10158972
On the Problems of Validating DesktopVR
For the last twenty years, human-computer interfaces have been dominated by two-dimensional interaction techniques. Things are changing. Techniques that were previously restricted to specialized CAD/CAM tools and immersive VR systems are now being extended to the mass market. The photo-realistic facilities offered by QuicktimeVR and the model based renderings of VRML (Virtual Reality Mark-up Language) provide sophisticated tools for interface design. As a result, three dimensional visualization techniques are being widely exploited in the financial services industry, airports and even off-shore oil production. In January 1997, there were some 2,000 VRML models on the web. By January 1998, this number had grown to over 20,000. Research in human-computer interaction has, however, lagged behind these developments. Few guidelines can be applied to support the design of desktopVR. This paper, therefore, describes three criteria that can be applied to assess the usability of these interfaces. We then go on to validate these criteria against a number of case studies. Unfortunately, it is concluded that standard measures of task performance, successful navigation and subjective satisfaction cannot easily be applied to assess the utility of 3D systems.
59685614
Supporting Error-Driven Design
This paper argues that two limitations restrict the utility of interface specification languages. Firstly, they provide no means of capturing the cognitive conditions that lead to operator ‘error’. This makes it difficult to distinguish between the normal behaviour of an expert and the mistakes that often lead to problems for novices. The second weakness is that interface notations cannot easily be used to represent and reason about asynchronous failures. This prevents designers from identifying solutions to failures that could occur at many different points during interaction. These are significant limitations because they reflect a pre-occupation with normative behaviour. Unless we have some means of analysing system failure and operator error then we will continue to have interfaces that are designed to support perfect users in perfect environments.
52833794
The Role of Night Vision Equipment in Military Incidents and Accidents
Night vision devices provide enormous benefits. They enable personnel to carry out operations under conditions that would not otherwise be possible. However, these benefits carry considerable risks. For instance, individuals often become over confident about their ability to use image intensification and infrared devices. In consequence, the use of night vision equipment is an increasingly common factor in military incidents and accidents. This paper uses an analysis of incident and accident data to identify requirements for the successful deployment of night vision equipment. It is argued that these applications must be integrated more closely with existing navigational systems. The successful application of this technology also depends upon adequate risk assessment and team-based training.
47143488
The Evaluation of User Interface Notations
Over the last decade a wide range of graphical, tabular and textual notations have been proposed to support the design of human-computer interfaces. These notations are intended to strip away the clutter of implementation details that frequently obscure interaction properties. Unfortunately, relatively little work has been done to evaluate the usability of these notations for ‘real-world’ interfaces. We have, therefore, conducted an empirical evaluation of the User Action Notation (UAN), State Transition Networks (STN) and temporal logic ‘in the wild’. By this we mean that our subjects were drawn from realistic samples of users and designers. We also presented our subjects with realistic descriptions of two user interfaces. This avoids a weakness of previous investigations that have used ‘toy examples’. The results of our investigation show a strong preference amongst our subjects for the use of natural language descriptions. More surprisingly, our results also suggest a link between the frequency of comprehension errors and positive attitude statements towards particular notations. In other words, our subjects made most errors with the notations that they liked the best. This suggests that while graphical notations, such as state transition networks, have a strong intuitive appeal they may also create significant problems for real-world development tasks.
18914756
The Impact of Time and Place on the Operation of Mobile Computing Devices
Recent improvements in the quality and reliability of wireless communications has led to the development of a range of mobile computing devices. Many portable computers now offer modem connections through cellular and satellite telephone networks. Taxi services, emergency vehicles, domestic repair teams all now rely upon mobile links to central computing systems. In spite of these advances, a number of technical problems still affect the quality of interaction with mobile applications. Electromagnetic interference blocks radio signals. Obstacles in the line of sight can interrupt microwave and infra-red transmissions. Tracking problems frustrate the use of low-level satellites. Transmission delays affect the service provided by higher, geostationary satellites. From the users’ point of view, these problems manifest themselves as geographical constraints upon the usability of their ‘mobile’ device. This lead to delays in the transmission of critical information. These, in turn, lead to the frustration and error that often complicates the operation of mobile computer systems. In the short term, it seems unlikely that the technical limitations will be resolved. The following pages, therefore, argue that interface designers must consider means of reducing the impact of geographic allocation upon the operation of mobile computing devices.
846602
Incident and Accident Investigation Techniques to Inform Model-Based Design of Safety-Critical Interactive Systems
The quality of the design of an interactive safety-critical system can be enhanced by embedding data and knowledge from past experiences. Traditionally, this involves applying scenarios, usability analysis, or the use of metrics for risk analysis. In this paper, we present an approach that uses the information from incident investigations to inform the development of safety-cases that can, in turn, be used to inform a formal system model, represented using Petri nets and the ICO formalism. The foundations of the approach are first detailed and then exemplified using a fatal mining accident case study.
6901876
Location History in a Low-cost Context Awareness Environment
Location awareness is a crucial part of the context-awareness mechanism for ubicomputing. This paper explores how usefull is the location awareness history for an office based low-cost context-awareness environment. Capturing location awareness data into a relational database is simple and feasible in office environment. We use extended SQL to access the location awareness history database to provide direct support for speech commands. The mechanism improve flexibility for developing context awareness application in the Intelligent Environment.
40520811
A note on cospectral graphs
Abstract The notion of a (1, x ) adjacency matrix is introduced, together with methods for dealing with it. It is shown that in many instances this adjacency matrix is superior to the usual (0, 1) adjacency matrix, and will distinguish cospectral pairs, when the latter will not. In those cases in which the (1, x ) adjacency matrix fares no better than the (0, 1) adjacency matrix, a good deal can be said about the matrices by which the cospectral pairs are similar.
31563337
The trees for which maximum multiplicity implies the simplicity of other eigenvalues
Among those real symmetric matrices whose graph is a given tree T, the maximum multiplicity is known to be the path cover number of T. An explicit characterization is given for those trees for which whenever the maximum multiplicity is attained, all other multiplicities are 1.
18085576
Semantic errors - diagnosis and repair
In compiler technology, semantic error handling has too often used ad hoc techniques and terse messages of fixed content. In contrast, we present general models of diagnosis and repair of semantic errors and illustrate their use in the York Ada Workbench Compiler. The diagnostic model focuses upon the problem of selecting suitable information from which the programmer can locate and correct an error; following a brief discussion of an approach in which <underline>filters</underline> are applied to reports, and we give a more extensive account of a new approach using an <underline>interactive diagnostic interpreter</underline>. The repair model is based upon the idea of <underline>plastic</underline> nodes which are introduced into the compiler's internal representation of a program to replace <underline>normal</underline> nodes which are missing or erroneous.
21779382
Computational Engineering and Science Program at the University of Utah
We describe a new graduate program at the Univesity of Utah that we consider a first step towards the modernization of the University's curriculum in what we call "Computational Engineering and Science" (CES). Our goal is to provide a mechanism by which a graduate student can obtain integrated expertise and skills in all areas that are required for the solution of a particular computational problem.