Pressure-induced dramatic changes in organic-inorganic halide perovskites.

Organic-inorganic halide perovskites have emerged as a promising family of functional materials for advanced photovoltaic and optoelectronic applications with high performances and low costs. Various chemical methods and processing approaches have been employed to modify the compositions, structures, morphologies, and electronic properties of hybrid perovskites. However, challenges still remain in terms of their stability, the use of environmentally unfriendly chemicals, and the lack of an insightful understanding into structure-property relationships. Alternatively, pressure, a fundamental thermodynamic parameter that can significantly alter the atomic and electronic structures of functional materials, has been widely utilized to further our understanding of structure-property relationships, and also to enable emergent or enhanced properties of given materials. In this perspective, we describe the recent progress of high-pressure research on hybrid perovskites, particularly regarding pressure-induced novel phenomena and pressure-enhanced properties. We discuss the effect of pressure on structures and properties, their relationships and the underlying mechanisms. Finally, we give an outlook on future research avenues in which high pressure and related alternative methods such as chemical tailoring and interfacial engineering may lead to novel hybrid perovskites uniquely suited for high-performance energy applications

VirusBoxing: A HIIT-based VR boxing game

Physical activity or exercise can improve people's health and reduce their risk of developing several diseases; most importantly, regular activity can improve the quality of life. However, lack of time is one of the major barriers for people doing exercise. High-intensity interval training (HIIT) can reduce the time required for a healthy exercise regime but also bring similar benefits of regular exercise. We present a boxing-based VR exergame called VirusBoxing to promote physical activity for players. VirusBoxing provides players with a platform for HIIT and empowers them with additional abilities to jab a distant object without the need to aim at it precisely. In this paper, we discuss how we adapted the HIIT protocol and gameplay features to empower players in a VR exergame to give players an efficient, effective, and enjoyable exercise experience.Comment: Corresponding author: [email protected]

Motion-based Interaction for Head-Mounted Displays

Recent advances in affordable sensing technologies have enabled motion-based interaction (MbI) for head-mounted displays (HMDs). Unlike traditional input devices like the mouse and keyboard, which often offer comparatively limited interaction possibilities (e.g., single-touch interaction), MbI does not have these constraints and is more natural because they reflect more closely people do things in real life. However, several issues exist in MbI for HMDs due to the technical limitations of the sensing and tracking devices, higher degrees of freedom afforded to users, and limited research in the area due to the rapid advancement of HMDs and tracking technologies. This thesis first outlines four core challenges in the design space of MbI for HMDs: (1) boundary awareness for hand-based interaction, (2) efficient hands-free head-based interface for HMDs, (3) efficient and feasible full-body interaction for general tasks with HMDs, and (4) accessible full-body interaction for applications in HMDs. Then, this thesis presents an investigation into the contributions of these challenges in MbI for HMDs. The first challenge is addressed by providing visual feedback during interaction tailored for such technologies. The second challenge is addressed by using a circular layout with a go-and-hit selection style for head-based interaction using text entry as the scenario. In addition, this thesis explores additional interaction mechanisms that leverage the affordances of these techniques, and in doing so, we propose directional full-body motions as an interaction approach to perform general tasks with HDMs as an example to address the third challenge. The last challenge is addressed by (1) exploring the differences between performing full-body interaction for HMDs and common displays (i.e., TV) and (2) providing a set of design guidelines that are specific to current and future HMDs. The results of this thesis show that: (1) visual methods for boundary awareness can help with mid-air hand-based interaction in HMDs; (2) head-based interaction and interfaces that take advantages of MbI, such as a circular interface, can be very efficient and low error hands-free input method for HMDs; (3) directional full-body interaction can be a feasible and efficient interaction approach for general tasks involving HMDs; (4) full-body interaction for applications in HMDs should be designed differently than for traditional displays. In addition to these results, this thesis provides a set of design recommendations and takeaway messages for MbI for HMDs

