background: it has been claimed that by using different washing methods, the sperms can be separated according to size, motility, density, chromosomal content and surface markings and charge. these methods also reduce sperm chromatin deficiencies and screen the sperms before applying in assisted reproduction techniques. objective: this study compared simple density gradient methods and a combin...

In this paper, we propose a new descent method, called multiobjective memory gradient for finding Pareto critical points of optimization problem. The main thought in method is to select combination the current direction and past multi-step iterative information as search obtain stepsize by two types strategies. It proved that developed with suitable parameters always satisfies sufficient condit...