation process is performed through propagation methods along with sets of propagation rules. Each set of the propagation rules is defined for a particular class of constraints. Heuristic functions are introduced to improve the performance of the propagation process. An experimental 2D constraint-based design system is implemented based on the proposed reasoning framework. Various simple two-dimensional design examples are shown to demonstrate different functions of the design system. Although this dissertation focuses on the representation and automated reasoning of geometric constraints, a method for using the same framework to combine functional design with geometric design is also discussed. |
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| Item Description: | Vita. "Major Subject: Computer Science". |
| Physical Description: | xi, 113 leaves : illustrations ; 28 cm. Issued also on microfiche from University Microfilms Inc. |
| Bibliography: | Includes bibliographical references. |