篠原・吉仲研究室 on

文字列処理

Mon, 01 Jan 0001 00:00:00 +0000

ここで「文字列処理」についての詳しい解説をMarkdown形式で記述します。図表や数式なども自由に入れられます。

String Processing プロジェクト

機械学習の理論と応用

Mon, 01 Jan 0001 00:00:00 +0000

ここで「機械学習」についての詳しい解説をMarkdown形式で記述します。図表や数式なども自由に入れられます。

Machine Learning プロジェクト

ゲーム情報学

Mon, 01 Jan 0001 00:00:00 +0000

ここで「ゲーム情報学」についての詳しい解説をMarkdown形式で記述します。図表や数式なども自由に入れられます。

Game Informatics プロジェクト

花見 2026

Sun, 12 Apr 2026 00:00:00 +0000

2026年4月12日(日)に西公園で花見を行いました。

卒業式

Wed, 25 Mar 2026 00:00:00 +0000

学位論文授与式（通称：卒業式）の後の集合写真．

天気にも恵まれました．

CGP2026-Ishibashi

Sun, 22 Feb 2026 00:00:00 +0000

Nikoli社のペンシルパズルの1種である「カナオレ」について，その計算複雑性を解析した．元のパズルのNP完全性を示すとともに，様々な制限を加えた際の複雑性の変化を観察した．

2026-03-WALCOM

Thu, 01 Jan 2026 00:00:00 +0000

(Induced) Subgraph Isomorphism and Maximum Common (Induced) Subgraph are fundamental problems in graph pattern matching and similarity computation. In graphs derived from time-series data or protein structures, a natural total ordering of vertices often arises from…

SOFSEM2026

Thu, 01 Jan 2026 00:00:00 +0000

Given a set of results from range minimum queries (RMQs), our task is to construct a sequence that is consistent with the results of the queries. We study two types of RMQs: a value-based RMQ returns the minimum value and an index-based RMQ returns the index of the…

CJCDCGGG2025

Sun, 14 Sep 2025 00:00:00 +0000

CIAC2025

Thu, 12 Jun 2025 00:00:00 +0000

The longest common subsequence (LCS) is a fundamental problem in string processing which has numerous algorithmic studies, extensions, and applications. A sequence $$u_1, \ldots , u_f$$…

CPM2025

Sun, 01 Jun 2025 00:00:00 +0000

Run-length straight-line programs (RLSLPs) are a technique for grammar-based compression, allowing any string to be represented with optimal space for $\delta$, the substring complexity of the string. We address the compressed pattern matching problem for RLSLPs: Given a compressed text in RLSLP format and an uncompressed pattern, determine if the pattern appears in the text. This paper proposes an algorithm that solves this problem in linear time with respect to the size of the grammar and the length of the pattern.

卒業式

Tue, 25 Mar 2025 00:00:00 +0000

学位論文授与式（通称：卒業式）の後の集合写真．

天気にも恵まれました．

CGP2025-BusOut

Sat, 08 Mar 2025 00:00:00 +0000

Takehiro Ishibashi, Ryo Yoshinaka, Ayumi Shinohara:BusOut is NP-complete. arXiv:2505.09165

LA2024Winter

Tue, 28 Jan 2025 00:00:00 +0000

冬のLAシンポジウム in 京都 2024

Tue, 28 Jan 2025 00:00:00 +0000

冬のLAシンポジウム2024に参加しました！

SOFSEM2025

Mon, 20 Jan 2025 00:00:00 +0000

This paper is concerned with learning some context-free languages (cfls) over infinite alphabets from membership and equivalence queries. Argyros and D’Antoni (2018) proposed a query learning algorithm for regular languages over infinite alphabets using…

Acta-Informatica-2024

Thu, 01 Aug 2024 00:00:00 +0000

Given a text and a pattern over an alphabet, the classic exact matching problem searches for all occurrences of the pattern in the text. Unlike exact match

2024-01-ICALP

Mon, 01 Jul 2024 00:00:00 +0000

A parameterized string (p-string) is a string over an alphabet (Σ_s ∪ Σ_p), where Σ_s and Σ_p are disjoint alphabets for static symbols (s-symbols) and for parameter symbols (p-symbols), respectively. Two p-strings x and y are said to parameterized match (p-match) if and only if x can be transformed into y by applying a bijection on Σ_p to every occurrence of p-symbols in x. The indexing problem for p-matching is to preprocess a p-string T of length n so that we can efficiently find the occurrences of substrings of T that p-match with a given pattern. Let σ_s and respectively σ_p be the numbers of distinct s-symbols and p-symbols that appear in T and σ = σ_s + σ_p. Extending the Burrows-Wheeler Transform (BWT) based index for exact string pattern matching, Ganguly et al. [SODA 2017] proposed parameterized BWTs (pBWTs) to design the first compact index for p-matching, and posed an open problem on how to construct the pBWT-based index in compact space, i.e., in O(n lg |Σ_s ∪ Σ_p|) bits of space. Hashimoto et al. [SPIRE 2022] showed how to construct the pBWT for T, under the assumption that Σ_s ∪ Σ_p = [0..O(σ)], in O(n lg σ) bits of space and O(n (σ_p lg n)/(lg lg n)) time in an online manner while reading the symbols of T from right to left. In this paper, we refine Hashimoto et al.’s algorithm to work in O(n lg σ) bits of space and O(n (lg σ_p lg n)/(lg lg n)) time in a more general assumption that Σ_s ∪ Σ_p = [0..n^{O(1)}]. Our result has an immediate application to constructing parameterized suffix arrays in O(n (lg σ_p lg n)/(lg lg n)) time and O(n lg σ) bits of working space. We also show that our data structure can support backward search, a core procedure of BWT-based indexes, at any stage of the online construction, making it the first compact index for p-matching that can be constructed in compact space and even in an online manner.

TCS2024-Diptarama

Mon, 01 Jul 2024 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

TCS2024-Kawahara

Mon, 01 Jul 2024 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

CPM2024

Mon, 24 Jun 2024 00:00:00 +0000

SOFSEM2024

Fri, 23 Feb 2024 00:00:00 +0000

2024-08-SEAA

Mon, 01 Jan 2024 00:00:00 +0000

STRセミナー2024 in札幌

Mon, 01 Jan 2024 00:00:00 +0000

STRセミナー2024札幌に参加しました！

オープンキャンパス 2024

Mon, 01 Jan 2024 00:00:00 +0000

2024年オープンキャンパスが開催されました。

ソフトボール大会決勝 2024

Mon, 01 Jan 2024 00:00:00 +0000

ソフトボール大会の決勝戦がありました！

芋煮2024

Mon, 01 Jan 2024 00:00:00 +0000

広瀬川沿いで芋煮会を行いました!!

花見 2024

Mon, 01 Jan 2024 00:00:00 +0000

2024年4月13日(土)に西公園で花見を行いました。

電気・情報系・通研駅伝大会 2024

Mon, 01 Jan 2024 00:00:00 +0000

駅伝大会がありました！

Theoretical Computer Science 2023

Thu, 02 Nov 2023 00:00:00 +0000

Various forms of sorting problems have been studied over the years. Recently, two kinds of sorting puzzle apps are popularized. In these puzzles, we are given a set of bins filled with colored units, balls or water, and some empty bins. These puzzles allow us to move colored units from a bin to another when the colors involved match in some way or the target bin is empty. The goal of these puzzles is to sort all the color units in order. We investigate computational complexities of these puzzles. We first show that these two puzzles are essentially the same from the viewpoint of solvability. That is, an instance is sortable by ball-moves if and only if it is sortable by water-moves. We also show that every yes-instance has a solution of polynomial length, which implies that these puzzles belong to in NP. We then show that these puzzles are NP-complete. For some special cases, we give polynomial-time algorithms. We finally consider the number of empty bins sufficient for making all instances solvable and give non-trivial upper and lower bounds in terms of the number of filled bins and the capacity of bins.

電気・情報系・通研駅伝大会 2023

Wed, 01 Nov 2023 00:00:00 +0000

電気・情報系・通研駅伝大会に参加しました．24チーム中7位で，惜しくも入賞は逃しましたが，研究室の団結が一段と強まりました．（11月25日）

芋煮 2023

Sun, 01 Oct 2023 00:00:00 +0000

芋煮会を行いました．（10月16日）

SPIRE2023

Fri, 01 Sep 2023 00:00:00 +0000

The parameterized matching problem is a variant of string matching, which is to search for all parameterized occurrences of a pattern P in a text T. In considering matching algorithms, the combinatorial natures of strings, especially periodicity, play an important…

STRセミナー 2023

Fri, 01 Sep 2023 00:00:00 +0000

STRセミナー2023において研究発表を行いました．（埼玉・川越，9月21日～22日）

ICGI2023

Wed, 12 Jul 2023 00:00:00 +0000

This paper is concerned with the identification in the limit from positive data of substitutable context-free languages CFLs over infinite alphabets. [ClarkE07] showed that substitutable CFLs over finite alphabets are learnable in this learning paradigm. We show that substitutable CFLs generated by grammars whose production rules may have predicates that represent sets of potentially infinitely many terminal symbols in a compact manner are learnable if the terminal symbol sets represented by those predicates are learnable, under a certain condition. This can be seen as a result parallel to [ArgyrosDA2018]’s work (2018) that amplifies the query learnability of predicate classes to that of symbolic automata classes. Our result is the first that shows such amplification is possible for identifying some CFLs in the limit from positive data.

ICGI2023-Kanazawa

Wed, 12 Jul 2023 00:00:00 +0000

We consider an extension of distributional learning of context-free languages (from positive data and membership queries), where nonterminals are represented by extended regular expressions (allowi…

ICGI 2023

Sat, 01 Jul 2023 00:00:00 +0000

国際会議ICGI2023において研究発表を行いました．（モロッコ・ラバト，7月10日～13日）

2022年度電気関係学会東北支部連合大会情報処理学会東北支部奨励賞受賞

Fri, 14 Apr 2023 00:00:00 +0000

2022年8月23～24日に開催された電気関係学会東北支部連合大会にて、当研究室の松野直也が「動画内のオブジェクトの動く方向に柔軟に適応したリボンの作成手法」という題目で発表を行い、情報処理学会東北支部奨励賞を受賞しました。

2023-01-WALCOM-2

Wed, 01 Mar 2023 00:00:00 +0000

Intersection graphs are well-studied in the area of graph algorithms. Some intersection graph classes are known to have algorithms enumerating all unlabeled graphs by reverse search. Since these algorithms output graphs one by one and the numbers of graphs in these…

WALCOM2023-Kumagai

Wed, 01 Mar 2023 00:00:00 +0000

Position heaps are index structures of text strings used for the string matching problem. They are rooted trees whose edges and nodes are labeled and numbered, respectively. This paper is concerned with variants of the inverse problem of position heap construction…

JPHACKS 2022 Award Day にてJPHACKS Innovator認定と合同会社MIRAISE賞を受賞

Wed, 08 Feb 2023 00:00:00 +0000

2022年11月13日に行われたJPHACKS 2022 Award Dayにて、当研究室の水野祥太が所属するチーム「くまさん」が開発したアプリ「VRooM」が、JPHACKS Innovator認定と合同会社MIRAISE賞（企業賞）を受賞しました。

2023-02-la-sympo-winter

Wed, 01 Feb 2023 00:00:00 +0000

LA sympo in Winter

Mon, 30 Jan 2023 00:00:00 +0000

2022-11-game-prog

Sun, 13 Nov 2022 00:00:00 +0000

SPIRE2022

Wed, 09 Nov 2022 00:00:00 +0000

電気・情報系・通研駅伝大会 2022

Tue, 01 Nov 2022 00:00:00 +0000

電気・情報系・通研駅伝大会に参加しました．20チーム中3位でした！さらに田中聡（修士2年）が第1区の区間賞を受賞しました．また弊研究室は，大会運営も務め，3年ぶりの大会を成功に導きました．（11月26日）

技育展2022 インフラ/セキュリティ部門最優秀賞受賞

Fri, 21 Oct 2022 00:00:00 +0000

2022年8月から9月にかけて開催された「技育展2022」「インフラ/セキュリティ」部門で、博士前期課程2年の浦田智稀君と江上尚志君のチームが開発した「AI撲滅AI」が、最優秀賞を受賞しました。

Theoretical Computer Science 2022

Fri, 14 Oct 2022 00:00:00 +0000

Two strings $x$ and $y$ over $\Sigma \cup \Pi$ of equal length are said to parameterized match (p-match) if there is a renaming bijection $f:\Sigma \cup \Pi \rightarrow \Sigma \cup \Pi$ that is identity on $\Sigma$ and transforms $x$ to $y$ (or vice versa). The p-matching problem is to look for substrings in a text that p-match a given pattern. In this paper, we propose parameterized suffix automata (p-suffix automata) and parameterized directed acyclic word graphs (PDAWGs) which are the p-matching versions of suffix automata and DAWGs. While suffix automata and DAWGs are equivalent for standard strings, we show that p-suffix automata can have $\Theta(n^2)$ nodes and edges but PDAWGs have only $O(n)$ nodes and edges, where $n$ is the length of an input string. We also give an $O(n |\Pi| \log (|\Pi| + |\Sigma|))$-time $O(n)$-space algorithm that builds the PDAWG in a left-to-right online manner. As a byproduct, it is shown that the \emph{parameterized suffix tree} for the reversed string can also be built in the same time and space, in a right-to-left online manner. This duality also leads us to two further efficient algorithms for p-matching: Given the parameterized suffix tree for the reversal of the input string $T$, one can build the PDAWG of $T$ in $O(n)$ time in an offline manner; One can perform \emph{bidirectional} p-matching in $O(m \log (|\Pi|+|\Sigma|) + occ)$ time using $O(n)$ space, where $m$ denotes the pattern length and $\mathit{occ}$ is the number of pattern occurrences in the text $T$.

