Activity-Based Computing (ABC) has been proposed as an organisational structure for local desktop management and knowledge work. Knowledge work, however, typically occurs in partially overlapping subgroups and involves the use of multiple devices. We introduce co-Activity Manager, an ABC approach that (i) supports activity sharing for multiple collaborative contexts, (ii) includes collaborative tools into the activity abstraction and (iii) supports multiple devices by seamlessly integrated cloud support for documents and activity storage. Our 14 day field deployment in a multidisciplinary software development team showed that activity sharing is used as a starting point for long-term collaboration while integrated communication tools and cloud support are used extensively during the collaborative activities. The study also showed that activities are used in different ways ranging from project descriptions to to-do lists, thereby confirming that a document-driven activity roaming model seems to be a good match for collaborative knowledge work.

Interactive surfaces have great potential for co-located collaboration because of their ability to track multiple inputs simultaneously. However, the multi-user experience on these devices could be enriched significantly if touch points could be associated with a particular user. Existing approaches to user identification are intrusive, require users to stay in a fixed position, or suffer from poor accuracy. We present a non-intrusive, high-accuracy technique for mapping touches to their corresponding user in a collaborative environment. By mounting a high-resolution camera above the interactive surface, we are able to identify touches reliably without any extra instrumentation, and users are able to move around the surface at will. Our technique, which leverages the back of users' hands as identifiers, supports walk-up-and-use situations in which multiple people interact on a shared surface.

Complex 3D interaction in virtual environments may inhibit user interaction and cause frustration. Supporting adaptivity based on the detected user frustration can be considered as one promising solution to enhance user interaction. Our work proposes to provide adaptive assistance to users who are frustrated during their interac- tion with 3D user interfaces in virtual environments. The obtrusive- ness of physiological measurements to detect frustration inspired us to investigate the pressure patterns exerted on a 3D input de- vice for this purpose. The experiment presented in this paper has shown a great potential on utilizing the finger pressure measures as an alternative to physiological measures to indicate user frustration during interaction. Furthermore, the findings in this particular con- text showed that adaptation of haptic interaction was effective in increasing the user's performance and making users feel less frus- trated in performing their tasks in the 3D environment.

In this paper we present a conceptual reference framework – the iDiscover framework – to make informed decisions on integrating technology in a museum environment in order to enhance the visitor experience. Our framework presents four dimensions of context that have proven to be indispensible for situation the most appropriate solutions for a specific cultural heritage site: the degree of mobility, the degree of personalisation, the degree of interaction with the environment and the degree of social interactions. Three cases are described in which we succesfully used this reference framework for creating mobile guides that fit both with the context of use and with the needs of the cultural heritage institute.