Okamoto Takashi

J-GLOBAL         Last updated: Nov 20, 2017 at 16:02
 
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Name
Okamoto Takashi
E-mail
takashi.okamotosensy.ai
Affiliation
SENSY Inc.
Job title
Director / Chief Research Officer / SENSY AI Research Laboratory Representative
Degree
Ph. D. (Engineering)(Keio University)
Research funding number
40451752

Research Areas

 
 

Academic & Professional Experience

 
Oct 2017
 - 
Today
Director / Chief Research Officer / SENSY AI Research Laboratory Representative, SENSY Inc.
 
Apr 2014
 - 
Sep 2017
Associate Professor, Graduate School of Engineering, Chiba University
 
Apr 2007
 - 
Mar 2014
Assistant Professor, Graduate School of Engineering, Chiba University
 

Published Papers

 
K. Toyoda, T. Okamoto, S. Koakutsu
Proc. of SICE Annual Conference 2017   805-810   Sep 2017   [Refereed]
D. Ito, T. Okamoto, S. Koakutsu
Proc. of SICE Annual Conference 2017   811-816   Sep 2017   [Refereed]
M. Yoshida, S. Koakutsu, T. Okamoto
IEEJ Trans. Electronics, Information and Systems   137(9) 1279-1285   Sep 2017   [Refereed]
N. Takase, T. Okamoto, R. Suzuki, T. Iisaka, C. Nakazawa, E. Aiyoshi
IEEJ Trans. Electronics, Information and Systems   137(8) 1024-1035   Aug 2017   [Refereed]
The liberalization of electricity retail sales of Japan for all customers including households was begun on April, 2016. In this paper, the retail power supplier operational planning against the FIT imbalance special system in the electricity reta...
C. Wang, S. Koakutsu, T. Okamoto, F. Qian
IEEJ Trans. Electronics, Information and Systems   137(5) 759-767   May 2017   [Refereed]
The learning automaton (LA) team model has been proposed as one method for modeling multi-agent systems. It is modeled as a non-cooperative game of learning automata. In this model, each LA operates independently from each other, and there exists ...
C. Wang, S. Koakutsu, T. Okamoto, F. Qian
IEEJ Trans. Electronics, Information and Systems   137(2) 333-334   Feb 2017   [Refereed]
K. Yoshida, T. Okamoto, S. Koakutsu
SICE Journal of Control, Measurement, and System Integration   9(6) 234-241   Nov 2016   [Refereed]
The selfish routing game is a mathematical model to represent the behavior of selfish players who select a path in a congested network. In the equilibrium solution search on the selfish routing game, the amount of flow passing through each path is...
Y. Kobayashi, T. Okamoto, S. Koakutsu
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2016   4525-4531   Oct 2016   [Refereed]
The visualization of the Pareto optimal solution set is one of important issues of the decision-making process on the multi-objective optimization problem. The Pareto optimal solution visualization method using the self-organizing maps (SOM) is on...
N. Suzuki, T. Okamoto, S. Koakutsu
Journal of Advanced Computational Intelligence and Intelligent Informatics   20(5) 691-704   Sep 2016   [Refereed]
K. Yoshida, T. Okamoto, S. Koakutsu
Proc. of SICE Annual Conference 2016   813-819   Sep 2016   [Refereed]
K. Hagio, S. Koakutsu, T. Okamoto
IEEJ Transactions on Electronics, Information and Systems   136(8) 1230-1236   Aug 2016   [Refereed]
N. Norimatsu, S. Koakutsu, T. Okamoto
IEEJ Transactions on Electronics, Information and Systems   136(7) 955-962   Jul 2016   [Refereed]
In recent years a study of evolvable hardware (EHW) which can adapt to new and unknown environments attracts much attention among hardware designers. EHW is reconfigurable hardware and can be implemented combining reconfigurable devices such as FP...
K. Inakazu, S. Koakutsu, T. Okamoto
IEEJ Transactions on Electronics, Information and Systems   136(7) 1017-1018   Jul 2016   [Refereed]
In recent years, the study of time-series processing using Neural Networks has been attracted attention. Pulsed Neural Networks (PNNs) are suitable for time-series processing because they have integrator elements in themselves. Recurrent Neural Ne...
H. Watanabe, N. Takase, T. Okamoto, K. Seki
IEEJ Transactions on Electronics, Information and Systems   136(5) 746-757   May 2016   [Refereed]
