• 수산해양기술연구
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• 제53권3호
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• pp.211-218
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• 2017

The catch performance of the silver-white jig for automatic jigging machine, developed to improve the effectiveness of LED fishing lamp in catching squid, was compared to that of the conventional green jig. The vessels used in this investigation were Haesong-ho (A-vessel), a training vessel of Gangwon State University and Haengbok-ho (B-vessel), a commercial fishing boat. In the case of the A-vessel, five to eight automatic jigging machines were used in the fishing operation with a 31.3 kW LED fishing lamp in summer. As for the B-vessel, fourteen automatic jigging machines were used with a 43.2 kW LED fishing lamp in autumn and winter. The results showed that the catch performance of the silver-white jig was similar to that of the green jig in the case of the A-vessel (p>0.05). However, in the case of the B-vessel, the catch performance of the silver-white jig was superior to that of the green jig in both winter (p<0.05) and autumn (P<0.001). Based on the catch performance results regarding the B-vessel in autumn, it is expected that the annual income increase that can be earned by using the silver-white jig will be KRW 26,385,000.

• 기술혁신연구
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• 제24권2호
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• pp.21-56
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• 2016

그간 우리나라 등 후발주자의 추격과 그 성과에 대해 다양한 연구가 수행되었으나, 후발주자가 개발한 제품의 아키텍처가 추격 성과에 미친 영향에 대한 논의는 극히 부족하였다. 또한 공작기계의 움직임을 자동으로 제어하는 핵심 부품인 수치제어장치 분야에서 우리나라는 반도체, 조선, 자동차 산업과 달리 과거 40년에 가까운 기간 동안 다양한 개발체제 운영과 정부 지원에도 불구하고 제한적인 추격 성과를 보이거나 추격에 실패하였다. 이에 따라 본 연구에서는 우리나라 공작기계 수치제어장치 개발 사례를 중심으로 제품 아키텍처가 추격 성과에 미친 영향을 탐색적으로 고찰하였으며, 이를 위해 동 분야의 후발주자임에도 불구하고 세계 선도 기업으로 성장한 일본 화낙의 수치제어장치 아키텍처 진화 사례에 대한 심층 분석을 병행하였다. 연구결과 일본 화낙은 1980년대 중반 이후 수치제어장치 아키텍처의 개방형 모듈화를 달성함으로써 다양한 공작기계 생산 기업의 요구 사항에 부응하면서 대량 생산을 통한 원가 절감이 가능한 수치제어장치를 개발 생산하는 데 성공하였다. 이를 통해 화낙은 시장 점유율 확대 및 뛰어난 성과를 달성하였음을 발견하였다. 반면 우리나라는 1970년대 말 이후 약 40년 간의 추격 노력에도 불구하고 수치제어장치 아키텍처의 개방형 모듈화를 달성하지 못함으로 인해 다양한 수요 기업이 생산하는 공작기계에 채택되는데 실패하였으며, 결과적으로 제한된 추격 성과에 그치고 말았다. 또한 이러한 제한적인 추격 성과는 개발 주체의 파산과 매각, 폐쇄 등으로 이어지면서 기술적 지식의 누적에 큰 어려움을 겪었으며, 이로 인해 수치제어장치 아키텍처의 개방형 모듈화를 달성할 수 있는 만큼의 기술을 축적하거나 설계 역량을 확보하지 못했음을 발견하였다. 본 연구 결과는 제품 아키텍처 관점에서 후발주자의 추격 성과를 규명하고, 성공적인 기술 추격에도 불구하고 시장추격에 실패하는 원인을 규명할 수 있는 이론적 기반을 구축하는 데 그 의의가 있다.

• 상하수도학회지
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• 제31권6호
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• pp.567-575
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• 2017

It is not cost effective to raise the density of catch basins in preparation for heavy rainfall in terms of construction and maintenance. Our researchers have developed the new catch basin for increasing interception capacity of runoff with internal filtration structure. To compare interception capacity of an existing catch basin with the invented catch basin, a hydraulic experiment device with 4% of road gradients and 0.2% of road gradients was constructed. For runoff conditions of 4.4 l/s, 6.7 l/s and 10.4 l/s, capability of runoff and separation capability of debris (sand and leaves) were evaluated. As the main experimental results, the effectiveness of the developed catch basin has been verified with an increase in interception rate of approximately 22% for the runoff of 6.7 l/s as heavy rainfall. However, the results of invented catch basin showed only 4.5% of settlement rate of debris regarding sand. Therefore, the authors proposed an improved tilted screen structure additionally. After reviewing the performance of improved catch basin, application of the invented catch basin is expected to drain runoff effectively when it is applied to the faulty road drainage section.

