Methods of Combining Neural Networks
 and Genetic Algorithms: A Tutorial
                   Talib S. Hussain
             ...
Brief Refresher


Neural Networks

     • Learning technique
     • Neurons with weighted connections
     • Learning thro...
Collaborative Combination Methods

Evolution of Connection Weights
     • GA optimises specific NN weights
     • GA used ...
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Methods of Combining Neural Networks and Genetic Algorithms

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Methods of Combining Neural Networks and Genetic Algorithms

  1. 1. Methods of Combining Neural Networks and Genetic Algorithms: A Tutorial Talib S. Hussain Queen’s University hussain@qucis.queensu.ca • Introduction to NNs and GAs • Approaches to Combining NNs and GAs Supportive: Applied to different stages of problem Collaborative: Applied concurrently to entire problem • Issues in Research and Applications Baldwin Effect: Learning guides evolution Generalisation: Must avoid over-specialising Genetic Encoding: Wide variety of methods
  2. 2. Brief Refresher Neural Networks • Learning technique • Neurons with weighted connections • Learning through weight changes • Represent a large class of functions • Highly biased search Genetic Algorithms • Optimisation technique • Populations of similar solutions • Survival of the fittest • Propagation by mutation and crossover • Weakly biased search
  3. 3. Collaborative Combination Methods Evolution of Connection Weights • GA optimises specific NN weights • GA used as the learning rule of the NN • Population of NNs with same topology but diff. weights • Pro: May converge faster than gradient descent • Less susceptible to local minima • Con: Highly inefficient in space and time Evolution of Architectures • GA optimises general NN structural parameters • GA applied in conjunction with neural learning • Population of NNs with different topologies • Pro: Not limited to fixed topology • Examines wide variety of solutions • Con: Convergence dependent upon genetic representation • May be highly inefficient in space and/or time Evolution of Learning Rules • GA optimises general NN structural and learning parameters • GA applied in conjunction with (variable) neural learning • Population of NNs with diff. topologies and learning methods • Pro: Not limited to fixed topology or learning rule • Applicable to wide range of problems • Con: Techniques are new, few and untested • Probably highly inefficient in time

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