• 한국해안해양공학회지
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• 제16권3호
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• pp.171-177
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• 2004

디지털 영상을 이용한 새로운 파고계를 연구ㆍ개발하였으며 실험실의 조파 수조를 사용하여 검증하였다. 본 연구는 비디오 동영상이 1/15초의 일정한 간격으로 영상을 촬영하는 규칙성과 아날로그 영상에서 디지털 영상으로의 변환, 그리고 큰 용량의 저장 매체를 활용하였다. 본 파고계는 수면의 움직임에 따라 동일하게 움직이는 부이를 촬영한 영상에서 그 움직임을 자동으로 추출하는 방법으로 파고 관측을 하였으며 참값과 비교 검증하였다. 차후 개선 연구를 통하여 해안에 근접한 천해역에서 파랑 관측을 하는데 활용할 수 있을 것으로 보인다.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 1998년도 Proceedings of International Symposium on Remote Sensing
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• pp.89-94
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• 1998

Seasonal variation of attenuation coefficient spectra in Japan sea was extracted from underwater radiance/irradiance spectra observed by a moored buoy system developed by National Space Development Agency of Japan (NASDA). The buoy was deployed 9 months from August 31, 1996 to June 1, 1997. Throughout this period, it was collecting downward irradiance and upward radiance spectra under water at the depth of 1.5m and 6.5m everyday. The dairy averaged diffused attenuation coefficient spectra and underwater reflectance spectra were calculated. The results were compared with the absorption spectra of filtered samples obtained by validation cruises, which carried out 5 times during the moored period. Also, the natural fluorescence of chlorophyll a were extracted from the upward radiance spectra observed at 1.5m depth. The seasonal variation of the calculated attenuation coefficient spectra and the natural fluorescence were examined. The result shows a weak blooming of phytoplankton on November and a large blooming on April.

• 한국환경과학회지
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• 제15권5호
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• pp.417-430
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• 2006

We focused on improvement in simulation of wind fields for the complex coastal area. Local Analysis and Prediction System(LAPS) was used as a data assimilation method to improve initial conditions. Case studies of different LAPS inputs were performed to compare improvement of wind fields. Five cases have been employed : I) non data assimilation, II) all available data, III) AWS, buoy, QuikSCAT, IV) AWS, buoy, wind profiler, V) AWS, buoy, AMEDAS. Data assimilation can supplement insufficiency of the mesoscale model which does not represent detailed terrain effect and small scale atmospheric flow fields. Result assimilated all available data showed a good agreement to the observations rather than other cases and estimated veil the local meteorological characteristics including sea breeze and up-slope winds. Result using wind profiler data was the next best thing. This implies that data assimilation with many high-resolution sounding data could contribute to the improvements of good initial condition in the complex coastal area. As a result, these indicated that effective data assimilation process and application of the selective LAPS inputs played an important role in simulating wind fields accurately in a complex area.

• 한국지구과학회지
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• 제24권1호
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• pp.7-21
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• 2003

The state-of-art third generation wave prediction model WAM was applied to the Korean seas for a winter monsoon period of January 1997. The wind field used in the present study is the global NSCAT-ERS/NCEP blended winds, which was further interpolated using a bi-cubic spline interpolator to fine grid limited area shallow water regime surrounding the Korean seas. To evaluate and investigate the accuracy of WAM, the hindcasted wave heights are compared with observed data from two shallow water buoys off Chil-Bal and Duk-Juk. A detailed study has been carried with the various meteorological parameters in observed buoy data and its inter-dependency on model computed wave fields was also investigated. The RMS error between the observation and model computed wave heights results to 0.489 for Chil-Bal and 0.417 for Duk-Juk. A similar comparison between the observation and interpolated winds off Duk-Juk show RMS error of 2.28 which suggest a good estimate for wave modelling studies.

• International Journal of Naval Architecture and Ocean Engineering
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• 제5권4호
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• pp.513-528
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• 2013

A floating Oscillating Water Column (OWC) wave energy converter, a Backward Bent Duct Buoy (BBDB), was simulated using a state-of-the-art, two-dimensional, fully-nonlinear Numerical Wave Tank (NWT) technique. The hydrodynamic performance of the floating OWC device was evaluated in the time domain. The acceleration potential method, with a full-updated kernel matrix calculation associated with a mode decomposition scheme, was implemented to obtain accurate estimates of the hydrodynamic force and displacement of a freely floating BBDB. The developed NWT was based on the potential theory and the boundary element method with constant panels on the boundaries. The mixed Eulerian-Lagrangian (MEL) approach was employed to capture the nonlinear free surfaces inside the chamber that interacted with a pneumatic pressure, induced by the time-varying airflow velocity at the air duct. A special viscous damping was applied to the chamber free surface to represent the viscous energy loss due to the BBDB's shape and motions. The viscous damping coefficient was properly selected using a comparison of the experimental data. The calculated surface elevation, inside and outside the chamber, with a tuned viscous damping correlated reasonably well with the experimental data for various incident wave conditions. The conservation of the total wave energy in the computational domain was confirmed over the entire range of wave frequencies.

