• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.235-240
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• 2008

Since urban railway transit is one of the most essential transportation systems, its power facilities must ensure high reliability and safety. Currently, urban railway operating organizations perform TBM (Time Based Maintenance) on power facilities. However, in order to improve management efficiency and system safety, CBM (Condition Based Maintenance) is preferred. Among various power facilities, mold transformers has been chosen as the object of study since it is widely used for the purpose of minimizing volume and weight, and due to safety against fire. In this paper, various transformer failure cases due to electric, thermal, mechanical and environmental factors have been collected and analyzed. In addition, investigation on national and international condition based maintenance cases and the characteristics of sensors widely used for transformer monitoring has been performed to suggest the optimal condition based maintenance technique for urban railway systems.

• 항공우주의학회지
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• 제30권3호
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• pp.91-94
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• 2020

The coronavirus infectious disease-19 (COVID-19) pandemic has had a profound impact on the aviation industry. In order to overcome this crisis, airlines have made their efforts in various fields. Therefore, we tried to summarize these efforts of airlines. It is also essential to keep aircraft that have been in landing for a long time in optimal condition. In this paper, we tried to find out about efforts to maintain landing aircraft and maintenance of personnel. Through such constant care, airlines will be able to quickly respond to increasing aviation demand when the infectious disease situation is stabilized in the future. Finally, airlines and passengers must make several efforts to ensure that passengers are free from COVID-19 while traveling by air. These include general precautions to prevent infection, separation of airline personnel and passengers, changes in seat assignments and in-flight services, periodic aircraft disinfection, and prevention of in-flight infections.

• 한국전통조경학회지
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• 제33권2호
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• pp.12-20
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• 2015

수정동 원림은 조선중기 고산 윤선도에 의해 조영된 곳으로 국문학적으로나 정원사에 있어 중요한 정원유산 이지만 최근 주변 개발로 인한 외부요인에 의한 훼손우려와 오랫동안 방치된 결과 정원 내부의 훼손이 진행되고 있어 대상에 대한 신중한 조사와 분석을 통한 정비계획이 요구된다. 본 연구의 목적은 한국 전통정원 유산인 수정동 원림을 대상으로 진정성 있고 신중한 정비방향을 수립하는 것이다. 연구의 방법으로 지역주민과 전문가들의 인터뷰와 자문, 문헌고찰, 현장조사와 정밀측량, 전문가집단의 참여를 통한 현장 고증 등을 실시하였다. 연구 결과는 다음과 같다. 첫째, 유구에 대한 핵심 권장 검토 발굴 구역을 제시하였다. 둘째, 인위적으로 조영된 환경을 대상으로 고산 당대 조성 혹은 명명된 유구와 조성시기 확인이 요구되는 유구로 구분하여 정비내용을 제시하였다. 셋째, 자연지형 요소에 대해서는 식생정비계획과 활용측면에서 간단한 시설 도입을 제시하였다. 마지막으로 고산이 정원을 즐기고 이용했을 것으로 추정되는 공간들을 중심으로 구체적인 동선과 관련 정비내용을 제시하였다.

• 한국지반환경공학회 논문집
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• 제14권3호
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• pp.35-40
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• 2013

일반적으로 동결대상지역에 설치되는 지반구조물은 동결피해에 대한 별도의 대책을 필요로 한다. 그러나 국내의 경우 터널, 옹벽 등과 같은 지반구조물에 대한 동결피해 조사 및 사례보고가 거의 이루어지지 않고 있어, 이를 저감시키기 위한 연구는 매우 미미한 실정이다. 이러한 이유로 국내의 구조물 관련 설계기준도 특별하게 이를 규정화하고 있지 않다. 본 연구에서는 터널, 비탈면, 옹벽의 동결피해에 대한 현장조사 및 1종, 2종 시설물에 대한 약 40여 년간의 지반구조물 유지관리 이력을 분석하여 구조물 설치지역의 기온에 따른 구조물의 유지관리 특성을 파악하였다. 그 결과 우리나라에서 동결깊이가 약 120cm 이상이고, 기온이 비교적 낮은 강원 산간지역 및 강원 북부, 경기 북부지역의 지반구조물은 기온이 비교적 따뜻한 타 지역과 달리 훨씬 더 오랫동안 보수보강을 필요로 하는 것으로 분석되었다. 이로부터 국내 동결피해 대상지역에 설치되는 구조물에 대한 설계기준 개정의 필요성을 제안하였다.

• 한국철도학회논문집
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• 제15권5호
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• pp.459-466
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• 2012

기존의 철도교량 유지관리체계는 주로 정보누락, 문서위주 관리 및 유선기반의 정보수집 등으로 인하여 다양한 현장의 환경변화에 실시간 대응이 곤란하여 능동적인 철도교량 유지관리 전략 수립에 제약을 갖고 있다. 본 연구에서는 유비쿼터스 기반의 철도교량 유지관리 정보운용체계 구축을 위한 실무 활용모형과 건설 생애주기의 통합 정보관리체계인 BIM (Building Information Modeling) 개념을 적용하여 유지관리 통합 운용모형을 제안하고 있다. 이의 개발 및 실무적 적용의 타당성 확보를 위해 설문분석에 의한 정량적 평가를 수행하였다. 최근 철도교량의 지능형 유지관리 운영체계가 확대될 것을 고려하면, 본 연구의 제안사항은 운영체계 구축을 위한 통합 프레임워크로 활용될 수 있을 것이다.

