Distributed accessibility control points help deliver a directly accessible Web

This paper describes a set of interfaces and mechanisms to enhance access to the World Wide Web for persons with sensory, cognitive, or motor limitations. Paradoxically, although complex Web architectures are often accused of impeding accessibility, their layers expand the range of points where interventions can be staged to improve it. This paper identifies some of these access control points and evaluates the particular strengths and weaknesses of each. In particular, it describes an approach to enhance access that is distributed across multiple control points and implemented as an aggregation of services. Published online: 6 November 2002     

Investigating the Work of Industrial Schedulers through Field Study

The study of planning and scheduling from a human factors perspective has re-emerged as an important area for research in contemporary manufacturing enterprises. Improved decision support systems are needed that optimally integrate people with computer-based systems in order to increase productivity and responsiveness. However, there is a dearth of knowledge on the reality of the human factors of planning and scheduling practice across manufacturing industry. This paper reviews previous studies of scheduling practice and demonstrates the lack of clearly reported and justified methods to study scheduling behaviour and to interpret and represent the findings. Field study is proposed as the most appropriate approach for carrying out studies of scheduling in practice and various methods used in scheduling field studies are specified. Particular emphasis is given to the investigation of the nature of planning and scheduling practice in the context of a functionally, spatially and temporally complex environment.     

Platitudes and attitudes

In October 2002 I attended the Ninth Monterey Software Engineering workshop held in Venice, Italy. This year’s theme was titled “Radical Innovations of Software and Systems Engineering in the Future.” In preparing my talk for the workshop, I thought hard about what I could possibly say on this topic that would not sound stupid. I certainly thought it would be awfully presumptious of me to predict how people will or should be developing software in the future. More easily, I could imagine what the systems of tomorrow will look like and who will be developing them, though anything I would say would sound like platitudes. I could also state some strong opinions about what matters and what doesn’t in the process of software development. Stating such attitudes would at least provoke some discussion. Hence, what follows captures some of what I said at the workshop. Published online: 10 April 2003     

Specification and validation of a concurrent system: an educational project

For several years we have been in charge of a course on specification and validation of concurrent and reactive systems. At the end of this course, the students must carry out a project dealing with a model railway. They have to specify the railway, validate their model, and finally translate it into a program controlling the model railway with up to five trains. In this paper, after presenting the project, we describe how the railway is specified and checked, step by step, by the students. We also explain how the analysis results lead to a policy for the switch control. Finally, we include some remarks about the implementation. Published online: 24 August 2001     

A workshop on formal methods education: held at Melbourne Florida in March 1998[5]

The 21st Century Engineering Consortium Workshop was devoted to educational issues in the area of formal methods. This article summarizes opinions and perspectives which emerged at the workshop and sketches a context for their assessment. There was broad agreement that advances in education are crucial to expanding formal methods practice. However, specific recommendations vary among interest groups and individuals. In this multi-faceted area, it is important to establish a framework for debating issues and presenting them to the broader community. Nowhere is this need greater than in discussions of education.     

Extra-Ordinary Human–Machine Interaction: What can be Learned from People with Disabilities?

When specifying, designing and implementing technology for work, it is very important to consider the whole of the potential user group, and not to forget that this might include people with disabilities. Obvious reasons for this are demography, disabled people forming a significant and growing proportion of the workforce, and legal obligations caused by equal opportunities legislation. There are more subtle reasons, however, which link so-called ‘disabled people’ with the rest of the population. The paper notes that most people have some disabilities, sometimes temporarily due to accident, or permanently due to ageing and other processes. In addition it notes that even otherwise fully functioning people can be seriously handicapped by hostile environments, and a parallel is drawn between the human interface needs of disabled people operating in ordinary situations and able-bodied people operating in high workload and stress situations. The paper concludes by suggesting a research agenda for the field on the basis of these considerations.     

Presentations for databases in multimedia environments

The problem of presenting database query results has not been investigated sufficiently. This work proposes an approach to identify effective presentations for the results of database queries. This will be done by considering different kinds of information, such as user goals, the characteristics of the data to be presented, and the relationships among them. Our approach is based on the definition of composition operations which, on the basis of elementary presentation types, allow us to obtain designs of complex final presentations. Some effectiveness criteria are considered in order to identify those presentations which best match the user's goals and cognitive abilities. We consider multimedia environments at both the data and presentation level.     

A Taxi Ride to Late Capitalism: Hypercapitalism, Imagination and Artificial Intelligence

Through analogy this paper draws attention to hypercapitalism, that is, the profitability of the processes of economic recirculation that are independent of a materialist reality. Since neither materialist ideology nor perception are any longer at stake in hypercapitalism this opens the way for other realities to be revisited. In particular, this paper suggests that this radical shift in the logic of the economy resonates with the values of the Mediaeval period. The paper concludes by suggesting that the study of human consciousness may benefit from a new relationship with reason, particularly as we consider such terms as artificial and intelligent. Correspondence and offprint requests to: Michael Punt, Editor in Chief, Leonardo Digital Reviews, 26 Bridge Street, Chepstow, Monmouthshire NP16 5EZ, UK. Email: mpunt@easynet.co.uk     

Laziness pays! Using lazy synchronization mechanisms to improve non-blocking constructions