STRセミナー2022 熊谷滉士郎若手奨励賞受賞

Mon, 12 Sep 2022 00:00:00 +0000

2022年9月2日〜4日，神戸国際会議場で開催されたSTRセミナーで，当研究室の熊谷滉士郎君が「ポジションヒープ構築の逆問題」と題して発表を行い，若手奨励賞を受賞しました．

STRセミナー2022

Thu, 01 Sep 2022 00:00:00 +0000

2022年9月2〜4日，神戸国際会議場で開催されたSTRセミナーで，修士二年の浦田智稀，江上尚志，熊谷滉士郎が研究発表を行いました．

CPM2022

Sun, 26 Jun 2022 00:00:00 +0000

2022-02-la-sympo-winter-dava

Wed, 02 Feb 2022 00:00:00 +0000

2022-02-la-sympo-winter-ichikawa

Wed, 02 Feb 2022 00:00:00 +0000

2022-02-la-sympo-winter-ishizuka

Wed, 02 Feb 2022 00:00:00 +0000

ICGI2021-Kambe

Mon, 23 Aug 2021 00:00:00 +0000

We propose an inside-outside algorithm for stochastic macro grammars. Our approach is based on types, which has been inspired by type-based approaches to reasoning about functional programs and higher-order grammars. By considering type derivations instead of ordinary word derivation sequences, we can naturally extend the standard inside-outside algorithm for stochastic context-free grammars to obtain the algorithm for stochastic macro grammars. We have implemented the algorithm and confirmed its effectiveness through an application to the learning of macro grammars.

ICGI2023-Kaito

Mon, 23 Aug 2021 00:00:00 +0000

We propose a query learning algorithm for an extension of weighted finite automata (WFAs), named symbolic weighted finite automata (SWFAs), which can handle strings over infinite alphabets more efficiently. Based on the idea of symbolic finite automata, SWFAs generalize WFAs by allowing transitions to be functions from a possibly infinite alphabet to weights. Our algorithm can learn SWFAs if functions in transitions are also learnable by queries. We also investigate minimization and equivalence checking for SWFAs.

ICGI2023-kanazawa

Mon, 23 Aug 2021 00:00:00 +0000

We consider a generalization of the “dual” approach to distributional learning of context-free grammars, where each nonterminal $A$ is associated with a string set $X_A$ characterized by a finite set $C$ of contexts. Rather than letting $X_A$ be the set of all strings accepted by all contexts in $C$ as in previous works, we allow more flexible uses of the contexts in $C$, using some of them positively (contexts that accept the strings in $X_A$) and others negatively (contexts that do not accept any strings in $X_A$). The resulting more general algorithm works in essentially the same way as before, but on a larger class of context-free languages.

工学部長賞受賞

Thu, 25 Mar 2021 00:00:00 +0000

2021年3月25日に当研究室の浦田智稀君（学部４年）が東北大学工学部長賞を受賞しました。

2021-01-WALCOM

Mon, 01 Mar 2021 00:00:00 +0000

For a graph class $\mathcal {C}$ , the $\mathcal {C}$…

2020-12-comp

Fri, 04 Dec 2020 00:00:00 +0000

SPIRE2020

Tue, 13 Oct 2020 00:00:00 +0000

Covers are a kind of quasiperiodicity in strings. A string $C$ is a cover of another string $T$ if any position of $T$ is inside some occurrence of $C$ in $T$. The shortest and longest cover arrays of $T$ have the lengths of the shortest and longest covers of each prefix of $T$, respectively. The literature has proposed linear-time algorithms computing longest and shortest cover arrays taking border arrays as input. An equivalence relation $\approx$ over strings is called a substring consistent equivalence relation (SCER) iff $X \approx Y$ implies (1) $|X|=|Y|$ and (2) $X[i:j] \approx Y[i:j]$ for all $1 \leq i \leq j \leq |X|$. In this paper, we generalize the notion of covers for SCERs and prove that existing algorithms to compute the shortest cover array and the longest cover array of a string T under the identity relation will work for any SCERs taking the accordingly generalized border arrays.

2020-01-ETFA

Tue, 01 Sep 2020 00:00:00 +0000

篠原教授が東北大学総長教育賞を受賞

Wed, 01 Jul 2020 00:00:00 +0000

2020年7月1日　当研究室の篠原歩教授が令和元年度東北大学総長教育賞を受賞しました。

詳細はこちら

CPM2020-Funakoshi

Wed, 17 Jun 2020 00:00:00 +0000

The equidistant subsequence pattern matching problem is considered. Given a pattern string $P$ and a text string $T$, we say that $P$ is an equidistant subsequence of $T$ if $P$ is a subsequence of the text such that consecutive symbols of $P$ in the occurrence are equally spaced. We can consider the problem of equidistant subsequences as generalizations of (sub-)cadences. We give bit-parallel algorithms that yield $o(n^2)$ time algorithms for finding $k$-(sub-)cadences and equidistant subsequences. Furthermore, $O(n \log^2{n})$ and $O(n \log{n})$ time algorithms, respectively for equidistant and Abelian equidistant matching for the case $|P| = 3$, are shown. The algorithms make use of a technique that was recently introduced which can efficiently compute convolutions with linear constraints.

CPM2020-Köppl

Wed, 17 Jun 2020 00:00:00 +0000

One of the most well-known variants of the Burrows-Wheeler transform (BWT) [Burrows and Wheeler, 1994] is the bijective BWT (BBWT) [Gil and Scott, arXiv 2012], which applies the extended BWT (EBWT) [Mantaci et al., TCS 2007] to the multiset of Lyndon factors of a given text. Since the EBWT is invertible, the BBWT is a bijective transform in the sense that the inverse image of the EBWT restores this multiset of Lyndon factors such that the original text can be obtained by sorting these factors in non-increasing order. In this paper, we present algorithms constructing or inverting the BBWT in-place using quadratic time. We also present conversions from the BBWT to the BWT, or vice versa, either (a) in-place using quadratic time, or (b) in the run-length compressed setting using $O(n \lg{r} / \lg{\lg{r}})$ time with $O(r \lg{n})$ bits of words, where r is the sum of character runs in the BWT and the BBWT.

CPM2020-Nakashima

Wed, 17 Jun 2020 00:00:00 +0000

Two strings $x$ and $y$ over $\Sigma \cup \Pi$ of equal length are said to parameterized match (p-match) if there is a renaming bijection $f:\Sigma \cup \Pi \to \Sigma \cup \Pi$ that is identity on $\Sigma$ and transforms $x$ to $y$ (or vice versa). The p-matching problem is to look for substrings in a text that p-match a given pattern. In this paper, we propose parameterized suffix automata (p-suffix automata) and parameterized directed acyclic word graphs (PDAWGs) which are the p-matching versions of suffix automata and DAWGs. While suffix automata and DAWGs are equivalent for standard strings, we show that p-suffix automata can have $\Theta(n^2)$ nodes and edges but PDAWGs have only $O(n)$ nodes and edges, where $n$ is the length of an input string. We also give $O(n |\Pi| \log{(|\Pi| + |\Sigma|)})$-time $O(n)$-space algorithm that builds the PDAWG in a left-to-right online manner. As a byproduct, it is shown that the parameterized suffix tree for the reversed string can also be built in the same time and space, in a right-to-left online manner.

SEA2020

Tue, 16 Jun 2020 00:00:00 +0000

Given a text $T$ of length $n$ and a pattern $P$ of length $m$, the string matching problem is a task to find all occurrences of $P$ in $T$. In this study, we propose an algorithm that solves this problem in $O((n + m)q)$ time considering the distance between two adjacent occurrences of the same $q$-gram contained in $P$. We also propose a theoretical improvement of it which runs in $O(n + m)$ time, though it is not necessarily faster in practice. We compare the execution times of our and existing algorithms on various kinds of real and artificial datasets such as an English text, a genome sequence and a Fibonacci string. The experimental results show that our algorithm is as fast as the state-of-the-art algorithms in many cases, particularly when a pattern frequently appears in a text.

情報処理学会東北支部学生奨励賞受賞

Mon, 01 Jun 2020 00:00:00 +0000

当研究室の石塚将太君（修士１年）が、情報処理学会東北支部学生奨励賞を受賞しました。

TCS2020-Narisada-gap

Mon, 06 Apr 2020 00:00:00 +0000

In this paper, we introduce new types of approximate palindromes called single-arm-gapped palindromes (shortly SAGPs). A SAGP contains a gap in either its left or right arm, which is in the form of either $wgucu^Rw^R$ or $wucu^Rgw^R$, where $w$ and $u$ are non-empty strings, $w^R$ and $u^R$ are respectively the reversed strings of $w$ and $u$, $g$ is a string called a gap, and $c$ is either a single character or the empty string. Here we call $wu$ and $u^Rw^R$ the arm of the SAGP, and $|uv|$ the length of the arm. We classify SAGPs into two groups: those which have $ucu^R$ as a maximal palindrome (type-1), and the others (type-2). We propose several algorithms to compute type-1 SAGPs with longest arms occurring in a given string, based on suffix arrays. Then, we propose a linear-time algorithm to compute all type-1 SAGPs with longest arms, based on suffix trees. Also, we show how to compute type-2 SAGPs with longest arms in linear time. We also perform some preliminary experiments to show practical performances of the proposed methods.

TCS2020-Narisada-walk

Mon, 06 Apr 2020 00:00:00 +0000

Abstract We consider the problem of inferring an edge-labeled graph from the sequence of edge labels seen in a walk on that graph. It has been known that this problem is solvable in $O( n \log{n})$ time when the targets are path or cycle graphs. This paper presents an online algorithm for the problem of this restricted case that runs in $O ( n )$ time, based on Manacher’s algorithm for computing all the maximal palindromes in a string.

LAシンポジウム冬 2019

Wed, 01 Apr 2020 00:00:00 +0000

京都大学で行われた冬のLAシンポジウムにてD1のJargalsaikhan Davaajavさん, M2の中島克仁君, M1の菊池なつみさんが研究発表を行いました。（2月5日～7日）

DCC2020

Wed, 25 Mar 2020 00:00:00 +0000

We propose a new approach for universal lossless text compression, based on grammar compression. In the literature, a target string $T$ has been compressed as a context-free grammar $G$ in Chomsky normal form satisfying $L(G) = T$. Such a grammar is often called a straight-line program (SLP). In this paper, we consider a probabilistic grammar $G$ that generates $T$, but not necessarily as a unique element of $L(G)$. In order to recover the original text $T$ unambiguously, we keep both the grammar G and the derivation tree of $T$ from the start symbol in $G$, in compressed form. We show some simple evidence that our proposal is indeed more efficient than SLPs for certain texts, both from theoretical and practical points of view.

総長賞受賞

Wed, 25 Mar 2020 00:00:00 +0000

2020年3月25日に行われた当学の学位記授与式において、当研究室の鈴木海渡君（学部４年）が総長賞を受賞しました。

2020-02-la-winter-dava

Fri, 07 Feb 2020 00:00:00 +0000

2020-02-la-winter-nakashima

Fri, 07 Feb 2020 00:00:00 +0000

2020-02-la-winter-natsumi

Fri, 07 Feb 2020 00:00:00 +0000

SOFSEM 2020

Sat, 01 Feb 2020 00:00:00 +0000

キプロスのリマソルで行われた国際学会SOFSEM2020において研究発表を行いました (1月20日～1月24日)

SOFSEM2020

Wed, 22 Jan 2020 00:00:00 +0000

Given a text and a pattern over an alphabet, the classic exact matching problem searches for all occurrences of pattern P in text T. Unlike the exact matching problem, order-preserving pattern matching considers the relative order of elements, rather than their exact values. In this paper, we propose the first parallel algorithm for the OPPM problem. Our algorithm is based on the “duel-and-sweep” algorithm. For a pattern of length $m$ and a text of length $n$, our algorithm runs in $O(\log^3{m})$ time and $O(n \log^3{m})$ work on the Priority CRCW PRAM.

篠原教授が東北大学全学教育貢献賞を受賞

Tue, 07 Jan 2020 00:00:00 +0000

2020年1月7日に当研究室の篠原歩教授が令和元年度東北大学全学教育貢献賞（1月7日）を受賞しました。

詳細はこちら

2020-01-Algorithmica

Wed, 01 Jan 2020 00:00:00 +0000

We consider the construction of the suffix tree and the directed acyclic word graph (DAWG) indexing data structures for a collection $$\mathcal {T}$$ of te

2020-01-SOFSEM-Doctoral-Student-Research-Forum

Wed, 01 Jan 2020 00:00:00 +0000

2020-01-SOFSEM-Doctoral-Student-Research-Forum-2

Wed, 01 Jan 2020 00:00:00 +0000

2019-12-comp

Fri, 13 Dec 2019 00:00:00 +0000

JPHACKS2019 Hack Day仙台大会 Best Hack Day Award 受賞

Fri, 08 Nov 2019 00:00:00 +0000

2019年10月26日,27日に東北大学で行われたJPHACKS2019 Hack Day仙台大会において，

当研究室の渡部航也，對馬裕樹，石塚将太，田村裕太(学部２年)の計４人のチーム「(ぽん)^2ぺいん」で開発した作品「Music @」がBest Hack Day Awardを獲得しました．

石田實記念財団研究奨励賞を受賞

Fri, 08 Nov 2019 00:00:00 +0000

2019年11月8日　当研究室の吉仲亮准教授が石田實記念財団より研究奨励賞を受賞しました。

PSC 2019

Tue, 01 Oct 2019 00:00:00 +0000

国際学会PSCにおいて研究発表を行ってきました (8月26日～8月28日，チェコ)

2019-09-fit

Thu, 05 Sep 2019 00:00:00 +0000

2019-01-SSRR

Sun, 01 Sep 2019 00:00:00 +0000

2019-08-tsjc

Thu, 22 Aug 2019 00:00:00 +0000

2019-01-PSC

Thu, 01 Aug 2019 00:00:00 +0000

2019-01-SEA

Sat, 01 Jun 2019 00:00:00 +0000

This paper considers enumeration of specific subgraphs of a given graph by using a data structure called a zero-suppressed binary decision diagram (ZDD). A ZDD can represent the set of solutions quite compactly. Recent studies have demonstrated that a technique…

2019-05-comp

Fri, 10 May 2019 00:00:00 +0000

花見 2019

Wed, 01 May 2019 00:00:00 +0000

西公園で花見をしました（4月13日）

工学部長賞受賞

Tue, 26 Mar 2019 00:00:00 +0000

2019年3月26日　当研究室の星川研太郎君（学部４年）が東北大学工学部長賞を受賞しました。

2019-01-Algorithms

Tue, 01 Jan 2019 00:00:00 +0000

A multi-track string is a tuple of strings of the same length. Given the pattern and text of two multi-track strings, the permuted pattern matching problem is to find the occurrence positions of all permutations of the pattern in the text. In this paper, we propose several algorithms for permuted pattern matching. Our first algorithm, which is based on the Knuth–Morris–Pratt (KMP) algorithm, has a fast theoretical computing time with O ( m k ) as the preprocessing time and O ( n k log σ ) as the matching time, where n, m, k, σ , and occ denote the length of the text, the length of the pattern, the number of strings in the multi-track, the alphabet size, and the number of occurrences of the pattern, respectively. We then improve the KMP-based algorithm by using an automaton, which has a better experimental running time. The next proposed algorithms are based on the Boyer–Moore algorithm and the Horspool algorithm that try to perform pattern matching. These algorithms are the fastest experimental algorithms. Furthermore, we propose an extension of the AC-automaton algorithm that can solve dictionary matching on multi-tracks, which is a task to find multiple multi-track patterns in a multi-track text. Finally, we propose filtering algorithms that can perform permuted pattern matching quickly in practice.

