• Journal of the Korean Data and Information Science Society
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• 제14권2호
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• pp.393-403
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• 2003

In this paper, various replacement policies for the general failure model are considered. There are two types of failure in the general failure model. One is Type I failure (minor failure) which can be removed by a minimal repair and the other is Type II failure (catastrophic failure) which can be removed only by a complete repair. In this model, when the unit fails at its age t, Type I failure occurs with probability 1-p(t) and Type II failure occurs with probability p(t), $0{\leq}p(t){\leq}1$. Under the model, optimal replacement policies for the long-run average cost rate and the limiting efficiency are considered. Also taking the cost and the efficiency into consideration at the same time, the properties of the optimal policies under the Cost-Priority-Criterion and the Efficiency-Priority-Criterion are obtained.

• 대한관절경학회지
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• 제17권1호
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• pp.71-75
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• 2013

내측 반월상 연골 뿌리 파열은 외상이나 퇴행성으로 생길 수 있으며, 이로 인해 반월상 연골의 돌출, 관절 연골의 손상, 골극의 생성, 내측 관절 간격의 협소를 유발 할 수 있다. 이는 중년이상의 나이에서 주로 발생하며, 외상을 동반하거나 외상없이 생길 수 있다. 본 저자는 13세 청소년에서 야구 경기 도중 발생한 내측 반월상 연골 후각부 뿌리 파열 1예를 경험하였고, 관절경하에 suture anchor를 이용한 직접적 봉합술을 시행하였기에 이를 보고하고자 한다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 추계 학술발표회 제17권2호
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• pp.551-554
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• 2005

The durability of concrete is decreased by various deterioration factors such as a crack, spalling, corrosion. Many repair and rehabilitation methods have been introduced to extend service life of RC structure. An application of coating material is one of repair and rehabilitation methods. However, there is a problem due to reduction of bonding strength and damage of coating material in the case of existed coating material. Thus, this paper is aim to investigate the chloride resistance according to application method of coating material which improve the existed problem. According to the results, it is showed that application of coating material reduces diffusion of chloride into concrete. In special, application of MMA polymer showed the best resistance for chloride attack. However, variation of application method and number of times has a minor effect on chloride diffusion.

• Journal of the Korean Data and Information Science Society
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• 제14권4호
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• pp.997-1005
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• 2003

In this paper, the problem of determining optimal burn-in time is considered under a general failure model. There are two types of failure in the general failure model. One is Type I failure (minor failure) which can be removed by a minimal repair and the other is Type II failure (catastrophic failure) which can be removed only by a complete repair. In this model, when the unit fails at its age t, Type I failure occurs with probability 1 - p(t) and Type II failure occurs with probability p(t), $0{\leq}p(t)\leq1$. Under the model, the properties of optimal burn-in time maximizing mean time to the catastrophic failure during field operation are obtained. The obtained results are also applied to some illustrative examples.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.539-544
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• 2004

In this paper, we present reliability modeling and analysis method of the Automated Guideway Transit(AGT) vehicle system using analytical models, based on Markov Chains. The Markov model can express state transition of the AGT vehicle sys. that is considered to be in one of four states, such as basic operating (0), minor delay(1), major delay(2) and non-operating(3) state. The proposed Markov model is illustrated with a numerical example and cases to find a steady state availability, MTBF(mean time between failures), and MTTR(mean time to repair) under specified failure and repair rate arc demonstrated.

• 한국자동차공학회논문집
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• 제24권4호
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• pp.432-438
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• 2016

Whiplash injuries in low-speed rear-end collisions are the most common injuries and has been a social issue in insurance industry, such as excessive medical claim costs along with exaggerated injuries of victims and treatments from hospitals. According to the Korea Insurance Development Institute reports, the number of claims by rear-end collision was approximately 703,000, which accounts for 53.6 % of the total car-to-car collisions in 2014. Part of the neck injury claims in the Korea car insurance was approximately 28.3 %. Furthermore, approximately 98.4% of the injured persons in rear-end collisions sustained minor injuries under AIS2. In order to improve this situation as well as find out the severity of neck injuries from rear-end collision, the Korea Automobile Insurance Repair Research and Training Center conducted car-to-car rear-end crash tests that striking vehicles(SUV) collided into different sizes of struck-vehicles(small, middle, and large sedan) at the impact speeds of 8 km/h ~ 16 km/h. In order to analyze the whiplash injury, the BioRID-II was seated in each struck-vehicles, and the neck injury criteria(NIC), head contact time, maximum vehicle accelerations, and mean vehicle accelerations were calculated from values from the accelerations of the dummy and the struck-vehicles.

