• Proceedings of the KSRS Conference
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• 2006.03a
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• pp.79-82
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• 2006

조간대 지형의 발달과 변화에 대한 이해는 물순환 모델, 양식장 관리, 전자해도의 갱신, 연안개발 계획수립, 항로의 효율적 관리, 선박 안전항해, 상륙 작전 등에 있어서 매우 중요하다. 기존의 조간대 DEM 을 만드는 방법 중 위성영상을 이용한 waterline 방법과 선박을 이용한 음향측심(echo sounding) 방법이 있다. 이 연구의 목적은 위성 원격탐사 자료와 음향측심기 자료를 함께 사용하여 각각의 방법의 단점을 보완함으로서 조간대 DEM 의 정밀도를 향상시키는 것이다. 천수만 황도 조간대에 대해 음향측심에 의해 얻어진 자료를 관측소 조위와 단위를 일치시킨 후 광학위성으로부터 추출된 waterline 자료와 합성하여 DEM 을 제작하였다. 합성된 DEM 과 기존의 waterline 방법과 음향측심법으로 제작된 DEM 과 비교해 본 결과, 합성된 DEM 은 음향측심 자료에 의해 정밀도가 많이 향상되었으며 waterline 방법에 의해 지역적 특성이 잘 표현되었다. 따라서 개발된 방법은 음향측심 방법에 의해 만들어졌던 기존 해도의 정밀도를 업그레이드 하는데 활용될 수 있을 것으로 기대된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4B
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• pp.243-251
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• 2012

To investigate the characteristics of rip current occurring at Haeundae beach, observations obtained from a buoy and a CCTV were analyzed and numerical experiments were conducted. During observed rip-current events, the CCTV images showed that a couple of wave-trains, which are close to regular waves with slightly different directions, propagated to the beach, and wavelet analyses of data from the buoy showed very narrow-banded spectra with a peak frequency. From the evidences, it was inferred that a known mechanism of generating rip current due to the nodal line area of honeycomb-patterned wave crest was one of the significant factors of rip current occurrences of Haeundae beach. The mechanism has been explained by the following: When two wave-trains with slightly different directions propagate to a beach, wave crests of the incident wave-trains form honeycomb pattern due to nonlinear interaction. The nodal lines of honeycomb pattern are developed in the cross-shore direction. And longshore currents flow toward the nodal line area which has very low wave energy. Consequently their mass flux is expelled through the area toward the sea direction. To confirm the generation, numerical experiments were performed using a nonlinear Boussinesq equation model. In the cases with two incident wave-trains with slightly different directions and with a monochromatic wave propagating over a submerged shoal, it was seen that the honeycomb pattern of wave crests was well developed, and thus rip currents were evolved along the nodal lines.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.4 no.4
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• pp.261-270
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• 1992

To investigate the flow patterns and diffusions in the Taean coastal waters of the eastern Yellow Sea, hydraulic and numerical experiments of tidal currents and diffusions of dye and cooling water were performed during spring tide along with field observations. Flow patterns obtained by the hydraulic and numerical experiments approximately coincide with those of the field observations. In the fold observations of tidal current, currents flow southwestward during the ebb tide, while currents flow northeastward during the flood tide. and the maximum velocity is 2.13 ㎧ toward WSW direction. The Eulerian diffusion coefficient estimated from field measmements of current is 7.82$\times$10$^{5}$ $\textrm{cm}^2$/s. Diffusion coefficients obtained from the area of dye plume in the model are given by the expression 0.18 $r^{4}$3/, and the coefficients have the range of 10$^{5}$ ~10$^{6}$ $\textrm{cm}^2$/s. These values are similar to the Eulerian diffusion coefficient estimated fram field measurements. Diffusion coefficients obtained in the hydraulic model are one to two orders higher than those obtained in the Onsan Bay in the eastern waters and two to three orders higher than those obtained in the Chinhae Bay in the southern waters of the Korean Peninsula. Diffusion patterns of cooling water by numerical experiments are similar to those of dye plume by hydraulic experiments. Both hydraulic and numerical experiment results of diffusions of dye plume and cooling water in the Taean coastal waters, have shown that the diffusion during the ebb tide is more prevalent than one during the flood tide.