Recently, the introduction of the battery has been investigated in the electric power system. The purpose of the introduction of the battery is the system stabilization against the voltage fluctuation and the frequency fluctuation caused by the in...
Analysis of the optimization benchmark problem for series-parallel switching of photovoltaic modules under various conditions
T. Okamoto, T. Hayashi
Proc. of IEEJ International Workshop on Sensing, Actuation, Motion Control, and Optimization 2016   IS2-1   Mar 2016   [Refereed]
An optimization benchmark problem based on the energy plant model in the smart-community
R. Suzuki, T. Okamoto
Proc. of IEEJ International Workshop on Sensing, Actuation, Motion Control, and Optimization 2016   IS2-4   Mar 2016   [Refereed]
K. Yoshida, T. Okamoto, S. Koakutsu
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2015   3023-3029   Oct 2015   [Refereed]
The selfish routing problem is a mathematical model to represent the behavior of the selfish players who select a path in a congested network. In the selfish routing problem, Braess's paradox shows that there exists a case that more network resour...
SUZUKI, Naoto, OKAMOTO Takashi, KOAKUTSU, Seiichi
IEEJ Transactions on Electronics, Information and Systems   135(7) 908-919   Jul 2015   [Refereed]
The visualization of the Pareto optimal solution set is one of important issues of the multi-objective optimization. The Pareto optimal solution visualization method using the self-organizing maps is one of promising visualization methods. This me...
N. Takase, T. Okamoto, S. Koakutsu
Proc. of SICE Annual Conference 2015   284-291   Jul 2015   [Refereed]
H. Watanabe, T. Okamoto, R. Suzuki, T. Jintsugawa, E. Aiyoshi
Proc. of SICE Annual Conference 2015   292-299   Jul 2015   [Refereed]
C. Wang, F. Qian, S. Koakutsu, T. Okamoto
Proc. of SICE Annual Conference 2015   300-305   Jul 2015   [Refereed]
N. Suzuki, T. Okamoto, S. Koakutsu
Proc. of IEEE Congress on Evolutionary Computation   2556-2564   May 2015   [Refereed]
Overview of optimization benchmark problems for industrial applications and review of conventional problems
T. Okamoto
Proc. of the 1st IEEJ international workshop on sensing, actuation, and motion control   IS1-1   Mar 2015   [Refereed]
Formulation and solutions for daily operation scheduling problem of water supply pump
K. Yokokawa, T. Okamoto, A. Kawagoe, Y. Ueno, K. Mori
Proc. of the 1st IEEJ international workshop on sensing, actuation, and motion control   IS1-4   Mar 2015   [Refereed]
An introduction of the energy plant operational planning problem: A formulation and solutions
R. Suzuki, T. Okamoto
Proc. of the 1st IEEJ international workshop on sensing, actuation, and motion control   IS1-5   Mar 2015   [Refereed]
A. Hironaka, T. Okamoto, S. Koakutsu, H. Hirata
SICE Journal of Control, Measurement, and System Integration   8(1) 34-43   Jan 2015   [Refereed]
In the multi-objective optimization problem that appears naturally in the decision making process for the complex system, the visualization of the innumerable solutions called Pareto optimal solutions is important issue. This paper focuses on the ...
T. Okamoto
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2014   576-582   Oct 2014   [Refereed]
A design method of complex network growth model robust over the cascade failure
H. Mizuno, T. Okamoto, S. Koakutsu
Proc. of SICE Annual Conference 2014   1206-1209   Sep 2014   [Refereed]
NAKAMOTO Ryo, OKAMOTO Takashi, KOAKUTSU Seiichi, HIRATA Hironori
Transactions of the Society of Instrument and Control Engineers   49(11) 1037-1046   Nov 2013   [Refereed]
A complex network design method that finds a desired network structure can become one of strong tools in large-scale system designs. In the complex networks with flows, such as the power grid and the computer networks, the cascade failure attacks ...
WATANABE Hideki, KOKUTSU Seiichi, OKAMOTO Takashi, HIRATA Hironori
IEEJ Transactions on Electronics, Information and Systems   133(10) 1976-1982   Oct 2013   [Refereed]
In recent years a study of the evolvable hardware (EHW) which can adapt to new and unknown environments attracts much attention among hardware designers. EHW is reconfigurable hardware and can be implemented combining reconfigurable devices such a...
