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2020 Fiscal Year Research-status Report

Lyndon文字列による簡潔で高速な文字列処理アルゴリズム

Research Project

Project/Area Number 18K18002
Research InstitutionKyushu University

Principal Investigator

中島 祐人  九州大学, システム情報科学研究院, 助教 (80804682)

Project Period (FY) 2018-04-01 – 2022-03-31
Keywords文字列アルゴリズム / 文字列組合せ論 / Lyndon 文字列
Outline of Annual Research Achievements

本研究課題では,簡潔で高速な文字列処理アルゴリズム開発への新たなアプローチとして,Lyndon 文字列や Lyndon 文字列に基づいたデータ構造の未知の性質を明らかにし,それらを用いたアルゴリズム開発を目的としている.この目的達成のために,Lyndon 文字列に関連するトピックを中心に,様々な文字列処理アルゴリズムに関する問題に3年目である令和2年度も,引き続き取り組んだ.その結果を,2020年度中に,6報の論文を査読付き国際会議にて発表,5報の論文を査読付き国際学術雑誌にて公表している.

これらの研究成果は,文字列圧縮手法の開発,圧縮文字列に対するアルゴリズム,索引構造,文字列の特徴(回文や繰り返し構造)抽出アルゴリズム,動的/準動的な文字列処理アルゴリズム,組合せ的性質の解明などのトピックにおける成果であり,文字列情報学分野の多岐にわたる問題を解決しており,いずれも分野の発展に寄与する重要な成果である.本研究課題の核である Lyndon 文字列の数理的性質の解明や,Lyndon 文字列を利用した文字列処理に関してもいくつかの成果を挙げることに成功している.また,一連の研究により得られた知見やアイデアを元にした新たな研究課題も2021年度より開始しており,本研究課題の延長期間と並行して,さらなる研究の進展を期待できる.さらに,すでに成果を得ている一部の成果も存在しており,国際会議,国際学術雑誌等での公表に向けて現在準備中である.

Current Status of Research Progress
Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

研究業績の概要に示したように,本研究課題の核となるLyndon文字列に関する研究成果に加え,文字列処理アルゴリズムに関連する多くの研究成果が得られている.そのため,本研究課題はおおむね順調に進展しているといえる.

Strategy for Future Research Activity

先に示したように,本研究課題はここまで順調に進んでいる.令和2年度は当初計画の最終年度であったが,世界的な感染症拡大の影響を受け,次年度に一部予算を繰越,本研究課題をさらに推し進めていく計画である.

Causes of Carryover

コロナウイルス感染症拡大の影響を受け,学会等が中止になったため,次年度へ繰り越す.主に,学会等での研究成果発表や論文誌への投稿料などに使用する計画である.

  • Research Products

    (17 results)

All 2021 2020

All Journal Article (11 results) (of which Peer Reviewed: 11 results,  Open Access: 1 results) Presentation (6 results) (of which Int'l Joint Research: 6 results)

  • [Journal Article] Computing longest palindromic substring after single-character or block-wise edits2021

    • Author(s)
      Funakoshi Mitsuru, Nakashima Yuto, Inenaga Shunsuke, Bannai Hideo, Takeda Masayuki
    • Journal Title

      Theoretical Computer Science

      Volume: 859 Pages: 116~133

    • DOI

      10.1016/j.tcs.2021.01.014

    • Peer Reviewed
  • [Journal Article] Practical Grammar Compression Based on Maximal Repeats2020

    • Author(s)
      Furuya Isamu, Takagi Takuya, Nakashima Yuto, Inenaga Shunsuke, Bannai Hideo, Kida Takuya
    • Journal Title

      Algorithms

      Volume: 13 Pages: 103~103

    • DOI

      10.3390/a13040103

    • Peer Reviewed / Open Access
  • [Journal Article] Fast Algorithms for the Shortest Unique Palindromic Substring Problem on Run-Length Encoded Strings2020

    • Author(s)
      Watanabe Kiichi, Nakashima Yuto, Inenaga Shunsuke, Bannai Hideo, Takeda Masayuki
    • Journal Title

      Theory of Computing Systems

      Volume: 64 Pages: 1273~1291

    • DOI

      10.1007/s00224-020-09980-x

    • Peer Reviewed
  • [Journal Article] Space-efficient algorithms for computing minimal/shortest unique substrings2020

    • Author(s)
      Mieno Takuya, Koppl Dominik, Nakashima Yuto, Inenaga Shunsuke, Bannai Hideo, Takeda Masayuki
    • Journal Title

      Theoretical Computer Science

      Volume: 845 Pages: 230~242

    • DOI

      10.1016/j.tcs.2020.09.017

    • Peer Reviewed
  • [Journal Article] Grammar-compressed Self-index with Lyndon Words2020

    • Author(s)
      Kazuya Tsuruta, Dominik Koppl, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda
    • Journal Title

