• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.458-463
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• 2000

Recently, there are increasing much concerns about repair and rehabilitation works for aged Concrete Structures which had been constructed on around the 1970's for rapid economic growth in Korea. In particular, it is believed that there are many aged concrete slabs for Highway bridges in these days. Thus new construction method of concrete slabs are strongly needed to minimize the traffic congestion during the repair works. The objective of this research is to develop the new constructional method of concrete slab in bridge structure, which can contribute to minimize the traffic congestion to be occurred during the repair and rehabilitation works of aged concrete slab, and can also assure the reliable quality through the minimization of in-situ works at the site. I-beams with punch holes will be manufactured in accordance with the specification in the factory, and will be preassembled into the panel. After erecting the preassembled panels in the site, concrete will be poured into the slab panel. This research is to investigate physical properties of I-Beam with punch holes itself, and then to investigate structural properties of assembled I-Beam panels through static and fatigue test, of which result can be utilized for the development of the new constructional method for concrete slab in bridge structure.

• 한국실내디자인학회논문집
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• 제25권3호
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• pp.82-89
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• 2016

This study investigated the preservation status of wooden architectural heritages, designated as Chungcheongbuk-do designated heritage in Jecheon. The purpose of this paper is to find the damage cause and the preservation method of wooden architectural heritages. It was conducted using the research methods of the existing literature and field survey to compare a current status of wooden architectural heritages. The result are as followings. Firstly, it was found the problems of a break, a damage, etc. in the platform and the problems of a cracking, an exfoliation, a corrosion, a warp, etc. in the wall. And, it was found a cracking of the beam(梁) and a roof tile(瓦), a falling of Angto(仰土), a sagging roof, etc. in the roof. Secondly, the damage causes of wooden architectural heritages were mostly caused by the physical limitations of the materials. And, it was caused by a rainwater, a subsidence of ground settlement, a destruction of waterproof membrane, etc. Lastly, the repair methods are making a quicklime layer in the soil mound on a cracking and an exfoliation part, a resin treatment or strut operation on a corrosion part of column, etc.

• 한국군사과학기술학회지
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• 제15권6호
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• pp.738-745
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• 2012

Aircraft battle damage repair(ABDR) is emergency repair method for the damaged aircraft in battle field. The main purpose of the ABDR is to increase the readiness of fighter aircraft during wartime. While many studies have been conducted to develop ABDR method, few efforts have focused on evaluation of damage and determination of the size of hole caused by enemy's anti-aircraft artillery attack. The aim of this study is essentially to quantify damage of aircraft wing attacked by anti-aircraft artillery. The computer simulations was performed to accomplish this goal. A number of simulations have been carried out to compare size of damages under various attack conditions. In conclusion, it was revealed that the size of damage varied depending on the type and direction of cannonball. Furthermore, in this paper, the proper path sizes are suggested for different damage conditions.

• 산업경영시스템학회지
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• 제45권3호
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• pp.18-30
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• 2022

Predicting remaining useful life (RUL) becomes significant to implement prognostics and health management of industrial systems. The relevant studies have contributed to creating RUL prediction models and validating their acceptable performance; however, they are confined to drive reasonable preventive maintenance strategies derived from and connected with such predictive models. This paper proposes a data-driven preventive maintenance method that predicts RUL of industrial systems and determines the optimal replacement time intervals to lead to cost minimization in preventive maintenance. The proposed method comprises: (1) generating RUL prediction models through learning historical process data by using machine learning techniques including random forest and extreme gradient boosting, and (2) applying the system failure time derived from the RUL prediction models to the Weibull distribution-based minimum-repair block replacement model for finding the cost-optimal block replacement time. The paper includes a case study to demonstrate the feasibility of the proposed method using an open dataset, wherein sensor data are generated and recorded from turbofan engine systems.

