Welcome!
To use the personalized features of this site, please log in or register.
If you have forgotten your username or password, we can help.
My Menu
Saved Items

Self-selected modular recurrent neural networks with postural and inertial subnetworks applied to complex movements

Jean-Philippe Draye1, Jack M. Winters2 and Guy Cheron3

(1)  Avaya Belgium sa/nv, Waterloo Office Park, Building K, Drève Richelle 161, 1410 Waterloo, Belgium, BE
(2)  Biomedical Engineering Department, Catholic University of America, Washington, D.C., USA, US
(3)  Laboratory of Biomechanics, University of Brussels, Brussels, Belgium, BE
Abstract.   It has been shown that dynamic recurrent neural networks are successful in identifying the complex mapping relationship between full-wave-rectified electromyographic (EMG) signals and limb trajectories during complex movements. These connectionist models include two types of adaptive parameters: the interconnection weights between the units and the time constants associated to each neuron-like unit; they are governed by continuous-time equations. Due to their internal structure, these models are particularly appropriate to solve dynamical tasks (with time-varying input and output signals). We show in this paper that the introduction of a modular organization dedicated to different aspects of the dynamical mapping including privileged communication channels can refine the architecture of these recurrent networks. We first divide the initial individual network into two communicating subnetworks. These two modules receive the same EMG signals as input but are involved in different identification tasks related to position and acceleration. We then show that the introduction of an artificial distance in the model (using a Gaussian modulation factor of weights) induces a reduced modular architecture based on a self-elimination of null synaptic weights. Moreover, this self-selected reduced model based on two subnetworks performs the identification task better than the original single network while using fewer free parameters (better learning curve and better identification quality). We also show that this modular network exhibits several features that can be considered as biologically plausible after the learning process: self-selection of a specific inhibitory communicating path between both subnetworks after the learning process, appearance of tonic and phasic neurons, and coherent distribution of the values of the time constants within each subnetwork.
Received: 17 September 2001 / Accepted in revised form: 15 January 2002

Fulltext Preview (Small, Large)
Image of the first page of the fulltext


Export this article
Export this article as RIS | Text
 
Referenced by
1 newer article

  1. Winters, J.M. (2003) Wearable sensors and telerehabilitation. IEEE Engineering in Medicine and Biology Magazine 22(3)
    [CrossRef]
Remote Address: 38.107.191.113 • Server: mpweb02
HTTP User Agent: CCBot/1.0 (+http://www.commoncrawl.org/bot.html)