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A biomechanical evaluation of staircase riser heights and tread depths during stair-climbing
a cost/performance analysis based on marketing data, a decision was made to produce this mouse design. These studies are briefly described along with the arguments used to make the decision, and a description of the ergonomics tools and features incorporated in this design are presented.
conducting each operation and the quality of the operation which was defined by the number of errors made by each user. The same evaluation was conducted for the new prototype to compare the validity of the new design. 19.3.20 (107384)
Wagenlehner, K. 19.3.18 (107367)
Parng, K.A., and Ellingstad, V. S. Touch tablet and touch input. In: Interface 87: Human Implications of Product Design, Proc 5th Symp Human Factors and lndust Des in Consumer Products, Rochester, New York, 13 --15 May 1987. Human Factors Soc, 1987, pp 3 2 7 - 3 3 6 . This paper summarises the results of five experiments conducted to evaluate the touch tablet as an input device to support human-computer communication. A number of factors unique to the use of the touch tablet have been systematically investigated. They are (1) two operation modes absolute vs relative, (2) two stylus modes -- finger r,s stylus, (3) three levels of tablet labelling, (4) two target sizes on the CRT display and touch tablet, (5) four control-display gains, and (6) six data insertion modes with different confirmation methods. Tasks performed by subjects in these experiments included: text editing, two-dimensional compensatory tracking, target/function selection, and alphanumeric data entry. 19.3.19 (107368)
Abedini, K. An ergonomically-improved remote control unit design. In: Interface 87: Human Implications of Product Design, Proc 5th Symp Human Factors and Ind Des in Consumer Products, Rochester, 13--15 May 1987. Human Factors Soc, 1987, pp 3 7 5 - 3 8 0 . Hand held and operated remote control units (RCUs) for televisions, video cassette recorders and many other electronic instruments are one of the most popular items used for userproduct interfacing in the present consumer market. Unfortunately, due to the rise in demand and ease of production, the design of these units totally disregards any human factors consideration. Thus users produce a long list of complaints when using such products. The purpose of this study was to point out the design considerations which should be emphasised for optimising the user interface. A prototype was then designed which included all such considerations and emphasised the ease of producability of such units. The study was conducted using surveys and subjective assessment in addition to objective performance measurements for both the time duration involved in
244
Applied Ergonomics
Mobile telephoning made easy. Features of modern user equipment gain in userfriendliness. Siemens Telcom Report, 1987, 10.4, 176- 178. Using a mobile telephone in a vehicle is totally different from using the office telephone. In a car there are many more activities to attend to besides communication. The mobile telephone is used in an environment with space and time constraints. The manufacturer must meet this challenge with suitably designed equipment and versatile operating procedures -- i e, the units have to be extremely compact and as easy to use as an office telephone. These requirements are met with a handset incorporating an optimised configuration of keypad and controls, and a menu-type man-machine interface.
retina stimulated, and ~b) whethel an3. line pattern from tile raster will b,: o! the critical retinal size:. Screens with 312 lines should be viewed from ~J distance that is at least four times the width of the screen. (2) l'he frequency with which the screen ~s refreshed" Many patients are sensitive at 50 per second, very few at 60 per second and above. (3) The presence of line interlace. This doubles the number of lines and effectively halves the refresh rate, If the screen is large enough and is viewed from a short distance the interlacing lines can form a highly epilcptogenic pattern. (4) The nature of the material displayed. (Flashing graphics are best avoided; closely-spaced text can be mildly epileptogenic. ) ( 5 ) The room illumination: dim lighting may be preferable. The nature of individual sensitivity also has to be considered in advising photosensitive patients.
Workplace and equipment design 19.3.23 (107437)
Mital, A., Fard, H.F., and Khaledi, H. 19.3,21 (106448)
Ostberg, O., Shahnavaz, H., and Stenberg, R. CRT flicker and scan-line direction.
Displays Tech and Applicat, 1987 8.2, 7 5 - 7 8 . 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. 19.3.22 (107423)
Wilkins, A.J. Photosensitive epilepsy and visual display units. In: Epilepsy in Young People, E. Ross, D. Chadwick and R. Crawford (Eds). John Wiley & Sons Ltd, Chichester, 1987, pp 147 - 155. About 4% of patients with epilepsy are liable to visually-induced seizures, A variety of visual stimuli can be responsible, ranging from flickering sunlight and striped shirts to intermittent cathode-ray tube displays such as television. The epileptogenic properties of intermittent cathode-ray tube displays are related to: (1) The size of the screen and the distance from which it is viewed, which together determine: (a) the area of
September1988
A biomechanical evaluation of staircase riser heights and tread depths during stair-climbing. Clin Biomcch, 1987, 2.3, 162 164. Several different staircase riser heights and tread depths were investigated in order to determine riser height and tread depth that minimised moments acting at the ankle, knee and hipjoints while walking upstairs. The results indicated that joint moments were minimised when the riser height was 102 ram. For the tread depth, least moments were obtained when the depth was 305 ram. 19.3.24 (107438)
Pauls, J. Are functional handrails within our grasp? In: Proc Env Des Res Assoc Conf, Ottawa, 29 M a y - 2 June, 1987, J. Harvey and D. Henning (Eds), Env Des Res Assoc, Washington, USA. 1987, pp 121- 127, Are functional handrails within our grasp? 'Yes!' should be the emphatic answer in relation to the user's manual grasp, the designer's mental grasp of a handrail's function, and society's ability to discover and apply knowledge related to handrail users' safety and comfort. To promote a discussion on these matters, a review is provided of research into functional criteria for handrails, including the important but often ignored criterion of graspability. Recent applications to building codes and standards are also noted. Such codes and standards may move towards more