• 한국표면공학회지
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• 제56권4호
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• pp.283-287
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• 2023

The structures for road safety are guard rails that protect the cars and passengers. If an accident occurs on the roads after a long period of installation, it may escalate into a major disaster. In order to repair many guard rails, the existing repair method of replacing them with new ones requires enormous financial resources. To solve this problem, the G-SAVE method was developed to repair the guard rail without replacing them. This method removes the rust on the surface of the guard rail and then performs ambient-dip galvanizing coating on it without replacing the new ones. No studies or reports have yet been made on the risk assessment of harmful substances, vehicles for these entire processes. Therefore, this paper focuses on risk assessment using the PHA (Preliminary Hazard Analysis) technique and conducts risk assessment for concept design stage of the coating vehicles.

• 대한구순구개열학회지
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• 제15권2호
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• pp.61-68
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• 2012

Cleft lip and palate is the most common congenital facial malformation and has a significant developmental, physical, and psychological impact on those with the deformity and their families. When treating the patients with unilateral cleft lip, many surgeons adopt the rotation advancement flap method originally developed by Millard, or the triangular flap technique developed by Tennison, Randall or the modifications of these techniques. Among these, Millard's rotation advancement flap method has its advantage in designing the flap using the patient's anatomic landmarks. For performing this rotation advancement technique, skillful operation is needed to obtain esthetically satisfactory results. Vomer flap sometimes is used to repair anterior hard palate in complete cleft lip and palate patients. Vomerine tissue is readily available in the vicinity of the palatal defect and elevation of the vomerine flap is relatively simple procedure. In this article, we will introduce the comprehensive vomer flap technique conjunction with primary lip closure and review the comparative studies of the outcome of simultaneous repair of cleft lip and cleft hard palate with Millard's rotation advancement method and vomer flap.

• Archives of Plastic Surgery
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• 제33권1호
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• pp.61-66
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• 2006

The purpose of this study is to introduce the method of palate repair that combines minimal hard palate dissection and radical retropositiong of levator musculature, which was presented by Sommerlad. As this method presents, additional use of the operating microscope enables atraumatic and radical dissection, and it might provide more improved speech function to the patients. A total of 17 patients with cleft palate underwent Sommerlad's method from December 2003 to August 2004. The mean follow-up period was 4.5 months. The use of a microscope provided high quality variable magnification and good illumination at the operating field. Repair was carried out through incisions at the margins of cleft with mucoperiosteal flap elevation. Muscles were rearranged and repaired properly. It was unable to evaluate the improvement of speech because the patients were too young to learn meaningful speech. Average operating time including anesthetic induction time, V-tube insertion and recovery from anesthesia was 2 hours 45 minutes which was not quite different from conventional method's operating time. Oronasal fistula developed in 2 patients of them. One of them was healed spontaneously. As meticulous and radical muscle dissection was possible with Sommerlad's method, we could minimize the trauma to the muscular and neurovascluar structure. In addition, we expect better faculty of speech as a result of this method although longer follow-up time was unavailable.

• 한국건설관리학회:학술대회논문집
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• 한국건설관리학회 2002년도 학술대회지
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• pp.355-358
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• 2002

국내에서 1960년대부터 공동주택의 활발한 보급이 이루어지고 있는 반면, 공동주택의 물리${\cdot}$사회적 성능을 유지하여 수명을 연장시키기 위한 제도 및 표준적 유지관리 기법 등이 마련되지 못하여 시설안전 및 주거환경 문제가 발생하게 되었다. 이러한 현 상황 하에 공동주택의 유지관리를 통하여 주택의 수명을 증진함으로써 주택자원의 효율적인 이용이 시급한 실정이다. 공동주택의 유지관리 업무 측면에 있어 정확한 장기수선계획의 수립과 그에 따른 특별수선충당금 산정은 주택의 조기 노후화를 방지할 수 있다. 하지만 유지관리 행위주체인 주택 관리자들뿐 아니라 유지관리 대상시설물에 거주하는 입주자들에게 있어서 정확한 장기수선계획의 수립과 그에 따른 특별수선충당금의 적립에 관한 필요성 의식이 불충분한 현실이다. 장기수선계획의 미수립은 특별수선충당금의 비합리적인 적립을 허용하는 결과를 초래하고 있다. 따라서, 공동주택의 성능을 최대한 발휘하도록 하여 건물의 경제적 수명을 연장시키기 위하여 정확한 근거에 의한 장기수선계획의 수립과 그에 따른 특별수선충당금산정 방법을 제시하고자 한다.

