Shigeru Tajima

Wearable key: device for personalizing nearby environment

This paper describes a system that allows users who obtain a wearable ID key to personalize dynamically ubiquitous computers by simply touching them. We call the concept of providing personalized service by touch Active Personalization. For active personalization, users only have to wear a digital key and do not have to carry around other computers. When users touch ubiquitous computers with their wearable key, the keyholes of the ubiquitous computers recognize their IDs and can personalize the computers. We developed a new network technology between keys and keyholes that enables digital information to be carried through a persons body based on a near-field technology we call TouchNet.

Peer-to-Peer Control System for DC Microgrids

We propose and implement a dc microgrid with a fully decentralized control system, using the ICT concept of network overlays and peer-to-peer (P2P) networks. Decentralization not only concerns the physical systems and control logic but also the control structure which provides the network infrastructure on which energy management is carried out. In this paper, we show how such decentralization can be achieved using P2P frameworks as underlying control structures and implemented a pure P2P to eliminate single points of failure. For this, a direct current open energy system made of the interconnection of standalone dc nanogrids is used as underlying microgrid. The power flows between nanogrids are controlled by a decentralized exchange strategy: each household can request or respond to energy deals with its neighbors without requiring system-wide knowledge or control. Using dc combined with a layered, modular software allows loose coupling which increases flexibility and dependability. The system has been implemented and tested on a full-scale platform in Okinawa including 19 inhabited houses. Real data analysis as well as simulations demonstrate improvements in self-sufficiency compared to other types of systems. Resilience against utility blackouts is proven in practice.

A Novel Power Supply System Based on a Packet Exchange Network Architecture

In this paper, we have proposed a new type of power supply system that uses a single pair of wires to provide various specifications of electric power. The IEEE 802.3af (a.k.a. Power over Ethernet) [6] is a technology that can transmit electricity over Unshielded Twisted Pair cables, however, this technology provides only 48 V DC and does not provide any networking functions. In contrast, our system abstracts electric power into packets and uses a network protocol to transmit them appropriately. We have designed our system to be flexible and extensible. Our motivation is to build a large- scale power supply network similar to the Internet. Hence, we have developed our MAC layer protocol on the basis of the Ethernet protocol which has strong affinity with Internet Protocol.