ABSTRACT
Genetic Algorithm is suitable for solving reliability allocation problem of software system. And also the operating efficiency and the solution quality are improved.
2 THE ANALYSIS OF NICHE GENETIC ALGORITHM
In biology, a niche refers to the organizational function or role in a specific environment. Species refer to the common features of organization. The organisms tend to live with each other with similar features and shapes [5]. The individual process of evolution is put in the same population repeatedly in traditional genetic algorithm. With the smoothly genetic exchanging, it is difficult for respective developing of the individual. So the diversity of population is reduced. To solve the problem, the individuals in the initial population are sorted by fitness value firstly. And the similar individuals evolve independently in the niche. The scale of sub-population is changing with the parent population. Let N be the scale of parent population, K be the scale of sub-population, we must have K = N(D), K is a function of D. It can be set firstly according to the characteristics of the problem. D is the variance of the individuals in a population while σ is a constant. When the diversity decreases, D decreases. When D is less than a threshold σ, the sub-population size will reduce to the minimum value 2 in order to stimulate the improvement of the diversity of the population.
