Abstract: The pheromone trails in ACO are used to reflect the ants' search experience, and the ants exploit them to probabilistically construct solutions to the problem, so the quality of the pheromone is crucial to the success of ACO.The main factors affecting the duality of the pheromone include the policy of updating the pheromone and the duality of the constructed solutions. In order to improve the constructed solutions, this paper presented a method to analyze the invalid components of the constructed solution, and then repaired the invalid components with immunity operator. When the pheromone density on the components is updated according to the improved solution, they will more exactly reflect the character of high quality solution, so it will speed the positive feedback procedure. The results show that the use of immunity repairing helps to find competitive solutions in a relatively short time.

Key words: Ant colony optimisation, Policy of pheromone update, Deceptive problem