Career Summary 
1989: B.Eng., Department of Thermal Engineering, Shanghai Jiao Tong University 1994: D.Eng., The University of Tokyo 19941999: Research Associate, Faculty of Engineering, The University of Tokyo 1999: Lecturer, Faculty of Engineering, The University of Tokyo 19992011: Associate Professor, Faculty of Engineering, The University of Tokyo 2011: Associate Professor, Graduate School of Frontier Sciences, The University of Tokyo




Educational Activities 
Graduate School: Simulation of Complex Systems (to be held) Undergraduate School: Continuum Models, System ModelingI (Fluid Mechanics and Heat Transfer), Mathematical Finance Department of Physics (Fudan University, Shanghai): Econophysics




Research Activities 
We are conducting research on the simulation of complex systems (SCS). Taking the 21st century's engineering problems as typical examples of complex systems, we aim to discover the mechanism of systems and solution of engineering problems by using SCS based on discrete models. 1) Modeling and simulation of financial markets. Financial markets are typical complex adaptive systems. We are conducting research on the simulation of single or coupled financial markets with agentbased models. Not only will complex phenomena occurring in the financial markets be reproduced, but the mechanism behind and the internal structures of the markets will be clarified. [Ref. (1)] 2) Experiments and multiagent simulations of behavioral game to clarify market principle. We have constructed a marketdirected resource allocation game (MDRAG) and carried out behavioral experiments and multiagent simulations of it. Very interesting results concerning the mechanism of the invisible hand as well as the necessary conditions for the invisible hand to work were obtained. [Ref. (3)]
Behavioral experiments of MDRAG game and construction of agentbased model for financial markets
3) Lattice Boltzmann modeling and simulation of lateral capillary phenomena. Lateral capillary phenomena are typical examples of complex physical systems. Interactions among particles residing in a liquidgas interface or a liquid film were studied with lattice Boltzmann simulations based on a unified discrete model, which is constructed by applying the discrete kinetic theory. We want to thoroughly investigate the physics of lateral capillary forces. [Ref. (4)] 4) Lattice Boltzmann modeling and simulation of multiphase viscoelastic flows. Multiphase flows with viscoelasticity are very complicated. A lattice Boltzmann model for this flow phenomenon was constructed by applying the springbeads model and discretizing the space of springbead orientations. With this model, we studied the rise of a single bubble in nonNewtonian fluid. [Ref. (6)]
Lattice Boltzmann simulation studies on complex fluids

Literature
1) Tomoko Ohi, Yasuhiro Hashimoto, Yu Chen and Hirotada Ohashi. "Simulation of Futures and Spot Markets by Using an AgentBased MultiMarket Model," Journal of Advanced Computational Intelligence and Intelligent Informatics, 15(2), pp. 204211, 2011. 2) Hidenori Komatsu, Yasuhiro Hashimoto, Yu Chen and Hirotada Ohashi, "Artificial embryogeny for network structures and its application for a robot generation task," Journal of Artificial Intelligence, 25, pp. 423432, 2010. (in Japanese) 3) Wei Wang, Yu Chen and Jiping Huang, "Heterogeneous preferences, decisionmaking capacity, and phase transitions in a complex adaptive system," PNAS (Proceedings of the National Academy of Sciences), 0811782106, 2009. 4) Junya Onishi, Atsushi Kawasaki, Yu Chen and Hirotada Ohashi. "Lattice Boltzmann simulation of capillary interactions among colloidal particles," Computers and Mathematics with Applications, 55(7), pp. 15411553, 2008. 5) Atsushi Kawasaki, Junya Onishi, Yu Chen and Hirotada Ohashi. "A lattice Boltzmann model for contact line motions," Computers and Mathematics with Applications, 55(7), pp. 14921502, 2008. 6) Junya Onishi, Yu Chen and Hirotada Ohashi. "Dynamic simulation of multicomponent viscoelastic fluids using the lattice Boltzmann method," Physica A, 362(1), pp. 8492, 2006. 7) Yuji Sakazaki, Shinnosuke Masuda, Junya Onishi, Yu Chen and Hirotada Ohashi. "The modeling of colloidal fluids by the realcoded lattice gas," Mathematics and Computers in Simulation, 72(26), pp. 184189, 2006.




Other Activities 
Atomic Energy Society of Japan (AESJ) The Japan Society for Industrial and Applied Mathematics (JSIAM)




Future Plan 
We are working hard in order to stand at the forefront of study on complex systems. In the future, while we shall continue basic research, research on application of SCS to realistic engineering problems, including environmental, economic and social systems, will also be launched.




Messages to Students 
Please join us in conducting exciting SCS research, no matter whether you are interested in complex physical systems, humancomposed social or economic complex systems, or any other kind of complex systems!





