The number of solutions is not known Finding the right fitness function may

The number of solutions is not known finding the

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The number of solutions is not known. Finding the right fitness function may take many trials Convergence to at least one solution is not guaranteed. At its simplest, EC reduces to a trial-and-error search Domain knowledge and heuristics can improve the efficiency of the search Convergence may/often takes a very large number of generations. Depending on problem complexity, may be computationally intensive Remember the WYTIWYG principal: “What you test is what you get” Don´t tune algorithm performance on toy data and expect it to work with real data Ant Colony Optimization A probabilistic optimization technique for finding optimal paths through graphs. (Dorigo, Birattari, and Stutzle 2006) Basic Idea As a natural phenomenon, ants start to wander randomly looking for food. When they find food, they return to their colony while laying down pheromone trails. If other ants find such a path, they are likely not to keep travelling at random, but to instead follow the trail, returning and reinforcing it if they eventually find food.
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Cultural Algorithms Game-Theory Game Theory : agents make decisions based NOT on reactions to exogeneous events, but as strategic reactions to other agent’s actions. Often used in Economics and Political Science : The rules of the game state who can do what, and when they can do it. A player's strategy is a plan for actions in each possible situation in the game. Applications to many other fields. Rationality Assumption: All players are assumed rational All players know that all other players are rational. Definition: rationality means that actors are goal-oriented and calculating.
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Each player in a game tries to achieve the highest possible payoff for himself (at the expense of the other players). Each player calculates a strategy that best serves these interests., e.g., get as big a slice of the pie as possible. Each player’s rational decisions require anticipating competitor;s responses. Each player assesses the value of alternative courses of action and compares them before determining which course to take. Rationality does not mean: Selfish Short-run Sharing the same value system as other players or “ethical people” Originated with John von Neumann and Oskar Morgenstern in the 1940s Models "zero-sum games” von Neumann, John, and Oskar Morgenstern. Theory of Games and Economic Behavior. Second edition. Princeton, New Jersey: Princeton University Press, 1947 Assesses the cost versus the benefits of behaviors in interdependent decision- making situations among two or more actors 2-person game theory is considered complete; n-person game theory is incomplete The “tit for tat” strategy on conditional reciprocal cooperation can lead to cooperation when both actors understand the metagame and the game duration is indeterminate Players expectations are not perfect, so uncertainty is a necessary feature of games.
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  • Spring '15
  • StephenKaisler

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