• Journal of Korean Society of Steel Construction
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• v.27 no.2
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• pp.155-167
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• 2015

If of application of the deep deckting floor in long span more than 6m, the deflection caused by the construction load occurred high. Because the constructing-works and safety by this deflection, take actually supports to laborers working on the deck. However, installed supports are having difficultly such as the restricted passage, deficiency of working space, and lowering of efficiency. And toward-opening deck is seen as local buckling of web plate, flexural-torsional buckling, and gradually opening of corrugated decking. In this study, we will suggest a deep decking floor system that reinforced with both ends cap plates for toward-opneing decking change from opening to closing. The constructing deflection of a deep decking more than 6m must be satified 30mm and L/180 as proposed. Full-scale field tests loading by sand conducted a deep decking reinforced with and without cap plate. In conclusion, the specimen reinforced with cap plates have shown that to ensure the negative moment $wl^2/18$. And constructing-deflection of deep decking shown that to satisfy the evaluation value (L/180 or 30mm).

• Journal of the Korean GEO-environmental Society
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• v.15 no.9
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• pp.37-45
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• 2014

An embedded length of monopile caused by a scouring should be evaluated to monitor the stability of offshore foundations, because offshore foundations are affected by horizontal load. The objective of this study is to evaluate the scouring around offshore foundation by using electrical resistivity and to estimate ground stiffness by using shear wave tomography. The electrical resistivity profiles and shear wave tomography were measured according to the scour depth of model ground prepared with sand and cement. Several electrodes and bender elements were used to measure the electrical resistivity and shear waves, respectively. The electrode sets are attached on the monopile surface and bender elements are arranged in $7{\times}7$ arrays by using nylone frames. The electrical resistivity profiles and shear wave tomography are acquired by laboratory experiment. Maximum scour depth was estimated by electrical resistivity profiles and the ground stiffness of model ground was estimated by shear wave tomography. This study suggests that the electrical resistivity profiles and shear wave tomography may be useful for monitoring the stability of the offshore foundations.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.165-174
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• 2004

This study is about a horizontal load test of buoyance anchor installed in the section where underground water level happens in the depth of 5m under the ground when the ground is excavated, because the section as a excavation section of high speed railway ${\bigcirc}{\bigcirc}$ station is near a rivers and because the section always has a reservoir of full water level on the left. Therefore, in this study we will appraise the long-term stability of the structure permanently being taken buoyance by the underground water level, through the spot test of the buoyance anchor installed in the section where underground water level happens. For that, Bar Type anchor is used, which can get enough pulling-out force by a method to resist buoyance by using friction force against the ground by high strength steel rod or steel wire. Anti-buoyance anchor is installed on the bottom slab of underground structure being taken horizontal force by the braking and accelerating of high speed train. And, It is aimed to analyze and grasp the review result of stability for the horizontal force that happens at the parking and stopping of high speed train, by executing horizontal load test for the grasping of the movements characteristic of buoyance anchor.

• Korean Journal of Materials Research
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• v.10 no.2
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• pp.160-165
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• 2000

We have investigated the electrical and diffusion barrier properties of MgO produced on the surface of Cu (Mg) alloy. Also the diffusion barrier property of the interfacial MgO between Cu alloy and $SiO_2$ has been examined. The results show that the $150\;{\AA}$-MgO layer on the surface remains stable up to $700^{\circ}C$, preventing the interdiffusion of C Cu and Si in Si/MgO/Cu(Mg) structure. It also has the breakdown voltage of 4.5V and leakage current density of $10^{-7}A/\textrm{cm}^2/$. In addition, the combined structure of $Si_3N4(100{\AA})/MgO(100{\AA})$ increases the breakdown voltage up to lOV and reduces the leakage current density to $8{\tiems}10^{-7}A/\textrm{cm}^2$. Furthermore, the interfacial MgO formed by the chemical reac­t tion of Mg and $SiO_2$ reduces the diffusion of copper into $SiO_2$ substrate. Consequently, Cu(Mg) alloy can be applied as a g gate electrode in TFT /LCDs, reducing the process steps.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.331-339
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• 2020

