• 수산해양기술연구
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• 제54권3호
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• pp.224-230
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• 2018

Squid is one of the important fisheries resources in Korea. Therefore, squid has been designated and managed as a target species of total allowable catch (TAC) since 2007, but the catch amount is gradually decreasing. The analysis was conducted to identify the change of relative fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the offshore squid jigging fishery from 1960s to 2010s. Gross tonnage per fishing vessel increased with the increase in size until 1990, but then gradually decreased to 41.0 tons in 2000 and 37.1 tons in 2010. The illuminating power (energy consumption) by fishing lamps increased to 180 kW in 2005 and stabilized to 120 kW in 2015. Jigging machine started to be supplied to fishing vessels from the early 1970s, and fish finders began to be supplied in the early 1980s and gradually increased. Therefore, the relative fishing power index in the offshore squid jigging fishery increased from 1.0 in 1980 to 1.1 in 1990, to 3.5 in 2000 and to 2.5 in 2010, but the increment rate slowed down gradually. The results are expected to contribute to reasonable fisheries stock management.

• 수산해양기술연구
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• 제56권1호
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• pp.26-36
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• 2020

Thousands of pelagic and demersal fishes inhabit the waters around Korea and many of them are overexploited. One of the reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the otter trawl fishery from 1960s to 2010s. Gross tonnage was decreased stably, but horse power was increased annually. The perimeter of net mouth was somewhat longer, but little changed. Color fish finder was utilized from the mid-1960s. Hydraulic net drum were introduced in the early 1990s, and supply rate was gradually increased. Surveys on the supply and upgrading of fishing equipment utilized visiting research. Therefore, the relative fishing power index in the trawl fishery increased about two to three times in the 2010s compared to the 1980s. The results are expected to contribute to reasonable fisheries stock management.

• 수산해양기술연구
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• 제53권1호
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• pp.12-18
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• 2017

Lots of fishery stocks are overexploited and the overcapacity exists in Korean fishing fleets. One of the reasons is technological development, which increases the efficiency of the vessels continuously. The analysis was conducted to identify the change of fishing power index to develop the vessel and gear technology that may have improved the fishing efficiency of the offshore large powered purse seine fishery from 1960s to 2010s. Gross tonnage and horse power per fishing vessel was increased annually. Fishing gear material was changed to the knotless webbing to settle faster. Fishing equipments was modernized and supply rate was also increased. Therefore the relative fishing power index in the offshore large powered purse seine fishery increased from 0.4 in 1970 to 1.0 in 1980, to 1.5 in 2000 and to 1.6 in 2010, but the rate of increase slowed down gradually. The results are expected to contribute to reasonable fishery stock management.

• 한국태양에너지학회 논문집
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• 제35권5호
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• pp.11-19
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• 2015

In this paper, EP-Kalina cycle applying liquid-vapor ejector and motive pump is newly proposed. In this EP-Kalina cycle, the liquid-vapor ejector is used to increase pressure difference between inlet and outlet of the turbine. Also the motive pump enhances the performance of liquid-vapor ejector, resulting in increase of system efficiency of OTEC cycles. The comparison cycles in this study are basic, Kalina, EKalina and EP-Kalina ones. The pump work, net power, APRe, APRc, TPP and system efficiency of each cycle are compared. In case of net power, EP-Kalina cycle is lowest among the cycles due to the application of the motive pump. But, the net power difference of cycles seems to be minor since the pump work of cycles is merely about 1kW, compared to turbine gross power of 20kW. The system efficiency of EP-Kalina cycle shows 3.22%, relatively 44% higher than that of basic OTEC cycle. Therefore, the system efficiency is increased by applying the liquid-vapor ejector and the motive pump. Additional performance analysis is necessary to optimize the proposed EP-Kalina cycle.

• Journal of Biosystems Engineering
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• 제17권4호
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• pp.305-313
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• 1992

Stirling 기관(機關)의 피스톤 Seal부분에서의 마찰저항(摩擦抵抗)을 감소(減少)시킴과 동시 에 작동가스의 누설량(漏泄量)을 감소(減少)시켜서 기관출력(機關出力)을 증대(增大)시킬 목적(目的)으로 재질(材質) 및 밀봉(密封) 형식(形式)이 서로 다른 Piston ring식 밀봉기구(密封機構)와 금속(金屬) Bellows를 이용한 밀봉기구(密封機構)를 시작(試作)해서 마찰저항(摩擦抵抗)과 작동가스의 누설량(漏泄量)을 조사(調査)하고, 이들 밀봉기구(密封機構)를 실험(實驗) 기관(機關)에 장착(裝着)해서 운전시험(運轉試驗)을 통해 각 밀봉기구(密封機構)의 성능(性能)을 검토(檢討)하였다. 그 결과(結果) Bellows를 Power piston의 Actuator로 시작(試作)한 밀봉기구(密封機構)가 다른 Piston-ring식(式) 밀봉기구(密封機構)에 비(比)해, 피스톤링과 실린더벽 사이의 마찰저항(摩擦抵抗) 및 작동(作動)가스의 누설량(漏泄量)이 현저하게 감소(減少)하였으며, D-type은 B-type에 비해 도시출력(圖示出力)은 약 1.6배, 축출력(軸出力)은 약 1.2배로 증가(增加)하였다.