• 콘크리트학회논문집
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• 제19권5호
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• pp.569-575
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• 2007

철근콘크리트 구조물의 수명 연장 및 기능 보완을 위하여 콘크리트 면의 보수를 실시할 경우 일반적으로 구조적 내력을 고려하지 않는다. 특히, 표면박락 등의 보수에는 단순하게 모르타르 도포만을 이용하여 보수가 완료되므로 별도의 구조적인 보강 성능을 발휘하지 않는다. 그러나 시공성의 향상 및 균열의 억제를 위하여 철망 등의 재료를 사용할 경우 일정부분 보강의 효과를 얻을 수 있을 것으로 예상되며, 특히, 수로 구조물과 같이 교각 간에 놓여지는 구조요소의 경우 하부면의 보수를 실시할 경우 휨 저항성의 증가를 기대할 수 있다. 따라서 본 연구에서는 크리프 철망에 의한 보수를 실시하고 보수 부위 및 보수 두께에 따른 보강 성능을 확인하고자 하였다. 이를 위하여 두께 150mm, 길이 3,000mm, 너비 600mm 슬래브를 제작하고, 상부 부분 보수, 상부 전면 보수, 하부 부분 보수, 하부 전면 보수, 크림프 철망 보강 유무 등 총 8개 실험 유형을 선택하고 이에 대한 휨 보강 성능 실험을 실시하였다. 분석 결과, 크림프 철망을 보강한 실험체에서 보수 재료의 두께가 증가할수록 항복하중 및 파괴하중은 높아지는 것으로 나타났으며, 동일 조건일 경우 하부면의 보수가 휨 하중에 대한 내력을 증가시킬 수 있는 것으로 나타났다. 또한, 휨 하중을 받는 구조물 중 부분 보수만을 실시할 경우 휨 보강 성능은 기대하기 어려운 것으로 나타났다. 결론적으로 크림프 철망에 의한 보수공법 적용 시 휨 저항성의 증가가 있는 것을 알 수 있었다.

• 한국건축시공학회지
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• 제10권2호
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• pp.41-50
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• 2010

본 연구에서는 수선교체이력 자료 및 전문가 의견을 기초데이터로 하고 몬테카를로 시뮬레이션을 활용하여 건축물 수선교체주기에 대한 신뢰성 분석을 가능하게 할 수 있는 모델을 제시하였다. 제시된 모델은 건축물의 경년별 수선교체 시기를 확률적으로 제시하고 건물의 유지관리 계획시 신뢰성분석에 근거한 수선교체시기와 비용수요를 사전에 예측하도록 지원한다. 또한 건물의 소유주체나 유지관리 의사결정권자에게 공통적으로 발생하는 계획상의 많은 리스크를 감소시켜주는 역할을 할 것이다. 더불어 기존건물의 수선교체 이력데이터의 부재로 인해 의사결정에 많은 어려움 겪고 있는 대규모 건물자산의 유지관리책임자가 수선교체소요에 대한 중장기정책 수립시 이에 대한 타당성을 확보할 수 있는 공학적 해법이 제시되었다. 정리하면 크게 다음과 같이 3가지의 연구성과로 나눌 수 있다 첫째, 건축시스템의 발달에 대응할 수 있는 수선교체주기 산정법이 개발되었다. 둘째, 수선교체주기의 리스크를 정량화 시킬 수 있는 확률론적 방법론이 제안되었다. 셋째, 제안된 모델은 건축프로젝트에서 설계자와 시공자가 건물의 생애주기설계에 관한 의사결정을 지원할 수 있는 도구로 활용 가능할 것이다.