Controlling multiple agents in parallel is an important challenge in human-robot interaction, with growing applications in remote collaboration, telepresence, and multi-agent coordination. However, empirical work on distributed embodiment remains limited, particularly in scenarios where independently controlled avatars operate in distinct environments. To address this gap, we propose the concept of Dual Body Sensation (DBS): a novel theoretical construct of distributed embodiment, describing a state in which a single operator simultaneously experiences embodiment for two independent robots in distinct environments during their control. We conducted a within-subject experiment to investigate the cognitive feasibility of DBS using a $2\times 3$ factorial design that varied visual presentation (independent view, superimposed view) and tactile presentation (no tactile, bilateral tactile, unified tactile). The results indicated that DBS emerged across all conditions and was significantly enhanced under the unified tactile condition. The combination of the superimposed view and unified tactile conditions also increased the sense of body ownership and the sense of agency, while the superimposed view condition reduced cybersickness and cognitive load. These findings provide empirical support for DBS and inform the design of future multi-agent interaction systems that support flexible distribution of bodily control and awareness.

To capture a remote 3D image, conventional stereo cameras attached to a robot head have been commonly used. However, when the head and cameras rotate, the captured image in buffers is degraded by latency and motion blur, which may cause VR sickness. In the present study, we propose a method named TwinCam in which we use two 360° cameras spaced at the standard interpupillary distance and keep the direction of the lens constant in the world coordinate even when the camera bodies are rotated to reflect the orientation of the observer's head and the position of the eyes. We consider that this method can suppress the image buffer size to send to the observer because each camera captures the omnidirectional image without lens rotation. This paper introduces the mechanical design of our camera system and its potential for visual telepresence through three experiments. Experiment 1 confirmed the requirement of a stereoscopic rather than monoscopic camera for highly accurate depth perception, and Experiments 2 and 3 proved that our mechanical camera setup can reduce motion blur and VR sickness.

Pathogenic infection is usually invisible. Thus, we hardly care of preventing it in the daily life. We aimed to develop a virtual reality system to experience bidirectional infections using vision and tactile sensations; Users are infected by an avatar, and they do infect the avatar. When the avatar coughs toward a user, a cloud of visualized pathogen-droplets jet out and strike the user and objects on a table. At the same time, vibrations are presented to the user's chest. When the user coughs toward the avatar, the cough was detected by a throat microphone, and a cloud of visualized pathogen jets out. The avatar tries to avoid it unpleasantly, but infected. He is getting sick in bad face color. This system enables us to experience pathogenic infection with multimodal sensations in both perspectives (infected and infecting). Thus, it may contribute to increasing user's knowledge of infection and to facilitating prevention behaviors such as wearing a hygiene mask.

The present study investigates the augmentation effect of airflow on the sensation of a virtual reality walk. The intensity of cutaneous sensation evoked by airflow during the real and virtual walk was measured. The airflow stimulus was added to the participant with passive vestibular motion and visual presentation. The result suggests that the sensation of walking was strongly increased by adding the airflow stimulus to the vestibular and optic presentations. The cutaneous sensation of airflow was perceived higher for the sitting participant than during a real walk in both a single and the combined stimuli. The equivalent speed of airflow for the sitting participant was lowered from the airflow speed in the real walk.

This paper describes a passive stimulation of a body to evoke a walking sensation using a vestibular and haptic device while the real body of the user is sitting. It imparts a pseudo body image to the user through the real (physical) body of the user as a part of the virtual reality (VR) display system. The created walking sensation was evaluated by nine factors to analyze the complex nature of the walking sensation.

We aim to develop a virtual-reality system that records a person's walking experience and gives other users the experience of his/her walking. We recorded stereo motion images of video cameras on a person's forehead with synchronous acceleration data of ankles. Then, we presented stereo motion images on a HMD with synchronous vibrations on soles of observer's feet. Observers reported better experience of vection, walking, and tele-existence from stereo images with vibrations than without vibrations. We recorded walking experiences of different body sizes including a child (130 cm tall) and those of a dog. Observers can partly experience child's walking and even dog's running.

The Five Senses Theatre project was established for the development of a basic technology that enables the user to relive a spatial motion of other persons as if the user him/her-self experienced it in person. This technology aims to duplicate a bodily experience performed in the real space and to pass it to the other person. In other words, the user experiences another person's body that moved in a real space as if the user moved in that real space. The spatial motion may be a walking tour to the world heritage, a legend run of a top athlete, and etc. More specifically, the system creates the sensation of a self-body motion without a voluntary motion of the user by providing physical motion to the real body. The sensation of self-body motion is generated by not only a visually induced vection but proprioceptive and tactile sensations of the body passively evoked. The Five Senses Theatre provides multisensory stimuli to the user to make use of the user's body as medium to project the valuable experience from others to the user's cognition. The research issues include the following: 1) Cognitive mechanism of passive stimulation perceived as an active motion sensation (pseudo agency), and body ownership transfer (virtual body). 2) Device development of the mutisensory display system, rendering/projection algorithms, and a lifelog data system.

The present paper describes the system to present a pseudo-walking sensation to a sitting participant. The vibration was added to the heel and toe to imitate cutaneous sensation of the sole during walking. The sound of footsteps was also provided to the participant through headphones simultaneously. In this sound presentation, we used a spatial sound of footsteps of another walker as well as own footstep sound. Another walker's sound was moved along several trajectories in a VR space. We conducted an experiment to elucidate the effect of third person's footstep sound moved differently on the walking sensation of a participant. The result showed that third person's sound enhanced not only walking sensation but also translational sensation of a sitting participant. Furthermore, the effect was the highest when third person's sound came from front to backward of the participant in a VR space.