• Journal of Navigation and Port Research
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• v.27 no.4
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• pp.455-463
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• 2003

Time series of suspended sediment concentration, surface elevation and velocity were measured and analysed to investigate the role of waves and the predominance of infra-gravity wave component for sediment suspension phenomena in the surf zone. For the investigation in detail, we adopted the cross spectral analysis method between suspended sediment concentration and the characteristic values of wave, and ensemble average analysis method about long-period wave component, which is dominant to sediment suspension in the measurement point. The obtained results are summarized as follows: 1)The relationship between suspended sediment concentration and the characteristic values of wave is stronger for the long-period standing wave components(about 60s and 30s where the nodal point of the first mode and the anti-nodal point of the second mode are located at the measurement point, respectively) than the long wave components(about 100s), which have the most energetic power, 2) and also, it is cleared that suspended sediment concentration is increased in the case of the phase, the velocity components of the first mode long-period standing wave(60sec) were accelerated toward on-shore direction, that is, the water surface in offshore side is higher than on-shore side.

• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.1
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• pp.54-63
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• 2009

Various methods have been employed for acquiring beach surface data, which are used to monitor shoreline changes due to beach erosion. This study explores the possibility of constructing and implementing a surface model of beach using data acquired with a terrestrial laser scanner and RTK-GPS. Digital images and three-dimensional data of beach areas acquired at 20 cm intervals using a laser scanner were used to create a digital surface model covered with digital image. Seven months later, the beach area was surveyed using an RTK-GPS, and another beach model was constructed using the data collected with an accuracy of 1.9 cm. The use of a terrestrial laser scanner is expected to ensure acquisition of good quality results and help deal with seasonal changes in beach areas. Because readings obtained with the RTK-GPS are dependent on the number of sampling points in beach model, difficulties are encountered when fixing the survey points. However, RTK-GPS could be used to implement a three-dimensional model by correcting the hidden parts in images obtained using a terrestrial laser scanner. Therefore, an RTK-GPS and a terrestrial laser scanner can be used in combination to obtain more precise data for the construction of beach model data.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.274-279
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• 2003

위성영상을 이용한 새만금 지역의 DEM생성을 위하여 waterline method를 사용하였으며, 총 13개의 Landsat thematic mapper (TM) 위성영상 자료를 이용하여 1991년과 2000년 기준의 DEM을 생성하였다. 현장 수준측량 자료를 이용하여 생성된 DEM의 정밀도 검증을 실시하였으며, 2002년 3월에 100m 간격으로 측정된 실측자료를 이용하였다. 해안선 추출은 density slicing 방법을 사용하였으며, 사용된 밴드는 육지의 경계를 구분하는데 많이 쓰이는 밴드 4번, 5번 및 6번 밴드를 선택적으로 사용하였다. 절대고도 값의 대입을 위하여 waterline 추출에 사용된 위성영상의 획득 시간에 대해 해양조사원의 10분 간격 실측 조위를 사용하였으며, 추출된 13개 waterline의 최저 조위는 58cm 이고 최고 조위는 537cm 이다. 추출된 해안선에 수준측량 자료를 이용하여 검증한 결과 RMS 오차 9.91 cm, 표준편차 9.78 cm의 정밀도를 갖는 2000년도 DEM을 생성하였다. 새만금 지역의 waterline 추출 과정에서 만경강과 동진강 하구 지역은 강에 의한 에너지의 유입, 유출로 인한 변화가 심하여 두 지역을 DEM 생성에서 제외하였다. 이렇게 생성된 과거(19991년도) DEM과 현재(2000년도) DEM을 이용한 지형변화 비교는 두DEM 차이로 9년간의 새만금 조간대 변화를 계산하였다. 군산공항지역의 지형변화는 거의 없는 것으로 나타났으며, 새만금 방조제가 건설된 이후 개화도 주변지역의 변화가 가장 두드러진 지형적 변화로서 방조제 입ㆍ출구 지역은 빠른 유속에 의해서 과거에 비해 침식이 우세하며, 방조제에서 육지로 갈수록 퇴적이 우세한 것으로 관측되었다.보체계의 구축사업의 시각이 행정정보화, 생활정보화, 산업정보화 등 다양한 분야와 결합하여 보다 큰 시너지 효과와 사용자 중심의 서비스 개선을 창출할 수 있는 기반을 제공할 것을 기대해 본다.. 이상의 결과를 종합해볼 때, ${\beta}$-glucan은 고용량일 때 직접적으로 또는 $IFN-{\gamma}$ 존재시에는 저용량에서도 복강 큰 포식세로를 활성화시킬 뿐 아니라, 탐식효율도 높임으로써 면역기능을 증진 시키는 것으로 나타났고, 그 효과는 crude ${\beta}$-glucan의 추출조건에 따라 달라지는 것을 알 수 있었다.eveloped. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model,

