• 한국환경복원기술학회지
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• 제17권4호
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• pp.69-79
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• 2014

Coastal wetlands are among the most productive biomes in the Earth. The economic values include the direct use of a coastal wetland's ecosystem services, such as food, raw materials, recreation, and tourism. Other values comprise the indirect use of a coastal wetland's ecosystem services, such as carbon sequestration, waste-water treatment, and erosion prevention. In particular, Suncheon Bay is recently attracting attention as the most successful case of the preservation and restoration. This study applies Travel Cost Method (TCM) to estimate the economic value by drawing the demand curve for trips to Suncheon Bay. The TCM is an approach used for economic valuation of non-market goods and services. Based on the results of TCM, this study shows that the economic benefit from recreational uses of the site adds up to \174.7 billion per year. It is also significant in the sense that monetary information is suggested to help local policy makers evaluate the realistic values of coastal wetlands.

• 한국정밀공학회지
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• 제27권11호
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• pp.92-97
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• 2010

The object of this study is to investigate the definite method for pitting damaged surfaces. Pitting is a sort of fatigue damages and it is made by a repetitive load. For a judgment between damages or not, sensing vibrations of test equipment is simple. However, it is not only difficult to observe a growth of pitting but also impossible to detect the juncture of initial pitting. Therefore, a method for the pitting damaged area measuring technique was effectively implemented by Two Roller Machine. The change of surface damaged area was measured by an optical microscope in regular time and calculated by the use of dark and bright ratio of test specimens' pictures taken by optical microscope. In conclusion, S - N Curves gained by Failure rate - Cycle graph was led and the curves are able to be chosen as occasion demands for a failure area percentage.

• 한국분무공학회지
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• 제3권4호
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• pp.1-7
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• 1998

The measurement of breakup length of viscous liquid jet in stagnant air was conducted by a 3CCD digital video camera. The nozzle diameters of 4, 6, 8mm with L/d=50 were selected and the dynamic viscosity of viscous liquid made of glycerine and water was in the range of $1.061\times10^{-6}m^2/s$ to $4.935\times10^{-5}m^2/s$. The critical velocity is decreased and the breakup length is increased with the increase of nozzle diameter at the same dynamic viscosity of liquid. At the same nozzle diameter, the breakup length and the critical velocity are both increased with the increase of dynamic viscosity of liquid. It is found in the theoretical analysis that the initial disturbance level is the main cause of occurrance of critical Reynolds number in the stability curve. The comparison of experimental critical Reynolds number and the empirical correlation by Tanasawa and Toyota reveals the relatively good agreement.

• 무역학회지
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• 제44권1호
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• pp.17-30
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• 2019

This study is to investigate the effect of real exchange rate on bilateral trade balance between Korea and ASEAN 10 countries. Using quarterly data from 1991 to 2017 the paper analyzes whether or not the real depreciation of Korea's won could improve the trade balance in the short and long term. Based on Autoregressive Distributed Lag(ARDL) model, the empirical results show that trade balance, GDP, and real exchange rate are all cointegrated, representing the long-run relationship among variables. In the consideration of long-run relationship, the increases in ASEAN countries' GDP could have a negative impact and Korea's GDP positive impact on trade balance between Korea and ASEAN countries unexpectedly. For the main variable, the paper did not find the long-term effect of real exchange rate on the trade balance, for the short-term effect of the real exchange rate it was found that there exists the J-curve effect only in the case of Vietnam and Brunei. Therefore, these results imply that the intended policy concerning the exchange rate in the free-floating exchange rate system could be limited to improve the trade balance between Korea and ASEAN countries.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 춘계학술대회 논문집
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• pp.1807-1813
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• 2007

