As perspiration increases, more sweat glands begin to conduct electricity in a given area of skin. The reason for using conductance instead of resistance lies in the understood model for skin conductivity. Responses are also screened by amplitude, a minimum response amplitude of 0.02 micro Siemens may be required. The abbreviations SR and NSR are correct terms for use in publications. Later than this will be considered a non-specific response (NSR) also called a spontaneous response (SR) not a stimulus elicited response. For this reason studies which look at discrete responses apply a time window in the analysis such that responses are only accepted if the onset lies between 0.8 (or 1) second and usually 4 seconds after the stimulus. There is a delay between stimulus and SC response, usually considered to be a minimum of 0.8 seconds. A classic SCR (SC Response) to a discrete stimulus is shown in the red trace, with its characteristic onset slope, rise time, peak, and exponential decay, sometimes measured as 'half recovery time'. See Martin & Venables, Handbook of Psychophysiology, 1979. The site used on the feet (rarely) is at the heel. Two sites on the hand may be used, medial phalange of the fingers, or palm. Sensitive response to thoughts is only found at two places on the body, the hand and foot. At low levels, this happens all the time, as the mind experiences thoughts and emotion. It is based in the primitive 'fight or flight' response, whereby the body prepares itself for the exertion needed to deal with a perceived threat by increasing sweat activity to cool itself. Skin Conductance is also known as Galvanic Skin Response (GSR) or Electrodermal activity (EDA), but Skin Conductance is the currently used term. SC response (SCR) provides an indication of arousal. Skin conductance (SC) is normally measured with 8mm diameter silver/silver chloride electrodes positioned on the medial phalanx of the index and middle fingers held in position by double sided sticky electrode collars. The system accommodates a wide variety of experiment including showing pictures, playing sounds, and recording synchronized video in computer file. The PsychLab SC instrument provides for high resolution skin conductance measurement to produce publishable data. It was therefore concluded that the kinematic noise caused by skin movement artifact during upper-arm internal-external rotation does not follow a sinusoidal pattern and cannot be effectively eliminated by an optimization model.Designing an experiment with specific responses The soft tissue artifact from human subjects and the simulated soft tissue artifact from artificial sinusoidal noise were demonstrated to be considerably different. The result from both human and mechanical arm kinematic data demonstrates that soft tissue artifact can be reduced by an optimization model, although this error cannot be successfully eliminated. All data were processed by an optimization model. Artificial sinusoidal noise was then added to the recorded mechanical arm data to simulate soft tissue artifact. A mechanical arm, with the same marker set attached, replicated the tasks human subjects performed. Four subjects were captured performing upper-arm internal-external rotation with retro-reflective marker sets attached to their upper extremities. The purpose of this study was to quantify the effect of soft tissue artifact during three-dimensional motion capture and assess the effectiveness of an optimization method to reduce this effect.
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