In the environment of customization, disturbances such as rush orders and material shortages often occur in the manufacturing system, so rescheduling is necessary for the manufacturing system. The rescheduling methodo...In the environment of customization, disturbances such as rush orders and material shortages often occur in the manufacturing system, so rescheduling is necessary for the manufacturing system. The rescheduling methodology should be able to dispose of the disturbance efficiently so as to keep production going smoothly. This aims researching flow shop rescheduling problem (FSRP) necessitated by rush orders. Disjunctive graph is employed to demonstrate the FSRP. For a flow shop processing n jobs, after the original schedule has been made, and z out of n jobs have been processed in the flow shop, x rush orders come, so the original n jobs together with x rush orders should be rescheduled immediately so that the rush orders would be processed in the shortest time and the original jobs could be processed subject to some optimized criteria. The weighted mean flow time of both original jobs and rush orders is used as objective function. The weight for rush orders is much bigger than that of the original jobs, so the rush orders should be processed early in the new schedule. The ant colony optimization (ACO) algorithm used to solve the rescheduling problem has a weakness in that the search may fall into a local optimum. Mutation operation is employed to enhance the ACO performance. Numerical experiments demonstrated that the proposed algorithm has high computation repeatability and efficiency.展开更多
Due to no effective rescheduling method in hull curved block construction planning, existing scheduling planning can’t be applied in practical production effectively. Two-dimensional layout and dynamic attributes of ...Due to no effective rescheduling method in hull curved block construction planning, existing scheduling planning can’t be applied in practical production effectively. Two-dimensional layout and dynamic attributes of block construction planning are considered to develop a spatial rescheduling method, which is based on the spatial points searching rule and the particle swarm optimization(PSO) algorithm. A dynamic spatial rescheduling method is proposed to solve the manufacturing problem of rush-order blocks. Through spatial rescheduling, the rescheduling start time, the current processing information set and rescheduling blocks set can be obtained automatically. By using and updating the data of these sets, the rescheduling method combines the PSO algorithm with the spatial points searching rule to determine the rescheduling start time and layout of the blocks. Three types of dynamic events, including rush-order block delay, existing block delay and existing block position changes, are used to address problems with different function goals by setting different function weights. Finally, simulations based on three types of rush-order block events are performed to validate this method, including single rush-order block, multi rush-order blocks at the same time and multi rush-order blocks at different times. The simulation results demonstrate that this method can solve the rush-order block problems in hull block construction and reduce the interference to the existing manufacturing schedule. The proposed research provides a new rescheduling method and helps instruct scheduler to make production planning in hull block construction.展开更多
生产过程中紧急订单的到来会影响现有调度方案,甚至造成订单延期交货。以订单延迟交付时间最小为目标,构建带有插单问题的调度模型,使用改进果蝇优化算法(improved fruit fly optimization algorithm,IFOA)寻求带有插单问题的调度最优...生产过程中紧急订单的到来会影响现有调度方案,甚至造成订单延期交货。以订单延迟交付时间最小为目标,构建带有插单问题的调度模型,使用改进果蝇优化算法(improved fruit fly optimization algorithm,IFOA)寻求带有插单问题的调度最优解。考虑三个特征参数建立三维优先级列表来确定订单的优先级从而指导初始中心果蝇的产生,并采用NEH启发式算法和交换策略来寻求周围新个体果蝇,采用基于工序的单层整数编码方式进行编码。使用算例进行测试,插入的紧急订单能够被合理安排,且在求解质量方面IFOA优于顺延插单算法,求解速度方面IFOA优于退单插单算法。展开更多
文摘In the environment of customization, disturbances such as rush orders and material shortages often occur in the manufacturing system, so rescheduling is necessary for the manufacturing system. The rescheduling methodology should be able to dispose of the disturbance efficiently so as to keep production going smoothly. This aims researching flow shop rescheduling problem (FSRP) necessitated by rush orders. Disjunctive graph is employed to demonstrate the FSRP. For a flow shop processing n jobs, after the original schedule has been made, and z out of n jobs have been processed in the flow shop, x rush orders come, so the original n jobs together with x rush orders should be rescheduled immediately so that the rush orders would be processed in the shortest time and the original jobs could be processed subject to some optimized criteria. The weighted mean flow time of both original jobs and rush orders is used as objective function. The weight for rush orders is much bigger than that of the original jobs, so the rush orders should be processed early in the new schedule. The ant colony optimization (ACO) algorithm used to solve the rescheduling problem has a weakness in that the search may fall into a local optimum. Mutation operation is employed to enhance the ACO performance. Numerical experiments demonstrated that the proposed algorithm has high computation repeatability and efficiency.
基金supported by National Natural Science Foundation of China (Grant No. 70872076)Funding of Shanghai Municipal"Science Innovation Action Planning" of China (Grant No. 11dz1121803)
文摘Due to no effective rescheduling method in hull curved block construction planning, existing scheduling planning can’t be applied in practical production effectively. Two-dimensional layout and dynamic attributes of block construction planning are considered to develop a spatial rescheduling method, which is based on the spatial points searching rule and the particle swarm optimization(PSO) algorithm. A dynamic spatial rescheduling method is proposed to solve the manufacturing problem of rush-order blocks. Through spatial rescheduling, the rescheduling start time, the current processing information set and rescheduling blocks set can be obtained automatically. By using and updating the data of these sets, the rescheduling method combines the PSO algorithm with the spatial points searching rule to determine the rescheduling start time and layout of the blocks. Three types of dynamic events, including rush-order block delay, existing block delay and existing block position changes, are used to address problems with different function goals by setting different function weights. Finally, simulations based on three types of rush-order block events are performed to validate this method, including single rush-order block, multi rush-order blocks at the same time and multi rush-order blocks at different times. The simulation results demonstrate that this method can solve the rush-order block problems in hull block construction and reduce the interference to the existing manufacturing schedule. The proposed research provides a new rescheduling method and helps instruct scheduler to make production planning in hull block construction.
文摘生产过程中紧急订单的到来会影响现有调度方案,甚至造成订单延期交货。以订单延迟交付时间最小为目标,构建带有插单问题的调度模型,使用改进果蝇优化算法(improved fruit fly optimization algorithm,IFOA)寻求带有插单问题的调度最优解。考虑三个特征参数建立三维优先级列表来确定订单的优先级从而指导初始中心果蝇的产生,并采用NEH启发式算法和交换策略来寻求周围新个体果蝇,采用基于工序的单层整数编码方式进行编码。使用算例进行测试,插入的紧急订单能够被合理安排,且在求解质量方面IFOA优于顺延插单算法,求解速度方面IFOA优于退单插单算法。