T. Okamoto, E. Aiyoshi
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2013   3516-3522   Oct 2013   [Refereed]
T. Okamoto, H. Hirata
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2013   3529-3536   Oct 2013   [Refereed]
T. Okamoto, H. Hirata
Proc. of SICE Annual Conference 2013   564-570   Sep 2013   [Refereed]
H. Mizuno, T. Okamoto, S. Koakutsu, H. Hirata
Proc. of SICE Annual Conference 2013   571-576   Sep 2013   [Refereed]
OKAMOTO Takashi, HIRATA Hironori
Engineering Optimization   45(3) 311-336   Mar 2013   [Refereed]
This article proposes a new constrained optimization method using a multipoint type chaotic Lagrangian method that utilizes chaotic search trajectories generated by Lagrangian gradient dynamics with a coupling structure. In the proposed method, mu...
OKAMOTO Takashi, HIRATA Hironori
Applied Soft Computing   13(2) 1247-1264   Feb 2013   [Refereed]
This paper proposes a new global optimization method called the multipoint type quasi-chaotic optimization method. In the proposed method, the simultaneous perturbation gradient approximation is introduced into a multipoint type chaotic optimizati...
MIZUNO Haruki, OKAMOTO Takashi, KOAKUTSU Seiichi, HIRATA Hironori
Proc. of SICE Annual Conference 2012   1525-1531   Sep 2012   [Refereed]
Many systems that can be modeled using network structures appear in various fields such as informatics, social science, economics, ecology, biology, and engineering. If these systems can be modeled as complex network systems, a complex network des...
OKAMOTO Takashi, HANAOKA Yuya, AIYOSHI Eitaro, KOBAYASHI Yoko
IEEJ Transactions on Electronics, Information and Systems   132(7) 1116-1127   Jul 2012   [Refereed]
In this paper, we consider a multi-objective optimization method in order to obtain a preferred solution for the buffer material optimal design problem in the high-level radioactive wastes geological disposal. The buffer material optimal design pr...
OKAMOTO Takashi, HIRATA Hironori
Transactions of the Society of Instrument and Control Engineers   48(3) 125-133   Mar 2012   [Refereed]
OKAMOTO Takashi, HIRATA Hironori
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2011   1765-1770   Oct 2011   [Refereed]
In this study, we propose a new constrained optimization method using the quasi-chaotic optimization method (Q-COM) with the exact penalty function and the Sequential Quadratic Programming (SQP). The Q-COM, which has been proposed recently, is a g...
OKAMOTO Takashi, HIRATA Hironori
Proc. of SICE Annual Conference 2011   952-956   Sep 2011   [Refereed]
In this study, we propose a new optimization method based on the quasi-chaotic optimization method for constrained mixed integer optimization problems. The quasi-chaotic optimization method has been proposed recently as a new global optimization m...
YAMAMOTO Kenji, KOAKUTSU Seiichi, OKAMOTO Takashi, HIRATA Hironori
Electronics and Communications in Japan   94(7) 27-34   Jul 2011   [Refereed]
Neural networks are widely applied to information processing because of their nonlinear processing capability. Digital hardware implementation of neural networks seems to be effective in the construction of neural network systems in which real-tim...
MIZUNO Haruki, OKAMOTO Takashi, KOAKUTSU Seiichi, HIRATA Hironori
IEEJ Transactions on Electronics, Information and Systems   131(5) 966-975   May 2011   [Refereed]
A complex network design method that finds a desired network structure can become one of strong tools in large-scale system designs. Conventional complex network design methods only tackle static networks, that is, they do not consider the growth ...
AIYOSHI Eitaro, MAKI Atsushi, OKAMOTO Takashi
Mathematics and Computers in Simulation   81(7) 1518-1526   Mar 2011   [Refereed]
This paper proposes a Nash equilibrium model that applies continuous time replicator dynamics to the analysis of oligopoly markets. The robustness of the proposed simple Nash equilibrium model under the simultaneous constraints of allocation of pr...
