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.
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.
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.
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.
28212389
Biomedical computing and visualization
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.
17446260
Genetic Programming with Fitness Based on Model Checking
Model checking is a way of analysing programs and program-like structures to decide whether they satisfy a list of temporal logic statements describing desired behaviour. In this paper we apply this to the fitness checking stage in an evolution strategy for learning finite state machines. We give experimental results consisting of learning the control program for a vending machine.
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.
12725153
Computational Engineering and Science Program at the University of Utah
The grand computational challenges in engineering and science require for their resolution a new scientific approach. As one report points out, “The use of modern computers in scientific and engineering research and development over the last three decades has led to the inescapable conclusion that a third branch of scientific methodology has been created. It is now widely acknowledged that, along with traditional experimental and theoretical methodologies, advanced work in all areas of science and technology has come to rely critically on the computational approach.” This methodology represents a new intellectual paradigm for scientific exploration and visualization of scientific phenomena. It permits a new approach to the solution of problems that were previously inaccessible.