In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for reco...In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for recoverable item control (METRIC) theory. According to the method of systems analysis, the dynamic palm theorem is introduced to establish the prediction model of the spares demand rate, and its main influence factors are analyzed, based on which, the spares support effectiveness evaluation index system is studied, and the system optimization-oriented spares dynamic configuration method for multi-echelon multi-indenture system is proposed. Through the analysis of the optimization algorithm, the layered marginal algorithm is designed to improve the model calculation efficiency. In a given example, the multi-stage spares configuration project during its life cycle is gotten, the research result conforms to the actual status, and it can provide a new way for the spares dynamic optimization.展开更多
The integration of entire supply and value chain into a closed loop network is gaining more importance in recent times in order to ensure a business to be economically and environmentally sustainable with the changing...The integration of entire supply and value chain into a closed loop network is gaining more importance in recent times in order to ensure a business to be economically and environmentally sustainable with the changing trends in business and social environments, growing environmental consciousness in the society and government legislations to protect the environment as well as the business. In this context, this paper considers a multi-echelon closed loop supply chain network design with forward and reverse logistics components. An attempt has been made to develop a mixed integer non-linear programming model for this problem with different costs so that the sum of the total cost is minimized subject to different constraints pertaining to capacities of the entities of the system, demands of first customers and second customers. A generalized model is presented and then its application is illustrated using an example problem by solving the model using LINGO14. This model forms as a tool to compare future meta-heuristics to check the closeness of their solutions with corresponding optimal solutions.展开更多
The multi echelon inventory system theory (MEIST) ,which is an important branch of inventory theory, is applied mainly in solving the problem of a multi echelon inventory and supply system. In this paper, a brief re...The multi echelon inventory system theory (MEIST) ,which is an important branch of inventory theory, is applied mainly in solving the problem of a multi echelon inventory and supply system. In this paper, a brief review of MEIST is given and its main points are summarized. An application is made to the decision of spares stock levels in maintenance management. The result shows that it can reduce costs of spares by using MEIST in the case of a multi echelon maintenance system.展开更多
As fresh agricultural products are perishable and vulnerable,reducing inventory cost is a strategic target for supply chain enterprises.How to design a reliable multi-echelon inventory control policy is still a great ...As fresh agricultural products are perishable and vulnerable,reducing inventory cost is a strategic target for supply chain enterprises.How to design a reliable multi-echelon inventory control policy is still a great challenge.Therefore,the inventory cost of a three-level fresh agricultural products inventory system was firstly mathematically analyzed.Then,the simulation-based optimization model of the multi-echelon inventory system for fresh agricultural products was proposed by using the Flexsim simulation software and the improved particle swarm optimization algorithm.Finally,the multi-echelon inventory system is simulated based on a large number of survey data.Simulation results demonstrate that the proposed simulation-based optimization model of multi-echelon inventory system for fresh agricultural products can provide decision-making and technical support for the formulation of inventory control policy,and also it shows that the modeling of system simulation is an effective method to solve the problem of complex system.展开更多
针对实际物流中广泛存在的两级车辆路径问题(two-echelon vehicle routing problem,2E-VRP),以最小化总路径长度为优化目标,提出一种基于深度强化学习的模拟退火算法(simulated annealing based on deep reinforcement learning,SADRL)...针对实际物流中广泛存在的两级车辆路径问题(two-echelon vehicle routing problem,2E-VRP),以最小化总路径长度为优化目标,提出一种基于深度强化学习的模拟退火算法(simulated annealing based on deep reinforcement learning,SADRL)进行求解.由于2E-VRP包含两个相互耦合的子阶段,即客户–中转站分配阶段和配送路径规划阶段.不同的客户–中转站分配方案将会影响后续的配送路径优化,故2E-VRP的解空间将十分庞大且复杂.根据以上特点,在SADRL中,首先针对客户–中转站分配问题,设计键–值对的编解码方案,并采用模拟退火算法(simulated annealing,SA)求解客户–中转站分配问题,可将2E-VRP分解为多个VRP子问题;然后,基于分解方案,采用强化学习训练好的注意力模型(attention model-VRP,AM-VRP)获取VRP的优质配送路径,进而可实现对分解方案优劣的快速评价,在降低问题复杂度的同时引导算法高效的探索复杂解空间的优质解区域;最后,针对分解后的多个VRP子问题,设计了结合破坏/重构操作的变邻域下降(variable neighborhood descent with destruction/reconstruction operations,VND_DRO)算法对其配送路径进一步优化,以实现对优质解空间的深入且细致搜索,进而发现处于复杂解空间的深层优质解.通过在不同规模测试集上的实验,证明了本文所提出SADRL求解2E-VRP的有效性.展开更多
基金supported by the National Defense Pre-research Project in 13th Five-Year(41404050502)the National Defense Science and Technology Fund of the Central Military Commission(2101140)
文摘In order to optimize the spares configuration project at different stages during the life cycle, the factor of time is considered to relax the assumption of the spares steady demand in multi-echelon technique for recoverable item control (METRIC) theory. According to the method of systems analysis, the dynamic palm theorem is introduced to establish the prediction model of the spares demand rate, and its main influence factors are analyzed, based on which, the spares support effectiveness evaluation index system is studied, and the system optimization-oriented spares dynamic configuration method for multi-echelon multi-indenture system is proposed. Through the analysis of the optimization algorithm, the layered marginal algorithm is designed to improve the model calculation efficiency. In a given example, the multi-stage spares configuration project during its life cycle is gotten, the research result conforms to the actual status, and it can provide a new way for the spares dynamic optimization.
