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Published byBennett Liddle Modified over 2 years ago

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How many neurons are to be used? How the neurons are to be connected to form a network. Which learning algorithm to use? How to train the neural network? Training: Initialize the weights of the network and update the weights from a set of training examples

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Neuron w1w1 w2w2 wnwn Y...... x1x1 x2x2 x3x3 Input signals WeightOutput Signals

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The neuron computes the weighted sum of the input signals and compares the result with a threshold value of, T h If the net weighted input is less than the threshold the neuron output is –1. If the net weighted input is greater than or equal to the threshold, the neuron becomes activated and its output attains a value +1 (This type of activation function is called a sign function)

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w1 w2 Σ Th Threshold Linear Combiner Hard Limiter Y-output x1 x2 Step & sign activation function called hard limit functions. Single neuron with adjustable synaptic weight and a hard limiter.

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Step 1: Initialization Set the initial weights w 1,w 2,….w n and Threshold-Th Step 2: Activation Active the perceptron by applying inputs x 1 (p), x 2 (p)….. x n (p) and desired output Y d (p). Where p iteration, n number of inputs Step 3: Weight Training Update the weight of the perceptron. Step 4: Iteration Increase iteration p by one, go back to step 2 and repeat the process.

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EpochInputsY(d)Initial WeightOutput Y Error e Final Weight x1x2Ydw1w2w1w2 10000.3-0.1000.3-0.1 0100.3-0.1000.3-0.1 1000.3-0.110.2-0.1 1110.2-0.1010.30.0 20000.30.0000.30.0 0100.30.0000.30.0 1000.30.010.20.0 1110.20.0100.20.0 Threshold=0.2, Learning rate = 0.1

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EpochInputsY(d)Initial WeightOutput Y ErrorFinal Weight x1x2Ydw1w2w1w2 30000.20.0000.20.0 0100.20.0000.20.0 1000.20.010.10.0 1110.10.0010.20.1 40000.20.1000.20.1 0100.20.1000.20.1 1000.20.110.1 111 10 Threshold=0.2, Learning rate = 0.1

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EpochInputsY(d)Initial WeightOutput Y ErrorFinal Weight x1x2Ydw1W2w1w2 50000.1 00 010 00 100 00 111 10 Threshold=0.2, Learning rate = 0.1

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[Negnevitsky, 2001] M. Negnevitsky “ Artificial Intelligence: A guide to Intelligent Systems”, Pearson Education Limited, England, 2002. [Russel, 2003] S. Russell and P. Norvig Artificial Intelligence: A Modern Approach Prentice Hall, 2003, Second Edition [Patterson, 1990] D. W. Patterson, “Introduction to Artificial Intelligence and Expert Systems”, Prentice-Hall Inc., Englewood Cliffs, N.J, USA, 1990. [Minsky, 1974] M. Minsky “A Framework for Representing Knowledge”, MIT-AI Laboratory Memo 306, 1974.

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