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Method of rules extraction for expert systems based on artificial neural networks. Shvarts Alexander Saratov State Technical University. Oil and gas industry. Intellectual systems. Medicine. and many others…. Transport. Technical diagnostics. Basis of intellectual systems. Rules
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Method of rules extraction for expert systems based on artificial neural networks Shvarts Alexander Saratov State Technical University
Oil and gas industry Intellectual systems Medicine and many others… Transport Technical diagnostics
Basis of intellectual systems • Rules • Decision trees • Regression analysis • Artificial neural networks • Multilayer perceptrons • Radial-basis functions networks • Kohonen self-organizing networks • Recurrent networks etc.
Disadvantages of expert systems based on artificial neural networks: Difficulties in explaining the decision making process Problems in validation “Missing exceptions” mistakes Existing problems X1 ? X2 X3 y1 X4 y2 X5 y3 X6 X7
Purpose of study: to introduce and develop new method, that could transform network structure into classification rules in order to • Easily validate expert system • Develop explaining module • Handle “missing exceptions” mistakes
Stages of research • Analysis of existing methods of rules extraction • Introducing new method with following characteristics: • Structure – multilayer perceptron • No network pruning and re-training • Testing the method on trained network
Wij,n X00 Wn,m X01 Attribute 0 H0 X02 C0 X10 H1 C1 X11 Attribute1 H2 C2 X12 X20 H3 Attribute2 X21 X22 Introduced method • Feedforward multilayer perceptron • One hidden layer • Hyperbolic tangent as the activation function of hidden layer • Sigmoid as the activation function of output layer • Input neurons are grouped into attributes
X1 H0 H1 Xi H2 Cm H3 XI Index of importance Weight index C0
X1 H0 Xi-1 H1 Attribute a Xi H2 Cm Xi+1 H3 XI Attributes calculations
Importance threshold where and - reliance coefficient
Combinations graph Attribute 1 Attribute 0 Attribute 7
Rules generation IF [Attribute 1]=[Value 4] AND [Attribute A]=[Value I] AND … AND [Attribute 0]=[Value 2] THEN [Class m] IF [Attribute 1]=[Value 5] AND [Attribute A]=[Value I] AND … AND [Attribute 0]=[Value 1] THEN [Class m] IF [Attribute 1]=[Value 6] AND [Attribute A]=[Value (I-1)] AND … AND [Attribute 0]=[Value 2] THEN [Class m]
Method application • Expert system for predicting arrhythmia, based on multilayer perceptron: • 15 inputs • 1 neuron in hidden layer • 2 classes • 92% fidelity
Experimental data Number of rules Reliance coefficient