• 한국철도학회논문집
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• 제19권1호
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• pp.67-76
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• 2016

아스팔트콘크리트 궤도는 궤도구조에서 유지관리와 경제적 측면에서 많은 장점들을 가지고 있어 최근 많은 관심을 받고 있다. 이와 더불어 개발에 따른 실용성을 효과적으로 검증할 수 있는 방법 또한 제시되어야 한다. 본 연구에서는 기 개발된 아스팔트콘크리트 궤도에서 사용된 아스팔트콘크리트 재료의 탄성 및 점탄성 특성과 주어진 설계 두께를 고려한 수치해석을 통하여 아스팔트콘크리트 궤도에서 발생 가능한 동적특성을 분석하였다. 해석의 불확실성을 줄이기 위하여 3차원 동적해석을 수행하여 실제적인 거동분석이 가능하도록 하였으며, 궤도노반의 영향거리 분석을 통한 최적 모델링 도출과 무한요소 경계조건을 이용하여 반무한지반을 고려하였다. 아스팔트콘크리트 도상을 등방 탄성체로 간주한 기본설계 조건에서의 거동을 점탄성재료 조건과 비교하였으며 동적증폭계수 산정을 통하여 아스팔트 콘크리트 궤도의 향후 설계방향을 제시하고자 하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1195-1200
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• 2008

This study have goal with conceptual design for Offshore Structures of high pressure control valve for localization. Ball valve for development accomplished with flow analysis based on provision of ANSI B16.34, ANSI B16.10, ANSI B16.25 In order to localize the Offshore Structures high pressure control valve. Numerical simulation using CFD(Computational Fluid Dynamic) in order to predict a mass flow rate and a flow coefficient form flow dynamic point of view. The working fluid assumed the glycerin($C_3H_8O_3$). The valve inlet and outlet setup a pressure boundary condition. The outlet pressure was fixed by atmospheric pressure and calculated until increasing 1bar to 10bar. CFD analysis used STAR-CCM+ which is commercial code and Governing equations were calculated by moving mesh which is rotated 90 degrees when ball valve operated opening and closing in 1 degree interval. The result shows change of mass flow rate according to opening and closing angle of valve. Flow decrease observed open valve that equal percentage flow paten which is general inclination of ball valve. Relation with flow and flow coefficient can not be proportional according to inlet pressure when compare with mass flow rate. Because flow coefficient have influence in flow and pressure difference. Namely, flow can be change even if it has same Cv value. The structural analysis used ANSYS which is a commercial code. Stress analysis result of internal pressure in valve showed lower than yield strength. This is expect to need more detail design and verification for stem and seat structure.

• 복식문화연구
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• 제22권2호
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• pp.290-299
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• 2014

This research sought to analyze the characteristics of breast movement at the treadmill activity levels. It also examined the effect of wearing a sports bra in reducing breast displacement. The subjects for the data collection were females in their 20s (n=2) with C-cup size breast. The experimental conditions were three different moving speeds (4 km/h, jogging: 7 km/h, and sprinting: 10 km/h) and two types of sports bras. Three dimensional breast displacement was measured. The displacement of the right nipple point was measured with a 3D motion analyzer. The results show that the breasts were greatly displaced from the walking speed (4 km/h) when subjects did not wear any bra. Whereas their breast displacement distance decreased remarkably when they wore sports bras. The nipple point moved 42~44 mm in the vertical direction at walking speed with naked condition. But it was reduced by 80% after wearing sports bras. When subjects running (7 km/h, 10 km/h) without any bra, the nipple point moved 122~141 mm. However it was reduced by 60~70% when they wore sports bras. The apartment time (time delay) between at the highest point of the upper body and the nipple was 0.25 seconds at the running speeds (7 km/h, 10 km/h) without wearing any bra. After wearing sports bras, the time delay was cut to 0.06~0.12 seconds. These results implies that without wearing any bra the skin surrounding the breasts might be seriously pulled at running activity. The functional sports bra suppress breast movement. It might prevent the sagging of breasts by preventing the damage of the Cooper's ligaments.

