Hiromitsu Kato

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Service systems in public spaces are now being developed by employing ubiquitous computers in these spaces. Such systems must provide services to end users with a wide range of motivations, including unmotivated users who do not actively use the available services. Context-awareness to support these users is thus an important requirement for this kind of(More)
The negatively charged nitrogen-vacancy (NV) centre exhibits outstanding optical and spin properties and thus is very attractive for applications in quantum optics. Up to now an active control of the charge state of near-surface NV centres is difficult and the centres switch in an uncontrolled way between different charge states. In this work, we(More)
Much business and technical attention is being paid to the potential for new services in a ubiquitous computing environment. One of the probable features of these services is ‘context -awareness’, which is made possible by using information from the physical environmental through sensors. This paper provides an overview of the opportunities for new services(More)
Bilayer graphene was synthesized at low temperature using surface wave microwave plasma techniques where poly(methyl metacrylate) (PMMA) and methane (CH4) were used as carbon sources. Temperature-dependent Hall effect measurements were carried out in a helium atmosphere. Sheet resistance, sheet carrier density and mobility showed weak temperature dependence(More)
We fabricated inversion channel diamond metal-oxide-semiconductor field-effect transistors (MOSFETs) with normally off characteristics. At present, Si MOSFETs and insulated gate bipolar transistors (IGBTs) with inversion channels are widely used because of their high controllability of electric power and high tolerance. Although a diamond semiconductor is(More)
We are trying to resolve privacy issues of monitoring cameras through the "Yaoyorozu Project," which is a research project based on a "transdisciplinary science and technology" approach. In this paper we describe technical issues that must be addressed to assure both privacy and monitoring availability. We describe the design and development of a system(More)
INTRODUCTION TRANSPORTATION of people is increasing as our society grows and the demand for railway services that can provide high-speed and high-capacity transportation is becoming greater. The number of train rides taken in Japan in 2006 was 22,243 million, more than anywhere else in the world by some margin, making Japan one of the world’s leading(More)
Security is one of the most critical issues in the field of ubiquitous computing (UbiComp). We have proposed a system architecture to organize distributed objects and to prevent an organized group from experiencing an intentional or accidental denial of services. Several research studies have investigated the use of a computationally rich environment, in(More)