• 수산해양기술연구
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• 제25권2호
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• pp.61-69
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• 1989

한국 제주도와 대마도 주변해역을 중심으로 고등어와 정어리를 주어획대상으로 선단조업을 하고 있는 건착망어업의 어선의 성능, 어패의 크기, 어획성능, 조업해역별 단위노력당 어획량등을 조업어선의 톤급별로 분석, 검토한 결과는 다음과 같다. 1. 망선의 총톤수(x)와 건착망의 면적(y)간에는 y=538.8x+99657.3의 관계가 있었다. 2. CPUE의 계절변동지수는 11~4월은 기분보다 높고, 5~10월은 낮은 현상을 나타내었다. 3. 각 해역에 있어서 톤급별 어획성능지수는 톤급별, 해역별 CPUE는 1%의 유음수준에서 차가 인정되었다. 4. 톤급별 망어패의 효율은 A와 D급선 보다 B와 C급선이 높은 현상을 나타내었다

• 해양환경안전학회지
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• 제24권3호
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• pp.373-380
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• 2018

The small coastal vessel registered in Korea, small coastal vessels with a gross tonnage of 10 tons or less account for 94.6 % and among them, aged vessels over 16 years age indicate 40.6 %. In order to reduce GHG emissions from small coast vessels, discussions are underway to replace aging ships' propulsion units with eco - friendly propulsion facilities, and the electric propulsion ship is emerging as one of the measures. The electric propulsion system using the DFE rectifier, which was applied in the conventional large commercial vessel, was effective in reducing the harmonics and improving the DC output voltage of the DC link stage, but it occupied a large volume and caused an increase in the overall system price. Therefore, in this paper, we propose an electric propulsion system using AFE rectifier with a small volume of system that can be applied to a small coastal vessel. In order to analyze the effectiveness of the overall system, the load profile was applied to obtain accurate and rapid speed tracking performance of the propulsion motor affected by the speed load. In addition, the power factor and total harmonic distortion factor of the voltage and current on the improved power output side are derived through simulation.

• 전기학회논문지
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• 제62권10호
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• pp.1421-1424
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• 2013

The electronic equipment which is exposed to high level pulsed radiation is damaged by Upset, Latchup, and Burnout. Those damages come from the instantaneous photocurrent from electron-hole pairs generated in itself. Such damages appear as losses of a power in military weapon system or as a blackout in aerospace equipment and eventually caused in gross loss of national power. In this paper, we have implemented a RDC(Radiation detection and control module) as a part of the radiation protection technology of the electronic equipment or devices from the pulsed gamma radiation. The RDC, which is composed of pulsed gamma-ray detection sensor, signal processors, and pulse generator, is designed to protect the an important electronic circuits from the a pulse radiation. To verify the functionality of the RDC, LM118s, which had damaged by the pulse radiation, were tested. The test results showed that the test sample applied with the RDC was worked well in spite of the irradiation of a pulse radiation. Through the experiments we could confirm that the radiation protection technology implemented with the RDC had the functionality of radiation protection for the electronic devices.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 C
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• pp.1468-1471
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• 1999

This paper presents a method of the regional long-term distribution planning considering economic indicator with the assumption that energy demands proportionally increases with the economic indicators. For the practical distribution planning, it is necessary to regional load forecasting, distribution substation planning, distribution feeder planning. Accordingly, in this paper, after performing regional load forecasting considering economic indicator, it is performed distribution substation planning and distribution feeder planning in order by using this result. For accurate distribution planning, it is very important to scrutinize the correlation among the regional electric power demands, economic indicator and other characteristics because distribution planning results may vary depending on many different factors such as electric power demands, gross products, social trend and so on. In this paper, various steps microscopically and macro scopically are used for the regional long-term distribution planning in order to increase the accuracy and practical use of the results

• 한국수산과학회지
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• 제20권5호
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• pp.381-390
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• 1987

본 연구는 1985년 5월부터 1986년 5월까지 삼천포 화력발전소를 대상으로 발전소 냉각계통의 가동이 식물플랑크톤의 기초생산력에 미치는 영향을 구명하기 위하여 실시되었다. 발전소 냉각계통이 총기초생산력에 미치는 영향은 평균 $7.5\~58.9\%(4.6\~12.1mgC/m^3/h)$이었으며, 순기초생산력의 경우는 이보다 높은 수준이 $58.7\~83.5\%(8.4\~11.9mgC/m^3/h)$. 영향요인 중 가장 큰 요소는 냉각계통 통과시 입는 기계적인 영향으로 그 범위가 $21.1\~110.7\%$에 달하였다. 삼천포 화력발전소 냉각계통에 이한 식물성탄소에 해당하는 량으로 추계되었다.