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Toshihide Ibaraki

Toshihide Ibaraki


  • Bachelor of Engineering, Kyoto University, Graduate School of Engineering, Kyoto University (Department of Electronics), Doctor of Engineering
  • Professor Emeritus, Kyoto University; Former Dean, Graduate School of Informatics, Kyoto University, Former Professor, Toyohashi University of Technology,Former Professor, Kwansei Gakuin University, Visiting Researcher, University of Illinois, etc.
  • Fellow of ACM, Institute of Electronics, Information and Communication Engineers, Japan Society of Applied Mathematics and 4 other academic societies
  • The Operations Research Society of Japan, the Scheduling Society, and two other honorary members of the Society
  • President, The Kyoto College of Graduate Studies for Informatics


I have been conducting research in fields such as "algorithm", "theory of computational complexity" and "optimization and its applications". In particular, I have been interested in how to solve various discrete optimization problems, and have developed algorithms for this purpose. Discrete optimization is an abstract term, but there are many problems in our daily lives, such as forming class schedules and work schedules, calculating the shortest path on a map (car navigation system), packing boxes so that there is as little space as possible in a small area (VLSI, building layout, loading onto trucks, etc.), creating train schedules, scheduling production at factories, and planning sports and games matches.

These are mathematically difficult problems, but recent advances in algorithms have made them more practical. However, it is difficult and impossible to develop advanced algorithms for each of the infinite individual problems. Therefore, we set up some standard problems and when we encounter a specific problem, we model it as one of the standard problems and then apply the algorithm of the standard problem to solve it. Linear and integer programming are well known as general-purpose algorithms that can be used for this purpose, and commercial packages are available. However, this is not enough, so in our research we have focused on selecting new standard problems and developing general algorithms for them. Some of the algorithms we have developed have already been incorporated into commercial software to help solve problems in various areas. We are also trying to solve specific problems by using them.

The basic theory of discrete optimization is being studied in the fields of "graph network theory", "integer programming", "meta-heuristics", "branch and bound method", "logical function", and "algorithm theory". Many of my research papers have described mathematical results in these fields, but I am now interested in application research. At The Kyoto College of Graduate Studies for Informatics, I would like to use the property of general-purpose algorithms to find interesting problems and solve them with you all.

Responsible Subject

  • System Theory
  • Honors Master Thesis

Field of Specialization

  • Algorithms, Computational Complexity, Optimization and Its Application

Business Performance


  • The Yonezawa Award of the IEICE (Institute of Electronics, Information and Communication Engineers)
  • Operations Research Society of Japan Literature Award (Operations Research Society of Japan)
  • Sawaragi Thesis Award (System Control Information Society)
  • IEICE Paper Award (Institute of Electronics, Information and Communication Engineers)
  • Editor's Choice Award (5 volumes) (Discrete Applied Mathematics)
  • Operations Research Society of Japan Award for Excellence (Operations Research Society of Japan)
  • The Japan Association for Mathematical Sciences Academic Award (JAMS Prize) (Japan Association of Mathematical Sciences)
  • The Japan Society of Scheduling Science Award (Institute of Scheduling)
  • Kondo Award (Operations Research Society of Japan)
  • Institute of Electronics, Information and Communication Engineers Award for Achievement (Institute of Electronics, Information and Communication Engineers)

Academic papers, International Conference Papers, etc.

  • Ibaraki, Imahori, Nonobe, Sobu, Uno, Yagiura: An iterated local search algorithm for the vehicle routing problem with convex time penalty functions, Discrete Applied Mathematics, Vol. 156, pp. 2050 -2069, 2008
  • Kataoka, Ibaraki "One-Way Proposal for Laboratory Assignment and Its Mathematical Consideration", The Operations Research Society of Japan, Japanese Journal, 51, pp. 71, -93, 2008.
  • Matsumoto, Miwa, Ibaraki: Scheduling of corrupted paper production, European Journal of Operational Research, Vol. 192, pp. 782 -792, 2009
  • Hashimoto, Ezaki, Yagiura, Nonobe, Ibaraki, Lokketangen: A set covering approach for the pickup and delivery problem with general constraints on each route, Pacific Journal of Optimization, Vol. 5, pp. 185 -202, 2009
  • Umetani, Yagiura, Imahori, Imamichi, Nonobe, Ibaraki: Solving the irregular strip packing problem via guided local search for overlap minimization, ITOR (International Transactions in Operational Research), Vol. 16, pp. 661 -683, 2009
  • Ibaraki, A personal perspective on problem solving by general purpose solutions, ITOR (International Transactions in Operational Research), to appear
  • Accumu | Kyoto Computer Gakuin Alumni Association bulletin

In addition, approximately 400 papers


  • Nagamochi, Ibaraki, Algorithmic Aspects of Graph Connectivity, Cambridge, 2008
  • 'Mathematics of optimization', Kyoritsu Publishing, 2011
  • 'Algorithms and Data Structures in C', Aum Inc., 2014

In addition, approximately 10 books