Most of the spare ordering policies treated up to now have assumed that preventive and corrective replacement costs are equal, which implies in essential that there is no significant need for preventive replacement. T...Most of the spare ordering policies treated up to now have assumed that preventive and corrective replacement costs are equal, which implies in essential that there is no significant need for preventive replacement. This paper presents an ordering policy for preventive age replacement with minimal repair. Introducing the replacement, repair, inventory holding and shortage costs, the expected cost rate is derived. A procedure to determine jointly the ordering time for a spare and the preventive replacement time for the operating unit so as to minimize the expected cost rate is proposed. To explain the ordering policy and the optimization procedure, a numerical example is also included.展开更多
This study considers an age replacement policy(ARP) for a repairable product with an increasing failure rate with and without a product warranty. As for the warranty policy to consider in association with such an age ...This study considers an age replacement policy(ARP) for a repairable product with an increasing failure rate with and without a product warranty. As for the warranty policy to consider in association with such an age replacement policy, we adapt a renewable minimal repair-replacement warrant(MRRW) policy with 2D factors of failure time of the product and its corresponding repair time. The expected cost rate during the life cycle of the product is utilized as a criterion to find the optimal policies for both with and without the product warranty. We determine the optimal replacement age that minimizes the objective function which evaluates the expected cost rate during the product cycle and investigate the impact of several factors on the optimal replacement age. The main objective of this study lies on the generalization of the classical age replacement policy to the situation where a renewable warranty depending on 2D factors is in effect. We present some interesting observations regarding the effect of relevant factors based on numerical analysis.展开更多
Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution betw...Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution between cemented long展开更多
In this paper, we consider the replacement of a single unit with catastrophic failure mode. Besides replaced at a preset time, the unit is also replaced at failure time or if it encounters a production wait and its ag...In this paper, we consider the replacement of a single unit with catastrophic failure mode. Besides replaced at a preset time, the unit is also replaced at failure time or if it encounters a production wait and its age has reached a threshold. The joint preventive maintenance interval and threshold optimization problem are formulated with the objective of minimizing the expected cost per unit time in long run. A numerical example is presented to illustrate the applicability of the model.展开更多
文摘Most of the spare ordering policies treated up to now have assumed that preventive and corrective replacement costs are equal, which implies in essential that there is no significant need for preventive replacement. This paper presents an ordering policy for preventive age replacement with minimal repair. Introducing the replacement, repair, inventory holding and shortage costs, the expected cost rate is derived. A procedure to determine jointly the ordering time for a spare and the preventive replacement time for the operating unit so as to minimize the expected cost rate is proposed. To explain the ordering policy and the optimization procedure, a numerical example is also included.
基金the National Research Foundation of Korea Grant(NRF-2014S1A5A8012594)the 2014Hongik University Research Fund,the Basic Science Research Program Through the National Research Foundation of Korea(Nos.2013-2058436 and 2011-0022397)the Basic Science Research Program Through the National Research Foundation of Korea
文摘This study considers an age replacement policy(ARP) for a repairable product with an increasing failure rate with and without a product warranty. As for the warranty policy to consider in association with such an age replacement policy, we adapt a renewable minimal repair-replacement warrant(MRRW) policy with 2D factors of failure time of the product and its corresponding repair time. The expected cost rate during the life cycle of the product is utilized as a criterion to find the optimal policies for both with and without the product warranty. We determine the optimal replacement age that minimizes the objective function which evaluates the expected cost rate during the product cycle and investigate the impact of several factors on the optimal replacement age. The main objective of this study lies on the generalization of the classical age replacement policy to the situation where a renewable warranty depending on 2D factors is in effect. We present some interesting observations regarding the effect of relevant factors based on numerical analysis.
文摘Objective To investigate the stress distribution of the femur after cemented prosthetic replacement in aged patients with comminuted intertrochanteric fracture and to analyze the difference of stress distribution between cemented long
基金the National Natural Science Foundation of China(Nos.11426084,11001005,71231001,71301009 and 71420107023)the China Postdoctoral Science Foundation Funded Project(No.2013M530531)+2 种基金the Natural Science Foundation of Hebei Province(No.A2014208133)the Foundation of Hebei Education Department(No.QN2014132)the Ministry of Education Doctor of Philosophy Supervisor Fund(No.20120006110025)
文摘In this paper, we consider the replacement of a single unit with catastrophic failure mode. Besides replaced at a preset time, the unit is also replaced at failure time or if it encounters a production wait and its age has reached a threshold. The joint preventive maintenance interval and threshold optimization problem are formulated with the objective of minimizing the expected cost per unit time in long run. A numerical example is presented to illustrate the applicability of the model.
