• Korean Journal of Fisheries and Aquatic Sciences
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• v.54 no.2
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• pp.194-207
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• 2021

It is necessary to assess and manage the different elements of the marine ecosystem, such as climate change, habitat, primary and secondary production, energy flow, food web, potential yield, and fishing, to maintain the health of the ecosystem as well as support sustainable development of fishery. We set up an ecosystem model around the Korean peninsula to produce scientific predictions necessary for the assessment and management of marine ecosystems and presented the usability of the model with scenario experiments. We used the Atlantis ecosystem model based on the marine food web; Atlantis is a three-dimensional end-to-end model that includes the information and processes within an entire system, from an abiotic environment to human activity. We input the ecological and biological parameters, such as growth, mortality, spawning, recruitment, and migration, to the Atlantis model via functional groups using existing research and local measurements. During the simulation period (2018-2019), we confirmed that the model reproduced the observed data reasonably and reflected the actual ecosystem characteristics appropriately. We thus identified the usability of a marine ecosystem model with experiments on different environmental change scenarios.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.59-75
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• 2012

The species composition of plankton is essential to understand the material and energy cycling within marine ecosystem. It also provides the useful information for understanding the properties of marine environments due to its sensitivity to the physicochemical characteristics and variability of water masses. In this study we adopted metagenomics to evaluate eukaryotic plankton species diversity from coastal waters off Busan. Characteristics of water masses at sampling sites is expected to be very complex due to the mixing of various water masses; Nakdong River runoff, Changjiang diluted water (CDW), South Sea coastal water, and Tsushima warm current. 18S rDNA clone libraries were constructed from surface waters at the three sites off Busan. Clone libraries revealed 94 unique phylotypes from 370 clones; Dinophyceae(42 phylotypes), Ciliophora(15 phylotypes), Bacillariophyta(7 phylotypes), Chlorophyta(2 phylotypes), Haptophyceae(1 phylotype), Metazoa(Arthropoda( 17 phylotypes), Chaetognatha(1 phylotypes), Cnidaria(2 phylotypes), Chordata(1 phylotype)), Rhizaria (Acantharea(2 phylotypes), Polycystinea(1 phylotype)), Telonemida(1 phylotype), Fungi(2 phylotypes). The difference in species diversity at the closely located three sites off Busan may be attributed to the various physicochemical properties of water masses at these sites by the mixture of water masses of various origins. Metagenomic study of species composition may provide useful information for understanding marine ecosystem of coastal waters with various physicochemical properties in the near feature.

• Korean Journal of Environmental Agriculture
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• v.41 no.1
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• pp.65-70
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• 2022

BACKGROUND: The Geomunoreum Lava Tube System (GLTS) is both vast and culturally valuable. The Jeju Volcanic Island and Lava Tubes, which are partly composed of the GLTS, have been declared as a United Nations Educational, Scientific, and Cultural Organization (UNESCO) World Heritage Site. Exploration of the caves is strictly regulated to conserve these vulnerable environments. Photographs provide limited information and do not describe the entire environment comprehensively. Therefore, we created several illustrations of the lava tubes to display their environmental features. METHODS AND RESULTS: We explored six lava caves (upstream and downstream) in the GLTS and photographed their geological features and yellow walls, the colors of which are influenced by microbial mats. We compared the hex codes of the wall colors using the Clip Studio v1.10.5 software and created illustrations that accurately represent the scale and features of the caves. CONCLUSION(S): Upstream and downstream caves of the GLTS differ in scale and volcanic features. We illustrated various characteristics of the caves including lava cave features, vegetation, and microbial mats. We also described the internal and external cave environments.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.6 no.3
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• pp.141-147
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• 2013

An artificila fish-reef is a artificail structure installed at marine ranching under the littoral sea. The artificial fish-reefs provide the function of fish spawning ground, habitation, nursery ground, and enhance the productivity of fising industry devastated by environmental pollution. After the installation of artificila fish-reef, continuous monitoring is demanded to check the validity of artificila fish-reef plan. However, the support of follow-up management is impossible because of the lack of a huge budget and professional manpower. Therefore, the artificial fish-reef combined with IT devices can be controled IT devices through the IT artificial fish-reef management system, and collect the marine environment information for the fair management. This paper shows the example of systematization for the management of artificial fish-reef based on the marine rancing management system.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.7
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• pp.569-573
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• 2016

Strengthened regulations for atmospheric emissions from ships have created a need for new and alternative power systems that offer low emissions and high energy efficiency. Recently, new types of propulsion power systems, such as fuel cell systems that use hydrogen as an energy source, have gained serious consideration in applications requiring emission control. The purpose of this work is to certify the availability of solid oxide fuel cell (SOFC) systems equipped with recycled steam reforming fuel processors, and to compare their performance with that of extra steam reforming systems. The results demonstrate that the recycled steam reforming system has a slightly lower cell voltage and higher energy efficiency than the extra steam reforming system.

