• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.149-156
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• 2019

In the field of maintenance of power transmission lines, drones have been used for their patrol and inspection by KEPCO since 2017. This drone technology was originally developed by KEPCO Research Institute, and now workers from four regional offices of KEPCO have directly applied this technology to the drone patrol and inspection tasks. In the drone inspection system, a drone with an optical zooming camera and a thermal camera can fly automatically along the transmission lines by the ground control system developed by KEPCO Research Institute, but its camera gimbal has been remotely controlled by a field worker. Especially the drone patrol and inspection has been mainly applied for the transmission lines in the inaccessible areas such as regions with river-crossings, sea-crossings and mountains. There are often communication disruptions between the drone and its remote controller in such extreme fields of mountain areas with many barriers. This problem may cause the camera gimbal be out of control, even though the inspection drone flies along the flight path well. In addition, interference with the reception of real-time transmitted videos makes the field worker unable to operate it. To solve these problems, we have developed the auto-tracking camera gimbal system with deep learning method. The camera gimbal can track the transmission line automatically, even when the transmitted video on a remote controller is intermittently unavailable. To show the effectiveness of our camera gimbal system, its field test results will be presented in this paper.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.480-480
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• 2018

전 세계적으로 자연 친화, 하천생태계 보전, 친수하천 등을 조성하기 위한 대대적인 하천 정비사업이 활발히 진행 중에 있다. 최근 홍수로 인한 제방 붕괴에 대응하기 위한 제방의 안정화 및 개선을 위한 방법으로 기존의 시멘트와 같은 혼합물질을 사용하지 않고 환경 친화적이고 지속 가능한 대안에 대한 수요가 증가되고 있는 추세이며 현재 노후화 된 불안정 제방에 대한 보강대책을 수립해나가는 과정으로써 친환경 신소재를 활용하여 제방을 보호하는 연구가 수행되고 있다. 제방사면에 적용되는 신소재는 바이오폴리머를 활용한 재료로써 공동연구기관 카이스트에서 개발된 환경 친화적인 물질로 미생물에 의해 유도된 고인장 및 인체 무해성 등의 특성을 갖고 있으며 경제적 타당성인 측면에서 시멘트와 비교 분석 되어야 하고 실제 현장에서의 적용 가능성, 신뢰성 및 내구성 검토 등 성능을 보장하기 위한 지속적인 연구가 필요한 상황이다. 이에 본 안동하천실험센터에서는 중규모 제방을 직접 제작하여 수리모형실험을 통한 친환경 신소재 활용 제방의 안정성 및 성능 평가를 실시하였다. 수리실험 조건은 카이스트에서 제시된 레시피를 기반으로 먼저 분말형태의 바이이폴리머를 물과 희석하여 만들어진 바이오폴리머 용액을 흙과 혼합한 뒤 제방표면에 직접 미장작업을 수행하여 실험조건에 따라 일정한 두께(1cm, 3cm, 5cm)로 피복하였다. 이후 월류 붕괴 실험이 가능한 3 - 5일 정도의 양생기간을 거쳐 실험을 진행하였다. 실험결과는 다수의 고프로(GoPro) 및 비디오 카메라 등 다양한 영상장치를 이용하여 픽셀기반의 영상분석기법을 활용한 시간 흐름에 따른 제방 사면에서의 붕괴규모를 산정하여 신소재의 피복 두께에 따른 제체의 붕괴 거동 및 안정성을 평가하였으며, 또한 제방 파괴부에서의 흐름 상황 및 유속이 붕괴 발달에 미치는 영향을 분석하기 위하여 PIV 분석을 실시하였다. 이번 연구의 최종목표는 지속적인 예비실험을 수행하여 월류 및 침투, 파이핑 등 파괴 인자 별 신소재의 성능 개선 및 개발된 새로운 공법에 대한 효과 검토를 통한 최적안을 도출함으로써 향후 실규모 실험실증을 통한 신소재 시공 및 공법에 대한 현장적용 가능성 검증을 거쳐 최종적으로 신소재 제방 공법 설계 기술, 신소재 및 공법 표준안, 제방공법 안정성 평가 가이드라인 등을 제시하고자 하며, 이러한 실험데이터를 축적함으로써 실제 제방 붕괴 시 비상대처계획 수립에 필요한 기초자료로 활용이 가능할 것으로 사료된다.

