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울릉도 해역의 실시간 수중 영상 데이터를 활용한 AI기반 어류 자동 탐지 및 분류 시스템 개발
No full text울릉도 해역은 국내에서 가장 높은 투명도를 보이며, 한류와 난류가 교차하는 영향으로 다양한 해양생물이 서식하여 주변 해역의 보전 및 학술적 가치가 높은 바다이다. 이에 2024년 5월 울릉도 북쪽 수심 6m에 수중카메라를 설치하여 8월 6일까지 24시간 연속 촬영 및 녹화를 하였고, 녹화 영상은 60분에 1개의 파일을 생성하여 총 2,278개, 136,680분의 영상이 기록되었다.
이를 활용하여 해당 기간 영상에 출현이 확인된 18종의 어류 중 영상에서 세밀한 분류가 어려운 망상어, 인상어, 방어, 부시리 등은 과 또는 속으로 구분하여 15종의 어종별 분류를 위한 데이터셋을 구축하고 있으며 기록된 영상의 출현 어종이 시간대별로 달라질 수 있다는 점을 감안하여 하루 24개의 영상을 기준으로 8시, 12시, 17시 및 야간 1개의 총 4개 영상을 분당 1장씩 캡쳐한 후 그 안에 분류가 가능한 모든 어종을 Roboflow를 이용, 개별 프레임 내 어류의 식별 및 라벨링 작업을 수행하고 있다. Roboflow는 이미지 및 영상 데이터를 AI모델 학습에 적합한 형태로 전처리하고, 효율적인 라벨링 및 증강 기능을 제공하는 플랫폼으로 본 연구에서는 이를 활용하여 높은 품질의 데이터셋 구축과 정확도 높은 어류 탐지 및 분류 모델을 개발하고자 한다.2
Characteristics Analysis of Extreme Wave Height Distribution Using Wave Observation Data around the Korean Marginal Seas
No full textWave data is one of the critical design variables in the planning and design of offshore structures. With the adoption of reliability-based probabilistic design approaches, quantifying the uncertainty associated with design variables has become a fundamental requirement. Offshore structures are generally designed to withstand wave heights corresponding to return periods of 50 or 100 years, for which extreme analysis is employed to estimate the design wave height. The primary objective of extreme analysis is to define the relationship between the magnitude and frequency of extreme wave using probability distributions. Data availability is a crucial factor in this process. In Korea, previous studies relied on hindcast data for estimating extreme wave heights. However, with the recent accumulation of long-term measured wave data along the Korean coast, it is now possible to more accurately characterize site-specific wave conditions. In this study, extreme value analysis was performed using long-term observational wave data collected from multiple coastal locations. Four candidate probability distributions—Gumbel, Generalized Extreme Value (GEV), Weibull-3, and Generalized Hyperbolic—were examined. Parameters for each distribution were estimated using the Maximum Likelihood Estimation (MLE) method, and their performance was evaluated through goodness-of-fit tests. The most suitable probability density function was selected based on these assessments, and the characteristics of each distribution were analyzed in detail. As a result, it was found that the choice of distribution model significantly influences the estimated design wave height, particularly in the tail region, where extreme events are extrapolated. Depending on the selected distribution, design wave heights may be either overestimated or underestimated. These findings highlight the importance of selecting an extreme value distribution that is well-suited to the characteristics of the available dataset, thereby improving the reliability and accuracy of design wave height estimations for offshore engineering applications.1
SEDIMENT PARTICLE SEPARATOR
No full text본 장치는 퇴적물의 입자를 분리하기 위한 장치로서 인력으로 운용하던 기존 장비를 일정부분 자동화 하
여 실험자의 업무환경을 개선 및 발전시켜 효율적인 시간분배를 가능하게끔 하는 효과를 기대할 수 있다.
