• 한국정밀공학회지
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• 제16권12호
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• pp.143-151
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• 1999

The shape of surface micro-crack is very irregular due to nonhomogeneous microstructure but is very important in respect to qualitative estimation of fatigue life. Fractal geomety can quantify the shape of surface mciro-crack. Fractal dimension is measured for surface micro-cracks with coast line and box counting method and estimates cycle ration in Al 2024-T3. The average fractal dimension $D_{favg}$ of surface micro-cracks has 3-parameter weibull distribution and location parameter is nearly constant but shape parameter decreases as cycle ration increases. The fractal dimension by coast line method is measured for individual surface micro-crack but the fractal dimension by box countin method is measured for all the surface micro-cracks under sampling area. Therefore, This paper shows fractal dimension $D_{fb}$ can predict cycle ratio $N/N_f$ more convenient than fractal dimension $D_{favg}$.

• 대한원격탐사학회지
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• 제31권1호
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• pp.29-38
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• 2015

The coastline influenced naturally and artificially changes dynamically. While the long-term change is influenced by the rise in the surface of the sea and the changes in water level of the rivers, the short-term change is influenced by the tide, earthquake and storm. Also, man-made thoughtless development such as construction of embankment and reclaimed land not considering erosion and deformation of coast has been causes for breaking functions of coast and damages on natural environment. In order to manage coastal environment and resources effectively, In this study is intended to analyze and predict erosion in coastal environment and changes in sedimentation quantitatively by detecting changes in coastal line from data collection for satellite images and aerial LiDAR data. The coastal line in 2007 and 2012 was extracted by manufacturing Digital Surface Model (DSM) with Aviation LiDAR materials. For the coastal line in 2009 and 2010, Normalized Difference Vegetation Index (NDVI) method was used to extract the KOMPSAT-2 image selected after considering tide level and wave height. The change rate of the coastal line is varied in line with the forms of the observation target but most of topography shows a tendency of being eroded as time goes by. Compared to the relatively monotonous beach of Taean, the gravel and rock has very complex form. Therefore, there are more errors in extraction of coastlines and the combination of transect and shoreline, which affect overall changes. Thus, we think the correction of the anomalies caused by these properties is required in the future research.

• Journal of Plant Biology
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• 제23권2호
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• pp.61-67
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• 1980

As a part of the environmental base line survey of the Onsan Industrial Base, Korea, marine algal communities were investigated using the quadrat method in Onsan-myon on the east coast of Korea from March to December of 1978. It was learned that the representative dominat species along the coast in the Onsan area throughout the year are Ulva pertusa, Pachymeniopsis elliptica, and Sargassum thunbergii. Both the number of algal species occurring in the quadrat (50$\times$50cm) and the total coverage were higher in March and September than in June and December. A total of 94 species (1 blue-green, 16 green, 25 brown, and 52 red algae) of marine algae was identified in this study.

• 해양환경안전학회지
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• 제24권2호
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• pp.171-178
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• 2018

해양경찰은 바다라는 극한 환경에서 임무수행 중 빈번히 사망 실종의 위험에 맞닥뜨린다. 사고 발생 시 신속한 신원확인을 위해 해양경찰연구센터는 해양경찰을 대상으로 DNA를 이용한 신원확인 시스템을 구축하였으며 사체가 발견되지 않을 경우를 대비해 국립묘지 안장이 가능한 장치 또한 마련하였다. 순직 실종 등 대비 신원확인용 인체유래물 보관사업 운영규칙에 따라 인체유래물의 관리, 보관, 폐기, 품질검사가 진행되며 이는 관리위원회의 감시 하에 행해진다. 한반도 해역에서는 매년 700여건의 해양 변사자가 발생하는데 사체가 늦게 발견되어 부패가 심하거나, 일부분만 발견되어 지문 또는 치아로 개인 식별이 불가능할 경우 해양 변사자의 신원확인을 위한 방법이 필요하다. 해양경찰연구센터가 운영중인 '인체유래물 보관사업'을 해양 수산 종사자, 관련 연구자, 해양 레저인에게까지 확대 실행한다면 해양 변사자 신원확인에 큰 도움이 될 것이다.

• 한국약용작물학회지
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• 제14권6호
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• pp.347-353
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• 2006

This study was conducted to evaluate the vegetation structure and ordination of the Peucedanum japonicum Thunb. community by the Phytosociological method, floristic composition table on east coast of South Korea. The vegetation of Peucedanum japonicum Thunb. community was classified into 2 communities such as the Aster Spathulifolius community and the calystegia soldanella-Artemisia princeps community. Vegetation of the Peucedanum japonicum Thunb. community with the Aster spathulifolius community was shown southward, whereas vegetation of Peucedanum japonicum Thunb. community with the calystegia soldanella-Artemisia princeps community was shown northward from the base line of Pohang at North latitude of 36" 05'. Accordingly, the Peucedanum japonicum Thunb. community was grown commonly with the Aster spathulifolius community southward of the base line of Pohang, whereas it was grown commonly with the calystegia soldanella-Artemisia princeps community northward on the east coast. All environmental conditions of habitat taken together, the optimum habitat of Peucedanum japonicum Thunb. was at Ulsan geographically and the middle region of sea cliff topography, and was suitable for alkali. sandyloam.

