Suchergebnisse

Metafacts are those factors in society which set human values and thus become forces that profoundly influence behavior. Study of the principles by which metafacts may be generated and controlled appears to be urgently needed for the orderly development of future technological-sociological interfaces.

The existing state of the art for handling human performance under transient heat stress has been reviewed. It was concluded that it is necessary to develop a new methodology based on "micro-performance" measurements to assess severe localized transient heat stresses relevant to contemporary flight problems. The test procedure proposed is based on the rationale that a primary task, with difficulty that can be varied according to subject error in order to maintain a relatively constant subject performance level, can be used as a measure of the moment-to-moment perceptual load. In addition to the primary task, secondary tasks are suggested to help simulate problems in decision-making and verbal communication.

Human operator performance in continuous pursuit tracking when the stimulus either disappeared prior to the appropriate response time or appeared subsequently to that time was investigated. Tracking was one-dimensional, the stimulus appeared to vary randomly, and feedback of results wasn't provided. The stimulus, consisting of the sum of three low-frequency sine waves, appeared on recording paper tape, moving at 1.0 cm/sec. Masks hid the display in steps up to 1.0 secs, before or 0.5 secs. after the position of a manually-controlled pointer. Timing performance was measured by the peaks of cross-correlations of stimulus/response data pairs which had been successively shifted in time. Tracking performance was measured by RMS error. Timing was increasingly too early for advanced displays but followed closely the actual appearance time of delayed displays. RMS tracking error increased with increasingly advanced and delayed displays. Practice effects were negligible.

This experiment evaluated the independent effects of error magnification and field of view on compensatory tracking performance. Both display and optical magnification were investigated. In general, the results demonstrated that: (1) the facilitative effect on performance of display magnification was primarily due to the concomitant field of view reduction and not magnification per se; (2) optical magnification facilitated performance but subsequent display gain increases had no further affect; (3) regardless of visual mode employed, optimum performance levels on a complex trajectory converged at approximately the same field of view. In was suggested that increasing the optical gain or decreasing the field of view resulted in subjects reducing their reaction times to target movements. No evidence was found which indicated that magnification facilitated visual perception.

Psychometric functions of pulse rate (PR) and pulse width (PW) from electrocutaneous stimuli were determined using the method of comparative judgments. The study revealed that changes in PR were more easily detected than changes in PW, as measured by the percent of just noticeable difference (jnd). The PR jnd data from test subjects indicated that maximum frequency discrimination occurred near 20 pulses per second. Using the PR and PW psychometric curves, compensatory transfer functions can be determined which will improve the efficacy of sensory communication systems based on electrocutaneous stimulation.

An experiment was performed on the NOTS-UCLA heavy inertia tracking simulator to assess effects of display magnification, proprioceptive cues, displacement aiding, trajectory characteristics and trajectory direction on tracking performance. Particular attention was paid to interactions among these variables. The results showed that: (1) 5x magnification significantly decreased tracking error compared to tracking without magnification; (2) proprioceptive cues related to both azimuth and elevation significantly improved performance; (3) velocity plus displacement-aiding control dynamics (time constant = 0.1 sec) produced significantly lower error scores than unaided velocity control dynamics (time constant = 0.0 sec); (4) since no crossover tendencies were found, the effects of the varables appear to be independent.

Introduction / Brian J. Rouleau -- Early life -- From third mate to first mate -- Twice around Cape Horn -- Master in steam and sail -- Commanding the Kitsap -- The wreck of the Julia H. Ray -- Whalers in the Arctic -- Alaska and the salmon trade -- A married man -- Trouble on the Yangtze -- A court case -- To the Klondike for gold -- San Francisco earthquake, Yokohama typhoon -- The Peruvian oilfields -- Hurricane in the tropics -- War in Europe -- Arrested for murder -- A new owner for the H. K. Hall -- A run to Japan in a shipping board steamer -- A lost rudder -- Carrying coal to Peru -- An auto accident -- A Finnish sailor bests five Peruvian police -- Saving the charter of the Ella A. -- The last voyage of the schooner Ella A. -- Bound for home -- Afterword / David Hull -- Notes -- Glossary of nautical terms