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.

Model-driven development of user interfaces has become increasingly powerful in recent years. Unfortunately, model-driven approaches have the inherent limitation that they cannot handle the informal nature of some of the artifacts used in truly multidisciplinary user interface development such as storyboards, sketches, scenarios and personas. In this chapter, we present an approach and tool support for multidisciplinary user interface development bridging informal and formal artifacts in the design and development process. Key features of the approach are the usage of annotated storyboards, which can be connected to other models through an underlying meta-model, and cross-toolkit design support based on an abstract user interface model.

In model-based user interface development, models at different levels of abstraction are used. While ideas may initially only be expressed in more abstract models, modifications and improvements according to user's feedback will likely be made at the concrete level, which may lead to model inconsistencies that need to be fixed in every iteration. Transformations form the bridge between these models. Because one-to-one mappings between models cannot always be defined, these transformations are completely manual or they require manual post-treatment. We propose interactive but automatic transformations to address the mapping problem while still allowing designer's creativity. To manage consistency and semantic correctness within and between models and therefore to foster iterative development processes, we are combining these with techniques to track decisions and modifications and techniques of intra- and inter-model validation. Our approach has been implemented for abstract and concrete user interface models using Eclipse-based frameworks for model-driven engineering. Our approach and tool support is illustrated by a case study.

Despite the fact many proposals have been made for abstract user interface models it was not given a detailed context in which it should or could be used in a user-centered design process. This paper presents a clear role for the abstract user interface model in user-centered and model-based development, provides an overview of the stakeholders that may create and/or use abstract user interface models and presents a modular abstract user interface modeling language, CAP3, that makes relations with other models explicit and builds on the foundation of existing abstract user interface models. The proposed modeling notation is supported by a tool and applied to some case studies from literature and in some projects. It is also validated based on state-of-the-art knowledge on domain-specific modeling languages and visual notations and some case studies.

Despite the fact many proposals have been made for abstract user interface models it was not given a detailed context in which it should or could be used in a user-centered design process. This paper presents a clear role for the abstract user interface model in user-centered and model-based development, provides an overview of the stakeholders that may cre- ate and/or use abstract user interface models and presents a modular abstract user interface modeling language, CAP3, that makes relations with other models explicit and builds on the foundation of existing abstract user interface models. The proposed modeling notation is supported by a tool and applied to some case studies from literature and in some projects. It is also validated based on state-of-the-art knowledge on domain-specific modeling languages and visual notations and some case studies.