Kenta Murata

• Software Enginner
• CRuby Committer

Identifications

• mrkn AT mrkn.jp
• mrkn's diary (My Japanese Blog)
• ドレッシングな日々 (My Old Japanese Blog)
• Anything (My English Blog)
• @KentaMurata
• mrkn
• mrkn720
• mrkn22
• mrkn

Skills

• Program languages
  • Ruby
  • C
  • C++
  • Python
  • Julia
  • Swift
  • Objective-C
  • JavaScript
  • CoffeeScript
  • Assembly languages
  • Bourne Shell script
  • GNU R
  • Vim script
  • Emacs Lisp
• Frameworks, Middlewares, and Libraries
  • Ruby on Rails
  • Sinatra
  • Rack
  • Boost
• Database management systems
  • Redis
  • PostgreSQL
  • SQLite
  • MySQL
  • Berkley DB
• TDD and BDD
  • RSpec
  • Cucumber
  • test-unit
  • CUnit
  • CppUnit
• Markup languages
  • HTML
  • XML
  • Haml
  • Markdown
  • YAML
  • LaTeX
  • PHP
• Operating Systems
  • Mac OS X
  • Linux
  • Windows
• Other development systems
  • Vim
  • Emacs
  • Git
  • Subversion
  • CVS
  • Visual Studio
• Sicence
  • Complex systems' dynamics
  • Complex networks
  • Multi-agent systems
  • Machine Learning
  • Reinforcement Learning
  • Schedule optimization

Professional Experiences

Speee Inc.: Full-time OSS developer, Ruby committer, Technical advisor for R&D department

April 2019 – Present

Speee Inc.: Full-time Ruby committer

February 2017 – March 2019

Recruit Inc.: Software Engineer

April 2016 – January 2017

COOKPAD Inc.: Software Engineer

December 2011 – March 2016

• Supporting development environment and infrastructures.
• Development of CRuby.

Genetic Lab Co., Ltd.: Software Engineer

August 2009 – November 2011

• Directing development of security policy for the company.
• Development of medical system for pathological diagnoses using Ruby on Rails, PostgreSQL.
• Development of distributed PDF generation and printing system using Prawn and Resque.

Axis Co., Ltd.: Software Engineer

August 2009 – September 2009

• Refinement of legacy code using Ruby on Rails, PHP, and MySQL.

Technoface Co., Ltd.: Software Test Engineer

June 2009 – September 2009

• Integration testing of Japanese mobile applications.

Sapporo Mirai Professional Training College of Information Technology: Instructor

October 2004 – September 2009

• Instruct the following courses.
  • Windows 2003 Server system management.
  • Linux server management.
  • Apache and Squid configuration and management.
  • PHP programming.
  • The fundation of cryptographic algorithms.
  • The foundation of digital electronic circuts.
  • Programming with Win32 API.
  • Programming with Java for Japanese mobile platforms.
  • Introduction to security for companies.
  • Introduction to security for information systems.

Tomakomai National College of Technology: Instructor

October 2007 – September 2008

• Develop curriculum for computer science.
• Instruct the following courses.
  • The theory for programming languages and compilers.
  • Complex sytems and complex networks.
  • Introduction to the relationship between information theory and thermodynamics.
  • Introduction to Fractals.

Hokkaido Eisei Gakuin: Instructor

April 2005 – March 2009

• Instruct introduction course for information science and engineering.

Open Source Contributions

CRuby: Committer

February 2010 – Present

• Maintanance of bigdecimal library.
• Improvement CRuby performance, esp. algorithms for Bignum airthmetic.
• Bugfixs.

Momonga Project: Developer

July 2002 – June 2004

• Development of Momonga Linux (a Japanese Linux distribution).

Kondara Project: Developer

October 2000 – July 2002

• Development of Kondara MNU/Linux (a Japanese Linux distribution).

Others

Prawn

• Fixing table rendering.

Hiki

• Implementing plugin exporting/unexportin mechanism.

tDiary

• A bugfix.

Community Activities

Ruby Sapporo: Operation Team Member

2007 – 2011

• Hold the workshop called “The RSpec Book Reading Sapporo” (2010 – Present).
• Hold the regular workshop for Ruby.

Kosen Conference: Director

2010 – Present

• Manage the domain name.
• Manage reception email addresses for each conference.

RubyKaigi Executive Committee: KaigiFreaks

2008 – 2009

• On-line broadcasting (2008).
• Network infrastructure.
• The conference char (2009).
• Miscellaneous business.