In this study, ways to reduce the edge pressure at the bottom plate of the caisson breakwater were considered. The water depth, freeboard, design wave height and period, and the location of the center of gravity on the super-structure of the breakwater were selected as key design variables that influence the edge pressure, and analyzed how the edge pressure changes according to the change of this key variables. The pressure distribution formulae suggested in the design standard was applied for the calculation of design wave forces. Based on the wave forces, the required effective self-weight of the super-structure and the minimum width of the caisson were determined to have a safety factor of 1.2 against sliding and overturning. From the results, it was found that the edge pressure rapidly increased as the water depth increased, and could exceed the allowable bearing capacity when it reached a certain water depth which is 20 m within the analysis conditions. It was also confirmed that the edge pressure gradually increased linearly as the freeboard increased, but decreased with the increase of the wave height and period. This edge pressure could be significantly reduced up to more than 20% by moving the center of gravity of the super-structure to the seaside, which is 5% of the caisson width. Based on the analysis results and the recently conducted research results, a method was proposed to reduce the edge pressure that can be used in the design.

• Geophysics and Geophysical Exploration
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• v.17 no.4
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• pp.231-241
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• 2014

Recently, single channel seismic survey for engineering purpose have been used widely taking advantage of simple processing. However it is very difficult to obtain high fidelity subsurface image by single channel seismic due to insufficient fold coverage. Recently, seismic waveform inversion in multi channel seismic survey is utilized for accurate subsurface imaging even in complex terrains. In this paper, we propose the seismic waveform inversion algorithm for velocity model building using a single channel seismic data. We utilize the Gauss-Newton method and assume that subsurface model is 1-Dimensional. Seismic source estimation technique is used and offset effect is also corrected by removing delay time by offset. Proposed algorithm is verified by applying modified Marmousi2 model, and applied to field data set obtained in port of Busan.

• Convergence Security Journal
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• v.5 no.4
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• pp.41-48
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• 2005

Objective of this study is to design and implement security system based on intrusion tolerance technology for the improvement of dependability in defense system. In order to do so, I identify and extract core technologies through the research and analysis into characteristics, structures, main functions, and technologies of intrusion tolerance architecture. And I accomplish a design of security system through the redundant system based on these core technologies. To implement and verify intrusion tolerance system, I chose 'wargame system' as a subjected system, and accomplished 'Wargame Intrusion Tolerance System' and verified security required functions through a performance test. By applying showed security system into the development of application software based on intrusion tolerance, systematic and efficient system could be developed. Also applying 'WITDS' can solve the current security problems, and this will be basic model for design of security architecture in the federation system after.

• Korean Journal of Environment and Ecology
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• v.7 no.2
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• pp.118-134
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• 1994

This study was conducted to investigated the plant community structure and to revaluate the part of plant ecosystem on statement of environmental impact assessment in Muju resort golf course, Solch'on area, Tokyusan National Park. The actual vegetation was comprised of Pinus densiflora-Quercus mongolica-Q. serrata community(33.21%), Q. spp. community(27.30%), P. densiflora community(20.68%) and high mountain marsh(4.93%) etc., which communities were the major vegetation and the forest vegetation was came to being a peculiar to environmental condition. The degree of green naturality 8, 9 was covered 93% in survey area, and so this result reflect the stability of ecosystem. There was all the difference between the statement of environmental impact assessment of development concerned and this study result in the estimation of degree of green naturality. The plant community were divided into six groups in fifty-four plots by DCA and the dividing groups were P. densiflora, P. densiflora-Q. mongolica, P. densiflora-Q. serrata-F. mandschurica-B. davurica, Q. mongolica-Q. serrata-P. densiflora, Q. mongolica-Q. variabilis, Salix koreansis- B. davurica community. Except P. densiflora forest in survey site, the ecological succession trend of the other communities was seemed to be from P. densiflora to Q. spp.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.4
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• pp.9-17
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• 2013

This paper describes an experimental program to investigate the shear behavior of insulated concrete sandwich panels (CSPs) with different types of GFRP shear connector. The study included testing of 13 insulated CSP specimens with two types of surface conditions for extruded polystyrene (XPS) insulation and various shapes of shear connectors. All specimens were loaded in direct shear by means of push-out and were consist of three concrete panels, two insulation layer and four rows of GFRP shear connectors. Load-relative slip between concrete panel and insulation response of CSP specimens has been established through push-out shear test. Test results indicate that the surface condition of insulation has a significant effect on the bond strength between concrete panel and insulation. The specimen used XPS foam with 10mm deep slot shows higher bond strength than those used XPS foam with meshed surface. Corrugated GFRP shear connectors show equivalent strength to grid GFRP shear connectors. Cross-sectional area and embedded length of shear connector have a notable effect on overall response and inplane shear strength of the CSP specimens.

