• 제목/요약/키워드: By-catch

검색결과 995건 처리시간 0.023초

트랙터용 프론트 로더의 충격해석에 관한 연구 (Study on the Impact Analysis of Front Loader for Tractor)

  • 임기수;이부윤
    • 한국산학기술학회논문지
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    • 제16권8호
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    • pp.5051-5059
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    • 2015
  • 농업용 트랙터 프론트 로더의 낙하정지시험, 코너당김시험, 코너충돌시험의 세 가지 충격시험 조건에 대하여 강체동해석, 과도구조해석, 정적구조해석 등을 수행하여 각 부품의 응력분포를 구하고 안전성을 평가하였다. 낙하정지시험은 프론트 로더를 최대높이에서 시작하여 세 단계로 나누어 낙하시킨 후 정지시켜서 충격을 가하는 경우를 해석하였다. 코너당김시험은 체인으로 버켓 밑면의 모서리를 지면에 구속한 상태에서 프론트 로더를 갑자기 상승시키는 경우를 해석하였다. 코너충돌시험은 주행 중에 버켓의 모서리가 충격장애물과 충돌하는 경우를 해석하였다. 세 가지 충격시험 조건에 대한 해석 결과, 모두 마운트의 사각관 모서리와 마운트의 양쪽 꺾임 위치에서 국부적 응력집중이 발생하였다. 이러한 결과를 바탕으로 새로운 프론트 로더의 설계 및 수정 시 파단에 관한 안전성을 개선하는데 도움이 될 것으로 기대된다.

새우조망 어구의 막대 (빔)와 날개그물 길이에 따른 어획성능과 양망 작업에의 영향 (Catching efficiency of a shrimp beam trawl according to the length of beam and wing net and its influence on the hauling work)

  • 박해훈
    • 수산해양기술연구
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    • 제50권3호
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    • pp.396-406
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    • 2014
  • Shrimp beam trawl fishery is one of the important coastal fisheries in Korea. It has a regulation to the length of beam (8m) and wing net (7m) of shrimp beam trawl that has been used in the district of Junlanam-do and Gyungsangnam-do. This regulation was made in relation to the size of shrimp beam trawler of 3-ton class at that time. Now the shrimp beam fishing vessel has a limit not greater than 5 tons in gross ton. Recently, with improvement of fishing industry and fishing vessel fishermen asked the expansion of the length of beam and wing net, therefore it is necessary to investigate the effect of lengthening the beam and wing net length. Three different beams (8m, 10m and 12m in length) and three different wing net (7m, 10m and 13m in length) were made and the experiment was conducted near Narodo of Goheng by two fishing vessels of 4.98 and 4.88 tons in gross ton between June 2011 and October 2012. When the length of wing net was increased from 7m to 10m and 13m, the relative catch ratio in total biomass was increased 25% and 79% for shrimp, (17% and 22% in total), respectively. And when the beam length was increased from 8m to 10m and 12m, the relative catch ratio was increased 35% and 84% for shrimp, (21% and 37% in total), respectively. The force exerted to the iron guide of inhauler's with the beam length of 8m was about 30% greater than that with the beam length of 10m when hauling the shrimp beam trawl net.

대서양 한-가나 합작법인 소속 다랑어 선망어선의 조업실태 분석 (Analysis on the fishing conditions of tuna purse seiner belonging to the Korea-Ghana joint venture in the Atlantic Ocean)

  • 권기준;이춘우;김형석;류경진;이유원
    • 수산해양기술연구
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    • 제57권3호
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    • pp.194-204
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    • 2021
  • The research was analyzed the catch data of the five years (2016-2020) for six joint venture company tuna purse seiners in the Atlantic Ocean, with the aim of suggesting improvement measures for responsible and sustainable fishing according to changes of recommendation by International Commission for the Conservation of Atlantic Tuna (ICCAT) on the tropical tunas. In the last five years, the average catch of six tuna purse seiner gradually increased to 7,745 tons, 8,364 tons and 9,053 tons from 2016 to 2018, but decreased to 7,761 tons in 2019 and 6,214 tons in 2020. The reason for the decrease in fishing volume in 2019 and 2020 was the fluctuation of the formation of the cold water zone (22-23℃), and the total ICCAT convention area of FAD closure in January and February due to the expansion of the FAD closure area and poor free school catching during two months period, respectively. The analysis on fishing area showed that the percentage of fishing in the high sea was about 85% although the FAD closure area included the EEZ zone in coastal countries; the rise of the fishing license in coastal countries is also believed to be a factor. In order to overcome such situations and improve catching volume, it will be possible if excellent manpower is secured, school fishing is expanded, and the production of high value-added catch (purse seine special: PS).

