• Title/Summary/Keyword: Net

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The Development of Midwater Trawl Net in North Pacific Ocean (북태평양(北太平洋) 중층(中層)트롤그물의 발달(發達))

  • Kwon, Byeong-Guk;Chang, Ho-Young
    • Journal of Fisheries and Marine Sciences Education
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    • v.6 no.1
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    • pp.11-19
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    • 1994
  • The North Pacific midwater trawling which is one of the important fishing methods for Korean fishing industry is working in the Bering Sea and the sea near Kamchaka Peninsula. The catch by Korean midwater trawlers had been recorded about 300 thousands $^{M/_T}$ a year. Six types of midwater trawl net-ordinary midwater trawl net, super-V trawl net, super mesh trawl net, rope trawl net, super plus trawl net and kite trawl net-have been widely used by large trawlers above 1,500gt in size since 1982. Regarding the fishing efficiency, the super plus trawl net and kite trawl net were acknowledged as higher than other nets. Maximum mesh size of super-plus trawl net and kite trawl net ranges about 20m, whereas the length of net about 150m, and high-tech polyethylene is used as the material of rope part. The problems involved in the North Pacific midwater trawl net may be summarized as follows ; (1) The dimension of fishing gear is too big compared with the towing power of trawler. (2) The mesh size of the rope part is too big compared with that of the common netting part. (3) The net is often torn out in the connecting position of the rope part and the netting part. (4) The net is not matched with the trawler and the otter board in many trawlers, so the shape of the trawl gear in the water is instable. (5) The fish school located near head rope, ground rope and side rope in the net recorder is not caught in practice because of the net instability.

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A Study of the Efficiency of the Labor-saving-type, Five-step-drum Net Hauler (생력형 5단 유자망 양망기의 효율성에 관한 연구)

  • Koo, Myung-Sung;Kim, Suk-Jong
    • Journal of Fisheries and Marine Sciences Education
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    • v.26 no.1
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    • pp.98-107
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    • 2014
  • As part of a series of studies about improving yellow croaker drift gill net fishing gear and the development of a labor-saving fishing system, we installed a labor-saving-type, five-step-drum net hauler, and a triple-V-type net hauler in 108 Daeheung-ho, a fishing boat which operates drift gill nets for yellow croakers mainly in the sea near Chu-ja Island. Net damage with the labor-saving-type, five-step-drum net hauler is lower than for the triple-V-type net hauler. In addition, there was a reduction in the standard operational crew of two people. The lead time for hauling the labor-saving net was approximately 10% and 19.2% less than for hauling the triple-V-type net hauler and for hauling by hand, respectively. It was found that there were fewer slip in fishing gear and less damage to the wing of the drum as well as less damage to the fish when the labor-saving-type, five-step-drum net hauler was used than when the triple-V-type net hauler was used. In the survey, the lead time for hauling the net was approximately 21.6% and 45.2% more effective than hauling with the triple-V-type net hauler and hauling by hand, respectively. The crew was reduced by approximately 18.2% and 25% than when hauling with the triple-V-type net hauler and hauling by hand, respectively. In addition, cessation of operation and damage to the fish were reduced when compared to the triple-V-type net hauler and hauling by hand.

Development of Novel Net Hauler for Improved Washing of Fishing Nets (어업용 그물 세척 효율 향상을 위한 그물 세척용 양망기 개발)

  • Choi, Deok-Ki;Kim, Yong-Young
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.34 no.11
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    • pp.1779-1784
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    • 2010
  • Net washing in a fishery involves considerable labor and is a time-consuming process; it also causes severe environmental pollution. In this study, we developed a net hauler for washing fishing nets. This hauler can be used to simultaneously haul and wash the net. We devised the revolver structure of the net hauler in order to resolve the net slip problem. The net hauler can be used by itself for washing small-sized nets, or it can be used in an auxiliary washing step in case of a large-sized net. Further, the component installed in the net hauler for unraveling the net improves the net washing performance of an automatic net washer. During the experiments conducted using the prototypes of the new net hauler, the net did not slip and the desired washing performance could be achieved.

The Spatial and temporal distributions of NET(Net Effective Temperature) with a Function of Temperature, Humidity and Wind Speed in Korea (한반도의 날씨 스트레스 지수 NET(Net Effective Temperature) 분포의 특성)

  • 허인혜;최영은;권원태
    • Journal of the Korean Geographical Society
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    • v.39 no.1
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    • pp.13-26
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    • 2004
  • This paper examined the possibility of NET application for a relative weather stress index in Korea. The characteristic of NET distribution used temperature, relative humidity, wind speed which forecasting at Korean Meteorological Administration were analyzed. Regional critical values of daily maximum NET of stress index for summer resembled the distribution of daily maximum temperature because were not impacted wind and humidity but temperature. Regional critical values of daily minimum NET of stress index for winter distributed variously compared with summer. The highland region and the northern region of Seoul were impacted of low temperature and coastal region which strong wind. The occurrences of stressful days did not vary in summer, but obviously increased in winter after mid-1990s.