• Nuclear Engineering and Technology
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• 제32권2호
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• pp.128-141
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• 2000

The critical heat flux (CHF）experiments have been carried out in a wide range of pressures for an internally heated vertical annulus. The experimental conditions covered ranges of pressures from 0.57 to 15.01 MPa, mass fluxes of 0 kg/$m^2$s and from 200 to 650 kg/$m^2$s, and inlet subcoolings from 85 to 413 kJ/kg. The characteristics of the present data and the effect of pressure on CHF are discussed. Most of the CHFs were identified to dryout of the liquid film in the annular or annular-mist flow. For the mass flux of 200 kg/$m^2$s, there were the indications that the CHF occurred at the transition from annular to annular-mist How in the pressure range of 3~10 MPa. For the mass fluxes of 550 and 650 kg/$m^2$s, the CHFs had a maximum value at a pressure of 2~3 MPa, and the pressure at the maximum CHF values had a trend moving toward the pressure at the peak value of pool boiling CHF as the mass flux decreased. The CHF data under a zero mass flux condition indicate that both the effects of pressure and inlet subcooling on the CHF were smaller, compared with those on the CHF with net water upward flow.

• 한국수자원학회논문집
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• 제53권6호
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• pp.451-461
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• 2020

급격한 도시화로 인한 도시홍수가 최근 들어 자주 발생하고 있다. 본 연구에서는 도시홍수를 방어하기 위해 국내최초로 건설중인 신월 빗물저류배수시설을 대상으로 수리모형실험을 실시하였다. 총 55가지 시나리오에 대한 실험을 실시하였는데 그 중 19가지 시나리오에서 월류가 발생하였다. 또한 월류가 발생한 시나리오에 대한 비디오 분석결과, 불규칙 단파가 이동하면서 시설 내 압축공기를 배기시키는 과정에 월류가 발생하는 것으로 분석되었다. 본 연구 결과를 바탕으로 향후 연속강우에 대한 신월 빗물저류배수시설에 대한 안정적 운영을 위해서 완전배수 또는 만관상태를 유지하는 것이 유리할 것으로 판단되고 유입유량의 크기, 월류, 불규칙 단파간의 상관관계에 대한 추가 연구가 필요할 것으로 판단된다.

• 한국정보시스템학회:학술대회논문집
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• 한국정보시스템학회 2000년도 추계학술대회
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• pp.26-31
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• 2000

It is said that the focus of managing venture business is currently moving from technology competition to management competition. By the way, the software venture business(SVB) has some weak points in its structural composition and itematization and no professional personnel in other several sections except technology development section. In addition, such basic functions as technology and R & D, finance and accounting, marketing required to the management of business are concentrated on only one man, its representative director. Therefore, this study aims to provide the basic data useful to the establishment of governmental policy in information and communication, to the rearing of the SVB by a local government related to the software, and to the administration of SVB by investigating the actual conditions. This study attempts to examine the literature on venture business and software industry, and its management with a questionnaire about the actual conditions of managing the SVB. The questionnaire is given to 527 local enterprises belonging to the Software Industry Association and to 171 enterprises in the Software Center. This study compromises the characteristics of the SVB, the actual conditions of its technology and R & D, finance and accounting, and marketing. The characteristics of the SVB are classified into categories such as the stage of its growth(the stage of its seed and start-up, the stage of tis development and growth, the stage of its stability and maturity) and the main business(the system integration, the software development for contract, the package software development service, the software-related service). Additionally, the study attempts to analyze positively the actual condition of its management after classified by the areas of business profile, its general management, its technology development, its finance and accounting, and its marketing The result of this study is found that the SVB has a lot of troubles in part of marketing and finance & accounting activity as well as general management. The SVB realizes the importance of the technology development rather than that of management activity including marketing activity. So we expect this study can assist the SVB to establish the business guidelines for own management plans.

• 대한가정학회지
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• 제26권3호
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• pp.135-152
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• 1988