2019-01-GandALF

Tue, 01 Jan 2019 00:00:00 +0000

We propose a query learning algorithm for residual symbolic finite automata (RSFAs). Symbolic finite automata (SFAs) are finite automata whose transitions are labeled by predicates over a Boolean algebra, in which a big collection of characters leading the same transition may be represented by a single predicate. Residual finite automata (RFAs) are a special type of non-deterministic finite automata which can be exponentially smaller than the minimum deterministic finite automata and have a favorable property for learning algorithms. RSFAs have both properties of SFAs and RFAs and can have more succinct representation of transitions and fewer states than RFAs and deterministic SFAs accepting the same language. The implementation of our algorithm efficiently learns RSFAs over a huge alphabet and outperforms an existing learning algorithm for deterministic SFAs. The result also shows that the benefit of non-determinism in efficiency is even larger in learning SFAs than non-symbolic automata.

2019-01-J-Comput-Syst-Sci

Tue, 01 Jan 2019 00:00:00 +0000

Abstract Approaches based on the idea generically called distributional learning have been making great success in the algorithmic learning of several rich subclasses of context-free languages and their extensions. Those language classes are defined by properties concerning string-context relation. In this paper, we present a distributional learning algorithm for conjunctive grammars with the k -finite context property ( k - fcp ) for each natural number k . We also compare our result with the closely related work by Clark et al. (JMLR 2010) [5] on learning some context-free grammars using contextual binary feature grammars ( cbfg s). We prove that the context-free grammars targeted by their algorithm have the k - fcp . Moreover, we show that every exact cbfg has the k - fcp , too, while not all of them are learnable by their algorithm. Clark et al. conjectured a learning algorithm for exact cbfg s should exist. This paper answers their conjecture in a positive way.

2019-01-J-Graph-Algorithms-Appl

Tue, 01 Jan 2019 00:00:00 +0000

The problems of Permutation Routing via Matching and Token Swapping are reconfiguration problems on graphs. This paper is concerned with the complexity of those problems and a colored variant. For a given graph where each vertex has a unique token on it, those problems require to find a shortest way to modify a token placement into another by swapping tokens on adjacent vertices. While all pairs of tokens on a matching can be exchanged at once in Permutation Routing via Matching, Token Swapping allows only one pair of tokens can be swapped. In the colored version, vertices and tokens are colored and the goal is to relocate tokens so that each vertex has a token of the same color. We investigate the time complexity of several restricted cases of those problems and show when those problems become tractable and remain intractable.

2019-01-Theor-Comput-Sci

Tue, 01 Jan 2019 00:00:00 +0000

Abstract The dictionary matching is a task to find all occurrences of pattern strings in a set D (called a dictionary) on a text string T. The Aho–Corasick-automaton (AC-automaton) which is built on D is a fundamental data structure which enables us to solve the dictionary matching problem in O ( d log ⁡ σ ) preprocessing time and O ( n log ⁡ σ + occ ) matching time, where d is the total length of the patterns in the dictionary D, n is the length of the text, σ is the alphabet size, and occ is the total number of occurrences of all the patterns in the text. The dynamic dictionary matching is a variant where patterns may dynamically be inserted into and deleted from the dictionary D. This problem is called semi-dynamic dictionary matching if only insertions are allowed. In this paper, we propose two efficient algorithms that can solve both problems with some modifications. For a pattern of length m, our first algorithm supports insertions in O ( m log ⁡ σ + log ⁡ d / log ⁡ log ⁡ d ) time and pattern matching in O ( n log ⁡ σ + occ ) for the semi-dynamic setting. This algorithm also supports both insertions and deletions in O ( σ m + log ⁡ d / log ⁡ log ⁡ d ) time and pattern matching in O ( n ( log ⁡ d / log ⁡ log ⁡ d + log ⁡ σ ) + occ ( log ⁡ d / log ⁡ log ⁡ d ) ) time for the dynamic dictionary matching problem by some modifications. This algorithm is based on the directed acyclic word graph (DAWG) of Blumer et al. (JACM 1987). Our second algorithm, which is based on the AC-automaton, supports insertions in O ( m log ⁡ σ + u f + u o ) time for the semi-dynamic setting and supports both insertions and deletions in O ( σ m + u f + u o ) time for the dynamic setting, where u f and u o respectively denote the numbers of states in which the failure function and the output function need to be updated. This algorithm performs pattern matching in O ( n log ⁡ σ + occ ) time for both settings. Our algorithm achieves optimal update time for AC-automaton based methods over constant-size alphabets, since any algorithm which explicitly maintains the AC-automaton requires Ω ( m + u f + u o ) update time.

SPIRE2018

Thu, 11 Oct 2018 00:00:00 +0000

We consider the problem of inferring an edge-labeled graph from the sequence of edge labels seen in a walk of that graph. It has been known that this problem is solvable in $O(n\log n)$ time when the targets are path or cycle graphs. This paper presents an online algorithm for the problem of this restricted case that runs in $O(n)$ time, based on Manacher’s algorithm for computing all the maximal palindromes in a string.

2018-01-CIAA

Wed, 01 Aug 2018 00:00:00 +0000

A cryptarithm is a mathematical puzzle where given an arithmetic equation written with letters rather than numerals, a player must discover an assignment of numerals on letters that makes the equation hold true. In this paper, we propose a method to construct a DFA…

情報処理学会東北支部第13回野口研究奨励賞を受賞

Wed, 27 Jun 2018 00:00:00 +0000

2018年6月20日、当研究室のDiptarama Hendrian 助教が情報処理学会東北支部の「第13回野口研究奨励賞」を受賞しました。

この賞は，情報処理分野に関するより一層の研究開発を奨励することを趣旨として優秀な学術論文を出版した東北支部会員の若手研究者に対し授与されるものです．

工学部長賞受賞

Mon, 26 Mar 2018 00:00:00 +0000

2018年3月26日　当研究室の小林賢君（学部４年）が工学部長賞を受賞しました。

2018-01-SOFSEM

Thu, 01 Feb 2018 00:00:00 +0000

Given a text and a pattern over two types of symbols called constants and variables, the parameterized pattern matching problem is to find all occurrences of substrings of the text that the pattern matches by substituting a variable in the text for each variable in…

2018-01-SOFSEM-2

Thu, 01 Feb 2018 00:00:00 +0000

Given a text and a pattern over an alphabet, the classic exact matching problem searches for all occurrences of the pattern in the text. Unlike exact matching, order-preserving pattern matching (OPPM) considers the relative order of elements, rather t han their real…

SOFSEM 2018

Thu, 01 Feb 2018 00:00:00 +0000

Krems an der Donauで開催された国際会議SOFSEMにおいて研究発表を行いました（1月27日～2月2日）

2018-01-New-Gener-Comput

Mon, 01 Jan 2018 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2017-01-IEEE-BigData

Fri, 01 Dec 2017 00:00:00 +0000

JPHACKS2017 審査員特別賞＆イノベータ認定受賞

Tue, 14 Nov 2017 00:00:00 +0000

2017年11月12日(日)に東京大学武田先端知ビルで行われたJPHACKS2017 Award Dayにおいて、

当研究室の尾池俊之、中島克仁、小林賢、永沼寛章、脇本竜、計５人のチーム「とまと」で開発した作品「麻雀入門者支援アプリ JongHelper 」が

GPW杯デジタルカーリング大会準優勝

Mon, 13 Nov 2017 00:00:00 +0000

修士課程2年の益子直君が作成したプログラム「Parthia」が2017年11月10日(金),11日(土)に箱根セミナーハウスで行われたGPW杯デジタルカーリング大会で準優勝となりました。

2017-gpw-nozaki

Sun, 12 Nov 2017 00:00:00 +0000

2017-11-gpw-ishiwaki

Sat, 11 Nov 2017 00:00:00 +0000

2017-11-gpw-mashiko

Sat, 11 Nov 2017 00:00:00 +0000

2017-11-gpw-ohkawa

Sat, 11 Nov 2017 00:00:00 +0000

GPW 2017

Wed, 01 Nov 2017 00:00:00 +0000

箱根で開催されたゲームプログラミングワークショップ2017において研究発表を行ってきました（11月10日～11月12日）

JPHACKS2017 Hack Day 仙台大会突破

Tue, 24 Oct 2017 00:00:00 +0000

2017年10月21日,22日に東北大学で行われたJPHACKS2017 Hack Day仙台大会において，チームとまとがBest Hack Day Awardを獲得し，東京大学で行われるJPHACKS2017 Award Dayに進出しました．

2017-01-ALT

Sun, 01 Oct 2017 00:00:00 +0000

A ZDD is a directed acyclic graph that represents a family of sets over a fixed universe set. In this paper, we propose an algorithm that learns zero-suppressed binary decision diagrams (ZDDs) usin…

2017-01-CPM

Sat, 01 Jul 2017 00:00:00 +0000

We propose a new indexing structure for parameterized strings, called parameterized position heap. Parameterized position heap is applicable for parameterized pattern matching problem, where the pattern matches a substring of the text if there exists a bijective mapping from the symbols of the pattern to the symbols of the substring. We propose an online construction algorithm of parameterized position heap of a text and show that our algorithm runs in linear time with respect to the text size. We also show that by using parameterized position heap, we can find all occurrences of a pattern in the text in linear time with respect to the product of the pattern size and the alphabet size.

CPM/ICALP 2017

Thu, 01 Jun 2017 00:00:00 +0000

ワルシャワで開催された国際会議CPMおよびICALPに参加し，CPMに研究成果を発表しました（6月4日～14日）

LearnAut workshop on LICS 2017

Thu, 01 Jun 2017 00:00:00 +0000

レイキャビックに開催されたLearnAutに発表しました（6月19日）

2016年度東北大学工学部長賞受賞

Fri, 24 Mar 2017 00:00:00 +0000

学部4年生の中鉢魁三郎君が2016年度東北大学工学部長賞を受賞しました。

2017-01-LATA

Wed, 01 Mar 2017 00:00:00 +0000

We identify the properties of context-free grammars that exactly correspond to the behavior of the dual and primal versions of Clark and Yoshinaka’s distributional learning algorithm and call them the very weak finite context/kernel property. We show that the…

2017-01-WALCOM

Wed, 01 Mar 2017 00:00:00 +0000

The token swapping problem (TSP) and its colored version are reconfiguration problems on graphs. This paper is concerned with the complexity of the TSP and two new variants; namely parallel TSP and parallel colored TSP. For a given graph where each vertex has a…

2017-01-Ann-Math-Artif-Intell

Sun, 01 Jan 2017 00:00:00 +0000

This paper is concerned with a sufficient condition under which a concept class is learnable in Gold’s classical model of identification in the limit

2017-01-SOFSEM

Sun, 01 Jan 2017 00:00:00 +0000

We consider the longest common subsequence (LCS) problem with the restriction that the common subsequence is required to consist of at least k length substrings. First, we show an O(mn) time algorithm for the problem which gives a better worst-case running time than…

2017-01-SOFSEM-2

Sun, 01 Jan 2017 00:00:00 +0000

We introduce new types of approximate palindromes called single-arm-gapped palindromes (SAGPs). A SAGP contains a gap in either its left or right arm, which is in the form of either $$wguc…

SOFSEM 2017

Sun, 01 Jan 2017 00:00:00 +0000

リメリックで開催された国際会議SOFSEMにおいて研究発表を行いました（1月16日～21日）

2016-11-ai

Sat, 05 Nov 2016 00:00:00 +0000

2016-01-SPIRE

Sat, 01 Oct 2016 00:00:00 +0000

Given a set of pattern strings called a dictionary and a text string, dictionary matching is the problem to find the occurrences of the patterns on the text. Dynamic dictionary matching is dictionary matching where patterns may dynamically be inserted into and…

ICGI 2016

Sat, 01 Oct 2016 00:00:00 +0000

オランダのデルフトにて開催された国際会議ICGIのSPiCeワークショップにて研究発表を行ってきました（10月5日～7日）

2016-01-ICFP

Thu, 01 Sep 2016 00:00:00 +0000

PSC 2016

Thu, 01 Sep 2016 00:00:00 +0000

プラハで開催された国際会議PSCにおいて研究発表を行いました（8月29日～31日）

2016-01-PSC

Mon, 01 Aug 2016 00:00:00 +0000

2016-01-IIAI-AAI

Fri, 01 Jul 2016 00:00:00 +0000

2016-01-QBF-SAT

Fri, 01 Jul 2016 00:00:00 +0000

Positional games are a mathematical class of two-player games comprising Tic-tac-toe and its generalizations. We propose a novel encoding of these games into Quantified Boolean Formulas (QBFs) such that a game instance admits a winning strategy for first player if and only if the corresponding formula is true. Our approach improves over previous QBF encodings of games in multiple ways. First, it is generic and lets us encode other positional games, such as Hex. Second, structural properties of positional games together with a careful treatment of illegal moves let us generate more compact instances that can be solved faster by state-of-the-art QBF solvers. We establish the latter fact through extensive experiments. Finally, the compactness of our new encoding makes it feasible to translate realistic game problems. We identify a few such problems of historical significance and put them forward to the QBF community as milestones of increasing difficulty.

