Search Results - (Author, Cooperation:S. Prentice)

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  1. 1
  2. 2
    Staff View
    Publication Date:
    2015-07-15
    Publisher:
    Nature Publishing Group (NPG)
    Print ISSN:
    0028-0836
    Electronic ISSN:
    1476-4687
    Topics:
    Biology
    Chemistry and Pharmacology
    Medicine
    Natural Sciences in General
    Physics
    Published by:
    Latest Papers from Table of Contents or Articles in Press
  3. 3
    Prentice, S. D. ; Patla, A. E. ; Stacey, D. A.
    Springer
    Published 1998
    Staff View
    ISSN:
    1432-1106
    Keywords:
    Key words Central pattern generator ; Locomotion ; Electromyography ; Neural network
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract  A neural network model has been developed to represent the shaping function of a central pattern generator (CPG) for human locomotion. The model was based on cadence and electromyographic data obtained from a single human subject who walked on a treadmill. The only input to the model was the fundamental timing of the gait cycle (stride rate) in the form of sine and cosine waveforms whose period was equal to the stride duration. These simple signals were then shaped into the respective muscle activation patterns of eight muscles of the lower limb and trunk. A network with a relatively small number of hidden units trained with back-propagation was able to produce an excellent representation of both the amplitude and timing characteristics of the EMGs over a range of walking speeds. The results are further discussed with respect to the dependence of some muscles upon sensory feedback and other inputs not explicitly presented to the model.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  4. 4
    Staff View
    ISSN:
    1432-1106
    Keywords:
    Key words Human locomotion ; Foot placement ; Path planning ; Obstacle avoidance ; Adaptive strategies
    Source:
    Springer Online Journal Archives 1860-2000
    Topics:
    Medicine
    Notes:
    Abstract  Our goal was to understand the bases for selection of alternate foot placement during locomotion when the normal landing area is undesirable. In this study, a light spot of different shapes and sizes simulated an undesirable landing area. Participants were required to avoid stepping on this spot under different time constraints. Alternate chosen foot placements were categorised into one of eight choices. Results showed that selection of alternate foot placement is systematic. There is a single dominant choice for each combination of light spot and normal landing spot. The dominant choice minimises the displacement of the foot from its normal landing spot (less than half a foot length). If several response choices satisfy this criterion, three selection strategies are used to guide foot placement: placing the foot in the plane of progression, choosing to take a longer step over a shorter step and selecting a medial rather than lateral foot placement. All these alternate foot-placement choices require minimal changes to the ongoing locomotor muscle activity, pose minimal threat to dynamic stability, allow for quick initiation of change in ongoing movement and ensure that the locomotor task runs without interruption. Thus, alternate foot-placement choices are dependent not only on visual input about the location, size and shape of the undesirable surface, but also on the relationship between the characteristics of the undesirable surface and the normal landing area.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses
  5. 5
    Allen, G. M. ; Wu, G. L. ; Prentice, S. A.

    New York, NY [u.a.] : Wiley-Blackwell
    Published 1992
    Staff View
    ISSN:
    0021-8995
    Keywords:
    Chemistry ; Polymer and Materials Science
    Source:
    Wiley InterScience Backfile Collection 1832-2000
    Topics:
    Chemistry and Pharmacology
    Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Physics
    Notes:
    Chemical and physical characteristics of sheet-molded compounds were investigated using infrared and mechanical spectroscopies. Fourier transform infrared spectroscopy with photoacoustic detection facilitated surface analysis for determination of composition, depth profile, and thermal exposure effects. Dynamic mechanical spectroscopy utilized torsion, tension, and flexure modes to evaluate temperature and frequency-dependent viscoelastic properties.
    Additional Material:
    10 Ill.
    Type of Medium:
    Electronic Resource
    URL:
    Articles: DFG German National Licenses