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Search Results: 1 - 10 of 7202 matches for " Hiroshi Watanabe "
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Comfort in observing stereoscopic images reduced by vibration stimuli  [PDF]
Hiroshi Watanabe, Hiroyasu Ujike
Health (Health) , 2012, DOI: 10.4236/health.2012.411157
Abstract: Numerous studies have been conducted to illuminate the effect of image factors to reduce unexpected influence of stereoscopic images on healthy visual experience. In this paper, we introduce changes in the psychological and physiological indexes of observers of a stereo- scopic image disturbed by vibration stimuli. Forty-four healthy university students participated in the experiment. A programmable vibration table generated two types of vibrations (5 Hz and 20 Hz) and provided intermittent vibration stimuli to a stereoscopic projector installed on a vibration table. Our results showed that the frequency of vibration stimuli has a strong impact in evaluating the local comfort of subjects. Our results also showed that the indexes of visual fatigue increased after observation independent of the frequency. The activity status of the autonomic nervous system as a physiological index significantly increased after observing 3D images with vibration stimuli although the vibrational frequency did not have a significant effect on the activity status.
Psychological and physiological effects of stereoscopic movies of real-world scenes containing improper three-dimensional settings  [PDF]
Hiroshi Watanabe, Hiroyasu Ujike
Health (Health) , 2013, DOI: 10.4236/health.2013.57148
Abstract:

By using psychological and physiological indicators, the effects on the body of three-dimensional (3D) movies containing improper settings were evaluated with 139 university students. The experiment consisted of two sessions: 1) a 3D movie containing improper 3D settings was compared with a 2D movie containing only the rightside images presented to both eyes, and 2) the original 3D movie was compared with the same 3D movie altered to contain improper 3D settings. The results of this experiment demonstrated clear deterioration of the subjective psychological indicators (degree of motion sickness after watching the movies and comfort level at 1-min intervals during the movie) with respect to the 3D movie containing improper settings. On the other hand, the physiological indicators (LF/HF ratio indicating the status of the autonomic nervous system) changed as a result of watching a 3D movie, but were unaffected by the presence or absence of improper 3D settings.

Thermoelectric Properties of Misfit Layered Bismuth-Based Rhodium Oxides, (Bi,Pb)2Sr2Rh2Oy  [PDF]
Takuya Watanabe, Hiroshi Irie
Journal of Materials Science and Chemical Engineering (MSCE) , 2018, DOI: 10.4236/msce.2018.67011
Abstract: Rhodium oxides, including a misfitlayered structure with alternate stacking of a rock salttype layer and a hexagonal RhO2 layer, are expected to have good thermoelectric properties. Among them, the thermoelectric properties (electrical conductivity (σ), Seebeck coefficient (S), Figure of merit (ZT) and calculated thermal conductivity (κ) by S, σ, ZT, and absolute temperature (T)) of bismuth-based rhodium oxides ((Bi1-x,Pbx) 2Sr2Rh2Oy, x = 0 and 0.02, hereafter BSR and BPSR, respectively) were investigated. In comparison with Bi2Sr2Co2Oy (BSC) at 700°C, S and κ enhanced (increased S, 110 (BSR) and 105 μV K-1 (BPSR) from 85 μV K-1 (BSC) and decreased κ, 0.32 (BSR) and 0.50 W m-1 K-1 (BPSR) from 1.75 W m-1 K-1 (BSC)), whereas σ decreased (15 (BSR) and 31 S cm-1 (BPSR) from 70 S cm-1 (BSC)). BPSR reached the highest ZT value of 0.067 at 700°C, compared to those of 0.056 (BSR) and 0.027 (BSC).
Non-equilibrium Relaxation Analysis on Two-dimensional Melting
Hiroshi Watanabe
Physics , 2008, DOI: 10.1143/PTPS.178.41
Abstract: The melting transition in the hard-disk system is considered. Non-equilibrium relaxation analysis of the six-fold bond-orientational order parameter has been carried out. The critical point between the hexatic and the fluid phase is determined on the basis of the dynamic scaling hypothesis. The value of the critical exponent $\eta$ is determined from the fluctuation of the order parameter at the criticality as $\eta = 0.25(2)$ which is consistent with the prediction by the Kosterlitz-Thouless-Halperin-Nelson-Young theory.
Markovian Approximation for the Nosé--Hoover method and H-theorem
Hiroshi Watanabe
Physics , 2008, DOI: 10.1143/JPSJ.77.103001
Abstract: A Langevin equation with state-dependent random force is considered. When the Helmholtz free energy is a nonincreasing function of time (the H-theorem), a generalized Einstein relation is obtained. A stochastic process of the Nos\'e--Hoover method is discussed on the basis of the Markovian approximation. It is found that the generalized Einstein relation holds for the Fokker--Planck equation associated with the stochastic Nos\'e--Hoover equation. The present result indicates that the Nos\'e--Hoover dynamics coarse-grained with time satisfies the H-theorem and therefore works as a heat bath.
Triviality of hierarchical O(N) spin model in four dimensions with large N
Hiroshi Watanabe
Physics , 2003, DOI: 10.1023/B:JOSS.0000028073.49354.9d
Abstract: The renormalization group transformation for the hierarchical O(N) spin model in four dimensions is studied by means of characteristic functions of single-site measures, and convergence of the critical trajectory to the Gaussian fixed point is shown for a sufficiently large N. In the strong coupling regime, the trajectory is controlled by the help of the exactly solved O(\infty) trajectory, while, in the weak coupling regime, convergence to the Gaussian fixed point is shown by power decay of the effective coupling constant.
