| Project/Area Number |
63880005
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| Research Category |
Grant-in-Aid for Developmental Scientific Research (B).
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| Allocation Type | Single-year Grants |
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| Research Field |
Informatics
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| Research Institution | Hokkaido University |
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Principal Investigator |
AKAMA Kiyoshi Fac. of Engineering, Hokkaido Univ., Associate Professor, 工学部, 助教授 (50126265)
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| Co-Investigator(Kenkyū-buntansha) |
UNEMI Tatsuo Department of Planning and Management Science Nagaoka University of Technology,, 計画経営系, 講師 (50151915)
TKIGAWA Tetsuo Fac. of Letters, Hokkaido Univ., Associate Professor, 文学部, 助教授 (30098503)
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| Project Period (FY) |
1988 – 1989
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| Project Status |
Completed (Fiscal Year 1990)
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| Budget Amount *help |
¥3,200,000 (Direct Cost: ¥3,200,000)
Fiscal Year 1989: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1988: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | Class bound variable / Typed prolog / Inheritance hierarchy / Variable with constraint / Multiple inheritance / Logic programming / Constraint logic programming / 知識表現 / 論理型言語 / 集合束縛変数 / 黒板 / 最良優先探索 / 自然言語処理 / 仮説推論 |
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| Research Abstract |
In this research we have constructed a knowledge representation system PAL89 which is an extention of pa186, that is, an extended prolog to deal with inheritance hierarchy which is a tree structure formed by the inclusion relation among classes and instances. Pa186 adopts class bound variables (CBVs), which are variables with class constraints. CBVs improve the inferential efficiency greatly by suppressing unnecessary backtracking and exhaustive searches.
The characteristics of PAL89 include
1. Extended functions of CBVs. (1) Variables can have any constraints which are computed by set operations (difference, union and intersection), which enables the system to provide declarative multiple inheritance representation. (2) A inheritance hierarchy compiler and inheritance hierarchy clause indexing are implemented, which makes the system faster.
2. Typed cons patterns. AII objects used in PAL89 can have types. So PAL89 can be regarded as a typed prolog. Types play an important role in partial evaluation, learning and automatic program generation.
3. Variables with constraints. Users can introduce new classes of variables with constraints and their unification. Therefore the user can define new objects by variables with constraints and can represent relations between them. This leads us to the concept of "DUAL PROGRAMMING", that is, two step Programming whose first step is defining objects and second step is defining relations.
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