Smartphone users' decisions about whether to attend to a notification after sensing it are under-researched. We therefore studied 33 Android users, and found that they speculated extensively about notifications' sources---i.e., which apps and which senders were responsible for them--- before attending to them. The participants' speculation about apps was both more common and more accurate than that about senders. They also were more likely to 1) perceive notifications as important, 2) attend to them, and 3) consider them beneficial if they speculated about them than if they did not or could not. Participants' speculations were based on the alert's inherent characteristics, context, and temporality. Inaccurate speculations were mainly caused by unclear signals, insufficient clues, and a multiplicity of possible sources. Ringer mode affected the accuracy of user speculation, but not its frequency or the frequency of attending to notifications.

360-degree video contains a full field of environmental content. However, browsing these videos, either on screens or through head-mounted displays (HMDs), users consume only a subset of the full field of view per a natural viewing experience. This causes a search problem when a region-of-interest (ROI) in a video is outside of the current field of view (FOV) on the screen, or users may search for non-existing ROIs. We propose Outside-In, a visualization technique which re-introduces off-screen regions-of-interest (ROIs) into the main screen as spatial picture-in-picture (PIP) previews. The geometry of the preview windows further encodes a ROI's relative location vis-à-vis the main screen view, allowing for effective navigation. In an 18-participant study, we compare Outside-In with traditional arrow-based guidance within three types of 360-degree video. Results show that Outside-In outperforms in regard to understanding spatial relationship, the storyline of the content and overall preference. Two applications are demonstrated for use with Outside-In in 360-degree video navigation with touchscreens, and live telepresence.

Online fitness videos make it possible and popular to do exercise at home. However, it is not easy to notice the details of motions by merely watching training videos. We propose a new type of motion guidance system that simulates the way that the human body moves as driven by muscle contractions. We have designed external artificial muscles on a sleeve to create a pulling sensation that can guide the forearm's pronation (internal rotation) and the forearm's supination (external rotation). The sleeve consists of stepper motors to provide pulling force, fishing lines and elastic bands to imitate muscle contraction to drive the forearm to rotate instinctively. We present two preliminary experiments. The first one shows that this system can effectively guide the forearm to rotate in the correct direction. The second one shows that users can be guided to the targeted angle by utilizing a tactile cue. We also report users' feedback through the experiments and provide design recommendations and directions for future research.