Major Research Subjects of Sezaki, K. (2001-) Professor
Further information is available at http://www.mcl.iis.u-tokyo.ac.jp/
- Context aware services
This research aims at constructing an architecture for flexible
context aware services, where the intent of users are proactively
recognized and their activities are properly and comfortably supported.
Among them, physical location of users is the most important "context".
Thus, in this research we especially focus on the location dependent
routing and network services. While the conventional routing of
internet and PSTN both depend on the logical user address as IP
address and telephone number, we are studying the routing architecture
which depend on the physical location of the users and the intermediate
nodes. By using it, we can deliver necessary information to the
user of a specific physical location. We are also studying the
enhancement of this architecture to the multicast case which is
called geo-cast. By geo cast, we can deliver necessary information
to the users of a specific geographical region, say within 100m
from Tokyo station. Based on location dependent routing, various
network services can be provided. For example, in an emergency,
refuge alert can be promptly delivered to the proper geographical
location, which might help the mitigation of disaster such as
earthquake and fire.
- Haptic collaboration and its applications
Communication via networks has been based on voice and image media
for over 100 years. On the other hand, various haptic devices,
by which the sense of touch and force are sensed and fed back
to the users at the same time, is now available as commercial
products. Thus haptic communication is now becoming realistic
and applications using them are also emerging and expected as
one of the promising killer applications. However, since haptic
collaboration and communication have been studied mainly by researchers
of robotics, the effect of networks connection haptic devices
have been ignored. In other words, the networks have been treated
as ideal. But, in reality, the quality of the haptic collaboration
highly depends on the network impairments.
From this point of view, we are studying various issues related
to keeping the subjective quality of haptic applications as high
as possible under such network impairments as bandwidth limitation,
latency, jitter and loss of information. The examples are coding
of haptic media, media synchronization for the compensation of
the delay and jitter, various method for error correction including
dead-reckoning.
- Study on high-speed networks
We have been studying the various topics on the operation of very
high speed networks. As for the network elements, we are interested
in very high speed node systems as a very lager scale ATM switch
fabric and optical switch for WDM networks. From the viewpoint
of network planning, we proposed the optimization method of the
fiber network where the dominant traffic is broadband multicast/broadcast,
the dynamic distribution algorithm of VOD servers and fast wavelength
path assignment algorithm for WDM networks. We have been also
studying the protocol design of layered transmission and layered
multicast. Transparent media scaling by the combination of above
protocols and layered coding of images have been also proposed.
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