Wataru Yamada

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In this paper, indoor propagation characteristics for TV white space (TVWS) frequency bands are studied. Measurements in the actual indoor environment are performed and described. An indoor propagation model for TVWS is developed, which is useful for evaluating secondary-secondary interference in TVWS scenarios, and its empirical parameters are derived(More)
The property of cloth changes when it gets wet. Especially, wet cloth sticks to objects being touched. When expressing a wet cloth in computer graphics, pseudo representation is often used. As existing research, [Gascon et al. 2010] added a constrain to the part of cloth where it touches the base object. This constraint is a force which makes the cloth(More)
A tag system is proposed that offers a practical approach to ubiquitous computing. It provides small and low-power tags that are easy to distribute; does not need a special device to read the tags (in the future), thus enabling their use anytime, anywhere; and has a wide reading range in angle and distance that extends the design space of tag-based(More)
The aim of this study is to develop an accurate and reliable method to estimate field distributions in train cars so as to advance radio link design of wireless LANs operating inside the cars. This paper describes effects of reflected waves due to tunnel wall and/or train passing on opposite track on propagation characteristics inside the high-speed train(More)
This paper describes a method to extract local event information from the micro-blog service Twitter. Twitter holds innumerable user-posted short messages called tweets that cover various topics including local events. Our proposal is composed of three steps: 1) extract tweets related to local events from local tweets by the Support Vector Machine (SVM)(More)
This paper proposes new techniques to simulate a MIMO propagation channel using the ray-tracing method for the purpose of decreasing the computational complexity. These techniques simulate a MIMO propagation channel by substituting the propagation path between a particular combination of transmitter and receiver antennas for all combinations of transmitter(More)