• 한국통신학회논문지
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• 제40권6호
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• pp.1200-1207
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• 2015

게이트웨이 부이시스템은 수중 어플리케이션 구현 시 수중-육상 간 네트워크 연계를 위한 시스템으로 수중노드와 육상국간 통신 연계, 수중 네트워크 모니터링 등을 수행한다. 본 논문에서는 다수의 수중노드로 수중 네트워크를 구현 시 취득된 데이터들을 육상국과 연계하여 실시간으로 모니터링이 가능한 게이트웨이 부이시스템 개발에 대해 소개한다. 개발된 게이트웨이 부이시스템은 수중음향통신모뎀, RF 통신시스템, 게이트웨이 운용시스템으로 구성되며, 게이트웨이 운용과 수중 네트워크 상태모니터링을 위한 육상국용 관제 프로그램을 구현하였다. 또한 실 해역 시험을 통해 실시간 수중 네트워크 모니터링, 게이트웨이 상태모니터링 등의 성능 검증을 수행하였다.

• 한국해양공학회지
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• 제23권1호
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• pp.89-95
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• 2009

The purpose of the present study was to evaluate the safety under extreme environmental conditions and the dynamic safety under service environment conditions, of oceanographic buoy mooring systems consisting of a variety of materials, including chain, wire rope, nylon rope, and polypropylene rope. For the static safety assessment of a mooring system, after the calculation of external forces and the division of a mooring system into finite elements, the numerical integral was conducted to yield the elemental static tension until satisfying the geometrical convergence condition. To evaluate the dynamic safety, various processes were considered, including data collection about the anticipated areas for mooring, a determination of the parameters for the interpretation, the interpretation of the dynamic characteristics based on an analytic equation that takes into account the heave motion effect of a buoy hull and a mooring system, and a fatigue analysis of the linear cumulative damage. Based on the analysis results, a supplementary proposal for a wire rope that has a fracture in an actual mooring area was established.

• 수산해양기술연구
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• 제51권4호
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• pp.600-613
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• 2015

The Fishing gear loss has been repeated every year in the West Sea; however, there has been no solution. So fisher men have undergone economic loss every year. Thus it is required to reduce the loss of fishing gear. In this study to find out the reason that the fishing gear is lost in the Sea, 10 years data of wave and current for 6 locations in the West Sea were investigated and a numerical modelling were conducted into the behaviour of a gillnet in wave and current. The fishing gear was modelled with the mass spring model. As a result, it came out into the open that the location where fishing gear loss occurred most frequently was Choongnam province. The height of the maximum significant wave in this province was 6.7 m and the period of that was 4.4 second. The maximum current speed was 0.7 m/s. As a result of simulation with these data, it was revealed that the buoy is one of the reasons to decrease the holding power of the gillnet. For example, the tension of anchor rope was decreased to 50% while the drag coefficient or volume of buoy was decreased to 25%. So it is predicted that an improvement of the buoy contributes to the reduction of the gillnet loss.

• 수산해양기술연구
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• 제58권2호
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• pp.153-158
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• 2022

A telesounder is a device that can monitor the appearance of fish in the sea on land and store fish detection data. This study was conducted to monitor the appearance of fish resources in coastal or near seas by using LTE communication for data transmission of the telesounder. The purpose of this study was to develop a prototype telesounder that can monitor the appearance of fish groups in the waters about 50 km away from the coast and store fish detection data. In this study, the prototype telesounder including a fish finder, communication device and battery for stable operation at sea was developed. The stability of telesounder buoy, data transmission/reception and expected use time were investigated. The expected use time of the telesounder using LTE communication with a lithium battery (12 V, 120 Ah) was about 274 hours under the conditions of 10 minutes off and 10 minutes on, about 520 hours under the conditions of 30 minutes off and 10 minutes on, and about 142 hours under continuous conditions. As a result of the sea test, it was found that the telesounder can be used in the sea area moved about 34 km from the land and the telesounder buoy was evaluated to have secured basic stability (buoyancy balance, waterproof, antenna strength, etc.) for operation in a marine environment.

• 대한원격탐사학회지
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• 제33권3호
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• pp.275-285
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• 2017

국가기상위성센터(NMSC)는 2011년 4월부터 천리안 위성(COMS) 해수면온도자료를 생산해왔다. 본 연구에서는 천리안 해수면온도 알고리즘을 이용하여 북서태평양 지역에 최적화된 해수면온도 산출 알고리즘 및 정지궤도와 극궤도 위성의 해수면온도 자료 합성 알고리즘을 개발하였다. 북서태평양 해역에 최적화된 천리안위성 해수면온도를 산출하기 위해 천리안 위성 자료와 부이(Buoy) 해수면온도 자료를 이용하여 해당지역에 최적화된 회귀계수를 산출 하였으며, 정확도 향상을 위한 새로운 구름 및 기타 오염 화소 제거와 부이자료의 품질검사 과정을 수행하였다. 그리고 본 연구에서 산출한 북서태평양 지역에 최적화된 천리안 위성 해수면 온도와 극궤도 위성(NOAA-18/19 and GCOM-W1) 해수면온도 자료를 이용하여 합성해수면 온도를 산출하였다. 합성 방법은 국립기상과학원에서 개발한 합성해수면온도 알고리즘을 응용하여 적용하였다(NIMR, 2009). 북서태평양 해역에 최적화된 천리안위성 해수면온도를 산출하기 위해 2011년 4월부터 2012년 3월까지의 위성 및 부이 자료를 사용하였고, 합성 해수면온도를 산출하기 위해 2012년 7월부터 2013년 6월까지의 자료를 사용하였다. 합성 해수면온도와 부이 해수면온도 자료를 비교한 결과 $0.95^{\circ}C$의 평균 제곱근 오차(RMSE)를 나타냈다.