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MORIYA Sen

    Department of Informatics　Associate Professor
Last Updated :2024/04/25

Researcher Information

J-Global ID

Research Interests

  • Coding Theory   fault tolerance   distributed system   algorithms   

Research Areas

  • Informatics / Information theory

Academic & Professional Experience

  • 2022/04 - Today  Kindai UniversityFaculty of Informatics Department of InformaticsAssociate Professor
  • 2021/01 - Today  Kindai UniversityCyber Informatics Research Institute
  • 2002/04 - 2022/03  Kindai UniversityDepartment of Informatics, Faculty of Science and Engineering
  • 2000/04 - 2002/03  NTT Communication Science Laboratories

Education

  •        - 2000  Nara Institute of Science and Technology  Graduate School of Information Science
  •        - 1995  Osaka University  School of Science  Department of Mathematics

Association Memberships

  • 情報処理学会   電子情報通信学会   

Published Papers

  • MORIYA Sen; SASANO Hiroshi
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences The Institute of Electronics, Information and Communication Engineers E106.A (3) 375 - 381 0916-8508 2023/03 [Refereed]
     
    In this study, we consider techniques for searching high-rate convolutional code (CC) encoders using dual code encoders. A low-rate (R = 1/n) CC is a dual code to a high-rate (R = (n - 1)/n) CC. According to our past studies, if a CC encoder has a high performance, a dual code encoder to the CC also tends to have a good performance. However, it is not guaranteed to have the highest performance. We consider a method to obtain a high-rate CC encoder with a high performance using good dual code encoders, namely, high-performance low-rate CC encoders. We also present some CC encoders obtained by searches using our method.
  • AZUMA Ryoto; MORIYA Sen
    IEICE Transactions on Information and Systems (Japanese Edition) J103-D (1) 1 - 12 1881-0225 2020/01 [Refereed]
  • Sen Moriya; Kana Kikuchi; Hiroshi Sasano
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences Institute of Electronics, Information and Communication, Engineers, IEICE E100A (12) 2607 - 2614 1745-1337 2017/12 [Refereed]
     
    In this study, we consider techniques to search for highrate punctured convolutional code (PCC) encoders by rearranging row vectors of identical-encoder generator matrices. One well-known method to obtain a good PCC encoder is to perform an exhaustive search of all candidates. However, this approach is time-intensive. An exhaustive search with a rate RG = 1/2 original encoder requires a relatively short time, whereas that with an RG = 1/3 or lower original encoder takes significantly longer. The encoders with lower-rate original encoders are expected to create better PCC encoders. Thus, this paper proposes a method that uses exhaustive search results with rate RG = 1/2 original encoders, and rearranges row vectors of identical-encoder generator matrices to create PCCs with a lower rate original code. Further, we provide PCC encoders obtained by searches that utilize our method.
  • Sen Moriya; Kana Kikuchi; Hiroshi Sasano
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG E99A (12) 2162 - 2169 1745-1337 2016/12 [Refereed]
     
    In this study, we consider techniques to search for highrate punctured convolutional code (PCC) encoders using dual code encoders. A low-rate R = 1/n convolutional code (CC) has a dual code that is identical to a PCC with rate R = (n - 1)/n. This implies that a rate R = 1/n convolutional code encoder can assist in searches for high-rate PCC encoders. On the other hand, we can derive a rate R = 1/n CC encoder from good PCC encoders with rate R = (n = 1)/n using dual code encoders. This paper proposes a method to obtain improved high-rate PCC encoders, using exhaustive search results of PCC encoders with rate R = 1/3 original encoders, and dual code encoders. We also show some PCC encoders obtained by searches that utilized our method.
  • Hiroshi Sasano; Kana Kikuchi; Sen Moriya
    PROCEEDINGS OF 2016 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2016) IEEE 498 - 501 2016 [Refereed]
     
    There exists an identical high rate ordinary convolutional code with a punctured convolutional code. We show a method for obtaining good rate R = (n - 1) / n punctured convolutional codes through the identical codes with the best punctured convolutional codes of rate (n - 1) / n obtained by exhaustive searches for rate 1/2 original codes and puncturing matrices, and the method can find out punctured convolutional codes superior to the best code obtained by exhaustive searches for rate 1/3 original codes and puncturing matrices. For generating matrices of identical codes, we construct new identical codes with punctured convolutional codes by combining row vectors of each individual matrix. We present good punctured convolutional codes with rate R = (n - 1) / n,n = 6, ... , 13 by computer searches through those identical codes.
  • Sen Moriya; Kana Kikuchi; Hiroshi Sasano
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG E98A (7) 1579 - 1583 1745-1337 2015/07 [Refereed]
     
