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Slip resistance versus surface roughness of deck and other underfoot surfaces in ships
Minitel keyboards. This ergonomics study is based upon the observed behaviour of several Minitel users who accomplished tasks with different Minitel keyboards in a realistic context of use. In fact, three complementary and still ongoing experiments have been realised; their main purpose is to produce recommendations in concrete form, by means of models which will be tested or further developed in the following experiment for the industrialisation of a new keyboard. The first experiment shows that the Minitel keyboard must keep the identity of the Minitel (size, aspect, telematic and telephone functions, ...) and approximate the use of a personal computer (user, dialogue, command syntax, arrangement of keyboard, key shape, centre-to-centre key spacing, ...). The manufacturers then built two models of keyboards respecting most of the recommendations from the first and second experiments. The last experiment focuses on the validation of those two models of keyboards and on the problem of the centre-to-centre key spacing differing from the 19 -+1 mm ISO standard. The analysis shows that the evolution of the Minitel is going towards 'a Videotex-PhoneComputer Terminal'.
22.6.28 (122176)
Van Meeteren, A. Characterisation of task performance with viewing instruments. J Optical Soc of AmericaA, 1990, 7.10, 2 0 1 6 - 2 0 2 3 , 22 refs. Recognition of one military vehicle of a group of six was investigated experimentally as a realistic observation task both for vision through image intensifiers and for thermal viewing devices. It is shown that recognition of real targets is visually equivalent to the detection of a circular disc of a certain size. The size of the equivalent disc is characteristic of the difficulty of the observation task. The image quality of viewing instruments can be related to the size of the disc that can just be detected. This measure of image quality includes resolution, low contrast, low luminance and noise effects. The effective range of viewing instruments is directly scaled to equivalent-disc size and can be taken as a practical measure of image quality.
22.6.29 (122179)
Sojourner, R.J., and Antin, J.F. The effects of a simulated head-up display speedometer on perceptual task performance. Human Factors, 1990, 32.3, 3 2 9 - 3 3 9 , 22 refs. This study compared the effects of simulated head-up display (HUD) and
dashboard-mounted digital speedometers on key perceptual driving tasks in a simulated driving environment. Subjects were 20 male and female volunteers ranging in age from 19 to 51 years. A videotape, taken from the driver's perspective, of a car travelling along a memorised route served as the test scene. While viewing the test scene, subjects performed tasks related to navigation, speed monitoring and salient cue detection. The simulated HUD speedometer produced generally superior performance on the experimental tasks; most important, it enabled subjects to respond significantly more quickly to the salient cues. Implications for the effects of HUDs on automobile safety are discussed.
22.6,30 (122186)
Nelson, T.M., and Niisson, T.H. Comparing headphone and speaker effects on simulated driving. Accident Analysis and Prevention, 1990, 22.6, 5 2 3 - 5 2 9 , 17 refs. Twelve persons drove for three hours in an automobile simulator while listening to music at sound level 63dB over stereo headphones during one session and from a dashboard speaker during another session. They were required to steer a mountain highway, maintain a certain indicated speed, change gears and respond to occasional hazards. Steering and speed control were dependent on visual cues. The need to change gear and the hazards were indicated by sound and vibration effects. With the headphones, the driver's average reaction time for the most complex task present changing gears - was about 0"33 s longer than with the speaker. The use of headphones did n o t delay the development of subjective fatigue.
kinetic coefficient of friction (UK1) was measured with a p r o t o t y p e apparatus, which simulates the movements o f a human foot and the forces applied to the underfoot surface during a sudden slip on the heel. The measured average UK1 s of the assessed floorings varied from 0.05 to 0.64. F o u r floorings were classified as very slip-resistant and one as slip-resistant. All the others were classified as slippery. The rough floorings were more shp-resistant than the smooth ones. The correlation between the arithmetical average roughness (Ra) and the average UK1 of the assessed surfaces was very significant (p < 0.001). When selecting deck and other underfoot surfaces and developing new flooring products, more attention should be paid to their surface texture. F r o m the slip resistance point of view, the adequate R a value was 7 - 9 / a m , so smoother surfaces should be avoided. A raisedpattern on floorings also improved the slip resistance compared with corresponding unpatterned floorings.
22.6.32 (122441)
Redfern, M.S., Mareotte, A., and Chaffin, D.B. A dynamic coefficient of friction measurement device for shoe/floor interface testing. J Safety Res, 1990, 21.2, 6 1 - 6 5 , 9 refs.
Gronqvist, R., Roine, J., Korhonen, E., and Rahikainen, A.
A dynamic coefficient of friction (COF) measurement device is described for use in recording shoe/ floor slip resistance. This device is computer-controlled and allows changes in the shoe/floor interface velocity and vertical force applied during a test. Different sole materials, floors and contaminants such as water or oil are testable. Repeatability tests of the device were conducted of four velocities (1, 2, 5 and 10 cm/s), three vertical force levels (5, 10 and 20 kg), and three floor conditions (dry, wet and oily). These tests showed that the COF measurements were highly repeatable with trial-to-trial standard deviations of from 0.5% to 4% of the means under all conditions.
Slip resistance versus surface roughness of deck and other underfoot surfaces in ships. J Occupat Accidents, 1990, 1 3 . 4 , 2 9 1 - 3 0 2 , 14 refs.