ISHII Yoshinao, OKAMOTO Takashi, AIYOSHI Eitaro
IEEJ Transactions on Electronics, Information and Systems   131(3) 626-634   Mar 2011   [Refereed]
Particle Swarm Optimization (PSO), which has attracted attention as a global optimization method in recent years, has a drawback in that sustainable search cannot be performed until the end of computation due to its strong convergence trend. In th...
Global optimization using a multi-point type quasi-chaotic optimization method without initial sampling parameter tuning
OKAMOTO Takashi, HIRATA Hironori
Proc. of Joint 5th International Conference on Soft Computing and Intelligent Systems and 11th International Symposium on Advanced Intelligent Systems   1603-1608   Dec 2010   [Refereed]
HIRAOKA Sodo, OKAMOTO Takashi, AIYOSHI Eitaro
Electrical Engineering in Japan   173(2) 42-54   Nov 2010   [Refereed]
Particle Swarm Optimization (PSO), which has attracted a great deal of attention as a global optimization method in recent years, has the drawback that continuous search based on its excellent dynamic characteristics cannot be performed stably unt...
OKAMOTO Takashi, AIYOSHI Eitaro, HAMADA Kenichiro
Transactions of the Society of Instrument and Control Engineers   46(11) 642-650   Nov 2010   [Refereed]
OKAMOTO Takashi, HIRATA Hironori
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2010   804-809   Oct 2010   [Refereed]
In this study, we propose a new global optimization method in which the simultaneous perturbation gradient approximation is introduced into a multi-point type chaotic optimization method. The multi-point type chaotic optimization method, which has...
OKAMOTO Takashi, HIRATA Hironori
Proc. of SICE Annual Conference 2010   833-837   Aug 2010   [Refereed]
In this study, we propose a new global optimization method in which the simultaneous perturbation gradient approximation is introduced into the draining method. The draining method is an unconstrained global optimization method which utilizes a ch...
IGUCHI Syota, KOAKUTSU Seiichi, OKAMOTO Takashi, HIRATA Hironori
IEEJ Transactions on Electronics, Information and Systems   130(7) 1213-1218   Jul 2010   [Refereed]
In recent years, the study of hardware implementation of Neural Networks (NN) has been getting more important. In particular, Block-Based Neural Networks (BBNN) which are one of NN have been attracted attention. However, the conventional BBNN are ...
OKAMOTO Takashi, HIRATA Hironori
IEEJ Transactions on Electronics, Information and Systems   130(1) 39-49   Jan 2010   [Refereed]
Optimization problems in which multiple objective functions are optimized simultaneously are called “multi-objective optimization problem”. Multi-objective optimization problems appear naturally in the decision making process for complex systems. ...
OKAMOTO Takashi, HIRATA Hironori
Proc. of IEEE Int. Conf. on Systems, Man, and Cybernetics 2009   4009-4016   Oct 2009   [Refereed]
In this study, we propose a new chaotic global optimization method using the Lagrangian method to solve a nonlinear constrained optimization problem. Firstly, we explain the convergence behavior of the first order method regarding convexity of the...
OKAMOTO Takashi, HIRATA Hironori
Proc. of ICROS-SICE Int. Joint Conf. 2009   Proc. of ICROS-SICE Int. Joint Conf. 2009 741-746   Aug 2009   [Refereed]
As one of the global optimization methods to solve constrained optimization problems, we have proposed a chaotic Lagrangian method which utilizes chaotic search trajectories generated in a coupled gradient dynamics with respect to the augmented La...
AIYOSHI Eitaro, MAKI Atsushi, OKAMOTO Takashi
Proc. of The 18th World IMACS Congress and MODSIM09 International Congress on Modelling and Simulation   1100-1106   Jul 2009   [Refereed]
Aiyoshi and Maki (2009) proposed a Nash equilibrium model applying continuous time replicator dynamics to the analysis of oligopoly markets. This paper considered a game problem under the simultaneous constraints of the allocation of product and m...
TAMASHIMA Daisuke, KOAKUTSU Seiichi, OKAMOTO Takashi, HIRATA Hironori
IEEJ Transactions on Electronics, Information and Systems   129(7) 1339-1347   Jul 2009   [Refereed]
