Kazuyuki Fujita

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Two methods that use advanced control technology in order to improve the performance of AC servomotor systems are described. The first method is the detection of instantaneous speed using an observer. This method provides good response in speed control because it is possible to detect exactly the speed without detection dead time over a wide range of(More)
We propose two novel map navigation techniques, called Anchored Zoom (AZ) and Anchored Zoom and Tilt (AZT). In these techniques, the zooming and tilting of a virtual camera are automatically coupled with users' panning displacements so that the anchor point determined by users always remains in a viewport. This allows users to manipulate a viewport without(More)
Recently, small and highly efficient personal digital assistants such as cellular phone are developed, and mobile communications are being indispensable in life. The ad hoc network is observed in such circumstances. However, conventional routing algorithms that keep the optimum routing is difficult to perform flexible routing in dynamic topology network,(More)
In Multi-Agent Reinforcement Learning, each agent observe a state of other agents as a part of environment. Therefore, the state space is exponential in the number of agents and learning speed significantly decrease. Modular Q-learning [6] needs very small state space. However, the incomplete observation involves a decline in the performance. In this paper,(More)
—In this paper, we investigate the effectiveness of the records of user's activities in Twitter, which is a popular social media, for estimating user's depressive tendency. We construct multiple regression model to estimate user's depressive tendency from the frequencies of words used by the user. We perform experiments to estimate participants' depressive(More)
We propose a room-shaped information environment called Ambient Suite that enhances communication among multiple participants. In Ambient Suite, the room itself works as both sensors to estimate the conversation states of participants and displays to present information to stimulate conversation. Such nonverbal cues as utterances, positions, and gestures(More)
A base-isolated building may sometimes exhibit an undesirable large response to a long-duration, long-period earthquake ground motion and a connected building system without base-isolation may show a large response to a near-fault (rather high-frequency) earthquake ground motion. To overcome both deficiencies, a new hybrid control system of base-isolation(More)