| Project/Area Number |
11680421
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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 |
情報システム学(含情報図書館学)
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| Research Institution | CHIBA INSTITUTE OF TECHNOLOGY |
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Principal Investigator |
MIYAZAKI Nobuyoshi CHIBA INSTITUTE OF TECHNOLOGY, FACULTY OF ENGINEERING, PROFESSOR, 工学部, 教授 (20265466)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,800,000 (Direct Cost: ¥2,800,000)
Fiscal Year 2000: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 1999: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | INCOMPLETE DATABASE / INTEGRATED QUERY PROCESSING / RETRIEVAL / COMPRESSION / TWO STAGE COMPRESSION |
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| Research Abstract |
The aim of the project is to study the foundation and implementation techniques of information integration systems that process various databases scattered over open environment such as the Internet. Each database in an open environment is considered as an incomplete database which stores a part of a virtual database that consists of various databases. It is necessary to develop an efficient method to retrieve data in many sites which store data in various forms including compressed data. Search engines store data in compressed forms, and they use indices in order to efficiently search necessary data. It is important to consider both efficiency of search and compression ratio in these systems.
Integrated query processing is realized based on incomplete database concepts, and it is possible to implement an incomplete database system using an existing database system. The method to construct such a system is investigated by implementing an experimental system. A compression method called the two stage compression method is also proposed and studied in order to reduce storage and to realize efficient search of globally scattered information. This method combines index-based compression and another ordinary compression method, and it is possible to efficiently retrieve data without compromising compression ratio.
The performance of the two stage compression method is studied by implementing and measuring its performance. The performance of the method can be improved by adopting integrated indices instead of individual indices. The method was evaluated using data of newspapers and magazines, and was improved by variable code size. It is also found that the compression ratio of the method greatly varies when ordinary compression algorithm used in it is chaned.
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