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7주 강의 Machine Evolution.

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Presentation on theme: "7주 강의 Machine Evolution."— Presentation transcript:

1 7주 강의 Machine Evolution

2 Neural Networks Some aspects of learning in biological systems
차의영 교수님 강의에서 배울 것

3 Evolutions Generations of descendants Search processes
Production of descendants changed from their parents Selective survival Search processes Searching for high peaks in the hyperspace

4 Applications Function optimization Solving specific problems
The maximum of a function ::: John Holland Solving specific problems Control reactive agents Classifier systems Genetic programming

5 A program expressed as a tree

6 A robot to follow the wall around forever
Primitive functions : AND, OR, NOT, IF Boolean functions AND(x,y) = 0 if x = 0; else y OR(x,y) = 1 if x = 1; else y NOT(x) = 0 if x = 1; else 1 IF(x,y,Z) = y if x = 1; else z Actions North, east, south, west

7 A robot to follow the wall around forever
All of the action functions have their indicated effects unless the robot attempts to move into the wall Sensory inputs ::: n, ne, e, se, s , sw, w, nw 만약 함수의 수행결과가 값이 없으면 중지

8 A robot in a Grid World

9 A wall following program

10 The GP process Generation 0 (0세대): start with a population of random programs with functions, constants, and sensory inputs 5000 random programs Final : Generation 62  60 steps 동안 벽에 있는 방을 방문한 횟수로 평가  32 cells이면 perfects; 10곳에서 출발하여 fitness 측정

11 Generation of populations I
(i+1)th generation 10%는 i-the generation에서 copy  5000 populations에서 무작위로 7개를 선택하여 가장 우수한 것을 선택 (tournament selection) 90%는 앞의 방법으로 두 프로그램(a mother, a father)을 선택하여, 무작위로 선정한 father의 subtree를 mother의 subtree에 넣는다 (crossover)

12 Crossover

13 Generation of populations II
Mutation : 1%를 tournament로 선정  무작위로 선택한 subtree를 제거하고, 1세대에서 개체를 생성하는 방법으로 만들어서 끼워넣는다

14 Evolving a wall-following robot
개별 프로그램의 예 (AND (sw) (ne)) (with fitness 0) (OR (e) (west) (with fitness 5(?)) the best one ::: fitness = 92 (어떤 때)

15 The most fit individual in generation 0

16 The most fit individuals in generation 2

17 The most fit individuals in generation 6

18 The most fit individuals in generation 10

19 Fitness as a function of generation number

20 숙제 Specify fitness functions for use in evolving agents that
Control an elevator Control stop lights on a city main street Determine what the words genotype and phenotype in evolutionary theory? Why do you think mutation might or might no be helpful in evolutionary processes that use crossover?


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