8317114
Decision theory and safety-critical interfaces
Risk assessment techniques are being used to support the engineering of complex, safety-critical systems. They help to identify those situations that pose the greatest threat to an application. They can also be used to inform interface development. For example, operators must be presented with additional contextual information during infrequent, high-cost failures. Many risk assessment techniques cannot represent the temporal properties that affect usability. Few techniques provide means of reasoning about user input or output. This paper presents means of overcoming these limitations. It is argued that temporal logic can be used to represent sequential and concurrent properties of interaction. The same notation can also be used to specify presentation requirements. Temporal logic does not, however, provide means of representing risk. Decision theory is recruited to introduce probability and cost into the notation. The logic is then applied to reason about the different effects that low frequency, high cost failures have upon a user interface. A limitation of this approach is that the extended logic provides little impression of what it would be like to interact with a stochastic application. Simulation tools have been developed to avoid this limitation.
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.
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.
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.
15495731
The Team-Based Operation of Safety-Critical Programmable Systems in US Commercial Aviation and the UK Maritime Industries
This paper analyzes a range of incidents involving team-based interaction with safety-critical programmable systems. The incidents were submitted to NASA’s Aviation Safety Reporting System (ASRS) and to the UK Marine Accident Investigation Branch (MAIB) between December 2001 and February 2003. Our results show that incidents, which complicated the team-based operation of safety-critical, computer systems in commercial aviation, are now being reported within the UK maritime industry. This reflects the increasing use of programmable navigation and collision avoidance devices both in ferry operations and in commercial fishing. For example, many incidents in both industries now stem from operators making inappropriate assumptions about the likely behavior of co-workers and their programmable systems even though part of their task is to actively monitor those activities. Our results also show that a growing number of incidents are triggered when teams must rapidly reprogram complex, safety-critical systems in response to unpredictable changes in their operational requirements.
9129216
A formal and structured approach to the use of task analysis in accident modelling
Recent work (Telford & Johnson, 1996; Johnson, 1997), involving the application of formal notations to analyse accident reports has shown that the quality of these accident reports is poor, so much so that their conclusions can be misleading. The proposed solution has been to use formal notations in combination with traditional analysis to produce a report, the conclusions of which can be verified by formal reasoning. However, there are weaknesses with the formal notations used up until now. Firstly, they have not allowed the representation of all aspects of an accident or incident. For example, human factors have either not been represented or not clearly delineated from system factors. In particular, there has not been an attempt to provide a task analysis of the incident. Secondly, the notations used do not easily facilitate the system engineering concepts of modularity, encapsulation or scalability. In consequence, it is difficult to model different aspects of an accident, compose these different aspects to build up the model or make changes to parts of the model without affecting the rest of the model. The purpose of this paper is to demonstrate how a formal object-oriented specification language can be used to provide the benefits offered by an engineering approach and in particular, by using this approach, how a task analysis model can be constructed. The task analysis incorporates Hollnagel's (1993) classification of erroneous actions, so that scenarios, deriving from human error, can be reasoned about. An air accident investigation report, issued by the UK Civil Aviation Authority, is used as a case study.
15670
Display of vector fields using a reaction-diffusion model
Effective visualization of vector fields relies on the ability to control the size and density of the underlying mapping to visual cues used to represent the field. In this paper we introduce the use of a reaction-diffusion model, already well known for its ability to form irregular spatio-temporal patters, to control the size, density, and placement of the vector field representation. We demonstrate that it is possible to encode vector field information (orientation and magnitude) into the parameters governing a reaction-diffusion model to form a spot pattern with the correct orientation, size, and density, creating an effective visualization. To encode direction we texture the spots using a light to dark fading texture. We also show that it is possible to use the reaction-diffusion model to visualize an additional scalar value, such as the uncertainty in the orientation of the vector field. An additional benefit of the reaction-diffusion visualization technique arises from its automatic density distribution. This benefit suggests using the technique to augment other vector visualization techniques. We demonstrate this utility by augmenting a LIC visualization with a reaction-diffusion visualization. Finally, the reaction-diffusion visualization method provides a technique that can be used for streamline and glyph placement.
2495230
Timbre interfaces using adjectives and adverbs
How can we provide interfaces to synthesis algorithms that will allow us to manipulate timbre directly, using the same timbre-words that are used by human musicians to communicate about timbre? This paper describes ongoing work that uses machine learning methods (principally genetic algorithms and neural networks) to learn (1) to recognise timbral characteristics of sound and (2) to adjust timbral characteristics of existing synthesized sounds.
8344660
Top Scientific Visualization Research Problems
Scientific visualization as currently understood and practiced is still a relatively new discipline. As a result, we visualization researches are not necessarily accustomed to undertaking the sorts of self-examinations that other scientists routinely undergo in relation to their work. Yet if we are to creat a disciplinary culture focused on matters of real scientific importance and committed to real progress, it is essential that we ask ourselves hard questions on an ongoing basis. What are the most important research issues facing us? What underlying assumptions needs to be challenged and perhaps abandoned? What practices need to be reviewed? In this article, I attempt to start a discussion of these issues by proposing a list of top research problems and issues in scientific visualization.
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.
30236643
Towards a Prehistory of Evolutionary and Adaptive Computation in Music
A number of systems have been created which apply genetic algorithms, cellular automata, artificial life, agents, and other evolutionary and adaptive computation ideas in the creation of music. The aim of this paper is to examine the context in which such systems arose by looking for features of experimental music which prefigure the ideas used in such systems. A number of ideas are explored: the use of randomness in music, the view of compositions as parameterized systems, the idea of emergent structure in music and the idea of musicians performing the role of reactive agents.