Member introduction
Hiroaki Umehara
(Research manager)
Degree
Ph.D. (Science)
Research theme
My research focuses on understanding multi-scale dynamics of neural network systems aimed at improving measurement techniques of neural activity. Missing links between microscopic and macroscopic models of neuron-level and brain-wave dynamics have to be bridged in order to reveal detailed information signals of neural activity and brain function from noninvasive measurement such as electroencephalography. Computational approaches that derive from a statistical-mechanics framework are central to the modeling of these signals. In particular, my main focus is currently on collective dynamics.
Prior to 2008, my dominant research domain was in the area of analytical mechanics and astronomical dynamics, including control and measurement of spacecraft orbits. I still maintain continued interest in this area, which I integrate with my research on the analysis of neural dynamics.
Education
1992 B.E. Department of Physics, Keio University
1994 M.S. Graduate School of Science and Engineering, Waseda University
1998 Ph.D. School of Mathematical and Physical Science, The Graduate University for Advanced Studies
Employment
1998-2001 Researcher, Communications Research Laboratory (currently, National Institute of Information and Communications Technology; hereafter, NICT)
2002-2006 Senior Researcher, Space Cybernetics Group, NICT
2002-2006 Senior Researcher, Space Cybernetics Group, NICT
2003-2004 Visiting Fellow, Department of Aerospace Engineering, University of Glasgow
2006-2007 Planning Manager, Strategic Planning Office, NICT
2008-2009 Senior Researcher, Space Communication Group, NICT
2009-2011 Senior Researcher, Biological ICT Group, NICT
2011-2013 Research Manager, Brain ICT Laboratory, Advanced ICT Research Institude, NICT
2013-2017 Research Manager, Brain Imaging Technology Laboratory, Center for Information and Neural Networks (CiNet), NICT
2017- Research Manager, Neural Information Engineering Laboratory, CiNet, NICT
Publications
Research papers
- Umehara, H., Okada, M. & Naruse, Y. Sequential Bayesian filters for estimating time series of wrapped and unwrapped angles with hyperparameter estimation. J. Phys. Soc. Jpn 87, 034005 (2018).
- Kushida, Y., Umehara, H., Hara, S. & Yamada, K. Momentum exchange impact damper design methodology for object-wall-collision problems. J. Vib. Control Article first published online: April 17, 2017.
- Umehara, H., Okada, M., Teramae, J. & Naruse, Y. Macroscopic neural mass model constructed from a current-based network model of spiking neurons. Biological Cybernetics 111, 91-103 (2017).
- Ihara, A.S., Ihara, S. A, Mimura, T., Soshi, T., Yorifuji, S., Hirata, M., Goto, T., Yoshinime, T., Umehara, H. &Fujimaki, N. Facilitated lexical ambiguity processing by transcranial direct current stimulation over the left inferior frontal cortex. Journal of Cognitive Neuroscience 27:1,26-34 (2015).
- Naruse, Y., Takiyama, K., Okada, M., Umehara, H. & Sakaguchi, Y. Phase shifts in alpha-frequency rhythm detected in electroencephalograms influence reaction time. Neural Networks 62, 47-51 (2015)
- Fujimaki, N., Terazono, Y., Ihara, S. A., Hayakawa, T., Matani, A. & Umehara, H. Accuracy of estimating strengths of dipole moments from a small number of magnetoencephalographic trial data. Brain Topography 27, 635-647 (2014).
- Naruse, Y., Takiyama, K., Okada, M. & Umehara, H. Statistical method for detecting phase shifts in alpha rhythm from human electroencephalogram data. Physical Review E 87, 042708 (2013)
- Leibnitz, K., Shimokawa, T., Umehara, H. & Murata, T. Topological Comparison of Brain Functional Networks and Internet Service Providers. IEICE Transactions on Communications , E95-B, 1539-1546 (2012).
- Ihara, A., Wei, Q., Matani, A., Fujimaki, N., Yagura, H., Nogai, T., Umehara, H. & Murata, T. Language comprehension dependent on emotional context: A magnetoencephalography study. Neuroscience Research 72, 50-58 (2012).
- Umehara, H., Takahashi, M., Otsubo T. & Kubo-oka, T. Scan by monitoring a pair of points - Optical survey method for near-geosynchronous orbits. Trans. JSASS Space Tech. Japan 3, 13-22 (2005)
- Nishinaga, N., Ogawa, Y., Takayama, Y., Takahashi, T., Kubo-oka, T. & Umehara, H. Reconfigurable communications satellite: SoftSAT. Space Communications 19, 149-158 (2005)
- Umehara, H. & McInnes, C. R. Penalty-function guidance for multiple-satellite cluster formation. Journal of Guidance Control And Dynamics 28, 182-185 (2005)
- Umehara, H. & Tanikawa, K. Improvement of the triple-encounter criterion. Publ. Astron. Soc. Japan 53, 693-697 (2001)
- Umehara, H. Potential-function guidance forming eccentricity separation of satellites with continuous thrust. Trans. Japan Soc. Aero. Space Sci. 44, 127-129 (2001)
- Umehara, H. & Tanikawa, K. Binary and triple collisions causing instability in the free-fall three-body problem. Celest. Mech. Dyn. Astron. 76, 187-214 (2000)
- Umehara, H. & Tanikawa, K. Orbital distribution arbitrarily close to the homothetic equilateral triple collision in the free-fall three-body problem with equal masses. Celest. Mech. Dyn. Astron. 74, 69-94 (1999)
- Tanikawa, K., Umehara, H. Oscillatory orbits in the planar three-body problem with equal masses. Celest. Mech. Dyn. Astron. 70, 167-180 (1998)
- Tanikawa, K., Umehara, H. & Abe, H. A search for collision orbits in the free-fall three-body problem: I. Numerical procedure. Celest. Mech. Dyn. Astron. 62, 335-362 (1995)
Conference presentations
- Umehara, H. & McInnes, C. R. Quasi-Linear Optimization for Multiple-Spacecraft Clustering. 56th International Astronautical Congress of the International Astronautical Federation (2005)
- Umehara, H. Ground-Based Optical Scan and Parallel Orbit Determination of Near Geosynchronous Objects. 21st International Communications Satellite Systems Conference and Exhibit (2003)