ARTIFICIAL BEE COLONY ALGORITHM
The bee (Apis Mellifera) native to Europe and Africa is a social and domestic animal. Bees feed on nectar and pollens, where nectar is the prime source of energy and pollens act as supplements of proteins and other nutrients. The food source of larvae is pollens. Generally the bee colony consists of a single queen bee that is responsible for laying eggs, thousands of male bees called drones and thousands of worker bees, which are the sterile bees, and the young bee larvae called broods. Bees randomly searches for food source positions with good supply of nectar. Once a bee finds such a position, it goes back to the hive and communicates about the food source position by dancing in the comb. If the foraging bee finds the food source position close to hive, it performs a simple round dance and if the food source position is far from the hive, then it performs waggle dance. Waggle dance basically forms an eight like figure and the distance and the direction of the food source is indicated by this dance. The fastness of the dance conveys the distance. The inclination of the dance indicates the direction of the food source.
The artificial bee colony algorithm consists of 3 types of bees: the employed bee, onlooker bee and the scout bee. Scout bee is responsible for carrying out random searches in the environment. A bee who visits the food source visited by it previously is called an employed bee and the bee that waits in the beehive for decision making is called the onlooker bee. Both exploration and exploitation processes are carried out by all the three bees. In the ABC algorithm it is assumed that the colony consists of equal number of employed bees and onlooker bees and for every food source there is an employed bee in the hive. The bee whose food reservoir has been exhausted by other bees becomes a scout bee. The bee has the capability of memorizing the location of the food source once it has been discovered and then immediately starts exploiting it. The forage bee returns to the beehive with load of nectar from the source and then unloads the nectar to a food store. Following are the three options after unloading the nectar:
- If the food source is abandoned, then the bee becomes an uncommitted follower.
- If returning to the same food source, it dances and recruits other nest mates
- It continues to forage at the food source without recruiting other bees
The search cycle consists of three steps. In the beginning, some food sources are randomly selected by the bees and the amount of nectar is also determined. Then these bees return to the hive and share this information by performing the waggle dance. In second stage, each employed bee goes to the food source visited by her in previous cycle and then by means of visual information, chooses a new food source in the neighborhood. In the third stage, an onlooker bee visits the food source position depending on the nectar information shared by the employed bees. The food source with maximum nectar quantity is selected by the onlooker bee. After arriving at the selected food source, the onlooker bee, according to visual information, chooses a new source in the neighborhood of the selected food source. Once the food source is abandoned by the bee, a new food source is randomly selected by a scout and then the abandoned source is replaced by this new food source.
Department of Information Technology