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Evolutionary Computation: Advanced Algorithms and Operators

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Presentation on theme: "Evolutionary Computation: Advanced Algorithms and Operators"— Presentation transcript:

1 Evolutionary Computation: Advanced Algorithms and Operators
Chapter 1-6 Jang, HaYoung March 28, 2011

2 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

3 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

4 Fitness Evaluation Optimization problem as follows:
Fitness evaluation function as follows: In binary coding,

5 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

6 Binary Strings N object variables x = (x1, x2, …, xn) into a binary string Decoding scheme Decoding function linearly maps the decoded integer value of the binary substring in the desired interval [ui, vi)

7 Gray Coded Strings Encoding binary string into Gray code
Decoding Gray code into binary string

8 Messy Coding Gene position and the corresponding bit values are coded in a string

9 Floating Point Coding Mantissa and exponent of a floating-point parameter Decoding

10 Coding for … Binary Variables Permutation problems Control problems
Presence or absence Permutation problems TSP Control problems Time or frequency dependent function of some control variables

11 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

12 Competitive Fitness Evaluation
Objective Fitness Is ‘absolute objective’ or complete ordering is always possible? Relative Fitness Direct comparison to some other solution either evolved or provided as a component of the environment Competitive Fitness Sensitive to the contents of the population

13 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

14 Model Selection Criteria
Minimal description length criterion Tradeoff between residual error Model complexity including a structure estimation term for the final model Number of bits necessary to encode the observations Number of bits needed to encode the parameters of the model

15 Model Selection Criteria
Akaike information criterion Approximation of the idealized Kullback-Leibler distance between the true data and the model Minimum message length Inferred estimates of the unknown parameters Data using an optimal code based on the data probability distribution

16 Minimum Descirption Legnth based Fitness Evaluation for Genetic Programming
Six multiplexor problem

17 Minimum Descirption Legnth based Fitness Evaluation for Genetic Programming

18 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

19 Contents Introduction to fitness evaluation
Encoding and decoding functions Competitive fitness evaluation Complexity-based fitness evaluation Multiobjective optimization Introduction to constraint-handling techniques

20 Search Space and Feasible and Infeasible Parts

21 Constraint Handling Techniques
Penalize infeasible individiuals Change the topology of the search space Repair infeasible solution Start with an initial population of feasible individuals Process solutions and constraints separately Locate feasible solutions


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