Intermediate Language Translator for Jave Language (자바 언어를 위한 중간 언어 번역기)

  • 정지훈;박진기;이양선
    • Proceedings of the Korea Multimedia Society Conference
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    • 2003.11b
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    • pp.537-540
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    • 2003
  • 자바와 .NET 언어는 프로그래머들이 프로그램을 개발하는데 가장 널리 사용되고 있는 언어이다. 프로그래머가 작성한 자바 프로그램은 JVM 플랫폼에서는 실행이 되지만 .NET 플랫폼에서 실행이 되지 않고, 반대로 C#과 같은 .NET 언어로 작성한 프로그램은 .NET 플랫폼에서는 실행이 되지만 JVM 플랫폼에서 실행이 되지 않는다. 그러므로 자바 프로그래머는 .NET 플랫폼 환경에 맞추어 프로그래밍하지 못하고, .NET 프로그래머는 JVM 플랫폼 환경에 맞추어 프로그래밍하지 못하는 단점이 있다. 본 논문에서 연구한 Bytecode-to-MSIL 번역기는 위의 단점을 해결한 것이다. 먼저 자바로 작성된 프로그램을 컴파일하여 생성된 클래스 파일(*.class)로부터 Oolong 역어셈블러를 이용하여 Oolong 코드를 추출한다. 추출된 Oolong 코드를 본 논문에서 연구한 Bytecode-to-MSIL 번역기로 .NET의 중간언어인 MSIL 코드로 변환하여 .NET 어셈블러로 실행파일을 만들어 자바 언어로 구현된 프로그램이 .NET 환경에서도 실행될 수 있도록 한다. 따라서, 자바 프로그래머나 .NET 프로그래머는 JVM 이나 .NET 플랫폼 환경에 관계없이 프로그램을 작성하여 실행시킬 수 있다.

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A Study on Classification Performance Analysis of Convolutional Neural Network using Ensemble Learning Algorithm (앙상블 학습 알고리즘을 이용한 컨벌루션 신경망의 분류 성능 분석에 관한 연구)

  • Park, Sung-Wook;Kim, Jong-Chan;Kim, Do-Yeon
    • Journal of Korea Multimedia Society
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    • v.22 no.6
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    • pp.665-675
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    • 2019
  • In this paper, we compare and analyze the classification performance of deep learning algorithm Convolutional Neural Network(CNN) ac cording to ensemble generation and combining techniques. We used several CNN models(VGG16, VGG19, DenseNet121, DenseNet169, DenseNet201, ResNet18, ResNet34, ResNet50, ResNet101, ResNet152, GoogLeNet) to create 10 ensemble generation combinations and applied 6 combine techniques(average, weighted average, maximum, minimum, median, product) to the optimal combination. Experimental results, DenseNet169-VGG16-GoogLeNet combination in ensemble generation, and the product rule in ensemble combination showed the best performance. Based on this, it was concluded that ensemble in different models of high benchmarking scores is another way to get good results.

A Study on Slope Reinforcement Method for Control of Rockfall and Small Scale Failure (낙석 및 소규모 붕괴 방지를 위한 사면보강방안에 관한 연구)

  • Lee, Seung-Ho;Hwang, Young-Cheol;Noh, Heung-Jae;Sim, Seok-Rae
    • Proceedings of the Korean Geotechical Society Conference
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    • 2005.03a
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    • pp.796-805
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    • 2005
  • Most rockfall prevention net among the rockfall prevention equipment that is constructed in around the road is actuality lack of function by quantitative research insufficiency etc.. Most of rockfall prevention net are composed to setting needle, perpendicular and horizontal wire rope and wire net. Also, function of rockfall prevention net depend on setting needle and the wire net and perpendicular and horizontal wire rope are fixed by setting needle. when unreasonable load is offered setting needle, rockfall prevention net can lose the function and happen continuous falling off of rockfall prevention net. Because rockfall prevention net have a such structural defect, improvement had been required in reply. So in this paper, spot application of Rock Bolt & Net Connection method and falling rock support ability are estimated by numerical analysis. As a result, when Rock Bolt & Net Connection Method is applied to cutting slope, decreases of stress and displacement is examined than current rockfall prevention net.