• 수산해양기술연구
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• 제51권1호
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• pp.42-49
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• 2015

According to the catch condition of Scomberomorus niphonius in autumn season affected greatly, the catch price for the set net fishery. Catch production and the selling price were relatively even except 2009 showing a great big blooming jellyfish of Nemopliema nomurai in 2008~2011. The fishing cost of the set net fishery in Yeosu has increased gradually by the decrease of catch production and unexpected environmental change like as jelly fish blooming. The increase of fishing cost diminished net income and caused a negative impact in profitability. The lowest Fisheries ratio of gross profit to gross costs the set net fishery were appeared 60.2% in 2010, respectively. Bycatch was highest in 2008 and lowest in 2009. In general, the bycatch was occurred from May to July every year and when Scomber japonicus was most dominant in the catch price by bycatch had a advantage in the profit side. However, the catch increase of immature small fishes by the bycatch, which will bring about the decrease of fisheries resources. Finally, the present state in set net fisheries will act as a defect on the long-term management of fisheries resources.

• 수산해양기술연구
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• 제48권1호
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• pp.72-81
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• 2012

Using artificial neural network (ANN) technique, auction prices for common mackerel were forecasted with the daily total sale and auction price data at the Busan Cooperative Fish Market before introducing Total Allowable Catch (TAC) system, when catch data had no limit in Korea. Virtual input data produced from actual data were used to improve the accuracy of prediction and the suitable neural network was induced for the prediction. We tested 35 networks to be retained 10, and found good performance network with regression ratio of 0.904 and determination coefficient of 0.695. There were significant variations between training and verification errors in this network. Ideally, it should require more training cases to avoid over-learning, which leads to improve performance and makes the results more reliable. And the precision of prediction was improved when environmental factors including physical and biological variables were added. This network for prediction of price and catch was considered to be applicable for other fishes.

• 한국수산과학회지
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• 제55권6호
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• pp.946-953
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• 2022

Using the management strategy evaluation methods and data on the Korea chub mackerel Scomber japonicus where the state-space logistic production model is used as the operation and the estimation model respectivley, we examined the effects of both Dorn's rule, α and the buffer value for ABC (allowable biological catch), which are used by the Korea fishery managers for decision rules. We set scenarios that have different pairs of buffer and α values, which include those currently used in the management in Korea. Under each sceanario, we projected the fish population biomass until year 2050, during which ABC is determined in each year with the decision rule. We used three kinds of performance measures: (i) whether the biomass in 2050 is overfished; (ii) the average of annual yields over the simulation period; and (iii) the variability of annual yields over the period. We found that the current practice (buffer=0.9, and α = 0.05) resulted in the best performance in terms of avoiding the "overfished" status. However, the current practice failed to reach the maximum average of the annual yields and led to larger uncertainty in the annual yields.

• 수산해양기술연구
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• 제58권2호
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• pp.95-105
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• 2022

In this study, the fishery status of the octopus pot fishery in the east coastal sea were investigated, and the fishing performance of each pot shape was compared and analyzed. The fishery status survey was conducted through listening surveys at Jukbyeon Port, Uljin Port and Pohang Daebo Port in Gyeongbuk Province, and the amount of fishing gear used, fishing method, size and loss of octopus pot fishery was investigated. On the east coastal sea, octopus is one of the commercially important fish stocks and is caught in inshore pots, inshore combos, inshore gillnets and offshore pots. Among these fishing methods, pot fishing yields the highest catch. The shape of the pot differs depending on the region. In Uljin (Jukbyeon Port and Hupo Port), Gyeongbuk, rectangular type net pots are mainly used, and in Pohang (Daebo Port) in Gyeongbuk, drum-type pots are mostly used. Enteroctopus dofleini accounts for more than 90% of the catch of octopus. For the octopus fishing performance test by trap type, three types of traps (rectangular pot, drum pot and cylinder pot) were used on the coastal sea of Pohang Daebo. As a result, the total catch by pot shape was shown in the order of rectangular-type pot > drum-type pot > cylinder-type pot. The catch of octopus, the target species, was in the following order: rectangular-type pot > drum-type pot > cylinder-type pot. Such result shows a significant difference (Mann-Whitney test, p<0.05).