• Proceedings of the Korean Vacuum Society Conference
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• 2000.02a
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• pp.62-62
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• 2000

비접촉식 온도센서는 물체에서 방출하는 적외선 등의 복사신호를 열에너지로 전환하고 이를 다시 전기신호로 2차 에너지 변환하여 온도를 감지하는 센서로 인체 검지를 응용한 다양한 상품 및 교통, 방재, 빌딩 시스템 등의 분야에 널리 응용되고 있다. 비접촉식 적외선 센서는 열에너지를 전기에너지로 변환하는 방법에 따라 양자형과 열형으로 구분되며, 이중 양자형은 광전도나 광기전력 효과 등을 이용하여 감도 및 응답성이 우수하다는 장점을 지니고 있지만, 소자부를 80K 이하 온도로 유지시키는 냉각을 필요로 하므로 대형 제작이 불가피하고 그 용도가 제한적이다. 열형은 냉각이 필요 없고 소형으로 제작가능한 장점을 지니고 있어 써모 파일이나 초전체를 이용한 번용 센서가 보급되고 있다. 그러나 써모파일의 경우 출력되는 전기 신호가 미약하여 감도 및 응답성을 향상하기 위해 구조가 복잡하고, 특히 모터초퍼나 저항을 전압으로 변환시키는 전력기 등이 필요로 하는 단점을 지니고 있다. 따라서 이러한 문제점을 보완하기 위해 열전재료 박막을 이용한 적외선 센서를 개발하려는 노력이 진행중에 있다. 열전박막을 이용한 적외선 센서는 열전재료의 Seebeck 현상을 이용하여 열에너지에서 전기에너지의 변환이 자가발전으로 이루어져 offset과 외부 바이어스를 필요로 하지 않는다. 또한 작은 온도 변화에도 그 감도와 응답성이 높고, 출력신호가 커서 증폭기 등이 불필요한 장점을 지니고 있다. 특히 초전형 센서가 상온에서도 기판에 대한 열 확산을 제어해야 하는 문제점을 갖는 반면, 열전박막형 적외선 센서는 고온에서도 안정된 출력 신호를 얻을 수 있어 그 활용 온도 범위가 크게 확대될 것으로 기대된다. 본 실험에서는 우수한 열전특성을 갖는 (Bi1-xSbx)2Te3 박막을 얻기 위해 열팽창계수가 작고 알칼리 원소가 0.3% 이하로 포함되어 있는 corning glass(# 7059)를 기판으로 사용하였다. 또한 최적의 열전특성을 나타내는 조성을 실험적으로 구하기 위해 (Bi0.2Sbx)2Te3 조성의 합금 타？ 위에 Bi2Te3 및 Sb2Te3 chip을 올려놓고 그 면적을 변화시켜 다양한 조성의 열전박막을 증착하였다. 열전박막의 증착시 산화와 오염에 의한 열전특성 변화를 최소화하기 위해 초기진공도를 1$\times$10-6 Torr로 하였으며, Ar 가스를 흘려주어 2$\times$102 Torr 의 증착진공도를 유지하였다. 열전박막을 증착하기 전에 기판을 10분간 200W의 출력으로 RF 처리하였으며, 30$0^{\circ}C$에서 33 /sec의 속도로 (Bi1-xSbx)2Te3 박막을 증착하였다. 이와 같이 제조된 (Bi1-xSbx)2Te3 박막의 미세구조를 SEM으로 관찰하고 EDS로 조성을 분석하였으며, XRD를 이용하여 결정성을 관찰하였다. 또한 (Bi1-xSbx)2Te3 박막의 Seebeeck 계수 및 전기비저항을 측정하고 증착된 박막조성, 결정상, 미세구조와 열전특성간의 상관관계를 고찰하였다.