Ergonomic aspects of image polarity

The following paper deals with the question of whether VDUs with positive polarity or negative polarity are preferable from the ergonomic point of view. It discusses to what extent conditions are improved or impaired by changing the image polarity, using the visual performance and the sensitivity to interference as indicators. The basic visual functions of the user, adaptation flicker sensitivity, contrast sensitivity and visual acuity, are less influenced by changing the polarity than would be expected from classical investigations. The sensitivity to interference by reflections of environmental light on the VDU decreases. Because of the lower conspicuity of interference on VDUs with positive polarity, the design of VDU workplaces becomes more flexible. Together with a higher acceptance by the user, positive polarity will represent an ergonomic improvement in comfort.     

Contribution of ergonomics to the design of antireflection devices in the development of VDU workplaces

The design of the early Olivetti VDU workplaces used the micromesh filter as an antireflection device. New ergonomic problems related to the use of the VDUs have forced the designers to adopt the etching treatment on new VDUs and to supply them with the micromesh filter only in cases of particularly highly lit environments. Afterwards, in order to give the operator the opportunity of using the preferred colour of the character, the designers set up coloured plastic filters, which also show good antireflection effectiveness. In this case, the choice of correct colours and the determination of the best compromise between antireflection effectiveness and character sharpness are the contribution of ergonomics to the design of the filters. In this paper the different antireflection devices and their ergonomic evaluation are presented and discussed.     

Contribution of ergonomics to the design of antireflection devices in the development of VDU workplaces

Abstract

The design of the early Olivetti VDU workplaces used the micromesh filter as an antireflection device. New ergonomic problems related to the use of the VDUs have forced the designers to adopt the etching treatment on new VDUs and to supply them with the micromesh filter only in cases of particularly highly lit environments. Afterwards, in order to give the operator the opportunity of using the preferred colour of the character, the designers set up coloured plastic filters, which also show good antireflection effectiveness. In this case, the choice of correct colours and the determination of the best compromise between antireflection effectiveness and character sharpness are the contribution of ergonomics to the design of the filters. In this paper the different antireflection devices and their ergonomic evaluation are presented and discussed.     

Product development of an ergonomic keyboard

Abstract

The first truly ‘ergonomic’ keyboard for modern VDUs was shown to the public in April 1983 in Zurich. This split keyboard was the result of a research programme carried out by the Department of Hygiene and Work Physiology, ETH, Zurich. The ergonomic factors of the keyboard were convincing to the press, computer manufacturers and users. The steps from models of this keyboard to the final product and related problems of industrial design and engineering are explained. This will help in understanding the distinctive time lags between the results of scientific research and the availability of a product in the market–place.     

Product development of an ergonomic keyboard

The first truly 'ergonomic' keyboard for modern VDUs was shown to the public in April 1983 in Zurich. This split keyboard was the result of a research programme carried out by the Department of Hygiene and Work Physiology, ETH, Zurich. The ergonomic factors of the keyboard were convincing to the press, computer manufacturers and users. The steps from models of this keyboard to the final product and related problems of industrial design and engineering are explained. This will help in understanding the distinctive time lags between the results of scientific research and the availability of a product in the market-place.     

Method for measuring jitter in VDUs

A method for measuring jitter in visual display units (VDUs) is proposed. The method is based on the fact that jitter is revealed by a variation in pulse amplitudes when the electron beam traverses in paths which are displaced in relation to each other. The obtained data demonstrate that frequency characteristics of jitter are of the white noise type. The pulse amplitude properties on the other hand appear to provide a promising basis for measuring jitter in VDUs.     

Implementing the directive for VDU work- the EU-state of the art

In order to improve occupational health and safety conditions in the workplace, several national directives and international standards have been defined. In 1990 the European Union (EU) defined such a directive, i.e. a minimal set of ergonomic requirements that should be met at workplaces equipped with Visual Display Units (VDUs). In order to put the directive to work, existing measurements have been reviewed to evaluate how far they support the implementation of the directive. The instrument that should be used finally for checking VDU-workplaces should not hinder the work flow and the organizational development of a company. The instrument should rather support the effective evaluation of all VDU-workplaces according to the directive. The investigations in this paper focus on the analysis of 18 techniques for measurement stemming from different disciplines. The directive addresses several different perspectives including human cognition, organization of work and technical features. However, an absence of comprehensive measurements has been identified. Most of the existing techniques for measurement focus either on users, user interfaces or on organizational issues. In order to support the development of a comprehensive instrument to check the minimal requirements of the EUdirective EU-CON, a technique for evaluation and re-design of VDU-work has been developed.     