DSIR 2016

Fri, 01 Jul 2016 00:00:00 +0000

熊本の国際交流会館にて開催されたAAI DSIRにて研究発表を行ってきました（7月10日～14日）

ICPC 2016

Wed, 01 Jun 2016 00:00:00 +0000

ACM国際大学対抗プログラミングコンテストの国内予選に参加しました（6月24日）

2016-01-DCC

Fri, 01 Apr 2016 00:00:00 +0000

花見 2016

Fri, 01 Apr 2016 00:00:00 +0000

八木山の金剛沢治山の森で花見をしました（4月21日）

2016-03-comp

Mon, 14 Mar 2016 00:00:00 +0000

SOFSEM 2016

Mon, 01 Feb 2016 00:00:00 +0000

国際学会SOFSEMにおいて研究発表を行ってきました (1月22日～1月30日，チェコ)

創造工学研修打ち上げ 2015年度

Mon, 01 Feb 2016 00:00:00 +0000

学部1年生向けの授業、創造工学研修の最終発表の打ち上げとして色々流しました (2月8日)

2016-01-paper-021

Thu, 21 Jan 2016 00:00:00 +0000

2016-01-Discret-Appl-Math

Fri, 01 Jan 2016 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2016-01-Fundam-Informaticae

Fri, 01 Jan 2016 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2016-01-Fundam-Informaticae-2

Fri, 01 Jan 2016 00:00:00 +0000

International audience

2016-01-SOFSEM-Student-Research-Forum-Papers-Pos

Fri, 01 Jan 2016 00:00:00 +0000

2016-01-SOFSEM-Student-Research-Forum-Papers-Pos-2

Fri, 01 Jan 2016 00:00:00 +0000

2016-01-Theor-Comput-Sci

Fri, 01 Jan 2016 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2015-11-paper-022

Sun, 08 Nov 2015 00:00:00 +0000

2015-11-paper-023

Sun, 08 Nov 2015 00:00:00 +0000

2015-11-qbf

Sun, 08 Nov 2015 00:00:00 +0000

ETロボコンCS大会 2015

Sun, 01 Nov 2015 00:00:00 +0000

パシフィコ横浜で開催されたETロボコンチャンピオンシップ大会へJoker艮が参加しました（11月18日～11月19日）

GPW 2015

Sun, 01 Nov 2015 00:00:00 +0000

軽井沢で開催されたゲームプログラミングワークショップ2015において研究発表を行ってきました（11月6日～11月8日）

PIAMSE 2015

Thu, 01 Oct 2015 00:00:00 +0000

インドネシアのバリで開催されたPIAMSEにおいて研究発表を行ってきました（9月29日～10月2日）

芋煮 2015

Thu, 01 Oct 2015 00:00:00 +0000

毎年恒例の芋煮を行いました（10月14日）

ETロボコン2015東北地区大会イノベーター部門総合優勝東北経済産業局長賞受賞

Mon, 14 Sep 2015 00:00:00 +0000

2015年9月12日（土）に岩手県民情報交流センター（アイーナ）で行われたETロボコン2015東北地区大会において、

チーム「Joker艮」が

イノベーター部門総合優勝東北経済産業局長賞を受賞しました。

2015-09-paper-025

Tue, 01 Sep 2015 00:00:00 +0000

DubeとBeaudoinによって2010年に考案された無ひずみデータ圧縮法である部分文字列数え上げ圧縮法に対し，金井と横尾はBurrows-Wheeler変換行列をうまく利用した効率的な実装方法を提案した．本論文は，この実装方法を一般化し，(1)バイト指向情報源に対してフェーズの区別を明示的に導入することで圧縮率を高める，(2) バイナリ文字列のみならず多値アルファベットの文字列をそのまま取り扱える，という２方向への拡張を示す．

COMP研 in 信州大 2015

Tue, 01 Sep 2015 00:00:00 +0000

信州大学にて開催されたCOMP研にて研究発表を行ってきました（9月1日）

ETロボコン東北地区大会 2015

Tue, 01 Sep 2015 00:00:00 +0000

いわて県民情報交流センターにて開催されたETロボコン東北大会にJoker艮が参加しました（9月12日）

ETロボコン東北地区試走会 2015

Sat, 01 Aug 2015 00:00:00 +0000

東北電子専門学校にて開催されたETロボコン試走会にJoker艮が参加してきました（8月29日）

2015-01-MOL

Wed, 01 Jul 2015 00:00:00 +0000

ICPC国内予選 2015

Mon, 01 Jun 2015 00:00:00 +0000

ACM国際大学対抗プログラミングコンテストの国内予選に篠原研究室から7チームが参加しました（6月26日）

しらすパーティー 2015

Fri, 01 May 2015 00:00:00 +0000

今年も静岡から新鮮なしらすと桜えびが届きました（5月14日）

花見 2015

Fri, 01 May 2015 00:00:00 +0000

塩竈神社で花見をしてきました（4月29日）

2015-01-LATA

Sun, 01 Mar 2015 00:00:00 +0000

Approaches based on the idea generically called distributional learning have been making great success in the algorithmic learning of context-free languages and their extensions. We in this paper show that conjunctive grammars are also learnable by a distributional…

STRセミナー2015

Sun, 01 Mar 2015 00:00:00 +0000

大分県別府市で開催されたSTRセミナーに参加し、M1の柏葉君、B4の上木君、海津君、佐久間君、佐藤君が発表を行いました。（3月18日～20日）

恵方巻 2015

Sun, 01 Feb 2015 00:00:00 +0000

みんなで恵方巻きを食べました。今年は恵方は西南西です。（2月3日）

創造工学研修打ち上げ 2014年度

Sun, 01 Feb 2015 00:00:00 +0000

学部1年生向けの創造工学研修の打ち上げをしました。今年はたこ焼きとお好み焼きと生春巻きです。（2月9日）

冬のLAシンポジウム in 京都 2015

Sun, 01 Feb 2015 00:00:00 +0000

京都大学で行われた冬のLAシンポジウムにてM2の佐藤雄介君とB4の上木庸平君が研究発表を行いました。（1月28日～30日）

2015-01-LA-ueki

Fri, 30 Jan 2015 00:00:00 +0000

LA2015-winter

Fri, 30 Jan 2015 00:00:00 +0000

桂敬史くん（博士3年）がSOFSEM2015でBest Student Poster Awardを受賞

Thu, 29 Jan 2015 00:00:00 +0000

博士課程後期3年の桂敬史くんが2015年1月24日-29日にチェコで開催された国際会議SOFSEM 2015 （41st International Conference on Current Trends in Theory and Practice of Computer Science）において，Best Student Poster Awardを受賞しました．

SOFSEM2015

Mon, 26 Jan 2015 00:00:00 +0000

A multi-set of $N$ strings of length $n$ is called a multi-track string. The permuted pattern matching is the problem that given two multi-track strings $T = { t_1, \ldots, t_N }$ of length $n$ and $P = {p_1, \ldots, p_{N}}$ of length $m$, outputs all positions $i$ such that ${p_1 \ldots, p_N} = {t_1[i : i + m_1], \ldots, t_N[i:i+m_1]}$. We propose two newi ndexing structures for multi-track stings. One is a time-efficient structure for $T$ that needs $O(nN)$ space and enables us to solve the problem in $O(m^2 N+occ)$ time, where $occ$ is the number of occurrences of the pattern $P$ in the text $T$. The other is memory-e cient, it requires only $O(n)$ space, whereas the matching consumes $O(m^2 N^2 + occ)$ time. We show that both of them can be constructed in $O(nN)$ time.

SOFSEM 2015

Sun, 25 Jan 2015 00:00:00 +0000

チェコで開催された国際会議SOFSEM2015においてD3の桂敬史君がポスター発表を行いました。（1月24日～29日）

2015-01-FG

Thu, 01 Jan 2015 00:00:00 +0000

We study tree-generating almost linear second-order ACGs that admit bounded nonlinearity either on the context side or on the substructure side, and give distributional learning algorithms for them.

2015-01-Inf-Comput

Thu, 01 Jan 2015 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

アルゴリズム研究会 in 名古屋 2015

Thu, 01 Jan 2015 00:00:00 +0000

愛知県名古屋市で開催されたアルゴリズム研究会にてM2の佐藤雄介君が研究発表を行いました。（1月13日～14日）

駅伝大会 2014

Mon, 01 Dec 2014 00:00:00 +0000

今年は，駅伝史上初の雨天延期により，日程が変更になったためおでんではなくカレーです。（12月7日）

ETロボコンチャンピオンシップ大会 2014

Sat, 01 Nov 2014 00:00:00 +0000

横浜市のパシフィコ横浜で開催されたETロボコンチャンピオンシップ大会にJoker艮とAce艮が参加しました。（11月19日～20日）

KDIR 2014

Wed, 01 Oct 2014 00:00:00 +0000

イタリアのローマで開催された国際学会KDIRにて佐藤雄介君が研究発表を行いました。（10月21日～24日）

芋煮 2014

Wed, 01 Oct 2014 00:00:00 +0000

毎年恒例の芋煮を行いました。（10月9日）

野球大会1回戦 2014

Wed, 01 Oct 2014 00:00:00 +0000

電気系の野球大会1回戦にて見事勝利しました。（10月8日）

ETロボコン2014東北地区大会アーキテクト部門総合優勝東北経済産業局長賞受賞

Mon, 22 Sep 2014 00:00:00 +0000

2014年9月20日（土）に岩手県民情報交流センター（アイーナ）で行われたETロボコン2014東北地区大会において、

チーム「Ace艮」が

アーキテクト部門総合優勝東北経済産業局長賞を受賞しました。

ETロボコン2014東北地区大会デベロッパー部門アドバンストクラス総合優勝

Mon, 22 Sep 2014 00:00:00 +0000

2014年9月20日（土）に岩手県民情報交流センター（アイーナ）で行われたETロボコン2014東北地区大会において、チーム「Joker艮」が

競技部門優勝総合部門優勝を受賞しました。

2014-09-paper-029

Tue, 02 Sep 2014 00:00:00 +0000

ETロボコン2014東北地区試走会2

Mon, 01 Sep 2014 00:00:00 +0000

岩手県盛岡市で行われたETロボコン東北地区第2回試走会にJoker艮とAce艮が参加しました。（8月30日）

ETロボコン2014東北地区大会

Mon, 01 Sep 2014 00:00:00 +0000

岩手県盛岡市で行われたETロボコン2014東北地区大会にJoker艮とAce艮が参加しました。（9月20日）

新1号館移転

Mon, 25 Aug 2014 00:00:00 +0000

2014年8月22日に、新1号館への移転が完了しました．

新1号館では篠原研究室は6階になります．これからも、どうぞよろしくお願いします．

オープンキャンパス 2014

Fri, 01 Aug 2014 00:00:00 +0000

今年は新1号館でのオープンキャンパスを開催することができて、とても盛況でした。（7月30日,31日）

2014-07-paper-030

Thu, 17 Jul 2014 00:00:00 +0000

2014-07-paper-031

Thu, 17 Jul 2014 00:00:00 +0000

ETロボコン2014東北地区試走会1

Tue, 01 Jul 2014 00:00:00 +0000

岩手県盛岡市で行われたETロボコン東北地区第1回試走会にJoker艮が参加しました。（7月26日）

ICPC国内予選 2014

Tue, 01 Jul 2014 00:00:00 +0000

篠原研では5チームが予選に参加しました。（7月11日）

夏のLAシンポジウム in 岩国 2014

Tue, 01 Jul 2014 00:00:00 +0000

山口県岩国市で開催された夏のLAシンポジウムにてM2の佐藤雄介君とM1の石黒裕也君が研究発表を行いました。（7月17日～19日）

しらすパーティー 2014

Thu, 01 May 2014 00:00:00 +0000

静岡県産の新鮮なしらすが届きました。（5月9日）

花見 2014

Tue, 01 Apr 2014 00:00:00 +0000

毎年恒例の花見です。今年は一目千本桜がある大河原で行いました。（4月15日）

2013年度工学部長賞受賞

Mon, 31 Mar 2014 00:00:00 +0000

学部4年生の轟奨太君が2013年度東北大学工学部長賞を受賞しました。

2014-01-DCC

Sat, 01 Mar 2014 00:00:00 +0000

2014-01-ICAART-1

Sat, 01 Mar 2014 00:00:00 +0000

Most existing reinforcement learning algorithms require many trials until they obtain optimal policies. In this study, we apply transfer learning to reinforcement learning to realize greater efficiency. We propose a new algorithm called TR-MAX, based on the R-MAX algorithm. TR-MAX transfers the transition and reward probabilities from a source task to a target task as prior knowledge. We theoretically analyze the sample complexity of TR-MAX. Moreover, we show that TR-MAX performs much better in practice than R-MAX in maze tasks.

