Yohei Iwasaki

HASC2011corpus: towards the common ground of human activity recognition

Human activity recognition through the wearable sensor will enable a next-generation human-oriented ubiquitous computing. However, most of research on human activity recognition so far is based on small number of subjects, and non-public data. To overcome the situation, we have gathered 4897 accelerometer data with 116 subjects and compose them as HASC2011corpus. In the field of pattern recognition, it is very important to evaluate and to improve the recognition methods by using the same dataset as a common ground. We make the HASC2011corpus into public for the research community to use it as a common ground of the Human Activity Recognition. We also show several facts and results of obtained from the corpus.

Underground Positioning: Subway Information System Using WiFi Location Technology

We introduce a subway information system which utilize WiFi location technology for supporting a person in the underground. The system is composed of a mobile terminal with a WiFi device and a communication server. We have developed seven location aware applications for the mobile terminal. Each of the application helps the user with current location information. We have performed a demonstration experiment in the subway of Nagoya City with 35 subjects and got a positive acceptance of the system.

Azim: direction based service using azimuth based position estimation

Here, we propose a system named Azim that provides service based on both location and direction, which uses position estimation method based on azimuth data. In this system, a users position is estimated by having the user point to and measure azimuths of several markers or objects whose positions are already known. Because the measurements are naturally associated with some degree of error, the users position is calculated as a probability distribution. Since both the users position and azimuth data are obtained in this method, both sources of data are used to realize more advanced services such as identifying the object pointed to by a user. The proposed system utilizes a wireless LAN for supporting these advanced services. Finally, a prototype system was implemented using a direction sensor that combines a magnetic compass and accelerometer, and we exemplify the usefulness of our approach through an experiment.

Design, implementation and evaluations of a direction based service system for both indoor and outdoor

This paper describes a design, implementation and evaluations of a direction based service system named Azim, which utilizes both a position and a direction of a user. In this system, a users position is estimated by having the user point to and measure azimuths of several markers or objects whose positions are already known. Because the system does not require any other accurate position sensors nor positive beacons, it can be deployed cost-effectively. We have implemented a prototype system using a direction sensor that combines a magnetic compass and accelerometer. We have conducted experiments both indoor and outdoor, and exemplified that positioning accuracy by the proposed method is precise enough for a direction based service.

An Automatic Software Decentralization Framework for Distributed Device Collaboration

Recently, many low-profile devices with RF communication features have been developed such as sensor network nodes and one-chip microcomputers. This caused a variety of gadgets join to the wireless network. However, in order to realize collaborations between these devices, generally we have to develop complicated distributed software. In this paper, we propose an automatic software decentralization method, which converts a stand-alone software program into distributed software programs. In order to execute the generated software on these low-profile devices, we employ the programming language nesC for a decentralization target. We also have implemented applications with real hardware devices to exemplify that the proposed method successfully improves the ease of development.

Azim : Direction-Based Service System for Both Indoors and Outdoors

SUMMARY In this paper, we propose an advanced location-based service that we call a direction-based service, which utilizes both the position and direction of a user. The direction-based service enables a user to point to an object of interest for command or investigation. We also describe the design, implementation and evaluations of a direction-based service system named Azim. With this system, the direction of the user can be obtained by a magnetic-based direction sensor. The sensor is also used for azimuthbased position estimation, in which a user’s position is estimated by having the user point to and measure azimuths of several markers or objects whose positions are already known. Because this approach does not require any other accurate position sensors or positive beacons, it can be deployed costeffectively. Also, because the measurements are naturally associated with some degree of error, the position is calculated as a probability distribution. The calculation considers the error of direction measurement and the pre-obtained field information such as obstacles and magnetic field disturbance, which enables robust position measurements even in geomagnetically disturbed environments. For wide-area use, the system also utilizes a wireless LAN to obtain rough position information by identifying base stations. We have implemented a prototype system for the proposed method and some applications for the direction-based services. Furthermore, we have conducted experiments both indoors and outdoors, and exemplified that positioning accuracy by the proposed method is precise enough for a direction-based service.