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CRTs pose health problems for operators
ahead, the sifting of this information and the recognition of its relevant features, and the decision on what the vehicle should be made to do in the unfolding situations.
8.2.8 (70855) Hopkin, V.D. The provision and use of information on air traffic control displays. In: AGARD plans and developments for air traffic systems, Feb 1976, 12 pp; abstr in Scientific and Technical Aerospace Reports (Report No AGARD-CP-188). Several kinds of mismatch can occur at the man machine interface in air traffic control systems. One, often overlooked, concerns the provision of certain essential information in a form which is unusable. The traditional reliance on the man's strengths of adaptability and flexibility in order to match man and machine in the system is thwarted if he cannot use the information presented to him. Changes from qualitative to quantitative information, incomplete automation, and the apparent retention of decision making roles which in fact have been greatly modified, all pose problems of ensuring that the displayed information has been adapted successfully.
Factors affecting perceptual motor processes 8.2.9 (70864)
Ostberg, O. CRTs pose health problems for operators. International Journal of Occupational Health and Safety, Nov/Dec 1975, 44.6, 2 4 - 2 6 ; abstr in Electrical and Electronics Abstracts. Discusses hazards of cathode-ray tube display terminals in offices, ranging from discomfort to pain and extreme visual fatigue. Examines the interrelationships of the work environment which includes lighting and workplace layout, the work object (paperwork, computer display screen ere) and the worker.
what is good for the system is not always good for the system operator. Microimage viewing equipment is invariably introduced into offices as 'another job aid', without the necessary adjustments being made to the ambient illumination and workplaces. Furthermore the equipment itself and the microfilmed material may be of poor quality. Consequently, complaints of eye strain, visual discomfort, difficulties in reading and postural fatigue due to long term use of readers are commonplace. A literature review indicates that the 'microimage trade' is aware of these facts, but worker complaints are still numerous. Obviously, 'technical development' by itself does not create improved working conditions for the operator - Occupational Health regulations need to be developed. It must be realised that microimage reading is a demanding visual task that calls for purpose-designed workplaces, working environments, and job routines. The trend now discernible in large microimage systems is that persons above the age of 50 are visually handicapped' and unsuited for long term work at the readers. Such a trend indicates a serious inadequacy in present microimage systems. 8.2.11 (70886) Klein, K.E. et al Air operations and circadian performance rhythms. In: AGARD higher mental functioning in operational environments, Apr 1976, 12 pp; abstr in Scientific and Technical Aerospace Reports (Report No AGARD-CP-181 ; ISBN-92-835-1216-2). Experimental results and pertinent data from literature on circadian behavioural rhythms and their modifications through various factors are reviewed. Considered are operations of airerews round the clock and on transmeridian routes; some possibilities of appropriate scheduling are discussed.
Physiology, anthropometry and biomechanics
8.2.10 (70865) Ostberg, O. Review of visual strain, with special reference to micro-image reading. Paper presented at the International Micrographics Congress, Stockholm, Sweden, 28-31 Sap 1976, 10 pp.
8.2.12 (70900) Owings, C.L. et al Strength characteristics of US children for product safety design. University of Mickigan, Ann Arbor, Michigan, LISA, Report No 011903-F, Oct 1975, 340 pp.
From an information retrieval viewpoint, microimage systems may compare favourably to traditional paper handling systems. However,
This report presents a comprehensive preliminary study of the strength of the US population of children, measured on 502 children between the ages of two
112
AppliedErgonomicsJune
1977
and ten years. The results consist of 33 isometric exertion measurements which include the torques developed around the wrist, elbow, shoulder, ankle, knee, hip, and trunk, together with the force of hand grip and several types of pinch. The results are presented in tabular form by age and as a graph of strength plotted against age for the right side of the body. Anthropometric measurements of the linkage lengths (distance between the joint centres of rotation) is presented in graphical and tabular form for the same subjects. A measurement system was conceived designed, fabricated, tested, and used to obtain these data efficiently. It uses a minicomputer to supervise experiments, collect data from several strain gauges simultaneously, implement an algorithm for the assignment of a numeric strength value to an exertion, and compact the data for final statistical analysis. A special test fixture, resembling a chair, uses a series of cantilevered beams to form an adjustable instrumented exoskeleton for the right side of the body. Careful attention was directed towards motivational factors in order to obtain maximum voluntary isometric exertions. All measurements were obtained with the subject seated in the test fixture so that the anatomic position was defined. A biomechanical computer model of a child was designed and has undergone preliminary testing. It allows the data for isometric strength to be used to estimate strength capability in various anatomic positions. 8.2.13 (70902)
Jorgensen, K., and Poulsen, E. Physiological problems in repetitive lifting with special reference to tolerance limits to the maximum lifting frequency. Ergonomics, Jan 1974, 17.1, 31-39. An experiment, including 79 measurements, on repetitive lifting of loads from floor to table has been performed with four female and four male subjects. For each subject: (1) the maximum load which could be lifted from floor to table height using a correct lifting technique, and (2) the maximum oxygen uptake (Vo~ max) were determined. From (1) relafive loads of approximately 10,25, 50 and 75% were calculated, and lifting with at least three different frequencies were performed with each relative weight. The lifting procedure lasted 20 min during which the oxygen uptake (Vo~) and the pulse rate were measured. The Vo2 max was determined for each relative load for each of the subjects. The maximum lifting frequencies for all subjects and relative loads were then plotted against relative burdens. Two curves, one for females and one for males, fitting the points
8.2.8 (70855) Hopkin, V.D. The provision and use of information on air traffic control displays. In: AGARD plans and developments for air traffic systems, Feb 1976, 12 pp; abstr in Scientific and Technical Aerospace Reports (Report No AGARD-CP-188). Several kinds of mismatch can occur at the man machine interface in air traffic control systems. One, often overlooked, concerns the provision of certain essential information in a form which is unusable. The traditional reliance on the man's strengths of adaptability and flexibility in order to match man and machine in the system is thwarted if he cannot use the information presented to him. Changes from qualitative to quantitative information, incomplete automation, and the apparent retention of decision making roles which in fact have been greatly modified, all pose problems of ensuring that the displayed information has been adapted successfully.
