We studied the memorability of free-form gesture sets for invoking actions. We compared three types of gesture sets: user-defined gesture sets, gesture sets designed by the authors, and random gesture sets in three studies with 33 participants in total. We found that user-defined gestures are easier to remember, both immediately after creation and on the next day (up to a 24% difference in recall rate compared to pre-designed gestures). We also discovered that the differences between gesture sets are mostly due to association errors (rather than gesture form errors), that participants prefer user-defined sets, and that they think user-defined gestures take less time to learn. Finally, we contribute a qualitative analysis of the tradeoffs involved in gesture type selection and share our data and a video corpus of 66 gestures for replicability and further analysis.

Runtime reconfigurable component models provide several attractions with regard to the management of wireless sensor network (WSN) applications operating in dynamic environments and under evolving application requirements. One such attraction is the runtime discovery of suitable components for reuse in changing application compositions. Syntactic interface typing, provided by contemporary component models, however only supports exact interface matching. This causes limited reuse of components and complicates management of WSN applications. We argue that more flexibility is required to efficiently manage the complex, large-scale and dynamic WSN deployments of the future. In this paper, we describe the addition of semantic service descriptions to component interfaces to support compatibility and subtype testing. This allows rich discovery and reuse of third-party functionality and reasoning at the level of equivalent service types. We report on the incorporation of these semantic interface definitions in the Loosely Coupled Component Infrastructure (LooCI). Evaluation thereof shows that the scheme imposes minimal computational and memory overhead, while significantly reducing the complexity and cost of reconfiguration.