| Co-Investigator(Kenkyū-buntansha) |
MIWA Hiroyoshi NTT, Service Integration Research Laboratories, Chief Researcher, サービスインテグレーション研究所, 研究主任
ICHIKAWA Shuichi TOYOHASHI UNIVERSITY OF TECHNOLOGY, FACULTY OF ENGINEERING, Associate Professor, 工学部, 助教授 (70262855)
ITO Hiro TOYOHASHI UNIVERSITY OF TECHNOLOGY, FACULTY OF ENGINEERING, Lecturer, 工学部, 講師 (50283487)
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| Research Abstract |
A number of problems which have emerged due to the recent rapid progress of Internet, multimedia networks, mobile and wireless networks and computer technology have a discrete structure in nature. Thus we first formalize some of such problems as graph and/or network problems and tried to obtain efficient solution methods by elucidating their structural feature. As a result, efficient algorithms, either parallel or sequential, for Hamiltonian circuit problem on an in-tournament graph, two edge-disjoint paths problem on tournament graph, hinge vertex problem in an interval graph and a trapezoid graph were obtained in the field of network reliability. Moreover, some results on location problems of servers and mirrors on multimedia networks and area assignment to base stations in mobile and wireless networks are also obtained. In discrete geometry, generalization of the 2-dimension ham sandwich problem which was an open problem was solved and NP-completeness of stage illumination problem was also clarified. On discrete games and puzzles, NP-hardness of rotation type cell-mazes and PSPACE-completeness of generarized Tsume-Shogi with a given number of moves were proved. Hardware accelerator for subgraph isomorphism problem was developed and static load balancing of parallel PDE solver for distributed computing environment is also investigated. As technologies for supporting users to utilize a large amount of information now available via Internet, etc, some results on automatic text summarization, a retrieval method for relevant documents and knowledge-acquisition from corpus were also obtained.
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