Figure 1: We propose foot-based user authentication for public displays. Users in front of a public display (e.g., ticket machine)(1) provide input using heel rotations (2) and heel taps (3), allowing for unobtrusive and hands-free authentication in public.

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The use of social Virtual Reality (VR) among children is increasing, but with it comes new forms of harassment that can be difficult for parents to monitor. To address this issue, we have developed "Big Buddy", a prototype AI-moderator that aims to safeguard children from potential harassment in social VR. We conducted a study in which 43 children (aged 8-16) participated in a simulated social VR classroom, with fictitious competitors disrupting their game. When Big Buddy intervened, the children reported feeling significantly less negative emotions and felt safer. This is the first study to empirically examine the use of an embodied AI-moderator in social VR from the perspective of children, and it provides important insights for designing AI-moderators in social VR. CCS CONCEPTS• Human-centered computing → Collaborative and social computing.

Children experience new forms of harassment in Social Virtual Reality (VR), often inaccessible to parental oversight. We aimed to understand how an artificial intelligent moderator safeguarding children from harassment in social VR is perceived by children and parents, by introducing "Big Buddy", a Wizard-of-Oz embodied AI-moderator. 43 children (aged 8-16) played a towerblock-construction game in a simulated Social VR classroom where fictitious competitors disrupted their game and, in experimental conditions where present, Big Buddy intervened. We measured children's perceptions after the disruptions, towards Big Buddy, and the moderation actions it took. Children felt significantly less sad and safer when Big Buddy suspended the saboteur. Parents (n=17) noted Big Buddy's usefulness and felt reassured but would remain in the supervision loop. We present the first empirical research of a VR-embodied AI-moderator with children's and parents' perspectives, and propose design directions for embodied AI-moderators in Social VR. CCS CONCEPTS• Human-centered computing → Empirical studies in collaborative and social computing.