Profit Sharing is one of exploitation oriented reinforcement learning methods and aims to adapt a system to a given environment. In Profit Sharing, an agent learns a policy based on the reward that is received from the environment when it reaches ...
OKAMOTO Takashi, AIYOSHI Eitaro
Electrical Engineering in Japan   165(4) 67-75   Dec 2008   [Refereed]
In this paper, we propose a new multiagent discrete gradient chaos model using a coupling structure which PSO has. Concretely, first, we introduce a multiagent-type optimization model whose agents search autonomously with the discrete gradient cha...
YAMAMOTO Kenji, KOAKUTSU Seiichi, OKAMOTO Takashi, HIRATA Hironori
IEEJ Transactions on Electronics, Information and Systems   128(7) 1137-1142   Jul 2008   [Refereed]
Neural Networks (NN) are widely applied to information processing because of its nonlinear processing capability. Digital hardware implementation of NN seems to be effective in construction of NN systems in which real-time operation and much furth...
HIRAOKA Sodo, OKAMOTO Takashi, AIYOSHI Eitaro
IEEJ Transactions on Electronics, Information and Systems   128(7) 1143-1153   Jul 2008   [Refereed]
Particle Swarm Optimization (PSO), which has attracted a great deal of attention as a global optimization method in recent years, has a drawback in that its continuous search based on its excellent dynamic characteristics can not be executed stabl...
OKAMOTO Takashi, AIYOSHI Eitaro
Journal of Global Optimization   41(2) 219-244   Jun 2008   [Refereed]
In the present paper, we propose a new multipoint type global optimization model using a chaotic dynamic model and a synchronization phenomenon in nonlinear dynamic systems for a continuously differentiable optimization problem. We first improve t...
OKAMOTO Takashi, AIYOSHI Eitaro
Transactions of the Society of Instrument and Control Engineers   42(2) 118-127   Feb 2007   [Refereed]
In this paper, we discuss continuous game problems for which a normalization constraint (unit simplex constraint) constrains each player’s decision-making. These problems can be classified into two types by their constraints. For one type, the sim...
WATANABE Yuki, OKAMOTO Takashi, AIYOSHI Eitaro
IEEJ Transactions on Electronics, Information and Systems   126(12) 1559-1568   Dec 2006   [Refereed]
In this paper, we propose a new global optimization method “Draining Method” which uses a tuning of the bifurcation characteristic of the discrete gradient chaos model by an objective function transformation. Specifically, firstly, we show that a ...
OKAMOTO Takashi, AIYOSHI Eitaro
Proc. of SICE-ICASE Int. Joint Conf. 2006   2190-2195   Oct 2006   [Refereed]
We have proposed "draining method (DM)". DM is based on the discrete gradient chaos model (DGCM) and the objective function transformation which is developed by the analysis of DGCM. Applying DM to typical benchmark problems, we have confirmed its...
OKAMOTO Takashi, AIYOSHI Eitaro
IEEJ Transactions on Electronics, Information and Systems   126(7) 857-864   Jul 2006   [Refereed]
In this paper, we propose a new multi-agent discrete gradient chaos model using a coupling structure which PSO has. Concretely, firstly, we introduce a multi-agent type optimization model whose agents search autonomously with the discrete gradient...
OKAMOTO Takashi, AIYOSHI Eitaro
IEEJ Transactions on Electronics, Information and Systems   124(9) 1888-1895   Sep 2004   [Refereed]
Optimization methods by using chaos dynamics are interesting as a class of global optimization methods by which the global minimum can be obtained without trapping in local minima. The chaos dynamics are classified into discretized gradient models...
OKAMOTO Takashi, AIYOSHI Eitaro
Transactions of the Institute of Systems, Control and Information Engineers   16(12) 662-669   Dec 2003   [Refereed]
Optimization methods by using chaos dynamics are interesting as a class of global optimization methods by which the global minimum can be obtained without trapping in local minima. The chaos dynamics are classfied into discretized gradient models ...