Achievements

Japanese Books

2009

• 島田浩二, 設樂洋爾, 村田賢太, 前田智樹, 谷口文威. Ruby 逆引きレシピ. 翔泳社 (2009) [Support]

Refreed Japanese Papers

2009

• 村田賢太, 鈴木育男, 山本雅人, 古川正志. スケールフリーネットワークの生成方法およびベキ指数が結合振動子ネットワークの同期へ与える影響. 知能と情報 (日本知能情報ファジィ学会誌) Vol.21，No.2，pp.265–276 (2009).

2004

• 村田賢太, 吉井伸一郎, 渡辺美知子, 古川正志, 嘉数侑昇. On-line Profit Sharing による複数AGV の自律走行. 情報科学技術レターズ Vol.4, pp.125–127 (2004)

Non-refreed Japanese Papers

2003

• 村田賢太, 木下正博, 渡辺美知子, 古川正志. 熱力学に基づく群ロボットのマクロ制御—熱力学パラメータと群ロボットの行動—. 旭川工業高等専門学校研究報文 (40), pp.41–49 (2003) [CiNii]

Refereed International Talks

2012

• Kenta Murata, Shingo Morita. Chanko: How COOKPAD safely releases multiple feature prototypes - in production - for test segments of their 15 million engaged users. RailsConf 2012, Austin, TX, U.S. (26 April 2012) [LINK]

2011

• Kenta Murata. Float is Legacy. RubyConf 2011, New Orleans, U.S. (30 September 2011) [LINK]

2008

• Kenta Murata, Ikuo Suzuki, Masahito Yamamoto, Masashi Furukawa. Synchronization Effects on Clustering Coefficient Characteristics in Scale-free Networks. In Proceedings SCIS&ISIS2008, Nagoya University, Japan (21 September 2008)

2006

• Kenta Murata, Shinichiro Yoshii, Masashi Furukawa. Analysis of collective dynamics on the interaction structure with coupled oscillator network. In Proceedings of SCIS&ISIS2006, Tokyo Institute of Technology (September 2006)

2005

• Kenta Murata, Shinichiro Yoshii. Analyze and generalize the multi-human dynamics through the complex graphs. In Proceedings of IES2005, Hakodate Future University (November 2005).

2004

• Kenta Murata, Shinichiro Yoshii, Michiko Watanabe, Masashi Furukawa, Yukinori Kakazu. Autonomous Driving of Multiple AGVs by Use of On-line Profit Sharing. ICAM'04, pp.607–610, Asahikawa Grand Hotel, Asahikawa, Japan (October 2004).

Invited Japanese Talks

2013

• Kenta Murata. How to make easy and casual CI management in COOKPAD. Testing Casual Talks #1, :DeNA (24 July 2013) [LINK]

• 村田賢太. クックパッドのサービス開発を支える Ruby の技術. 第181回コンピュータ産業研究会. 東京, 日本 (26 March 2013)

2012

• Kenta Murata. Ruby technologies activating the development of COOKPAD. Ruby Business Seminar. Tokyo, Japan (10 December 2012) [LINK]

Refereed Japanese Talks

2012

• Kenta Murata. Distributed RSpec. Sapporo RubyKaigi 2012. Sapporo, Japan (16 September 2012) [LINK]

2011

• Kenta Murata. The world without the literal notation for floating-point numbers. Lightening Talks, RubyKaigi 2011, Tokyo Japan (18 July 2011) [LINK]

2010

• Kenta Murata. The future of the bigdecimal library and the number system of Ruby. RubyKaigi 2010, Tsukuba Japan (29 August 2010) [LINK]

2009

• Kenta Murata. The standard random number generator of Ruby and the proposal to improve it. RubyKaigi 2009, Tokyo Japan (17 July 2009) [LINK]

Non-refreed Japanese Talks

2013

• Kenta Murata. What a hard work to make the recipe sharing service available on Ruby 1.9.3. Oedo RubyKaigi 03. Tokyo, Japan (16 March 2013) [LINK]