ICAART 2014

Sat, 01 Mar 2014 00:00:00 +0000

国際学会ICAARTにおいて研究発表を行いました。（3月6日～8日，フランス：アンジェ）

STRセミナー2014

Sat, 01 Mar 2014 00:00:00 +0000

STRセミナーにて発表を行いました。（3月18日～19日）

SOFSEM 2014

Sat, 01 Feb 2014 00:00:00 +0000

国際学会SOFSEMにおいて研究発表を行いました。（1月25日～30日，スロバキア）

創造工学打ち上げ2013年度

Sat, 01 Feb 2014 00:00:00 +0000

学部1年生対象の授業、創造工学研修の打ち上げを行いました。（2月10日）

2014-01-Discret-Appl-Math

Wed, 01 Jan 2014 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2014-01-IEEE-Trans-Smart-Grid

Wed, 01 Jan 2014 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2014-01-ISAIM

Wed, 01 Jan 2014 00:00:00 +0000

2014-01-KDIR

Wed, 01 Jan 2014 00:00:00 +0000

2014-01-Mach-Learn

Wed, 01 Jan 2014 00:00:00 +0000

Natural languages require grammars beyond context-free for their description. Here we extend a family of distributional learning algorithms for context-fre

2014-01-Mach-Learn-2

Wed, 01 Jan 2014 00:00:00 +0000

This paper describes several collapsed Bayesian methods, which work by first marginalizing out transition probabilities, for inferring several kinds of pro

2014-01-SOFSEM

Wed, 01 Jan 2014 00:00:00 +0000

Given two sets of strings and a similarity function on strings, similarity joins attempt to find all similar pairs of strings from each respective set. In this paper, we focus on similarity joins with respect to the edit distance, and propose a new metric called the…

2014-01-Theory-Comput-Syst

Wed, 01 Jan 2014 00:00:00 +0000

Seki et al. (Theor. Comput. Sci. 88(2):191–229, 1991) showed that every m-multiple context-free language L is weakly 2m-iterative in the sense that e

2014-06-LACL

Wed, 01 Jan 2014 00:00:00 +0000

We define an algebraic structure, Paired Complete Idempotent Semirings (pcis), which are appropriate for defining a denotational semantics for multiple context-free grammars of dimension 2 (2-mcfg). We demonstrate that homomorphisms of this structure will induce…

2013-12-paper-032

Sat, 21 Dec 2013 00:00:00 +0000

COMP研 in 沖縄 2013

Sun, 01 Dec 2013 00:00:00 +0000

コンピュテーション研究会にて研究発表を行いました。（12月20日～21日，沖縄：那覇）

駅伝大会 2013

Sun, 01 Dec 2013 00:00:00 +0000

今年は去年よりもだいぶ頑張りました。（12月1日）

忘年会 2013

Sun, 01 Dec 2013 00:00:00 +0000

配属が決まった3年生を迎えての忘年会です。（12月17日）

ETロボコン2013チャンピオンシップ大会競技部門準優勝情報処理学会若手奨励賞受賞

Fri, 22 Nov 2013 00:00:00 +0000

2013年11月20日（水）にパシフィコ横浜で行われたETロボコン2013チャンピオンシップ大会において、チーム「Joker 艮」がデベロッパー競技部門準優勝を獲得しました．また、学生の中で特に優秀な成績を残したチームに贈られる、情報処理学会若手奨励賞を受賞しました．

2013-11-paper-033

Wed, 13 Nov 2013 00:00:00 +0000

2013-11-p

Fri, 08 Nov 2013 00:00:00 +0000

ETロボコンチャンピオンシップ大会 2013

Fri, 01 Nov 2013 00:00:00 +0000

ETロボコンチャンピオンシップ大会に参加しました。（11月20日～21日，横浜）

GPW 2013

Fri, 01 Nov 2013 00:00:00 +0000

GPWにおいて研究発表を行いました。（11月8日～10日，神奈川：箱根）

IBIS 2013

Fri, 01 Nov 2013 00:00:00 +0000

IBISにおいてポスター発表を行いました。（11月10日～13日，東京）

2013-10-paper-034

Fri, 18 Oct 2013 00:00:00 +0000

芋煮 2013

Tue, 01 Oct 2013 00:00:00 +0000

秋の恒例行事、芋煮を行いました。（10月3日）

野球大会 2013

Tue, 01 Oct 2013 00:00:00 +0000

4年生の轟くんが参加しました。（10月4日）

ETロボコン2013東北地区大会 3部門入賞

Wed, 25 Sep 2013 00:00:00 +0000

2013年9月23日（月）にいわて県民情報交流センター（アイーナ）で行われたETロボコン2013東北地区大会において、チーム「Joker 艮」が

第3回相磯秀夫杯 FPGAデザインコンテスト準優勝

Fri, 20 Sep 2013 00:00:00 +0000

奥田　遼介（システム情報科学専攻篠原研究室 M2）が所属するチームSnowdropが「第3回相磯秀夫杯 FPGAデザインコンテスト」で第2位入賞となりました．

2013-09-sat

Thu, 12 Sep 2013 00:00:00 +0000

2013-01-PSC

Sun, 01 Sep 2013 00:00:00 +0000

ETロボコン東北地区公式試走会 2013

Sun, 01 Sep 2013 00:00:00 +0000

東北地区大会に向けての試走会に参加しました。（8月31日，岩手：盛岡）

ETロボコン東北地区大会 2013

Sun, 01 Sep 2013 00:00:00 +0000

ETロボコン東北地区大会に参加しました。（9月23日，岩手：盛岡）

OR学会 2013

Sun, 01 Sep 2013 00:00:00 +0000

オペーレションズリサーチ学会において研究発表を行いました。（9月11日～12日，徳島）

PSC 2013

Sun, 01 Sep 2013 00:00:00 +0000

国際会議PSCにおいて研究発表を行いました。（9月5日～7日，チェコ：プラハ）

BBQ 2013

Thu, 01 Aug 2013 00:00:00 +0000

夏の初めのバーベキューです。（8月3日）

オープンキャンパス 2013

Thu, 01 Aug 2013 00:00:00 +0000

今年度、篠原研は満足度・訪問数ともにNO.1でした。（7月30日～31日）

CODE VS 2.1決勝戦第3位

Fri, 26 Jul 2013 00:00:00 +0000

奥田　遼介さん（システム情報科学専攻篠原研究室 M2）が「プログラマ世界一決定戦 - CODE VS 2.1」の決勝トーナメントで第3位

博士課程前期2年奥田遼介，小松智希と，研究室OBの草野一彦が，「プログラマ世界一決定戦

2013-07-paper-037

Wed, 17 Jul 2013 00:00:00 +0000

LTC 2013

Mon, 01 Jul 2013 00:00:00 +0000

国際会議LTCにおいて研究発表を行いました。（7月7日～12日，ラトビア：リガ）

SIGMOD 2013

Mon, 01 Jul 2013 00:00:00 +0000

国際会議SIGMODのプログラミングコンテストで発表を行いました。（6月22日～27日，アメリカ：ニューヨーク）

飲み会 2013

Mon, 01 Jul 2013 00:00:00 +0000

工学セミナーとかが終わったので飲み会です。（7月2日）

夏のLAシンポジウム in 福岡 2013

Mon, 01 Jul 2013 00:00:00 +0000

LAシンポジウムにおいて研究発表を行いました。（7月16日～18日，福岡：志賀島）

オクトーバーフェスト 2013

Sat, 01 Jun 2013 00:00:00 +0000

（6月12日）

2013-04-n-57-2-03696

Wed, 24 Apr 2013 00:00:00 +0000

2013-04-paper-038

Wed, 24 Apr 2013 00:00:00 +0000

ACM SIGMOD 2013 Programming Contest Finalist入り

Mon, 22 Apr 2013 00:00:00 +0000

2013年3月1日から2013年4月15日にかけてオンライン上で行なわれたACM SIGMOD 2013 Programming Contestにて奥田遼介(M2)，小松智希(M2)，桂敬史(D2) （大友雄平(OB)）がチームmofumofuとして参加し，Finalist入りを果たしました．

AAAC 2013

Mon, 01 Apr 2013 00:00:00 +0000

松島で開催された国際会議AAACに参加しました。（4月19日～21日）

COMP研 in 神戸 2013

Mon, 01 Apr 2013 00:00:00 +0000

コンピュテーション研究会にて研究発表を行いました。（4月24日）

花見 2013

Mon, 01 Apr 2013 00:00:00 +0000

（4月16日）

第1回 SECCON CTF 全国大会第4位

Tue, 26 Feb 2013 00:00:00 +0000

2013年2月23日（土）～24日（日）に東京電機大学で開催された第1回 SECCON CTF 全国大会に、草野一彦、桂敬史、庄崎大輔、奥田遼介がチームmofuppとして参加し、第4位を獲得しました。

学生プログラマ日本一決定戦CODEVS2.0 優勝

Mon, 28 Jan 2013 00:00:00 +0000

2013年1月19日（土）に東京都港区ニコファーレで開催された学生プログラマ日本一決定戦CODEVS2.0で小松智希が優勝しました．

CODEBOUT 準優勝

Fri, 18 Jan 2013 00:00:00 +0000

CODEBOUTに奥田，小松がチーム「MOFU Cube」として参加し，準優勝しました．CODEBOUTは2014年卒の学生限定のプログラミングコンテストです．「MOFU Cube」は500点満点のコンテストで445点を獲得しました．

2013-01-SOFSEM

Tue, 01 Jan 2013 00:00:00 +0000

We propose a new variant of pattern matching on a multi-set of strings, or multi-tracks, called permuted-matching, that looks for occurrences of a multi-track pattern of length m with M tracks, in a multi-track text of length n with N tracks over Σ. We show that…

2013-10-ALT

Tue, 01 Jan 2013 00:00:00 +0000

In recent years different interesting subclasses of cfls have been found to be learnable by techniques generically called distributional learning. The theoretical study on the exact learning of cfls by those techniques under different learning scheme is now quite…

SECCON 横浜大会（関東地区）CTF 準優勝

Mon, 24 Dec 2012 00:00:00 +0000

2012年12月22日（土）に横浜市の情報セキュリティ大学院大学で開催されたSECCON（SECurity CONtest）横浜大会CTFに，草野，桂，庄崎，奥田がチームmofuppとして参加し，準優勝を果たしました．

2012-12-paper-040

Mon, 10 Dec 2012 00:00:00 +0000

2012-12-et

Sat, 01 Dec 2012 00:00:00 +0000

2012-12-satori2

Sat, 01 Dec 2012 00:00:00 +0000

COMP研 in 九州 2012

Sat, 01 Dec 2012 00:00:00 +0000

（12月10日）

カキ小屋 2012

Sat, 01 Dec 2012 00:00:00 +0000

松島のカキ小屋へ行きました。（12月4日）

忘年会 2012

Sat, 01 Dec 2012 00:00:00 +0000

2012年忘年会を行いました。（12月19日）

ETロボコンチャンピオンシップ大会TOPPERS賞受賞

Mon, 19 Nov 2012 00:00:00 +0000

2012年11月14日（水）にパシフィコ横浜で行われたETロボコン2012チャンピオンシップ大会に「Joker艮」が出場しました。リアルタイムOSの特徴を生かしたモデル開発を行ったチームに対して授与される「Toppers賞」を受賞しました

ETロボコンチャンピオンシップ大会 2012

Thu, 01 Nov 2012 00:00:00 +0000

ETロボコンチャンピオンシップ大会に参加しました。（11月14日～15日）

駅伝大会 2012

Thu, 01 Nov 2012 00:00:00 +0000

毎年恒例電気系駅伝大会に参加しました。（11月17日）

2012-10-paper-043

Wed, 31 Oct 2012 00:00:00 +0000

2012-01-SPIRE

Mon, 01 Oct 2012 00:00:00 +0000

A run (also called maximal repetition) in a word is a non-extendable repetition. Finding the maximum number ρ(n) of runs in a string of length n is a challenging problem. Although it is known that ρ(n) ≤ 1.029n for any n and there exists…

SPIRE 2012

Mon, 01 Oct 2012 00:00:00 +0000

（10月21日）

芋煮 2012

Mon, 01 Oct 2012 00:00:00 +0000

秋の恒例行事芋煮会を行いました。（10月10日）

2012-09-paper-044

Mon, 03 Sep 2012 00:00:00 +0000

ETロボコン東北地区大会総合優勝

Mon, 03 Sep 2012 00:00:00 +0000

2012年9月22日（土）にいわて県民情報交流センター（アイーナ）で行われたETロボコン2012東北地区大会において、チーム「Joker 艮」が

2012-01-ICGI

Sat, 01 Sep 2012 00:00:00 +0000

Semilinearity is widely held to be a linguistic invariant but, controversially, some linguistic phenomena in languages like Old Georgian and Yoruba seem to violate this constraint. In this paper we…

2012-01-ICGI-2

Sat, 01 Sep 2012 00:00:00 +0000

A Bayesian manner which marginalizes transition probabilities can be generally applied to various kinds of probabilistic finite state machine models. Based on such a Bayesian manner, we implemented…

2012-01-TAG

Sat, 01 Sep 2012 00:00:00 +0000

Ryo Yoshinaka. Proceedings of the 11th International Workshop on Tree Adjoining Grammars and Related Formalisms (TAG+11). 2012.

ETロボコン東北地区公式試走会2 2012

Sat, 01 Sep 2012 00:00:00 +0000

東北地区大会に向けて試走会に参加しました。（9月9日, 盛岡）

ETロボコン東北地区大会 2012

Sat, 01 Sep 2012 00:00:00 +0000

ETロボコン東北地区大会に参加しました。（9月22日,盛岡）

STRセミナー北海道 2012

Sat, 01 Sep 2012 00:00:00 +0000

STRセミナーにて研究発表を行いました。（9月10日～9月12日,北海道河東郡音更町）

ETロボコン東北地区公式試走会1 2012

Wed, 01 Aug 2012 00:00:00 +0000

東北地区大会に向けて試走会に参加しました。（8月6日, 盛岡）

オープンキャンパス 2012

Wed, 01 Aug 2012 00:00:00 +0000

2012年度のオープンキャンパスも盛況でした。（7月30日、7月31日）

オスカーさん送別会 2012

Wed, 01 Aug 2012 00:00:00 +0000

(8月8日)

2012-07-paper-045

Fri, 13 Jul 2012 00:00:00 +0000

ACM/ICPC国内予選突破

Mon, 09 Jul 2012 00:00:00 +0000

ACM/ICPC2012国内予選に参加し，チームmofu.txt(大友，成澤（乾・岡崎研），鈴木（外山・青戸研））が予選を突破しました．

ICPC国内予選 2012

Sun, 01 Jul 2012 00:00:00 +0000

ICPC国内予選に参加し、mofu.txtがアジア予選に進みました。（7月6日）

ゲーム情報学研究会 2012

Sun, 01 Jul 2012 00:00:00 +0000

小松さんが論文を発表しました。（7月13日）

花見 2012

Sun, 01 Apr 2012 00:00:00 +0000

新しいメンバーを迎えて1年ぶりの花見を行いました。（4月24日）

STRセミナー島原 2012

Thu, 01 Mar 2012 00:00:00 +0000

STRセミナーにて研究発表を行いました。（3月6日～3月8日, 島原）

2012-01-ICAART-1

Wed, 01 Feb 2012 00:00:00 +0000

SSML 2012

Wed, 01 Feb 2012 00:00:00 +0000

国際学会ICAARTのSpecial Session on Machine Learningにて研究発表を行いました。（2月6日～2月8日, ポルトガル）

2012-01-Algorithms

Sun, 01 Jan 2012 00:00:00 +0000

Link puzzles involve finding paths or a cycle in a grid that satisfy given local and global properties. This paper proposes algorithms that enumerate solutions and instances of two link puzzles, Slitherlink and Numberlink, by zero-suppressed binary decision diagrams (ZDDs). A ZDD is a compact data structure for a family of sets provided with a rich family of set operations, by which, for example, one can easily extract a subfamily satisfying a desired property. Thanks to the nature of ZDDs, our algorithms offer a tool to assist users to design instances of those link puzzles.

