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Synthetic Training Data Optimization for Enhanced Fault Detection in Seismic Images
No full textThis study presents a parameter optimization strategy for generating synthetic seismic data that closely match the characteristics of target field data, aiming to improve deep learning-based fault detection. An analysis in the latent space is conducted to assess the similarities between synthetic data and target field data. Based on the results from this analysis, we optimize the parameters for generating synthetic data. Further refinement of the data generation process is achieved through the application of Explainable Artificial Intelligence (XAI). The fault interpretation results using the U-Net model trained on optimized synthetic data show significant improvements compared to those from the model trained on unoptimized data. The optimization strategy employed allows for the visualization of feature distributions in the latent space, offering a direct understanding of how the distribution of features shifts depending on the desired parameters. This approach not only circumvents the limitations associated with using field data for training, such as the challenge of acquiring accurate fault structure labels and the scarcity of sufficient training data, but also overcomes the potential discrepancies in interpretation results due to significant deviations in the characteristics of synthetic data from the target field data. The proposed optimization framework improves the performance of deep learning models in fault interpretation and establishes an advanced approach for using synthetic data in deep learning-based seismic interpretation.11Ysciescopu
Global warming impacts on marine diversity and key indicator species in East Asia
No full textMarine ecosystems in the northwest Pacific are known for theirhigh biodiversity, with many marine species, from tiny planktonto huge macroalgae. Marine biodiversity is affected by irreversibleglobal warming, mainly the increase of greenhouse gas emissionsfrom anthropogenic activities. For the past several decades, marineecosystems in East Asia have been changing due to the increase in seasurface temperature (SST), which has changed some important en-vironmental factors, including rainfall patterns, extreme weather,and ocean circulation. Such modifications in the environmentalparameters have altered the physiology, phenology, and distributionpattern of marine organisms. The SST increase has also alteredpopulation and community structure, and the functioning of theecosystem. Certain subtropical and tropical fauna and flora arenow extending their range of distribution from the warm southernarea to the temperate regions, disrupting or modifying the bioticinteractions in the temperate ecosystem. Collaborative conserva-tion projects and responsible policies are crucial to safeguard theenvironmental value of East Asia’s marine ecosystems for futuregenerations and mitigate the negative effects of global warmingon marine biodiversity. Conservation and management of EastAsia’s marine environments hold significant implications for globalbiodiversity and ecological balance, making them a pivotal focus inaddressing climate change challenges in marine ecosystems.33Yscopu
상반전 조류발전 터빈의 매개변수 분석 연구
No full text조류발전은 조석 현상에 의해 발생되는 조류의 흐름을 이용하여 전기를 생산하는 재생에너지 발전방식이다. 조류발전은 다른 재생에너지 발전과 비교하여 규칙적인 조류의 특성을 이용하기 때문에 장기간 발전량을 비교적 정확하게 예측할 수 있다는 장점을 가지고 있다. 특히 조류발전시스템 중 상반전 조류발전 터빈은 하나의 터빈에 두 개의 로터가 조류 흐름 방향에 대해 전방과 후방에 위치하여 서로 반대 방향으로 회전하는 방식으로, 단일 로터를 갖는 터빈과 비교하여 상대 회전수가 증가하기 때문에 발전 효율이 향상되고 나셀에 작용하는 회전 모멘트가 줄어드는 효과를 기대할 수 있다. 이러한 기계적 특성과 유체역학적 장점은 터빈 로터의 직경을 줄일 수 있는 설계가 가능하고, 결과적으로 나셀 및 지지구조물의 규모와 비용을 절감하는데 기여할 수 있다. 본 연구에서는 BEMT(Blade Element Momentum Theory)에 기반하여 상반전 조류발전 터빈 블레이드의 기본설계를 수행하고 삼차원 비정상 레이놀즈 평균 나비어-스톡스 해석에 기반하여 유동특성 분석 및 출력 성능을 예측하였다. 상반전 조류발전 터빈의 출력계수와 토크계수에 대한 전방 로터와 후방 로터의 상대적 거리와 주속비, 그리고 로터 블레이드의 피치각도 변화의 영향을 확인하였다. 이러한 상관관계를 규명함으로써 상반전 조류발전 터빈의 성능 최적화 가능성을 제시하였다.2
산란기 참조기(Larim ichthys polyactis) 소리의 음향학적 특성 분석 및 재현 연구
No full text해양생물음은 수중에서 은밀 통신 등 다양한 분야에 활용될 수 있다[1]. 이러한 해양생물음은 종에 따라 고유한 음향학적 특성을 가지므로, 개별 어종에 대한 음향학적 특성 분석 및 이를 기반으로 한 재현이 필요하다.