Misc

 
AIYOSHI Eitaro, OKAMOTO Takashi, KOBAYASHI Yoko
Atomoσ : journal of the Atomic Energy Society of Japan   54(3) 201-204   Mar 2012
AIYOSHI Eitaro, OKAMOTO Takashi, KOBAYASHI Yoko
Atomoσ : journal of the Atomic Energy Society of Japan   54(2) 133-136   Feb 2012
AIYOSHI Eitaro, OKAMOTO Takashi, KOBAYASHI Yoko
Atomoσ : journal of the Atomic Energy Society of Japan   54(1) 57-60   Jan 2012
AIYOSHI Eitaro, OKAMOTO Takashi, KOBAYASHI Yoko
日本原子力学会誌 = Journal of the Atomic Energy Society of Japan   53(11) 776-776   Nov 2011
AIYOSHI Eitaro, OKAMOTO Takashi, KOBAYASHI Yoko
Atomoσ : journal of the Atomic Energy Society of Japan   53(11) 777-781   Nov 2011
OKAMOTO Takashi
計測と制御 = Journal of the Society of Instrument and Control Engineers   47(6) 506-511   Jun 2008

Books etc

 
Basis of optimization method — Comprehension through dynamics and implementation
E. Aiyoshi, T. Okamoto, K. Yasuda (Part:Joint Work)
Morikita Publishing   Dec 2014   ISBN:462704271X
Electrical engineering handbook (7th edition)
The Institute of Electrical Engineers of Japan Ed. (Part:Contributor, Part 7, Section 6.2 and 6.4)
Ohmsha   Sep 2013   

Research Grants & Projects

 
JSPS: Grants-in-Aid for Scientific Research (C)
Project Year: Apr 2016 - Mar 2019    Investigator(s): Okamoto Takashi
Development of optimization methods using nonlinear dynamics for applications to real problem
JSPS: Grants-in-Aid for Scientific Research (C)
Project Year: Apr 2013 - Mar 2016    Investigator(s): Okamoto Takashi
Ministry of Education, Culture, Sports, Science and Technology: Grants-in-Aid for Scientific Research(若手研究(B))
Project Year: 2010 - 2012    Investigator(s): Takashi OKAMOTO
Ministry of Education, Culture, Sports, Science and Technology: Grants-in-Aid for Scientific Research(若手研究(B))
Project Year: 2008 - 2009    Investigator(s): Takashi OKAMOTO
In this study, we theoretically analyzed the optimization methods using coupled nonlinear dynamics in which multiple search points driven by nonlinear dynamics implement optimization. Furthermore, we studied an organization of the optimization met...
Ministry of Education, Culture, Sports, Science and Technology: Grants-in-Aid for Scientific Research(基盤研究(C))
Project Year: 2007 - 2009    Investigator(s): Eitaro AIYOSHI
In order to realize mechanisms of diversification and intensification in search for an optimal solution as strategies to provide adaptability to various structures and robustness against the problem scale, the new type of global optimization algor...