Complex design problems require more knowledge than any single person possesses because the knowledge relevant to a problem is usually distributed among stakeholders. Bringing different and often controversial points of view together to create a shared understanding among these stakeholders can lead to new insights, new ideas, and new artifacts. New media that allow owners of problems to contribute to framing and resolving complex design problems can extend the power of the individual human mind. Based on our past work and study of other approaches, systems, and collaborative and participatory processes, this article identifies challenges we see as the limiting factors for future collaborative human-computer systems. The Envisionment and Discovery Collaboratory (EDC) is introduced as an integrated physical and computational environment addressing some of these challenges. The vision behind the EDC shifts future development away from the computer as the focal point, toward an emphasis that tries to improve our understanding of the human, social, and cultural system that creates the context for use. This work is based on new conceptual principles that include creating shared understanding among various stakeholders, contextualizing information to the task at hand, and creating objects to think with in collaborative design activities.

This paper discusses the use of gesture and non-speech audio as ways to improve the user interface of a mobile music player. Their key advantages mean that users could use a player without having to look at its controls when on the move. Two very different evaluations of the player took place: one based on a standard usability experiment (comparing the new player to a standard design) and the other a video analysis of the player in use. Both of these showed significant usability improvements for the gesture/audiobased interface over a standard visual/pen-based display. The similarities and differences in the results produced by the two studies are discussed.

Cultures deal with their environments by adapting to them and simultaneously changing them. This is particularly true for technological cultures, such as the dynamic culture of computer users. To date, the ability to change computing environments in non-trivial ways has been dependent upon the skill of programming. Because this skill has been hard to acquire, most computer users must adapt to computing environments created by a small number of programmers. In response to the scarcity of programming ability, the computer science community has concentrated on producing general-purpose tools that cover wide spectrums of applications. As a result, contemporary programming languages largely ignore the intricacies arising from complex interactions between different people solving concrete problems in specific domains. This dissertation describes Agentsheets, a substrate for building domain-oriented, visual, dynamic programming environments that do not require traditional programming skills. It discusses how Agentsheets supports the relationship among people, tools, and problems in the context of four central themes: (1) Agentsheets features a versatile construction paradigm to build dynamic, visual environments for a wide range of problem domains such as art, artificial life, distributed artificial intelligence, education, environmental design, and

or implied, of those organizations or of the United States government.

This paper clarifies the motivation and principles underlying the subjunctive interface concept, describes implementation work that illustrates the approach, and outlines directions for further pursuit of this research.

In this paper the interaction between users and the interactive theorem prover HOL is investigated from a human-computer interaction perspective. First, we outline three possible views of interaction, and give a brief survey of some current interfaces and how they may be described in terms of these views. Second, we describe and present the results of an empirical study of intermediate and expert HOL users. The results are analysed for evidence in support of the proposed view of proof activity in HOL. We believe that this approach provides a principled basis for the assessment and design of interfaces to theorem provers.

Modern computer systems routinely present information to the user as a combination of text and diagrammatic images, described as "graphical user interfaces". Practitioners and researchers in Human-Computer Interaction (HCI) generally believe that the value of these diagrammatic representations is derived from metaphorical reasoning; they communicate abstract information by depicting a physical situation from which the abstractions can be inferred. This assumption has been prevalent in HCI research for over 20 years, but has seldom been tested experimentally. This thesis analyses the reasons why diagrams are believed to assist with abstract reasoning. It then presents the results of a series of experiments testing the contribution of metaphor to comprehension, problem solving, explanation and memory tasks carried out using a range of different diagrams. The results indicate that explicit metaphors provide surprisingly little benefit for cognitive tasks using diagrams as an external re...

Domain-oriented systems offer many potential benefits for end-users such as more intuitive interfaces, better task support, and knowledge-based assistance. A key challenge for system developers constructing domain-oriented systems is determining what the current domain is and what the future domain should be; i.e. what entities should the system embody and how should they be represented. Determining an appropriate domain model is challenging because domains are not static entities that objectively exist, but instead they are dynamic entities that are constructed over time by a community of practice. New software development models and new computational tools are needed that support these communities to create initial models of the domain and to evolve these models over time to meet changing needs and practices. We describe a specific software development model and computational tools that enable domain practitioners to participate in domain construction processes. KEYWORDS: software d...

Previous research suggests that graphical metaphor should increase the usability of visual programming languages (VPLs) by providing an instructional aid when learning to use the language. This paper describes three experiments which manipulated the degree of metaphor in VPLs. In the first, an implicit pictorial metaphor was added to a dataflow language, while in the second and third an explicit explanatory metaphor was provided for diagrams showing computational concepts. In both cases, the performance of novices was compared to that of expert programmers, in order to judge the improvement in usability that might result from this instructional device. The resulting benefits of metaphor were smaller than expected, especially relative to the advantage of experience. This suggests that metaphor may not be an essential component in the usability of VPLs.

Complex design problems require more knowledge than any single person possesses because the knowledge relevant to a problem is usually distributed among stakeholders. Bringing different and often controversial points of view together to create a shared understanding among these stakeholders can lead to new insights, new ideas, and new artifacts. New media that allow owners of problems to contribute to framing and resolving complex design problems can extend the power of the individual human mind. Based on our past work and study of other approaches, systems, and collaborative and participatory processes, this paper identifies challenges we see as the limiting factors for future collaborative humancomputer systems. The Envisionment and Discovery Collaboratory (EDC) is introduced as an integrated physical and computational environment addressing some of these challenges. The vision behind the EDC shifts future development away from the computer as the focal point, toward an emphasis that tries to improve our understanding of the human, social, and cultural system that creates the context for use. This work is based on new conceptual principles that include creating shared understanding among various stakeholders, contextualizing information to the task at hand, and creating objects-to-think-with in collaborative design activities. Although the EDC framework is applicable to