| Project/Area Number |
10680341
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
計算機科学
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| Research Institution | The University of Electro-Communications |
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Principal Investigator |
KASAI Takumi The University of Electro-Communications, Faculty of Electro-Communications, Professor, 電気通信学部, 教授 (70027382)
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| Co-Investigator(Kenkyū-buntansha) |
HASUNUMA Toru The University of Electro-Communications, Faculty of Electro-Communications, Research Assistant, 電気通信学部, 助手 (30313406)
TAKENAGA Yasuhiko The University of Electro-Communications, Faculty of Electro-Communications, Associate Professor, 電気通信学部, 助教授 (20236491)
IWATA Shigeki The University of Electro-Communications, Faculty of Electro-Communications, Professor, 電気通信学部, 教授 (80102028)
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| Project Period (FY) |
1998 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥2,400,000 (Direct Cost: ¥2,400,000)
Fiscal Year 2001: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2000: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1999: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1998: ¥700,000 (Direct Cost: ¥700,000)
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| Keywords | Formal Languages / Automata / Tree Automata / Complexity / TAG / Natural Languages / Context-Free / 文脈自由木オート・マトン / プッシュダウンオートマトン / プッシュダウン木オートマトン / プシュダウン木オートマトン / プッシュダウン・木オートマトン |
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| Research Abstract |
We introduced a restricted model of context-free tree grammars called spine grammars, and studied their formal properties including considerably simple normal forms. Recent research on natural languages has suggested that formalisms for natural languages need to generate a slightly larger class of languages than context-free grammars, and for that reason tree adjoining grammars have been widely studied relating them to natural languages. It was shown that the class of string languages generated by spine grammars coincides with that of tree adjoining grammars. We also introduced acceptors called linear pushdown tree automatas are obtained from pushdown tree automata with restriction on duplicability for the pushdown stacks. We also investigated learning theory and obtained a polynomial time inference algorithm for Moore type sequential machines. Further we also investigated the automata models for tree adjoining grammars and introduced a model called transfer pushdown automata.
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