본 연구는 산란기 참조기(Larimichthys polyactis) 소리의 음향학적 특성을 분석하고 분석 결과를 바탕으로 참조기 소리를 재현하였다. 참조기 소리는 약 500-700 Hz 범위에서 에너지가 우세하게 분포하며, 짧은 펄스(pulse)들이 약 20-120 ms 간격으로 수-수십 회 반복되는 펄스열로 나타나는 것이 확인되었다. 시간 영역에서 웨이블렛(wavelet)을 합성하여 개별 펄스를 모의하였으며, 측정된 펄스 간 간격 및 반복 횟수를 바탕으로 참조기 소리를 재현하였다. 재현 신호와 측정된
참조기 소리의 유사도는 피어슨 상관계수를 이용하여 평가하였으며, 평균 약 0.96의 높은 유사도를 보였다.2
Effects of cobalt rich ferromanganese crust on gut microbiome in the marine medaka Oryzias melastigma
No full textDeep-sea mineral deposits have gained significant attention as terrestrial resources become increasingly depleted. One such deposit, cobalt-rich ferromanganese (Fe-Mn) crusts, is distributed along the slopes of seamounts at depths ranging from 600 m to 7,000 m. Fe-Mn crusts contain high concentrations of rare-earth elements, which are essential for various industries, including semiconductor manufacturing. However, the potential ecological impacts of deep-sea mining on marine organisms remain largely unexplored. This study evaluates the environmental effects of Fe-Mn crust leachate and particles on the marine medaka Oryzias melastigma, an experimental species proposed by the International Seabed Authority (ISA). The experiment included four treatment groups: a control group, two particle exposure groups, and a leachate exposure group. The results indicated no significant effects on survival or hatching rates in the in vivo toxicity test. However, distinct alterations in gut microbiota composition were observed across the treatment groups, with more pronounced changes in the particle exposure groups. These findings suggest that metals constituting Fe-Mn crusts can influence gut microbial communities in fish, and the effects vary depending on the type of exposure. In particular, the physical effects of particles may play a crucial role in shaping microbial communities. Fish serve as a crucial trophic link between primary producers, primary consumers, and higher predators, including humans. This study demonstrated that exposure to Fe-Mn crusts leads to decreased fish health by altering the microbiota. Therefore, ferromanganese crust mining may impact fish populations, which could, in turn, affect the oceanic food web.2
De novo transcriptome profiling of Pandalopsis japonica including microRNAs
No full textPandalopsis japonica (P. japonica) inhabits in the East Sea of Korea. P. japonica is a significant economic species for its commercial importance in Korea. Due to the absence of genomic resources, we performed Illumina sequencing to estimate its genome size at approximately 14-15Gb. Moreover, de novo transcriptome assembly was achieved through Pacbio RNA isoform sequencing, Illumina RNA sequencing, and small RNA sequencing. This led to the establishment of 18,769 unigenes, among which 11,329 genes were annotated through various methods. As a result of performing differentially expressed genes analysis, 2,584 genes were found to be differentially expressed in the hepatopancreas compared to the muscle. The results of small RNA sequencing were mapped to 5 model species, identifying 423 orthologous miRNAs, with miRDeep2 predicting stem-loop structures for 42 novel miRNAs. Taken together, this study presents the first-ever de novo ranscriptome analysis of P. japonica, offering essential genomic information for future functional studies in P. japonica.2
A New Family of Cyclopoid Copepods (Nodocopsidae) Associated with Corals from Deep-Sea Seamounts in the West Pacific, with Descriptions of Five New Species
