• Ocean Science Journal
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• 제41권4호
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• pp.301-313
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• 2006

Abundance and distribution of phytoplankton in seawater at southwestern East/Japan Sea near Gampo were investigated by HPLC analysis of photosynthetic pigments during summer of 1999. Detected photosynthetic pigments were chlorophyll a, b, $c_{1+2}$ (Chl a, Chl b, Chl $c_{1+2}$), fucoxanthin (Fuco), prasinoxanthin (Pras), zeaxanthin (Zea), 19'-butanoyloxyfucoxanthin (But-fuco) and beta-carotene (B-Car). Major carotenoid was fucoxanthin (bacillariophyte) and minor carotenoids were Pras (prasinophyte), Zea (cyanophyte) and But-fuco (chrysophyte). Chl a concentrations were in the range of $0.16-8.3\;{\mu}g/land$ subsurface chlorophyll maxima were observed at 0-10m at inshore and 30-50 m at offshore. Thermocline and nutricline tilted to the offshore direction showed a mild upwelling condition. Results from size-fraction showed that contribution from nano+picoplankton at Chl a maximum layer was increased from 18% at inshore to 69% at offshore on average. The maximum contribution from nano+picoplankton was found as 87% at St. E4. It was noteworthy that contribution from nano+picoplanktonic crysophytes and green algae to total biomass of phytoplankton was significant at offshore. Satellite images of sea surface temperature indicated that an extensive area of the East/Japan Sea showed lower temperature ($<18\;^{\circ}C$) but the enhanced Chi a patch was confined to a narrow coastal region in summer, 1999. Exceptionally high flux of low saline water from the Korea/Tsushima Strait seemed to make upwelling weak in summer of 1999 in the study area. Results of comparisons among Chi a from SeaWiFS, HPLC and fluorometric analysis showed that presence of Chi b cause underestimation of Chi a about 30% by fluorometric analysis but overestimation by satellite data about 30-75% compared to HPLC data.

• 수산해양기술연구
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• 제36권1호
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• pp.25-32
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• 2000

A combination steering system was designed to provide the flexibility in controlling the steering wheel in fishing operations of the inshore and coastal fishing vessels. The designed steering system basically is consisted of three driving units, such as a electrically driven hydraulic pump unit with a solenoid control valve, a DC motor driven hydraulic pump unit and a manually driven hydraulic pump unit, and two controllers to provide remote steering on the deck, respectively. The steering torque was measured and analyzed to investigate the dynamic performance of the developed steering system. The steering system showed excellent linearity between the working pressure of cylinder and the torque of rudder post in case of increasing in rudder angle from $5^{\circ} to 35^{\circ}$ that is, the steering torque increased from $10.4 kgf{\cdot}m$ to $105.3 kgf{\cdot}m$ and then the working pressure of cylinder fluctuated from 6.3 kgf/cm super(2) to 16.4 kgf/cm super(2). The steering time of 3.2 sec in remote hydraulic steering by the on/off solenoid valve control was much faster than 13.2 sec in the manual steering by the helmsman and 11.6 sec in the electric steering by a DC motor, and then it was verified that operation of one unit does not affect other units in combination steering system in any way. Furthermore, the developed steering system can be remotely controlled in multiple stations of the deck during the fishing operation and the automatic pilot steering unit can be used to add hydraulic steering.

• Ocean and Polar Research
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• 제45권2호
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• pp.43-55
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• 2023

This study was conducted to understand the seasonal patterns and variation of the copepod community in the Anma Islands of Yeonggwang, Yellow Sea, with a focus on seasonal surveys to assess the factors affecting their occurrence. Throughout the survey period, Acartia hongi, Paracalanus parvus s. l., and Ditrichocorycaeus affinis were dominant species, while Acartia ohtsukai, Acartia pacifica, Bestiolina coreana, Centropages abdominalis, Labidocera rotunda, Paracalanus sp., Tortanus derjugini, Tortanus forcipatus occurred differently by season and station. As a results of cluster analysis, the copepod communities were distinguished into three distinct groups: spring-winter, summer, and autumn. The results of this study showed that the occurrence patterns of copepod species can vary depending on environmental conditions (topographic, distance from the inshore, etc.), and their spatial occurrence patterns between seasons were controlled by water temperature and prey conditions. One of the physical mechanisms that can affect the distribution of zooplankton in the Yellow Sea is the behavior of the Yellow Sea Bottom Cold Water (YSBCW), which shows remarkable seasonal fluctuations. More detailed further studies are needed for clear grounds for mainly why to many Calanus sinicus in the central region of the Yellow Sea are seasonally moving to the inshore, what strategies to seasonally maintain the population, and support the possibilities of complex factors.

• 한국해양학회지
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• 제18권1호
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• pp.55-63
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• 1983

