• 항공우주기술
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• 제12권2호
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• pp.57-63
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• 2013

정지궤도에서 운용되는 많은 위성들이 통신방송을 목적으로 하고 있기 때문에 전력 요구량이 크고 이에 따라 대용량의 태양전지판이 필요하다. 최근에는 정지궤도에 통신방송 이외에 기상을 비롯한 지구환경 관측을 목적으로 하는 위성들이 개발되는 추세이다. 이러한 관측 위성의 탑재체는 감지기의 열환경 조건이 매우 중요하기 때문에 열원으로 작용되는 태양전지판을 제거하고 대신에 자세 안정도를 확보하기 위해 붐을 사용한다. 다른 방법으로 모멘텀 용량이 큰 휠을 장착하여 비대칭 태양전지판 형상으로 인해 태양에 의한 외란을 휠이 흡수하는 자세제어 방식을 사용하고 있다. 본 논문에서는 완벽한 비대칭 태양전지판 형상의 천리안위성에서 사용하고 있는 휠배치와 그에 적합한 휠모멘텀조정에 관하여 분석하고 현재 운용되고 있는 텔레메트리를 통해 그 결과를 검증하였다.

• 대한예방한의학회지
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• 제17권1호
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• pp.27-50
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• 2013

Objectives : The aim of this study is to analyze the research trend focusing on well-being studies in Korea. Through this study, the researchers attempt to explore the research trends of the Yangseng(養生) and well-being in Traditional Korean Medicine. Methods : Well-being as a key word was searched on representative domestic databases of articles. The researchers collected the articles of journals published from 1980 to 2012. Finally 2,413 articles of well-being were selected. Results : Domestic studies of well-being had been increased steadily since the 1990s and they were greatly increased after the 2000s boom of well-being. Before 2000s, the mainstream of well-being studies was to analyse the correlation among the variables associated with quality of life in medicine. After the boom of well-being, the number of researches has been increasing significantly, since 2000s. Various methodologies of well-being studies(especially related various goods and services) have also been developed in the field of academia. Recently the concept of well-being has been evolving into LOHAS, wellness, healing, well-dying and etc. Conclusions : In order to handle the new wave of society and medicine, new health concept of Traditional Korean Medicine should be developed through Korean unique ideas of Yangseng.

• 상하수도학회지
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• 제27권2호
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• pp.261-272
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• 2013

Algae boom (Red tide) in south coastal area of Korea has been appeared several times during a decade. If algae boom appears in the desalination plant, media filter and UF filter are clogged quickly, and the plant should be shutdown. In general, Algae can be removed from water by flotation better than by sedimentation, because of the low density of algal cell. The purpose of this study conducts the CFD simulation of DAF flotation basin to apply the design of the dissolved air flotation with ball filter in the Test Bed for SWRO desalination plant. In this study, Eulerian-Eulerian multiphase model was applied to simulate the behavior of air bubbles and seawater. Density difference model and gravity were used. But de-sludge process and mass transfer between air bubbles and seawater were ignored. Main parameter is hydraulic loading rate which is varied from 20 m/hr to 27.5 m/hr. Geometry of flotation basin were changed to improve the DAF performance. According to the result of this study, the increase of hydraulic loading rate causes that the flow in the separation basin is widely affected and the concentration of air is increased. The flow pattern in the contact zone of flotation basin is greatly affected by the location of nozzle header. When the nozzle header was installed not the bottom of the contact zone but the above, the opportunity of contact between influent and recycle flow was increased.

• 기술사
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• 제16권3호
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• pp.5-23
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• 1983