22.6.33 (122205) Lindqvist, B., Ahlberg, E., and
Workplace and equipment design 22.6.31 (122201)
The slip resistance of 13 deck and other underfoot surfaces commonly used in ships was assessed by measuring the kinetic coefficient of friction between these floorings, contaminated with glycerol, and three types of safety footwear. The floorings were used on decks, stairs and passages as well as in engine-rooms, kitchens and other indoor and o u t d o o r facilities. The
Skogsberg, L. Ergonomic tools in our time. Atlas Copco, Stockholm, 1986, 121 pp, 0 refs. The demands placed by end-users on the products supplied by tool manufacturers are constantly increasing and changing, not only towards high work output but also to conform to higher levels of safety,
Applied Ergonomics
December 1991
421
22.6.28 (122176)
Van Meeteren, A. Characterisation of task performance with viewing instruments. J Optical Soc of AmericaA, 1990, 7.10, 2 0 1 6 - 2 0 2 3 , 22 refs. Recognition of one military vehicle of a group of six was investigated experimentally as a realistic observation task both for vision through image intensifiers and for thermal viewing devices. It is shown that recognition of real targets is visually equivalent to the detection of a circular disc of a certain size. The size of the equivalent disc is characteristic of the difficulty of the observation task. The image quality of viewing instruments can be related to the size of the disc that can just be detected. This measure of image quality includes resolution, low contrast, low luminance and noise effects. The effective range of viewing instruments is directly scaled to equivalent-disc size and can be taken as a practical measure of image quality.
22.6.29 (122179)
Sojourner, R.J., and Antin, J.F. The effects of a simulated head-up display speedometer on perceptual task performance. Human Factors, 1990, 32.3, 3 2 9 - 3 3 9 , 22 refs. This study compared the effects of simulated head-up display (HUD) and
dashboard-mounted digital speedometers on key perceptual driving tasks in a simulated driving environment. Subjects were 20 male and female volunteers ranging in age from 19 to 51 years. A videotape, taken from the driver's perspective, of a car travelling along a memorised route served as the test scene. While viewing the test scene, subjects performed tasks related to navigation, speed monitoring and salient cue detection. The simulated HUD speedometer produced generally superior performance on the experimental tasks; most important, it enabled subjects to respond significantly more quickly to the salient cues. Implications for the effects of HUDs on automobile safety are discussed.
22.6,30 (122186)
Nelson, T.M., and Niisson, T.H. Comparing headphone and speaker effects on simulated driving. Accident Analysis and Prevention, 1990, 22.6, 5 2 3 - 5 2 9 , 17 refs. Twelve persons drove for three hours in an automobile simulator while listening to music at sound level 63dB over stereo headphones during one session and from a dashboard speaker during another session. They were required to steer a mountain highway, maintain a certain indicated speed, change gears and respond to occasional hazards. Steering and speed control were dependent on visual cues. The need to change gear and the hazards were indicated by sound and vibration effects. With the headphones, the driver's average reaction time for the most complex task present changing gears - was about 0"33 s longer than with the speaker. The use of headphones did n o t delay the development of subjective fatigue.
kinetic coefficient of friction (UK1) was measured with a p r o t o t y p e apparatus, which simulates the movements o f a human foot and the forces applied to the underfoot surface during a sudden slip on the heel. The measured average UK1 s of the assessed floorings varied from 0.05 to 0.64. F o u r floorings were classified as very slip-resistant and one as slip-resistant. All the others were classified as slippery. The rough floorings were more shp-resistant than the smooth ones. The correlation between the arithmetical average roughness (Ra) and the average UK1 of the assessed surfaces was very significant (p < 0.001). When selecting deck and other underfoot surfaces and developing new flooring products, more attention should be paid to their surface texture. F r o m the slip resistance point of view, the adequate R a value was 7 - 9 / a m , so smoother surfaces should be avoided. A raisedpattern on floorings also improved the slip resistance compared with corresponding unpatterned floorings.
22.6.32 (122441)
Redfern, M.S., Mareotte, A., and Chaffin, D.B. A dynamic coefficient of friction measurement device for shoe/floor interface testing. J Safety Res, 1990, 21.2, 6 1 - 6 5 , 9 refs.
Gronqvist, R., Roine, J., Korhonen, E., and Rahikainen, A.
A dynamic coefficient of friction (COF) measurement device is described for use in recording shoe/ floor slip resistance. This device is computer-controlled and allows changes in the shoe/floor interface velocity and vertical force applied during a test. Different sole materials, floors and contaminants such as water or oil are testable. Repeatability tests of the device were conducted of four velocities (1, 2, 5 and 10 cm/s), three vertical force levels (5, 10 and 20 kg), and three floor conditions (dry, wet and oily). These tests showed that the COF measurements were highly repeatable with trial-to-trial standard deviations of from 0.5% to 4% of the means under all conditions.
Slip resistance versus surface roughness of deck and other underfoot surfaces in ships. J Occupat Accidents, 1990, 1 3 . 4 , 2 9 1 - 3 0 2 , 14 refs.
22.6.33 (122205) Lindqvist, B., Ahlberg, E., and
Workplace and equipment design 22.6.31 (122201)
The slip resistance of 13 deck and other underfoot surfaces commonly used in ships was assessed by measuring the kinetic coefficient of friction between these floorings, contaminated with glycerol, and three types of safety footwear. The floorings were used on decks, stairs and passages as well as in engine-rooms, kitchens and other indoor and o u t d o o r facilities. The
Skogsberg, L. Ergonomic tools in our time. Atlas Copco, Stockholm, 1986, 121 pp, 0 refs. The demands placed by end-users on the products supplied by tool manufacturers are constantly increasing and changing, not only towards high work output but also to conform to higher levels of safety,
Applied Ergonomics
December 1991
421