• Journal of Korean Society of Industrial and Systems Engineering
• /
• 제21권47호
• /
• pp.87-99
• /
• 1998

This study is concerned with a problem of determining the optimal requirements level of the spare parts, especially Concurrent Spare Parts(CSP). CSP is supplied with the procurement of new equipment system, and is used to sustain the equipment without resupply during the initial coverage period. We consider this situation as a multiechelon inventory model with several bases and one depot. And we assume a equipment system which consists of many types of parts would grounded if one of the parts fail. Also this multiechelon CSP problem is considering a time-varing (dynamic) environment. We develop a computational procedure to find the optimal number of spare parts minimizing the total expected cost, while achieving the required system availability. Finally we present a simple example of suggested method.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
• /
• 한국산업경영시스템학회 2002년도 춘계학술대회
• /
• pp.189-194
• /
• 2002

As a environment of SCM is issued recently, many enterprises are concerned about inventory control for an efficiency of operation and reliablity. The goal of them is to match up to improving of facilities and redoing of inventory cost. To put an efficiency in the operation rate of facilites, A moderate provision of spare parts for that would come into a matter. This study designs two-echelon spare parts distribution system and sees over the relationship between operating rate and inventories of spare parts. and then it determines fitting inventories and investment cost considering an operating rate.

• Korean Management Science Review
• /
• 제27권2호
• /
• pp.31-44
• /
• 2010

It is very important to forecast demand and determine the optimal procurement quantities of spare parts. The Army has been forecasting demand not with actual usage of spare parts but with request quantities. However, the Army could not purchase all of forecasted demand quantities due to budget limit. Thus, the procurement quantities depend on the item managers' intuition and their meetings. The system currently used contains many problems. This study suggests a new determination procedure; 1) forecasting demand method based on actual usage, 2) determining procurement method through LP model with budge and other constraints. The newly determined quantities of spare parts is verified in the simulation model, that represents the real operational and maintenance situation to measure the operational availability. The result shows that the new forecasting method with actual usage improves the operational availability. Also, the procurement determination with LP improves the operational availability as well.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• 제30권3호
• /
• pp.117-126
• /
• 2007

It has been a major issue to repair the broken system quickly for improvement of productivity and utilization. Generally, high utilization of system requires the high amount of spare parts in inventory and inventory cost. Therefore, it is necessary to determine the proper amount of inventory with regard to utilization of system. This study designs a methodology for determining the proper amount of inventory level in a two-echelon spare parts distribution system. The requirements are to satisfy proper customer demands at a distribution center and to maintain over the utilization of the whole system at customers. This methodology minimizes total inventory investment at a distribution center and customers.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• 제40권4호
• /
• pp.253-259
• /
• 2017

Recent development in science and technology has modernized the weapon system of ROKN (Republic Of Korea Navy). Although the cost of purchasing, operating and maintaining the cutting-edge weapon systems has been increased significantly, the national defense expenditure is under a tight budget constraint. In order to maintain the availability of ships with low cost, we need accurate demand forecasts for spare parts. We attempted to find consumption pattern using data mining techniques. First we gathered a large amount of component consumption data through the DELIIS (Defense Logistics Intergrated Information System). Through data collection, we obtained 42 variables such as annual consumption quantity, ASL selection quantity, order-relase ratio. The objective variable is the quantity of spare parts purchased in f-year and MSE (Mean squared error) is used as the predictive power measure. To construct an optimal demand forecasting model, regression tree model, randomforest model, neural network model, and linear regression model were used as data mining techniques. The open software R was used for model construction. The results show that randomforest model is the best value of MSE. The important variables utilized in all models are consumption quantity, ASL selection quantity and order-release rate. The data related to the demand forecast of spare parts in the DELIIS was collected and the demand for the spare parts was estimated by using the data mining technique. Our approach shows improved performance in demand forecasting with higher accuracy then previous work. Also data mining can be used to identify variables that are related to demand forecasting.

• Korean Management Science Review
• /
• 제26권1호
• /
• pp.209-223
• /
• 2009

In this paper, an analysis problem of repair levels and spare part allocation for MIME(Multi indenture multi echelon) systems is studied using simulation and meta-heuristics. We suggest a method to determine simultaneously repair levels and spare parts allocation to minimize the life cycle cost of MIME system under availability constraint. A simulated annealing method is used to analyze the repair levels and genetic algorithm is used to obtain the optimal allocation of spare parts. We also develop a simulation system to calculate the life cycle cost and system availability. Some numerical examples are also studied.

• Journal of Korean Society for Quality Management
• /
• 제36권2호
• /
• pp.9-19
• /
• 2008

Spare part problem of MIME (Multi Indenture Multi Echelon) system under availability constraint has been studied for several decades. In most of existing studies, it was very difficult to obtain the optimal numbers of spare parts and some approximate methods were proposed under many restrictions. In this paper, we consider a simulation to estimate the total cost rate and system availability and a genetic algorithm to obtain the optimal numbers of spare parts. Some numerical examples are also studied.

• Journal of Aerospace System Engineering
• /
• 제13권1호
• /
• pp.54-61
• /
• 2019

The 3D printing technology took the second place within the top ten rising technologies at the World Economic Forum in 2012. It arose as a core technology that would enable transformation in the manufacturing industry and develop new markets through the change of existing industry paradigms. Leading countries, like the United States of America, are actively expanding the use of 3D printing technologies within their defense areas. In order to utilize the technology within her defense areas, the Republic of Korea is planning to acquire defense spare parts manufacturing technologies and nurture professional defense personnel specializing in the 3D printing technology. Hence, this study offers various methods to efficiently apply reliable 3D printing spare parts to operation fields in the future by utilizing spare parts localization development management methods within existing weapon systems' development, manufacturing and sustainment phases.

• Journal of Applied Reliability
• /
• 제2권2호
• /
• pp.85-97
• /
• 2002

In this paper, partially repairable concurrent spare parts requirement determination problem of newly procured equipment systems is considered. “partially repairable” means that a portion of damaged parts can be recover their function and reused after repairs. A mathematical model is derived for making an CSP requirement determination subject to the constraint of satisfying any given operational availability limitation. We assume that the failure of a part follows a Poisson process and the repair time has an exponential distribution. Using the generalized Lagrange multipliers method, the solution procedure is derived.

• Journal of the Korean Society for Precision Engineering
• /
• 제23권3호
• /
• pp.132-138
• /
• 2006

With a great requirement of innovation caused by severe competition current companies are encouraged to improve bottleneck areas in production procedure. Specially a chassis line in which assembly processes are mainly carried out manually has the large potential to be automated. The putting of spare tire in trunk in chassis line is still dominated by free dropping method. Through that, parts in trunk such as luggage room lamp, jack and so on were damaged and the complaint of assembler in the next process was occurred due to physical strength. To eliminate these, tile robot system was in this paper developed to place spare tire on the mounting hole in trunk. The movement of robot was synchronized with the velocity of chassis hanger. With this automated system the productivity of the chassis line was increased from the benefits such as simplification of the system using only robot without the mechanically synchronized transport, inserting spare tire into the right position with robot, reduction of damaged parts and production of various type of car.