• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.2
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• pp.157-164
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• 2017

A parallel slide gate valve (PSGV) is located between the heat recovery steam generator (HRSG) and the steam turbine in a combined cycle power plant (CCPP). It is used to control the flow of steam and runs with repetitive operations such as startups, load changes, and shutdowns during its operation period. Therefore, it is necessary to evaluate the fatigue damage and the structural integrity under a large compressive thermal stress due to the temperature difference through the valve wall thickness during the startup operations. In this paper, the thermal-structural analysis and the fatigue life evaluation of a 16-inch PSGV, which is installed on the HP steam line, is performed according to the fatigue life assessment method described in the ASME B&PVC VIII-2; the method uses the equivalent stress from the elastic stress analysis.

• KIEAE Journal
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• v.7 no.2
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• pp.31-37
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• 2007

Despite of many supportive research to the usefulness of slide evaluation on environment of outdoor lighting, study method of using slides have provoked many discussions of its manifestation of reality of field conditions. This study aims to compare the results of slide survey with that of field survey. Distant view and short range view of nightscape of Seoul were selected. Field measurement of luminance and chromaticity were conducted and questionnaire survey were conducted. Frequency analysis, T-test, factor analysis were conducted. Results shows that distant view and short range view of field survey have better visual atmosphere than slide survey. In addition, slide survey on distant view shows lowest values. Difference between field survey and slide survey on distant view is much bigger than the results of short range view.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.8 no.2
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• pp.13-26
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• 1998

시각암호는 비밀화상을 share라 불리는 암호화된 형태로 분산하는 방법으로서n명의 참여자로 이루어진 잡합 p에 대하여, 각 참여자는 share로 구성된 슬라이드(transparency)를 한장씩 부여받는다. 참여자들의 인가된 부분집합은 슬라이드를 중첩시켜 시각적으로 비밀정보를 복원할 수 있지만, 다른 부분집합은 비밀 정보를 복원 할 수 없다. 이 방법은 비밀정보를 복원라기 위하여 인간의 시각 체계를 이용하므로 컴퓨터를 사용한 복잡한 연산이 필요 없는 이점이 있는 반면에 복원화상의 휘도가 손실되는 단점이 있다. 이논문에서는 참여자의 계층화를 고려한 (2, n) VCS(Visual Cryptography Scheme)를 구성하기 위한 새로운 모델을 제안하고 계층적 접근구조에 의해 휘도를 개선하는 방법을 보인다. 제안하는 방법의 효율을 평가하기 위하여 (2, n) VC로 재구성되는 화상의 휘도를 분석한다. 또한 그 응용으로서 한 장의 슬라이드로 사용자와 시스템 사이에 상호식별이 가능한 메카니즘을 제시한다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.05a
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• pp.310-313
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• 2002

본 연구는 공간특성이 서로 다른 두 공간, 주거/사무공간의 조명환경에 대한 평가구조를 비교 검토하고 각 공간의 행위에 적합한 조명환경을 제시하고자 슬라이드 사진을 이용한 평가실험을 실시하였다. 평가대상 슬라이드수는 주거공간이 28장, 사무공간이 26장이다 실험은 각 공간별로 분위기항목과 행위항목에 대해 각각 실시하였다. 평가항목은 분위기항목이 21가지, 행위항목이 14가지이다. 각 공간의 평정치를 이용하여 인자분석을 실시한 결과, 주거공간과 사무공간 모두 <활동성>,<안정감),<고급감)의 3인자축이 추출되었다. 그러나, 주거공간의 경우는 <활동성>인자축이 평가축을 이루었으며, 사무공간의 경우는 <고급감>인자축이 평가축을 이루었다. 행위항목의 인자분석 결과는 주거공간의 경우, <작업행위>,<휴식행위>,<단란행위>의 3인자축이, 사무공간의 경우 <작업행위),<휴식행위>의 2인자축이 추출되어 주거공간의 경우, 활동성 평가가 높은 조명환경은 작업행위에 적합하며 반대로 활동성평가가 낮은 조명환경일수록 휴식행위에 적합한 것으로 나타났다 사무공간의 경우도 마찬가지로 작업행위에 가장 큰 영향을 미치는 분위기 인자는 활동성으로 나타나 활동성평가 높을수록 작업행위에 적합하며, 후식행위는 평가성 평가가 높은 조명환경에 적합한 것으로 나타났다.

