Fumitaka Uchio

Ubiquitous Earthquake Observation System Using Wireless Sensor Devices

Japan suffers from a high number of earthquakes, so the technology for an earthquake observation is highly demanded. One of information on an earthquake is seismic intensity information which is measured with seismic intensity meters and is announced by the media such as TV. The seismic intensity is a value observed at a location where a seismic intensity meter is placed. This means that the seismic intensity shows wide area information such as administrative districts, e.g., city, town or village. However sites where equal seismic intensity was observed would not necessarily suffer the same damage, because damage depends on the type of construction and on the nature of the seismic motion. Therefore, it is difficult to estimate the individual damage in personal area. In order to measure all the locations, it is necessary to place huge number of seismic intensity meters. In the paper, we develop the system which can observe an earthquake by using wireless sensor network technology. We use wireless nodes equipped with acceleration sensors. The system can provide useful information to predict the individual damage.

Improving 3D Imagery with Variable Convergence and Focus Accommodation for the Remote Assessment of Fruit Quality

This paper shows and discusses the implementation of new ideas we propose with the aim to overcome the visual discomfort that arises when using 3D visualization. Our proposal can be summarized as the improvement of 3D visualization by replicating the way human eyes see, in other words, the increase of human-like perception. We do so by extracting reality information from stereo image pairs and process them in order to improve the final 3D image before displaying it to the user. We describe the techniques used to extract information from stereo images as well as the techniques created to manipulate them in order to produce human-like perception with the aim of reducing visual discomfort in users of the stereo visualization system. We also describe the results of a preliminary evaluation that strongly suggests the effectiveness of these techniques

Beacon Scheduling in Receiver-Initiated MAC Protocols for Low-Delay and Energy-Efficient WSNs

Wireless Sensor Networks (WSNs) should collect sensing data quickly without increasing the energy consumption in order to deal with various applications, particularly delay-sensitive applications. This paper proposes a method to schedule beacon transmissions for receiver-initiated MAC protocols, which are promising energy efficient protocols, to improve data collection delay. The key idea of the proposed method is scheduling beacon timings in the sequence of distance from leaf node to the root (i.e., sink) node so that data frames are forwarded to the sink node with small duration staying at each node. Each sensor node selects a time slot to send beacon in distributed manner based on their distances (i.e. hop counts) from the sink node. In addition, each node autonomously adjusts its beacon timing to avoid frame collisions. Computer simulations show that the proposed method can collect data in a shorter time with less energy consumption than conventional beacon scheduling methods for receiver-initiated MAC protocols.

Measurement of Brain Activity on Force Adjustment Skill Acquisition by using EEG

Abstract Human beings perform various motion ranging from simple motion to advanced motion. In addition, sensory information is used as a feedback information of the motion state during operations which require fine adjustment. It is necessary for performing advanced motion to acquire the corresponding skills. In order to learn such skills efficiently, it is necessary to construct a skill learning system. Grasping skill acquisition status is effective for the skill learning system. Currently, there is no other method than evaluating skill acquisition status by using learners’ task scores. However, this method may not be enough to evaluate skill acquisition status. On the other hand, brain has the function of motion commands and sensory acceptance when moving the body. Therefore, it might be possible to sufficiently evaluate skill acquisition status by using the changes of brain activity. In the paper, we measured the changes of EEG accompanying learning on force adjustment skill. The obtained EEG data was filtered to remove some noise using Band-pass filter, and then it was transformed into a frequency component by FFT, and the ratio of α wave and β wave was calculated in the EEG data. In addition, we computed EEG coherence between the electrodes of near the frontal association cortex and the electrodes of near the primary motor cortex, between electrodes of near the frontal association cortex and electrodes of primary somatosensory cortex. As a result, the characteristics of the skill acquisition stage could be confirmed from the change of the ratio of α wave and β wave, increase and decrease of the coherence values.

Packet Scheduling and Access Priority Control for QoS and Fairness in Wireless LAN

Abstract In recent years, the increasing demand for multi-media communication, even in the wireless mobile environment overcrowding, QoS (Quality of Service) is important. In such environment, since many mobile stations (STAs) are using the same channel, it occurs the problem of unfair channel access time and downlink channel. In this paper, we propose a scheme to achieve a good balance of QoS, fairness and downlink/uplink traffic asymmetry by the combined operation of channel access priority control and packet scheduling with require modification only to AP and require no changes in STAs.

Dynamic QoS control function of video communication for remote technical consultation system

The purpose of this study is to develop a dynamic QoS (Quality of Service) control function for Remote Technical Consultation System. The Remote Technical Consultation System realizes technical consultation using video communication tool through narrow band networks. The proposed function can dynamically control size and quality of video images according to users demands and purposes. The user does not need to adjust QoS parameters by using the proposed function during performing remote technical consultations. Furthermore, the proposed function can transmit video images effectively for an assigned network by controlling QoS parameters to fit video images into the network. We developed the dynamic QoS control function and added this function to video tool for the Remote Technical Consultation System. We experimented on three different bandwidth networks using the developed function. From experimental results, we verified that the proposed function works finely on any bandwidth and transmits video images to the best on the assigned network bandwidth.