Reasoning from a schema and from an analog in software code reuse

The activity of design involves the decomposition of problems into subproblems and the development and evaluation of solutions. In many cases, solution development is not done from scratch. Designers often evoke and adapt solutions developed in the past. These solutions may come from an internal source, i.e. the memory of the designers, and/or from an external source. The goal of this paper is to analyse the characteristics of the cognitive mechanisms, the knowledge and the representations involved in the code reuse activity performed by experienced programmers. More generally, the focus is the control structure of the reuse activity. Data collected in an experiment in which programmers had to design programs are analyzed. Two code reuse situations are distinguished depending on whether or not the processes involved in reuse start before the elaboration of what acts as a source-solution. Our analysis highlights the use of reasoning from a schema and from an analog in the code reuse activity

Representing the user: a sociological study of the discourse of human computer interaction

The discipline of Human Computer Interaction (HCI) was established in the early 1980's on the foundations of cognitive psychology, computer science and ergonomics. In recent years however, claims have been made for the relevance of forms of sociology to this avowedly multidisciplinary field, and a number of sociologists have attempted to contribute to the general enterprise of developing a deeper understanding of the computer user and thereby informing, and improving, software design. This thesis is, in one sense, a continuation of this emerging body of work. However, my contention is that little, if any, critical attention has been given within this work to questions that would seem to be of fundamental importance to attempts at collaboration between disciplines: how is the disciplinary organization of knowledge to be understood, and more specifically, can HCI be adequately described in the simple pluralist terms in which it tends to characterise itself? The primary focus then is on the discipline of HCI. Utilising a theoretical model which considers disciplines as distinctive discourses which constitute their own domains of objects, I analyse the discourse and practice of HCI in order to explicate some of its underlying premises and assumptions, and to argue that it has, unavoidably, set many of the parameters within which contributing disciplines must operate. Texts, audio and video tapes, and ethnographic observation of instances of HCI practice form the empirical basis of the thesis. In addition, an analysis of some recorded human-computer interactions, which like the study as a whole, exemplifies an approach that differs from the prevailing sociological models within the field, is used to support the argument

Distributed cognition and computer supported collaborative design: The organisation of work in construction engineering

This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.The intellectual contribution of this thesis lies within the area of computer supported co-operative work (CSCW), and more specifically, computer supported co-operative design (CSCD). CSCW is concerned with the development of information systems and technological support for multi-participant work activities. Research into CSCW seeks to understand how people and organisations interact with one another, and to integrate this understanding with the development of computer based tools to support real world settings. Much of the technology developed to support the work of designers has been developed to aid individuals working alone, with tools like computer aided drafting (CAD), scheduling, and database software. The growth of interest in ‘groupware’ has led many technology developers to adapt these design tools for use in group situations. However, joint activities are different from those performed alone, and organisational structures can both interfere with, and supplement co-operative work practices in a way that the current technologies cannot provide support for. To develop effective group design tools, we need to understand more about collaborative processes in design. This thesis draws from the theoretical underpinning of cognitive science and the methods of anthropology and sociology, in an interdisciplinary study of design performance in the construction industry. Fieldwork is used as a method of qualitative data collection and this is examined within the analytic framework of distributed cognition. The results of this analysis provide a useful and usable description of the work of design that technology developers can use to support collaborative design work. In line with the methods of distributed cognition, the activities observed in the workplace studies are examined in terms of their processes and representations. The resources that were available to the design participants are made explicit, as are their situation-specific work patterns. Two case studies of design are examined. The first of these describes design work in a civil engineering project, which involves a number of different design activities. The second describes the work of consulting engineers in building design, focusing on a more limited design role, which is used to back up and supplement areas of the first study that were understood to be particularly relevant. The findings of the study demonstrate how design processes operate simultaneously at personal, organisational and inter-organisational levels. The distinction between the formal, organisational procedures, and the informal, social processes that compliment them is examined to show how these are interrelated in the performance of the design task and their importance to the mechanisms used to co-ordinate actions. The findings of the study have implications for the development of novel technologies to augment the engineering design process, and have already been used in the development of assistive design technologies. The thesis demonstrates that the framework of distributed cognition can be used in the analysis of cognition within a setting, involving multiple individuals, in concert with 'natural' and 'artificial' artefacts. The thesis makes clear a number of processes in design that can only be examined from a perspective which includes the social dimensions of work. The methods of study focus on the resources in collaborative activities, whilst the analysis, structured in terms of the representations and processes of collaborative activity, shows that the method can be used effectively in the development of CSCW and CSCD technologies

Explanation in information systems: A design rationale approach.

This dissertation investigates the relationship between the information systems (IS) development context, and the context in which such systems are used. Misunderstandings and ambiguities emerge in the space between these contexts and often result in construction of systems that fail to meet the requirements and expectations of their intended users. This study explores this problem using an approach derived from three largely separate and distinct fields: explanation facilities in information systems, theories of explanation, and design rationale. Explanation facilities are typically included in knowledge-based information systems, where their purpose is to provide system users with the underlying reasons for why the system reaches a particular conclusion or makes a particular recommendation. Prior research suggests that the presence of an explanation facility leads to increased acceptance of these conclusions and recommendations, therefore enhancing system usability. Theory of explanation is a field of study in which philosophers attempt to describe the unique nature of explanation and to identify criteria for explanation evaluation. Design rationale research is concerned with the capture, representation, and use of the deep domain and artefact knowledge that emerges from the design process. The design rationale approach goes beyond specification and suggests that to understand a system requires knowledge of the arguments that led to its realisation. This study proposes a model of IS explanation structure and content derived from formal theories of explanation with a method for obtaining this content based on design rationale. The study has four goals: to derive a theory of explanation specific to the domain of information systems; to examine this definition empirically through a study involving IS development and management professionals; to investigate in a case study whether the information needed to populate the explanation model can be captured using design rationale techniques; and construction of prototype software to deliver explanations per the proposed framework

User modelling for evaluation of direct manipulation interfaces

This thesis applies models of user action to usability evaluation of direct manipulation interfaces. In particular, the utility of a Model of Action for assisting novice evaluators in usability tests is investigated. An initial model of user action is proposed, based on the theory of action proposed by Norman (1986). This model includes a description of knowledge sources used in interaction, error types and user responses to errors. The model is used to interpret data on user behaviour and errors in an empirical study of MacDraw I. This study used the Protocol Analysis technique proposed by Ericsson and Simon (1984). Protocol evidence shows that the search and specification stages of user action could usefully be treated as separate in terms of user knowledge recruitment and the nature of system support. The Model of Action is then expanded and modified to account for the empirical findings. The new model distinguishes knowledge-based, rule-based and skill-based processing in Direct Manipulation (DM) interaction, using the distinction drawn by Rasmussen (1986). These processing levels are explicitly linked to types of presentation technique and categories of user error. This is developed into a technique for determining system causes of usability problems. A set of mental dialogue tokens (roles) are developed to assist novice evaluators in the interpretation of error causes. Roles are linked to types of user error in the cycle of action in a diagnostic model. This model forms the basis of a budget method for use by novice evaluators, named Model Mismatch Analysis (MMA). These developments are tested by a two-tier study of user performance on Microsoft Word. The empirical evidence validated the taxonomy of errors, and tests the utility of five retrospective data analysis techniques. A study of novice evaluator performance is reported, comparing the MMA method to the Usability Checklist proposed by Ravden and Johnson (1989). The MMA method is shown to be the more efficient approach. To summarise, models of Direct Manipulation action are shown to assist novice evaluators both in the diagnosis of usability problems, and the selection of remedies