文字列情報処理の新展開－文字列組み合わせ論と高度データ構造技術の融合－

2014 Fiscal Year Annual Research Report

• Project/Area Number: 26280003
• Research Institution: Kyushu University
• Principal Investigator: 稲永 俊介 九州大学, システム情報科学研究科(研究院, 准教授 (60448404)
• Co-Investigator(Kenkyū-buntansha): 坂内 英夫 九州大学, システム情報科学研究科(研究院, 准教授 (20323644) ; 田部井 靖生 東京工業大学, 情報理工学(系)研究科, 研究員 (20589824)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: アルゴリズム理論 / データ構造 / 文字列情報処理

Outline of Annual Research Achievements

文字列とは，記号の連鎖のことである．コンピュータ上で取り扱うデータの多くは，文字列とみなすことができる．そのため，文字列データを高速かつ省領域で処理する基盤技術の開発は，情報爆発時代における喫緊の課題となっている．

本研究では，文字列の組み合わせ的性質と，高度データ構造技術を融合させることにより，当該分野における諸重要問題を高速かつ省領域に解くアルゴリズムとデータ構造の開発を行っている．本年度の主な研究成果は以下の通りである．

(1) 最小回文分解・最小回文被覆のオンライン計算アルゴリズム，(2) 閉文字列分解のオンライン計算アルゴリズム，(3) リンドン分解の逆問題・列挙アルゴリズム，(4) 整数アルファベット上の文字列に対するLZ78分解アルゴリズム，(5)アーベル連・アーベル被覆の計算アルゴリズム

Current Status of Research Progress

1: Research has progressed more than it was originally planned.

Reason

研究実績概要に述べたとおり，研究初年度ながらすでに多くの研究成果を達成するに至っている．これらの他にも，様々な研究成果が実を結びつつあり，当初の計画を上回るものとなっている．

Strategy for Future Research Activity

提案手法のさらなる高速化・省領域化の実現ために，当該分野の第一線で活躍する研究者が集う会議に積極的に参加し，最新の研究成果を網羅するとともに，新技術開発のためのディスカッションを行う．また，国内の研究集会にも積極的に参加し，国内の研究者との連携・協力も図る．必要に応じて，計算機や周辺機器の購入も適宜行う．

Causes of Carryover

実績報告書に述べたとおり，当初の予想を上回るペースで新たな研究成果が得られている．このため，平成27年度においては，研究成果発表のための出張費・会議登録料，および論文誌掲載費等の支出が多くなると予想される．そこで，H26年度の支出を抑え，H27年度に使用することとした．