본 연구는 피난 시뮬레이션 프로그램 중 하나인 EXODUS를 사용하여 지하역사 피난모델분석에 그 목적이 있다. 이번 시뮬레이션에 사용된 모텔은 대구지하철(중앙로 역사) 이다. 시뮬레이션 조건으로는 사고당시의 상황을 참고하여, 지하3층 승강장에서부터 지하1층까지의 피난시간을 중점으로 하였으며, 승객수는 열차탑승인원 1079호 320명, 1080호 320명, 열차 외 승객360명 총1000명의 인원으로 시뮬레이션 하였고, 승객위치는 참고자료를 활용하였다. 화재시뮬레이션 부분은 CFAST 화제시뮬레이터를 이용하였다. 화재성장 시나리오로 $t^2$ 성장곡선 중 fast곡선을 선택하여 진행하였고, ZONE은 총 24개로 지 하3층 승강장 18개, 지하2층 6개로 나눴으며, 지하1층은 화재시뮬레이션에서 제외하였다. 화재 위치는 실제 화재발생 위치인 1079호 1호차로 하였으며 실제 사고타임테이블을 이용하여 가상 시나리오를 작성해 보았다. 총 시뮬레이션 시간은 1800s로 결정하였고, CFAST 결과값은 10초단위로 출력하였다. CFAST 결과값 중에서 ZONE별 상층부온도, 하층부온도, $CO^2$ 발생량을 사용하여 EXODUS시뮬레이터에 적용시켜 진행하였다. 진행결과 각 출구별방출률, 사망인원, 최종피난인원, 사망자 위치, 정체구간 등을 알 수 있었고, 이를 실제 대구지하철 사고와 비교 분석하여 보았다.

• BMB Reports
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• 제34권4호
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• pp.379-384
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• 2001

The cDNA encoding ribosomal protein was identified from a cDNA library of Schizosaccharomyces pombe. The nucleotide sequence of the 548 by cDNA clone reveals an open reading frame, which encodes a putative protein of 166 amino acids with a molecular mass of 18.3 kDa. The amino acid sequence of the S. pombe L11 protein is highly homologous with those of rat and fruit, while it is clearly less similar to those of prokaryotic counterparts. The 1,044 by upstream sequence, and the region encoding N-terminal 7 amino acids of the genomic DNA were fused into the promoterless $\beta$-galactosidase gene of the shuttle vector YEp357 in order to generate the fusion plasmid pHY L11. Synthesis of $\beta$-galactosidase from the fusion plasmid varied according to the growth curve. It decreased significantly in the growth-arrested yeast cells that were treated with aluminum chloride and mercuric chloride. However, it was enhanced by treatments with cadmium chloride ($2.5\;{\mu}M$), zinc chloride ($2.5\;{\mu}M$), and hydrogen peroxide (0.5 mM). This indicates that the expression of the L,11 gene could be induced by oxidative stress.

• 대한공간정보학회지
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• 제11권1호
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• pp.71-75
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• 2003

도로는 오랜 기간 동안 꾸준한 경제성장으로 경제적인 규모가 커짐에 따라 차량의 증가 및 대형화, 차량의 성능증대, 시간가치의 상승 및 교통의 고속화 등으로 교통상황이 크게 변화되었다. 최적 노선선정모델에 관한 연구는 컴퓨터와 지형공간정보의 발달로 인하여 1980년 후반부터 일부 연구가 이루어지고 있으며, 국내에서도 수치지형모델을 이용한 최적노선에 관한 연구를 비롯하여 토공량산정, 유토곡선출력, 자동화시스템구축등 많은 연구가 이루어지고 있다. 그리고 최근에는 컴퓨터의 발달로 VGIS(Virtual Geographic Information System)를 이용한 도로주행 시뮬레이션과 가상현실에 대한 연구가 이루어지고 있다. 본 연구는 노선설계에서 도로대안결정시 고려되는 주변시설 및 계발계획, 교통수요 예측등에 따른 검토 의견 외에 3차원시뮬레이션기법을 통한 경관분석과 환경영향분석요소의 추가가능성에 대하여 연구하였다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2011년도 학술발표회
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• pp.16-16
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• 2011

Statistics of extreme rainfall play a vital role in engineering practice from the perspective of mitigation and protection of infrastructure and human life from flooding. While flood frequency assessments, based on river flood flow data are preferred, the analysis of rainfall data is often more convenient due to the finer spatial nature of rainfall recording networks, often with longer records, and potentially more easily transferable from site to site. The rainfall frequency analysis as a design tool has developed over the years in New Zealand from Seelye's daily rainfall frequency maps in 1947 to Thompson's web based tool in 2010. This paper will present a history of the development of New Zealand rainfall frequency analysis methods, and the details of the latest method, so that comparisons may in future be made with the development of Korean methods. One of the main findings in the development of methods was new knowledge on the distribution of New Zealand rainfall extremes. The High Intensity Rainfall Design System (HIRDS.V3) method (Thompson, 2011) is based upon a regional rainfall frequency analysis with the following assumptions: $\bullet$ An "index flood" rainfall regional frequency method, using the median annual maximum rainfall as the indexing variable. $\bullet$ A regional dimensionless growth curve based on the Generalised Extreme Value (GEV), and using goodness of fit test for the GEV, Gumbel (EV1), and Generalised Logistic (GLO) distributions. $\bullet$ Mapping of median annual maximum rainfall and parameters of the regional growth curves, using thin-plate smoothing splines, a $2km\times2km$ grid, L moments statistics, 10 durations from 10 minutes to 72 hours, and a maximum Average Recurrence Interval of 100 years.

