Faculty Members


(Professor/Division of Environmental Studies)

Department of Socio-Cultural Environmental Studies/Communication Engineering and Pervasive Computing

Career Summary

1984: B.E. in Electrical Engineering, University of Tokyo
1989: Ph. D. in Electrical Engineering, University of Tokyo
1989: Lecturer, Institute of Industrial Science, University of Tokyo
1992: Associate Professor, Institute of Industrial Science, University of Tokyo
1996: Visiting Scholar, University of California, San Diego
2001: Associate Professor, Center for Spatial Information Science, University of Tokyo
2011: Professor, Center for Spatial Information Science, University of Tokyo
2013: Professor, co-appointed at Center for Socio-Global Informatics, Institute of Industrial Science, University of Tokyo

Educational Activities

Graduate school: Network Architecture, Urban Computing

Research Activities

Our research interests used to be high-speed networks and related applications on them. In the early days, we developed switch architecture suitable for WDM systems. Most significantly, we proposed non-blocking switching networks that have an arbitrary number of stages and photonic switching networks composed of only wavelength filters and the wave length converters. We also developed a fast wavelength assignment algorithm for WDM. On the application side, we have focused on the sense of touch or haptics and developed fundamental techniques to transmit haptics over networks, with particular focus on media synchronization, delay control, and bandwidth compression. These can be applied to tele-operations and other "emerging" network applications.

Recently, we?fve noticed the importance of location in network applications and have conducted various related research, including algorithms to control networks by using the physical locations of the nodes. We have also developed a seamless and accurate positioning system using RFID tags and dead reckoning.

In the 21 century, we started researching sensor networks, including the adaptive assignment of time slots for energy saving, geocasting algorithms to propagate necessary information only to the designated geographical area, and control algorithms for robot sensor networks.

Recently, due to the widespread usage of sensor-rich smartphones, we are studying various issues regarding user participatory sensing, where smartphones are used as mobile sensors. We are also developing various participatory sensing applications such as mHealth systems and digital archiving of cityscapes. We?fre also interested in how to utilize the sensed data and are trying to more deeply analyze the activity and environment of urban areas in many respects.


1. Shunsuke Aoki and Kaoru Sezaki, ''Negative Surveys with Randomized Response Techniques for Privacy-aware Participatory Sensing'', IEICE Transactions on Communications, Vol. E97-B, No. 04, 2014.
2. S. Han, S. Han, and K. Sezaki: "Development of an Optimal Vehicle-to-Grid Aggregator for Frequency Regulation ", IEEE Transaction on Smart Grid, Vol. 1, No. 1, pp. 65-72 (2010).
3. H. Chen, Q. Shi, R. Tan, H. V. Poor, and K. Sezaki: ''Mobile element assisted cooperative localization for wireless sensor networks with obstacles'', IEEE Transaction on Wireless Communications, Vol. 9, No. 3, pp. 956-965 (2010).
4. K. Hikichi, H. Morino, I. Arimoto, K. Sezaki, and Y. Yasuda, "The Evaluation of Delay Jitter for Haptics Collaboration over the Internet", IEEE Global Telecommunications Conference (Globecom' 02), pp.1492-1496, (2002).
5. T. Nagata, S. Inoue, K. Sezaki, and Y. Yasuda, "A non-blocking architecture of wavelength division multiplexing photonic switching network", IEICE Transactions B-1, pp. 130-137, (1997) (in Japanese).

Other Activities

Steering committee member, IEEE COMSOC eHealth Committee
Editor, Journal on Semantic Computing
Editor, Journal of IIEEJ
Steering committee member, GIS Association of Japan

Future Plan

The main focus of our research group is communication engineering and related applications on networks. A huge amount of data regarding the present state of urban areas is being collected from sensor networks and social networks, which are a kind of "social sensor", and used for various analyses of the present status. We believe such information is indispensable for predicting the future and for various decision/policy making tasks, as well. These research areas require knowledge of other research fields, and we are therefore pursuing interdisciplinary research with the help of the different research communities.

Messages to Students

As graduate school students, deep thinking on your research is of utmost importance. Even though your research results may not help you right away, forming the correct attitude now will certainly benefit you in the future. At the same time, you should adopt a very broad perspective as researcher. Having both of these is crucial in this rapidly changing modern research world.