Carol Britton

Cognitive Dimensions of Notations: Design Tools for Cognitive Technology

The Cognitive Dimensions of Notations framework has been created to assist the designers of notational systems and information artifacts to evaluate their designs with respect to the impact that they will have on the users of those designs. The framework emphasizes the design choices available to such designers, including characterization of the users activity, and the inevitable tradeoffs that will occur between potential design options. The resuliing framework has been under development for over 10 years, and now has an active community of researchers devoted to it. This paper first introduces Cognitive Dimensions. It then summarizes the current activity, especially the results of a one-day workshop devoted to Cognitive Dimensions in December 2000, and reviews the ways in which it applies to the field of Cognitive Technology.

Using an expert panel to validate a requirements process improvement model

In this paper we present components of a newly developed software process improvement model that aims to represent key practices in requirements engineering (RE). Our model is developed in response to practitioner needs highlighted in our empirical work with UK software development companies. We have now reached the stage in model development where we need some independent feedback as to how well our model meets our objectives. We perform this validation through involving a group of software process improvement and RE experts in examining our RE model components and completing a detailed questionnaire. A major part of this paper is devoted to explaining our validation methodology. There is very little in the literature that directly relates to how process models have been validated, therefore providing this transparency will benefit both the research community and practitioners. The validation methodology and the model itself contribute towards a better understanding of modelling RE processes.

A survey of current practice in the development of multimedia systems

Abstract A better understanding of the distinguishing characteristics of different forms of system development is vital if we are to tailor recommendations regarding good practice to the specific needs of particular projects. This paper presents the findings of a survey carried out in order to ascertain the current state of practice amongst developers of multimedia systems. The survey involved conducting structured interviews with professional multimedia developers from seven different organizations, and analysing feedback from postal questionnaires completed by developers working in 16 further organizations. The findings are used here to identify some of the features which distinguish multimedia system development projects from more conventional software developments.

The Use of a Co-operative Student Model of Learner Characteristics to Configure a Multimedia Application

This paper describes an investigation into the ways in which learning using a multimedia application can be supported and enhanced by means of a simple co-operative student model of learner characteristics. This paper reports the design, implementation and evaluation of an individually configurable multimedia learning application, based upon such a model.A multimedia learning application was developed that presented information differentially based upon the individual characteristics of learners, held in the student model. The characteristics employed in the model were language level, cognitive style, task and question levels, and help level. Small groups of learners followed the multimedia course in learning centres located in colleges in the UK. A Grounded Theory study was carried out in order to understand the many and complex interactions that took place between learners, tutors and the learning environment.Stages in the Grounded Theory method are described and some qualitative data is presented. It was possible to conclude from these, that the quality of learning for individuals was improved by the use of the co-operative student model. Quantitative data is presented to support this view and where possible, to relate performance on the multimedia learning application to the student model configuration.

Specifying multiple time granularities in interactive systems

Time plays an important role in interactive systems, but can be difficult to specify, particularly where temporal properties exist at several different time granularities. The relationship between different time granularities is complex and translation between them can be difficult. In this paper, we discuss this relationship and highlight the way in which translation between different time granularities within a single specification may have important consequences for system behaviour. Using the notation TRIO≠, we provide examples from an interactive case study of the ways in which system behaviour may be influenced, and illustrate some of the potential difficulties which arise in the specification of temporal properties such as pace and regularity.

Technology transfer for reuse: a management model and process improvement framework

Increasingly, software organisations are looking towards large-scale systematic reuse as a way of improving productivity, raising quality and reducing delivery timescales. We discuss technology transfer for reuse at the RE (requirements engineering) level. We first examine the state-of-the-art in terms of the approaches to RE reuse currently suggested in the literature. We then discuss factors in the reuse technology transfer process, and argue that most of the existing work focuses on one particular strand of technology transfer namely that of the technical reuse process. We highlight the need to address the reuse management process, and propose a generic process model for RE reuse called ORM (Operational Reuse Model). We also discuss evaluation issues related to reuse technology transfer, and conclude with lessons and observations on making reuse a normal part of RE practice.

An empirical study of user preference and performance with UML diagrams

Elicitation and validation of user requirements depend, to a large extent, on the effectiveness of the tools and techniques used as a vehicle for discussion between developers and users during the requirements process. This effectiveness may, in turn, be influenced by user preference for a particular approach or requirements technique. This paper describes a study that was carried out to investigate the relationship between user preference for sequence or collaboration diagrams in UML, with their accuracy in understanding information contained in the diagrams. Results showed that user preference for one of the two diagram types before carrying out the task was not reflected in improved performance with that type of diagram compared with the other. However, after carrying out the task, user statements about which type of diagram they preferred working with were matched by improved performance with that type of diagram.

Early elicitation and definition of requirements for an interactive multimedia information system

The literature on requirements engineering contains little in the way of either theoretical guidance or empirical case studies relating to the specification of requirements for interactive multimedia information systems. This paper describes some of the special difficulties currently encountered in the early stages of developing such systems. It then presents a description of the methods and tools used in the early stages of the MARS project, whose aim is to develop an interactive multimedia system for use in school-based health education and anti-smoking campaigns directed at children aged 9-10. The paper ends with a discussion of lessons learnt with respect to some current issues in requirements engineering, and considers the extent to which the particular problems identified earlier in the paper were addressed by the methods and tools used in the MARS project. We conclude that further work in this area is badly needed, so that better guidance on the specification of requirements for interactive multimedia information systems can be given in future.

Evaluating the Intelligibility of Diagrammatic Languages Used in the Specification of Software

This paper presents an approach to evaluating the intelligibility of diagrammatic languages used in the specification of software. Research suggests that specification languages can be assessed in terms of properties that influence the intelligibility of representations produced using the languages. The paper describes the properties identified and highlights three in particular that have been shown to influence the intelligibility of representations: motivation of symbols in the language; the extent to which the language allows exploitation of human visual perception; and the amount of structure inherent in the language. The paper argues that the first two of these properties are not present to any great extent in diagrammatic languages used in software specification. In order to enhance the intelligibility of software specifications, we suggest that more attention should be paid to ways in which these languages can exploit the amount of structure inherent in the language.

An empirical study of factors that affect user performance when using UML interaction diagrams

During the requirements process it is of key importance that all representations used are clearly understood by those who must use them. Therefore it is essential to ensure that those representations are presented as effectively as possible. The research reported in this paper relates to an empirical study carried out to investigate factors which might affect user performance when using UML interaction diagrams. Several variables were investigated in the study; these were identified from the related literature and earlier research by us as being important in understanding interaction diagrams. The independent variables investigated in the study were diagram type, user pre-test and post-test preference, individuals cognitive style, text direction, scenario type and question type. Time taken to formulate the correct answer was the dependent variable used as the measure of performance. Statistical analysis of data showed significant differences for several variables, including diagram type, preference, and scenario type (p<0.05).