Abstract not found

This paper describes an approach to writing requirements specifications for processcontrol systems, a specification language that supports this approach, and an example application of the approach and the language on an industrial aircraft collision avoidance system (TCAS II). The example specification demonstrates (1) the practicality of writing a formal requirements specification for a complex, process-control system and (2) the feasibility of building a formal model of a system using a specification language that is readable and reviewable by applications experts who are not computer scientists or mathematicians. Some lessons learned in the process of this work, which are applicable both to forward and reverse engineering, are also presented.

Abstract not found

This paper explores an alternative account, which relies on the notion of graphical implicature. Whether or not the current account is useful has broader significance, because if it is useful, it helps supply the first premise for the following argument: (i) there are certain parallels between pragmatic phenomena in natural language (NL) and graphical representation; (ii) formal techniques have been developed for modelling some of the NL phenomena; and thus (iii) once the graphical data are better-understood, we may be able to treat them with formal techniques from NL pragmatics. The paper has the following structure. First, we introduce the phenomena discussed by Petre and Green, and summarise their account. Then we introduce some key concepts from linguistic pragmatics, focussing on Grice's [1975] theory of implicature. We then indicate how Grice's ideas have been applied in the graphical domain, by Marks and Reiter [1990]. Finally, we show how the ideas apply to Petre and Green's observations, and relate the two accounts. 2 Network diagrams

Visual programming languages aim to broaden the use of diagrams within the software industry, to the extent that they are integrated into the programming language itself. As a result, they provide an ideal opportunity to study the benefits of diagrams as an external representation during problem solving: not only is programming a challenging problem-solving activity, but the effect of diagram usage can be directly assessed by comparing performance while using a visual programming language to performance with a standard textual language. There have been several misconceptions amongst visual language researchers regarding the role of diagrams in software design, but these are being addressed by empirical studies and by new theories of notation design derived from studies of visual programming. Based on this research, the authors are able to recommend several new directions for research into thinking with diagrams. Keywords: diagrams, diagrammatic reasoning, visual programming, ...

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...

End-users must write programs to control many different kinds of applications. Examples include multimedia authoring, controlling robots, defining manufacturing processes, setting up simulations, programming agents, scripting, etc. The languages used today for these tasks are usually difficult to learn and are based on professional programming languages. This is in spite of years of research highlighting the problems with these languages for novice programmers. The Natural Programming Project is developing general principles, methods, and programming language designs that will significantly reduce the amount of learning and effort needed to write programs for people who are not professional programmers. These principles are based on a thorough analysis of previous empirical studies of programmers, as well as new studies designed to discover the most natural programming paradigms. Our proposed research is to extend these results, and apply them to different domains. The result will be n...

Many different methods have been used to specify user interfaces: algebraic specification, grammars, task description languages, transition diagrams with and without extensions, rule-based systems, and by demonstration. However, none of these methods has been widely adopted. Current user interfaces are still built by writing a program, perhaps with the aid of a UIMS. There are two principal reasons for this. First, specification languages are difficult to use. Reading a specification and understanding its exact meaning is very difficult. Writing a correct specification is even more difficult. Second, most specification languages are not executable. This means that after the user interface programmer makes the effort to write a specification, the user interface must still be coded. As a consequence, most programmers have little incentive to do a specification. A pilot study into the comprehensibility of specifications is described. The results of this study suggest that user interface s...

This dissertation explores the concepts behind creating useful visualizations for the analysis and understanding of simulation environments. We define parameters for determining usefulness of visualizations, describe a methodology of visualization creation, and use this methodology to create a computerized automatic visualization generation system for an urban planning simulation system. The effective use of visualizations can lessen the burden of data retrieval and allows analysts to focus on information synthesis. Our visualization system allows users to specify a goal or task, and then the system designs visual displays that help users perform their tasks and achieve their goals. Our aim is to allow users to focus on their tasks rather than worry about the specifics of effective information presentation.

In this paper Green's (1989) notion of "cognitive dimensions" is used to consider the properties of notations and media for sketching. First, a cultural-cognitive approach to HCI research is briefly outlined which draws on some ideas from "distributed cognition" and Russian psychology. Rather than focussing on the cognitive aspects of an activity or the social aspects (as do cognitive psychology and ethnography, respectively) this approach attempts to describe the artifacts used in an activity in a cognitively and socially relevant way. It is argued that such an approach requires a framework within which to analyse external representations, and that Green's "cognitive dimensions" provide such a framework. The cognitive dimensions framework is described and then used to interpret a study of collaborative idea sketching which used interviewing, observational methods and a questionnaire survey of 128 academics. This analysis resulted in a cohesive and comprehensive characterisati...