• Proceedings of the Korean Aquaculture Society Conference
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• 2004.05a
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• pp.83-84
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• 2004

• Journal of Power System Engineering
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• v.9 no.1
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• pp.50-56
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• 2005

The corrosion experiment was performed for 120 hours on the specimens in the natural seawater tank with four steps of the loaded torsional stress. The surface corrosion pattern of SCM440 area was showed global corrosion and narrow pitting, that was cause by galvanic corrosion between friction welded IN713LC and SCM440. But corrosion does not proceeded from IN713LC area. Initially, the average relative electrode potential and corrosion current were decreased suddenly, by and large, it was stabilized gradually tend to decreasing with the elapse of the immersion time. The corrosion rate was decreased by increasing the load stress, but 200 MPa specimen was showed most large value.

• Journal of Ocean Engineering and Technology
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• v.19 no.2 s.63
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• pp.53-59
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• 2005

The effect of pH on the corrosion characteristics in the dissimilar friction welded zone of IN713LC-SCM440 in the loaded torsional stress was studied. The corrosion experiment was performed for 120 hours on the specimens with five steps of pH. The surface corrosion pattern of the SCM440 area showed global corrosion and narrow pitting, which was caused by galvanic corrosion between friction welded IN713LC and SCM440, but corrosion did not proceeded from the IN713LC area. The average relative electrode potential gradually tends to decrease with the elapse of the immersion time in the acidity area. The average corrosion current also gradually tend to decrease The corrosion rate showed a larger value when the average relative electrode potential was higher and the average relative current was lower. The corrosion rate showed a larger value when the average relative electrode potential was higher in the acidity area, and it showed large when the average relative electrode potential was lower in the alkalinity area.

• Journal of Ocean Engineering and Technology
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• v.18 no.5
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• pp.50-56
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• 2004

This study is on the constant-current stress corrosion test, related to the load stress, in both the welded and non-welded zones of high tensile strength steel that is used for natural gas transmission. The surface corrosion pattern of the welded zone of API 5L-X65 specimens for natural gas transmission showed general corrosion and narrow pitting, and the pitting was increased with load stress. Initially, the average relative electrode potential and the average relative current of the high tensile strength steel, used for natural gas transmission specimens, were decreased rapidly, and the average relative electrode potential was higher and the average relative current was lower in welded zone, compared to base metal. The average relative electrode potential was decreased with load stress, and the average relative current was somewhat increased by increasing the load stress. The corrosion rate was less in welded zone, compared to base metal, and the corrosion rate was decreased by increasing the load stress.

• Journal of the Korean Magnetics Society
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• v.16 no.6
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• pp.305-308
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• 2006

Magnetic flux leakage (MFL) pigs are traditionally used for the detection of gross corrosion on steel pipelines used for the transmission of natural gas. Alternative nondestructive evaluation (NDE) modalities are required for the detection of stress corrosion cracking (SCC) which tends to exist in colonies oriented axially along the length of the pipeline. This paper describes the use of multiphase rotating magnetic fields in the remote region of the probe as a possible SCC detection mechanism. Details of a prototype pig and test rig are given and the challenges associated with the finite element modeling of the device are discussed. Initial experimental results show that this novel NDE modality is sensitive to axially oriented tight cracks.

• Journal of Sensor Science and Technology
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• v.30 no.3
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• pp.154-164
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• 2021

In this study, the IoT sensor technology required for improving the survival rate and high-density productivity of individual shrimp in smart shrimp farming (which involves the usage of recirculating aquaculture systems and biofloc technology) was analyzed. The principles and performances of domestic and overseas water quality monitoring IoT sensors were compared. Furthermore, the drawbacks of existing aquaculture monitoring technologies and the countermeasures for future aquaculture monitoring technologies were examined. In particular, for farming white-legged shrimp, an IoT sensor was employed to collect measurement indicators for managing the water quality environment in real-time, and the IoT sensor-based real-time monitoring technology was then analyzed for implementing the optimal farming environment. The results obtained from this study can potentially contribute to the realization of an autonomous farming platform that can improve the survival rate and productivity of shrimp, achieve feed reduction, improve the water quality environment, and save energy.

• The Journal of Bigdata
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• v.8 no.2
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• pp.73-82
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• 2023

With 78% of current fisheries workers being elderly, there's a pressing need to address labor shortages. Consequently, active research on smart aquaculture technologies, centered on object detection and tracking algorithms, is underway. These technologies allow for fish size analysis and behavior pattern forecasting, facilitating the development of real-time monitoring and automated systems. Our study utilized video data from cameras outside aquaculture facilities and implemented fish detection and tracking algorithms. We aimed to tackle high maintenance costs due to underwater conditions and camera corrosion from ammonia and pH levels. We evaluated the performance of a real-time system using YOLOv7 for fish detection and the SORT algorithm for movement tracking. YOLOv7 results demonstrated a trade-off between Recall and Precision, minimizing false detections from lighting, water currents, and shadows. Effective tracking was ascertained through re-identification. This research holds promise for enhancing smart aquaculture's operational efficiency and improving fishery facility management.

• Journal of Marine Life Science
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• v.7 no.2
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• pp.163-170
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• 2022

In this study, the results of hybridization were evaluated by analyzing the biomarkers of Haliotis discus hannai and hybrid abalone (H. madaka♀^*H. discus discus♂) in marine net cage. The survival rate was similar both experimental groups, but the growth (shell length) was about 10% faster in hybrid abalone. The deformity of respiratory pore in the hybrid abalone was about 6% lower than H. discus hannai, and the shell depression was about 15% lower in the hybrid abalone. In the biochemical composition, crude protein was about 3.1% higher in hybrid abalone, and showed similar values except for the crude protein. In the histological structure of the hepatopancreas, which performs the functions of digestion, absorption and detoxification of abalone, good results were obtained in the hybrid abalone. On these results, it is judged that the hybrid abalone will have high aquaculture productivity in the aquaculture environment.