2012-01-High-Order-Symb-Comput

Sun, 01 Jan 2012 00:00:00 +0000

We propose an application of programming language techniques to lossless data compression, where tree data are compressed as functional programs that gener

2012-01-Inf-Process-Lett

Sun, 01 Jan 2012 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2012-03-LATA

Sun, 01 Jan 2012 00:00:00 +0000

Recently several “distributional learning algorithms” have been proposed and have made great success in learning different subclasses of context-free grammars. The distributional learning models and exploits the relation between strings and contexts that…

2011-11-paper-046

Sat, 05 Nov 2011 00:00:00 +0000

ETロボコンCS大会 2011

Tue, 01 Nov 2011 00:00:00 +0000

パシフィコ横浜で行われたETロボコンチャンピオンシップ大会に参加してきました。（11月16日～17日）

駅伝大会 2011

Tue, 01 Nov 2011 00:00:00 +0000

（11月26日）

2011-01-ALT

Sat, 01 Oct 2011 00:00:00 +0000

This paper demonstrates how existing distributional learning techniques for context-free grammars can be adapted to simple context-free tree grammars in a straightforward manner once the necessary notions and properties for string languages have been redefined for…

芋煮 2011

Sat, 01 Oct 2011 00:00:00 +0000

（10月5日）

列挙学校 2011

Sat, 01 Oct 2011 00:00:00 +0000

（9月28日～30日）

2011-01-ISCIS

Thu, 01 Sep 2011 00:00:00 +0000

Angluin (1980) showed that there is a consistent and conservative learner for the class of non-erasing pattern languages; however, most of these learners are NP-hard. In the current work, the complexity of consistent polynomial time learners for the class of…

ETロボコン東北地区大会 2011

Thu, 01 Sep 2011 00:00:00 +0000

競技部門、モデル部門、総合部門の三冠制覇でチャンピオンシップ出場権を獲得しました。（9月3日, 盛岡）

2011-08-satori

Thu, 04 Aug 2011 00:00:00 +0000

2011-08-vldc

Thu, 04 Aug 2011 00:00:00 +0000

2011-01-PSC

Mon, 01 Aug 2011 00:00:00 +0000

ETロボコン東北地区公式試走会2 2011

Mon, 01 Aug 2011 00:00:00 +0000

東北地区大会に向けて試走会に参加しました。（8月20日, 盛岡）

Richardさん、よくぞきてくれました飲み会 2011

Mon, 01 Aug 2011 00:00:00 +0000

（8月9日）

いろいろ打ち上げ飲み 2011

Mon, 01 Aug 2011 00:00:00 +0000

オープンキャンパス等いろいろなイベントが終了したので打ち上げをしました。（7月29日）

人工知能基本問題研究会 2011

Mon, 01 Aug 2011 00:00:00 +0000

人工知能基本問題研究会で研究発表を行いました。（8月3日～8月6日, 釧路）

2011-07-paper-049

Tue, 19 Jul 2011 00:00:00 +0000

2011-01-Developments-in-Language-Theory

Fri, 01 Jul 2011 00:00:00 +0000

Recent studies on grammatical inference have demonstrated the benefits of “distributional learning” for learning context-free and context-sensitive languages. Distributional learning models and exploits the relation between strings and contexts in the…

2011-01-LACL

Fri, 01 Jul 2011 00:00:00 +0000

Minimalist grammars (MGs) constitute a mildly context-sensitive formalism when being equipped with a particular locality condition (LC), the shortest move condition. In this format MGs define the same class of derivable string languages as…

2011-01-LACL-2

Fri, 01 Jul 2011 00:00:00 +0000

Recent studies on grammatical inference have demonstrated the benefits of the learning strategy called “distributional learning” for context-free and multiple context-free languages. This paper gives a comprehensive view of distributional learning of…

オープンキャンパス 2011

Fri, 01 Jul 2011 00:00:00 +0000

東北大学オープンキャンパスで展示を行いました。（7月27日～7月28日）

夏のLAシンポジウム 2011

Fri, 01 Jul 2011 00:00:00 +0000

夏のLAシンポジウム2011で研究発表を行いました。(7月19日～21日，浜松)

ICPC国内予選 2011

Wed, 01 Jun 2011 00:00:00 +0000

ICPC国内予選に参加しました。（6月24日）

粉ものの日 2011

Wed, 01 Jun 2011 00:00:00 +0000

粉ものを料理して食べる，粉ものの日を開催しました。（6月16日)

3号館引っ越し

Sun, 01 May 2011 00:00:00 +0000

東日本大震災により、研究室のある１号館が被災し、３号館へ引っ越ししました。（4月）

ITA 2011

Tue, 01 Mar 2011 00:00:00 +0000

（2月28日～3月1日，シンガポール）

M2追いコン 2011

Tue, 01 Feb 2011 00:00:00 +0000

（2月16日，仙台某所）

STRセミナー 2011

Tue, 01 Feb 2011 00:00:00 +0000

（2月24日～26日，作並温泉）

2011-01-Theor-Comput-Sci

Sat, 01 Jan 2011 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

ACM-ICPCアジア地区予選 2010

Wed, 01 Dec 2010 00:00:00 +0000

（12月11日～13日，東京）

ETロボコンチャンピオンシップ大会 2010

Wed, 01 Dec 2010 00:00:00 +0000

（12月1日～3日，横浜）

光のページェント 2010

Wed, 01 Dec 2010 00:00:00 +0000

（12月，仙台，おまけページ）

GPW 2010

Mon, 01 Nov 2010 00:00:00 +0000

研究発表（11月12日～14日，箱根）

駅伝大会 2010

Mon, 01 Nov 2010 00:00:00 +0000

15kmを10人のランナーがタスキで繋ぐ伝統行事（11月13日）

芋煮会 2010

Fri, 01 Oct 2010 00:00:00 +0000

新留学生Richardさんを迎えて，最も重要なイベントを開催！（10月8日）

2010-09-paper-050

Mon, 20 Sep 2010 00:00:00 +0000

2010-09-paper-051

Mon, 20 Sep 2010 00:00:00 +0000

2010-01-PSC

Wed, 01 Sep 2010 00:00:00 +0000

2010-01-PSC-2

Wed, 01 Sep 2010 00:00:00 +0000

2010-01-PSC-3

Wed, 01 Sep 2010 00:00:00 +0000

ETロボコン試走会2 2010

Wed, 01 Sep 2010 00:00:00 +0000

東北地区大会に向けて最終調整！（9月17日，盛岡）

ETロボコン東北地区大会 2010

Wed, 01 Sep 2010 00:00:00 +0000

競技部門1位，特別賞，総合部門4位，チャンピオンシップ大会出場権獲得！（9月23日，盛岡）

Felixさん送別会 2010

Wed, 01 Sep 2010 00:00:00 +0000

ドイツからの留学生Felixさんを送る会（9月24日）

FIT 2010

Wed, 01 Sep 2010 00:00:00 +0000

学会発表（9月7日～9日，福岡）

PSC 2010

Wed, 01 Sep 2010 00:00:00 +0000

学会発表（8月29日～9月2日，プラハ）

花火大会 2010

Sun, 01 Aug 2010 00:00:00 +0000

青葉山から撮影した写真を公開（8月5日）

ETロボコン試走会1 2010

Thu, 01 Jul 2010 00:00:00 +0000

篠原研はチーム名「Joker 艮」でETロボコン2010に初参戦！（7月17日，盛岡）

オープンキャンパス 2010

Thu, 01 Jul 2010 00:00:00 +0000

人間とコンピュータの知能対決！（7月27日～29日）

麺パーティ 2010

Thu, 01 Jul 2010 00:00:00 +0000

乾研のカレーパーティに対抗したもの．麺なら何でもOK！（7月9日）

カレーパーティ 2010

Tue, 01 Jun 2010 00:00:00 +0000

乾研の手作りカレーを堪能（6月22日）

秋田小旅行 2010

Tue, 01 Jun 2010 00:00:00 +0000

（オフショット）（6月19日）

2010-01-AAMAS

Sat, 01 May 2010 00:00:00 +0000

AAMAS 2010

Sat, 01 May 2010 00:00:00 +0000

学会発表（5月10日～14日，トロント）

SACSIS 2010

Sat, 01 May 2010 00:00:00 +0000

学会発表（5月27日～28日，奈良）

テニス大会 2010

Sat, 01 May 2010 00:00:00 +0000

研究室対抗のスポーツ大会（5月中旬）

青葉まつり 2010

Sat, 01 May 2010 00:00:00 +0000

（オフショット）（5月16日）

2010-04-paper-052

Thu, 22 Apr 2010 00:00:00 +0000

2010-04-paper-053

Thu, 22 Apr 2010 00:00:00 +0000

花見 2010

Thu, 01 Apr 2010 00:00:00 +0000

年度始めのお約束行事．今年は絶好の花見日和！（4月25日）

2010-03-paper-054

Sat, 20 Mar 2010 00:00:00 +0000

2010-03-paper-055

Sat, 20 Mar 2010 00:00:00 +0000

2010-03-paper-056

Tue, 09 Mar 2010 00:00:00 +0000

2010-01-Chic-J-Theor-Comput-Sci

Fri, 01 Jan 2010 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2010-01-FG

Fri, 01 Jan 2010 00:00:00 +0000

We present an algorithm for the inference of some Multiple Context-Free Grammars from Membership and Equivalence Queries, using the Minimally Adequate Teacher model of Angluin. This is an extension of the congruence based methods for learning some Context-Free…

2009-11-paper-057

Sun, 22 Nov 2009 00:00:00 +0000

2009-11-paper-058

Sat, 14 Nov 2009 00:00:00 +0000

2009-01-PSC

Tue, 01 Sep 2009 00:00:00 +0000

2009-07-paper-059

Mon, 20 Jul 2009 00:00:00 +0000

2009-07-paper-060

Mon, 20 Jul 2009 00:00:00 +0000

2009-07-paper-061

Mon, 20 Jul 2009 00:00:00 +0000

2009-01-COLT

Mon, 01 Jun 2009 00:00:00 +0000

2009-05-cell-be

Thu, 28 May 2009 00:00:00 +0000

2009-01-AAMAS-2

Fri, 01 May 2009 00:00:00 +0000

2009-01-LATA

Wed, 01 Apr 2009 00:00:00 +0000

We present a new series of run-rich strings, and give a new lower bound 0.94457567 of the maximum number of runs in a string. We also introduce the general conjecture about a asymptotic behavior of the numbers of runs in the strings defined by any recurrence formula,…

2009-03-paper-064

Fri, 20 Mar 2009 00:00:00 +0000

2009-03-paper-063

Mon, 02 Mar 2009 00:00:00 +0000

2009-02-o-nloglogn

Sun, 01 Feb 2009 00:00:00 +0000

2009-02-paper-065

Sun, 01 Feb 2009 00:00:00 +0000

2009-02-paper-066

Sun, 01 Feb 2009 00:00:00 +0000

2009-02-paper-068

Sun, 01 Feb 2009 00:00:00 +0000

2009-01-Algorithms

Thu, 01 Jan 2009 00:00:00 +0000

We consider grammar-based text compression with longest first substitution (LFS), where non-overlapping occurrences of a longest repeating factor of the input text are replaced by a new non-terminal symbol. We present the first linear-time algorithm for LFS. Our algorithm employs a new data structure called sparse lazy suffix trees. We also deal with a more sophisticated version of LFS, called LFS2, that allows better compression. The first linear-time algorithm for LFS2 is also presented.

2009-01-CATS

Thu, 01 Jan 2009 00:00:00 +0000

2009-01-IEICE-Trans-Inf-Syst

Thu, 01 Jan 2009 00:00:00 +0000

Access full-text academic articles: J-STAGE is an online platform for Japanese academic journals.

2009-01-Inf-Process-Lett

Thu, 01 Jan 2009 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2009-01-Int-J-Found-Comput-Sci

Thu, 01 Jan 2009 00:00:00 +0000

A substring w[i.j] in w is called a repetition of period p if w[k] = w[k + p] for any i ≤ k ≤ j - p. Especially, a maximal repetition, which cannot be extended neither to left nor to right, is called a run. The ratio of the length of the run to its period, i.e. [Formula: see text], is called an exponent. The sum of exponents of runs in a string is of interest. The maximal value of the sum is still unknown, and the current upper bound is 2.9n given by Crochemore and Ilie, where n is the length of a string. In this paper we show a closed formula which exactly expresses the average value of it for any n and any alphabet size, and the limit of this value per unit length as n approaches infinity. For binary strings, the limit value is approximately 1.13103. We also show the average number of squares in a string of length n and its limit value.

2009-01-Theor-Comput-Sci

Thu, 01 Jan 2009 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2008-01-PSC

Mon, 01 Sep 2008 00:00:00 +0000

2008-01-PSC-2

Mon, 01 Sep 2008 00:00:00 +0000

2008-01-RoboCup

Tue, 01 Jul 2008 00:00:00 +0000

This paper describes an interactive experimental environment for autonomous soccer robots, which is a soccer field augmented by utilizing camera input and projector output. This environment, in a sense, plays an intermediate role between simulated environments and…

2008-07-efs

Tue, 01 Jul 2008 00:00:00 +0000

2008-03-paper-070

Sat, 01 Mar 2008 00:00:00 +0000

2008-03-paper-071

Sat, 01 Mar 2008 00:00:00 +0000

2008-03-paper-072

Sat, 01 Mar 2008 00:00:00 +0000

2008-01-SOFSEM

Tue, 01 Jan 2008 00:00:00 +0000

This paper studies two problems on compressed strings described in terms of straight line programs (SLPs). One is to compute the length of the longest common substring of two given SLP-compressed strings, and the other is to compute all palindromes of a given…

2008-01-Structure-Based-Compression-of-Complex-M

Tue, 01 Jan 2008 00:00:00 +0000

In this paper we study the problem of deciding whether a given compressed string contains a square. A string x is called a square if x = zz and z = u^k implies k = 1 and u = z. A string w is said to be square-free if no substrings of w are squares. Many efficient algorithms to test if a given string is square-free, have been developed so far. However, very little is known for testing square-freeness of a given compressed string. In this paper, we give an O(max(n^2; n log^2 N))-time O(n^2)-space solution to test square-freeness of a given compressed string, where n and N are the size of a given compressed string and the corresponding decompressed string, respectively. Our input strings are compressed by balanced straight line program (BSLP). We remark that BSLP has exponential compression, that is, N = O(2^n). Hence no decompress-then-test approaches can be better than our method in the worst case.