• 수산해양기술연구
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• 제53권1호
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• pp.1-11
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• 2017

Fishing pots are one of the important fishing gears in our coastal and offshore fisheries. In terms of a sustainable use of marine resources, there are concerns about the ghost fishing by lost pots. It is reported that 10 to 70% of the pots are abandoned or lost annually. This study is to compare the catching efficiency of drum type whelk pots that are made of biodegradable nets to those made of the ordinary nets, in the eastern coast of Korea. Five types of drum pots were used with combination of biodegradable nets and ordinary (PA, PE) nets applied to the main and funnel parts of the pots: pots with biodegradable nets (Bio+Bio); pots with PE net (PE+PE); pots with body and funnel made of biodegradable nets and PE nets respectively (Bio+PE); pots with body and funnel made of PE nets and PA nets respectively (PE+PA); pots with body and funnel made of PE nets and biodegradable net respectively (PE+Bio). Field experiments were conducted from June $18^{th}$, 2015 to August $7^{th}$, 2015 using a commercial fishing vessel in the Uljin waters on the eastern coast of Korea. Two fleets of pots with one hundred in each, 20 pots of each type, were casted for 8 to 15 days to analyze their catching efficiency. The catch of target species, whelks, was 202,563.0 g with catch rate of 38.7% of the total catch, while the bycatch was 320,709.7 g with the rate of 61.3% of the total catch. The catch of whelks was the highest in the Bio+PE pots (46,020.3 g), followed by the Bio+Bio pots (42,027.5 g), the PE+Bio pots (41,849.9 g) and the lowest being PE+PE pots (38,054.2 g). Compared to the conventional pots, the pots with biodegradable nets on the body or entrance part had slightly higher catch rate for both the target species and the bycatch. The PE+PE had the lowest catch rate. There is no significant difference in catch between the pots with biodegradable nets and the ordinary nets for the target species such as Buccinum opisthoplectum, Neptunea eulimata, Buccinum striatissimum. Consequently, using biodegradable nets for the conventional whelk pots can reduce ghost fishing by lost gears while keeping the performance of the pots.

• 수산해양기술연구
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• 제30권1호
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• pp.1-12
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• 1994

Stow-net is originally spreaded with a lifting beam and a depressing beam. The net is improved by using canvas-made spreading devices by Mr. Han and his colleagues in the beginning of 1980's. The net is improved again by changing the partial shape of netting and arrangement of net pendants so as to be fitting with the actual performance of the net by Dr. Lee and his colleagues since 1988. The author studied to compare the fishing efficiency of those two kinds of nets(The former which was improve by Mr. Han is expressed as a traditional net and the latter improved again by Dr. Lee is expressed as an improved net in the present study). Twenty-one stow-netters concerned with the present study were selected among those based on the Port of Inchon, and were classified into two groups-eleven of them are a traditional net used group and ten are an improved net used group. The data on the fishing operation from August 1992 to March 1993, including the catch, the price of sell, the fishing operated times in every cruise and the fished position noticed by every stow-netter were offered by concerned stow-netters. From the data the times of operation, catch and value in every cruise were extracted and analyzed. The results obtained can be summarized as follows: 1. The times of operation in cruise were 13.7 by the traditional net used group and 12.7 by the improved net used group. 2. The mean catch per cruise showed 10.1M/T in the traditional net used group and 12.2M/T in the improved net used group, so the latter showed 21% better. 3. The mean catch per operation showed 0.7M/T in the traditional net used group and 0.9M/T in the improved net used group, so the latter showed 28% better. 4. The rate of three important species(starks, hair tail and croakers) in the total catch showed 83%, and the catch showed greater by the improved net used group at the rate of starks 141%, hair tail 110%, croakers 107%. 5. The rate of three important species in the total price showed 82%, but the price of starks which occupied the biggest in catch showed merely 5%, then the economical efficiency appeared low. 6. The mean price per stow-netter and per operation showed about 20%, greater respectively by the improved net used group and the mean price per operation by two important species(hair tail and croakers) showed greater about 30% by the improved net used group.

• Fisheries and Aquatic Sciences
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• 제13권2호
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• pp.182-189
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• 2010

An active stimulating device (ASD) using a rope apparatus may operated by the flow of turbulence inside a cod end, generating variable stimuli in addition to flow-related effects to minimize the by-catch of juvenile fishes. Preliminary testing involved a hydrodynamic effect inside the cod end with a rotating rope kite or conical rope array to generate variable stimuli (visual stimuli, water flow, or physical contact with fish) to change fish position. The experimental rope kite offered more choice in rotating period and range of sweeping action; adjusting the towing line or flow velocity helped to drive fish toward the net panel and encouraged escape. The conical shape of the rope array in the cod end helped to clear a path for fish by disturbing the rigging and providing more contrast between objects, preventing an optomotor response. This enabled more black porgy to be herded toward the net at an early stage of towing. Therefore, either a conical rope array or a rotating rope kite can be used as an effective ASD to prevent juvenile by-catch.