2011

• 村田賢太. Ruby 1.9.3 の新機能と変更点. Ruby 勉強会@札幌-18, 札幌, 日本 (2 July. 2011)
• 村田賢太. 関数プログラミングの世界 (Welcome to the world of functional programming). オープンソースカンファレンス 2011 Hokkaido, 札幌, 日本 (11 June 2011)
• 村田賢太. Let’s Begin Behavior Driven Development using RSpec. 第58回 CLR/H 勉強会, 札幌, 日本 (21 May 2011)
• 村田賢太. Ruby をたのしくするために私が考えていること. Hokuriku.rb × 高専カンファレンス, 石川, 日本 (20 March 2011)
• 村田賢太. Ruby の懸案事項. Ruby 勉強会@札幌-16, 札幌, 日本 (20 February 2011)
• 村田賢太. 5分で分かる量子ビット. LOCAL Developer Day 2011 Winter, 定山渓, 日本 (10 February 2011)

2010

• Kenta Murata. Implementation of fast multiplication and division algorithms, and evaluating their performance (高速な乗除算の実現と性能評価). Sapporo RubyKaigi 03, Sapporo Japan (4 December 2010) [USTREAM]
• 村田賢太. コンピュータで数を扱う事について. 高専カンファレンス in 北海道2, 苫小牧, 日本 (29 May 2010)

2009

• 村田賢太. 校内勉強会のススメ (An encouragement to hold workshops in your school). Lightning Talks, 高専カンファレンス 2009秋 in 東京, 産業技術高等専門学校荒川キャンパス, 日本 (7 November 2009)

2008

• 村田賢太. 5分で分かる Measure. Lightening Talks, 札幌 Ruby 会議 01, 札幌, 日本 (25 October 2008)
• 村田賢太. Measure 単位付き数値ライブラリ. Ruby 勉強会@札幌-09, 札幌, 日本 (23 Aug. 2008)
• 村田賢太, 鈴木育男, 山本雅人, 古川正志. 複雑ネットワーク上の結合振動子における次数と同期の関係. 第80回知識ベース研究会 SIG-KBS-A703, pp.27–32, NTT武蔵野研究開発センター, 日本 (16 January 2008) [CiNii]

2007

• 村田賢太. Ruby 拡張モジュール入門. Ruby 勉強会@札幌-06, 札幌, 日本 (17 Nov. 2007)
• 村田賢太, 吉井伸一郎, 古川正志. 非均一ネットワーク結合力学系における同期状態の時間発展. 第147回知能と複雑系研究会 SIG-ICS 147, ルスツリゾート (16 March 2007) [CiNii]

2006

• 村田賢太, 吉井伸一郎. 異なる指向性をもつ集団組織の融合分離ダイナミクス. 第143回知能と複雑系研究会, pp.19–24, 国立情報学研究所学術総合センター (28 March 2006)
• 村田賢太, 森本浩之, 吉井伸一郎. インターネット・オークションにおける人間間相互作用についての考察. 2006年度精密工学会春季大会学術講演会, 東京理科大学 (March 2006) [J-GLOBAL]
• 村田賢太, 吉井伸一郎. 2次元 totalistic-cellular automata のダイナミクスと状態遷移グラフのネットワーク的観点に基づく関連性. 第18回自律分散システム・シンポジウム, 福井県国際交流会館 (January 2006) [CiNii]

2004

• 村田賢太, 渡辺美知子, 古川正志. 強化学習による複数 AGV の自律走行. 2004年度精密工学会春季大会学術講演会, 東京大学 (March 2004) [J-GLOBAL]

2003

• 村田賢太, 渡辺美知子, 古川正志. 熱力学に基づくマルチエージェントシステムの群制御. 2003年度精密工学会秋季大会学術講演会. 富山大学 (October 2003) [J-GLOBAL]
• 村田賢太, 渡辺美知子, 古川正志. 熱力学に基づくマルチエージェント群制御. 2003年度精密工学会北海道支部学術講演会, 室蘭工業大学 (September 2003)
• 村田賢太, 渡辺美知子, 古川正志. 熱力学に基づく群ロボットのマクロ制御—群ロボットの振舞いの制御—. 2003年度精密工学会春季大会学術講演会, 東京農工大学 (March 2003) [J-GLOBAL]

2002

• 村田賢太, 渡辺美知子, 古川正志. 熱力学に基づく群ロボットのマクロ制御—熱力学パラメータと群ロボットの行動—. 2002年度精密工学会北海道支部学術講演会, 札幌学院大学 (October 2002)

Educations

• Graduated from Hokkaido University in 2009 with a Ph.D in Synergetic Information Science.
• Graduated from Hokkaido University in 2006 with a Master of Information Science and Technology.