The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform

Matthew Weston - One of the best experts on this subject based on the ideXlab platform.

  • Helsen, Gilis, and Weston (2006) do not err in questioning the Optical Error hypothesis as the only major account for explaining offside decision-making Errors
    Journal of Sports Sciences, 2007
    Co-Authors: Werner Helsen, Bart Gilis, Matthew Weston
    Abstract:

    Oudejans, Bakker, and Beek (2007) recognize several relevant aspects of offside judgements in association football in the paper by Helsen, Gilis, and Weston (2006). We agree that the existing knowledge base on offside assessment needs to be expanded for two reasons. First, from a theoretical point of view it is important to examine how assistant referees can learn to deal with the limitations of the human visual information processing system. Second, from a practical point of view it is relevant to understand better refereeing performances and to identify potential explanations for incorrect offside decisions that could impact on the final outcome of the game. Oudejans et al. (2007) believe we both misinterpreted the Optical Error hypothesis and that our data set was unsuited to test it. Below, we react to these comments.

  • Errors in judging offside in association football test of the Optical Error versus the perceptual flash lag hypothesis
    Journal of Sports Sciences, 2006
    Co-Authors: Werner Helsen, Bart Gilis, Matthew Weston
    Abstract:

    Abstract The objective of this study was to analyse the correctness of the offside judgements of the assistant referees during the final round of the FIFA 2002 World Cup. We also contrasted two hypotheses to explain the Errors in judging offside. The Optical Error hypothesis is based on an incorrect viewing angle, while the flash-lag hypothesis refers to perceptual Errors associated with the flash-lag effect (i.e. a moving object is perceived as spatially leading its real position at a discrete instant signalled by a briefly flashed stimulus). Across all 64 matches, 337 offsides were analysed using digital video technology. The Error percentage was 26.2%. During the first 15 min match period, there were significantly more Errors (38.5%) than during any other 15 min interval. As predicted by the flash-lag effect, we observed many more flag Errors (86.6%) than non-flag Errors (13.4%). Unlike the predictions of the Optical Error hypothesis, there was no significant difference between the correct and incorrec...

Hiroyuki Uenohara - One of the best experts on this subject based on the ideXlab platform.

E. Behrman - One of the best experts on this subject based on the ideXlab platform.

  • Reinforcement and backpropagation training for an Optical neural network using self-lensing effects
    IEEE Transactions on Neural Networks, 2000
    Co-Authors: A. Cruz-cabrera, E. Behrman, John Steck, Mingtao Yang, S. R. Skinner
    Abstract:

    The Optical bench training of an Optical feedforward neural network, developed by the authors, is presented. The network uses an Optical nonlinear material for neuron processing and a trainable applied Optical pattern as the network weights. The nonlinear material, with the applied weight pattern, modulates the phase front of a forward propagating information beam by dynamically altering the index of refraction profile of the material. To verify that the network can be trained in real time, six logic gates were trained using a reinforcement training paradigm. More importantly, to demonstrate Optical backpropagation, three gates were trained via Optical Error backpropagation. The output Error is Optically backpropagated, detected with a CCD camera, and the weight pattern is updated and stored on a computer. The obtained results lay the ground work for the implementation of multilayer neural networks that are trained using Optical Error backpropagation and are able to solve more complex problems.

  • IJCNN - Optical hardware backpropagation neural network
    IJCNN'99. International Joint Conference on Neural Networks. Proceedings (Cat. No.99CH36339), 1999
    Co-Authors: S. R. Skinner, A. Cruz-cabrera, John Steck, Mingtao Yang, E. Behrman
    Abstract:

    Optical Error backpropagation is experimentally demonstrated in a feedforward Optical neural network developed by the authors. To our knowledge, this is the first report of hardware backpropagation training in an Optical system. The network uses the trainable light steering behavior of an Optical nonlinear material to implement both neural processing and connectivity. The nonlinear material steers (by modulation of the phase front) a forward propagating information beam by dynamically altering the index of the refraction profile of the material via a stronger weighting beam. Effectively, the weight beam creates spatially varying lensing effects in the nonlinear material. These trainable effects steer the information beam to produce the correct output value at an Optical detector. A photorefractive crystal is used as a phase conjugate mirror to generate the backpropagated Optical Error. This backpropagated Optical Error is detected and used in a gradient descent algorithm to update the weighting beam profile in real time. Both computer simulation and experimental results are presented.

