• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.129-138
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• 2024

This study examines the osteological development of the Pike gudgeon, Pseudogobio esocinus in the cranial, vertebral, caudal, pelvic and pectoral girdle for the purpose of taxonomic and aquacultural studies. Adult Pike gudgeon collected from the Boseonggang River were reared at 18.5~19.5℃ (average 19.0℃). At 5 days after hatching (total length (TL) 4.25 mm), the parasphenoid, dentary, centrum of vertebrae and clavicle began to ossify. At 22 days after hatching (TL 6.33 mm), 36 to 38 vertebrae had ossified. At 42 days after hatching (TL 16.71 mm), the majority of the skeleton had ossified. Pike gudgeon exhibited comparable characteristics to other fishes of Gobionidae throughout its development, although it displayed differences in some areas, such as the caudal skeleton and fin supports.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.1
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• pp.67-72
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• 2017

This study developed an electric power propulsion personal watercraft by combining a battery and an electric system from the domestic automobile industry with water motorcycle from marine leisure industry in a convergence of technology. It also developed a safety inspection plan and type approval standard for personal watercraft that use electric power propulsion. For the registration and production of the electric power PWC (Personal Watercraft), a safety inspection standard (draft) and type approval standard (draft) have been established. PWC that use this electric power propulsion certification standard have been divided into two categories according to the use of gasoline engines as related to the ship's electrical system. The contents of these safety inspections standards is divided into 7 categories, and their purpose is to confirm the facilities used for the safe operation of PWC. Type approval is divided into 7 categories and is intended to ensure the safe production of PWC. This is basic data can be used to establish criteria for safety inspection and type approval of electric power propulsion vessels and to guide the production of the environmentally friendly PWC in Korea.

• Korean Journal of Ichthyology
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• v.36 no.1
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• pp.20-29
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• 2024

Hemitripterus villosus, a promising aquaculture fish species, is facing declining stocks. This study aims to provide normative standards for skeletal development to address persistent skeletal deformities in farmed fish. Specimens utilized in the study underwent artificial insemination with captured fish, and the resulting larvae and fry were preserved in a formalin solution. The skeletal ossification process commenced immediately after hatching, affecting the parasphenoid, premaxillary, maxillary, and dentary structures at an average total length of 13.65±0.71 mm (n=5). By sixty-five days post-hatching, ossification extended to the ethmoid and supraorbital, completing the head's development at an average total length of 21.24±0.50 mm (n=5). Clavicle ossification occurred at seven days post-hatching, corresponding to an average total length of 14.61±0.52 mm (n=5). At forty-four days post-hatching, the ossification of 4 actinosts took place, completing the shoulder girdle, with an average total length of 18.15±0.61 mm (n=5). Vertebral ossification initiated at ten days post-hatching, with an average total length of 14.80±0.65 mm (n=5). By fifty-four days post-hatching, 39 vertebral columns were ossified, reaching an average total length of 18.67±0.54 mm (n=5). Vertebral development was complete at sixty days post-hatching, with an average total length of 20.25±0.45 mm (n=5). This study sheds light on the skeletal development of H. villosus, providing valuable standards and fundamental data for understanding skeletal deformities in this species.

• Composites Research
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• v.35 no.5
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• pp.347-358
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• 2022

Carbon fiber is an excellent structural material, which has been proven in many industries, and the shipbuilding industry is no exception. In particular, in advanced maritime countries, special ships of the Navy and Coast Guard with carbon fiber composite hulls have already been deployed. In Korea, carbon fiber composite materials have been applied to a 10-ton class leisure craft or a 30-ton class patrol, but no research has been done on a hundred of tons or more vessels. In this study, the feasibility study of a 500-ton patrol vessel with a carbon fiber composite hull was conducted through an analysis of similar cases abroad. As a result, it was recognized that the developed hull can be reduced in weight by about 21% to 25% compared to the existing aluminum or FRP hull. It was also confirmed that this light-weight effect can induce the improvement of the maximum speed and the improvement of the operating range via simulations.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.603-614
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• 2021

