• Title/Summary/Keyword: gears

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Ecosystem-based resource assessment on coastal fisheries of Uljin in East Sea of Korea (한국 동해 울진 연안어업의 생태계 기반 자원평가)

  • Yoon, Sang-Chul;Zhang, Chang-Ik;Seo, Young-Il;Kim, Zang-Geun
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.50 no.4
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    • pp.567-582
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    • 2014

  • Coastal fisheries in Korean waters have highly complexity with a variety of fishing gears, and scale of those fisheries is smaller than that of offshore fisheries. As a result, important spawning and nursery grounds for many species of fish has been destroyed. The pragmatic ecosystem-based approach was developed for the assessment of fisheries resources in Korean waters by Zhang et al. (2009; 2010). As for the species risk index (SRI), common squid caught by coastal gillnet in the Uljin region had the highest risk. As for the fisheries risk index (FRI), coastal gillnet in the Uljin coastal waters had the highest risk. For the common squid which had the highest SRI, resources management strategies must be established such as catch prohibition of length and period with TAC. For the coastal gillnet in the Uljin region which had the highest FRI, it is judged to need management plans for conserving biodiversity as reducing the catch of non-target species and discards. Also to protect existing habitat, illegal fishery should be prohibited, and fishing gears should be designed in the environmental-friendly way considering when fishing gears lost.

  • https://doi.org/10.3796/KSFT.2014.50.4.567 인용 PDF KSCI

Research on the technical development by the CAD/CAM System (CAD/CAM시스템을 이용한 기술개발에 대한 연구 (워엄기어 개발을 중심으로))

  • Jeong, Seon-Mo
    • Journal of the Korean Society for Precision Engineering
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    • v.3 no.3
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    • pp.40-71
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    • 1986

  • By developing a computer program for the systematic design of worm gears, the design formulae and tables of AGMA, JGMA, BS and DIN are analized and compared. The computer program can be used on micro-computers. According to the input data of the reduction ratio, the center distance. the driving torque and the material as design parameters, the program calculate the most efficient worm gear dimension. The variation of the design parameters and other empirical coefficients in case of resulting an inadequate design gear dimension can be easily modified throuth the way of interactive method between the user and the monitoring system of computer. A proposal of the standardization of worm gears was made in which a standard module according to the DIN 323 standard series number was applied. For the more exact and effective calculation of the stress concentration and the deformation of gear teeth, a computer program using the boundary element method is also developed. Even the strength of the special gear shape such as Niemann's "Cavex" gear can be calculated in a short CPU-time. The most effort of this study has been layed on the developing a computer program for the correction of a tooth profile and face width which is most important design factor for an exact and wide teeth contacts under loads, especially by great and wide gears. For this purpose were investigated the tooth stiffness, the mesh interferences and the kinematics and the dynamics of gear mesh. The deflection and the deformation of the gear shaft due to the loads acting on gear and shaft were aslo considered. Some examples have shown the sufficient good status of teeth contact in which the correction of the tooth profile and face width were accomplished due to the calculated results.d results.

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Relative efficiency and mesh selectivity of monofilament and twisted multifilament nylon gill net for Pacific saury, Cololabis saira, in the Northwest Pacific Ocean (북서태평양 꽁치 자망의 망지 재료에 따른 어획성능 및 망목선택성)

  • Jo, Hyun-Su;An, Doo-Hae;Koh, Jeong-Rack;Kim, Yeong-Seung;Park, Chang-Doo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.42 no.4
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    • pp.195-202
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    • 2006

  • To determine the relative efficiency and mesh selectivity of gill net for the Pacific saury, Cololabis saira, a series of fishing experiments was carried out in the Northwest Pacific Ocean from August 13 to October 13 in 2002, using gill nets of different mesh size(30, 33, 35, 37, 39 and 42mm) constructed from two kinds of twine material(monofilament, twisted multifilament nylon web). The relative efficiency of two material gears was expressed as the ratio obtained by dividing monofilament catch by multifilament catch in number. The master selection curve of each material gear was estimated by applying the extended Kitahara's method. The catch of experimental gears is mostly Pacific saury(98.6%), Cololabis saira. The kinds of bycatch are common squid(0.7%), Pacific mackerel(0.6%), etc. Catch comparisons in the two gears showed that monofilament nylon nets are 1.7 times more efficient. The optimum values in monofilament and multifilament gill net for Pacific saury are 8.28 and 8.23, respectively.

  • https://doi.org/10.3796/KSFT.2006.42.4.195 인용 PDF KSCI