Difficult Sudoku Puzzles Created by Replica Exchange Monte Carlo Method
Hiroshi Watanabe
Physics , 2013,
Abstract: An algorithm to create difficult Sudoku puzzles is proposed. An Ising spin-glass like Hamiltonian describing difficulty of puzzles is defined, and difficult puzzles are created by minimizing the energy of the Hamiltonian. We adopt the replica exchange Monte Carlo method with simultaneous temperature adjustments to search lower energy states efficiently, and we succeed in creating a puzzle which is the world hardest ever created in our definition, to our best knowledge. (Added on Mar. 11, the created puzzle can be solved easily by hand. Our definition of the difficulty is inappropriate.)
Comparison of Developmental Stages in Relation to Way Finding Behavior in an Immersive Virtual Reality Space  [PDF]
Hiroshi Watanabe, Tomohito Okumura, Eiji Wakamiya
Health (Health) , 2016, DOI: 10.4236/health.2016.85052
Abstract: To establish a proper evaluation method for spatial cognitive deficits and a form of developmental disorder, we have used an immersive virtual reality (VR) device to develop a game that involves actually walking through a VR space to search for a target object. In this paper, we presented the results of control experiment with 22 healthy elementary school students as participants. The complexity of the VR space was controlled according to the number of pillars present and whether an overall view was possible (controlled by the height of the pillars). For each set of conditions, 24 trials were performed, and the route and time taken to search for the target were recorded. The starting point was changed in each subsequent trial. Results showed that the search time decreased as the number of trials increase, suggesting a process whereby a cognitive map was formed. We also compared the present results to results from our previous experiment with university students using the same experimental conditions, and we discussed the influence of developmental stage on spatial cognition.
Coinhibitory Molecules in Autoimmune Diseases
Norihiko Watanabe,Hiroshi Nakajima
Clinical and Developmental Immunology , 2012, DOI: 10.1155/2012/269756
Abstract: Coinhibitory molecules such as CTLA-4, PD-1 and BTLA negatively regulate immune responses. Multiple studies indicate that the deficiency or mutation of coinhibitory molecules leads to the development of autoimmune diseases in mice and humans, indicating that the negative signals from coinhibitory molecules are crucial for the prevention of autoimmunity. In some conditions, the administration of decoy coinhibitory receptors (e.g., CTLA-4 Ig) or mAb against coinhibitory molecules suppresses the responses of self-reactive T cells in autoimmune diseases. Therefore, modulation of coinhibitory signals seems to be an attractive approach to induce tolerance in autoimmune diseases in humans where the disease-inducing self-antigens are not known. Particularly, administration of CTLA-4 Ig has shown great promise in animal models of autoimmune diseases and has been gaining increasing attention in clinical investigation in several autoimmune diseases in humans.
Coinhibitory Molecules in Autoimmune Diseases
Norihiko Watanabe,Hiroshi Nakajima
Journal of Immunology Research , 2012, DOI: 10.1155/2012/269756
Abstract: Coinhibitory molecules such as CTLA-4, PD-1 and BTLA negatively regulate immune responses. Multiple studies indicate that the deficiency or mutation of coinhibitory molecules leads to the development of autoimmune diseases in mice and humans, indicating that the negative signals from coinhibitory molecules are crucial for the prevention of autoimmunity. In some conditions, the administration of decoy coinhibitory receptors (e.g., CTLA-4?Ig) or mAb against coinhibitory molecules suppresses the responses of self-reactive T cells in autoimmune diseases. Therefore, modulation of coinhibitory signals seems to be an attractive approach to induce tolerance in autoimmune diseases in humans where the disease-inducing self-antigens are not known. Particularly, administration of CTLA-4?Ig has shown great promise in animal models of autoimmune diseases and has been gaining increasing attention in clinical investigation in several autoimmune diseases in humans. 1. Introduction The immune system has developed multiple mechanisms to prevent harmful activation of immune cells. One such mechanism is the balance between costimulatory and coinhibitory signals delivered to T cells. The B7-1 (CD80)/B7-2 (CD86)-CTLA-4 pathway is the best-characterized inhibitory pathway for T-cell activation [1–3]. Another inhibitory pathway involves programmed death-1 (PD-1), which interacts with PD-L1 (B7-H1) and PD-L2 (B7-DC) and negatively regulates T cell activation [1, 3, 4]. B and T lymphocyte attenuator (BTLA), the third coinhibitory molecule for T-cell activation, is a cell surface molecule with similarities to CTLA-4 and PD-1 [5]. The ligand for BTLA is herpesvirus-entry mediator (HVEM), a TNF receptor family protein, and the ligation of BTLA with HVEM attenuates T-cell activation [6–9]. Since these inhibitory coreceptors inhibit proliferation and cytokine production of T cells in vitro and in vivo, they are thought to play important roles in maintaining immunological homeostasis and tolerance [10–12]. Autoimmune diseases occur because of a failure of the immune system to maintain nonresponsiveness or tolerance to self-antigens. Accumulating evidence indicates that coinhibitory molecules are key in the prevention of autoimmune diseases, because a defect or a functional mutation in these molecules promotes autoimmunity and polymorphisms of these genes are associated with genetic susceptibility to autoimmune diseases in humans. Once an autoimmune disease developed, whether it is organ specific or nonorgan specific, in most cases corticosteroids and/or immunosuppressants are used for
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