文摘The integration of entire supply and value chain into a closed loop network is gaining more importance in recent times in order to ensure a business to be economically and environmentally sustainable with the changing trends in business and social environments, growing environmental consciousness in the society and government legislations to protect the environment as well as the business. In this context, this paper considers a multi-echelon closed loop supply chain network design with forward and reverse logistics components. An attempt has been made to develop a mixed integer non-linear programming model for this problem with different costs so that the sum of the total cost is minimized subject to different constraints pertaining to capacities of the entities of the system, demands of first customers and second customers. A generalized model is presented and then its application is illustrated using an example problem by solving the model using LINGO14. This model forms as a tool to compare future meta-heuristics to check the closeness of their solutions with corresponding optimal solutions.
文摘The multi echelon inventory system theory (MEIST) ,which is an important branch of inventory theory, is applied mainly in solving the problem of a multi echelon inventory and supply system. In this paper, a brief review of MEIST is given and its main points are summarized. An application is made to the decision of spares stock levels in maintenance management. The result shows that it can reduce costs of spares by using MEIST in the case of a multi echelon maintenance system.
基金We acknowledge that this work was supported by the science and technology innovation fund of Henan Agricultural University,No.KJCX2016A04Henan province institution of higher learning youth backbone teachers training program,No.2016GGJS-036Henan Provincial Department of Science and Technology Research Project under Grant 192102110205.
文摘As fresh agricultural products are perishable and vulnerable,reducing inventory cost is a strategic target for supply chain enterprises.How to design a reliable multi-echelon inventory control policy is still a great challenge.Therefore,the inventory cost of a three-level fresh agricultural products inventory system was firstly mathematically analyzed.Then,the simulation-based optimization model of the multi-echelon inventory system for fresh agricultural products was proposed by using the Flexsim simulation software and the improved particle swarm optimization algorithm.Finally,the multi-echelon inventory system is simulated based on a large number of survey data.Simulation results demonstrate that the proposed simulation-based optimization model of multi-echelon inventory system for fresh agricultural products can provide decision-making and technical support for the formulation of inventory control policy,and also it shows that the modeling of system simulation is an effective method to solve the problem of complex system.
文摘针对实际物流中广泛存在的两级车辆路径问题(two-echelon vehicle routing problem,2E-VRP),以最小化总路径长度为优化目标,提出一种基于深度强化学习的模拟退火算法(simulated annealing based on deep reinforcement learning,SADRL)进行求解.由于2E-VRP包含两个相互耦合的子阶段,即客户–中转站分配阶段和配送路径规划阶段.不同的客户–中转站分配方案将会影响后续的配送路径优化,故2E-VRP的解空间将十分庞大且复杂.根据以上特点,在SADRL中,首先针对客户–中转站分配问题,设计键–值对的编解码方案,并采用模拟退火算法(simulated annealing,SA)求解客户–中转站分配问题,可将2E-VRP分解为多个VRP子问题;然后,基于分解方案,采用强化学习训练好的注意力模型(attention model-VRP,AM-VRP)获取VRP的优质配送路径,进而可实现对分解方案优劣的快速评价,在降低问题复杂度的同时引导算法高效的探索复杂解空间的优质解区域;最后,针对分解后的多个VRP子问题,设计了结合破坏/重构操作的变邻域下降(variable neighborhood descent with destruction/reconstruction operations,VND_DRO)算法对其配送路径进一步优化,以实现对优质解空间的深入且细致搜索,进而发现处于复杂解空间的深层优质解.通过在不同规模测试集上的实验,证明了本文所提出SADRL求解2E-VRP的有效性.