On the Seoul Metropolitan Subway Construction of No. 3, 4 Line, the total length is 57 Km and it is now undergoing almost 55％ progress. The working method is classified into Open Cut of 70% and the rest of 30% tunnelling method in the 48 job site. Above tunnelling method is execute by American Steel Support System and the rest of 10 job site carried out by New Austria Tunnelling Method. This paper describes Blasting Standardizations works on the above Tunnelling ' Open Cut Method under big slogan, first safety, second execution. As a superintendent, I strived standardization of works with Better powder, Better Drills ' Better Pattern. Geological structure of Seoul area is composed by Jurassic Granite and also the above rockgroup are over burden by Alluviums as a Unconformity. First of all, I carried out the standard amount of powder and burden through experimental standard blasting by each powder as following Blasting works in the subway construction is surrounding shop Building, under pass the city river and also under pass highest building basement floor. I made allowable Blasting Vibration Value by West-Germany Vornorm DIN 4150, Teil 3 and should measure each blasting works as fellows all of powder is used basically Low-Gravity and Low Velocity such as Slurry, Ammonium Nitrate ' Finex I, II. for Smooth Blasting Instead of Gelatin Dynamite. Electric Detonation Cap is used basically M/S Delay Cup instead of Electric delay ' Simultaneous cap. I applied following formula V=KW3/4 $D^{-2}$ V=Particle Velocity (Cm/sec) K=Ginh Huh's Value W=Delay Charge (Kg) D=Distance(m) In the Open Cut, within 1m distance from H-pile I made to use the Concrete breaker, as following V=7W/$^{0.5}$V/$^{-1.75}$ On the Concentrate Building area, I advise to use Light class drill ø36m Bit and advance 1.1m per round blasting the three boom jumbo drill over ø45mm used only suburb of city.e Light class drill ø36m Bit and advance 1.1m per round blasting the three boom jumbo drill over ø45mm used only suburb of city.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.225-229
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• 2009

International construction market has been open to other countries, and it derives the development of our overseas construction industry quantitatively as well as qualitatively. Until now, the major companies have an absolute majority in the overseas construction market, and the small and medium enterprises have had difficulty to get a leadership in the international construction market because of the lack of the technical expertise and the capital strength. Especially in the Middle East Asia, our construction companies has touched off a boom, so our market share also has grown, which derived from the up toward ratchet oil prices and a worldwide boom in real estate development. The small and medium enterprise minority have recognition that the overseas construction market is the major company's native territory. But Data from the existing researches and many statistics indicate the most companies tend to underestimate the capacity and international competitiveness of the small and medium enterprises. As a matter of fact, hundreds of small and medium enterprise cut a conspicuous figure in overseas market. Consequently, it is indispensable to overcome the international financial crisis by revitalizing our overseas construction industry which obtains excellent results in international market. this study suggested the ways to expand overseas bonding capacity of Korean financial institution. This study proposed the Korean government to allow Construction Guarantee (former Korea Construction Financial Cooperative) to deal with foreign exchange so that Construction Guarantee will underwrite the overseas construction bond.

• 대한조선학회논문집
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• 제50권1호
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• pp.33-40
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• 2013

Since most of yacht sails are made of thin fabric, they form cambered sail shape that can efficiently generate lift power by aerodynamic interaction and by external force delivered from supporting structures such as mast and boom. When the incident flow and external force alter in terms of volume or condition, the shape of sail also change. This deformation in shape has impact on the peripheral flow and aerodynamic interaction of the sail, and thus it is related to the deformation of the sail in shape again. Therefore, the precise optimization of aerodynamic performance of sail requires fluid-structure interaction (FSI) analysis. In this study, the simplified sail without camber was under experiment for one-way FSI that uses the result of flow analysis to the structural analysis as load condition in an attempt to fluid-structure interaction phenomenon. To confirm the validity of the analytical methods and the reliability of numerical computation, the difference in deformation by the number of finite element was compared. This study reproduced the boundary conditions that sail could have by rigs such as mast and boom and looked into the deformation of sail. Sail has non-linear deformation such as wrinkles because it is made of a thin fabric material. Thus non-linear structural analysis was conducted and the results were compared with those of analysis on elastic material.

• KIEAE Journal
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• 제10권5호
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• pp.101-108
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• 2010

It is estimated that the elderly will constitute 24.3% of the entire Korean population in 2030, when about 7,125,000 baby boomers reach retirement age. Therefore, this aging phenomenon might be the most urgent issue facing Korean society. The baby boom generation shows a strong tendency to dispose of existing residences or move into new housing after retirement, thereby exerting enormous impacts on social and economic sectors as well as the housing market. Against this backdrop, this study aims to identify both factors and patterns behind baby boomer retirees' post-retirement housing transfer trends. To this end, a survey is undertaken here with respect to those baby boomers living in Gangnam-gu and Seocho-gu with actual housing transfer plans in the foreseeable future, and who can act as a practical consumer group for the future housing market. This study verifies baby boomers' diverse preferences for housing type. Their preference for apartment houses still remains high in every situation, and this has significant implications for changed preferences of other housing types considering that most of the survey respondents currently reside in apartment houses. According to the survey, there are more than 80 kinds of baby boomers' housing transfer patterns, which demonstrates that more than half of the survey respondents pursue different housing mobility plans. When it comes to the factors behind their housing selection, the baby boom generation shows a strong preference for physical factors. However, environmental and psychological factors gain more momentum under unfavorable circumstances, while social factors play a decisive role in their housing selection in categories such as 'couple/deteriorating health' and 'single/healthy'.