Development and Evaluation of the V-Catch Vision System

  • Kim, Dong Keun;Cho, Yongjoo;Park, Kyoung Shin
    • 한국컴퓨터정보학회논문지
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    • 제27권3호
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    • pp.45-52
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    • 2022
  • 체감형 스포츠 게임은 센서나 카메라를 이용하여 사용자의 신체 움직임을 추적하고 현실감을 느끼게 하는 운동 게임이다. 최근 체감형 스포츠 게임을 학교 체육활동에 사용하기 위해 가상현실 실내 스포츠룸 시스템을 설치하고 있다. 그러나 이러한 시스템은 주로 화면 터치 사용자 상호작용을 사용한다. 본 연구에서는 2차원 벽 터치 인터랙션이 아닌 3차원 공간에서 사용자의 움직임을 추적할 수 있도록 AI 이미지 인식 기술을 사용하는 브이캐치 비전 시스템을 개발했다. 그리고 본 시스템의 운동 효과를 알아보기 위하여 사용성 평가 실험을 진행했다. 실험에서 피험자에게 혈중 산소 포화도와 실시간 심박변이와 키넥트 골격 이동량, 각도 변화량을 측정하여 정량적 운동 효과를 살펴보았다. 실험 결과 브이캐치 비젼 시스템 사용 시 통계적으로 유의미한 심박수 증가와 신체 움직임양 증가로 운동 효과가 있었던 것으로 나타났다. 실험후 설문조사 주관적 평가 결과에서 대부분의 피실험자들은 이 시스템을 사용한 운동이 재미있고 만족스러워했다.

중국 어선의 북한 동해수역 입어동향과 대응방향 (A Study on the Status of Chinese Fishing in the East Sea off North Korea and Directions for Countermeasures)

  • 이정삼;류정곤;기해경
    • 수산경영론집
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    • 제48권3호
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    • pp.61-74
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    • 2017
  • This study is aimed to analyze the change of chinese fishing vessels' entry into the East Sea off North Korea and suggest directions for countermeasures. Based on the real landing data in China, Chinese fishing vessels' squid catch volume and value in the East Sea off North Korea are estimated. Results show that at least 205 thousand tons of squid was caught by Chinese fishing vessels in 2014. If the catch amount is calculated by the unit price per kilogram at the same year in Korea, it would be 556.3 billion KRW. As the UN sanctions become stricter with the recent resolution 2371 passed, Chinese fishing vessels' entry may increase in the future to compensate decreased seafood supply from North Korea. Even though there are not many options left for Korea to decrease the impact of Chinese depletive fishing, the study suggests countermeasures such as strengthening cooperative crack down on the Chinese illegal fishing vessels in Korean waters; increasing cooperation with UN member countries to incorporate banning the trade of fishing rights in the next UN sanctions; establishing regional fisheries management organization and managing migratory species with China and Japan cooperatively in the long term.

A Study on the Retina shaped Optical Path Shift Using the Prism

  • Kwon Yun Jung;Nam Sang Yep;Lee Sung Chang
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2004년도 학술대회지
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    • pp.699-702
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    • 2004
  • This paper discusses about the mechanism of catching an image through an optical manipulation of each organizations in the eye, more specifically, mechanism of catching an image on a retina through a Camera and a Crystal Lens. In the retina, the macula roles as a fovea contrails and it leads the image which is about 3 mm to be shaped on there. However, even the macula may not properly function, our eyes still can catch the image by shifting the optical path to around of the macula, even if the sensitivity of the image is generally lower than the image on the macula. This paper proposes a method of shifting the shaped image on the retina by refracting the optical path through a prism located on the rear of a screen which consists of a 0.7' TFT LCD. Applying this method that throwing an image around on the macula, central visual disturbance patients among retinitis pimentos patients can expect to recover such a mechanism to catch an image.

