Because of explosive growth in Internet traffic and high complexity of heterogeneous networks, improving the routing and wavelength assignment （RWA） algorithm in underlying optical networks has become very important...Because of explosive growth in Internet traffic and high complexity of heterogeneous networks, improving the routing and wavelength assignment （RWA） algorithm in underlying optical networks has become very important. Where there are multiple links between different the node pairs, a traditional wavelength-assignment algorithm may be invalid for a wavelength-switched optical networks （WSON） that has directional blocking constraints. Also, impairments in network nodes and subsequent degradation of optical signals may cause modulation failure in the optical network. In this paper, we propose an RWA algorithm based on a novel evaluation model for a WSQN that has multiple constraints. The algorithm includes comprehensive evaluation model （CEM） and directional blocking constraint RWA based on CEM （DB-RWA）. Diverse constraints are abstracted into various constraint conditions in order to better assign routing and wavelength. We propose using the novel CEM to optimize routing according to an assessed value of constraints on transmission performance. This eliminates the effects of physical transmission impairments in a WSON. DB-RWA based on CEM abstracts directional blocking conditions in multiple links between network nodes into directional blocking constraints. It also satisfies rigorous network specifications and provides flexibility, scalability, and first-fit rate for the backbone, especially in multiple links between WSON nodes.展开更多
针对机械式穴播器装配线上在制品(Work In Process,WIP)主要依靠管理人员经验进行定性控制的问题,采用多点控制的方法对装配线上在制品进行定量优化。首先运用约束理论(Theory Of Constraint,TOC)结合推、拉两种生产方式对装配线进行分...针对机械式穴播器装配线上在制品(Work In Process,WIP)主要依靠管理人员经验进行定性控制的问题,采用多点控制的方法对装配线上在制品进行定量优化。首先运用约束理论(Theory Of Constraint,TOC)结合推、拉两种生产方式对装配线进行分段研究,在分段节点设立瓶颈缓冲区、并联缓冲区和风险缓冲区;然后根据工位故障持续时间与物料消耗速度计算出缓冲区最优容量,得出机械式穴播器装配线在制品多点控制优化方案。通过对某企业机械式穴播器装配系统进行Flex Sim仿真,验证了方案的可行性。展开更多
基金supported in part by 973 Program(2010CB328204)NSFC project(60932004)RFDP Project(20090005110013)
文摘Because of explosive growth in Internet traffic and high complexity of heterogeneous networks, improving the routing and wavelength assignment （RWA） algorithm in underlying optical networks has become very important. Where there are multiple links between different the node pairs, a traditional wavelength-assignment algorithm may be invalid for a wavelength-switched optical networks （WSON） that has directional blocking constraints. Also, impairments in network nodes and subsequent degradation of optical signals may cause modulation failure in the optical network. In this paper, we propose an RWA algorithm based on a novel evaluation model for a WSQN that has multiple constraints. The algorithm includes comprehensive evaluation model （CEM） and directional blocking constraint RWA based on CEM （DB-RWA）. Diverse constraints are abstracted into various constraint conditions in order to better assign routing and wavelength. We propose using the novel CEM to optimize routing according to an assessed value of constraints on transmission performance. This eliminates the effects of physical transmission impairments in a WSON. DB-RWA based on CEM abstracts directional blocking conditions in multiple links between network nodes into directional blocking constraints. It also satisfies rigorous network specifications and provides flexibility, scalability, and first-fit rate for the backbone, especially in multiple links between WSON nodes.
文摘针对机械式穴播器装配线上在制品(Work In Process,WIP)主要依靠管理人员经验进行定性控制的问题,采用多点控制的方法对装配线上在制品进行定量优化。首先运用约束理论(Theory Of Constraint,TOC)结合推、拉两种生产方式对装配线进行分段研究,在分段节点设立瓶颈缓冲区、并联缓冲区和风险缓冲区;然后根据工位故障持续时间与物料消耗速度计算出缓冲区最优容量,得出机械式穴播器装配线在制品多点控制优化方案。通过对某企业机械式穴播器装配系统进行Flex Sim仿真,验证了方案的可行性。
