A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MC...A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MCP） problem, and has been proven to be NP-complete that cannot be exactly solved in a polynomial time. The NPC problem is converted into a multiobjective optimization problem with constraints to be solved with a genetic algorithm. Based on the Pareto optimum, a constrained routing computation method is proposed to generate a set of nondominated optimal routes with the genetic algorithm mechanism. The convergence and time complexity of the novel algorithm is analyzed. Experimental results show that multiobjective evolution is highly responsive and competent for the Pareto optimum-based route selection. When this method is applied to a MPLS and metropolitan-area network, it will be capable of optimizing the transmission performance.展开更多
传统滚齿工装设计依赖经验积累和试错法,缺乏系统的分析手段,导致设计周期长、成本高。针对这一问题,本研究针对某盘类齿轮,利用有限元(finite element analysis, FEA)工具,开发出一套滚齿快换工装,从而提高滚齿工装的整体设计水平和力...传统滚齿工装设计依赖经验积累和试错法,缺乏系统的分析手段,导致设计周期长、成本高。针对这一问题,本研究针对某盘类齿轮,利用有限元(finite element analysis, FEA)工具,开发出一套滚齿快换工装,从而提高滚齿工装的整体设计水平和力学性能。首先基于圆柱渐开线斜齿轮滚齿加工原理完成工装结构设计,然后运用ANSYS Workbench软件进行仿真分析,分析结果表明工装的结构强度满足加工要求,但胀套上的等效应力值超出许用应力24%。为改善胀套的等效应力分布并提升其使用性能,采用基于遗传算法的多目标优化方法对其进行优化设计,优化后胀套在变形量与等效应力满足要求的前提下,其疲劳寿命由594.7次循环提升至6 666.3次循环。展开更多
基金the Natural Science Foundation of Anhui Province of China (050420212)the Excellent Youth Science and Technology Foundation of Anhui Province of China (04042069).
文摘A quality of service （QoS） or constraint-based routing selection needs to find a path subject to multiple constraints through a network. The problem of finding such a path is known as the multi-constrained path （MCP） problem, and has been proven to be NP-complete that cannot be exactly solved in a polynomial time. The NPC problem is converted into a multiobjective optimization problem with constraints to be solved with a genetic algorithm. Based on the Pareto optimum, a constrained routing computation method is proposed to generate a set of nondominated optimal routes with the genetic algorithm mechanism. The convergence and time complexity of the novel algorithm is analyzed. Experimental results show that multiobjective evolution is highly responsive and competent for the Pareto optimum-based route selection. When this method is applied to a MPLS and metropolitan-area network, it will be capable of optimizing the transmission performance.