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우리나라 동해안 북형 통발에 대한 물레고둥(Buccinum striatissimum)의 망목 선택성에 관한 연구 (Study on the mesh selectivity of a drum shaped pot for finely-striate buccinum (Buccinum striatissimum) in the eastern coastal waters of Korea)

  • 김성훈;정성재;박창두;김병관
    • 수산해양기술연구
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    • 제56권3호
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    • pp.193-201
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    • 2020
  • The mesh selectivity of a drum shaped pot for finely-striate buccinum (Buccinum striatissimum) was conducted a total of eight times with four different mesh sizes (22, 35, 50 and 60 mm) from May to September, 2019 in the eastern coastal waters of Korea. The size selectivity analysis was estimated by the SELECT method to express logistic selectivity curves. In the results, the catch of finely-striate buccinum was occupied about 90% in the total catch weight. The equation of the master curve of selectivity was estimated to s(R) = exp(-7.778R+9.983)/[1+exp(-7.778R+9.983)]. The relative shell height of 50% selection was 1.284 and the selection range (SR) was 0.282. The optimal mesh size for 50% selection on the minimum maturation size (75 mm, Shell height) was estimated more than 60 mm by the master selectivity curve.

문어흘림낚시용 친환경 봇돌의 색 효과 (Color effect of the environment-friendly sinker for octopus drift-line)

  • 안영일
    • 수산해양기술연구
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    • 제45권3호
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    • pp.144-150
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    • 2009
  • The choice behavior of the octopus in response to the environment-friendly colored sinker for octopus driftline and the sinker's fishing effect were studied under experimental conditions in the water tank and the field. The colors of the sinkers used for the experiment are white, black, yellow and green. Artificial baits are attached to the sinkers in order to attract the octopuses in the experiment. In the water tank experiment, two sinkers of two different colors are placed in a compartmentalized corner of the rectangular tank, and a CCD camera records the choice behaviors of the octopuses to the colored sinkers. In the field experiment, the catch investigation of octopus for each colored sinker was conducted 14 times in total by using 2(A, B) commercial fishing boats at the coast of Gangneung within 30m of depth in 2006. The number of colored sinkers per operation was a total of 24-40 pieces with the same number of sinkers individually for four colors. As a result, it was found that the octopus selected white the most followed by black and yellow in their choice of colored sinkers in the water tank experiment, and green was the lowest in their choice. Even in the field experiment, the sinkers of white and black showed a higher catch of octopus than the sinkers of yellow and green.

한국 근해 쌍끌이 대형기선저인망어선의 규모별 효율성과 어회능력 활용도 평가 (Scale Efficiency and Fishing Capacity Analysis for Large Pair-Trawl Vessels in Korean Waters)

  • 이동우;이재봉;정석근;김영혜
    • 한국수산과학회지
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    • 제41권6호
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    • pp.485-492
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    • 2008
  • To propose proper vessel characteristics for sustainable fisheries in Korean waters, we analyzed the fishing capacity, scale efficiency and utilization of large pair-trawl vessels based on the database of catch, effort and vessel characteristics (gross tonnage and engine power) in 1990 by applying data envelopment analysis (DEA). The input factors were gross tonnage, horse power and days operated; whereas the output factor was expected catch by vessel characteristics. The optimal vessel types, selected based on the input-oriented technical efficiency and gross tonnages, was 100 GT with engine power <600 HP. The output-oriented unbiased estimate of capacity utilization (CD) decreased with increasing vessel tonnage. For the same tonnage vessels, the CD decreased with increasing engine power.

한·중 공동수역에서 저층트롤 어획물의 조성 (Distribution Characteristics Composition of Fishes by a Bottom Trawl in the Jointly Controlled Waters of the East China Sea)

  • 김민석;김동수;김민선;이종근;김종화;강일권
    • 수산해양교육연구
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    • 제23권2호
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    • pp.141-152
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    • 2011
  • This study was investigated the species composition of demersal fishes by a bottom trawler GAYA, in order to be used basic data for resources management of fishery in the jointly controlled waters of the West sea. We caught 39 species, 5,532 individuals and 322.518kg in biomass. The number of species was the fewest of the jointly controlled waters of the East china sea and boundary zone between Busan and Tsushima. The first dominant species in individuals in summer was Oregonia gracilis, and in biomass was angler. But angler was the first dominant species in 7 stations of 12 stations. It was a peculiar phenomenon that cod which lives in a cold current was caught in the northern part of the West sea. In this connection it seems to be needs for oceanographic research. Catch per unit effort (kg/hr) of bottom trawl was the higher in northern part and in right line of all surveyed area respectively.