The purpose of this study was to survey the improvement activities for the apartment house ; and to examine the relationship between apartment residents and their housing improvement activities in order to present some informations for the further studies and plans of apartment design and housing policy. Library and questionnaire survey methods were used in this research. the sample was taken from 102 housewives living in the apartments over 45 pyong (1602 sq. ft.), in Seoul, Data were analyzed with the SPSS using frequency, percentage, chi-square test, F-test, Duncan's multiple range test, η2, and C2. The results were as follows: 1. It was found that residents had experienced with 3.6 kinds of housing improvement activities. Living rooms, dining rooms, and kitchens in family living areas ; balconies and utility rooms in utility areas were improved for the physical convenience and quality of living. 2. This survey indicated that apartment residents evaluated thier housing condition as high, except storage spaces and outdoor noises. 3. About 80% of respondents were expected to live continuously in the current apartments because they were satisfied with the size of thier residences, However, they wanted to improve the inside of the entire apartment, especially bathrooms. 4. Variables which had a significant relationship in housing improvement activities in the past were the length of residence, the expected length of residence, and the characteristic of residence. 5. The expected length of residence, and the characteristic of residence were found to be effective variable for evaluating the current residence. 6. Finally, the expected length of residence, and the characteristic of residence were significant variables of the housing plan in the future. Housing improvement activities were prevalent recently and expected to be continued in the future. It can be said, therefore, that apartment residents have a long -term plan to live in one place rather than moving out ever two-three years.

• 한국해양공학회지
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• 제22권3호
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• pp.8-17
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• 2008

Wrenching climatic changes due to ecocide and global wanning are producing a natural disaster. Coastal zones have been damaged by typhoons and accompanying storm surges. Severe waves, and destruction of the environment are adding to the severity of coastal disasters. There has been an increased interest in these coastal zone problems, and associated social confusion, after the loss of life and terrible property damage caused by typhoon Maemi. Especially if storm surges coincide with high ticks, the loss of life and property damage due to high waters are even worse. Therefore, it is desirable to accurately forecast not only the timing of storm surges but also the amount water level increase. Such forecasts are very important from the view point of coastal defense. In this study, using a numerical model, storm surge was simulated to examine its fluctuation characteristics for the coastal area behind Masan Bay, Korea. In the numerical model, a moving boundary condition was incorporated to explain wave run-up. Numerically predicted inundation regimes and depths were compared with measurements from a field survey. Comparisons of the numerical results and measured data show a very good correlation. The numerical model adapted in this study is expected to be a useful tool for analysis of storm surges, and for predicting inundation regimes due to coastal flooding by severe water waves.

• 한국전산구조공학회논문집
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• 제22권4호
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• pp.335-341
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• 2009

본 논문에서는 MLS기반 유한요소에 대한 현재 개발상황에 대한 개관과 향후 예상할 수 있는 응용분야에 대한 제안을 하였다. 이동최소제곱근사를 이용하여 형상함수를 생성하는 MLS기반 유한요소는, 요소의 경계에서 기존 유한요소의 성질-크로네커 델타 조건-을 가지면서도 기존 요소가 갖지 못했던 임의의 절점 추가가 자유롭다는 장점이 있어 다양한 변절점 요소로의 개발이 이루어져 왔다. 선형 또는 이차형상함수를 갖는 2차원 변절점요소 뿐 아니라, 균열선단과 균열면을 포함하고 있는 2차원 균열요소와 3차원에서의 제한적인 변절점요소 등이 개발되어 다양한 불연속성 문제에 적용 가능함이 입증되었다. 이러한 MLS기반 유한요소는 향후 2차원 변절점 3각요소, 2차원 삼각균열요소, 변절점 쉘요소, 균열 쉘요소, 마칭큐브알고리즘에 적합한 3차원 다면체요소로의 개발이 가능할 것으로 예상되며, 본 논문에서는 그 일례로 3차원 다면체요소를 이용한 대퇴골의 요소망 생성을 보였다.

• 대한조선학회논문집
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• 제29권4호
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• pp.104-113
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• 1992

압력이 차 있는 백이 물에 부분적으로 잠겨서 동요하고 있을 때의 유체역학적 문제가 다루어졌다. 쌍동형 공기부양선(SES)의 선미에는 공기의 유출을 막기위해 공기압이 채워진 백을 설치하고 있는데, 백에 의한 힘이 종동요에 큰 영향을 미친다. 백의 모양은 안과 밖의 압력차에 의해서 결정되므로, 유체동압력을 구하면 백의 모양을 알 수 있는데, 백의 모양변화를 알아야지만 유체동압력을 구할 수가 있다. 따라서 백 표면에서의 경계조건의 형태는 자유표면 경계와 더불어서 움직이는 경계가 된다. 본 논문에서는 이 문제를 정식화하고 선형화를 하였다. 또한 백이 동요할 때의 방사문제에 대한 계산예를, 백을 강체로 가정했을 때의 비교하여, 보여주고 있다. 여러가지의 백내의 압력값, 또 물에 잠긴 깊이에 대해서 계산이 이루어졌다.