• Asian Journal of Turfgrass Science
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• v.12 no.2
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• pp.113-126
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• 1998

Wear simulator로 답압이 가해진 크리핑 벤트그라스 (Agrostis palustris Huds.) 훼어웨이에서 관수방법·예지물 순환 및 질소시비수준의 여러 가지 잔디관리 요인이 엽조직 및 토양질소 함유량에 미치는 효과를 알아보기 위해 본 연구를 수행하였다. 연구포장은 'Penncross'크리핑 벤트그라스 반디밭으로 1988년에 sharpsburg silty-clay loam (Typic Argiudoll) 토양에 조성하였으며, 실험은 1989년부터 1991년까지 3년간 수행하였다. Split-split-plot 실험디자인을 사용하여 주구에 daily or biweekly irrigation, 세구에 clipping return or removal, 세세구에 low-N (5g), moderate-N (15g), high-N (25g N m-2 yr-1)처리를 난괴법 3 반복으로 배치하였다. 생육기간중 잔디예초는 12mm 예고로 일주일에 4번 실시하였고, 기타 잔디관리는 high maintenance 수준으로 유지되는 한지형 양잔디 훼어웨이 기준으로 실시하였다. 엽조직 및 토양샘플은 1989년 2회, 1990년과 1991년에는 3회씩 채취하여, 네브라스카 주립대 토양식물분석실에서 분석하였다. 답압이 가해진 크리핑 벤트그라스 훼어웨이 잔디에서 엽조직 질소함유량은 여러 가지 잔디관리 방법간 상호작용 효과가 관찰되었다. 1989년 나타난 질소시비수준과 관수방법간의 상호작용에서 daily irrigation 지역의 엽질소 함유량은 질소시비량이 low-N 수준에서 high-N 수준으로 증가함에 따라 3.51%에서 3.94%로 quadratic pattern으로 증가하였다. High-N 처리지역에서 엽질소 함유량은 daily irrigation 관수방법이 biweekly irrigation 관수방법보다 약 4% 정도 더 많은 것으로 나타났다. 엽질소 함유량은 특히 질소시비 수준에 따라 크게 영향을 받는 것으로 나타났다. 1990년 질소시비량이 low-N 수준에서 high-N 수준으로 증가함에 따라 3.50%에서 4.25%로 quadratic pattern으로 증가하였고, 1991년에는 4.20%에서 4.60%까지 linear pattern으로 증가하였다. High-N 처리구의 엽조직 질소함유량은 low-N 처리구와 비교시 1990년에는 21%, 1991년에는 10% 더 많은 것으로 나타났다. 잔디조성후 시간이 경과함에 따라 엽조직의 질소함유량도 증가하였다. Low-N 수준에서 1991년 엽질소 함유량은 1990년에 비해 20% 증가하였으며, high-N 수준에서는 1991년의 엽조직 질소함유량이 1990년 보다 8% 증가한 것으로 나타났다. 따라서, 잔디조성후 경과기간에 따라 연간 시비량을 조절할 필요가 있으며, 특히 새로 조성된 잔디밭과 조성된 지 어느 정도 지난 기존 잔디밭간에 차별화된 관리프로그램이 필요한 것으로 판단되었다. 잔디관리에서 답압이 가중되는 정도에 따라 지역별로 장기간 차별화된 관리 접근을 해야하고, 정기적으로 토양 및 엽분석을 실시해서 시비프로그램에 활용하는 것이 필요하다 하겠다. 본 연구결과 나타난 잔디관리 요인간 상호작용효과는 잔디관리시 여러 가지 관리방법에 따른 효과를 입체적으로 분석해서 해당 골프장 현실에 적합한 통합적인 잔디관리(integrated turfgrass management)의 필요성을 제시한다고 할 수 있겠으며, 또한 답압가중 정도에 따른 잔디관리요인간의 반응효과차이는 향후 무답압 지역에서 실시된 연구결과를 답압을 받고 있는 경기장 및 골프장 등의 잔디밭에 적용할 경우에는 주의깊게 데이터 활용을 해야 되리라고 사료되었다.