• Korean Journal of Remote Sensing
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• v.16 no.3
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• pp.221-233
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• 2000

An intertidal topography is continuously changed due to morphodynamics processes. Detection and measurement of topographic change for a tidal flat is important to make an integrated coastal area management plan as well as to carry out sedimentologic study. The objective of this study is to generate intertidal DEM using leveling data and waterlines extracted from optical and microwave remotely sensed data in a relatively short period. Waterline is defined as the border line between exposed tidal flat and water body. The contour of the terrain height in tidal flat is equivalent to the waterline. One can utilize satellite images to generate intertidal DEM over large areas. Extraction of the waterline in a SAR image is a difficult task to perform partly because of the presence of speckle and partly because of similarity between the signal returned from the sea surface and that from the exposed tidal flat surface or land. Waterlines in SAR intensity and coherence map can effectively be extracted with MSP-RoA edge detector. From multiple images obtained over a range of tide elevation, it is possible to build up a set of heighted waterline within intertidal zone, and then a gridded DEM can be interpolated. We have tested the proposed method over the Gomso Bay, and succeeded in generating intertidal DEM with relatively high accuracy.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.281-290
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• 2016

Coastal areas, used as human utilization areas like leisure space, medical care, ports and power plants, etc., are regions that are continuously changing and interconnected with oceans and land. Regular monitoring of coastal changes is essential at key locations with such volatility. But the survey method of terrestial LiDAR(Light Detection and Ranging) system has much time consuming and many restrictions. For effective monitoring coastal changes, KIOST(Korea Institute of Ocean Science & Technology) has constructed a shipborne mobile LiDAR system. The shipborne mobile LiDAR system, installed in a research vessel, comprised a land based LiDAR(RIEGL LMS-420i), an IMU(MAGUS Inertial+), a RTKGNSS(LEICA GS15 GS25), and a fixed platform. The shipborne mobile LiDAR system is much more effective than a land based LiDAR system in the measuring of fore shore areas without shadow zone. Because the vessel with the shipborne mobile LiDAR system is continuously moved along the shoreline, it is possible to efficiently survey a large area in a relatively short time. We conducted test measurements in the Anmok-Songjung beach around the Gangneung port. Effective monitoring of the changes using the constructed shipborne mobile LiDAR system for seriously eroded coastal areas will be able to contribute to coastal erosion management and response.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.4
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• pp.211-217
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• 2001

Physical oceanographic environments in the coastal sea of Chung-Moon located in the south coast of Cheju Island, Korea, where water pollutions by growing tourism complex possibly start to influence on the ecological system, are studied with hydrographic data observed monthly during July 1997 to June 2000. Winter and summer characteristics are shown in December to April and June to October, respectively, and transitional characteristics are shown in May and November. Waters show 14{\sim}16^{\circ}C$ and 34${\sim}$34.7 psu in winter and $15{\sim}27^{\circ}C$ and 32${\sim}$34.3 psu in summer. It tells that Tsushima water distributes in the whole column in winter and in the lower layer in summer, and Yangtze coastal water appears in the surface water in summer. When the influence of Yangtze coastal water is strong, salinities below 30psu are shown. Stratification is formed in the depth of about 20 m from June to October, so that it is not shown in the near shore stations, of which the depth is about10 m. Isotherms and isohalines sometimes tend to be perpendicular to the coast line in the surface, which seems to show influences from the steam power plant near St. 1 and the sewage disposal plant near St. 3. During the observation period, temperatures in St. 1 are a little higher than those in St. 2 and St. 3 except for a couple of months in summer and salinities in St. 3 are mostly a little lower than those in St. 1 and St. 2. Their effects seem to be no more than $0.4^{\circ}C$ in a distance of 300 m and no more than 0.1 psu within a distance of 30 m.