Cuckoo Search Algorithm - Beyazıt Kölemen
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The document summarizes the Cuckoo Search algorithm, which is inspired by the brood parasitism behavior of some cuckoo species. It describes three key aspects of cuckoos' behavior that the algorithm is based on: 1) cuckoos lay their eggs in other birds' nests; 2) if the host bird discovers the foreign egg, it will throw it out or abandon the nest; 3) cuckoo eggs often hatch slightly earlier, allowing the cuckoo chick to evict the other eggs. The algorithm represents each solution as an "egg" in a nest - the aim is to use new solutions to replace inferior solutions. It operates according to three rules: each cuckoo lays one egg, the
Cuckoo Search Algorithm - Beyazıt Kölemen
- 1. Cuckoo SearchAlgorithm Beyazıt KÖLEMEN – 2017 Artifical Intelligence - HKU
- 2. Cuckoo Search Algorithm? A method of global optimization based on the behavior of cuckoos was proposed by Yang & Deb (2009). The original “Cuckoo Search (CS) Algorithm” is based on the idea of the following : • How cuckoos lay their eggs in the host nests. • How, if not detected and destroyed, the eggs are hatched to chicks by the hosts. • How a search algorithm based on such a scheme can be used to find the global optimum of a function.
- 3. Cuckoo Search Algorithm • The CS was inspired by the obligate brood parasitism of some cuckoo species by laying their eggs in the nests of host birds. • Some cuckoos have evolved in such a way that female parasitic cuckoos can imitate the colors and patterns of the eggs of a few chosen host species. • This reduces the probability of the eggs being abandoned and, therefore, increase their productivity .
- 4. Cuckoo Search Algorithm • If host birds discover the eggs are not their own, they will either throw them away or simply abandon their nests and build new ones. • Parasitic cuckoos often choose a nest where the host bird just laid its own eggs. • In general, the cuckoo eggs hatch slightly earlier than their host eggs.
- 5. Cuckoo Search Algorithm • If host birds discover the eggs are not their own, they will either throw them away or simply abandon their nests and build new ones. • Parasitic cuckoos often choose a nest where the host bird just laid its own eggs. • In general, the cuckoo eggs hatch slightly earlier than their host eggs.
- 7. Cuckoo Search Algorithm • Once the first cuckoo chick is hatched,his first instinct action is to evict the host eggs by blindly propelling the eggs out of the nest. • This action results in increasing the cuckoo chick’s share of food provided by its host bird . • Moreover, studies show that a cuckoo chick can imitate the call of host chicks to gain access to more feeding opportunity.
- 9. Cuckoo Search Algorithm • Each egg in a nest represents a solution, and a cuckoo egg represents a new solution. • The aim is to employ the new and potentially better solutions (cuckoos) to replace not-so- good solutions in the nests. • In the simplest form, each nest has one egg. • The algorithm can be extended to more complicated cases in which each nest has multiple eggs representing a set of solutions
- 10. Cuckoo Search Algorithm –Three Rules CS is based on three idealized rules: 1. Each cuckoo lays one egg at a time, and dumps its egg in a randomly chosen nest; 2. The best nests with high quality of eggs will carry over to the next generation; 3. The number of available hosts nests is fixed, and the egg laid by a cuckoo is discovered by the host bird with a probability.Discovering operate on some set of worst nests, and discovered solutions dumped from farther calculations.
- 11. Cuckoo Search Algorithm – STEP 1 Generate initial population of n host nests. (𝑎𝑖,𝑟𝑖) : a candidate for optimal parameters
- 12. Cuckoo Search Algorithm – STEP 2 Lay the egg (𝑎𝑘′,𝑏𝑘′) in the k nest. K nest is randomly selected. Cuckoo’s egg is very similar to host egg. Where 𝑎𝑘′=𝑎𝑘+𝑅𝑎𝑛𝑑𝑜𝑚𝑤𝑎𝑙𝑘(Lѐvy flight)𝑎𝑘 𝑟𝑘′=𝑟𝑘+𝑅𝑎𝑛𝑑𝑜𝑚𝑤𝑎𝑙𝑘(Lѐvy flight)𝑟𝑘 Lѐvy Flight: In nature, animals search for food in a random or quasi- random manner. Generally, the foraging path of an animal is effectively a random walk because the next move is based on both the current location/state and the transition probability to the next location. The chosen direction implicitly depends on a probability, which can be modeled mathematically.
- 13. Cuckoo Search Algorithm – STEP 3 Compare the fitness of cuckoo’s egg with the fitness of the host egg.
- 14. Cuckoo Search Algorithm – STEP 4 If the fitness of cuckoo’s egg is better than host egg, replace the egg in nest k by cuckoo’s egg.
- 15. Cuckoo Search Algorithm – STEP 5 If host bird notice it, the nest is abandoned and new one is built. (p <0.25) (to avoid local optimization) Iterate steps 2 to 5 until termination criterion satisfied
- 17. Pseude Code:
- 18. Application of CS •Engineering optimization problems •NP hard combinatorial optimization problems •Data fusion in wireless sensor networks •Nanoelectronic technology based operation-amplifier • (OP-AMP) •Train neural network •Manufacturing scheduling •Nurse scheduling problem
- 19. Thanks