Yoshito Tobe

In this paper, we design and implement an sBike (Sensorized Bike) prototype to support cyclists by recognizing various riding states including going straight, turning right or left, meandering, and stopping. An Android phone, which is equipped with a gyro sensor, an accelerometer, and a GPS receiver, is mounted on the handle of bicycle to collect necessary data for analysis. Hidden Markov model (HMM) is adopted to recognize the riding states from raw sensor data. The experimental results show that the accuracy of recognition is as high as 98%. By knowing the riding states of cyclists, road conditions can be inferred and shared amongst users.

A Wireless Camera Node with Passive Self-righting Mechanism for Capturing Surrounding View | InTechOpen, Published on: 2010-08-12. Authors: Kuniaki Kawabata, Hideo Sato, Tsuyoshi Suzuki, et

Temperature in an urban area exhibits a complicated pattern due to complexity of infrastructure. Despite geographical proximity, structures of a group of buildings and streets affect changes in temperature. To investigate the pattern of fine-grained distribution of temperature, we installed a densely distributed sensor network called UScan. In this paper, we describe the system architecture of UScan as well as experience learned from installing 200 sensors in downtown Tokyo. The field experiment of UScan system operated for two months to collect long-term urban temperature data. To analyze the collected data in an efficient manner, we propose a lightweight clustering methodology to study the correlation between the pattern of temperature and various environmental factors including the amount of sunshine, the width of streets, and the existence of trees. The analysis reveals meaningful results and asserts the necessity of fine-grained deployment of sensors in an urban area.

Geographic routing has been paid much attention in query-based sensor networks since sensed data inherently pertain to the location of the data. In conventional geographic routing, the destination of a message should be the location of a node. However, this is not suitable for sensors that cover a wide or directed sensing area such as cameras. To cope with this problem, we propose a modified geographic routing scheme called SenriGan. SenriGan accommodates specifying a sensed point as a destination instead of using a location of a node. In this paper, we describe our proposed system architecture using image sensor networks and an implementation of its prototype.

Recently there has been a great deal of research on using mobility in sensor networks to assist their sensing tasks. In this paper, we propose a policy-based session control protocol for disruption tolerant sensor networks (DTSNs) called Billiards. In a DTSN, all messages are transported by the physical motion of participants (mobile nodes) in the network. When a large volume of data or continuous data is required to be transferred, there exists a problem determining how the data is fragmented and how the mobile nodes are formed for carrying the data to the destination. To overcome these issues, we propose a suitable method of session control which is determined based on a state of surrounding mobile nodes such as number, maximum-velocity and buffer-size. Billiards also takes a system policy of either delay minimization or energy efficiency into consideration. In this paper, we describe the protocol and model of Billiards and analyze the each model. We also show its effectiveness through experiments with utilizing mobile robots.

After the earthquake, it is very important to grasp the situation of the disaster area as soon as possible. This research, aims to develop a novel sensor node for gathering disaster information. Developed sensor node equips a double-spherical mechanism for setting the direction of build-in camera uniformly. It also has a small Linux computer, with GPS adaptor, wireless LAN and omni-directional camera an&so on. Therefore, the sensor node can transfer captured images with location and time information. In this paper, developed sensor node is introduced and its performance is experimented using prototype.