PriCal is an ambient calendar display that shows a user's schedule similar to a paper wall calendar. PriCal provides context-adaptive privacy to users by detecting present persons and adapting event visibility according to the user's privacy preferences. We present a detailed privacy impact assessment of our system, which provides insights on how to leverage context to enhance privacy without being intrusive. PriCal is based on a decentralized architecture and supports the detection of registered users as well as unknown persons. In a three-week deployment study with seven displays, ten participants used PriCal in their real work environment with their own digital calendars. Our results provide qualitative insights on the implications, acceptance, and utility of context-adaptive privacy in the context of a calendar display system, indicating that it is a viable approach to mitigate privacy implications in ubicomp applications.

Searching for misplaced keys, phones, or wallets is a common nuisance. Find My Stuff (FiMS) provides search support for physical objects inside furniture, on room level, and in multiple locations, e.g., home and office. Stuff tags make objects searchable while all other localization components are integrated into furniture. FiMS requires minimal configuration and automatically adapts to the user's furniture arrangement. Object search is supported with relative position cues, such as "phone is inside top drawer" or "the wallet is between couch and table," which do not require exact object localization. Functional evaluation of our prototype shows the approach's practicality with sufficient accuracy in realistic environments and low energy consumption. We also conducted two user studies, which showed that objects can be retrieved significantly faster with FiMS than manual search and that our relative position cues provide better support than map-based cues. Combined with audiovisual feedback, FiMS also outperforms spotlight-based cues.

Searching for lost keys, wallets or mobile phones is a common nuisance. Compared to digital information, search support for physical objects is very limited. We propose Find My Stuff (FiMS) as a search engine for physical objects. We built a fully functional Arduino-based prototype. FiMS offers the users a simple search interface to locate tagged physical items in different indoor environments. A hierarchical search process ensures energy efficient and effective searches. Instead of a fixed search infrastructure, the localization system is based on SmartFurniture equipped with RFID readers and ZigBee modules. Search results provide intuitive search cues based on relative positioning to support users in the physical retrieval of their lost objects. The system requires no manual calibration and is robust against rearrangement of SmartFurniture. Safety mechanisms prevent abuse of the system and protect user privacy.

The Multifunctional and Adaptive Meal Preparation Facility (MAMPF) is a versatile and adaptive kitchen system allowing even an inexperienced user to create ambitious dishes. On the hardware side, the system controls hotplates by regulating the temperature of heated regions to turn the attention to the food actually being heated instead of the hotplate. Furthermore, the user interaction with the computer system is adapted to the requirements in a kitchen. On the work flow side, MAMPF converts a recipe into a task tree which is used to guide the user through the cooking process. By knowing the recipe, based on a formal description specially developed for this system, the optimal sequence of actions can be calculated. The system is designed to support the user without limiting spontaneity or creativity and can - if necessary - be used just like any usual stove. Consequentially, the user always retains control over the system, all settings can be overwritten at any point, and the order of the tasks can be dynamically rearranged. In order to prove the correctness of this concept, a prototype has been implemented.