      IPSJ Transactions on Mathematical Modeling and Its Applications

      Volume: 13 Pages: 84~92

    • Peer Reviewed
  • [Journal Article] c-Trie++: A Dynamic Trie Tailored for Fast Prefix Searches2020

    • Author(s)
      Tsuruta Kazuya, Koppl Dominik, Kanda Shunsuke, Nakashima Yuto, Inenaga Shunsuke, Bannai Hideo, Takeda Masayuki
    • Journal Title

      Proceedings of Data Compression Conference 2020

      Volume: 1 Pages: 243-252

    • DOI

      10.1109/DCC47342.2020.00032

    • Peer Reviewed
  • [Journal Article] DAWGs for Parameterized Matching: Online Construction and Related Indexing Structures2020

    • Author(s)
      Katsuhito Nakashima, Diptarama Hendrian, Yuto Nakashima, Ryo Yoshinaka, Shunsuke Inenaga, Hideo Bannai, Ayumi Shinohara, Masayuki Takeda
    • Journal Title

      Proceedings of the 31st Annual Symposium on Combinatorial Pattern Matching

      Volume: 161 Pages: 26:1-26:14

    • DOI

      10.4230/LIPIcs.CPM.2020.26

    • Peer Reviewed
  • [Journal Article] Detecting k-(Sub-)Cadences and Equidistant Subsequence Occurrences2020

    • Author(s)
      Mitsuru Funakoshi, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda, Ayumi Shinohara
    • Journal Title

      Proceedings of the 31st Annual Symposium on Combinatorial Pattern Matching

      Volume: 161 Pages: 12:1-12:11

    • DOI

      10.4230/LIPIcs.CPM.2020.12

    • Peer Reviewed
  • [Journal Article] Towards Efficient Interactive Computation of Dynamic Time Warping Distance2020

    • Author(s)
      Akihiro Nishi, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda
    • Journal Title

      Proceedings of 27th International Symposium on String Processing and Information Retrieval

      Volume: 12303 Pages: 27-41

    • DOI

      10.1007/978-3-030-59212-7\_3

    • Peer Reviewed
  • [Journal Article] Lyndon Words, the Three Squares Lemma, and Primitive Squares2020

    • Author(s)
      Hideo Bannai, Takuya Mieno, Yuto Nakashima
    • Journal Title

      Proceedings of 27th International Symposium on String Processing and Information Retrieval

      Volume: 12303 Pages: 265-273

    • DOI

      10.1007/978-3-030-59212-7\_19

    • Peer Reviewed
  • [Journal Article] On repetitiveness measures of Thue-Morse words2020

    • Author(s)
      Kanaru Kutsukake, Takuya Matsumoto, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda
    • Journal Title

      Proceedings of 27th International Symposium on String Processing and Information Retrieval

      Volume: 12303 Pages: 213-220

    • DOI

      10.1007/978-3-030-59212-7\_15

    • Peer Reviewed
  • [Presentation] c-Trie++: A Dynamic Trie Tailored for Fast Prefix Searches2020

    • Author(s)
      Kazuya Tsuruta, Dominik Koppl, Shunsuke Kanda, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda
    • Organizer
      Data Compression Conference 2020
    • Int'l Joint Research
  • [Presentation] DAWGs for Parameterized Matching: Online Construction and Related Indexing Structures2020

    • Author(s)
      Katsuhito Nakashima, Diptarama Hendrian, Yuto Nakashima, Ryo Yoshinaka, Shunsuke Inenaga, Hideo Bannai, Ayumi Shinohara, Masayuki Takeda
    • Organizer
      The 31st Annual Symposium on Combinatorial Pattern Matching
    • Int'l Joint Research
  • [Presentation] Detecting k-(Sub-)Cadences and Equidistant Subsequence Occurrences2020

    • Author(s)
      Mitsuru Funakoshi, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda, Ayumi Shinohara
    • Organizer
      The 31st Annual Symposium on Combinatorial Pattern Matching
    • Int'l Joint Research
  • [Presentation] Towards Efficient Interactive Computation of Dynamic Time Warping Distance2020

    • Author(s)
      Akihiro Nishi, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda
    • Organizer
      The 27th International Symposium on String Processing and Information Retrieval
    • Int'l Joint Research
  • [Presentation] Lyndon Words, the Three Squares Lemma, and Primitive Squares2020

    • Author(s)
      Hideo Bannai, Takuya Mieno, Yuto Nakashima
    • Organizer
      The 27th International Symposium on String Processing and Information Retrieval
    • Int'l Joint Research
  • [Presentation] On repetitiveness measures of Thue-Morse words2020

    • Author(s)
      Kanaru Kutsukake, Takuya Matsumoto, Yuto Nakashima, Shunsuke Inenaga, Hideo Bannai, Masayuki Takeda
    • Organizer
      The 27th International Symposium on String Processing and Information Retrieval
    • Int'l Joint Research

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Published: 2021-12-27  

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