Affordances support interaction by suggesting actions, while anti-affordances discourage or complicate task execution. In this work, we focus on property-based affordances and anti-affordances arising from a device’s physical properties, such as form, texture, and volume. We investigate how the usability of a handheld device changes when the property-based affordance of its grip transitions into an anti-affordance through a shape change. In a workshop exploring the design space for such transitions, which we term ’Useful Uselessness,’ we gathered concept ideas for shape-changing grips that can complicate or interrupt a task. Implementing three representative examples allowed us to study these grips during an exemplary drilling task. Our results show that changes in grip property can be especially useful for task interruption. We found that task context matters, and that shape-change type and its property have to be carefully chosen. In summary, we show that dynamically adapted property-based affordances can be useful to interrupt tasks, while safety issues have to be kept in mind.

Humans can distinguish two short simultaneous touches on the forearm, called Two-Point Discrimination (2PD), starting at a distance of approximately 40 mm. However, similar insights are lacking for vibrotactile stimuli, which would be essential for designing ergonomic gesture wristbands. Thus, an oriented 2PD test was performed using vibrotactile actuators on the forearm placed around the wrist (transverse) and along the forearm (longitudinal). The results indicate that the orientation between two actuators cannot be robustly distinguished. Two simultaneous stimuli on the forearm can best be detected at 90 mm distance, with a success rate of up to 96% for transverse placement when the actuators are arranged around the wrist. In this case, the actuators are approximately placed opposite each other, looking at the wrist as a circle. Thus, an actuator arrangement around the wrist is most sufficient to distinguish between a single and two simultaneous vibrotactile stimuli.

We use simple stickers on a wooden board to create ubiquitous touch interaction.Resonant frequencies make the board vibrate, creating tactile feedback when touching the stickers.In an experiment, we used stickers of three sizes to create Resonant Sticker Buttons and varied the delay of the feedback.Both size and feedback delay influenced the perceived weight of the buttons.While higher latencies result in a heavier perceived button, larger button sizes result in lighter perceived buttons and perceived feedback strength, and vice versa.Our findings suggest that touch interfaces with buttons of varying sizes, weights, and vibration strengths can be created on everyday surfaces, such as tables, by simply using stickers and speakers.

ICU Cockpit: a secure, fast, and scalable platform for collecting multimodal waveform data, online and historical data visualization, and online validation of algorithms in the intensive care unit. We present a network of software services that continuously stream waveforms from ICU beds to databases and a web-based user interface. Machine learning algorithms process the data streams and send outputs to the user interface. The architecture and capabilities of the platform are described. Since 2016, the platform has processed over 89 billion data points (N = 979 patients) from 200 signals (0.5-500 Hz) and laboratory analyses (once a day). We present an infrastructure-based framework for deploying and validating algorithms for critical care. The ICU Cockpit is a Big Data platform for critical care medicine, especially for multimodal waveform data. Uniquely, it allows algorithms to seamlessly integrate into the live data stream to produce clinical decision support and predictions in clinical practice.