• Journal of Chest Surgery
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• 제20권4호
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• pp.780-785
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• 1987

Pulmonary atresia with VSD is uncommon congenital anomaly with high mortality in neonatal period. Recently we experienced surgical correction of 2 cases of pulmonary atresia with VSD. The first case was 7-year old female patient and diagnosed as pulmonary atresia with VSD combined PDA. So, total correction was undertaken which consisted of PDA ligation, patch repair of VSD, transannular enlargement of RVOT with woven Dacron vascular graft, and closure of PFO. Postoperative systemic Rt. ventricular and radial artery pressure ratio was 0.44 and her postoperative course was uneventful. The second case was 6-year old male patient diagnosed as pulmonary atresia with VSD and large systemic-pulmonary collateral arteries. There were two large systemic-pulmonary collaterals, one was simply controlled by ligation, but the other was considered to supply Rt. upper lung. So end to side anastomosis was performed to the RVOT patch. Postoperative systolic Rt. ventricular and radial artery pressure ratio was 0.54. During the follow up period he showed clinical picture of Rt. heart failure, which is relatively well controlled with anticongestive therapy.

• 한국경영과학회지
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• 제20권1호
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• pp.55-62
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• 1995

This paper compares the two policies which are unsed in Korean electronic appliance industry. Policy I is a general warranty policy under which all of failures during warrenty period (12 months) are repaired without charge. Policy II was proposed recently by a company. Under Policy II, when the product fails until a certain times(6 months), the failed product will be replaced by the new product and all other failures from the certain time to the warrenty period (24 months) will be repaired free. We obtain the expected total warranty costs per product and necessary conditions under which the Policy II has a meaning in economic point of view without or with discount rate. Some numericla examples are considered.

• 교육시설 논문지
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• 제19권5호
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• pp.21-28
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• 2012

Current maintenance costs of the educational facilities have been determined by the years of services according to their foundation year. However, these maintenance costs have not considered maintenance and repairing. Therefore, this study suggests a new method to recalculate the years of services of schools by using the data of maintenance and repairing which is stored in the CAD drawing of the educational facilities. Also, since the data of maintenance and repairing has to be kept only for 5 years, the data is limited for the BTL project which has a maintenance period of 20 years. Thus, this study developed a new model to expand 5 years' data to the period of 20 years. This proposed model is expected to contribute in the maintenance and repairing of the BTL project.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2001년도 학술논문발표회
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• pp.136-141
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• 2001

If we build new building after demolition of commercial building that is located in the downtown, it will be caused a social and environmental problem as wasting of resources and generating of waste. In this study, I investigated about remodel ins, this conclusion is given below. 1. Reconstruction cost is 2.1 times, and construction period is 1.4 times as much remodeling. So remodeling has an advantage. 2. For repairing and reinforcing timeworn building, we reinforced it as using carbon fiber sheet (girder, slab) and injecting method steel plate bonding Also, we tried to maintain efficiency of new building as using epoxy to protect concrete crack. 3. In the side of waste products and cost, remodeling has much more advantage than reconstruct. But demolition used construction period much. Because it had to be reused as repairing and reinforcing. And there was no difference between remodeling cost and reconstruct cost. If we develop research with enterprise.university.laboratory to exploit material and equipment and to train specialized engineer who will has a capacity to know construct repair and reinforce, it can be attribute to prevail remodeling in new construct market.

• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.889-901
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• 2003

In this paper, we consider the optimal replacement policies following the expiration of the combination warranty. The combination warranty can be divided into the renewing combination warranty and the non-renewing combination warranty. The criterion used to determine the optimal replacement period is the overall value function based on the expected cost and the expected downtime. Thus, we obtain the expected cost rate per unit time and the expected downtime per unit time for our model. And then the overall value function suggested by Jiagn and Ji(2002) is applied to obtain the optimal replacement period. The numerical examples are presented for illustrative purpose.

• Archives of Reconstructive Microsurgery
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• 제4권1호
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• pp.52-57
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• 1995

The authors have reviewed 19 patients of brachial plexus injury who treated by operative methods at Department of Orthopedic Surgery, Korea University Hospital during the period from January 1989 to February 1994. All of these patients were followed up more than one year and following results were obtained. 1. The whole arm type injury was most common(7 of 19 patient) and supraclavicular lesion(15 of 19 patient) was more dominant than infraclavicular lesion(4 of 19 patients). 2. The neurorrhaphy, nurolysis, nerve grafting, and neurotization were performed for the primary neural surgery and secondary reconstructive procedure consist of musculotendinous transfer and free muscle transfer with neurotization. 3. The followed up period was from one year to four years and six months, average being two years and five months. 4. We have obtained satisfactory results in 12 patients among 19 patients.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2001년도 학술대회지
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• pp.113-118
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• 2001

사용중인 교량의 안전성, 사용성, 내구성을 확보하기 위한 시발점은 교량에 대한 점검과 진단이다. 본 논문에서는 최근 개정된 시설물 안전진단에 관한 특별법에 제시된 점검주기와 독일의 점검주기를 비교하고, 외국의 손상 보고서에 나타난 손상발견시기를 분석하였으며, 분석 결과를 기초로 국내 진단 주기의 재조정을 제안하였다. 이를 위해 비교 대상인 양국의 교량 현황을 살펴보고, 유지관리 체계와 비용을 객관적 비교근거로 제시하였다.

• Journal of Computational Design and Engineering
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• 제2권2호
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• pp.119-127
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• 2015

In the case of a high-valuable asset, the Operation and Maintenance (O&M) phase requires heavy charges and more efforts than the installation (construction) phase, because it has long usage life and any accident of an asset during this period causes catastrophic damage to an industry. Recently, with the advent of emerging Information Communication Technologies (ICTs), we can get the visibility of asset status information during its usage period. It gives us new challenging issues for improving the efficiency of asset operations. One issue is to implement the Condition-Based Maintenance (CBM) approach that makes a diagnosis of the asset status based on wire or wireless monitored data, predicts the assets abnormality, and executes suitable maintenance actions such as repair and replacement before serious problems happen. In this study, we have addressed several aspects of CBM approach: definition, related international standards, procedure, and techniques with the introduction of some relevant case studies that we have carried out.

• 산업경영시스템학회지
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• 제20권43호
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• pp.357-364
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• 1997

After the buyer purchases the product, the seller's role does not end. If the product fails to function properly before the end of the warranty period, the seller is responsible for its repair or replacement under the seller's warranty policy. There are two common types of warranty policies: the free replacement warranty and the rebate warranty. Under the free replacement warranty policy, replacement or repairs during the warranty period are provided by the seller free of charge to the buyer. Under the rebate warranty policy, a failed item is replaced by a new one or is repaired at a cost to the age of the failed item. The rebate warranty is most often used for items such as a battery or an automobile tire which wear out and must be replaced at failure. This paper proposes a easy way of estimating the warranty cost under the free replacement warranty policy assuming an exponential product failure function on repairable products.

• 대한안전경영과학회지
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• 제25권3호
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• pp.1-7
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• 2023

As the capacity of renewable power generation facilities rapidly increases, the variability of electric power system and gas turbine power generation is also increasing. Therefore, problems may occur that require urgent repair while the gas turbine rotor is stopped. When the gas turbine rotor turning is stopped and then restarted, if the turning period is not appropriate, severe vibration may occur due to rotor bending. As a result of the experiment, it was confirmed that normal operation is possible when the gap data measured at the start of rotor turning after maintenance work is similar to the existing value. And the vibration value at the start of rotor turning was lower as the rotor temperature was lower or the stop period was shorter.