• Journal of Advanced Navigation Technology
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• v.26 no.5
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• pp.261-271
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• 2022

This paper is the study in Korea to secure new frequency resources available at sea among terrestrial DTV (Digital TV) broadcasting bands. Focusing on Incheon and Jejudo in the west Sea of Korea, the possibility of using TVWS frequencies of DTV broadcast signals (channels 14-51, 470~698 MHz) was studied. According to the analysis, three channels, channel 19 (503 MHz), channel 37 (611 MHz) and channel 39 (623 MHz) can be used as TVWS available channels without interference with DTV in all nearby seas such as Incheon Port and Jeju Port. On the other hand, two channels, Channel 23 (527 MHz) and Channel 33 (587 MHz), were divided into strong DTV signals in the section between Incheon Port and Jeju Port, making it difficult to use them as available frequencies for TVWS on the west coast.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.1
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• pp.99-108
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• 2023

In this study, changes in biofloc-related and pathogenic bacteria in both low and high concentration biofloc breeding water planted with the halophyte (Triglochin maritimum were investigated). In the low-concentration biofloc breeding water, the ratio of bacteria related to the nitrogen cycle was initially 59.57% and, it decreased to 26.57% at the end of the experiment while other bacteria (excluding nitrogen-cycling bacteria and vibrios) increased from 38.75% to 73.43%. However, the planted experimental group maintained a relatively high ratio of nitrogen cycling bacteria at 58%. In the high-concentration experimental group, bacteria related to the initial nitrogen cycle, non-pathogenic vibrios, and pathogenic vibrios were 11.60, 36.28, and 20.14%, respectively. Finally, nitrogen-cycling bacteria were 36.47% in the control group and 37.55% in the planted group. The total number of vibrios decreased by 46.54% in the planted group and 48.01% in the control group, indicating a significant decrease in both experimental groups. However, the residual rate of pathogenic vibrios was 4.48% in the control group and 0.54% in the planted group. Overall, the planted group showed decreasing harmful bacteria and increasing useful bacteria.

• Korean Journal of Ichthyology
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• v.36 no.2
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• pp.164-173
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• 2024

We collected fish from the intertidal zone of Seonyu-do Island in order to find out the composition of fish species by using hand net and kick net from March to October 2022. During the investigation period, a total of 2,707 individuals from 9 Orders, 19 Families, 45 Species were collected, and the dominant species was identified as Nuchequula nuchalis and the subdominant species was Favonigobius gymnauchen. By family group, the largest number of fishes in the Gobiidae were 13 species, followed by the Scorpaenidae and the Stichaeidae were 4 species. In this study, genus Clariger was discovered for the first time off the West sea, and it is estimated that fish living on the southern coast are moving northward due to an increase in the water temperature of the West Sea and detailed research is needed.

• Journal of Korea Port Economic Association
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• v.24 no.4
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• pp.139-152
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• 2008

China's rapid growth of economy and developing logistics facilities such as sea and air ports can give the good effects to increase the trade and logistics cargo volumes within Pan Yellow Sea Economic Bloc which consists of Korea, China, Japan and Russia. These phenomenon also stimulate the development of the West Coastal Integrated Belt in South Korea. In the past 20th century, South Korea's advanced and developed areas were located on the Kyeong-Bu Axis, the straight line of Seoul and Busan. However, due to the china's effect, this axis is moving into the West Coast area between Incheon (Seoul) and Mokpo, which is closely located to China. In this aspect, sea ports located in West Coast of Korea have shown the steep increase in container and non-container cargo volumes. With regard to the changing environments in sea ports, this paper's aim is to investigate the developing potential of Gunsan (Saemangum) area located on mid of West Coast. As results, targeted area have shown the potential in terms of port network, supply chain management and transferring location for container cargoes. Moreover, for implementing the suitable roles, construction of New Saemangun port, closely located in Gunsan port, is needed to overcome the limitations of Gunsan port.