또한 핵심 과정을 장치를 동해 자동으로 진행되게끔 하여 숙련자와 비숙련자의 격차를 줄여 업무 접근성
의 향상또한 가져 올 수있을것이라 보인다
Dominant contribution of land-based aquaculture to coastal organic matter and nutrient loads: Quantifying particulate organic carbon and ammonium fluxes from Jeju Island, South Korea
No full textLand-based aquaculture farms (LAFs) are rapidly expanding on Jeju Island, South Korea, raising concerns about their environmental impact on coastal ecosystems. However, the quantitative contribution of LAFs to coastal nutrient loading remains inadequately understood. This study quantified the net fluxes of key pollutants from LAFs on Jeju Island by measuring concentrations of particulate organic carbon (POC), dissolved organic carbon (DOC), and dissolved inorganic nutrients (DIN, DIP, DSi) in the influent and effluent of four representative farms during the spring, summer, and autumn of 2019. Although the effluent concentrations of DOC, DIN, DIP, and DSi were comparable to influent levels, POC and ammonium (NH₄⁺) concentrations were significantly higher in the effluent (66 ± 24 µM and 24 ± 12 µM, respectively) than in the influent (7.5 ± 1.0 µM and 0.8 ± 0.2 µM, respectively), identifying them as primary pollutants associated with aquaculture activities. Effluent POC concentrations peaked in the summer, coinciding with increased feeding rates. Time-series observations capturing feeding-induced variations were used to estimate the net annual fluxes of POC and NH₄⁺ from all LAFs on Jeju Island at 35.7 × 10⁷ mol yr−1 and 16.6 × 10⁷ mol yr−1, respectively. Notably, the NH₄⁺ flux from LAFs was approximately 10 times greater than the combined fluxes from submarine groundwater discharge (SGD) and wastewater treatment plants (WWTPs), establishing LAFs as the primary source of bioavailable nitrogen in the coastal waters of Jeju Island. These findings highlight the urgent necessity for revising current environmental regulations by implementing nutrient-specific standards for aquaculture effluent to mitigate eutrophication and protect the ecological integrity of coastal ecosystems on Jeju Island.11Nsciescopu
Paleoceanographic evolution of surface and bottom waters at the Conrad Rise in the Indian sector of the Southern Ocean since the Last Glacial Maximum
No full textHigh-resolution multi-proxy paleoceanographic data were acquired using a 10.47 m long piston core (COR-1bPC) at the Conrad Rise located south of the Antarctic Polar Front (i.e., Antarctic Zone) in the Indian sector of the Southern Ocean. Twenty-two AMS 14C datings of planktonic foraminifera and the tuning between δ18O values of planktonic foraminifera and EPICA-Dome C ice core established the robust chronology that records about 43,000 cal yr BP. In addition to sediment properties (lightness and magnetic susceptibility), multi-proxy paleoceanographic records exhibit the distinct temporal variation of surface and bottom water properties from the last glacial through deglacial to Holocene. Biogenic opal and CaCO3 contents show an increase of surface water productivity from the last glacial period to the Holocene, attributable to the reduced sea ice coverage and more nutrient supply by resumed upwelling of Circumpolar Deep Water, which is similar to other sectors of Antarctic Zone. The extremely low CaCO3 content during the last glacial period indicates that bottom waters were more corrosive and the severe carbonate dissolution is related to the slow ventilation of global circulation (Lower Circumpolar Deep Water, North Atlantic Deep Water, and Antarctic Bottom Water). The opposite variation between TOC and TN contents and biogenic opal and CaCO3 contents is unexpectedly unusual, suggesting that the preservation of organic matter is more influenced by the bottom waters oxygenation rather than the export production. Furthermore, C/N ratios and δ13C values of sediment organic matter show differential degradation of organic matter between the last glacial period and Holocene, confirming the significant role of bottom waters oxygenation. Thus, organic carbon storing in the Antarctic Zone of the Southern Ocean is primarily influenced by global circulation and ventilation patterns as well as the accumulation of respired CO2, alongside the strength and efficiency of the biological pump.11Nsciescopusothe
Analytical Study of the Structural Performance of Tetrapods with Fiber-Reinforced Concrete
No full text테트라포드는 일반적으로 무근콘크리트로 제작되어 취성적 거동을 보인다. 이러한 파괴 양상을 개선하고 균열 저항성을 증진시키기 위한 방안으로 섬유보강 콘크리트를 사용하는 것이 대안 중 하나가 될 수 있다. 본 연구에서는 유한요소해석을 통해 섬유보강 콘크리트를 적용한 테트라포드의 구조성능을 평가하는데 중점을 두었다. 이를 위해 기존 연구자들의 실험 결과와 비교하여 유한요소모델을 검증하였으며 이후 변수해석을 진행하였다. 변수해석의 주요 변수는 섬유보강 콘크리트의 파괴에너지로 설정하였다. 문헌조사를 통해 다양한 섬유보강 콘크리트의 파괴에너지 범위를 도출하고 이를 변수해석에 적용하였다. 해석 결과, 테트라포드의 파괴는 균열에 의한 인장 파괴가 지배하는 것으로 나타났으며, 섬유보강 콘크리트의 사용은 테트라포드의 연성을 향상시킬 수 있는 것으로 확인되었다.
