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위성기반 Chl-a자료 공간보간 및 예측 방법 연구: 독도주변해역을 중심으로
전호군(Jeon, Ho-Kun),조홍연(Cho, Hong Yeon) 한국측량학회 2021 한국측량학회 학술대회자료집 Vol.2021 No.11
해색위성원격탐사기술은 상시 현장관측이 어려운 넓은 해양에 대해 지속적인 자료를 제공하는데 기여하고 있다. 그러나 해색위성은 해수표면과 위성사이에 위치한 구름에 의해 간섭을 많이 받으며 이로 인한 결측은 해양현상 모니터링에 부정적인 영향을 미친다. 이 연구에서는 국가해양위성센터에서 운영 중인 천리안1호(GOCI-1) 기반 Chl-a 생산물에 대해 보간과 예측하는 방법과 결과를 제시 및 비교한다.
항공 및 드론 영상을 이용한 테트라포드 연안활동장소에 대한 공극률 계산 기법에 관한 연구
전호군(Ho-Kun Jeon),박주한(Ju-Han Park),양찬수(Chan-Su Yang) 한국연안방재학회 2020 한국연안방재학회지 Vol.7 No.2
In 2016 and 2019, the death rate from fall accidents at breakwater and tetrapod was 14.2% and 16.3% of whole coastal activity accidents, a higher proportion than other types of accidents. But there is no quantitative basis for assessing the risk of fallen at tetrapod. Thus this study introduces the method of calculating the porosity of tetrapod by image processing. Aerial image of the National Geographic Information Institute (NGII) and drone image was used. The target area was the tetrapod of the breakwater near Korea Maritime and Ocean University, Yeongdo-gu, Busan City, South Korea. We compared porosity results from Otsu threshold and Adaptive threshold methods. The result shows that Adaptive method gives about 2 times difference between aerial and drone image while Otsu method shows 3 times difference. It is revealed that the adaptive method can be applied with porosity measurement for tetrapod.
단계적 임계치 결정을 통한 위성레이더이미지 내 선박 탐지
전호군(Ho-Kun Jeon),조홍연(Hong Yeon Cho) 한국항해항만학회 2023 한국항해항만학회 학술대회논문집 Vol.2023 No.1
선박자동식별장치(AIS)는 데이터의 활용편의성으로 인해 해상교통평가에 많이 사용되어 왔다. 그러나 AIS는 지형물에 의한 전파방해, 도달거리 한계로 인해 거리에 따라 선박위치가 누락되는 문제가 있다. 한편 위성레이더를 이용하면 이러한 문제로부터 자유롭게 광범위한해양영역에 분포한 선박위치를 파악할 수 있다. 이 연구에서는 합성개구레이더 Sentinel-1 이미지에 단계적으로 임계치를 결정하여 선박을 탐지하는 방법을 제시한다. 제시된 방법은 기존의 이동창 기반 임계치 결정방법에 비해 최대 25배 빠른 탐지 속도를 보였으며, AIS와의 매칭률에서는 유사한 결과를 보였다. AIS has been widely used for maritime traffic assessment for its convenience. However, AIS has problems with position missing due to radio interference and transmission distance limit. On the other hand, satellite radar determines the location of ships over a wide sea regardless of the problems. This study proposes a noble method of stepwise threshold determination to detect ships from Sentinel-1. The proposed method is up to 25 times faster than the existing moving window-based threshold determination method, and the detection accuracy is similar.
HMM을 이용한 어선 활동 예측 기법의 선박패스(V-Pass) 적용
박주한(Ju-Han Park),전호군(Ho-Kun Jeon),양찬수(Chan-Su Yang) 한국연안방재학회 2021 한국연안방재학회지 Vol.8 No.4
Illegal fishing has been a serious threat to the conservation of seafood resources and provoked the importance of marine surveillance. There are several types of fishing vessel monitoring systems operated by Republic of Korea, for example, Vessel Monitoring System(VMS), Automatic Identification System (AIS), V-Pass and VHF-DSC. However, those methods are not adaptable directly to fishing activity monitoring. The limitation requires more human resources to determine fishing status. Thus, this study proposes a method of estimating fishing activity from V-Pass, fishing vessel position reporting system, using Hidden Markov Model (HMM). HMM is a model to determine status through probability distribution for a sequence of time-series data. First of all, fishing activity status was labeled on V-Pass data. The distribution of speed on fishing activity was computed from the labeled data and HMM was constructed from the data obtained at Socheongcho Ocean Research Station (SORS). The model was first applied to the data of SORS for a test, and then Busan for validation. The model showed 99.4% and 89.6% as test and validation accuracy, respectively. It is concluded that the HMM can be applicable to predict a fishing activity from vessel tracks.
선속과 해양기상이 선박 연료소모량에 미치는 영향에 대한 실선 실험 해석
신대운(Dae-Woon Shin),양찬수(Chan-Su Yang),전호군(Ho-Kun Jeon) 한국연안방재학회 2021 한국연안방재학회지 Vol.8 No.2
Ship fuel consumption is affected by ship speed and ocean environmental factors, which are resistance to ships. There have been not only mainly theoretical studies due to the difficulty of obtaining real ship experiment data, but also insufficient studies on correlation analysis between ship speed and ocean environment factors. In this study, we performed data pre-processing work to interpolate and integrate multi-type and shape data acquired by real ship experiments. Using the integrated data, we analyzed an empirical correlation between FOC and ship speed, ocean environmental factors (wind, current, wave). Navigation experiments for collecting data were performed on five voyages, starting at Busan Port, Ulsan Port, and Ulleungdo Island. FOC data was extracted from the electronic flow meter pre-installed for the research on ship, and ship position (Lon, Lat), speed (SOG) data were acquired from AIS and mobile phone, and ocean environmental data was used grid-type data generated by Korea Operational Oceanographic System (KOOS). As a result of daily correlation analysis, SOG was the greatest influence on FOC. Current velocity had the greatest effect on FOC according to the stronger external force by correlation analysis of average filtering condition. When receiving external force from the ship s heading, Wind speed was derived the highest rate of change in FOC compared to the maximum correlation coefficient of daily analysis. Current velocity was analyzed to have a high effect on FOC at low ship speed (6~7kts), and wind velocity was analyzed to be correlated with FOC at high ship speed (10kts), and wave affected FOC at all ship speed. wind velocity was found to have the greatest influence on the FOC during Maneuvering, and the correlation of wave force was analyzed to be the highest correlation during Cruising. In addition, we found to save the FOC with increasing rate of SOG change to 11% according to a force of 65kg⋅f acting on ship stern. This study has a meaning in the aspect of using the results of the real ship experiment because the results were derived with the limited condition and ship type, it is necessary that supplementation research.