SCIS2008

Tue, 01 Jan 2008 00:00:00 +0000

2007-01-Discovery-Science

Mon, 01 Oct 2007 00:00:00 +0000

In this paper, we propose a new concept, thinning-out, for reducing the number of trials in skill discovery. Thinning-out means to skip over such trials that are unlikely to improve discovering results, in the same way as “pruning” in a search tree. We…

JSAI-SIG-2007

Tue, 01 May 2007 00:00:00 +0000

COMP-2007-04

Fri, 20 Apr 2007 00:00:00 +0000

2006-01-IAS

Wed, 01 Mar 2006 00:00:00 +0000

2006-01-IAS-2

Wed, 01 Mar 2006 00:00:00 +0000

2006-03-paper-079

Wed, 01 Mar 2006 00:00:00 +0000

2006-01-RoboCup

Sun, 01 Jan 2006 00:00:00 +0000

This paper describes an autonomous learning method used with real robots in order to acquire ball trapping skills in the four-legged robot league. These skills involve stopping and controlling an oncoming ball and are essential to passing a ball to each other. We…

2005-09-paper-080

Tue, 20 Sep 2005 00:00:00 +0000

2005-01-FCT

Mon, 01 Aug 2005 00:00:00 +0000

Sequence comparison is a fundamental task in pattern matching. Its applications include file comparison, spelling correction, information retrieval, and computing (dis)similarities between biological sequences. A common scheme for sequence…

2005-01-WEA

Sun, 01 May 2005 00:00:00 +0000

The task of approximate string matching is to find all locations at which a pattern string p of length m matches a substring of a text string t of length n with at most k differences. It is common to use Levenshtein distance [5], which allows the differences to be…

2005-05-lua

Sun, 01 May 2005 00:00:00 +0000

2005-01-Discret-Appl-Math

Sat, 01 Jan 2005 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2005-01-Int-J-Found-Comput-Sci

Sat, 01 Jan 2005 00:00:00 +0000

We study the fully compressed pattern matching problem (FCPM problem): Given [Formula: see text] and [Formula: see text] which are descriptions of text T and pattern P respectively, find the occurrences of P in Twithout decompressing[Formula: see text]or[Formula: see text]. This problem is rather challenging since patterns are also given in a compressed form. In this paper we present an FCPM algorithm for simple collage systems. Collage systems are a general framework representing various kinds of dictionary-based compressions in a uniform way, and simple collage systems are a subclass that includes LZW and LZ78 compressions. Collage systems are of the form [Formula: see text], where [Formula: see text] is a dictionary and [Formula: see text] is a sequence of variables from [Formula: see text]. Our FCPM algorithm performs in [Formula: see text] time, where [Formula: see text] and [Formula: see text]. This is faster than the previous best result of O(m 2 n 2 ) time.

2005-01-SOFSEM

Sat, 01 Jan 2005 00:00:00 +0000

The approximate string matching problem is to find all locations at which a query p of length m matches a substring of a text t of length n with at most k differences (insertions, deletions, substitutions). The fastest solutions in practice for this problem are the…

2005-01-Theor-Comput-Sci

Sat, 01 Jan 2005 00:00:00 +0000

We consider a deterministic finite automaton which accepts all subsequences of a set of texts, called subsequence automaton. We show an online algorithm for constructing a subsequence automaton for a set of texts. It runs in O(|/spl Sigma/|(m+k)+N) time using O(|/spl Sigma/|m) space, where |/spl Sigma/| is the size of alphabet, m is the size of the resulting subsequence automaton, k is the number of texts, and N is the total length of texts. It can be used to preprocess a given set S of texts in such a way that for any query /spl omega/ /spl isin/ /spl Sigma/*, returns in O(|/spl omega/|) time the number of texts in S which contain /spl omega/ as a subsequence. We also show an upper bound of the size of automaton compared to the minimum automaton.

2004-01-Developments-in-Language-Theory

Wed, 01 Dec 2004 00:00:00 +0000

There is a close relationship between formal language theory and data compression. Since 1990’s various types of grammar-based text compression algorithms have been introduced. Given an input string, a grammar-based text compression algorithm constructs a…

2004-01-AIRS

Fri, 01 Oct 2004 00:00:00 +0000

There exist practical bit-parallel algorithms for several types of pair-wise string processing, such as longest common subsequence computation or approximate string matching. The bit-parallel algorithms typically use a size-σ table of match bit-vectors, where…

2004-01-ALT

Fri, 01 Oct 2004 00:00:00 +0000

Finding a good pattern which discriminates one set of strings from the other set is a critical task in knowledge discovery. In this paper, we review a series of our works concerning with the string pattern discovery. It includes theoretical analyses of learnabilities…

2004-01-Discovery-Science

Fri, 01 Oct 2004 00:00:00 +0000

We consider the problem of discovering the optimal pair of substring patterns with bounded distance α, from a given set S of strings. We study two kinds of pattern classes, one is in form…

2004-01-WABI

Wed, 01 Sep 2004 00:00:00 +0000

We consider the problem of finding the optimal pair of string patterns for discriminating between two sets of strings, i.e. finding the pair of patterns that is best with respect to some appropriate scoring function that gives higher scores to pattern pairs which…

2004-01-IEEE-ACM-Trans-Comput-Biol-Bioinform

Thu, 01 Jan 2004 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2004-01-J-Bioinform-Comput-Biol

Thu, 01 Jan 2004 00:00:00 +0000

We present an efficient algorithm for detecting putative regulatory elements in the upstream DNA sequences of genes, using gene expression information obtained from microarray experiments. Based on a generalized suffix tree, our algorithm looks for motif patterns whose appearance in the upstream region is most correlated with the expression levels of the genes. We are able to find the optimal pattern, in time linear in the total length of the upstream sequences. We implement and apply our algorithm to publicly available microarray gene expression data, and show that our method is able to discover biologically significant motifs, including various motifs which have been reported previously using the same data set. We further discuss applications for which the efficiency of the method is essential, as well as possible extensions to our algorithm.

2004-01-J-Discrete-Algorithms

Thu, 01 Jan 2004 00:00:00 +0000

2004-01-Theor-Comput-Sci

Thu, 01 Jan 2004 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2003-01-SPIRE

Wed, 01 Oct 2003 00:00:00 +0000

Given a text, grammar-based compression is to construct a grammar that generates the text. There are many kinds of text compression techniques of this type. Each compression scheme is categorized as being either off-line or on-line, according to how a text is…

2003-10-paper-084

Wed, 01 Oct 2003 00:00:00 +0000

2003-01-MFCS

Fri, 01 Aug 2003 00:00:00 +0000

We show the tight upperbound of the length of the minimum solution of a word equation L=R in one variable, in terms of the differences between the positions of corresponding variable occurrences in L and R. By introducing the notion of difference, the proof is…

2003-01-MFCS-2

Fri, 01 Aug 2003 00:00:00 +0000

This paper introduces a new problem of inferring strings from graphs, and inferring strings from arrays. Given a graph G or an array A, we infer a string that suits the graph, or the array, under some condition. Firstly, we solve the problem of finding a string w…

2003-01-Discovery-Science

Wed, 01 Jan 2003 00:00:00 +0000

The classificatory power of a pattern is measured by how well it separates two given sets of strings. This paper gives practical algorithms to find the fixed/variable-length-don’t-care pattern (FVLDC pattern) and approximate FVLDC pattern which are most…

2003-01-Nord-J-Comput

Wed, 01 Jan 2003 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2003-01-Theor-Comput-Sci

Wed, 01 Jan 2003 00:00:00 +0000

We study the problem of learning nearly $(s,\epsilon)$-sparse unitaries, meaning that the Pauli spectrum is concentrated on at most $s$ components with at most $\epsilon$ residual mass in Pauli $\ell_1$-norm. This class generalizes well-studied families, including sparse unitaries, quantum $k$-juntas, $2^k$-Pauli dimensional channels, and compositions of depth $O(\log\log n)$ circuits with near-Clifford circuits. Given query access to an unknown nearly sparse unitary $U$, our goal is to efficiently (both in time and query complexity) construct a quantum channel that is close in diamond distance to $U$. We design a learning algorithm achieving this guarantee using $\tilde{O}(s^6/\epsilon^4)$ forward queries to $U$, and running time polynomial in relevant parameters. A key contribution is an efficient quantum algorithm that, given query access to an arbitrary unknown unitary $U$, estimates all Pauli coefficients (up to a shared global phase) whose magnitude exceeds a given threshold $\theta$, extending existing sparse recovery techniques to general unitaries. We also study the broader class of unitaries with bounded Pauli $\ell_1$-norm. For that class, we prove an exponential query lower bound $\Omega(2^{n/2})$. We introduce a more relaxed accuracy metric which is the diamond distance restricted to a set of input states. Then, we show that, under this metric, unitaries with Pauli $\ell_1$-norm uniformly bounded by $L_1$ are learnable with $\tilde{O}(L_1^8/\epsilon^{16})$.

2003-01-Theor-Comput-Sci-2

Wed, 01 Jan 2003 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

2003-01-Theor-Comput-Sci-3

Wed, 01 Jan 2003 00:00:00 +0000

We introduce our research on compressed pattern matching technology that combines data compression and pattern matching. To show the results of this work, we explain the collage system proposed by Kida et al. in 2003 that is a unifying framework for compressed pattern matching, and we explain the Repair-VF method proposed by Yoshida and Kida in 2013 and the MR-Repair method proposed by Furuya et al. in 2019 as grammar compressions suitable for compressed pattern matching.

2002-01-Discovery-Science

Fri, 01 Nov 2002 00:00:00 +0000

A variable-length-don’t-care pattern (VLDC pattern) is an element of set Π = (∑∪{⋆}), where ∑ is an alphabet and ⋆ is a wildcard matching any string in ∑. Given two sets of strings, we consider the problem of finding…

2002-01-CPM

Mon, 01 Jul 2002 00:00:00 +0000

For a string w over an alphabet Σ, we consider a composite data structure called the all-suffixes directed acyclic word graph (ASDAWG). ASDAWG(w) has |w| + 1 initial nodes, and the dag induced by all reachable nodes from the k-th initial node conforms with…

2002-01-Progress-in-Discovery-Science

Tue, 01 Jan 2002 00:00:00 +0000

Finding a pattern which separates two sets is a critical task in discovery. Given two sets of strings, consider the problem to find a subsequence that is common to one set but never appears in the other set. The problem is known to be NP-complete. Episode pattern is…

2002-08-MFCS

Tue, 01 Jan 2002 00:00:00 +0000

The minimum all-suffixes directed acyclic word graph (MASDAWG) of a string w has |w| + 1 initial nodes, where the dag induced by all reachable nodes from the k-th initial node conforms with the DAWG of the k-th suffix of w. A new space-economical algorithm for the…

2002-09-SPIRE

Tue, 01 Jan 2002 00:00:00 +0000

Techniques in processing text files “as is” are presented, in which given text files are processed without modification. The compressed pattern matching problem, first defined by Amir and Benson (1992), is a good example of the “as-is”…

2001-01-ISAAC

Sat, 01 Dec 2001 00:00:00 +0000

A fragmentary pattern is a multiset of non-empty strings, and it matches a string w if all the strings in it occur within w without any overlaps. We study some fundamental issues on computational complexity related to the matching of fragmentary patterns. We show…

2001-01-Discovery-Science

Thu, 01 Nov 2001 00:00:00 +0000

The class of pattern languages was introduced by Angluin (1980), and a lot of studies have been undertaken on it from the theoretical viewpoint of learnabilities. However, there have been few practical studies except for the one by Shinohara (1982), in which patterns…

2001-01-Discovery-Science-2

Thu, 01 Nov 2001 00:00:00 +0000

Episode pattern is a generalized concept of subsequence pattern where the length of substring containing the subsequence is bounded. Given two sets of strings, consider an optimization problem to find a best episode pattern that is common to one set but not common in…

2001-01-SPIRE

Thu, 01 Nov 2001 00:00:00 +0000

2001-01-SPIRE-2

Thu, 01 Nov 2001 00:00:00 +0000

2001-01-PSC

Sat, 01 Sep 2001 00:00:00 +0000

DCC2001

Wed, 28 Mar 2001 00:00:00 +0000

DCC2001-Kida

Tue, 27 Mar 2001 00:00:00 +0000

A fundamental problem on strings in the realm of approximate string matching is pattern matching with mismatches: Given a text t, a pattern p, and a number k, determine whether some substring of t has Hamming distance at most k to p; such a substring is called a k-match. As real-world texts often come in compressed form, we study the case of searching for a small pattern p in a text t that is compressed by a straight-line program. This grammar compression is popular in the string community, since it is mathematically elegant and unifies many practically relevant compression schemes such as the Lempel-Ziv family, dictionary methods, and others. We denote by m the length of p and by n the compressed size of t. While exact pattern matching, that is, the case k = 0, is known to be solvable in near-linear time O (n + m) [Jez TALG'15], despite considerable interest in the string community, the fastest known algorithm for pattern matching with mismatches runs in time [MATH HERE] [Gawrychowski, Straszak ISAAC'13], which is far from linear even for very small k. In this paper, we obtain an algorithm for pattern matching with mismatches running in time O((n + m) poly(k)). This is near-linear in the input size for any constant (or slightly superconstant) k. We obtain analogous running time for counting and enumerating all k-matches. Our algorithm is based on a new structural insight for approximate pattern matching, essentially showing that either the number of k-matches is very small or both text and pattern must be almost periodic. While intuitive and simple for exact matches, such a characterization is surprising when allowing k mismatches.

2001-07-CPM

Mon, 01 Jan 2001 00:00:00 +0000

Compressed pattern matching is one of the most active top- ics in string matching. The goal is to find all occurrences of a pattern in a compressed text without decompression. Various algorithms have been proposed depending on underlying compression methods in the…

SPIRE2000-Matsumoto

Thu, 28 Sep 2000 00:00:00 +0000

SPIRE2000-Hirao

Wed, 27 Sep 2000 00:00:00 +0000

Internal Pattern Matching (IPM) queries on a text $T$, given two fragments $X$ and $Y$ of $T$ such that $|Y|<2|X|$, ask to compute all exact occurrences of $X$ within $Y$. IPM queries have been introduced by Kociumaka, Radoszewski, Rytter, and Wale'n [SODA'15&SICOMP'24], who showed that they can be answered in $O(1)$ time using a data structure of size $O(n)$ and used this result to answer various queries about fragments of $T$. In this work, we study IPM queries on compressed and dynamic strings. Our result is an $O(\log n)$-time query algorithm applicable to any balanced recompression-based run-length straight-line program (RLSLP). In particular, one can use it on top of the RLSLP of Kociumaka, Navarro, and Prezza [IEEE TIT'23], whose size $O\big(\delta \log \frac{n\log \sigma}{\delta \log n}\big)$ is optimal (among all text representations) as a function of the text length $n$, the alphabet size $\sigma$, and the substring complexity $\delta$. Our procedure does not rely on any preprocessing of the underlying RLSLP, which makes it readily applicable on top of the dynamic strings data structure of Gawrychowski, Karczmarz, Kociumaka, {\L}\k{a}cki and Sankowski [SODA'18], which supports fully persistent updates in logarithmic time with high probability.

