With the growing presence of personal mobility vehicles and autonomous mobile robots in public spaces, pedestrian collisions have become an increasing concern, particularly because these devices operate quietly and often approach unnoticed. Traditional notification methods typically emphasize urgency through explicit and intense notifications, which often lead to psychological burden. To address this issue, this study proposes a method aimed at reducing sensory stimuli by using a virtual sound-absorbing wall. This approach leverages the human "obstacle sense", which is the ability to perceive objects based on changes in ambient sound blocked by their presence. A prototype system was developed in a virtual reality (VR) environment using a head-mounted display (HMD), where a virtual sound-absorbing wall appears in the direction of objects approaching from behind to enhance their perceived presence. The proposed method was compared to conventional notification methods in a VR environment, and its psychological impact was evaluated. Additionally, the impact of varying the angular width of the virtual sound-absorbing wall on detection rates was investigated. Results indicated that although the detection rate was lower than that of the conventional method, the proposed approach significantly reduced psychological burden. With the widest absorption angle condition, accuracy exceeding 90% was achieved in detecting the presence of the virtual sound-absorbing wall from directions other than directly behind.

The demand for indoor positioning technology is currently increasing in various industries. Although positioning methods using sensors and functions installed on smartphones have been proposed in previous studies, no definitive indoor positioning technology has yet been established. Therefore, this paper presents a positioning system that performs visible light communication using a rolling shutter sensor installed in smartphones and an optical diffusion filter that diffuses light in one direction. The system calculates the camera position from information obtained through communication and the LED position in the captured image. The performance of the positioning method using four LEDs was evaluated in both simulations and experiments. The obtained results suggest that the proposed positioning system achieved a positioning error of less than 100 mm. The proposed method can become a viable alternative to provide seamless transition from outdoor to indoor positioning using current technologies such as global navigation satellite systems.

We investigate the impact of voice imitation on rapport building in customer service in a virtual environment(VE). We simulated a VE store and conducted a within-subject experiment in three customer service scenarios with 16 participants. The imitation condition used a voice generated by a machine learning model to reproduce the participant’s linguistic content, with the voice identity set midway between the participant and the salesperson. In a group of men, voice imitation significantly improved their impression of salespeople. The findings of this study can be used to design interpersonal services in VE with the help of salesperson avatar voice design.

The opportunities to receive and provide services on virtual environment (VE) continue to increase. In this study, we focused on the voice in VE, and investigated the effects of whisper voice, which is used in intimate relationships, on interpersonal distance between salesperson and customer and the effective range of ventriloquism effect. The experimental results showed two results when the salesperson used whisper voice. The interpersonal distance between them was significantly smaller than that of the normal voice. The effective range of the ventriloquism effect was significantly larger on the front side and significantly smaller on the backside compared to normal voice.

A method of estimating location by acoustical signal and microphone array without the detection of direction-of-arrival is proposed. The proposed method consists of the following steps. First, acoustic beacons in the environment emit signals and the localizing target receives the signals with a microphone array. Next, the localizing target calculates the probability distribution of the location by a particle filter. The cross-correlation functions of the microphone array elements correspond to the location and beacon arrangement. Herein, the cross-correlation functions are used as a likelihood function by projecting them to the localizing state space. The localization result is calculated as the weighted sum of the particles based on their likelihoods. The proposed method is tested and evaluated in an indoor environment with four beacons. The result shows that the proposed method can achieve better localization than the previous method.

The people with visual impairment are facing the problem of the difficulty of reaching their desired destination. However, to have people who are with visual impairment updated with the necessary information about the location that they are traversing in order to secure safety and independent mobility, they need to depend on non-visual information to get the information they need.This paper proposes a system that automatically presents the sound image directly from arrival point without depending on the installation position of the sound source.This system works via presenting audible cues in the direction of the destination of the user without depending on the loudspeaker location. The success probability of direction guiding to the fixed destination for the proposed method was calculated and the results has revealed success probability of about 90%. As a result, this system presents the direction of the destination intuitively and easily by presenting the sound image of the guidance sound only for the person who needs information.

In this paper, signals for acoustic beacons with M sequence are evaluated with various parameters for self-localization of mobile robot. The effect of (i) baud rate, (ii) carrier frequency and (iii) order of M sequence on DOA estimation error and localization error are evaluated by computer simulation. As a result, localization is possible with same class or more precision compared to the result from sound beacon with three chirp signals within 5 kHz-18 kHz by choosing the appropriate parameters, which are (i)baud rate is more than around 8 kHz and (ii)carrier frequency is 10 kHz. Particularly, (i) baud rate and (ii) carrier frequency have influence on the localization error. However, the localization error do not change into even a further baud rate in this condition if baud rate is higher than carrier frequency. In this simulation, no influence is confirmed from (iii)order of M sequence. The result indicates that M sequence can be used as signal of acoustic beacons instead of chirp, which occupies frequency band.