This paper reports on the design and re-design of an Ontological Sketch Model. OSM is a representation and method of usability assessment that is based on descriptions of the device model and the user's conceptual model of that device. The ultimate aim of this work is to develop an approach that focuses attention on device and conceptual models, and that is usable, useful and widely available for use. We present the rationale for the design of the OSM. The initial design for the OSM was based on descriptions of the entities in the domain of application, actions that the user can perform, and relationships (such as "constrains" and "affects") between entities. A formative evaluation of the usefulness and usability of this design showed that the approach was promising, but also highlighted limitations of the representation. In particular, novice analysts had difficulty writing descriptions at an appropriate level of detail and understanding the meanings of some relationships. This led to...

We present a new visual programming language and environment that serves as a form of feedback and representation in a Programming by Demonstration system. The language differs from existing visual languages because it explicitly represents data objects and implicitly represents operations by changes in data objects. The system was designed to provide non-programmers with programming support for common, repetitive tasks and incorporates some principles of cognition to assist these users in learning to use it. With this in mind, we analyze the language and its editor along cognitive dimensions. The assessment provides insight into both strengths and weaknesses of the system, suggesting a number of design changes. This work supported by the National Science Foundation under grant number IRI-9020089. Additional support provided by the Hertz Foundation and the AAUW. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing t...

c discipline---namely, the study of Human-Computer Interaction. The interface designers are often primarily theorem-proving or formal methods experts; they seldom have extensive training in the principles of Human-Computer Interaction (HCI) as well. Their interfaces are therefore not designed with explicit use of insights from the established techniques of research into HCI. This is quickly evident from inspection of the literature. A paper such as [10], for example, will be intended to `explain how to add modern user interfaces to existing theorem provers' but will contain no references to the HCI literature, though it may cite software engineering papers. To take another example, the developers of the Mural system expended a great deal of effort on its user interface, the design of which they discuss in detail in the book on Mural [7]. Yet the bibliography of this book contains no references to mainstream HCI research (again, there are several software engineering re

We present a user-centred, task-oriented, comparative evaluation of two query-based document skimming tools. ProfileSkim bases within-document retrieval on computing a relevance profile for a document and query; FindSkim provides similar functionality to the web browser Find-command. A novel simulated work task was devised, where experiment participants are asked to identify (index) relevant pages of an electronic book, given subjects from the existing book index. This subject index provides the ground truth, against which the indexing results can be compared. Our major hypothesis was confirmed, namely ProfileSkim proved significantly more efficient than Find-Skim, as measured by time for task. Moreover, indexing task effectiveness, measured by typical IR measures, demonstrated that ProfileSkim was better than FindSkim in identifying relevant pages, although not significantly so. The experiments confirm the potential of relevance profiling to improve query-based document skimming, which should prove highly beneficial for users trying to identify relevant information within long documents.

Accident reports are the result of investigations into accidents that have occurred in safety critical systems. It has been suggested that accident reports can be both complex and difficult texts to understand resulting in problems of comprehension. Graphical notations have been suggested as a way to resolve these difficulties due to their concise and visual nature. However, there is no evidence in the literature to support these claims. This thesis

Ontological Sketch Modelling (OSM) is a novel approach to usability evaluation that uses entity analysis rather than detailed task analysis. Comparison of entity-based models of the domain as seen by the user and as supported by the device reveals misfits that cause usability problems; similarly, problems with the `system image' can be exposed. In this paper

The field of HCI is gradually achieving sound theoretical descriptions of the activities, context and cognition of computer system users. How do these research results get applied by the people who design new user interfaces? Although we have theoretical descriptions of the activities of system users, we have fewer descriptions of the design activities of user interface designers. There are certainly theory-based design methods prescribing the things that designers ought to do. Almost all of these have been developed from the perspective of descriptions of the user, rather than from consideration of the needs of designers – the current vogue for “user-centred design ” clearly expresses this emphasis on the user. According to this perspective, if user interface designers are to apply research into user needs, those designers must be able (and interested) to interpret and apply theoretical results. Alternatively, there are also many popular approaches to user interface design that have minimal theoretical grounding. Such design methodologies generally attempt to present designers with a checklist (Nielsen & Molich 1990) or a procedural list of design activities (Wharton, Rieman et. al. 1994) that will generate a good design. The reduction of design to a checklist or a predefined procedure is widely proposed in other areas of software development,