SPIRE2000-Hoshino

Wed, 27 Sep 2000 00:00:00 +0000

2000-07-la-summer-bm

Tue, 18 Jul 2000 00:00:00 +0000

CPM2000

Thu, 01 Jun 2000 00:00:00 +0000

We apply the Boyer-Moore technique to compressed pattern matching for text string described in terms of collage system, which is a formal framework that captures various dictionary-based compression methods. For a subclass of collage systems that contain no…

CIAC2000

Wed, 01 Mar 2000 00:00:00 +0000

Byte pair encoding (BPE) is a simple universal text compression scheme. Decompression is very fast and requires small work space. Moreover, it is easy to decompress an arbitrary part of the orig- inal text. However, it has not been so popular since the compression is…

2000-01-New-Gener-Comput

Sat, 01 Jan 2000 00:00:00 +0000

An elementary formal system (EFS) is a logic program consisting of definite clauses whose arguments have patterns instead of first-order terms. We investig

1999-01-SPIRE-CRIWG

Wed, 01 Sep 1999 00:00:00 +0000

1999-09-paper-089

Wed, 01 Sep 1999 00:00:00 +0000

1999-09-paper-090

Wed, 01 Sep 1999 00:00:00 +0000

CPM99-Shibata

Fri, 23 Jul 1999 00:00:00 +0000

In this paper we focus on the problem of compressed pattern matching for the text compression using antidictionaries, which is a new compression scheme proposed recently by Crochemore et al. (1998). We show an algorithm which preprocesses a pattern of length m and an…

CPM99-Kida

Thu, 22 Jul 1999 00:00:00 +0000

This paper considers the Shift-And approach to the problem of pattern matching in LZW compressed text, and gives a new algorithm that solves it. The algorithm is indeed fast when a pattern length is at most 32, or the word length. After an O(m + |∑|) time and…

1999-03-paper-091

Mon, 01 Mar 1999 00:00:00 +0000

1999-01-Discovery-Science

Fri, 01 Jan 1999 00:00:00 +0000

1998-10-lzw-compressed-text-matching

Thu, 01 Oct 1998 00:00:00 +0000

JSPS1993

Thu, 01 Oct 1998 00:00:00 +0000

DCC98

Wed, 01 Apr 1998 00:00:00 +0000

1998-01-Inf-Process-Lett

Thu, 01 Jan 1998 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

CPM97

Tue, 01 Jul 1997 00:00:00 +0000

We show an efficient pattern-matching algorithm for strings that are succinctly described in terms of straight-line programs, in which the constants are symbols and the only operation is the concatenation. In this paper, both text T and pattern P are given by…

EuroCOLT97

Tue, 18 Mar 1997 00:00:00 +0000

A pattern is a finite string of constant and variable symbols. For k≥1, we denote by kμΠ the set of all patterns in which each variable symbol occurs at most k times. In particular, we abbreviate μΠ for k=1. The language L(π) of a…

1997-01-Nord-J-Comput

Wed, 01 Jan 1997 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

SWAT96

Thu, 04 Jul 1996 00:00:00 +0000

Ordered binary decision diagrams (OBDDs, for short) represent Boolean functions as directed acyclic graphs. The minimum consistent OBDD problem is, given an incomplete truth table of a function, to find the smallest OBDD that is consistent with the truth table with…

CPM95

Fri, 07 Jul 1995 00:00:00 +0000

We consider strings which are succinctly described. The description is in terms of straight-line programs in which the constants are symbols and the only operation is the concatenation. Such descriptions correspond to the systems of recurrences or to context-free…

1995-01-ISMB

Sat, 01 Jul 1995 00:00:00 +0000

1995-01-Electron-Colloquium-Comput-Complex

Sun, 01 Jan 1995 00:00:00 +0000

Homepage of the Electronic Colloquium on Computational Complexity located at the Weizmann Institute of Science, Israel

1995-01-Machine-Intelligence-15

Sun, 01 Jan 1995 00:00:00 +0000

1995-01-Theor-Comput-Sci

Sun, 01 Jan 1995 00:00:00 +0000

Abstract could not be automatically retrieved from the linked source. Please add the official abstract manually if available.

1994-01-AII-ALT

Sat, 01 Oct 1994 00:00:00 +0000

We propose a notion of the refutably PAC learning, which formalizes the refutability of hypothesis spaces in the PAC learning model. Intuitively, the refutably PAC learning for a concept class F requires that the learning algorithm should refute F with high…

1994-01-ECML

Fri, 01 Apr 1994 00:00:00 +0000

In the PAC-learning model, the Vapnik-Chervonenkis (VC) dimension plays the key role to estimate the polynomial-sample learnability of a class of binary functions. For a class of {0,…, m}-valued functions, the notion has been generalized in various ways. This paper…

1994-01-HICSS-5

Sat, 01 Jan 1994 00:00:00 +0000

1993-07-bonsai

Sun, 11 Jul 1993 00:00:00 +0000

1993-01-ALT

Fri, 01 Jan 1993 00:00:00 +0000

The Vapnik-Chervonenkis (VC) dimension is known to be the crucial measure of the polynomial-sample learnability in the PAC-learning model. This paper investigates the complexity of computing VC-dimension of a concept class over a finite learning domain. We consider a…

1993-01-New-Gener-Comput

Fri, 01 Jan 1993 00:00:00 +0000

This paper describes a machine learning system that discovered a “negative motif”, in transmembrane domain identification from amino acid seque

1992-12-genome-info-bonsai

Mon, 14 Dec 1992 00:00:00 +0000

1992-12-genome-info-dt

Mon, 14 Dec 1992 00:00:00 +0000

1991-07-pac-mat

Thu, 11 Jul 1991 00:00:00 +0000

1991-07-efs

Mon, 01 Jul 1991 00:00:00 +0000

1991-02-paper-116

Thu, 21 Feb 1991 00:00:00 +0000

1991-01-ALT

Tue, 01 Jan 1991 00:00:00 +0000

1991-01-New-Gener-Comput

Tue, 01 Jan 1991 00:00:00 +0000

This paper considers computational learning from the view-point of teaching. We introduce a notion of teachability with which we establish a relationship b

1991-01-Nonmonotonic-and-Inductive-Logic

Tue, 01 Jan 1991 00:00:00 +0000

Elementary formal system (EFS for short) is a kind of logic program directly dealing with character strings. In 1989, we proposed the class of variable-bounded EFS’s as a unifying framework for language learning. Responding to the proposal, several works have…

1990-07-jsai-alt

Mon, 23 Jul 1990 00:00:00 +0000

Mon, 01 Jan 0001 00:00:00 +0000

篠原・吉仲研究室のウェブサーバ再構築プロジェクト

環境構築の仕方

Windows 11

PowerShell で hugo のインストール
```
winget install Hugo.Hugo.Extended
```
ターミナルを開き直して，hugo versionと打ってバージョン番号(v0.160.1 など)が表示されればOK.

開発の仕方

このレポジトリのルートディレクトリで
```
hugo server -D
```
を実行し，そこに出力されている通りlocalhost:1313 にブラウザでアクセスすればよい．

Ayumi Shinohara

Mon, 01 Jan 0001 00:00:00 +0000

自己紹介

ここに挨拶や、研究に対する想いを自由に書いてください。 Markdown形式なので、太字やリンクも使えます。

Hidetaka Fujimoto

Mon, 01 Jan 0001 00:00:00 +0000

群馬県桐生市出身．誇り高きオパビニアの子孫．

Hikaru Konarita

Mon, 01 Jan 0001 00:00:00 +0000

所属サークル

東北大学軽音学部アステロイズ

Junya Saito

Mon, 01 Jan 0001 00:00:00 +0000

ここに紹介文を書く

Kaito Osawa

Mon, 01 Jan 0001 00:00:00 +0000

所属サークル

東北大学マイコンプロシージャ
https://micomprocedure.com/

Keigo Shimomura

Mon, 01 Jan 0001 00:00:00 +0000

出身地は新潟県

Nanako Omiya

Mon, 01 Jan 0001 00:00:00 +0000

所属サークル

学友会囲碁部

Naomi Ogasawara

Mon, 01 Jan 0001 00:00:00 +0000

ここに紹介文を書く

Nozomi Hagita

Mon, 01 Jan 0001 00:00:00 +0000

兵庫県神戸市出身です。

Rikuki Okada

Mon, 01 Jan 0001 00:00:00 +0000

大阪府出身です。バイクに乗るのが好きです。

Rui Oguchi

Mon, 01 Jan 0001 00:00:00 +0000

長野県安曇野市出身。北アルプスを望む自然豊かな環境で育ちました。

趣味

温泉・銭湯めぐり。サウナも一興。

所属サークル

旅行研究会

Ryo Yoshinaka

Mon, 01 Jan 0001 00:00:00 +0000

ここに紹介文を書く

Sebastian Danckwardt

Mon, 01 Jan 0001 00:00:00 +0000

ここに紹介文を書く

Shingo Katahira

Mon, 01 Jan 0001 00:00:00 +0000

秋田県秋田市出身．岩手大学理工学部システム創成工学科知能・メディア情報コース (現：知能情報コース/クリエイティブ情報コース) 卒．

Shiryu Sasaki

Mon, 01 Jan 0001 00:00:00 +0000

埼玉県新座市出身．

Souta Kobayashi

Mon, 01 Jan 0001 00:00:00 +0000

所属サークル

競技プログラミングサークル puzzleknot

Steven Liu

Mon, 01 Jan 0001 00:00:00 +0000

ここに紹介文を書く

Takahito Ono

Mon, 01 Jan 0001 00:00:00 +0000

M1 小野隆仁です。研究頑張ります！

Takehiro Ishibashi

Mon, 01 Jan 0001 00:00:00 +0000

兵庫県神戸市出身。

Tatsuki Yokota

Mon, 01 Jan 0001 00:00:00 +0000

千葉県民。

Towa Fujimaru

Mon, 01 Jan 0001 00:00:00 +0000

青森県出身．パズルと麻雀が大好物です．

Yunosuke Toyofuku

Mon, 01 Jan 0001 00:00:00 +0000

趣味：ゲーム

活動地図

Mon, 01 Jan 0001 00:00:00 +0000

これまで論文発表を行った国内外の場所や，卒業生の活躍の場を可視化しています．世界征服を企んでいます．

連絡先

Mon, 01 Jan 0001 00:00:00 +0000

住所

〒980-8579
宮城県仙台市青葉区荒巻字青葉 6-6-05
東北大学大学院情報科学研究科
システム情報科学専攻
（学内便記号番号：青A13-05）

所在地

工学研究科電子情報システム・応物系 1号館 (D10)

篠原・吉仲研究室 on

文字列処理

機械学習の理論と応用

ゲーム情報学

花見 2026

卒業式

CGP2026-Ishibashi

2026-03-WALCOM

SOFSEM2026

CJCDCGGG2025

CIAC2025

CPM2025

卒業式

CGP2025-BusOut

LA2024Winter

冬のLAシンポジウム in 京都 2024

SOFSEM2025

Acta-Informatica-2024

2024-01-ICALP

TCS2024-Diptarama

TCS2024-Kawahara

CPM2024

SOFSEM2024

2024-08-SEAA

STRセミナー2024 in札幌

オープンキャンパス 2024

ソフトボール大会決勝 2024

芋煮2024

花見 2024

電気・情報系・通研駅伝大会 2024

Theoretical Computer Science 2023

電気・情報系・通研駅伝大会 2023

芋煮 2023

SPIRE2023

STRセミナー 2023

ICGI2023

ICGI2023-Kanazawa

ICGI 2023

2022年度 電気関係学会東北支部連合大会 情報処理学会東北支部奨励賞 受賞

2023-01-WALCOM-2

WALCOM2023-Kumagai

JPHACKS 2022 Award Day にてJPHACKS Innovator認定と合同会社MIRAISE賞を受賞

2023-02-la-sympo-winter

LA sympo in Winter

2022-11-game-prog

SPIRE2022

電気・情報系・通研駅伝大会 2022

技育展2022 インフラ/セキュリティ部門 最優秀賞受賞

Theoretical Computer Science 2022

STRセミナー2022 熊谷滉士郎 若手奨励賞 受賞

STRセミナー2022

CPM2022

2022-02-la-sympo-winter-dava

2022-02-la-sympo-winter-ichikawa

2022-02-la-sympo-winter-ishizuka

ICGI2021-Kambe

ICGI2023-Kaito

ICGI2023-kanazawa

工学部長賞受賞

2021-01-WALCOM

2020-12-comp

SPIRE2020

2020-01-ETFA

篠原教授が東北大学総長教育賞を受賞

CPM2020-Funakoshi

CPM2020-Köppl

CPM2020-Nakashima

SEA2020

情報処理学会東北支部学生奨励賞受賞

TCS2020-Narisada-gap

TCS2020-Narisada-walk

LAシンポジウム冬 2019

DCC2020

総長賞受賞

2020-02-la-winter-dava

2020-02-la-winter-nakashima

2020-02-la-winter-natsumi

SOFSEM 2020

SOFSEM2020

篠原教授が東北大学全学教育貢献賞を受賞

2022年度電気関係学会東北支部連合大会情報処理学会東北支部奨励賞受賞

技育展2022 インフラ/セキュリティ部門最優秀賞受賞

STRセミナー2022 熊谷滉士郎若手奨励賞受賞

情報処理学会東北支部第13回野口研究奨励賞を受賞

JPHACKS2017 審査員特別賞＆イノベータ認定受賞

GPW杯デジタルカーリング大会準優勝

2016年度東北大学工学部長賞受賞