• 한국정밀공학회지
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• 제20권8호
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• pp.54-61
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• 2003

The first stage rotating blade of industrial gas turbine is one of the components that is normally run in exposed state at the highest temperature of the combustion gas stream. For this reason superior materials and advanced cooling technology are required to allow higher heat resisting characteristics of the component. The 1st stage blade of a selected commercial gas turbine blade made of directionally solidified Ni-based superalloy has a row of cooling holes on its trailing edge. In most cases, minor cracks have been found at some of the root cooling holes after one cycle operation (24,000 hrs) or even shorter operation time because of the high temperature gradient and the frequently alternating thermal stress. In the repair process, unfortunately, it is usually very difficult to get rid of the damage due to the fact that cracks are initiated at the root cooling hole and propagated deep into the hole. In this study, the feasibility of removing the sidewall cracks in the hole by utilizing EDM drilling has been investigated. Also the criteria of surface integrity for EDM drilling were established to achieve high quality repair as well as machining accuracy.

• Journal of Chest Surgery
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• 제19권4호
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• pp.627-632
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• 1986

This report describes our 17-years experience with intracardiac repair in 123 patients older than 15 years with tetralogy of Fallot. Major clinical manifestation was cyanosis and clubbing [102 Pts], but other minor associated manifestation were infective endocarditis, pulmonary tuberculosis, brain abscess, congestive heart failure, nephrotic syndrome, and tuberculous spondylitis. Prior palliative shunts had been performed in 10 patients. Preoperative hemoglobin ranged from 9.7 gm/dl to 25 gm/dl [mean 19 gm/dl]. The type of ventricular septal defect were typical perimembranous type, and total canal defect [13%]. The right ventricular outflow tract obstruction was due to combined [58.5%], infundibular [35%], and valvular stenosis [6.5%]. Transannular patch was used in 17% of patients. Hospital mortality was 9.8% in overall, but decreased to 1.7% since 1982. There was two late death [12 year actuarial survival [97%] due to fulminant hepatitis, residual abnormalities [PS, VSD]. Ninety two percent of survivors at follow-up are asymptomatic and leading an active normal life. Residual ventricular septal defect was detected with radionuclide single pass study in 15.3% of patients but almost cases were Qp/Qs less than 1.5, and only two patients had been candidates for reoperation.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권1호
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• pp.71-78
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• 2007

The nasolabial flap has been used for reconstruction of moderate size intraoral defects. The nasolabial fold area provides an ample supply of tissue with a good color and texture match. The nasolabial flap classified advancement flap, inferiorly-based flap, superiorly-based flap. The flap is based inferiorly, so that it can easily be rotated to the intraoral defects. The nasolabial flap is chosen for the repair of various intraoral defects because of its simple elevation, proximity to the defect and its rich subcutaneous blood supply of a island flap. The subjects were 6 patients with nasolabial flap, who had reconstruction of moderate size intraoral defects. We have found the inferiorly-based nasolabial flap with a subcutaneous pedicle useful in the primary repair of surgical defects of the buccal mucosa, edentulous mandibular ridge, maxillary alveolus area and soft palate in these patients. There was no complication except one case. Intraoral hair growth was a minor problem of this patient. We thought that the inferiorly-based nasolabial flap is a useful technique for reconstruction of various intraoral defects.

• 한국전통조경학회지
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• 제41권1호
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• pp.21-34
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• 2023

본 연구는 13개 마을 옛 담장의 국가등록문화재 지정 당시 사용된 재료와 축조법을 파악하고, 현장조사를 중심으로 정비에 따른 옛 담장의 구조별 변화 양상을 고찰하였다. 연구의 결과는 다음과 같다. 첫째, 옛 담장은 토석담 10개소와 돌담 5개소로 구성되었으며, 지정 당시 자연석 메쌓기로 막쌓은 돌담은 비슷한 형태를 유지하는 비율이 높았지만, 토석담은 사용한 돌과 줄눈 및 맞댄 면 축조법에 따라서 담장별로 다양하게 변형되었다. 둘째, 옛 담장의 정비로 인해서 변화된 구간을 추출하고 재료의 대체와 첨가, 축조법의 변형 양상을 파악하였다. 지붕부는 내구성과 가격의 효율이 높은 시멘트 기와나 석면 슬레이트로 대체되고, 우수 유입을 막고자 한식 기와에 와구토가 첨가되었다. 벽체부의 자연석은 시공 편의에 따른 발파석, 마름돌, 가공 석재로 대체되고, 보수에 시멘트 블록, 시멘트 벽돌이 사용되었으며, 시멘트 모르타르가 도포되었다. 토석담의 막쌓기가 빗쌓기로 변형되고 찰쌓기는 메쌓기로 바뀌어 경관적, 구조적 문제를 야기하였다. 또한 기초부에 시멘트 모르타르층이 시공되어 자연석 메쌓기로 유도했던 우수의 흐름을 막아버렸다. 셋째, 이러한 정비 양상은 주거공간에 배치된 옛 담장의 속성상 소유주가 일상적 훼손에 대한 비전문적 보수를 반복하고, 문화재 지정으로 인하여 정비를 담당한 수리업체가 지역 재료를 수급하기 어려우며, 옛 담장에 대한 차별성있는 수리시방서가 적용되지 않는 환경에서 기인한다고 판단된다.