• 한국안전학회지
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• 제35권5호
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• pp.1-8
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• 2020

Mobile elevating work platforms (MEWPs) consist of a work platform, extending structure, and chassis, and are used to move persons to working positions. MEWPs are useful but are composed of pieces of equipment, and accidents do occur owing to equipment defects. Among these defects, accidents caused by the fracture of bolts fixed to the extension structure and swing system are increasing. This paper presents a failure analysis of the fixing bolts of MEWP. Standard procedure for failure analysis was employed in this investigation. Visual inspection, chemical analysis, tensile strength measurement, microstructural characterization, fractography analysis by Optical Microscope(OM) and Scanning Electron Microscopy(SEM), and finite element analysis (FEA) were used to analyze the failure of the fixing bolts. Using this failure analysis approach, we found the root cause of failure and proposed a means for solving this type of failure in the future. First, the chemical composition of the fixing bolt is obtained by a spectroscopy chemical analysis method, which determined that the chemical composition matched the required standard. The tensile test showed that the tensile and yield strengths were within the required capacity. The stress analysis was carried out at five different boom angles, and it was determined that the fixing bolt of MEWP can withstand the loads at all the boom angles. The outcomes of the fatigue analysis revealed that the fixing bolt fails before reaching the design requirements. The results of the fatigue analysis showed primarily that the failure of the fixing bolt was due to fatigue. A visual inspection of the fractured section of the fixing bolt also confirmed the fatigue failure. We propose a method to prevent failure of the fixing bolt of the MEWP from four different standpoints: the manufacturer, safety certification authority, safety inspection agency, and owner.

• 한국산학기술학회논문지
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• 제12권4호
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• pp.1833-1843
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• 2011

최근 우리사회는 사회경제적으로 급격한 변화를 맞이하고 있다. 세계에서 가장 빠른 속도로 고령화가 진행되는 가운데 베이비붐 세대의 퇴직이 본격화되고 있다. 이러한 베이비붐 세대는 지난 70~80년대 우리경제발전의 주역으로 퇴직 후 재취업의 현실적 어려움과 미흡한 노후준비 및 이들의 복지와 의료문제 등이 국가적 현안으로 대두되고 있다. 이에 정부는 금년부터 시니어의 강점을 적극 활용하여 생산적 경제활동 참여를 위해 시니어창업육성정책을 수립하고 있다. 그러나 이러한 시니어창업의 중요성에도 불구하고 시니어의 욕구와 시니어창업의 구체적인 특성을 규명하는 연구는 전무한 실정이다. 이에 본 연구에서는 시니어의 구체적인 특성과 창업의도 및 성공창업의 핵심역량인 기업가정신에 미치는 영향을 실증적으로 분석하고 시니어창업의 활성화 방안을 제시하였다.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 춘계학술대회 및 창립 30주년 심포지엄(논문집)
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• pp.311-316
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• 2006

본 연구는 75m/s의 풍하중이 컨테이너 크레인에 작용할 때, 붐 형상 변화에 따라 풍하중이 컨테이너 크레인의 구조적 안정성에 미치는 영향을 풍동실험을 통하여 분석하여 컨테이너 크레인의 내풍설계 시 필요한 자료를 제공하기 위해 수행되었다. 풍동실험에 적용된 데이터 수집조건은 상사법칙에 준하여 설정되었으며, 컨테이너 크레인 모형, 풍속 및 시간의 축척률은 각각 1/200, 1/13.3 및 1/15로 하였다. 그리고 실험은 $11.25m^2$의 측정부 단면을 갖는 개방형 대기경계층풍동을 사용하여 수행하였다. 풍향에 따른 컨테이너 크레인의 풍력계수 및 전도모멘트계수가 조사되었으며, 풍하중에 의해 각 지지점에서 발생되는 전도력이 분석되었다.