• Fisheries and Aquatic Sciences
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• 제18권4호
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• pp.411-416
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• 2015

We estimated abundance of the finless porpoise Neophocaena asiaeorientalis in the west coast of Korea in 2011 and compared it to the abundance data estimated by Park et al. (2007). The two researches used same line transect method operated by a vessel, and the study area were divided into the offshore and the inshore regions to assess variations in their abundance. In offshore regions population density of finless porpoises was $0.122ind./km^2$, which was lower than $0.565ind./km^2$ estimated in 2004. In inshore regions the population density was $0.151ind./km^2$, which was much lower than $0.638ind./km^2$ estimated in 2005. Thus, we estimate that the population densities of the finless porpoises in both the offshore and the inshore regions of the west coast of Korea has decreased by approximately 70% between 2004/2005 and 2011.

• 한국수산과학회지
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• 제16권4호
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• pp.368-378
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• 1983

본 연구는 1982년 6월부터 1983년 5월까지 전남 여수반도 남단에 위치한 오동도 해조군락의 특성을 밟히기 위하여 5개의 line transect를 설치하고 연간 계절별로 조사된 자료를 분석 하였다. 해조류의 수직분포는 상부군이 Gelidium divaricatum, Enteromorpha linza, Porphyra yezoensis, Scytosiphon lomentaria, Blidingia nana, Ectocarpus confervoides, 중부군이 Ulva pertusa, Chondria crassicaulis, 그리고 하부군은 Sargossum sagamianum, Undaria pinnatifida, Sargassum thunbergii 및 Gelidium amansii 등의 홍조류로 대표되었다. 출현해조의 종수와 피도는 4월에 최대이고 8월에 최소로되며 종별 우점도의 변화는 연중 출현종은 10월에, 일계절 출현종은 1월 또는 4월에 각각 최대치를 나타내었다. 유사도지수에 따른 5개 transect의 cluster analysis 결과 내만성군과 외양성의 2군으로 분류되었으며 본 지역은 남해안 중${\cdot}$동부 군락에 해당되는 Myelophycus simplex alliance의 Colpomenia sinuosa-Ecklonia cava association에 속한다고 본다.

• 전자공학회논문지
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• 제53권2호
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• pp.133-140
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• 2016

해안 수중 감시를 위하여 분산센서망를 해안에 설치하고, 이를 이용하여 표적을 탐지하고 표적의 위치를 추정하는 연구가 많이 이루어지고 있다. Zhou 등은 표적 탐지만 가능한 간단한 구조의 센서들로 구성된 분산센서망에서 표적을 탐지한 센서들의 위치 정보를 활용하여 표적의 위치를 추정하는 기법을 제안하였다. Zhou 등이 제안한 기법은 다른 기존의 기법에 비해 표적탐지 신호의 전파모델에 대한 파라미터들을 별도로 추정할 필요가 없고, 연산량이 적으며, 분산센서망에서 적은 량의 데이터만 송수신하여도 된다. 그러나 Zhou 기법은 표적의 위치 추정오차가 크다. Ryu는 추정오차를 줄이기 위하여 Zhou 기법을 수정하였다. 수정된 Zhou 기법은 Zhou 기법보다 추정성능이 향상되었지만, 여전히 비교적 큰 추정오차를 가지고 있다. 본 논문에서는 수정된 Zhou 기법으로 구한 표적의 방위각을 나타내는 직선과 표적을 탐지한 센서들과의 기하학적 구조를 고려한 표적위치 추정기법을 제안하였으며, 수정된 Zhou 기법에 기반을 두고 있다. 제안한 기법의 표적위치 추정성능이 Zhou 기법과 수정된 Zhou 기법 보다 향상되었음을 컴퓨터 시뮬레이션을 통하여 확인하였다.

• 한국농공학회지
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• 제45권3호
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• pp.103-115
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• 2003

This study examines groundwater movement system analysis and movement forecast algorithm using finite element method. The target is Cheongha-myeon area, Bukgu, Pohang-city which has many difficulties in water supply during drought period. From the comparison of the differences between obtained values by WINFlOW model and observed values, it is thought that groundwater head distribution under steady flow is reflected well at the level of reliability Groundwater movement of study area shows stable pattern from western watershed to eastern coastal area while flow path is dense and steep in the center of the coastal area. The results of particle tracing for each well show a comparatively straight line from the western boundary side to the observation position at the upper area of the well, and are analyzed as it diffuses according to getting closer to the coast at the lower area of the well. The result of effect circle examination attendant on pumping amount in study area shows variation tendency that groundwater head decreases at the side and the lower area more than at the upper area of the well when groundwater flows from west to east(coast). As mentioned above, satisfactory results of groundwater movement analysis using WINFlOW model, two dimensional groundwater movement analysis model, are obtained through the great decrease of physical uncertainty of groundwater movement system.

• 해양환경안전학회:학술대회논문집
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• 해양환경안전학회 2005년도 추계학술대회지
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• pp.65-69
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• 2005

해상용 RFID의 탐지 가능한 거리를 조사하기 위하여 프레넬 영역(fresnel zone)에서 가시선(Line Of Sight, LOS) 범위에 대한 이론적인 전파모드를 고찰하였다. 지구곡면에 대한 LOS의 구조적 모델을 제시하고, 전파 모드 이론과 특정 주파수에 대한 수평거리 계산 방법을 고찰하였다. 연구결과, 희망 탐지거리 확보를 위한 송수신기 안테나 높이와 기상환경에 의한 탐지거리의 영향 등에 대한 이론적 분석이 가능하였다.