conducting each operation and the quality of the operation which was defined by the number of errors made by each user. The same evaluation was conducted for the new prototype to compare the validity of the new design. 19.3.20 (107384)
Wagenlehner, K. 19.3.18 (107367)
Parng, K.A., and Ellingstad, V. S. Touch tablet and touch input. In: Interface 87: Human Implications of Product Design, Proc 5th Symp Human Factors and lndust Des in Consumer Products, Rochester, New York, 13 --15 May 1987. Human Factors Soc, 1987, pp 3 2 7 - 3 3 6 . This paper summarises the results of five experiments conducted to evaluate the touch tablet as an input device to support human-computer communication. A number of factors unique to the use of the touch tablet have been systematically investigated. They are (1) two operation modes absolute vs relative, (2) two stylus modes -- finger r,s stylus, (3) three levels of tablet labelling, (4) two target sizes on the CRT display and touch tablet, (5) four control-display gains, and (6) six data insertion modes with different confirmation methods. Tasks performed by subjects in these experiments included: text editing, two-dimensional compensatory tracking, target/function selection, and alphanumeric data entry. 19.3.19 (107368)
Abedini, K. An ergonomically-improved remote control unit design. In: Interface 87: Human Implications of Product Design, Proc 5th Symp Human Factors and Ind Des in Consumer Products, Rochester, 13--15 May 1987. Human Factors Soc, 1987, pp 3 7 5 - 3 8 0 . Hand held and operated remote control units (RCUs) for televisions, video cassette recorders and many other electronic instruments are one of the most popular items used for userproduct interfacing in the present consumer market. Unfortunately, due to the rise in demand and ease of production, the design of these units totally disregards any human factors consideration. Thus users produce a long list of complaints when using such products. The purpose of this study was to point out the design considerations which should be emphasised for optimising the user interface. A prototype was then designed which included all such considerations and emphasised the ease of producability of such units. The study was conducted using surveys and subjective assessment in addition to objective performance measurements for both the time duration involved in
244
Applied Ergonomics
Mobile telephoning made easy. Features of modern user equipment gain in userfriendliness. Siemens Telcom Report, 1987, 10.4, 176- 178. Using a mobile telephone in a vehicle is totally different from using the office telephone. In a car there are many more activities to attend to besides communication. The mobile telephone is used in an environment with space and time constraints. The manufacturer must meet this challenge with suitably designed equipment and versatile operating procedures -- i e, the units have to be extremely compact and as easy to use as an office telephone. These requirements are met with a handset incorporating an optimised configuration of keypad and controls, and a menu-type man-machine interface.
retina stimulated, and ~b) whethel an3. line pattern from tile raster will b,: o! the critical retinal size:. Screens with 312 lines should be viewed from ~J distance that is at least four times the width of the screen. (2) l'he frequency with which the screen ~s refreshed" Many patients are sensitive at 50 per second, very few at 60 per second and above. (3) The presence of line interlace. This doubles the number of lines and effectively halves the refresh rate, If the screen is large enough and is viewed from a short distance the interlacing lines can form a highly epilcptogenic pattern. (4) The nature of the material displayed. (Flashing graphics are best avoided; closely-spaced text can be mildly epileptogenic. ) ( 5 ) The room illumination: dim lighting may be preferable. The nature of individual sensitivity also has to be considered in advising photosensitive patients.
Workplace and equipment design 19.3.23 (107437)
Mital, A., Fard, H.F., and Khaledi, H. 19.3,21 (106448)
Ostberg, O., Shahnavaz, H., and Stenberg, R. CRT flicker and scan-line direction.
Displays Tech and Applicat, 1987 8.2, 7 5 - 7 8 . 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. 19.3.22 (107423)
Wilkins, A.J. Photosensitive epilepsy and visual display units. In: Epilepsy in Young People, E. Ross, D. Chadwick and R. Crawford (Eds). John Wiley & Sons Ltd, Chichester, 1987, pp 147 - 155. About 4% of patients with epilepsy are liable to visually-induced seizures, A variety of visual stimuli can be responsible, ranging from flickering sunlight and striped shirts to intermittent cathode-ray tube displays such as television. The epileptogenic properties of intermittent cathode-ray tube displays are related to: (1) The size of the screen and the distance from which it is viewed, which together determine: (a) the area of
September1988
A biomechanical evaluation of staircase riser heights and tread depths during stair-climbing. Clin Biomcch, 1987, 2.3, 162 164. Several different staircase riser heights and tread depths were investigated in order to determine riser height and tread depth that minimised moments acting at the ankle, knee and hipjoints while walking upstairs. The results indicated that joint moments were minimised when the riser height was 102 ram. For the tread depth, least moments were obtained when the depth was 305 ram. 19.3.24 (107438)
Pauls, J. Are functional handrails within our grasp? In: Proc Env Des Res Assoc Conf, Ottawa, 29 M a y - 2 June, 1987, J. Harvey and D. Henning (Eds), Env Des Res Assoc, Washington, USA. 1987, pp 121- 127, Are functional handrails within our grasp? 'Yes!' should be the emphatic answer in relation to the user's manual grasp, the designer's mental grasp of a handrail's function, and society's ability to discover and apply knowledge related to handrail users' safety and comfort. To promote a discussion on these matters, a review is provided of research into functional criteria for handrails, including the important but often ignored criterion of graspability. Recent applications to building codes and standards are also noted. Such codes and standards may move towards more