软件定义网络(Software Defined Networking,SDN)由于其控制和转发分离的特性,在学术研究和工程上广泛应用于数据中心等领域.SDN体系结构中没有规定特定转发机制,而是通过更改控制模块或者开发具体的控制器App来实现.NOX是斯坦福大学在2...软件定义网络(Software Defined Networking,SDN)由于其控制和转发分离的特性,在学术研究和工程上广泛应用于数据中心等领域.SDN体系结构中没有规定特定转发机制,而是通过更改控制模块或者开发具体的控制器App来实现.NOX是斯坦福大学在2008年提出的第1种OpenFlow控制器,它基于OpenFlow协议提出了类似传统路由器OSPF协议的最短路径转发算法,即NOX路由模块(NOX routing module).该算法通过SDN系统控制链路收集全局交换机静态参数,并没有利用SDN系统的优势来获得交换机运行时的状态信息来提高转发性能.该文根据SDN集中控制以及控制器计算能力可扩展等特性,设计SDN结点、路径和流的评价体系,将各体系分支的评价指标作为交换机运行时的状态信息参数,在此基础上提出均衡算法.该Online算法具有自适应性和启发性,有效地提高了SDN在转发过程中(特别是针对大数据量)的运行效率.展开更多
研究一类在加工中广泛存在的孔群加工(Hole Group Machining,HGM)优化问题。孔群加工是多孔类零件加工中重要的工艺过程,研究其加工路线优化方法对于提高多孔类零件的加工效率、降低加工成本有重要意义。与传统的多孔加工点位优化不同,...研究一类在加工中广泛存在的孔群加工(Hole Group Machining,HGM)优化问题。孔群加工是多孔类零件加工中重要的工艺过程,研究其加工路线优化方法对于提高多孔类零件的加工效率、降低加工成本有重要意义。与传统的多孔加工点位优化不同,综合考虑了刀具选择、加工参数、加工次序及刀具路径的影响,以加工效率和成本为目标,建立优化问题数学模型。采用改进启发式算法克服了传统算法早熟、爬山能力弱,以及收敛性能不理想等缺点,并引入交互式多优先级控制,对加工工艺进行模糊多目标优化,提高了算法实用性。最后通过实例计算证明了算法的有效性。展开更多
A novel framework of hyper-heuristic algorithm was proposed to improve the adaption of evolutionary algorithms( EAs)in optimization. The algorithm could be changed during the evolutionary progress according to their p...A novel framework of hyper-heuristic algorithm was proposed to improve the adaption of evolutionary algorithms( EAs)in optimization. The algorithm could be changed during the evolutionary progress according to their performances. In addition,a large number of elite individuals were employed in the algorithm and the elite individuals helped algorithm achieve a better performance,while such number of elite individuals stagnated the global convergence in conventional single algorithm. The time complexity was analyzed to demonstrate the novel framework did not increase the time complexity. The simulation results indicate that the proposed framework outperforms any single algorithm that composes the framework.展开更多
文摘软件定义网络(Software Defined Networking,SDN)由于其控制和转发分离的特性,在学术研究和工程上广泛应用于数据中心等领域.SDN体系结构中没有规定特定转发机制,而是通过更改控制模块或者开发具体的控制器App来实现.NOX是斯坦福大学在2008年提出的第1种OpenFlow控制器,它基于OpenFlow协议提出了类似传统路由器OSPF协议的最短路径转发算法,即NOX路由模块(NOX routing module).该算法通过SDN系统控制链路收集全局交换机静态参数,并没有利用SDN系统的优势来获得交换机运行时的状态信息来提高转发性能.该文根据SDN集中控制以及控制器计算能力可扩展等特性,设计SDN结点、路径和流的评价体系,将各体系分支的评价指标作为交换机运行时的状态信息参数,在此基础上提出均衡算法.该Online算法具有自适应性和启发性,有效地提高了SDN在转发过程中(特别是针对大数据量)的运行效率.
文摘研究一类在加工中广泛存在的孔群加工(Hole Group Machining,HGM)优化问题。孔群加工是多孔类零件加工中重要的工艺过程,研究其加工路线优化方法对于提高多孔类零件的加工效率、降低加工成本有重要意义。与传统的多孔加工点位优化不同,综合考虑了刀具选择、加工参数、加工次序及刀具路径的影响,以加工效率和成本为目标,建立优化问题数学模型。采用改进启发式算法克服了传统算法早熟、爬山能力弱,以及收敛性能不理想等缺点,并引入交互式多优先级控制,对加工工艺进行模糊多目标优化,提高了算法实用性。最后通过实例计算证明了算法的有效性。
基金National Natural Science Foundations of China(Nos.70871091,61075064,61034004,61005090)Program for New Century Excellent Talents in University of Ministry of Education of ChinaPh.D.Programs Foundation of Ministry of Education of China(No.20100072110038)
文摘A novel framework of hyper-heuristic algorithm was proposed to improve the adaption of evolutionary algorithms( EAs)in optimization. The algorithm could be changed during the evolutionary progress according to their performances. In addition,a large number of elite individuals were employed in the algorithm and the elite individuals helped algorithm achieve a better performance,while such number of elite individuals stagnated the global convergence in conventional single algorithm. The time complexity was analyzed to demonstrate the novel framework did not increase the time complexity. The simulation results indicate that the proposed framework outperforms any single algorithm that composes the framework.