Tetrapods are typically constructed using plain concrete, which exhibits brittle failure behavior. To address this issue and enhance crack resistance, fiber-reinforced concrete (FRC) has emerged as a promising alternative. This study evaluates the structural performance of tetrapods incorporating FRC employing finite element analysis (FEA). The proposed numerical model was validated against experimental results from previous studies. A subsequent parametric study was conducted with the fracture energy of FRC as the primary variable. A representative range of fracture energy values, identified via a comprehensive literature review, was applied in the simulations. The results demonstrate that tensile cracking is the dominant failure mode in tetrapods, and that the incorporation of FRC significantly improves their ductility.22Nkc
Implementation of a circular bioeconomy: high-value resources from fish head waste
No full textThe issue of fish waste represents a significant challenge for the environment and the economy, with implications across the entire aquatic food value chain, from the initial catch to the final stage of consumption. This underscores the imperative for exploring alternative approaches to generating value from fish waste, with the objective of ensuring the sustainable utilisation of marine resources. A transition is necessary from the production of conventional, low-market-value commodities, and opportunities for the development of high-value products must be identified. One such effective approach is the production of peptone, a soluble protein hydrolysate that is commonly used as a microbial growth medium. The potential applications of peptone are diverse, extending to biotechnology, pharmaceuticals, and various industrial sectors.
This study specifically examined the utilisation of fish heads, which are often discarded during the processing stage, as a raw material for the generation of peptone. The proteins from fish heads were subjected to enzymatic hydrolysis under optimal conditions to produce peptone. The chemical properties of the resulting peptones were analysed, and their cell growth, recombinant protein productivity and biological activity were compared to those of other commercially available peptones. Furthermore, a cost-effective method for producing proteases was developed, with the aim of reducing the cost of peptone production. This approach demonstrates how resources that would otherwise be discarded can be transformed into high-value industrial products.2
Growth enhancement and gonadal development disruption using 500-nm LED light in commercial-scale Olive flounder (Paralichthys olivaceus) aquaculture
No full textLight manipulation in aquaculture offers potential for optimizing both growth and reproduction, yet the specific effects of monochromatic light in commercial-scale settings remain poorly understood. This study investigated the impact of 500-nm light-emitting diode (LED) light (13L:11D) on female olive flounders in a commercial-scale aquaculture setting over one year. Fish exposed to 500-nm light showed significantly higher body weights and condition factors compared to those under natural light. Growth enhancement was accompanied by elevated transcript levels of insulin-like growth factor-1 gene (Igf-1) in liver from October to February and increased hypothalamic melanin-concentrating hormone gene (MCH) expression from December to April. The treatment group exhibited suppressed reproductive development, evidenced by significantly lower gonado somatic index (GSI) values from October to February and delayed ovarian maturation. Histological analysis revealed that while the control group ovaries contained late vitellogenic oocytes in February, the 500-nm group maintained early vitellogenic stages. This reproductive delay corresponded with reduced expression of follicle-stimulating hormone β (fshβ) and luteinizing hormone β subunit (lhβ) genes in the pituitary gland and decreased ovarian cytochrome P450 family 19 subfamily A gene (cyp19a) levels during both spawning and non-spawning seasons. Notably, aralkylamine N-acetyltransferase (aanat1) transcript levels were significantly elevated in October and December under 500-nm light, suggesting altered melatonin-mediated regulation of physiological rhythms. These findings demonstrate that 500-nm LED lighting with 13L:11D photoperiod effectively enhances growth while suppressing reproductive development in commercial-scale olive flounder aquaculture, offering a practical alternative to traditional methods like triploid induction for managing the growth-reproduction trade-off in female olive flounders.11Nsciescopu
Method For Calculating Sea Surface Temperature And A Computer-Readable Medium Storing Program For Perform The Same
No full text위성 데이터를 획득하는 단계
서로 다른 위치에 설치된 다수 개의 부이로부터 부이 데이터를 획득하는 단계
위성 데이터를 기 설정된 간격으로 분할하는 단계
분할된 위성 데이터에서 대표 데이터를 선정하는 단계 및
분할된 위성 데이터에 상기 부이 데이터를 대입한 후 인터폴레이션 하는 단계 를 포함하는 공백없는 해수
면온도 생산기법.
QC 알고리즘이 이용되어 부이 데이터를 전처리하는 단계 를 더 포함하고,
상기 인터폴레이션 하는 단계에서 전처리된 부이 데이터가 분할된 위성 데이터에 대입되는 것을 특징으로
하는 공백없는 해수면온도 생산기법