It is necessary to recognize the virtual area exactly and interact with 3D information intuitively to work smoothly in a virtual space. This study created a virtual reality (VR) game environment that integrated stereoscopic vision based on a binocular parallax by a head mounted display (HMD) with body motion measurement by a range image sensor. Also, to enhance immersion and operation feeling, we presented tactile information using a vibrotactile globe. We verified the usefulness of the operation by real-scale body motions, stereoscopic vision, and tactile information. From the results of experiments, we could confirm that stereoscopic vision improves the game impression, and the operation by real-scale body motions improves game scores in the VR game environment created.

The full body illusion (FBI) is an illusion of the self-ownership and self-agency towards an avatar that moves synchronously with one’s own body movement. Here we investigated the FBI using an avatar that moves with a short delay from the participant’s movement. Participants made their steps on the spot while watching a VR scene as if the avatar walked in a street either synchronously (100-ms delay) or asynchronously (400- or 700-ms delay) with their steps. The avatar was presented in either 1st-person or 3rd-person perspective. The result showed that the participants felt the sense of ownership only toward the avatar that moved synchronously in the 1st-person perspectives. Our results suggest that our body image can be projected on the avatar that is presented in the 1st-person perspective and moves synchronously with one’s own body.

It is difficult for humans to manipulate their virtual body in the immersive virtual system when its size is different from the real body. The authors assumed that this problem is caused by misfit of the body schema and have been working on the research of body schema calibration, which is the method to update the body schema to fit the virtual body. However, in the previous research, the survey of the basic characteristics of updating body schema has been limited to a narrow range in the extension direction. Therefore, in this paper, we have dealt with updating body schema in wider range in both extension and contraction direction, in order to clarify not only the characteristics of updating in the contraction direction but the limits of update. The results showed symmetry characteristics of body schema update in both directions, while the update effect deteriorated in case of extreme changes.

Human stability is an important sense that relates to human posture. If it can be presented the stability sense, it will improve the reality of virtual reality experience. In this study, in order to reproduce the projected center of gravity, which is one of the indices of stability, we conducted experiments to confirm the projected center of gravity from the replicated plantar reaction force when presented with the other’s plantar reaction force. A device to reproduce the other’s plantar reaction force and the center of gravity projection response system were used. We confirmed the projected center of gravity with an accuracy of 2 cm. Therefore, it is possible to estimate the center of gravity projection point and difficult to estimate when the foot reaction force was multiplied by 0.1.

In recent years, about 15% of the working population have mental disorders. It causes low productivity, absence, and unemployment due to illness. Treatment of mental disorders takes a long time, so routine precautions are essential. One of the ways to prevent mental disorders is to get healing through interaction with animals. However, this method has not been widely accepted due to the difficulties of handling animals. To solve these problems, in the previous study, we introduced a virtual pet as an alternative to animals by using virtual reality (VR) technology, which is three-dimensional stereoscopic, and we verified that this system gained short-term psychological and physiological benefits. However, it was unclear which factors positively affected users. Therefore, this paper investigates whether the virtual pet factor or body movement factor affected users’ psychological and physiological aspects. As a result of an experiment, it is confirmed that both the virtual pet factor and the body movement factor positively affect users. In addition, the user’s subjective evaluation implies that the interaction with a virtual pet’s interest in the system.

In this study, we propose a researcher recommendation model that considers the roles of principal researchers and co-researchers in research collaborations using a directed researcher network. The proposed model defines edge vectors between researchers, constructs the directed researcher network using the grants-in-aid for scientific research database, and outputs recommendation lists of lists of top-k researchers according to recommendation scores calculated by logistic regression. The recommendation accuracy of normalized Discounted Cumulative Gain (nDCG) @k for the proposed five baseline models are compared. Adamic/Adar, Hasan model, CCRec, Araki model, and LDAcosin are used as baselines. The experimental result shows that nDCG@k, recommendation accuracy, improves from the baseline models for recommendation of principal researchers who have belonged to the same institution. In the other models except CCRec, the nDCG@k by co-researchers recommendation is higher than that principal researchers recommendation; therefore, the difficulty of prediction is considered to be different. It suggests that the co-researchers recommendation may be easily predicted by considering directions of edges. The proposed model recommends researchers with a high average PageRank for the principal researchers recommendation. It also recommends researchers with a large number of collaborative researches. Due to the difference in the recommendation list between the proposed model and the Hasan model, it is possible to recommend a combination of multiple models when implementing as a recommender system. In the logistic regression analysis of features, it is confirmed that there is a difference in the odds ratio between the number of common principal researchers and the number of common co-researchers. These features can only be defined in directed graphs. It is indicated that the proposed model takes into account the differences between principal researchers and co-researchers.

To decrease the number of COVID-19 infectors, Ministry of Health, Labour and Welfare developed and released the COVID-19 contact-confirming application (COCOA) on 19th June 2020. Users of the application can know whether they contacted infectors who are/were positive of COVID-19 or not. If the contacted persons stay indoors, the number of new infectors can be decreasing. However, as of October 2020, the number of infectors of COVID-19 is increasing in Japan. Therefore, the additional function to decrease the number of infectors is necessary. In this paper, the function of the secondary indirect contact notification is proposed. In other words, the application informs whether they contacted infectors or not to not only the primary direct contact persons but also the secondary indirect contact persons. To verify the effectiveness of the additional function on decreasing infectors, we develop a simulator incorporating it. Herein, we report the simulator and effectiveness of the secondary indirect contact notification on decreasing infectors.

[Objective] The purpose of this study was to investigate the information processing process in the brain by cross-correlation analysis of brain waves after emotional stimulation with a smartphone. [Methods] The subjects were 23 healthy adults that were divided into two groups, namely stress and non-stress groups, via psychological examination. In the experiment, stimuli of relaxation, pleasant, unpleasant, pleasant sentence, and unpleasant sentence were displayed on a smartphone for the subject, and the brain waves were measured concurrently. To record the EEG data, the electrodes (19 channels) were placed according to the international 10/20 system. Coherence analysis was performed on the EEG, and the coherence values and time lag in 171 combinations among all channels in the alpha 1 band (8–10 Hz) were calculated. [Results] The time-lag between unpleasant, pleasant, and unpleasant sentences in the non-stress group was higher than that for the rest and pleasant stimuli. The stress group showed higher time-lag than the non-stress group at all stimulation times. [Discussion] The results imply that the stress group has slower information propagation compared to the non-stress group. Additionally, it can be suggested that text stimulation received from a smartphone has slow information propagation, regardless of its content.

There is a method of recognizing speech behavior based on information other than sound (silent speech recognition) as a method for speech communication in environments where speech cannot be used. Although there have been studies on the prediction of spoken words using electromyogram (EMG), information on emotional expressions such as syllable duration is lost. This study proposed a method for prediction the syllable duration of spoken words from EMG. The results of classification accuracy and average error show that the proposed method can predict the syllable duration.