No full textA new lichomolgoid family, Nodocopsidae, is established to accommodate five new species in three new genera associated with corals inhabiting deep-sea seamounts in the West Pacific. The most significant apomorphic feature of the new family is the loss of mandibles. As other characteristic features of the new family, the first antennular segment bears at most three setae, the antenna is four-segmented with four setae on the second endopodal segment and one to four claws plus setae on the third endopodal segment, the maxilla exhibits functional replacement of the mandible of other lichomolgoid copepods with its distal segment bearing a well-developed distal lash and a large inner seta, the labrum is well-developed with a pair of lobes on its posterior margin, the labium is distinct, the female maxilliped is two-segmented with three setae on its distal segment, and the last endopodal segment of leg 4 is armed with two or three spines only. The three new genera are distinguished from one another by differences in the number of terminal claws on the antenna: four in Nodocops n. gen., one in Paranodocops n. gen., and three in Musenota n. gen. Musenota n. gen. is represented by three new species, which differ in the segmentation and armature of swimming legs. A key for the identification of the five new species is provided.22Ykc
A New Species of Tetragoniceps (Harpacticoida, Tetragonicipitidae) from Korea
No full textA new harpacticoid species belonging to the genus Tetragoniceps Brady & Robertson, 1880 was discovered in subtidal sandy sediments off Dokdo Island in the East Sea. The new species is assigned to the genus Tetragoniceps based on key morphological characteristics, including an elongated first antennular segment with a hook-shaped projection on its outer distal margin, two-segmented endopods and three-segmented exopods on legs 1–4, and a non-foliaceous leg 5 in the female. Among the 17 known congeners, the new species most closely resembles T. bergensis Por, 1965, sharing the armature pattern of the endopods of legs 1–4 and the terminal exopodal segments of legs 2–4, which bear 6, 5, and 7 setae or spines, respectively. However, it differs from T. bergensis in possessing an inner seta on the first exopodal segment of legs 2–4 (vs. absent in T. bergensis), an additional seta on both rami of the female leg 5, a one-segmented exopod on the male leg 5 (vs. two-segmented in T. bergensis), and caudal rami with a length-to-width ratio of 3:1 (vs. approximately 6:1 in T. bergensis). This study represents the first record of the genus Tetragoniceps from Korean waters.2
Enhanced Cell Growth and Hydrogen Production through Overexpression of a Transcriptional Regulator in Thermococcus onnurineus NA1
No full textEnfR (TON_1525), a Tfx family DNA-binding protein, has been recognized as a key factor for adaptation to carbon monoxide (CO) in Thermococcus onnurineus NA1. It plays a role as a transcriptional regulator that represses the expression of the codh-mch-mnh3 gene cluster, which is involved in CO oxidation and subsequent hydrogen (H2) production. In our previous report, transcriptome analysis of a deletion mutant lacking TON_1525 revealed that EnfR may also regulate other metabolic processes. Specifically, the transcript levels of the gene cluster containing genes encoding a formate dehydrogenase (Fdh2), a membrane-bound hydrogenase (Mfh2), and a cation/proton antiporter (Mnh2), essential for utilizing formate for growth and ATP production, were significantly reduced in the mutant. Consequently, this mutant exhibited growth defects when cultured with formate as its energy source. Based on these findings, it was hypothesized that overexpressing EnfR could improve formate metabolism. In this study, an EnfR overexpression mutant was constructed and its physiological impact was assessed by cultivating it in formate-supplemented medium. In comparison to the parental strain, the overexpression strain showed significant increases in both cell density and H2 production rate. However, Western blot analysis indicated that the protein expression level of Fdh2 was not increased. To determine which specific genes or pathways were affected by the deletion of TON_1525 and how they contribute to the observed physiological changes, a comprehensive analysis of the transcriptome was performed. This study provides valuable insights into the potential of employing a transcriptional engineering strategy to improve formate metabolism in T. onnurineus NA1.1