Mobile 5G Network Deployment Scheme on High-Speed Railway

The fifth-generation (5G) wireless communication has experienced an upsurge of interest for empowering vertical industries, due to its high data volume, extremely low latency, high reliability, and significant improvement in user experience. Specifically, deploying 5G on high-speed railway (HSR) is critical for the promotion of smart travelling such that passengers can connect to the Internet and utilize the on-board time to continue their usual activities. However, there remains a series of challenges in practical implementation, such as the serious Doppler shift caused by the high mobility, the carriage penetration loss especially in the high-frequency bands, frequent handovers, and economic issues. To address these challenges, we propose three schemes in this article to improve the coverage of 5G networks on the train. In particular, we provide a comprehensive description of each scheme in terms of their network architecture and service establishment procedures. Specifically, the mobile edge computing (MEC) is used as the key technology to provide low-latency services for on-board passengers. Moreover, these three schemes are compared among themselves regarding the quality-of-service, the scalability of service, and the related industry development status. Finally, we discuss various potential research directions and open issues in terms of deploying 5G networks on HSR

Who's Watching Me?: Exploring the Impact of Audience Familiarity on Player Performance, Experience, and Exertion in Virtual Reality Exergames

Familiarity with audiences plays a significant role in shaping individual performance and experience across various activities in everyday life. This study delves into the impact of familiarity with non-playable character (NPC) audiences on player performance and experience in virtual reality (VR) exergames. By manipulating of NPC appearance (face and body shape) and voice familiarity, we explored their effect on game performance, experience, and exertion. The findings reveal that familiar NPC audiences have a positive impact on performance, creating a more enjoyable gaming experience, and leading players to perceive less exertion. Moreover, individuals with higher levels of self-consciousness exhibit heightened sensitivity to the familiarity with NPC audiences. Our results shed light on the role of familiar NPC audiences in enhancing player experiences and provide insights for designing more engaging and personalized VR exergame environments.Comment: 10 pages, 5 figures, IEEE International Symposium on Mixed and Augmented Reality (ISMAR) 202

Design and Development of a Low-cost Device for Weight and Center of Gravity Simulation in Virtual Reality

With rapid advances in virtual reality (VR) technology, the use of haptics has become important to allow users to feel the physical properties of virtual objects. Current research has focused mainly on either weight variation or changing the center of gravity, which limits the simulation potential and may affect the feeling of immer- sion. This research explores the design and development of a device that can simulate both weight and center of gravity using low-cost components. Through an iterative design process and continuous testing with users, we arrived at a final prototype, FluidWeight, a device that can be attached to a typical VR handheld controller. FluidWeight uses fluid, which is transported from a central storage to a receptacle attached to the controller. A final experiment shows that users enjoyed using it because it could help increase the sense of realism in VR applications

Exploring the effect of the Group Size and Feedback of non-player character spectators in virtual reality exergames

Despite the widespread interest in leveraging non-player characters (NPCs) to enhance gameplay experiences, there is a gap in understanding of how NPC spectators (i.e., those virtual characters in the scene that watch users' actions) affect players. For instance, the impact of NPC spectators' presence and feedback on players' performance and experience has not been studied, especially in virtual reality (VR) exergames. This paper aims to fill this gap and reports two user studies that assess their effect on such games. Study 1 explored the impact of having NPC spectators present and their feedback available in a gesture-based VR exergame and found having NPC spectators and their feedback could improve players' game performance, experience, and exertion. Based on Study 1's results, we further explored two characteristics of the spectators—their group size (small/large) and their feedback (with/without). The results show that (1) a large spectator number is more helpful since it improves the overall game experience (higher competence, flow, immersion), increases AvgHR% (the average heart rate percentage divided by the maximum heart rate), and enhances performance (improved players' combo performance and increased gesture success rate for particular gesture); (2) spectator feedback is instrumental in improving players' performance (higher gesture success rates, more combos performed successfully, more monster's combos prevented), enhancing game experience (positive affect, competence, flow, and immersion), and reducing negative game experience, increasing exertion (AvgHR% and burned more calories). Based on the results, we derived two main design recommendations for VR exergames that could pave the way for improving gameplay performance and game experience, especially among young adults