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Unformatted text preview: Kyle Harbison CM 1090 Galvanic Vestibular Stimulation BE35001 Biocontrols May 1, 2009 I certify that I have solved this problem working independently and without consulting anyone except the instructor of this course. Name:_________________________ Signature:_________________________ i Project Setup Given When electrodes are attached to the mastoid bones (directly behind the ears) and current pulses are applied, a person will sway forward and backward. This situation is known as human postural sway in response to galvanic vestibular stimulation (GVS). It has been found that the transfer function relating the applied current (in amps) to the subject’s angle of sway (in radians) with respect to the vertical is given by: gG¡¢ £G¡¢ ¤ uU¥GU¦¡ § ¨¢© ªU«¬ G¡ § ¨¢G ¡ ¨U® § U ¯¡ ¨U® § ¨¢ Find 1 Initially, ignore the © ªU«¬ term in the numerator. Determine an expression for Θ (t) when the applied current is 1mA (i.e., i(t)=1 mA u(t)). 2 Plot Θ (t) as a function of time. What is the maximum sway (in degrees) that occurs in response to this current? 3 Based on your answer to Part 1, can a 2 nd order approximation be used to model this system? Use answers to Parts 1 and 2 to determine ° ± ² ° ³ ² ° ¬ ´µ¶ ·¸¹©º»¼½½¾ 4 Now, include the © ªU«¬ term in the numerator. If the applied current remains the same as in Part 1, determine an expression for Θ (t). What effect does the © ªU«¬ term have on the response? What is the physiological significance of this term? 5 Write an expression for i(t) and I(s) if the applied current is changed to a 2.5 mA pulse of 500 msec duration. 6 Determine an expression for Θ (t) when the applied current is changed to the pulse described in Part 5. 7 Replot Θ (t) as a function of time. What is the maximum sway (in degrees) that occurs in response to this current pulse? To Turn In Detailed answers to each part, appropriately labeled graphs, and worksheets from computer applications that were used to obtain your answers. ii Table of Contents Project Setup………………………………………………………………………………………………..i Table of Contents…………………………………………………..……………………………………….ii Part One………………………………………………………………….………………………………….1 Part Two……………………………………………………………………………….……………………3 Figure 1 Θ(t) Resulting From Unshifted Step Input……………………………………….3 Part Three…………………………………………………………………………………………………...4 Part Three…………………………………………………………………………………………………....
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 Spring '10
 WEINER
 Partial fractions in complex analysis, θ, Galvanic Vestibular Stimulation, step input, maximum sway, Nonshifted Step Input

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