Olov Östberg

Accommodation and visual fatigue in display work

Abstract Being in the midst of the evolution of the species Homo termino-videns, demands for (eye) rest-time allowances are commonplace among vdu operators the world over. Today some 13 per cent of Swedish salaried employees daily sit at a vdu and Sweden is the first country to have issued national safety and health directives on vdu work. Experiments using a laser optometer have shown that visual tasks in vdu work may induce temporary effects in the visual accommodation system; increased refractive power in darkness (‘night myopia’) and levelling-out of accommodation responses in good lighting (‘distance myopia’ and ‘near hyperopia’). It is believed that laser optometry will eventually make possible the formulation of objective criteria of visual fatigue and its prevention.

Channeling knowledge: Expert Systems as communications media

Expert Systems (ES) are as yet imperfectly defined. Their two consistently cited characteristics are domain knowledge and expert-level performance. We propose that current structural definitions are inadequate and suggest a view of ES as communication channels. We proceed to explore the factors influencing applicability of ES technology to an enterprise and the impacts that could be expected. A consequence of this view is the idea of incremental information loss on the path from the expert to the ES user. Strategies for minimizing this loss derive naturally from our perspective and are evident in successful ES.

MTFA as a measure for computer display screen image quality

Abstract Computer display screen image quality is known to vary widely. Attempts have been made the world over at defining objective scales to better assess image sharpness and clarity. The experiments reported here were stimulated by the recent US adoption of MTFA≥5 as a minimum quality criteria. A series of ten hard-copy photographs and seven retrievable display screens were developed for a monochrome, cathode ray tube terminal that differed only in objective image quality. This series of display screen images was presented to 22 office workers, who were asked to provide a subjective image quality judgement in the form of a numerical scale ranking. The subjects were instructed to match the display screen with photographs that they estimated to be most comparable in image quality. Finally, the subjects were asked to specify what they considered to be the minimum acceptable visual quality. It was found that the subjects could accurately rank low and minimum quality display images and that their subjective visual quality judgement corresponded well with the objective MTFA quality scale. The minimum acceptable display quality specified by the office worker group corresponded to MTFA≥7, which is substantially higher than the US criteria and would disquality 40% of the video display terminals currently marketed in Sweden.

Social Aspects of Computer Use

Publisher Summary This chapter discusses the social aspects of computer use. The social aspects of the human–computer interaction emphasize the need to anticipate a variety of issues and fundamental conflicts, and plans carefully to resolve them. To remain viable, modern organizations should attempt not only to forecast the future with precision but should also attempt to influence the future. Many choices about change are involved when contemplating human work with computerized systems. The solutions to problems posed by human computer interaction are usually not individual choices but instead organizational and social choices. In some cases, beneficial outcomes are available that trade-off productivity gains against detriments to health or work quality. There are also a large number of types of changes that favorably affect both working lives and economic results. Focusing on the points where the gains in work–life quality and monies intersect requires opening up the decision-making process; deliberate, conscious planning; careful equipment acquisition strategies; gradual implementation; inevitably making some mistakes; and enhancing capabilities for continuing improvements and refinements after new systems are in place.

Expert Systems in a Social Environment—Human Factors Concerns

There is an abundance of promises for Expert Systems with user-friendly and intelligent interfaces providing cloned expertise for augmented job performance. A closer look reveals that very few systems are in operation, and that there is a serious gap between claims and reality. Basically, “Knowledge Engineering” is a modern form of “Work Study Engineering”, and yet job and organizational design issues are rarely addressed in the literature on designing Expert Systems. This serious gap is discussed.There is an abundance of promises for Expert Systems with user-friendly and intelligent interfaces providing cloned expertise for augmented job performance. A closer look reveals that very few systems are in operation, and that there is a serious gap between claims and reality. Basically, “Knowledge Engineering” is a modern form of “Work Study Engineering”, and yet job and organizational design issues are rarely addressed in the literature on designing Expert Systems. This serious gap is discussed.

Expert Systems: Channels for Dialogue

The chapter examines biases underlying current expert systems (ESs) characterizations. These biases concern direction of knowledge flows in a consultation, the communicational competence of the consultee, the nature of the knowledge transferred, and the accuracy with which an ES mimics the expert. The chapter then discusses information loss in the ES channel. By showing that such losses occur from the consultee to the consultant, the authors argue that consultation is a bidirectional process; the consultee provides notification and description, and the consultant provides advice or answers. The consultative process can therefore be described in terms of conversational interaction between consultee and consultant, and insights into this form of interaction - or consultative dialogue - can be gained from analysis of existing models of conversational interaction (e. g. from linguistics). Only by considering such models can we arrive at a serious, unbiased appraisal of ES value and their impact within workplace settings.

CRT flicker and scan-line direction

Abstract A brief review of the literature covering the perception of flicker is followed by a description of experiments to investigate flicker mechanisms, using a VDU with a light background and with a minimum refresh rate of 70 Hz. A previous hypothesis that there is a link between scan-line direction and perception of flicker was not upheld, although there was support for the view that 70 Hz may not be a high enough refresh rate to ensure freedom from flicker in large displays.

Tagging municipality FAQs: a quest for interoperability

All organisations must be able to answer questions from their respective constituencies. It is not an exaggeration to say that, in this respect, it is a challenge to handle the extremely broad action platform of local government administrations (municipalities). The present paper is a walk-through of questions from the citizens that are managed at Botkyrka municipality, Sweden. It is focussed on the use of an ‘intelligent’ citizen assistant.