The cognitive dimensions framework is a broad-brush evaluation technique for interactive devices and for non-interactive notations. It sets out a small vocabulary of terms designed to capture the cognitively-relevant aspects of structure, and shows how they can be traded off against each other. The purpose of this paper is to propose the framework as an evaluation technique for visual programming environments. We apply it to two commercially-available dataflow languages (with further examples from other systems) and conclude that it is effective and insightful; other HCI-based evaluation techniques focus on different aspects and would make good complements. Insofar as the examples we used are representative, current VPLs are successful in achieving a good `closeness of match', but designers need to consider the `viscosity' (resistance to local change) and the `secondary notation' (possibility of conveying extra meaning by choice of layout, colour, etc.).

The paper outlines an approach to CSCW systems design based on the concept of `coordination mechanisms.' The concept of coordination mechanisms has been developed as a generalization of phenomena described in empirical investigations of the use of artifacts for the purpose of coordinating cooperative activities in different work domains. On the basis of the evidence of this corpus of empirical studies, the paper outlines a theory of the use of artifacts for coordination purposes in cooperative work settings, derives a set of general requirements for computational coordination mechanisms, and sketches the architecture of Ariadne, a CSCW infrastructure for constructing and running such malleable and linkable computational coordination mechanisms.

In this paper we propose a theoretical framework of distributed representations and a methodology of representational analysis for the study of distributed cognitive tasksÑtasks that require the processing of information distributed across the internal mind and the external environment. The basic principle of distributed representations is that the representational system of a distributed cognitive task is a set of internal and external representations, which together represent the abstract structure of the task. The basic strategy of representational analysis is to decompose the representation of a hierarchical task into its component levels so that the representational properties at each level can be independently examined. The theoretical framework and the methodology are used to analyze the hierarchical structure of the Tower of Hanoi problem. Based on this analysis, four experiments are designed to examine the representational properties of the Tower of Hanoi. Finally, the nature of external representations is discussed.

This article proposes a theoretical framework for external representation based problem solving. The Tic-Tac-Toe and its isomorphs are used to illustrate the procedures of the framework as a methodology and test the predictions of the framework as a functional model. Experimental results show that the behavior in the Tic-Tac-Toe is determined by the directly available information in external and internal representations in terms of perceptual and cognitive biases, regardless of whether the biases are consistent with, inconsistent with, or irrelevant to the task. It is shown that external representations are not merely inputs and stimuli to the internal mind and that they have much more important functions than mere memory aids. A representational determinism is suggested--the form of a representation determines

this paper, I review the history of HCI as steps toward a science of design. My touchstone is Simon's (1969) provocative book he Sciences of the Artificial. The book pre-dates HCI, and many of its specific characterizations and claims about design are no longer authoritative (see Ehn, 1988). Nevertheless, two of Simon's themes echo through the history of HCI, and still provide guidance for charting its continuing development

Abstract. The received understanding of the status of formal organizational constructs in cooperative work is problematic. The paper shows that the empirical evidence is not as strong as we may have believed and that there is evidence from other studies that contradicts what we may have taken for granted for years. This indicates that the role of formal constructs is more differentiated than generally taken for granted. They not only serve as ‘maps ’ but also as ‘scripts’. Thanks to impressive CSCW systems such as TeamWork-Station [25], GroupDesk [16], wOrlds [15], and TeamRoom [33], to name but a few, it is by now widely accepted that computer artifacts can provide effective support for cooperative work by offering a ‘shared space ’ through which actors can interact directly, i.e., by means of generic competencies such as talking, gesturing, pointing, monitoring etc., without

This chapter discusses a core phenomenon for a theory of CSCL: building collaborative knowing. Rather than reviewing, one after another, various theories that are currently influential in the field of CSCL (and that are described in other chapters), a view of collaboration is outlined here that

This essay compares activity theory (AT) with distributed cognition theory (DCOG), asking what each can do for CSCW. It approaches this task by proposing that theories – when viewed as conceptual tools for making sense of a domain – have four important attributes: descriptive power; rhetorical power; inferential power; and application power. It observes that AT and DCOG are not so different: both emphasize cognition; both include the social and cultural context of cognition; both share a commitment to ethnographically collected data. Starting with a description of the distributed cognition approach, it uses an example of a DCOG analysis to ground a discussion of the strengths and weaknesses of AT and DCOG as an approach to issues in CSCW. Finally, the essay considers what theoretical work is being done by the attributes of the respective theories, and whether AT, DCOG, or any theory developed outside the context of group work, will work for CSCW.

This article shows how the concept of affordance in the user interface fits into a wellunderstood artificial intelligence (AI) model of acting in an environment. In this model AI planning research is used to interpret affordances in terms of the costs associated with the generation and execution of operators in a plan. We motivate our approach with a brief survey of the affordance literature and its connections to the planning literature, and then explore its implications through examples of common user interface mechanisms described in affordance terms. Despite its simplicity, our modeling approach ties together several different threads of practical and theoretical work on affordance into a single conceptual framework. Affordances in a planning representation 3 Contents 1 INTRODUCTION 4 2 PERSPECTIVES ON THE NATURE OF AFFORDANCES 5 3 AFFORDANCES IN PLANNING TERMS 8 4 GENERIC USER INTERFACE AFFORDANCES 13 4.1 Programmable User Models for Affordance Evaluation . . . . . . . . . . ....

Workflow management systems are considered a hot technology. Nevertheless, up to now they have not had the diffusion other packages such as productivity tools, e-mail systems and groupware platforms have. We believe that this fact is due to the many limitations of current workflow technology (weak support for changes; complex exception handling mechanisms; limited openness to and integrability with other system components; ...) and that radically new workflow management systems should be designed and developed in order to offer adequate products to the market. In this paper we outline the main innovative features of the workflow management component of the MILANO system making it highly flexible and adaptable. A particular attention is paid to its modelling framework which is based on a class of net systems well supported by efficient algorithms and to the services it offers to both workflow designers and actors. The most relevant aspects of the MILANO workflow management system are also illustrated through a realistic example.