Evaluation of presentation of information for process control operations

In an experimental process control simulation study two operators performed monitoring and control operations including safety critical tasks that required parallel processing of information distributed over different functional mimic displays. The assignment of mimic displays to Visual Display Units (VDUs) was experimentally varied by allowing one or two VDUs for mimic presentation. The study revealed no evidence for differences in task performance during normal process control operations. During abnormal operations, however, detrimental effects both on performance and work load were observed. Having only one VDU available for mimic display revealed either a lower level of performance (time for fault management) and/or a higher level of emotional work strain. It is concluded that decisions on the number of VDUs necessary for effective and efficient process control must refer to the tasks to be performed and the presentation of information necessary for a safe, effective and efficient task performance under critical, but not only normal conditions.     

Implementing the directive for VDU work- the EU-state of the art

In order to improve occupational health and safety conditions in the workplace, several national directives and international standards have been defined. In 1990 the European Union (EU) defined such a directive, i.e. a minimal set of ergonomic requirements that should be met at workplaces equipped with Visual Display Units (VDUs). In order to put the directive to work, existing measurements have been reviewed to evaluate how far they support the implementation of the directive. The instrument that should be used finally for checking VDU-workplaces should not hinder the work flow and the organizational development of a company. The instrument should rather support the effective evaluation of all VDU-workplaces according to the directive. The investigations in this paper focus on the analysis of 18 techniques for measurement stemming from different disciplines. The directive addresses several different perspectives including human cognition, organization of work and technical features. However, an absence of comprehensive measurements has been identified. Most of the existing techniques for measurement focus either on users, user interfaces or on organizational issues. In order to support the development of a comprehensive instrument to check the minimal requirements of the EUdirective EU-CON, a technique for evaluation and re-design of VDU-work has been developed.     

Standards-Point/counterpoint: safety standards for CRT visual display units

The alleged health hazards of prolonged exposure to computer monitors which have engendered much discussion in the industry and in legislative bodies, are discussed from two different viewpoints. Ashley states that, in terms of measured quantities and current knowledge of biological interactions, only the ELF electric fields near visual display units (VDUs) have the possibility of a significant biological effect on human tissue. Any frequency magnetic field exposure near VDUs is biologically insignificant. Buckley lists his objections to the content of Ashley's arguments.<>     

Perceptual thresholds for jitter in VDUs

An experimental determination of perceptual thresholds for jitter in VDUs is reported. For jitter of a vertical line in a highly structured surround the jitter thresholds (jitter amplitude) varied between 5 and 10 seconds of arc depending on the frequency of the jitter. For jitter generated in a VDU designed for text presentation the displacement threshold of jitter (with a 10% criterion) was found to be 29 seconds of arc.     

Hardware for visual information: Displays and systems

A review of hardware for visual purposes, which is broadly classified into light emitters (CRTs, alphanumeric VDUs and television displays) and light controllers (eidophors, cathodochromic tubes, photochromatic displays and liquid crystals), is presented. It includes sections on constrained-format, head-mounted and solid-state displays, soft and hard copy, including printers and plotters, and interaction methods.     

An ergonomic expert system for risk assessment of work-related musculo-skeletal disorders

A computer-based expert system (SONEX) was developed to identify ergonomic risks for work-related musculoskeletal disorders (WRMSDs) in a wide variety of jobs and provide expert prevention advice. SONEX uses a rule base and 6 knowledge base modules: WRMSD risk factors are grouped into two main knowledge base modules (symptoms, engaged body part) with four supplementary knowledge base modules (work environment, work chair, work tools, organization factors). SONEX uses a menu-based interface and a series of simple questions that lead a user through each of the two main modules. Based on user responses it then recommends other knowledge base modules that are relevant for a detailed analysis of work risks. The SONEX rule base has over 140 questions, the knowledge base includes over 200 risk factors, and around 500 possible answers can be generated. SONEX relates ergonomic shortcomings in the job with worker's subjective symptoms; it predicts possible WRMSDs; and it offers preventive suggestions for ergonomic improvements to the job to prevent WRMSDs. It has been tested in a variety of work places with known ergonomic problems and with known employee WRMSDs by comparing its performance with conventional analytical methods and results show that it accurately predicts possible WRMSD risks and identifies ergonomic shortcomings. The advantages of SONEX are that it is much faster than other ergonomic analysis methods and it can be used by ergonomists and other professionals and also by workers themselves.     

Multilink — an open network for personal computers

Multilink is an open, local area network originally intended for connecting user terminals and other peripherals into multiple access computing and telecommunications facilities. Today, users tend to have personal computers rather than ‘dumb’ VDUs, and the network has proved fast enough to support shared disc facilities. The design of the network is described, followed by a review of the support software required for use with personal computers.     

