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Sinusoidal and random whole-body vibration: comparative effects on visual performance
Journal of Sound and Vibration (1983) W(4), 589-592
HUMAN
RESPONSE
TO VIBRATION
ABSTRACTS Prepared by M. J. Griffin and J. Griffin, Human Factors Research Unit, Instituteof Sound and VibrationResearch, Universityof Southampton, Southampton SO9 5NH, England
T. Miwa, Y. Yonekawa and K. Kanada 1982 Journal of the Acoustical Society of America Slow vertex potentials evoked by whole-body impulsive vibrations in 214-221. recumbent men. (8 pages, 6 figures, 4 tables, 28 references) Authors’ Abstract. Characteristics of slow vertex responses evoked by whole-body vertical and horizontal impulsive vibrations of one cycle of a sinusoid were investigated in recumbent men. Fundamental frequencies were varied from 8 to 100 Hz. The p-p amplitudes and latencies of V potentials were determined as a function of vibration amplitude and fundamental frequency. The response patterns are similar to those evoked by optical and acoustic stimuli to human visual and auditory organs. The thresholds of the evoked potentials were determined by a cross-correlation technique and the perceptional thresholds measured for the same vibration. It is concluded that the perceptional thresholds can be estimated approximately from the thresholds of the evoked potentials, for example, by subtracting 14.5 dB from the thresholds of the evoked potentials for vertical vibrations and 10 dB from those for horizontal vibrations from 8 to 100 Hz. Topics: Complex Vibration (Impact, Impulses); Vibration Sense (Thresholds, Sensory
72,
Mechanisms); Physiological Effects (Central Nervous System); Non-vertical (Lying, x-); Limb Vibration ; Head Vibration ; Vibration Analysis Techniques.
Vibration
M. J. Moseley, C. H. Lewis and M. J. Griffin 1982. Aviation, Space and Environmental 53, 1000-1005. Sinusoidal and random whole-body vibration: comparative effects on visual performance. (6 pages, 4 figures, 4 tables, 15 references) Authors’ Abstract. An experimental comparison of the effect of whole-body sinusoidal and one-third octave-band random vibration on the performance of a display reading task is described. The findings indicate that one-third octave-band random vibration has significantly less effect on performance. Subsequent measurements of rotational head motion demonstrated that this finding may be due to differences in the velocity probability density distributions produced by the different motions. Subjects also performed the visual task during exposure to several broad-band random motions. Predicted error values were obtained by averaging the frequency weighted time histories of these motions. It was found that both r.m.s. and r.m.q. averaging procedures applied to the broad-band frequency weighted time histories gave accurate error predictions when compared with the measured error scores. Practical implications of the experimental findings and recommendations for future research are discussed. Topics: Perceptual Mechanisms (Vision); Complex Vibration (Random); Biodynamics
Medicine
(Transmissibility);
Vibration Analysis Techniques. 589
HUMAN
RESPONSE
TO VIBRATION
ABSTRACTS Prepared by M. J. Griffin and J. Griffin, Human Factors Research Unit, Instituteof Sound and VibrationResearch, Universityof Southampton, Southampton SO9 5NH, England
T. Miwa, Y. Yonekawa and K. Kanada 1982 Journal of the Acoustical Society of America Slow vertex potentials evoked by whole-body impulsive vibrations in 214-221. recumbent men. (8 pages, 6 figures, 4 tables, 28 references) Authors’ Abstract. Characteristics of slow vertex responses evoked by whole-body vertical and horizontal impulsive vibrations of one cycle of a sinusoid were investigated in recumbent men. Fundamental frequencies were varied from 8 to 100 Hz. The p-p amplitudes and latencies of V potentials were determined as a function of vibration amplitude and fundamental frequency. The response patterns are similar to those evoked by optical and acoustic stimuli to human visual and auditory organs. The thresholds of the evoked potentials were determined by a cross-correlation technique and the perceptional thresholds measured for the same vibration. It is concluded that the perceptional thresholds can be estimated approximately from the thresholds of the evoked potentials, for example, by subtracting 14.5 dB from the thresholds of the evoked potentials for vertical vibrations and 10 dB from those for horizontal vibrations from 8 to 100 Hz. Topics: Complex Vibration (Impact, Impulses); Vibration Sense (Thresholds, Sensory
72,
Mechanisms); Physiological Effects (Central Nervous System); Non-vertical (Lying, x-); Limb Vibration ; Head Vibration ; Vibration Analysis Techniques.
Vibration
M. J. Moseley, C. H. Lewis and M. J. Griffin 1982. Aviation, Space and Environmental 53, 1000-1005. Sinusoidal and random whole-body vibration: comparative effects on visual performance. (6 pages, 4 figures, 4 tables, 15 references) Authors’ Abstract. An experimental comparison of the effect of whole-body sinusoidal and one-third octave-band random vibration on the performance of a display reading task is described. The findings indicate that one-third octave-band random vibration has significantly less effect on performance. Subsequent measurements of rotational head motion demonstrated that this finding may be due to differences in the velocity probability density distributions produced by the different motions. Subjects also performed the visual task during exposure to several broad-band random motions. Predicted error values were obtained by averaging the frequency weighted time histories of these motions. It was found that both r.m.s. and r.m.q. averaging procedures applied to the broad-band frequency weighted time histories gave accurate error predictions when compared with the measured error scores. Practical implications of the experimental findings and recommendations for future research are discussed. Topics: Perceptual Mechanisms (Vision); Complex Vibration (Random); Biodynamics
Medicine
(Transmissibility);
Vibration Analysis Techniques. 589