• Journal of Distribution Science
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• v.18 no.1
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• pp.15-26
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• 2020

Purpose: This study is to analyze the image classification using Convolution Neural Network and Transfer Learning for Jeju Island and to suggest related implications. As the biggest tourist destination in Korea, Jeju Island encounters environmental issues frequently caused by marine debris along the seaside. The ever-increasing volume of plastic waste requires multidirectional management and protection. Research design, data and methodology: In this study, the deep learning CNN algorithm was used to train a number of images from Jeju clean and polluted beaches. In the process of validating and testing pre-processed images, we attempted to explore their applicability to coastal tourism applications through probabilities of classifying images and predicting clean shores. Results: We transformed and augmented 194 small image dataset into 3,880 image data. The results of the pre-trained test set were 85%, 70% and 86%, and then its accuracy has increased through the process. We finally obtained a rapid convergence of 97.73% and 100% (20/20) in the actual training and validation sets. Conclusions: The tested algorithms are expected to implement in applications for tourism service distribution aimed at reducing coastal waste or in CCTVs as a detector or indicator for residents and tourists to protect clean beaches on Jeju Island.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.1
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• pp.11-20
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• 2010

Oyster production is playing an important role in domestic aquaculture, but facing some problems such as exports decrease, a slowdown in domestic demand and marine environmental deterioration. In order to obtain the suitable and sustainable oyster production, suitable sites selection is an important step in oyster aquaculture. This study was conducted to identify the suitable sites for lunging culture of oyster using Geographic Information System(GIS)-based multi-criteria evaluation methods. Most of the parameters were extracted by Inverse Distance Weighted(IDW) methods in GIS and eight parameters were grouped into two basic sub-models for oyster aquaculture, namely oyster growth sub-model(Sea Temperature, Salinity, Hydrodynamics, Chlorophyll-a) and environment sub-model(Bottom DO, TOC, Sediment AVS, Benthic Diversity). Suitability scores were ranked on a scale from 1(leased suitable) and 8(most suitable), and about 80.1% of the total potential area had the highest scores 5 and 6. These areas were shown to have the optimum condition for oyster culture in GeojeHansan Bay. This method to identify suitable sites for oyster culture may be used to develop bivalve culture management system for supporting a decision making.

• Animal Systematics, Evolution and Diversity
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• v.33 no.1
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• pp.8-16
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• 2017

We firstly described a box jellyfish, Carybdea brevipedalia collected from the southern coasts of Korea. It is morphologically characterized by gastric phacellae, a special digestive system of cubozoan jellyfish, and velarium, the thin muscle flap forming the opening of the subumbrellar cavity. The phacellae are linear-shaped, comprising numerous cirri branched from multiple roots. Each root also has multiple numbers of cirrus bundles. Basis of velarial cannels parts into two branches in each octant of velarium. Its geographic distributions were limited to Jeju-do and the middle-southern coasts where the organisms are seriously hazardous to bathers in summer. Numerous individuals and/or large-sized populations were observed specifically from beaches at Jeju-do, Namhae-do and a small fishing port of Namildae, while only a small amount of the individuals was observed in Gamak Bay, Jaran-Goseung Bay, and Geoje-do. We confirmed molecular identity of the Korean C. brevipedalia with comparison of nuclear ribosomal DNA sequences. Until now, Carybdea brevipedalia is the only cubozoan species reported to be distributed in Korean waters.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.100-103
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• 2023

Recently, development of maritime autonomoust surface ships and eco-friendly ships, production and evaluation research considering various marine environments is needed in the field of optimal routes as the demand for accurate and detailed real-time marine environment prediction information expands. An algorithm that can calculate the optimal route while reducing the risk of the marine environment and uncertainty in energy consumption in smart ships was developed in 2 stages. In the first stage, a profile was created by combining marine environmental information with ship location and status information within the Automatic Ship Identification System(AIS). In the second stage, a model was developed that could define the marine environment energy map using the configured profile results, A regression equation was generated by applying Random Forest among machine learning techniques to reflect about 600,000 data. The Random Forest coefficient of determination (R²) was 0.89, showing very high reliability. The Dijikstra shortest path algorithm was applied to the marine environment prediction at June 1 to 3, 2021, and to calculate the optimal safety route and express it on the map. The route calculated by the random forest regression model was streamlined, and the route was derived considering the state of the marine environment prediction information. The concept of route calculation based on real-time marine environment prediction information in this study is expected to be able to calculate a realistic and safe route that reflects the movement tendency of ships, and to be expanded to a range of economic, safety, and eco-friendliness evaluation models in the future.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.6
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• pp.1036-1043
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• 2022

This paper discusses about the development of a visual sensor that can be installed in an automatic mooring device to detect the berthing condition of a vessel. Despite controlling the ship's speed and confirming its location to prevent accidents while berthing a vessel, ship collision occurs at the pier every year, causing great economic and environmental damage. Therefore, it is important to develop a visual system that can quickly obtain the information on the speed and location of the vessel to ensure safety of the berthing vessel. In this study, a visual sensor was developed to observe a ship through an image while berthing, and to properly check the ship's status according to the surrounding environment. To obtain the adequacy of the visual sensor to be developed, the sensor characteristics were analyzed in terms of information provided from the existing sensors, that is, detection range, real-timeness, accuracy, and precision. Based on these analysis data, we developed a 3D visual module that can acquire information on objects in real time by conducting conceptual designs of LiDAR (Light Detection And Ranging) type 3D visual system, driving mechanism, and position and force controller for motion tilting system. Finally, performance evaluation of the control system and scan speed test were executed, and the effectiveness of the developed system was confirmed through experiments.