    This paper considers a method for constructing good highrate punctured convolutional codes through dual codes. A low-rate R = 1/n convolutional code has a dual code identical to a punctured convolutional code with rate R = (n - 1)/n. This implies that a low-rate R = 1/n convolutional code encoder can help the search of punctured convolutional code encoders. This paper provides the procedures that obtain all the useful dual code encoders to a given CC with rate R = 1/n easily, and the best PCC encoder with rate R = (n - 1)/n among the encoders we derive from all the obtained dual code encoders. This paper also shows an example of the PCC the procedures obtain from some CC.
  • Kana Kikuchi; Sen Moriya; Hiroshi Sasano
    2014 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA) IEEE 100 - 104 2014 [Refereed]
     
    Punctured convolutional codes are error-correcting codes that can be used to achieve reliable data transfer in digital communication systems. This paper considers a method to search good high-rate punctured convolutional code encoders using dual codes, which are often utilized to evaluate block codes. A low-rate R = 1/n convolutional code has a dual code identical to a punctured convolutional code with rate R = (n - 1)/n. This implies that a low-rate R = 1/n convolutional code can help the search of punctured convolutional code encoders. In simple terms, this means that the strategy involves searching all of many candidate dual code encoders. This paper shows it is not difficult to list all the useful dual code encoders from a given convolutional code with rate R = 1/n, and we give some examples of the best punctured convolutional code encoder with rate R = (n 1)/n obtained through dual code.
  • Sen Moriya; Hiroshi Sasano
    IEICE TRANSACTIONS ON FUNDAMENTALS OF ELECTRONICS COMMUNICATIONS AND COMPUTER SCIENCES IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG E96A (12) 2374 - 2381 0916-8508 2013/12 [Refereed]
     
    We consider two methods for constructing high rate punctured convolutional codes. First, we present the best high rate R = (n-1)/n punctured convolutional codes, for n = 5, 6, ..., 16, which are obtained by exhaustive searches. To obtain the best code, we use a regular convolutional code whose weight spectrum is equivalent to that of each punctured convolutional code. We search these equivalent codes for the best one. Next, we present a method that searches for good punctured convolutional codes by partial searches. This method searches the codes that are derived from rate 1/2 original codes obtained in the first method. By this method, we obtain some good punctured convolutional codes relatively faster than the case in which we search for the best codes.
  • A Study on Constructing High Rate Punctured Convolutional Codes by Using Dual Codes
    Kana Kikuchi; Hiroshi Sasano; Sen Moriya
    IEICE Transactions on Fundamentals (Japanese Edition) J96-A (10) 726 - 730 1881-0195 2013/10 [Refereed]
  • A Construction of high rate convolutional codes
    Hiroshi Sasano; Sen Moriya
    IEICE Transactions on Fundamentals (Japanese Edition) J96-A (7) 502 - 505 1881-0195 2013/07 [Refereed]
  • Hiroshi Sasano; Sen Moriya
    2012 INTERNATIONAL SYMPOSIUM ON INFORMATION THEORY AND ITS APPLICATIONS (ISITA 2012) IEEE 662 - 666 2012 [Refereed]
     
    We consider two methods that construct high rate punctured convolutional codes. First, we present best high rate R = (n - 1)/n punctured convolutional codes, for n = 5, 6, ... , 16, which are found by exhaustive searches. To obtain the best code, we use a regular convolutional code whose weight spectrum is equivalent to that of each punctured convolutional code. We search these regular equivalent codes for the best one. Next, we present a method that searches for good punctured convolutional codes by partial searches. This method searches the codes that are derived from R = 1/2 original codes obtained in the first method. By this method, we obtain some good punctured convolutional codes that have superior performance compared with that of the best codes.
  • Sen Moriya; Tadashi Araragi
    Electronics and Communications in Japan, Part III: Fundamental Electronic Science (English translation of Denshi Tsushin Gakkai Ronbunshi) 88 (12) 43 - 57 1042-0967 2005/12 [Refereed]
     
    This paper considers an Internet agent system in which a tremendous number of agents operate, frequently appearing and disappearing, and discusses the fault-tolerant algorithm. Application of the snapshot algorithm to the agent system is considered. The snapshot algorithm is used to view the whole situation (snapshot) of the distributed system. The snapshot algorithm of Chandy and Lamport [2] is considered as a representative snapshot algorithm, in terms of the high efficiency and the simplicity of the procedure. It is not practical, however, to apply their snapshot algorithm to the distributed agent system in which a tremendous number of agents operate. From such a viewpoint, this paper extends the idea of Chandy and Lamport's algorithm and proposes a subsnapshot algorithm, in which the snapshot is taken among the agents who are in the causal relation, through message exchange and agent creation. Then, an efficient rollback algorithm is proposed, which is based on the snapshots taken by the subsnapshot algorithm. In the general rollback algorithm utilizing the snapshot, all agents must roll back. In contrast, in the rollback algorithm proposed in this paper, it suffices that only some agents should roll back. © 2005 Wiley Periodicals, Inc.
  • Sen Moriya; Tadashi Araragi
    IEICE Transactions on Information and Systems (Japanese Edition) The Institute of Electronics, Information and Communication Engineers J86-D (5) 301 - 317 0915-1915 2003/05 [Refereed]
     