  • Backpropagation training of an Optical neural network
    Proceedings of the Seventh International Conference on Microelectronics for Neural Fuzzy and Bio-Inspired Systems, 1999
    Co-Authors: John Steck, A. Cruz-cabrera, S. R. Skinner, Mingtao Yang, E. Behrman
    Abstract:

    The experimental demonstration of Optical backpropagation in a feedforward Optical neural network, developed by the authors, is presented. To our knowledge, this is the first report of backpropagation training in an Optical system. The network uses a thermal nonlinear material as a neural processing layer and a photorefractive crystal as a phase conjugate mirror to backpropagate the Optical Error. The nonlinear material modulates the phase front of a forward propagating information beam by dynamically altering the index of the refraction profile of the material via a stronger weighting beam.

  • Optical hardware backpropagation neural network
    Proceedings of the International Joint Conference on Neural Networks, 1999
    Co-Authors: Sara Skinner, A. Cruz-cabrera, John Steck, E. Behrman
    Abstract:

    Optical Error backpropagation is experimentally demonstrated in a feedforward Optical neural network developed by the authors. To our knowledge, this is the first report of hardware backpropagation training in an Optical system. The network uses the trainable light steering behavior of an Optical nonlinear material to implement both neural processing and connectivity. The nonlinear material steers (by modulation of the phase front) a forward propagating information beam by dynamically altering the index of the refraction profile of the material via a stronger weighting beam. Effectively, the weight beam creates spatially varying lensing effects in the nonlinear material. These trainable effects steer the information beam to produce the correct output value at an Optical detector. A photorefractive crystal is used as a phase conjugate mirror to generate the backpropagated Optical Error. This backpropagated Optical Error is detected and used in a gradient descent algorithm to update the weighting beam profile in real time. Both computer simulation and experimental results are presented

Werner Helsen - One of the best experts on this subject based on the ideXlab platform.

  • Helsen, Gilis, and Weston (2006) do not err in questioning the Optical Error hypothesis as the only major account for explaining offside decision-making Errors
    Journal of Sports Sciences, 2007
    Co-Authors: Werner Helsen, Bart Gilis, Matthew Weston
    Abstract:

    Oudejans, Bakker, and Beek (2007) recognize several relevant aspects of offside judgements in association football in the paper by Helsen, Gilis, and Weston (2006). We agree that the existing knowledge base on offside assessment needs to be expanded for two reasons. First, from a theoretical point of view it is important to examine how assistant referees can learn to deal with the limitations of the human visual information processing system. Second, from a practical point of view it is relevant to understand better refereeing performances and to identify potential explanations for incorrect offside decisions that could impact on the final outcome of the game. Oudejans et al. (2007) believe we both misinterpreted the Optical Error hypothesis and that our data set was unsuited to test it. Below, we react to these comments.

  • Errors in judging offside in association football test of the Optical Error versus the perceptual flash lag hypothesis
    Journal of Sports Sciences, 2006
    Co-Authors: Werner Helsen, Bart Gilis, Matthew Weston
    Abstract:

    Abstract The objective of this study was to analyse the correctness of the offside judgements of the assistant referees during the final round of the FIFA 2002 World Cup. We also contrasted two hypotheses to explain the Errors in judging offside. The Optical Error hypothesis is based on an incorrect viewing angle, while the flash-lag hypothesis refers to perceptual Errors associated with the flash-lag effect (i.e. a moving object is perceived as spatially leading its real position at a discrete instant signalled by a briefly flashed stimulus). Across all 64 matches, 337 offsides were analysed using digital video technology. The Error percentage was 26.2%. During the first 15 min match period, there were significantly more Errors (38.5%) than during any other 15 min interval. As predicted by the flash-lag effect, we observed many more flag Errors (86.6%) than non-flag Errors (13.4%). Unlike the predictions of the Optical Error hypothesis, there was no significant difference between the correct and incorrec...

M. Suzuki - One of the best experts on this subject based on the ideXlab platform.