韓國 沿岸의 定期觀測所 41個所中 各海域別로 內灣側과 外海側 各各 1個所 씩 6個所를 選定 (東海 ; 浦港, 鬱陵島, 南海 ; 濾水, 馬羅島, 西海 ; 馬山, 小靑島) 하여 表面水溫과 氣溫의 旬別累年平均(16-51개년 ; 1923-1979)을 使用하여 Schuster法의 週期分析과 同時에 1個月前의 氣溫과 現在의 水溫과의 相關分析을 最小自乘法에 의한 2次相關式으로 考察한 缺課를 要約하면 다음과 같다. 1) 週期分析 가)年較差는 表面水溫이 外海側 12.77-17.99$^{\circ}C$(計算値 ; 11.67-16.64$^{\circ}C$), 內灣側 15.72-26.33$^{\circ}C$(計算値 ; 15.13-25.29$^{\circ}C$)였고, 氣溫은 外海側과 內灣側 區別 없이 21.71-28.6$0^{\circ}C$(計算値 ; 20.50-27.22$^{\circ}C$)였다. 나)年平均은 表面水溫이 11.25-18.78$^{\circ}C$로 外海側이 內灣側보다 高溫이었고, 氣溫은 11.39-16.16$^{\circ}C$로 緯度가 增加할수록 低溫을 보이고 있다. 다)年週期成分의 振幅은 水溫이 5.72-12.54$^{\circ}C$ 氣溫이 10.04-13.49$^{\circ}C$로서 각각 馬山이 最大, 馬羅島가 最小였다. 라)半年週期成分의 振幅은 水溫이 0.83-1.3$0^{\circ}C$, 氣溫이 0.72-1.26$^{\circ}C$로 外海側은 水溫이, 內灣側은 氣溫이 각각 컸다. 마)年週期成分의 位相은 水溫의 內灣側이 215-228 (極大 ; 8月 上-中旬), 外海側 이 238-244 (極大 ; 8月 下旬)였으며, 氣溫은 212-220 (極大 ; 7月 下旬-8月 上旬)였다. 바)半年週期成分의 位相은 水溫의 外海側이 87-110 로 極大期가 빨라지고, 內灣側은 167-212 로 水溫의 156-189 와 같이 極大期가 늦어진다. 2) 相關分析 가)水溫上昇期의 2次常數는 外海側이 0.010-0.026으로 증형이나, 內灣側은 -0.020-0.001로 漸減형 또는 比例型이었다. 나)水溫下落期의 2次常數는 0.012-0.021로 모두 漸增형이었다. 다)決定係數는 水溫上昇期가 r/sop 2/=0.964-0.992, 水溫下落期가 r$^{2}$=0.982-0.999로서 韓國 沿岸의 表面水溫은 1個月前의 氣溫으로 豫測이 可能하다고 推定된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.553-555
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• 2004

In this paper, high performance radio buoy system used for inshore and deep sea fishery is developed and experimented. Location of radio buoy can be accurately monitored and traced by the mother ship using GPS technology, and optimum access protocol is adopted to minimize the power consumption of radio buoy system. Developed system can cover over 80Km coastal range with 8 W transmitting power and -115 dBm receiver sensitivity and can ensure high security from burglary and loss using digital coding technology.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 학술대회 논문집 정보 및 제어부문
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• pp.550-552
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• 2004

In this paper, access protocol is proposed that can optimally control the radio buoy system used for inshore and deep sea fishery. Proposed protocol can minimize the power consumption of radio buoy and can ensure high security from burglary and loss, and it enable a mother ship to control remotely more than 150 radio buoys simultaneously. GPS technology and remote control techniques are used to monitor the exact location and status of the radio buoy system in real time.

• 수산경영론집
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• 제43권3호
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• pp.59-73
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• 2012

This study has the purpose to examine the effects of hygiene factor(job environment factor) and motivation factor(job motivation factor) of seamen on satisfaction, turnover intention and organizational commitment. To that end, with the scope of study subjects limited to coastal waters seamen, positive analysis was done through literature study and questionnaire analysis, and focus was given to the prospect of acquiring seamen by change of outside environment. Results of analyzing the factors affecting coastal waters seamen satisfaction, turnover intention and organizational commitment were as follows. First, the factors that affect satisfaction significantly are personal relationship and willingness to participate. Second, the factor that affects turnover intention significantly is employment stability. Third, the factors that affect organizational commitment significantly are personal relationship and willingness to participate.

• 수산해양교육연구
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• 제18권1호
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• pp.31-38
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• 2006

Reaseach efforts regarding the handicap system for the fair determination of the ranking of yacht racing for various sizes have started in the end of 19th century led by Europe and America.The development of the handicap system started in 1952 as inshore and offshore races began. A simple empirical handicap system has been selected by IOR and IMS rule in mid 70's, and more advanced technique based on theoretical and computer simulation has been selected in late 70's by IMS rule. While each techniques have relative merits, it is found that the simple empirical handicap system is more effective than the advanced technique in term of reliability and easiness of use as more racing records are accumulated.

• Journal of the korean society of oceanography
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• 제33권1-2호
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• pp.28-34
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• 1998

Variations in abundance, size and population structure of Calanus sinicus were studied in the southern waters of Korea in connection with hydrographic conditions during 1991-1992. Abundance was high in April and low in August. This species was concentrated inshore of a coastal temperature front, or around the temperature front in April. The 1st-3rd copepodites dominated in February and April, and adults in August. The mean population stages in February and April were younger than those in other survey months. This suggests that this species mainly reproduced during winter-early spring. In prosome length, the 1st-4th copepodites were larger in April than in other survey months, and the 5th copepodite and adult were the largest in February. Mean prosome length of C. sinicus showed weak inverse relationship with sea water temperature, but it was not statistically evidenced.

• Animal Systematics, Evolution and Diversity
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• 제30권3호
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• pp.206-214
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• 2014

Two monstrilloid copepod species belonging to the genus Monstrilla Dana are newly recorded from Korea: M. grandis Giesbrecht, 1891 and M. hamatapex Grygier and Ohtsuka, 1995. Specimens were obtained from inshore waters around the coasts of South Korea, using a light trap installed at quays and wharves overnight. Based on the Korean specimens, the two species are redescribed, with brief accounts of their affinities and morphological variabilities. Remarkable morphological discrepancies are confirmed in female leg 5 of M. grandis between type material from Southern Hemisphere and European and Asian specimens, which raise a strong doubt on their conspecificity. Korean specimens of M. hamatapex well coincide with the type specimens from Japan, except for some variations in the setal armature of leg 5 and antennules. This is the second taxonomic paper on the monstrilloid copepods in Korea, and the genus Monstrilla is newly added to Korean fauna.