This paper employs mathematical modeling and algebraic approach to derive the optimal manufacturing batch size and number of shipment for a vendor-buyer integrated economic production quantity (EPQ) model with scrap. ...This paper employs mathematical modeling and algebraic approach to derive the optimal manufacturing batch size and number of shipment for a vendor-buyer integrated economic production quantity (EPQ) model with scrap. Unlike the conventional method by using differential calculus to determine replenishment lot size and optimal number of shipments for such an integrated system, this paper proposes a straightforward algebraic approach to replace the use of calculus on the total cost function for solving the optimal production- shipment policies. A simpler form for computing long-run average cost for such a vendor- buyer integrated EPQ problem is also provided.展开更多
In this paper, an EPQ-based inventory policy for an item is presented with stock-dependent demand during two trade credit periods. In addition, there is a provision for 1) an immediate part payment to the wholesaler, ...In this paper, an EPQ-based inventory policy for an item is presented with stock-dependent demand during two trade credit periods. In addition, there is a provision for 1) an immediate part payment to the wholesaler, 2) borrowing some money from money lending source for the immediate part payment, 3) here supplier or wholesaler offers a trade credit period to his retailer and retailer also offers a trade credit period to his customer. Against the above conjectures inventory model has been formulated with respect to the retailer’s point of view for minimizing the total inventory cost. The non-linear optimization method-Generalized Reduced Gradient (GRG) method is used to find the optimal solutions. Lastly Numerical examples are set to illustrate this model. Finally we use LINGO software to solve this model.展开更多
During epidemics,controlling the patients’congestion is a way to reduce disease spreading.Raising medical demands converts hospitals into one of the sources of disease outbreaks.The long patient waiting time in queue...During epidemics,controlling the patients’congestion is a way to reduce disease spreading.Raising medical demands converts hospitals into one of the sources of disease outbreaks.The long patient waiting time in queues to receive medical services leads to more casualties.The rise of patients increases their waste,which is another source of disease outbreak.In this study,a mathematical model is developed to control patients’congestion in a medical center and manage their waste,considering environmental issues.Besides a queueing system controlling the patients’congestion in the treatment center,another queue is considered for vehicles.An inventory model is employed to prevent waste accumulation.The developed model is solved and reaches an exact solution in small size,and obtains an acceptable solution in large size using the Grasshopper algorithm.A case study is considered to demonstrate the model’s applicability.Also,Sensitivity analysis and valuable managerial insights are presented.展开更多
随机需求环境下研究柔性制造系统的经济生产批量(Economic Production Quantity,EPQ)模型的最优生产策略问题.在假设需求满足马尔可夫性且为需求状态依赖的条件下,根据顾客的需求程度对市场需求进行状态划分,建立了马氏需求模型,对系统...随机需求环境下研究柔性制造系统的经济生产批量(Economic Production Quantity,EPQ)模型的最优生产策略问题.在假设需求满足马尔可夫性且为需求状态依赖的条件下,根据顾客的需求程度对市场需求进行状态划分,建立了马氏需求模型,对系统未来的需求提出了科学的预测方法.在该模型的基础上,结合柔性制造系统的理论,构建了柔性生产下马氏需求EPQ模型.利用函数的凸性研究了新的EPQ模型的最优解的存在性,进而提出模型的最优(P,Q,T)策略.模型的数值算例表明,利用最优(P,Q,T)策略可以提高制造系统的生产率、缩短产品生产周期及实现小批量的生产模式.展开更多
从现实情况和零售商的利益出发,在零售商允许顾客延期支付的期限不大于零售商从供应商处获得的延期支付期限的假设条件下,基于economic production quantity(EPQ)模型,建立了缺货和顾客部分延期支付并存时零售商的补货模型。以零售商年...从现实情况和零售商的利益出发,在零售商允许顾客延期支付的期限不大于零售商从供应商处获得的延期支付期限的假设条件下,基于economic production quantity(EPQ)模型,建立了缺货和顾客部分延期支付并存时零售商的补货模型。以零售商年总成本最低化为目标,通过计算得到不同情况下零售商的最优补货周期和上个周期末所缺产品的最优补货时间,并对最优解的唯一性进行证明。根据对不同情况下变量限制条件的化简,较快捷地导出相应的条件判定变量,最终给出零售商最优补货策略的确定方法。展开更多
文摘This paper employs mathematical modeling and algebraic approach to derive the optimal manufacturing batch size and number of shipment for a vendor-buyer integrated economic production quantity (EPQ) model with scrap. Unlike the conventional method by using differential calculus to determine replenishment lot size and optimal number of shipments for such an integrated system, this paper proposes a straightforward algebraic approach to replace the use of calculus on the total cost function for solving the optimal production- shipment policies. A simpler form for computing long-run average cost for such a vendor- buyer integrated EPQ problem is also provided.
文摘In this paper, an EPQ-based inventory policy for an item is presented with stock-dependent demand during two trade credit periods. In addition, there is a provision for 1) an immediate part payment to the wholesaler, 2) borrowing some money from money lending source for the immediate part payment, 3) here supplier or wholesaler offers a trade credit period to his retailer and retailer also offers a trade credit period to his customer. Against the above conjectures inventory model has been formulated with respect to the retailer’s point of view for minimizing the total inventory cost. The non-linear optimization method-Generalized Reduced Gradient (GRG) method is used to find the optimal solutions. Lastly Numerical examples are set to illustrate this model. Finally we use LINGO software to solve this model.
文摘During epidemics,controlling the patients’congestion is a way to reduce disease spreading.Raising medical demands converts hospitals into one of the sources of disease outbreaks.The long patient waiting time in queues to receive medical services leads to more casualties.The rise of patients increases their waste,which is another source of disease outbreak.In this study,a mathematical model is developed to control patients’congestion in a medical center and manage their waste,considering environmental issues.Besides a queueing system controlling the patients’congestion in the treatment center,another queue is considered for vehicles.An inventory model is employed to prevent waste accumulation.The developed model is solved and reaches an exact solution in small size,and obtains an acceptable solution in large size using the Grasshopper algorithm.A case study is considered to demonstrate the model’s applicability.Also,Sensitivity analysis and valuable managerial insights are presented.
文摘随机需求环境下研究柔性制造系统的经济生产批量(Economic Production Quantity,EPQ)模型的最优生产策略问题.在假设需求满足马尔可夫性且为需求状态依赖的条件下,根据顾客的需求程度对市场需求进行状态划分,建立了马氏需求模型,对系统未来的需求提出了科学的预测方法.在该模型的基础上,结合柔性制造系统的理论,构建了柔性生产下马氏需求EPQ模型.利用函数的凸性研究了新的EPQ模型的最优解的存在性,进而提出模型的最优(P,Q,T)策略.模型的数值算例表明,利用最优(P,Q,T)策略可以提高制造系统的生产率、缩短产品生产周期及实现小批量的生产模式.
文摘从现实情况和零售商的利益出发,在零售商允许顾客延期支付的期限不大于零售商从供应商处获得的延期支付期限的假设条件下,基于economic production quantity(EPQ)模型,建立了缺货和顾客部分延期支付并存时零售商的补货模型。以零售商年总成本最低化为目标,通过计算得到不同情况下零售商的最优补货周期和上个周期末所缺产品的最优补货时间,并对最优解的唯一性进行证明。根据对不同情况下变量限制条件的化简,较快捷地导出相应的条件判定变量,最终给出零售商最优补货策略的确定方法。