Expenditure Plan for Carryover Budget

上述の通り，研究成果発表のための出張費・会議登録料，および論文誌掲載費等に使用する．

Research Products

• [Journal Article] Constructing LZ78 Tries and Position Heaps in Linear Time for Large Alphabets (2015)
  • Author(s): Yuto Nakashima, Tomohiro I, Shunsuke Inenaga, Hideo Bannai and Masayuki Takeda
  • Journal Title: Information Processing Letters Volume: 115(9) Pages: 655-659
  • DOI: 10.1016/j.ipl.2015.04.002
  • Peer Reviewed
• [Journal Article] Detecting regularities on grammar-compressed strings (2015)
  • Author(s): Tomohiro I, Wataru Matsubara, Kouji Shimohira, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda, Kazuyuki Narisawa, and Ayumi Shinohara
  • Journal Title: Information and Computation Volume: 240 Pages: 74-89
  • DOI: 10.1016/j.ic.2014.09.009
  • Peer Reviewed
• [Journal Article] A new characterization of maximal repetitions by Lyndon trees (2015)
  • Author(s): Hideo Bannai, Tomohiro I, Shunsuke Inenaga, Yuto Nakashima, Masayuki Takeda, and Kazuya Tsuruta
  • Journal Title: Proc. ACM-SIAM Symposium on Discrete Algorithms 2015 (SODA 2015) Pages: 562-571
  • DOI: 10.1137/1.9781611973730.38
  • Peer Reviewed
• [Journal Article] Computing Abelian Covers and Abelian Runs (2014)
  • Author(s): Shohei Matsuda, Shunsuke Inenaga, Hideo Bannai, and Masayuki Takeda
  • Journal Title: Proc. Prague Stringology Conference 2014 (PSC 2014) Pages: 43-51
  • Peer Reviewed
• [Journal Article] Closed Factorization (2014)
  • Author(s): Golnaz Badkobeh, Hideo Bannai, Keisuke Goto, Tomohiro I, Costas S. Iliopoulos, Shunsuke Inenaga, Simon J. Puglisi, and Shiho Sugimoto
  • Journal Title: Proc. Prague Stringology Conference 2014 (PSC 2014) Pages: 162-168
  • Peer Reviewed
• [Journal Article] Inferring strings from Lyndon factorization (2014)
  • Author(s): Yuto Nakashima, Takashi Okabe, Tomohiro I, Shunsuke Inenaga, Hideo Bannai and Masayuki Takeda
  • Journal Title: Proc. the 39th International Symposium on Mathematical Foundations of Computer Science (MFCS 2014) Volume: LNCS 8635 Pages: 565-576
  • DOI: 10.1007/978-3-662-44465-8_48
  • Peer Reviewed
• [Journal Article] Computing Palindromic Factorizations and Palindromic Covers On-line (2014)
  • Author(s): Tomohiro I, Shiho Sugimoto, Shunsuke Inenaga, Hideo Bannai and Masayuki Takeda
  • Journal Title: Proc. the 25th Annual Symposium on Combinatorial Pattern Matching (CPM 2014) Volume: LNCS 8486 Pages: 150-161
  • DOI: 10.1007/978-3-319-07566-2_16
  • Peer Reviewed
• [Journal Article] Online pattern matching for string edit distance with moves (2014)
  • Author(s): Yoshimasa Takabatake, Yasuo Tabei, Hiroshi Sakamoto
  • Journal Title: Proc. the 21st International Symposium on String Processing and Information Retrieval (SPIRE 2014) Volume: LNCS 8799 Pages: 203-214
  • DOI: 10.1007/978-3-319-11918-2_20
  • Peer Reviewed
• [Journal Article] Improved ESP-index: a practical self-index for highly repetitive texts (2014)
  • Author(s): Yoshimasa Takabatake, Yasuo Tabei, Hiroshi Sakamoto
  • Journal Title: Proc. the 13th International Symposium on Experimental Algorithms (SEA 2014) Volume: LNCS 8504 Pages: 338-350
  • DOI: 10.1007/978-3-319-07959-2_29
  • Peer Reviewed
• [Presentation] A new characterization of maximal repetitions by Lyndon trees (2015)
  • Author(s): Hideo Bannai, Tomohiro I, Shunsuke Inenaga, Yuto Nakashima, Masayuki Takeda, and Kazuya Tsuruta
  • Organizer: ACM-SIAM Symposium on Discrete Algorithms 2015 (SODA 2015)
  • Place of Presentation: San Diego, USA
  • Year and Date: 2015-01-04 – 2015-01-06
• [Presentation] Online pattern matching for string edit distance with moves (2014)
  • Author(s): Yoshimasa Takabatake, Yasuo Tabei, Hiroshi Sakamoto
  • Organizer: 21st International Symposium on String Processing and Information Retrieval (SPIRE 2014)
  • Place of Presentation: Ouro Preto, Brazil
  • Year and Date: 2014-10-20 – 2014-10-24
• [Presentation] Computing Abelian Covers and Abelian Runs (2014)
  • Author(s): Shohei Matsuda, Shunsuke Inenaga, Hideo Bannai, and Masayuki Takeda
  • Organizer: Prague Stringology Conference 2014 (PSC 2014)
  • Place of Presentation: Prague, Czech Republic
  • Year and Date: 2014-09-01 – 2014-09-03
• [Presentation] Closed Factorization (2014)
  • Author(s): Golnaz Badkobeh, Hideo Bannai, Keisuke Goto, Tomohiro I, Costas S. Iliopoulos, Shunsuke Inenaga, Simon J. Puglisi, and Shiho Sugimoto
  • Organizer: Prague Stringology Conference 2014 (PSC 2014)
  • Place of Presentation: Prague, Czech Republic
  • Year and Date: 2014-09-01 – 2014-09-03
• [Presentation] Inferring strings from Lyndon factorization (2014)
  • Author(s): Yuto Nakashima, Takashi Okabe, Tomohiro I, Shunsuke Inenaga, Hideo Bannai and Masayuki Takeda
  • Organizer: 39th International Symposium on Mathematical Foundations of Computer Science (MFCS 2014)
  • Place of Presentation: Budapest, Hungary
  • Year and Date: 2014-08-25 – 2014-08-29
• [Presentation] Improved ESP-index: a practical self-index for highly repetitive texts (2014)
  • Author(s): Yoshimasa Takabatake, Yasuo Tabei, Hiroshi Sakamoto
  • Organizer: 13th International Symposium on Experimental Algorithms (SEA 2014)
  • Place of Presentation: Copenhagen, Denmark
  • Year and Date: 2014-06-29 – 2014-07-01
• [Presentation] Computing Palindromic Factorizations and Palindromic Covers On-line (2014)
  • Author(s): Tomohiro I, Shiho Sugimoto, Shunsuke Inenaga, Hideo Bannai and Masayuki Takeda
  • Organizer: 25th Annual Symposium on Combinatorial Pattern Matching (CPM 2014)
  • Place of Presentation: Moscow, Russia
  • Year and Date: 2014-06-16 – 2014-06-16