Summary. We present a simple and efficient wait-free implementation of Lazy Large Load-Linked/Store-Conditional (Lazy-LL/SC), which can be used to atomically modify a dynamically-determined set of shared variables in a lock-free manner. The semantics of Lazy-LL/SC is weaker than that of similar objects used by us previously to design lock-free and wait-free constructions, and as a result can be implemented more efficiently. However, we show that Lazy-LL/SC is strong enough to be used in existing non-blocking universal constructions and to build new ones. Received: December 2000 / Accepted: September 2001     

Lexically-generated subject hierarchies for browsing large collections

Developing intuition for the content of a digital collection is difficult. Hierarchies of subject terms allow users to explore the space of topics that a collection covers, to form and specialize useful query terms, and to directly identify interesting documents. We describe two interfaces for navigating such hierarchies, and present a technique for inferring hierarchies automatically from large corpora. We also discuss scalability issues for the techniques involved, and our solutions to these problems. Received: 15 December 1997 / Revised: June 1999     

Direct linear sub-pixel correlation by incorporation of neighbor pixels' information and robust estimation of window transformation

Standard methods for sub-pixel matching are iterative and nonlinear; they are also sensitive to false initialization and window deformation. In this paper, we present a linear method that incorporates information from neighboring pixels. Two algorithms are presented: one ‘fast’ and one ‘robust’. They both start from an initial rough estimate of the matching. The fast one is suitable for pairs of images requiring negligible window deformation. The robust method is slower but more general and more precise. It eliminates false matches in the initialization by using robust estimation of the local affine deformation. The first algorithm attains an accuracy of 0.05 pixels for interest points and 0.06 for random points in the translational case. For the general case, if the deformation is small, the second method gives an accuracy of 0.05 pixels; while for large deformation, it gives an accuracy of about 0.06 pixels for points of interest and 0.10 pixels for random points. They are very few false matches in all cases, even if there are many in the initialization. Received: 24 July 1997 / Accepted: 4 December 1997     

Continuity in cognition

Designing for continuous interaction requires designers to consider the way in which human users can perceive and evaluate an artefact’s observable behaviour, in order to make inferences about its state, and plan and execute their own continuous behaviour. Understanding the human point of view in continuous interaction requires an understanding of human causal reasoning, of the way in which humans perceive and structure the world, and of human cognition. We present a framework for representing human cognition, and show briefly how it relates to the analysis of structure in continuous interaction, and the ways in which it may be applied in design. Published online: 14 May 2002     

Linguistic Problems with Requirements and Knowledge Elicitation

Human and conversational aspects of requirements and knowledge identification are employed to show that requirements ‘engineering’ is not the same as civil engineering or scientific problem solving. Not only can requirements not be made fully explicit at the start of a project, they cannot be made fully explicit at all. A need is identified to enhance computer-based information systems (CBIS) development methods to accommodate: plurality of incommensurable perspectives, languages and agendas; dynamic representations of system features that can be experienced rather than abstracted and forced into an abstract paper-based representation; recognition that CBIS development is in general a continuous process where users changing their minds is a natural and necessary indication or organisational vitality.  It is suggested that prototyping and rapid application development go some way to addressing these requirements but that they require further development in the light of the theoretical light thrown on the nature of the problem.     

The New Frontier Issues for Cognition Technology

Cognitive engineering has developed enormously over the last fifteen years. Yet, despite many excellent research projects and publications, its full potential has not been embraced into mainstream system design. This paper will examine the reasons for this failure and argue that the problem is not simply inertia or lack of education. There are strong organisational influences that cause resistance to this particular approach. The discipline itself has characteristics that make it fragile in the modern corporate structure. In addition, the cognitive engineers themselves are not blameless in the equation. They appear to have done exactly what they criticise the engineering community for doing: they have packaged their product in a manner that is not ‘user friendly’ to its target population, not structured to suit its application, and not output in the format required. Suggestions will be made to rectify the situation: a list of actions is proposed for practising cognitive engineers to make their product more likely to enjoy widespread uptake.     

A subdivision scheme for hexahedral meshes

Published online: 23 July 2002     

Handwriting recognition or reading? What is the situation at the dawn of the 3rd millenium?

During the last forty years, Human Handwriting Processing (HHP) has most often been investigated under the frameworks of character (OCR) and pattern recognition. In recent years considerable progress has been made, and to date HHP can be viewed much more as an automatic Handwriting Reading (HR) task for the machine. In this paper we propose the use of handwriting invariants, a physical model for a first segmentation, a logical model for segmentation and recognition, a fundamental equation of handwriting, and to integrate several sources of perception and of knowledge in order to design Handwriting Reading Systems (HRS), which would be more universal systems than is currently the case. At the dawn of the 3rd millennium, we guess that HHP will be considered more as a perceptual and interpretation task requiring knowledge gained from studies on human language. This paper gives some guidelines and presents examples to design systems able to perceive and interpret, i.e., read, handwriting automatically. Received October 30, 1998 / Revised January 30, 1999     

Preface by the section editor

Preliminary versions of the papers of this special section originally appeared in the proceedings of the 6th edition of the conference “Tools and Algorithms for the Construction and Analysis of Systems” (Tacas) held in Berlin early April 2000 as a constituent event of the European joint conferences on Theory and Practice of Software. All papers present tools relevant in the context of systems validation. The first three focus on extensions or particular applications of model-checking techniques, whereas the fourth is about integration of design tools with validation tools, in particular theorem provers and model-checkers. Published online: 24 January 2003