• Environmental Analysis Health and Toxicology
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• v.22 no.4
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• pp.321-327
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• 2007

4-nonylphenol (4-NP)이 해산어류인 조피볼락, Sebastes schlegeli의 혈장 vitellogenin (VTG), alkaline-labile protein phosphorus (ALPP), calcium(Ca), glutamate pyruvate transaminase (GPT) 및 hepatosomatic index (HSI)에 미치는 영향을 조사하였다. 실험어에 3일간격으로 $estradiol-17{\beta}$ ($E_2$, 5 mg/kg B.W.) 또는 4-NP(0, 10, 50, 100및 200 mg/kg B.W.)을 복강에 2번 주사한 후, 7일째에 채혈과 적출을 통해 혈장과 간장을 수집해 분석이 실시되었다. 대조 실험어에는 용매로 사용된 70% 에탄올만이 투여되었다. $E_2$ 투여 실험어의 혈장 단백질을 전기 영동상으로 분석한 결과 약 170 kDa의 위치에서 짙은 VTG 밴드가 관찰되었으나, 용매만 투여한 대조 실험어의 혈장에서는 동일 밴드가 관찰되지 않았다. 4-NP 투여한 모든 실험어의 혈장 단백질에서는 $E_2$ 투여 실험어와 동일한 VTG 밴드가 관찰되었다. 혈장 ALPP와 Ca 농도도 4-NP 투여 실험어에서 $E_2$ 투여 실험어와 유사하게 증가하였으며, 이들 농도 변화는 VTG 합성과 더불어 증가하는 경향을 나타냈다. 혈장 전위효소인 GPT와 HSI도 $E_2$ 투여 실험어와 유사하게 4-NP가 투여된 모든 실험어에서 급격히 증가하였다. 이상의 결과로부터 연안생태계 내에서 서식하는 어류가 4-NP과 같은 내분비 장애물질(Endocrine Disrupting compounds, EDCs)에 의해 영향을 받는지를 규명하기 위한 생물학적 지표로서 VTG와 더불어 혈장 ALPP와 Ca이 사용가능 할 것으로 판단된다. 또한, 조피볼락과 같은 해산어가 EDCs에 노출되어 VTG가 합성될 때 간장 기능의 손상으로 혈장 전위효소인 GPT가 일시적으로 종가하고 간장도 비대해져 HSI가 높아지는 것으로 판단된다.

• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.3
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• pp.1-11
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• 2011

The temporal variability of spring (March, April, May) monthly precipitation, precipitation effectiveness, monthly maximum precipitation, monthly precipitation of different durations, and the precipitation days over several threshold (i.e. 0, 10, 20, 30, 40, and 50 mm/day) of 59 weather stations between 1973 and 2009 were analyzed. Also to analyze the regional characteristics of temporal variability, 59 weather stations were classified by elevations, latitudes, longitudes, river basins, inland or shore (east sea, south sea, west sea) area and the level of urbanization. Results demonstrated that trends of variables increase in April and decrease in May except precipitation day. Overall trend of precipitation amount and precipitation effectiveness is same but precipitation effectiveness of several sites decrease despite the trend of precipitation amount increases which may be caused by the air temperature increase. Therefore more effective water supply strategy is essential for Spring season. Regional characteristics of Spring precipitation variability can be summarized that increase trend during May become stronger with the increase of latitude and elevation which is similar to that of Summer season. The temporal variability of variables showed different behaviors according to river basins, inland or shore (east sea, south sea, west sea) area and the level of urbanization.

• Journal of Aquaculture
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• v.20 no.3
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• pp.147-153
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• 2007

