Widely-accepted sleep guidelines advise regular bedtimes and sleep hygiene. An individual's adherence is often viewed as a matter of self-regulation and anti-procrastination. We pose a question from a different perspective: What if it comes to a matter of one's social or professional duty that mandates irregular daily life, making it incompatible with the premise of standard guidelines? We propose SleepGuru, an individually actionable sleep planning system featuring one's real-life compatibility and extended forecast. Adopting theories on sleep physiology, SleepGuru builds a personalized predictor on the progression of the user's sleep pressure over a course of upcoming schedules and past activities sourced from her online calendar and wearable fitness tracker. Then, SleepGuru service provides individually actionable multi-day sleep schedules which respect the user's inevitable real-life irregularities while regulating her week-long sleep pressure. We elaborate on the underlying physiological principles and mathematical models, followed by 3-stage study and deployment. We develop a mobile user interface providing individual predictions and adjustability backed by cloud-side optimization. We deploy SleepGuru in-the-wild to 20 users for 8 weeks, where we found positive effects of SleepGuru in sleep quality, compliance rate, sleep efficiency, alertness, long-term followability, and so on.
Haptic feedback not only enhances immersion in virtual reality (VR) but also delivers experts’ haptic sensation tips in VR training, e.g., properly clamping a tenon and mortise joint or tightening a screw in the assembly of VR factory training, which could even improve the training performance. However, various and complicated manipulation is in different scenarios. Although haptic feedback of virtual objects’ shape, stiffness or resistive force in pressing or grasping is achieved by previous research, rotational resistive force when twisting or turning virtual objects is seldom discussed or explored, especially for a wearable device. Therefore, we propose a wearable device, ELAXO, to integrate continuous resistive force and continuous rotational resistive force with or without resilience in grasping and twisting, respectively. ELAXO is an exoskeleton with rings, mechanical brakes and elastic bands. The brakes achieve shape rendering and switch between with and without resilience modes for the resistive force. The detachable and rotatable rings and elastic bands render continuous resistive force in grasping and twisting. We conducted a just noticeable difference (JND) study to understand users’ distinguishability in the four conditions, resistive force and rotational resistive force with and without resilience, separately. A VR study was then performed to verify that the versatile resistive force feedback from ELAXO enhances the VR experiences.
When playing scales on the piano, playing all notes evenly is a basic technique to improve the quality of music. However, it is difficult for beginners to do this because they need to achieve appropriate muscle synergies of the forearm and shoulder muscles, i.e., pressing keys as well as sliding their hands sideways. In this paper, we propose a system using electrical muscle stimulation (EMS) to teach beginners how to improve their muscle synergies while playing scales. We focus on ``thumb-under'' method and assist with it by applying EMS to the deltoid muscle. We conducted a user study to investigate whether our EMS-based system can help beginners learn new muscle synergies in playing ascending scales. We divided the participants into two groups: an experimental group that practiced with EMS and a control group that practiced without EMS. The results showed that practicing with EMS was more effective in improving the evenness of scales than without EMS and that the muscle synergies changed after practicing.
Tickling is a type of sensation that is associated with laughter, smiling, or other similar reactions. Psychology research has shown that tickling and laughter can significantly relieve stress. Although several tickling artifacts have been suggested in prior work, limited knowledge is available if those artifacts could evoke laughter. In this article, we aim at filling this gap by designing and developing a novel foot-tickling mechanism that can evoke laughter. We first developed an actuator that can create tickling sensations along the sole of the foot utilising magnet-driven brushes. Then, we conducted two studies to identify the most ticklish locations of the foot’s sole and stimulation patterns that can evoke laughter. In a follow-up study with a new set of participants, we confirmed that the identified stimuli could evoke laughter. From the participants’ feedback, we derived several applications that such a simulation could be useful. Finally, we embedded our actuators into a flexible insole, demonstrating the potential of a wearable tickling insole.