• Proceedings of the KOR-BRONCHOESO Conference
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• 2003.09a
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• pp.111-111
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• 2003

부식제 섭취로 인한 가장 흔한 합병증은 인두-식도 협착이며, 이로 인한 구강섭취 장애는 심각한 문제를 초래한다 이의 치료에 있어 기존의 수술적 치료가 소개되었으나 만족스럽지 못한 결과를 가져왔다. 부식제 섭취로 인한 인두-식도 협착에 있어 본원에서 시행한 수술적 치료 결과에 대해 알아봄으로써 향후 인두-식도 협착 치료에 도움을 주고자 하였다. 2001년 12월부터 2003년 8월까지 본원 이비인후과와 일반외과에서 부식제 섭취로 인한 인후두 및 식도의 완전협착으로 진단 받고 치료를 시행 받은 4예를 대상으로 의무기록을 통하여 술전 이학적 소견, 수술적 치료방법, 술후 합병증, 구강 섭취 시기를 후향적으로 분석하였다. 모든 환자에서 술전 내시경 검사로 인두-식도 접합부에 협착소견을 확인하였으며, 이중 경구 식이가 전혀 가능하지 못하였던 3명의 환자는 전후두인두식도 절제술 및 대장대체술 시행 하였으며, Levine- tube로 관급식이가 가능하였던 1명의 환자는 내시경적 확장술만 시행 받았다. 전 후두인두식도 절제술 및 대장대체술을 시행받은 3명의 환자 모두에서 문합부 유루, 출혈은 없었으나, 그 중 1명에서 술후 재협착으로 내시경적 확장술을 시행 받았고 이 환자를 제외한 2명의 환자에서 술후 10일과 13일에 경구섭취가 가능하였고 재협착이 있었던 환자는 술후 43일에 경구섭취가 가능하였다. 대장대체술을 시행 받았던 환자에서는 연식 이상의 식사가 가능하였으나, 내시경적 확장술을 시행 받은 환자는 관급식이만 가능하였다. 부식제 섭취에 인한 인후두 및 식도 협착에 있어 대장을 이용한 대장 대체술식을 이용하여 인두-식도 협착 치료에 좋은 결과를 얻었으며, 대장대체술은 합병증 및 구강 섭취에 있어 좋은 결과를 가져다 주는 술식으로 판단되었다.결과를 이용하여 향후 전개될 홈 네트워크 서비스 및 관련시장의 발전 방향을 전망해 보고 이에 따른 기업이나 정부차원의 대응전략을 파악하고자 한다.육구에서는 큰 변화를 나타내고 있지 않았다(p<0.05). 운동과 비운동시킨 참돔의 지질 함량의 변화는 운동시킨 참돔은 운동으로 인한 에너지 소비로 인하여 함량이 유의적으로 감소했으며(r=-0.35), 비운동사육구에서는 절식으로 인하여 지질함량이 감소하였다(r=-0.38). 파괴강도와 가장 밀접한 영향을 가지는 콜라겐은 운동과 비운동 모두 사육기간동안 큰 변화는 보이지 않았다. 초기의 파괴강도값은 1.45±0.02kg(운동사육구), 1.36±0.18kg(비운동사육구)이였으며 사육기간동안 운동사육구는 파괴강도값이 증가한 반면, 비운동수조에서는 참돔의 파괴강도는 사육기간동안 큰 유의차가 없었다. 각 성분간의 상관도를 살펴보면, 수분함량과 파괴강도는 상관성을 가졌으며, 지질함량과 파괴강도도 같은 경향은 나타내었다. 운동기간동안의 파괴강도와 콜라겐 사이에는 상관성의 거의 없었다. 이는 운동기간에 따른 파괴강도의 증가가 콜라겐의 함량의 증가보다는 지질함량의 감소와 수분함량의 증가와 같은 성분과의 상관성이 크다고 판단된다. 다음으로는, 운동횟수에 의한 영향으로써 운동시간을 1일 6시간으로 설정하여, 운동횟수를 결정하기 위하여 오전, 오후에 각 3시간씩 운동시키는 방법과 오전부터 6시간동안 운동시키는 두 방법을 이용하여 품질을 비교하였다. 각 조건에 따라 운동시킨 참돔의 수분함량을 나타낸 것으로, 2회(오전 3시간, 오후 3시간)에 나누어서 운동시키기 위한 육의 수분함량은 73.37±2.02%를 나타냈으며, 1회(6시간 운동)운동시키기 위한 육은 71.74±1.66%을 나타내었다. 각각의 운동조건에서 양식된 참돔은

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.105-107
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• 2018

기존에 부유 해양구조물을 바다에서 고정시키기 위하여 수심의 2배 이상의 길이를 사용하는 잉여 계류로프는 해저바닥에서 유동하게 되어 해저 자연환경을 훼손하고, 해저바닥과 잦은 접촉으로 인해 마모로 손상되어 태풍 등 자연재해에서 부유구조물과 양식어장 등의 유실 등 잦은 피해 발생과 유동으로 부유물의 정확한 위치파악이 어려워 안전사고의 원인이 된다. 현재 계류로프로 사용되는 섬유로프와 쇠사슬(Chain)의 단점(전단 취약, 고중량, 부식, 내마모, 해양어패류 부착 등)을 개선하며, 수심의 길이만 연결 할 수 있어 정해진 위치를 이탈하지 않고 쇠사슬이 가지고 있는 장점(고인장력)을 지닌 계류로프에 대해 연구 하였다.