• 지역사회간호학회지
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• 제33권3호
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• pp.299-311
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• 2022

Purpose: Untreated depression in adolescents affects their entire life. It is important to detect and intervene early depression in adolescence considering the characteristics of adolescent's depressive symptoms accompanied by internalization and externalization. The aim of this study was to identify latent classes of depressive symptom trajectories of adolescents and determinants of classes in Korea. Methods: The three time-point (2018~2020) data derived from the Korean Children and Youth Panel Survey 2018 were used (N=2,325). Latent Growth Curve Modeling (LGCM) was conducted to explore the depressive symptom trajectories in all adolescents, and Latent Class Growth Modeling (LCGM) was conducted to identify each latent class. Multinomial logistic regression analysis was performed to confirm the determinants of each latent class. Results: The LGCM results showed that there was no statistically significant change in all adolescents' depressive symptoms for 3 years. However, the LCGM results showed that four latent classes showing different trajectories were distinguished: 1) Low-stable (intercept=14.39, non-significant slope), 2) moderate-increasing (intercept=19.62, significantly increasing slope), 3) high-stable (intercept=26.30, non-significant slope), and 4) high-rapidly decreasing (intercept=26.34, significantly rapidly decreasing slope). The multinomial logistic regression analysis showed that the significant determinants (i.e., gender, self-esteem, aggression, somatization, peer relationship) of each latent class were different. Conclusion: When screening adolescent's depression, it is necessary to monitor not only direct depression symptoms but also self-esteem, aggression, somatization symptoms, and peer relationships. The findings of this study may be valuable for nurses and policy makers to develop mental health programs for adolescents.

• 환경생물
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• 제26권2호
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• pp.57-65
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• 2008

진해만에서 분리한 중심목 규조류 S. costatum의 성장에 영향을 미치는 광량과 파장을 알기 위해 실내 실험을 수행하였다. 수온 20$^{\circ}C$와 염분 30 psu의 환경조건에서 광량과 성장의 관계식은 $\mu$=1.17 (I-5.25)/(I+81.8), (r=0.98)로 최대 성장속도는 1.17 day$^{-1}$, 반포화광량(K$_s$)은 92.4 ${\mu$mol photons $m^{-2}s^{-1}$ 그리고 보상광량(I$_0$)은 5.28 $\mu$mol photon $m^{-2}s^{-1}$)로 나타났다. 진해만에서 I$_0$에 해당하는 수심을 계산한 결과, 3월에서 5월은 3$\sim$5m, 6월은 11m, 7월에서 9월은 4m로 진해만에서 S. costatum은 표층에서 잘 성장할 것으로 나타났다. 하지만 광저해현상은 150 $\mu$mol photons $m^{-2}s^{-1}$ 이상의 광량에서 세포밀도의 감소를 보여, S. costatum의 성장을 위한 최적 수심은 상당히 제한되어 있을 것으로 사료된다. 성장에 미치는 파장의 영향을 알기 위해 발광 다이오드를 이용하여 근자외선 영역부터 근적외선영역을 포함하는 9개 파장 빛을 주사하였다. 25 $\mu$mol photons $m^{-2}s^{-1}$에서 S. costatum은 405, 470, 505, 525, 568, 644 nm에서 성장을 하였지만, 590m와 523nm에서는 성장하지 못하였다. 하지만 100 $\mu$mol photons $m^{-2}s^{-1}$는 모든 파장대에서 잘 성장하였다. 따라서 S. costatum은 황색파장대가 우점하는 폐쇄성 연안역에서 충분히 잘 성장할 수 있을 것으로 판단된다.