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Cure Characteristics of Naphthalene Type Epoxy Resins for SEMC (Sheet Epoxy Molding Compound) for WLP (Wafer Level Package) Application (WLP(Wafer Level Package)적용을 위한 SEMC(Sheet Epoxy Molding Compounds)용 Naphthalene Type Epoxy 수지의 경화특성연구)

  • Kim, Whan Gun
    • Journal of the Semiconductor & Display Technology
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    • v.19 no.1
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    • pp.29-35
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    • 2020
  • The cure characteristics of three kinds of naphthalene type epoxy resins(NET-OH, NET-MA, NET-Epoxy) with a 2-methyl imidazole(2MI) catalyst were investigated for preparing sheet epoxy molding compound(SEMC) for wafer level package(WLP) applications, comparing with diglycidyl ether of bisphenol-A(DGEBA) and 1,6-naphthalenediol diglycidyl ether(NE-16) epoxy resin. The cure kinetics of these systems were analyzed by differential scanning calorimetry with an isothermal approach, and the kinetic parameters of all systems were reported in generalized kinetic equations with diffusion effects. The NET-OH epoxy resin represented an n-th order cure mechanism as like NE-16 and DGEBA epoxy resins, however, the NET-MA and NET-Epoxy resins showed an autocatalytic cure mechanism. The NET-OH and NET-Epoxy resins showed higher cure conversion rates than DGEBA and NE-16 epoxy resins, however, the lowest cure conversion rates can be seen in the NET-MA epoxy resin. Although the NETEpoxy and NET-MA epoxy resins represented higher cure reaction conversions comparing with DGEBA and NE-16 resins, the NET-OH showed the lowest cure reaction conversions. It can be figured out by kinetic parameter analysis that the lowest cure conversion rates of the NET-MA epoxy resin are caused by lower collision frequency factor, and the lowest cure reaction conversions of the NET-OH are due to the earlier network structures formation according to lowest critical cure conversion.

Expressions of Norepinephrine Transporter in Pre-eclamptic Placenta (자간전증 태반에서의 Norepinephrine Transporter(NET) 발현)

  • Na, Kyu-Hwan;Lee, Hyun-Jung;Jung, Ji-Eun;Kim, Gi-Jin
    • Development and Reproduction
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    • v.14 no.2
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    • pp.65-74
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    • 2010
  • Placenta has been shown to be a site of expression of several of the monoamine membrane uptake transporters. However, the correlation between the expressions of norepinephrine transporter (NET) and placental development including gynecological diseases is still unknown. To investigate the expression and functions of NET in placenta, we conducted to compare NET expression in normal and preeclamptic placenta and analyzed the function of NET in HTR8-SV/neo trophoblast cells after NET gene transfection. The expression of NET was analyzed in placental tissues from the following groups of patients (none underwent labor): 1) term normal placenta (n=15); 2) term with preeclamptic placeneta (n=15); and 3) pre-term with preeclamptic placenta (n=11) using semi-quantitative RT-PCR, immunohistochemistry, and Western blot. In order to evaluate the function of NET, NET gene plasmid and NET gene-specific siRNA were trnasfected into HTR-8/SVneo trophoblast cells for 24 hours. NET had low expression in the pre-eclamptic placenta compare with normal placenta but no difference in western blot data. NET was expressed in the trophoblasts, and the up-regulation of NET gene stimulated the invasion of HTR-8/SVneo trophoblast cells by 2.5 fold (p<0.05), whereas the NET-siRNA treatment reduced invasion rates. Also, we observed that the expression of NET induces to expression and activity of MMP-9 in HTR-8/SVneo trophoblast cells in zymography. The results suggest that the expression of NET were reduced in pre-eclampsia and should be inhibited invasion activity of trophoblasts. Therefore, these findings provide useful guidelines for the mechanisms of trophoblast invasion as well as for the basic understanding of gynecological diseases including pre-eclampsia.

The Opening Efficiency of Labor Saving net for the Anchovy Boat Seine (생력형 기선권현망 어구의 전개성능)

  • Jang, Choong-Sik;An, Young-Su;Kim, Koang-Hong
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.41 no.1
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    • pp.9-16
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    • 2005
  • This study was conducted in order to improvement of fishing gear and fishing operating system for anchovy boat seine by labor saving improved nets. Field experiments were carried out observe geometry of nets and fishing operating system by catcher boats. The obtained results are summarized as follows : The Vertical net opening of fore wing net, wing net, inside wing net, square, fore bag net, flapper, after bag net of the labor saving improved net according to the distance between catcher boats were varied in the range of 5.0${\sim}$7.8, 14.4${\sim}$21.1, 16.2${\sim}$21.2, 14.0${\sim}$17.3, 11.7${\sim}$13.9, 5.4${\sim}$6.9, 8.2${\sim}$9.8m respectively, varied in the range of 50${\sim}$78, 25${\sim}$36, 24${\sim}$31, 31${\sim}$38, 61${\sim}$73, 71${\sim}$91, 87${\sim}$104% of the actual ratio of net opening in each part. Labor saving improved net was performed instant net opening in fore wing net and maintained stable net opening and towing depth by means of attached net pendant. Also, it was minimized as net pocket phenomenon leading to guide anchovy for more catch by means of attached body net. The opening in accordance with distance between catcher boats and towing speed. The catch of labor saving improved net was increased than traditional net due to decrement of net resistance by improvement of bag net leading to increasement of towing speed and reduction of escape anchovy as well as improve nets of whole operation system.