This paper describes rendering characteristics of a virtual walk by a motion seat. The motion seat creates a small body motion in three dof (lift, roll, and pitch directions) to make the user feel as if the user him-/herself is walking despite sitting own body. We consider the actual self body is a medium to render the virtual body to share experiences of others by using the motion seat as part of the multisensory display. After setting the motion to optimally present a walking sensation, basic characteristics of perception levels of the virtual walk by the seat motion were measured and compared with those for a real walk. The result indicated that the perception levels of the virtual walk were around those of a real walk.

This paper describes an approach to interpolate the wind direction and velocity using two fans. Firstly, maps of the angle and velocity of the wind in relation to the speeds of the two fans are created. It was found that changes in the speeds of the two fans in the interpolation were not necessarily linear to the directional angles from the fans. Next, in the generation of wind, the speeds of the fans are inversely referenced from the maps using the target direction and velocity. An experiment confirmed that wind can be generated from an intermediate direction between the two fans. Through an evaluation using subjects, it was proven that a change in the direction of the wind could be recognized to some extent, although great differences in accuracy were observed among individuals.

We conducted a user study to clarify whether a tactile flow created by a matrix of vibrators in a seat pan simultaneously presented with an optical flow in peripheral vision enhances the perceived forward velocity of self-motion. A brief tactile motion stimulus consisted of four successive rows of vibration, and the inter-stimulus onset between the tactile rows was varied to change the velocity of the tactile motion. The experimental results show that the velocity of self-motion is significantly overestimated for rapid tactile flows and underestimated for slow tactile flows, compared with only optical flow or non-motion vibrotactile stimulation conditions.

In this paper we propose a novel approach to augmenting human memory based on spatial and graphic information using wearable and smartphone devices. Mnemonics is a technique for memorizing a number of unstructured items that has been known for more than two millennia and was used in ancient Greece. Although its utility is remarkable, acquiring the skill to take advantage of mnemonics is generally difficult. In this study we propose a new method of increasing the effectiveness of classic mnemonics by facilitating the process of memorizing and applying mnemonics. The spatial electronic mnemonics (SROM) proposed here is partly based on an ancient technique that utilizes locations and images that reflect the characteristics of human memory. We first present the design of the SROM as a working hypothesis that augments traditional mnemonics using a portable computer. Then an augmented virtual memory peg (vMPeg) that incorporates a graphic numeral and a photograph of a location is introduced as a first implementation for generating a vMPeg. In an experiment, subjects exhibited remarkable retention of the vMPegs over a long interval. The second phase of placing items to remember on a generated vMPeg was also examined in a preliminary experiment, which also indicated good subject performance. In addition to evaluating the SROM by anylysing the scores for correct recall, a subjective evaluation was performed to investigate the nature of the SROM.

In this paper, we describe a novel voice menu presentation method, the vCocktail, designed for efficient human-computer interaction in wearable computing. This method is devised to reduce the length of the serial presentation of voice menus by introducing spatiotemporal multiplexed voices with enhanced separation cues. Perception error in judging voice direction was measured first to determine appropriate directions in which and interval angles at which menu items were placed allowing the user a clear distinction among the multiple items. Then voice menu items were presented under spatiotemporally multiplexed conditions with several different settings of spatial localization, number of words, and onset interval. The results of the experiments showed that the subjects could hear items very accurately with localization cues and appropriate onset intervals. In addition, the proposed attenuating menu voice and crosstype spatial sequence of presentation increased the correct answer ratio effectively improving distinction between menu items. A correct answer ratio of 99.7 % was achieved in the case of four-item multiplexing when an attenuating voice and a 0.2 sec onset interval were used with the cross-type spatial sequence.

This paper describes a wearable electronic mnemonics, the iFlashBack system that promotes human memorization process for the action the user performed in the real-world. The goal of the system is to exploit unlimited capacity of the human brain for storing the variety of information, by assisting memorization using recorded video and related information captured during interaction process to real-world objects. Memorization reinforcement is achieved by drawing attention, promoting rehearsal by flashing a video of interaction, and organizing memory by providing relevant information. The action of the user is captured by a cap-mounted miniature camera, an RFID reader, and arm posture sensors worn by the user. For video-aided rehearsal, a small HMD presents the captured scenes immediately after the user's interaction behavior and/or at appropriate times in the user's activity. We conducted basic experiments to demonstrate our idea. Two memory tasks - to change cup positions within grids and to memorize random dot images - were performed by subjects. The results suggested that the iFlashBack system could reinforce memorization of the user's action by motion-controlled video aided rehearsal.

The authors describe a new design of haptic texture display consisting of fifty vibratory pins that evoke a virtual touch sensation of textured surfaces contacted to the user's fingerpad. A pin drive mechanism was fabricated by adjusting a natural frequency to expand the displacement of a piezoelectric actuator efficiently. An improved control system enabled fine amplitude changes in 200 steps. Sensation intensity was scaled and indicated by a power function of pin amplitude. As a fundamental evaluation data, we measured the difference threshold of an object's spatial frequency presented on the display, regarding four intensity waveforms. Moreover, matching tests between real and virtual textures were performed to evaluate the quality of presentation.