• 발명특허
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• v.35 no.6
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• pp.26-33
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• 2010

본 연구에서는, 방명창의력 증진을 위한 전문 블록(다모블록)개발을 시도하고, 대학생들의 사용성 평가를 통해 통계적 검증이 이루어졌다. 개발된 다모블록은 각 면을 오목과 블록구조로 형성하여, 4면을 자유롭게 결합하는 슬라이드 방식의 특허기술이 적용된다. 결론적으로 개발된 다모블록은 발명교구로 사용될 수 있음은 물론, 발명원리를 발견하고 학생들의 다양한 발명사고 능력개발에 유용한 블록으로 평가된다.

• Journal of the Korean Institute of Landscape Architecture
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• v.13 no.1
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• pp.95-107
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• 1985

This study is purposed to investigate the role of grasses as the Green Foundation effect on the visual preference to flowering tree and shrub being the principal elements of natural landscape early in the spring. As the flowering shrub materials, Rhododendron mucronulatum and Forsythia Kreana were adopted. Total 48 slides were photographed at the 8 different lawn areas with the 6 planting combinations of flowering shrub materials, and 10 landscape variables - dimensional and color - were measured and preference scores were taken by slide evaluations. The results were : 1) The visual preference to the landscape of flowering shrub in the lawn area was changed with the different lawn situations. 2) With important 4 variables, multilinear regression model was established, hence Y =40.4 + 9.6($X_1$) -7.8($X_2$) -26.8($X_3$) + 15.2($X_4$) where, Y : estimated preference score $X_1$: perimeter of flower zone $X_2$: value of green covered zone $X_3$: hue of green covered zone $X_4$: chroma of green covered zone 3) Most effective variable was 'hue of green covered zone', hence the more green the lawn area ism the more preferred landscape or the more effective green foundation is.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1373-1374
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• 2011

• Journal of the Korean Society for Railway
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• v.20 no.2
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• pp.241-247
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• 2017

Railway bridges with continuously welded rail have a limitation of span length due to track-bridge interaction. In order to overcome this, a sliding slab track system has been developed that comprises with a low-frictional sliding layer between the bridge deck and the track slab to isolate the longitudinal behavior between the bridge and the track. In this study, a real scale track system is prepared to experimentally evaluate the longitudinal frictional behavior. Applied loading rates were 0.2, 1.0, 5.0 and 10mm/min; vertical mass on the track are track slab only, 5,000 and 10,000kg added mass, respectively. Test results showed that the resulting frictional coefficients varied from 0.22 to 0.33. In addition, 10,000 cycle loadings were applied to simulate repetitive sliding to represent 30 years of service life. The frictional coefficient increase was measured and found to be 7% of that of the initial loading stage, which means that the sliding layer is adequate to provide low-frictional behavior for the sliding slab track system. Effects of changes of the frictional coefficient of the sliding layer were analyzed by rail-structure interaction analysis.

• Tunnel and Underground Space
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• v.33 no.1
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• pp.42-56
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• 2023

In deep geological disposal of high-level radioactive waste (HLW), the natural barrier must physically support the disposal facility and delay the movement of radionuclides for at least hundreds of thousands of years. To evaluate the long-term geological evolution of the natural barriers, it is essential to analyze the long-term behavior of rock joints, including the frictional healing behavior. This study aimed to experimentally analyze the frictional healing behavior of rock joints under hydro-mechanical (H-M) conditions through the slide-hold-slide (SHS) test. The SHS tests were performed under mechanical and H-M conditions for joint specimens of different roughness. In the H-M conditions, the frictional healing rate tended to increase, which was more evident in the specimens with large roughness. In addition, it was confirmed that the effect of the hydro-mechanical conditions was more significant when the effective normal stress acting on the joint surface was small. These results are expected to be used as fundamental data to understand the frictional healing behavior of rock joints in the natural barriers.

• Tunnel and Underground Space
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• v.33 no.1
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• pp.10-28
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• 2023

Long-term shear behavior of the rock discontinuities should be analyzed and its stability should be evaluated to ensure the long-term stability of a high-level radioactive waste disposal repository. The long-term shear behavior of the discontinuities can be modeled with creep and RSF models. The shear creep test, velocity step test, and slide-hold-slide test can be performed to determine their model parameters or analyze the shear behavior by experiments under various conditions. Testing apparatuses for direct shear, triaxial compression, and biaxial shear were mainly used and improved to reproduce the thermo-hydro-mechanical conditions of local bedrock, and it was confirmed that the shear behavior could vary. In order to design a high-level radioactive waste disposal site in Korea, the long-term behavior of rock discontinuities should be investigated in consideration of rock types, thermo-hydro-mechanical conditions, metamorphism, and restoration of shear resistance.