Recently, the surface temperature in the seas around Korea has been continuously rising. This temperature rise causes changes in fishery resources and affects leisure activities such as fishing. In particular, high temperatures lead to the occurrence of red tides, causing severe damage to ocean industries such as aquaculture. Meanwhile, changes in sea temperature are closely related to military operation to detect submarines. This is because the degree of diffraction, refraction, or reflection of sound waves used to detect submarines varies depending on the ocean mixed layer. Currently, research on the prediction of changes in sea water temperature is being actively conducted. However, existing research is focused on predicting only the surface temperature of the ocean, so it is difficult to identify fishery resources according to depth and apply them to military operations such as submarine detection. Therefore, in this study, we predicted the temperature of the ocean mixed layer at a depth of 38m by using temperature data for each water depth in the upper mixed layer and meteorological data such as temperature, atmospheric pressure, and sunlight that are related to the surface temperature. The data used are meteorological data and sea temperature data by water depth observed from 2016 to 2020 at the IEODO Ocean Research Station. In order to increase the accuracy and efficiency of prediction, LSTM (Long Short-Term Memory), which is known to be suitable for time series data among deep learning techniques, was used. As a result of the experiment, in the daily prediction, the RMSE (Root Mean Square Error) of the model using temperature, atmospheric pressure, and sunlight data together was 0.473. On the other hand, the RMSE of the model using only the surface temperature was 0.631. These results confirm that the model using meteorological data together shows better performance in predicting the temperature of the upper ocean mixed layer.

• Journal of Korea Entertainment Industry Association
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• v.14 no.4
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• pp.289-303
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• 2020

The purpose of this study is to provide adequate datas on number of people who are in golf related field and also further expend that number for golf industry. The main stream of this study is to map out present golf related jobs and how this study can help golf industry in general. To make a greater improvements on golf industry with more job opportunity following ideas were presented. First, improving education on "hand on experiences on the field of golf industry" Better educating potential employees for golf industry for the right positions can enhance overall work environment. To do so, the society and the schools must come to agreement to provide adequate curriculum for people. Second, implementing "a golf club division program." The support from Ministry of Culture and Sports and Tourism Department, which are govern by Republic of Korea, are aggressively working to expend the golf business and also recruit elite personnel like former tour players to work on the field to better operate the whole system. Third, performing a thorough research on current golf related jobs and numbers and diversity on the field. Fourth, developing a specific and a differentiated golf job fields for better future for people and students who majored in golf industry. So that they cam feel secured and have a sense of dignity. Finally, strengthening the golf industry's competitiveness. The golf related companies have to step up to higher gear. With working in harmony between golf industry and government can assure of brighter future for our next generation.

• Korean Journal of Ichthyology
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• v.35 no.2
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• pp.83-90
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• 2023

Five days after hatching in Konosirus punctatus, the larvae were 5.86~6.21 mm (mean 5.96 mm) in TL and ossified parasphenoid, prefrontal, premaxillary, dentary. Sixteen days after hatching, the larvae were 9.66~10.18 mm (mean 9.96 mm) in TL and ossified prootic, opisthotic, ectopterygoid, and epihyal. Twenty-five days after hatching, the larvae were 11.02~12.64 mm (mean 11.03 mm) in TL and ossified supraclavicle, posttemporal, four actinost. Twenty-eight days after hatching, the larvae were 11.98~12.81 mm (mean 12.34 mm) in TL and ossified frontal, pterotic, epiotic, exoccipital, basioccipital, preorbital, maxillary, hyomadibular, preopercle, opercle, hypohyal. Thirty-six days after hatching, the larvae were 15.26~16.39 mm (mean 16.11 mm) in TL and ossified scapula. 37 days after hatching, the larvae were 15.33~16.87 mm (mean 16.25 mm) in TL and ossified ethmoid, nasal, parietal, supraoccipital, and suborbital. Forty-five days after hatching, the larvae were 20.01~21.83 mm (mean 21.14 mm) in TL, and the shoulder girdle was completed by coracoid formation. Forty-eight days after hatching, the larvae were 22.46~24.03 mm (mean 23.20 mm) in TL and ossified articular and subopercle. When the juvenile reached 27.11~34.09 mm (mean 30.11 mm) in TL (53 days after hatching) completed ossification of the cranium, vertebrae, pelvic girdle, shoulder girdle, caudal bone, and pterygiophore.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.141-152
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• 2011

