| Project/Area Number |
13680426
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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 | Soka University |
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Principal Investigator |
KOBAYASHI Kojiro Soka University, Dept. of Eng., Prof., 工学部, 教授 (00016148)
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| Project Period (FY) |
2001 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2001: ¥500,000 (Direct Cost: ¥500,000)
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| Keywords | worst input / worst computation time / heapsort / Burrows-Wheeler transform / block sorting / アルゴリズムの効率 / ソーティング / 事前整列性測度 / ブロックソーティング / 逆転 / 情報圧縮 / 整列性測度 / 連 |
|---|
| Research Abstract |
1. Explicit construction of worst inputs for Heapsort
We explicitly constructed a class of worst inputs for Heapsort by the following steps : (1)the explicit construction of some of the worst inputs for phase 2, (2)the analysis of the transformation realized by phase 1, (3)the explicit construction of some of the worst inputs for phase 1, (4)the proof that there exist worst inputs for phase 1 constructed in (3)that are transformed into worst inputs for phase 2 constructed in (1)by the transforamtion of phase 1.
2. Analysis of the structures in the inputs to block sorting
Block sorting is a part of the Burrows-Wheeler transformation that is used in several recent data compression algorithms. An input to block sorting is the sequence of sequences that are circular shifts of the sequence to be compressed. Such sequences have some structures in themselves and it is possible to design a fast sorting algorithm that utilized these structures. We analyzed the numbers of inversions and the runs in the inputs to block sorting for compressing randomly generated sequences.
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