• 대한토목학회논문집
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• 제39권1호
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• pp.135-146
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• 2019

본 논문에서는 베이지안 추론법을 이용한 교량 실제 운영단계에서의 예방적 유지관리 전략 수립 기법을 제안하였다. 제안된 기법은 모니터링의 불확실성을 고려하여 실제 대상 교량의 상태 변화를 높은 확률로 예측할 수 있다. 실제 공용 중인 교량에 제안된 기법의 적용성을 검토함과 동시에, 손상이 발현된 후 유지보수 조치계획을 수립하는 현행 유지관리체계와 비교하여 유지관리 비용 효율성 측면에서 유리함을 분석하였다. 제안된 기법을 이용하여 기존 유지관리방법의 한계를 극복하고, 공용 중인 교량의 실질적인 유지관리체계 수립을 위한 교량 유지관리 의사결정에 활용할 수 있을 것으로 기대한다.

• 한국환경과학회지
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• 제16권8호
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• pp.973-983
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• 2007

The eco-hydrologic effects of maintenance water supply on Oncheon stream are studied using hydrologic, hydraulic and ecologic models. SWMM (Storm Water Management Model) is used for long-term simulation of runoff quantity and water quality from Oncheon stream watershed. Using the output hydrologic variables from SWMM, HEC-RAS (River Analysis System) is then used to simulate the hydraulics of water flow through Oncheon stream channels. Such hydrologic, hydraulic and water quality output variables from SWMM and HEC-RAS are served as input data to execute PHABSIM (Physical Habitat Simulation) for the purpose of predicting the micro-habitat conditions in rivers as a function of stream flow and the relative suitability of those conditions to aquatic life. It is observed from the PHABSIM results that the weighted usable area for target fishes has the maximum value at $2m^3/s$ of instream flow. However, mid and down stream areas that have concrete river bed and covered region are unsuitable for fish habitat regardless of instream flow increment. The simulation results indicate that the simple maintenance water supply is limited in its effect to improve the ecological environment in Oncheon stream. Therefore, it is imperative to improve water quality and to recover habitat conditions simultaneously.

• 한국도로학회논문집
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• 제14권5호
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• pp.31-45
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• 2012

PURPOSES: In Korea, rapid maintenance of distressed concrete pavement is required to prevent traffic jam of the highway. Asphalt concrete overlay has been used as a general maintenance method of construction for aged concrete pavement. AC overlay on existing concrete pavements experience various early distresses such as reflection crack, pothole and rutting, due to different physical characteristics between asphalt overlay and existing concrete pavement. Bonded concrete overlay(BCO) is a good alternative since it has advantages that can reduce various distresses during the service life since overlay material has similar properties with existing concrete pavements. Recently, BCO which uses the ultra rapid harding cement has been applied for maintenance of highway. BCO has advantage of structural performance since it does monolithic behave with existing pavement. Therefore, it is important to have a suitable bond strength criteria for securing performance of BCO. Bond strength criteria should be larger than normal tensile stress and horizontal shear stress occurred by traffic and environmental loading at bond interface. Normal tensile stress and horizontal shear stress need to estimated for the establishment of practical bond strength criteria. METHODS: This study aimed to estimate the bond stresses at the interface of BCO using the three dimensional finite element analysis. RESULTS: As a result of this study, major failure mode and maximum bond stress are evaluated through the analysis of normal tensile stress and horizontal shear stress for various traffic and environmental load conditions. CONCLUSIONS: It was known that normal tensile stresses are dominated by environmental loading, and, horizontal shear stresses are dominated by traffic loading. In addition, bond failure occurred by both of normal tensile stresses and horizontal shear stresses; however, normal tensile stresses are predominated over horizontal shear stresses.

• 한국습지학회지
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• 제3권2호
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• pp.133-142
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• 2001

Growth of cities and an increase in population result in the development-oriented policy, urban streams to lose their natural characteristics and functions by channelization, parking lot construction, and so forth. The streams fall into urban drains, which is the current status of urban streams. Recently, the interest in the stream environment and the ecosystem has been increased, and the efforts have been made to improve the traditional maintenance program for small streams. These efforts lead to the application of the natural recovery systems. This study applied the 240-meter model reach along the Oncheon stream, which locates in Dongrae-gu, Busan city. to analyze the natural recovery system. The efficiency of each system has been analyzed and the future improvements for the systems are presented. The results show that the stream maintenance program should consider the ecological environment. thereby minimizing the environmental effects. When the changes are inevitable, the maintenance program should adopt the methods. which closely simulate the original environmental elements. or are more favorable to the ecosystem.

• 한국주거학회논문집
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• 제19권4호
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• pp.89-96
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• 2008

The environment has played a key role to improve the living condition and develop the industry. In building industries, we should consider the environment and mitigate the environmental affect. For mitigating the its affect, various areas of building technology have been developed and applied into filed work. In addition, the process in applying into field requires to conduct the assessment of the environmental affect and improve its applied technology. A lot of assessment methods are proposed in evaluate the building condition such as post-occupancy evaluation, life cycle management and life cycle assessment. Among these assessment methods, life cycle assessment is effectively utilized the environmental affect in building life cycle. Therefore, this paper aimed at analyzing the energy consumption and $CO_2$ emission in building life cycle, using the life cycle assessment and application of the example in apartment housing. This study shows that the maintenance and the production of building materials stage shares most of the amount of energy consumption and $CO_2$ emission and therefore plays an important role to planning the building in terms of the life cycle. Second, the other stages brings about a very small amount. It is important to decide the building shape and contents to mitigate the environmental affect in terms of material, volume, the pattern of the energy use and others.