Factors affecting perceptual motor processes 8.2.9 (70864)
Ostberg, O. CRTs pose health problems for operators. International Journal of Occupational Health and Safety, Nov/Dec 1975, 44.6, 2 4 - 2 6 ; abstr in Electrical and Electronics Abstracts. Discusses hazards of cathode-ray tube display terminals in offices, ranging from discomfort to pain and extreme visual fatigue. Examines the interrelationships of the work environment which includes lighting and workplace layout, the work object (paperwork, computer display screen ere) and the worker.
what is good for the system is not always good for the system operator. Microimage viewing equipment is invariably introduced into offices as 'another job aid', without the necessary adjustments being made to the ambient illumination and workplaces. Furthermore the equipment itself and the microfilmed material may be of poor quality. Consequently, complaints of eye strain, visual discomfort, difficulties in reading and postural fatigue due to long term use of readers are commonplace. A literature review indicates that the 'microimage trade' is aware of these facts, but worker complaints are still numerous. Obviously, 'technical development' by itself does not create improved working conditions for the operator - Occupational Health regulations need to be developed. It must be realised that microimage reading is a demanding visual task that calls for purpose-designed workplaces, working environments, and job routines. The trend now discernible in large microimage systems is that persons above the age of 50 are visually handicapped' and unsuited for long term work at the readers. Such a trend indicates a serious inadequacy in present microimage systems. 8.2.11 (70886) Klein, K.E. et al Air operations and circadian performance rhythms. In: AGARD higher mental functioning in operational environments, Apr 1976, 12 pp; abstr in Scientific and Technical Aerospace Reports (Report No AGARD-CP-181 ; ISBN-92-835-1216-2). Experimental results and pertinent data from literature on circadian behavioural rhythms and their modifications through various factors are reviewed. Considered are operations of airerews round the clock and on transmeridian routes; some possibilities of appropriate scheduling are discussed.
Physiology, anthropometry and biomechanics
8.2.10 (70865) Ostberg, O. Review of visual strain, with special reference to micro-image reading. Paper presented at the International Micrographics Congress, Stockholm, Sweden, 28-31 Sap 1976, 10 pp.
8.2.12 (70900) Owings, C.L. et al Strength characteristics of US children for product safety design. University of Mickigan, Ann Arbor, Michigan, LISA, Report No 011903-F, Oct 1975, 340 pp.
From an information retrieval viewpoint, microimage systems may compare favourably to traditional paper handling systems. However,
This report presents a comprehensive preliminary study of the strength of the US population of children, measured on 502 children between the ages of two
112
AppliedErgonomicsJune
1977
and ten years. The results consist of 33 isometric exertion measurements which include the torques developed around the wrist, elbow, shoulder, ankle, knee, hip, and trunk, together with the force of hand grip and several types of pinch. The results are presented in tabular form by age and as a graph of strength plotted against age for the right side of the body. Anthropometric measurements of the linkage lengths (distance between the joint centres of rotation) is presented in graphical and tabular form for the same subjects. A measurement system was conceived designed, fabricated, tested, and used to obtain these data efficiently. It uses a minicomputer to supervise experiments, collect data from several strain gauges simultaneously, implement an algorithm for the assignment of a numeric strength value to an exertion, and compact the data for final statistical analysis. A special test fixture, resembling a chair, uses a series of cantilevered beams to form an adjustable instrumented exoskeleton for the right side of the body. Careful attention was directed towards motivational factors in order to obtain maximum voluntary isometric exertions. All measurements were obtained with the subject seated in the test fixture so that the anatomic position was defined. A biomechanical computer model of a child was designed and has undergone preliminary testing. It allows the data for isometric strength to be used to estimate strength capability in various anatomic positions. 8.2.13 (70902)
Jorgensen, K., and Poulsen, E. Physiological problems in repetitive lifting with special reference to tolerance limits to the maximum lifting frequency. Ergonomics, Jan 1974, 17.1, 31-39. An experiment, including 79 measurements, on repetitive lifting of loads from floor to table has been performed with four female and four male subjects. For each subject: (1) the maximum load which could be lifted from floor to table height using a correct lifting technique, and (2) the maximum oxygen uptake (Vo~ max) were determined. From (1) relafive loads of approximately 10,25, 50 and 75% were calculated, and lifting with at least three different frequencies were performed with each relative weight. The lifting procedure lasted 20 min during which the oxygen uptake (Vo~) and the pulse rate were measured. The Vo2 max was determined for each relative load for each of the subjects. The maximum lifting frequencies for all subjects and relative loads were then plotted against relative burdens. Two curves, one for females and one for males, fitting the points