Development of an ergonomic evaluation facility for Indian tractors

The design of tractors manufactured in low-income countries like India has not changed much in the past two decades, especially from an ergonomic point of view. Moreover, in these countries tractors are used for transportation purposes in addition to farming operations. Therefore, the design criteria for these tractors need to be different from those in high-income countries. This paper describes the development of an ergonomic facility for improvement of tractor design. An ergonomic evaluation facility has been developed consisting of a work place envelope for the Indian population, a layout measuring device and an ergonomic rig. This facility can be used for comparative evaluation of the display and control layouts of different tractors in order to develop an optimum layout. The ergonomic rig has the facility to simulate the improved layout for subjective evaluation.     

A generic algorithm for computing optimal ergonomic postures during working in an industrial environment

The present study tries to decrease the risk of work-related musculoskeletal disorders for industry workers by proposing a generic algorithm that recommends an optimal ergonomic posture for accomplishing tasks in an industrial environment. In the case of a dangerous ergonomic pose, the optimization algorithm starts by heuristically changing it to a more ergonomic one. Each recommended posture's feasibility is tested with an inverse kinematic method that can predict the worker's behavior for accomplishing a task. This iterative optimization procedure continues until the optimal ergonomic pose for the worker is achieved. The algorithm's validity is tested in thirteen cases, people with different gender (50 percent male, 50 percent female) aged between 20 and 35, and different height and body morphologies. According to studies, there is a connection between musculoskeletal disorders and the wrong posture for accomplishing tasks in industries. We suggest an optimization algorithm that can indicate the worker the optimal ergonomic pose by considering task constraints in real-time.     

Designing a Telephone-Based Interface for a Home Automation System

User-interface design lacks expertise in designing nonvisual user interfaces. This is surprising as there are various domains where auditory interfaces have already been proved to be helpful, such as railway information services and reading support for blind persons.

We present a case study concerning the design of a telephone-based interface (TBI). It was realized within the development process of an interaction concept for a modular home automation system. The design was based on requirements gathered in user focus groups and on general guidelines for the design of TBIs. The TBI's evaluation revealed some minor (i.e., easily solved) usability problems. Questionnaires showed a positive ergonomic quality as well as a positive overall appeal. Interestingly, the evaluation indicates a potential to improve hedonic quality (i.e., non-task-related quality aspects). It may be induced by the addition of nonspeech sounds, thereby enriching user experience.     

Job stress management and ergonomic intervention for work-related upper extremity symptoms

In practice the secondary prevention of work-related upper extremity (WRUE) symptoms generally targets biomechanical risk factors. Psychosocial risk factors have also been shown to play an important role in the development of WRUE symptom severity and future disability. The addition of a stress management component to biomechanically focused interventions may result in greater improvements in WRUE symptoms and functional limitations than intervening in the biomechanical risk factors alone. Seventy office workers with WRUE symptoms were randomly assigned to an ergonomics intervention group (assessment and modification of work station and stretching exercises) or a combined ergonomic and job stress intervention group (ergonomic intervention plus two 1-h workshops on the identification and management of workplace stress). Baseline, 3- and 12-month follow-up measures of observed ergonomic risks and self-reported ergonomic risks, job stress, pain, symptoms, functional limitation, and general physical and mental health were obtained from all participants. While both groups experienced significant decreases in pain, symptoms, and functional limitation from baseline to three months with improvements continuing to 12 months post baseline, no significant differences between groups were observed for any outcome measures. Findings indicate that the additional two-session job stress management component did not significantly enhance the short- or long-term improvements brought about by the ergonomic intervention alone.     

A software‐based method for ergonomic posture assessment in automotive preproduction planning: Concordance and difference in using software and personal observation for assessments

This article describes the pilot study for testing a system for ergonomic posture assessment. 1 The software‐based approach for ergonomic assessment is based on motion capturing work tasks using realistic mock‐ups of the assembly environment. The approach for ergonomic assessment reduces the expenditure of time for evaluation. This may lead to considerable ergonomic aspects during the early stages of production planning. A comparative test between human observers and the software system was carried out. The test of the system focuses on correct recognition of postures from the motion data and compares the computer‐based evaluation with the results of a manual analysis carried out by a human observer. The tests indicate sufficient results for the automated assessment, especially for the arm and leg postures. But there is still some potential for further improvement of the recognition accuracy of the back postures. © 2011 Wiley Periodicals, Inc.     

Development of the electronic service system of a municipal clinic (Based on the analysis of foreign web resources)

The problem of designing a municipal clinic website and selecting a number of its elements ensuring proper, ergonomic, and easily accessed services is discussed. The poor performance of the website infrastructure of state and municipal healthcare institutions necessitated an analysis of web resources used in different countries at different stages in providing healthcare services. The information resources of healthcare institutions in the United Kingdom, USA, and Germany were studied according to three existing healthcare economic models.