A nonlinear identification method for modelling the three-dimensional structure of velocity storage in the vestibulo-ocular reflex (VOR).
Item
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Title
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A nonlinear identification method for modelling the three-dimensional structure of velocity storage in the vestibulo-ocular reflex (VOR).
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Identifier
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AAI9108180
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identifier
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9108180
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Creator
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Sturm, Deborah Dorit.
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Contributor
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Adviser: Theodore Raphan
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Date
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1990
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Language
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English
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Publisher
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City University of New York.
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Subject
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Computer Science | Biology, Neuroscience | Engineering, Biomedical
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Abstract
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Velocity storage is present in vertical and roll components of compensatory eye movements if the head is oriented appropriately with regard to gravity (Raphan & Cohen, 1983; Matsuo & Cohen, 1984; Raphan & Cohen, 1987). To explain this, it has been postulated that gravity orients the eigenvectors of the three dimensional representation of velocity storage towards the space vertical (Raphan & Cohen, 1987; Sturm & Raphan, 1988). The thesis devised a computational procedure to identify the parameters of the system matrix from OKAN data. This procedure should help test this hypothesis in behavioral paradigms.;Velocity storage which is expressed by OKAN (Raphan et al, 1979), has been represented as a dynamical system, x{dollar}\sp\prime{dollar} = Hx, where x is a three dimensional vector representing the state of the system and H is the matrix containing the parameters that govern its dynamical behavior. Because of the assumption of linearity, the dynamical system was solved to give the pitch, roll, and yaw eye velocities in terms of the eigenvalues and eigenvectors of the system matrix. These parameters appear nonlinearly in the solution as a function of time. A nonlinear least squares fitting procedure (Marquardt, 1963) was adapted which compares data from cross-coupling experiments to the model outputs in order to identify the eigenvalues and eigenvectors of the system matrix. The eigenvalues and eigenvectors were determined using OKAN data from a monkey for a few tilt angles. When the parameters were set appropriately in the model, it closely predicted the cross-coupling effects.;Thus, a computational procedure has been developed which uses nonlinear identification techniques to identify parameters of a model of the three dimensional representation of velocity storage. This should be a useful tool in further theoretical and experimental studies on the vestibular ocular reflex.
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Type
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dissertation
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Source
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PQT Legacy CUNY.xlsx
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degree
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Ph.D.