The present study was performed to evaluate sitological quality of the cultured and wild river puffer, Takifugu obscurus. Proximate composition, the content of extractive nitrogen, the content of nucleotides and their related compounds, total and free amino acid, and fatty acids were analysed and sensory evaluation in the muscle of the river puffer were compared. The cultured river puffer had a higher moisture content compared to the wild fish, while there was no significant difference in crude lipid, crude protein and ash contents. Nucleotides and their related compounds including ATP, ADP, AMP, IMP, HxR and Hx were detected. The result from analyzing ATP-related compound showed difference in total content by wild and cultured river puffer, and IMP content that had largest influence upon the savory taste of sliced raw fish, was higher in the cultured fishes than wild ones. Breaking strength level of the wild river puffer was higher than that of the cultured fish. High levels of C16:0 and C18:0 were shown in all samples and -3 polyunsaturated fatty acid content were not different between the cultured and wild river puffers (P>0.05). Total 17 amino acids were detected in the samples, and most of the samples had high contents of glutamic acid, aspartic acid, lysine and leucine and low contents of cystine, histidine, methionine and tyrosine. The result from surveying free amino acid content of wild and cultured river puffer showed difference in content, but generally taurine and lysine content for the whole free amino acid held the most part. There was no significant difference in texture, flavor and overall acceptance score between the cultured and wild fishes (P>0.05).

• Korean Journal of Ecology and Environment
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• v.55 no.1
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• pp.49-59
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• 2022

Total of 325 estuaries in Korea were surveyed to analyze the effect of presence of sluice gate on the estuary environment and fish community from 2016 to 2018. Fish community in closed and open estuaries showed differences generally, and the relative abundance (RA) of primary freshwater species in the closed and migratory species in the open estuaries were high. The result of classifying species by habitat characteristics in closed and open estuaries showed similar tendencies at the estuaries of south sea and west sea. The relative abundances of primary freshwater species in the closed estuaries at the estuaries of south sea and west sea were the highest, but estuarine and migratory species were high in both closed and open estuaries at the estuaries of east sea. Primary freshwater species showed higher abundances in the closed estuaries with reduced salinity due to blocking of seawater since they are not resistant to salt. However, primary freshwater species in open estuaries at east sea was higher than that of the closed estuaries, which is considered to be the result of reflecting the characteristics (tide, sand bar, etc.) of the east sea. Korea Estuary Fish Assessment Index (KEFAI) was showed to be higher at open estuaries than closed in all sea areas (T-test, P<0.001), the highest KEFAI was observed in closed estuaries at south sea, and open estuaries in east sea. Fish community of closed and open estuaries in each sea areas showed statistically significant differences (PERMANOVA, East, Pseudo-F=3.0198, P=0.002; South, Pseudo-F=22.00, P=0.001; West, Pseudo-F=14.067, P=0.001). Fish assemblage similarity by sea areas showed a significant differences on fish community in closed and open estuaries at east sea, south sea, and west sea (SIMPER, Group dissimilarity, 85.85%, 88.36%, and 88.05%). This study provided information on the characteristics and distribution of fish community according to the types of estuaries. The results of this study can be used as a reference for establishing appropriate management plans according to the sea areas and type in the management and restoration of estuaries for future.

• Ocean Systems Engineering
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• v.7 no.4
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• pp.345-369
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• 2017

The ocean environment offshore West Africa is considered to be mild. However, the generated swell from distant North and South Atlantic during austral winter and summer can reach high wave amplitudes with relatively low wave periods or low wave amplitudes with long wave periods, the later can be a crucial scenario to consider when the assessment of vessel resonance is of importance. Most offshore operations, which include offshore drilling, and installation in West Africa, are carried out from floating systems. The response of these systems and performance are governed by characteristics, such as amplitude and frequency of the wave and swell seas. It is therefore important to fully understand the sea conditions offshore Nigeria. This study covers the description of the swell sea offshore Nigeria using Bonga offshore wave measurements collected from the directional wave-rider (DWR), positioned at the Bonga site off the coast of Nigeria.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.6
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• pp.276-280
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• 2001

This paper presents the result of a study on the distribution characteristics of salt contaminants in the west coast region, from Inchon to Yearsoo, of South Korea. To evaluate the distribution characteristics of salt contaminants, we had measured the equivalent salt deposit density(ESDD) with brush wiping method for thirteen month(from May 1999 to June 2000). Under the consideration on the measuring interval and method, normalization method was applied for the ESDD data. Besides the measurement, the chemical analysis (chromatography) was carried to investigate the relationship, between the electrical property and the amount of specific ingredient, such as sodium, magnesium and chloride. From the result, we could get the representative value of contamination for each site and distribution characteristics of salt contaminants with the distance from sea in the west coast.