• Proceedings of the KSR Conference
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• 2008.11b
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• pp.993-999
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• 2008

A girder height limitation is the critical parameter for rapid construction of bridge deck and construction space limitation especially in urban area such as high population area and high density habitats. A standard post-tensioned I-shaped concrete girder usually demands relatively higher girder height in order to retain sufficient moment arm between compression force and tensile force. To elaborate this issue, a small U-shaped section with wide flanges can be used as a possible replacement of I-shaped standard girder. This prestressed concrete box girder allows more flexible girder height adjustment rather than standard I-shaped post-tensioned girder plus additional torsion resistance benefits of closed section. A 30m-long, 1.7m-high and 3.63m-wide actual small prestressed concrete box girder is designed and a laboratory test for its static behaviors by applying 6,200kN amount of load in the form of 4-point bending test was performed. The load-deflection curve and crack patterns at different loading stage are recorded. In addition, to extracting the dynamic characteristics such as natural frequency and damping ratio of this girder, several excitation tests with artificial mechanical exciter with un-symmetric mass are carried out using operational frequency sweep-up. Nonlinear finite element analysis of this 4 point bending test under monotonic static load is investigated and discussed with aids of concrete damaged plasticity formulation using ABAQUS program.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.42 no.2
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• pp.163-171
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• 2016

Steroid hormone, glucocorticoid (GC) has strong anti-inflammatory effects by binding to glucocorticoid receptor (GR) inhibiting the expression of inflammatory genes. Therefore, agents that activate the GR have been used for the treatment of dermatitis. However, the agents have side effects such as skin barrier dysfunction and dermal atrophy, inducing skin damage as well as skin aging. It has been reported that GC is activated by 11 beta-hydroxysteroid dehydrogenase type 1 ($11{\beta}$-HSD1) to increase the activity of the GR. This study aimed to identify natural materials that can effectively inhibit dexamethasone. We found that alpinetin isolated from Alpinia katsumadai extract has a significant effect on this. Alpinetin not only inhibited $11{\beta}$-HSD1 expression, but also suppressed the increase of phosphorylated GR and cortisol concentration. Alpinetin also recovered collagen expression in dexamethasone-treated dermal fibroblasts, and the reduction of dermal thickness in dexamethasnone-treated 3D skin model. These results suggest that alpinetin prevents skin aging induced by the increase of $11{\beta}$-HSD1 expression.

• Journal of the Korean Magnetics Society
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• v.8 no.6
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• pp.380-387
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• 1998

In this paper, a sensor material with Fe/Zr multilayer thin film, in which the change in the magnetization and strain with hydrogenation is maximized, were developed. Compositionally modulated (CM) Fe/Zr multilayers with a $Fe_{80}Zr_{20}$ composition and modulation wavelengths ($\lambda$) $3~50{\AA}$ were deposited by sequentially sputtering (RF diode) elemental Fe and Zr targets. The films were electrolytically hydrogenated to select the optimum Fe/Zr multilayers that show the maximum increases in the magnetization and strain with hydrogenation. The changes in the magnetic properties of the thin films after hydrogenation, were measured using a hysteresis graph and a vibrating sample magnetometer (VSM), and the strains induced in the films by hydrogenation were also measured using a laser heterodyne interferometer (LHI). The optimum sensor material selected was incorporated in a fiber-optic hydrogen sensor (that can sense indirectly amount of hydrogen injected) by depositing it directly on the sensing arm of a single-mode fiber Michelson interferometer. The developed sensor holds significant promise for non-destructive test evaluation (NDE) applications because it is expected to be useful for detecting easily and accurately the subsurface corrosion in structural systems.

• Korean Journal of Optics and Photonics
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• v.14 no.3
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• pp.343-348
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• 2003

Indium tin oxide (ITO) thin films (170 nm) were grown by DC magnetron sputtering deposition on Coming glass substrates without a post annealing. The electrical transport and optical properties of the films have been investigated as a function of deposition temperature $T_{s}$ (10$0^{\circ}C$$\leq$ $T_{s}$$\leq$35$0^{\circ}C$) and oxygen partial pressure $P_{o_{2}}$, (0 $P_{o_{2}}$ $\leq$ 10$^{-5}$ torr). Films were deposited from a high density (99% of theoretical density) ITO target (I $n_2$ $O_3$: Sn $O_2$= 90 wt% : 10 wt%) made of ITO nano powders. With an increase of $T_{s}$ the electrical resistivity p of ITO thin films was found to decrease, but the mobility $\mu$$_{H}$ was found to increase. The carrier density nu shows the maximum value of 6.6$\times$10$^{20}$ /㎤ at $T_{s}$ = 30$0^{\circ}C$. At fixed Is, with an increase of the oxygen partial pressure, $n_{H}$ and $\mu$$_{H}$ were found to decrease, but p was found to increase. The minimum resistivity and maximum mobility values of the ITO films were found to be 0.3 mΩ.cm and 39.3 $\textrm{cm}^2$/V.s, respectively. The visible transmittance of the ITO films was above 80%.. 80%..