    本論文では,莫大な数のエージェント動作し,それらのエージェントが頻繁に生成,消滅するようなインターネットエージェントシステムの耐故障アルゴリズムを考察する.本論文では,エージェントシステムへスナップショットアルゴリズムを適用することを考える.スナップショットアルゴリズムとは,分散システム全体の状況(スナップショット)を求めるアルゴリズムである.特に,Chandyらのスナップショットアルゴリズム[2]は,効率の良さ,手続きの単純さから代表的なスナップショットアルゴリズムになっている.しかし,Chandyらのスナップショットアルゴリズムを莫大な数のエージェントが動作する分散エージェントシステムへ適用することは実用的ではない.そこで,本論文では,Chandyらのアルゴリズムのアイデアを拡張し,メッセージ交換やエージェント生成などを通じて因果関係をもつエージェント間でスナップショットをとるサブスナップショットアルゴリズムを提案する.更に,サブスナップショットアルゴリズムによってとられたスナップショットを利用した効率的なロールバックアルゴリズムを提案する.スナップショットを利用した一般的なロールバックアルゴリズムでは一部のエージェントのみがロールバックすればよい.
  • Dynamic Snapshot Algorithm and Partial Rollback Algorithm for Internet Agents
    Sen Moriya; Tadashi Araragi
    15th International Symposium on Distributed Computing 2001/10 [Refereed]
  • S Moriya; K Suda; M Inoue; T Masuzawa; H Fujiwara
    IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS IEICE-INST ELECTRONICS INFORMATION COMMUNICATIONS ENG E83D (8) 1611 - 1621 0916-8532 2000/08 [Refereed]
     
    We consider a wait-free linearizable implementation of shared objects on a distributed message-passing system. We assume that the system provides each process with a local cluck that runs: at the same speed as global time and that all message delays are in the range [d - u, d] where d and u. (0 < u less than or equal to d) are constants known to every process. We present four wait-free linearizable implementations of read/write registers on reliable and unreliable broadcast models. We also present two wait-free linearizable implementations of general objects on a reliable broadcast model. The efficacy of an implementation is measured by the worst-case response time for each operation of the implemented object. Response times of our wait-free implementations of read/write registers on a reliable broadcast model is better than a previously known implementation in which wait-freedom is not taken into account.
  • Sen Moriya; Michiko Inoue; Toshimitsu Masuzawa; Hideo Fujiwara
    IEICE Transactions on Information and Systems (Japanese Edition) The Institute of Electronics, Information and Communication Engineers J83-D (1) 99 - 109 0915-1915 2000/01 [Refereed]
     
    共有メモリマルチプロセッサシステム, 特に, システム内のすべてのプロセッサが大域パルスを共有するフェーズ内システムにおける故障耐性をもつ時計合せプロトコルを考察する.フェーズ内システムでは, 正常なプロセッサはパルス発生時に同期して動作を行う.フェーズ内システムにおいて, パルス発生時にプロセッサが動作しないような故障を居眠り故障と呼ぶ.居眠り故障の起こるフェーズ内システムにおいて, 同期時間と呼ばれるある特定パルス以上正常に動作し続けているすべてのプロセッサ同士の局所時計の時刻を一致させるプロトコルを無待機時計合せプロトコルと呼ぶ.これまで, フェーズ内システムにおける無待機時計合せプロトコルとして, 同期時間4n~2-3n-1のプロトコルが提案されていた(n:プロセッサ数).本論文では, 同期時間12nの無待機時計合せプロトコルを提案する.また, 無待機時計合せプロトコルの同期時間の下界がn-1であることを証明し, 本論文で提案するプロトコルが同期時間に関してオーダ的に最適であることを示す.
  • Wait-Free Linearizable Distributed Shared Memory
    S. Moriya; K. Suda; M. Inoue; T. Masuzawa; H. Fujiwara
    Proc. of the 11th IASTED International Conference on Parallel and Distributed Computing and Systems 335 - 342 1999/11 [Refereed]
  • Self-Stabilizing Wait-Free Clock Synchronization with Bounded Space
    Sen Moriya; Michiko Inoue; Toshimitsu Masuzawa; Hideo Fujiwara
    Proc. of the 2nd International Conference on Principles of Distributed Systems 129 - 143 1998/12 [Refereed]
  • M Inoue; S Moriya; T Masuzawa; H Fujiwara
    DISTRIBUTED ALGORITHMS, PROCEEDINGS SPRINGER-VERLAG BERLIN 1320 290 - 304 0302-9743 1997 [Refereed]
     
    We consider wait-free clock synchronization protocols on an in-phase shared-memory multi-processor system. A wait-free clock synchronization protocol guarantees that, for a fixed k, local clocks of processors which have been working consecutively for at least k pulses are synchronized. Such k is called synchronization time. The best previous result with regard to the synchronization time is O(n(2)), where n is the number of processors, In this paper, we present a wait-free synchronization protocol with synchronization time O(n), and also show that this synchronization time is asymptotically optimal.

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  • 耐故障分散アルゴリズムに関する研究

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