Passengers in autonomous vehicles enjoy the comfort of being free from driving tasks, but they inevitably experience anxiety caused by autonomous vehicle stress (AVS). AVS encompasses vehicle behavior stress due to unpredictable acceleration, and external environmental stress due to potential collisions. Past research has explored approaches to improve passengers’ comfort through behavior control and information presentation. However, methods that utilize stressful vehicle behavior in Extended Reality (XR) entertainment to distract from AVS-related anxiety are limited. Hence, the goal of this study was to maximize passenger comfort in automated vehicles. To achieve this goal, we implemented an XR entertainment system that utilizes vehicle behavior and evaluated its effect on reducing anxiety. In this study, we proposed “Hype D-Live”, an XR live music system designed to reduce anxiety by providing multimodal visual, auditory, force, and vestibular stimuli using a hemispherical display and motion platform mounted on a vehicle. We developed system functions to adjust the force and vestibular senses according to the excitement level of the music and the direction of stressful acceleration and to reproduce moshing, a characteristic behavior at live music venues. However, we hypothesized that passengers might not fully enjoy the entertainment and could experience anxiety if the video content makes them aware of the external environment. Therefore, we conducted an experiment with a within-participant design, involving 24 participants (14 males and 10 females), comparing 3 types of video content for XR entertainment inside the autonomous vehicle: a real external environment, a virtual simulation of the external environment, and a virtual live music venue. The Wilcoxon signed rank test with the Bonferroni correction after the Friedman test revealed that, without the moshing function, the virtual live music venue video significantly enhanced enjoyment and reduced anxiety, compared to the real one.

One of the stress factors for passengers in an autonomous vehicle is the stress from vehicle behavior caused by unpredictable acceleration, deceleration, and route changes. Although there are researches on stress reduction methods using behavior control and information presentation to realize a comfortable autonomous vehicle, there are still few methods for stress reduction and dissipation through application to XR entertainment. In this work, we propose "Hype Dlive", a system that utilizes vehicle behavior as XR live music performance, and aims to improve passenger comfort by utilizing vehicle behavior as tactile and vestibular stimuli to generate a sense of presence and excitement.

In recent years, video traffic has rapidly increased, and reducing video traffic is an important issue for network providers. By caching video content at cache servers close to users, network providers can expect to reduce the video traffic in the networks. However, the storage capacity of cache servers is limited, so it is necessary to carefully select contents to be cached to effectively utilize the limited cache resources. In order to make effective use of cache resources, it is important to cache content based on the popularity dynamics of video contents. It is known that video contents have different popularity dynamics in each video category. For example, videos of movie and music categories tend to maintain view counts over long time, whereas the view counts of videos of news and sports categories rapidly decrease. In this paper, we propose a caching method that selects video content to be cached based on the popularity dynamics of video content in each category. To clarify the effectiveness of the proposed caching method, we evaluate the cache hit ratio of the proposed method by a trace-driven simulator using a measured request pattern of YouTube videos. We show that the proposed method improves the cache hit ratio compared with the LRU.