The fluctuation of inundation height due to climate change and sea level rise is expected to cause the socio-economical damage in the coastal zone. To evaluate the inundation damage in Haeundae Beach Area, the inundation height was calculated using the observed data and the range of inundated area and buildings was estimated by applying to DEM data, which was constructed with airborne LiDAR data. The range of inundated area and buildings were estimated with 5 scenario of sea level rise in the condition of minimum and maximum inundation height. When the 181cm, the area of 7.19ha and 5 buildings were expected to be inundated. As 20cm in sea level rises at the minimum of the inundation height, the area of 8.90ha and 8buildings were expected to be inundated. As 30cm, 40cm, 50cm, 60cm in sea level rise, 9.98ha and 9 buildings, 11.11ha and 11buildings, 12.41ha and 11buildings, 14.18ha and 14buildings were expected to be inundated, respectively. When the 526 cm, the area of 32.35ha and 42buildings were expected to be inundated. As 20cm, 30cm, 40cm, 50cm, 60cm in sea level rise at the maximum of the inundation height, 38.94ha and 47buildings, 42.46ha and 52buildings, 45.76ha and 58buildings, 49.51ha and 66buildings, 52.53ha and 72buildings were expected to be inundated, respectively. The leisure and industry facilities, socio-economical installation, habitation are located near by the estimated inundation area, then the inundation damage is expected to be greater scale.

• Korean Journal of Ichthyology
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• v.36 no.1
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• pp.30-39
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• 2024

This study examines the osteological development of the Bartail Flathead Platycephalus indicus in the cranial, vertebral, caudal bones and pelvic, sholder grilde bones for the purpose of taxonomic studies. Adult P. indicus were collected from the Yeosu coast and artificially fertilized. Juveniles were reared at 18.5~21.8℃ (average 20.0℃±0.5℃). At 3 days after hatching (total length (TL) 3.49±0.32 mm), the parasphenoid and clavicle began to ossify. At 14 days after hatching (6.34±0.24 mm), the parietal and exoccipital bones of the cranium, the six branchiostegal rays of the hyoid, the urostyle of the caudal bones and the actinost of the shoulder girdle had ossified. At 39 days after hatching (11.39±0.86 mm), the preorbital and suborbital bones of the cranium were ossified, ossification of the pelvis girdle had begun, and the sholuder girdle was fully ossified. The number of vertebral columns were 26. At 45 days after hatching (12.63±0.62 mm), the nasal and supraorbital bones were ossified and the entire skeleton of the juvenile was completely ossified.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.174-181
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• 2024

This study examines the community characteristics of fish species collected by fyke net from the eastern coastal waters of Yeosu, Korea, during the period from 2020 to 2021. A total of 4,539 fish were sampled and classified into 43 species, 28 families, and 7 orders. The dominant species included Mugil cephalus (14.4%), Konosirus punctatus (10.9%), Lateolabrax japonicus (8.3%), Acanthopagrus schlegelii (7.9%), and Pennahia argentata (7.2%). The diversity index was highest in October (H'=2.888) and lowest in February (H'=2.075). Furthermore, the dominance index was highest in March (DI=0.524) and lowest in December (DI=0.178). Hierarchical cluster analysis (HCA) revealed that fish communities could be divided into three groups based on Bray-Curtis similarity. Group 1, consisting mainly of species collected from June to October, formed one cluster. Group 2, including winter spawning species such as Pseudopleuronectes yokohamae, Clupea pallasii, and Hexagrammos otakii, sampled from November to February, formed another cluster. Group 3, which included species such as Larimichthys polyactis, Amblychaeturichthys hexanema, and Sebastes inermis, formed a cluster collected from March to May. The eastern coast of Yeosu is considered a suitable habitat for fisheries resources, including highly economically valuable species, and it is also assumed to be an important spawning and nursery ground for many fish species.