• Journal of Applied Reliability
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• v.7 no.3
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• pp.119-126
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• 2007

This paper deals with (s, S) spare part inventory model. Maintaining appropriate spare parts is one of the most important military affairs related to the readiness of military forces. In the problem under consideration, a military unit possesses n equipments and all the n equipments should be in operational readiness for the military purpose. The lifetime distribution of a part has been assumed to be exponential. This paper suggests the reorder point and order quantity under the assumption that the lifetime distribution of a part is weibull.

• Archives of Plastic Surgery
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• v.46 no.4
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• pp.371-374
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• 2019

Umbilical preservation can be challenging, particularly in complex cases involving simultaneous ventral hernia repair and abdominoplasty. Although the umbilicus serves no functional purpose, removal of the umbilicus can draw unwanted attention to the abdominal area and can cause emotional distress to patients. There are several well documented options for umbilical reconstruction. We present a new umbilical reconstruction technique relevant for such cases. This neoumbilicoplasty allows for preservation of the original umbilicus with relocation and reconstruction using local flaps. The technique is relatively simple and the time needed is minimal. The result is a natural, well positioned umbilicus using the principles of spare part surgery.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.1
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• pp.120-125
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• 2015

Passengers and Airlines wish neither delay nor cancellation due to aircraft defects. However, about 1 delay or cancellation case occurs out of 100 departures worldwide whereas 1 quarter case does in Korean domestic industry. Independent LCC carriers in Korea have almost double case. Most cases are recovered by replacing aircraft components. Airlines have prepared the spare components based on the reliability data by manufacturers to rectify defects or perform preventive maintenances. The total value for initial spares including engine is 40% of the aircraft price when they operate less than 5 aircraft. The more airlines operate the aircraft, the less the ratio of the investment for spares reflecting the economy of scale. This study intends to suggest how to improve the efficiencies as well as the safety of LCC throughout parts pooling including engines.

• Journal of the Korean Society for Railway
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• v.9 no.5 s.36
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• pp.555-560
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• 2006

This study finds out and suggests success factors for the application of RIMS project through the case study of Seoul Metro and literature survey. The successful application of RIMS needs expert knowledge and concept of BOM, standardization of maintenance planning, check lists of heavy maintenance inspection, organization structure of rolling stock maintenance offices, material management system of warehousing and the process of parts repairing between offices, connection of material ordering system, problem solving of circular spare parts administration among inspection, maintenance, and material organizational units, systemic serial number management of parts with RFID, daily closing diary connected with work process chart, and sufficient period of RIMS's test run. RIMS contributes to real time management of rolling stock maintenance, transparency of management, reliability of train operation, customer satisfaction, and management innovation.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.23 no.59
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• pp.53-67
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• 2000

In this paper we consider the CSP requirements determination problem of new equipment(machine) system. For the newly procured equipment systems, mathematical analyses are made for the system which is constructed with the consumable parts and the repairable parts to derive the associated CSP requirement determination model in mathematical expression. Based on these analyses, a mathematical model Is derived for making an optimal 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. Firstly, the operational availability concept in CSP is defined and the relation between the general system availability and the operational availability is established. Secondly, the problem is formulated as the cost minimization problem that should satisfy the operational availability limitation, and then, using the generalized Lagrange multipliers method, the optimal solution procedure Is derived.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.315-322
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• 2019

Recently, the Marine Corps of South Korea started to introduce and possess its own weapon systems. On the other hand, the level of maintenance is lower than that of other military forces, and depending on the other military forces, maintenance occurs intermittently when transporting weapons systems. In this case, unmanned vehicles can be used to reduce the cost, manpower, time, and risk of carrying weapons systems. In addition, the transport of weapon systems between islands or between an island and inland of the Marine Corps using unmanned vehicles is easier in terms of the maintenance level and surrounding environment than other military forces. This paper compares the improvement of operational availability and cost of spare parts in terms of logistics support when using unmanned vehicles in the West Sea area, and quantitatively show the efficiency and usability of the weapon system. To compare operational availability and costs for spare parts, a simulation was performed based on the OO weapons system between islands or between an island and inland, and the results were compared and analyzed.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.37 no.4
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• pp.24-34
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• 2014

In order to manage essential parts that are required for the repairable parts services performed at the military maintenance depots, the United States Air Force developed the Repairability Forecasting Model (RFM). In the RFM, if the requirements of the parts are assumed to follow the normal probability distribution after applying means from the past data to the replacement rate and lead times, the chance of the AWP (Awaiting Parts) occurring is 50%. In this study, to counter the uncertainties of requirements and lead times from the RFM, the safety level concept is considered. To obtain the safety level for requirements, the binomial probability distribution is applied, while the safety level for lead time is obtained by applying the normal probability distribution. After adding this concept, the improved RFM is renamed as the ARFM (Advanced RFM), and by conducting the numerical stimulation, the effectiveness of the ARFM, minimizing the occurrence of the AWP, is shown by increasing the efficiency of the maintenance process and the operating rate of the weapon system.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.193-201
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• 2019

The purpose of this study is to investigate the internal and extrnal factors of procurement of non-bid parts in the overseas militaries products for commercial purchase after deploy at Militaries. How we will continures to support of Primary of delivery to end users for all systems for maintenance support equipment products of Korean militaries. the purpose of this study is to propose a development direction for solving hard to find parts and non-bid products problem due to non-response of overseas repair parts suppliers.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.1116-1117
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• 2005

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.10a
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• pp.607-610
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• 2004

The purpose of this study is finding a solution to optimal quantities of concurrent spare parts(CSP) which are acquired for using considerably long time. To solve the problem, this paper proposes a new CSP model which can be used in permitting backorder flexibly. Through the simple experiment, we validate the mathematical model which is suggested in this paper. Also, we determine the purchasing quantities of each item minimizing total system costs under an available budget constraints.