We investigated how hemodynamics in the brain behave using NIRS (Near Infrared Spectroscopy) while man using tool. The tools in our experiment were a pair of real scissors and virtual reality scissors. Such a virtual reality technology allows amount of feedback information to change. We tested with five male-subjects, right-handed. The results showed that when amount of feedback information, which was generated during cutting, was richer, the hemodynamics change of oxygenated hemoglobin was greater in prefrontal area of left hemisphere. This observation means that it is necessary to process integration of motor and sensory information during operation with tool in order to feel "reality".

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In this article, we propose an innovative technology of "Brain CAVE Interface". The electroencephalogram signals of steady-state visual evoked potentials, induced by virtual objects illuminated with constant frequencies, were recorded. Several pattern recognition techniques were investigated to discriminate between brain signals induced by one virtual object and that by another. Machine learning made a remarkable performance. The support vector machine with single trial data for 2.0 (1.0) seconds resulted in 94.6 (91.2) % of averaged recognition rate. This extended concept of non-invasive brain computer interface would enable us to realize intuitive and non-muscular manipulations of virtual objects. The promising visual evoked potentials in CAVE will be suggested in the viewpoint of direction controlling for walking application.

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Currentry, people have less commitments to communication in collaborative virtual environment compared to in face-to-face environment. One of the reasons is the difficulty of understanding how their own commitments are. To address this issue, we display EEG(electroencephalography) information to a virtual space with intuitive style - zoom in/out of whole virtual space. By evaluating this system, the results show that this system successfully provides an environment in which people have high-commitments to communication.

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In order to improve the daily activity classification with wireless accelerometers worn by people, we have evaluated how the daily activity classification performance depends on 1) the number of sensors and their bodily positions and 2) the sampling frequency. We have obtained the result that the highest classification performance of 10 kinds of daily activity is 89.9% when the accelerometers are installed in four positions (the both hands neck and both ankles) and SVM (Support Vector Machine) is used as a classifier. We have also obtained the result that the classification performance is 88.6% for the same accelerometer data except that they have been re-sampled from 50 Hz to 6.25 Hz. These results can be reflected to the wearable sensor design with less user load and longer working time.

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Optical topography (OT) seems suitable for applicative brain-machine interface, since it is non-invasive and very easy to handle and maintain. There are, however, only few studies to estimate subjects' cognitive situations by using it. Here, we tried to decode the visual stimuli that subjects viewed in detecting visual coherent motion by classification using support vector machine from cerebral hemodynamic responses measured by OT. We investigated the effect of spatiotemporal characteristics of OT signals on classification performances by manipulating temporal frequency filters and positions of optical fiber probes. Consequently, classification performances varied along with them. Therefore it was suggested that temporal frequency of cerebral hemodynamic changes would be different according to brain regions or types of cognitive processing.

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Magnetoencephalography (MEG) was used to investigate the brain mechanism of audio-visual predictive information processing and to propose a basic theory on optimal presentation of multimodal information in VR. After repetitive delivery of a specific visual-auditory pattern with a prior visual presentation, either a congruent or incongruent pattern with a deviant auditory part was presented to subjects (e.g., V_aA_a, V_aA_a, V_aA_a, V_bA_b/V_aA_b, ...). When they predicted a probable sound based on a visual cue, a congruent/incongruent pattern evoked smaller/larger auditory activity in the bilateral supratemporal areas, respectively. Since this so-called mismatch field (MMF) is considered to reflect unimodal change-detection process in the auditory sensory memory, the strength change suggests that a template, which is usually used in the process, is also created explicitly by visual information to detect incongruities earlier. We thus conclude that the essence of such crossmodal completion lies in the template creation.

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Recently, attention is being brought to exposure treatment methods using Virtual Reality for those suffering from panic disorder accompanied by agoraphobia. Overseas, contents for exposure treatment introducing Virtual Reality began development in the 1990s and positive evaluations are being made regarding its treatment methods and treatment effects. On one hand, there are still no cases developed professionally in Korea and even evaluations cases introduced into treatment are being made using contents developed overseas. For such reasons, this study has attempted to develop Virtual Reality Exposure contents which fully reflect Japan's culture and environment. Developed contents were focused on subway environments where avoidance was shown the most among patients receiving treatment in community hospitals. Contents were produced through Virtual Reality by modeling existing places and objects in their actual size to express a high sense of reality. Also, mutual interaction functions were strengthened to allow exposure suitable to the diverse symptoms of each patient. Although evaluations through this study are still in progress, changes in avoidance behavior regarding anxiety and fear are being confirmed and treatment effects are being verified through additional experiments.

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This paper describes an evaluation of inner effect of walking. By using a near infrared spectroscopy, activity of human brain can be measured while walking. In this study, two interfaces, a treadmill and a footpad-type locomotion interface were used as test beds. 15 subjects conducted some 1-minute gait trainings and their primary motor area, premotor cortex, and supplementary motor area were measured while these trainings. As a result, some different and common points between walking on these interfaces were found.

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The goal of our study is development of a "tactile mirror" for displaying tactile perception information. A point of distinctive difference between a tactile mirror and conventional tactile displays is that a tactile mirror possesses a feedback mechanism for acquiring the contact state information on the finger pad concerning not force but tactile perception sensation. The primary development concerns human static friction sensation. First, a control method and the structure of a tactile mirror are described. Second, simulation results using FEM for contact analysis and a ANN(Artificial Neural Network) for generating feedback signals are shown. Finally, experiments demonstrating that providing a feedback component accomplish accurate display of static friction sensation are shown.

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This paper proposes a new efficient, robust, BEM (Boundary Element Method) based method for simulating articulated 3D elastic objects' behaviors. The articulated elastic object consists of bones, elastic object primitives and joining surfaces. After transforming the bones by inverse kinematics, the elastic object primitives are deformed basically by the BEM. To reduce the computation cost and memory usage and to achieve robust deformations, this paper improves the BEM based module of the conventional method: more specifically, a new method for computing the displacements of the vertices in the joining surfaces. Experimental results show that the proposed model can be simulated 10 times as fast as the conventional model or faster, and that real time performances such as 60fps can be achieved even for models with 20,000 vertices. High quality simulations of different deformations including expansions and contractions are achieved using character type models.

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A pseudo-force-feedback method is proposed that induces tactile sense to each fingertip by its tightening. The concept of the method is limiting the display sense to tactile alone, in contrast to the conventional force-feedback devices stimulate both tactile and proprioceptive receptors by applying actual reaction force. The prototype device was controlled with open-loop controller with high-voltage initial acceleration pulse to reduce the device delay. The prototype device attained the tightening force up to 2.3N. The perceived reaction force sense by the users correlated with the applied contact force. The prototype two-fingered grasping device demonstrated that the wide range of virtual objects, from 10 to 70mm, were successfully recognized. The subjective sensation of grasping was more resemble to actual objects than the substitutive method using vibration.

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