• Korea journal of population studies
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• v.11 no.1
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• pp.197-203
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• 1988

In order to examine cause-specific mortality in Korea by comparing mortality of Japan, various mortality indicators are calculated using 1995 of ficial statistics of twonations. The mortality measures are cause-specific mortality rate by sex, age, andmarital status, cause-specific age-standardized death rate and potential years of lifelost, and their ratios by sex and nation. Items of major causes of death include allcauses (total deaths),tuberculosis, malignant neoplasm, diabetes mellitushypertensive diseases, heart diseases, cerebrovascular diseases, liver diseasestransport accidents, and suicide. Major characteristics of mortality in Korea are asfollows . (1) Death rates from most causes except suicide are higher in Korea thanJapan and especially death rates from tuberculosis, hypertensive diseases, liverdiseases, and transport accidents are higher for economically active Koreans : (2)Death rates from tuberculosis, liver diseases, transport accidents, and malignantneoplasm are salient for Korean children (3) Sex-differentials in mortality fromliver diseases, tuberculosis , and transport accidents are large for economically activeKoreans, because male mortality is higher than female mortality : (4) Suicide ratesare lower for economically active males, and higher for females aged 10s and 20s inKorea than Japan : (5) Death rates are highest f3r divorced or widowed under 45years of age depending on causes, but death rates from all causes are highest fornever-married of the age 45 and over in Korea : and (6) Sex-differentials inmortality are greatest for widowed in Korea and for divorced in Japan.

• Food Science and Preservation
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• v.18 no.6
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• pp.961-966
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• 2011

This research was carried out to evaluate the value of tofu containing mushroom as a immunomodulator. Tofu was made using $CaSO_4{\cdot}2H_2O$ or Lactobacillus extract as a coagulant after adding powder of fruit bodies or mycelia of Letino edodes and Lepista nuda to soybean milk. Proximate compositions of tofu and tofu containing mushroom were analyzed. Levels of interferon ${\gamma}$ (IFN-${\gamma}$), interleukin 4 (IL-4) and tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) in culture media of lymphocytes collected from mouse spleens after being injected with mushroom, regular tofu, or tofu made with mushroom were measured by sandwich ELISA. In addition, concentrations of IgG1, IgG2a and IgE in plasma or lymphocyte culture media were analyzed. Crude protein, crude lipid and crude ash were decreased in tofu containing mushroom but phosphorus was increased significantly. IFN-${\gamma}$ concentration was significantly decreased in mice injected with fruit body or tofu alone. IL-4 level was decreased significantly in mice injected with tofu containing fruit body of L. edodes. However, TNF-${\alpha}$ was increased in mice injected with tofu containing fruit body of L. edodes. Plasma levels of IgG1 were increased in almost all groups, while there was no significant change in IgG2a levels among treated mice groups. Concentrations of IgG1 and IgG2a were increased significantly in lymphocyte culture media of mice injected with tofu containing mushroom. Plasma levels of IgE level was significantly increased in mice injected with tofu or fruit body of L. edodes, but not in mice treated with tofu containing mushroom. These results showed that tofu with mushroom affected immune activities, and it seems valuable to consider developing the mixture of tofu and L. edodes as an immunomodulator.

• Korean Journal of Plant Resources
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• v.23 no.2
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• pp.123-130
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• 2010

Present studies were conducted to investigate the effects of autoclaving on antioxidant activities of Achillea alpina and Solodago virgurea. At early April, young leaves of 2 species were collected, subjected to autoclaving ($121^{\circ}C$, 1.2 atmospheric pressure, 15 minutes), freezed-dried, grinded, and extracted with 80% ethanol. The same process was repeated with unautoclaved control. Total polyphenol and flavonoid contents, scavenging activities on DPPH and ABTS radicals and ferrous ion chelating effects were analyzed. Extraction yield of autoclaved S. virgurea was 39.55% and A. alpina 28.15%. In both species, autoclaving significantly reduced scavenging activities on DPPH and ABTS radicals. On the contrary, ferrous ion chelating effects increased after autoclaving, especially in young leaves of A. alpina. Autoclaving resulted in decrease of polyphenol and flavonoid contents, especially in the A. alpina. The present experiments demonstrated that autoclaving had negative effects on antioxidant activities of A. alpina and S. virgurea, except in ferrous ion chelating effects. Young leaves of former species were unstable to heat treatment, resulting in big lose of antioxidant activity.