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Catching efficiency of biodegradable trammel net for swimming crab (Portunus trituberculatus) in the Yeonpyeong fishing ground of Korea (연평어장에서 생분해성 꽃게 삼중자망의 어획성능)

  • Kim, In-Ok;Lee, Gun-Ho;Cho, Sam-Kwang;Cha, Bong-Jin;Sohn, Byung-Kyu
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.48 no.4
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    • pp.322-336
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    • 2012
  • To study the catching efficiency of biodegradable trammel net for swimming crab (Portunus trituberculatus), three types (biodegradable, monofilament and multifilament) of trammel nets were used in the field test, and the tests were carried out 16 times with two different mesh sizes (105mm and 160mm) in the Yeonpyeong fishing ground of Korea, 2009~2011. The catching efficiency of three type nets was analyzed by catch in number, catch in weight and average weight per individual of small and large size swimming crab by net types and mesh sizes. Statistical T-test was also carried out to verify the efficiency between the three types of nets. The results are as follows. The catch in number of swimming crab was 24,667 and formed about 81.0% of total catch. Of all swimming crab catch, small swimming crabs with less than 64mm in carapace length which is a prohibited landing size by law formed 48.1%, larger swimming crabs with more than 64mm in carapace length which is a landing size formed 51.9%. In 105mm mesh size trammel net test, the catch share in number of small size swimming crab by biodegradable trammel net was 47.5% in comparison with multifilament trammel net and 74.2% in comparison with monofilament trammel net, so biodegradable trammel net has more protective effects on small size swimming crab than other types of trammel nets. The protective effects for small size swimming crab by biodegradable trammel net was 25.8~52.5% in comparison with other types of trammel nets. The catch share in weight of large size swimming crab by biodegradable trammel net was 98.3% in comparison with multifilament trammel net and 92.3% in comparison with monofilament trammel net, so biodegradable trammel net has a similar catch efficiency to multifilament trammel net. The results of 160mm mesh size trammel net test have shown similar results of 105mm mesh size trammel net test. This study shows that biodegradable trammel net is a more useful fishing gear than multifilament and monofilament trammel net because biodegradable trammel net has lower catch rate than other types of nets in small size swimming crab and similar catch rate than multifilament trammel net which is a well used net by fishermen.

The Effect of Corporate Social Responsibility on Corporate Image : Large versus Small and Medium Sized Company (기업의 사회적 책임활동이 기업이미지에 미치는 영향 : 대기업과 중소기업의 비교)

  • Park, Sang-June;Jang, Hwa-Young;Lee, Yeong-Ran
    • Korean Management Science Review
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    • v.29 no.1
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    • pp.15-32
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    • 2012
  • Previous studies have examined the relationship between corporate social responsibility and corporate's business performance (especially, consumers' corporate evaluation). According to them, the corporate social responsibility influences the consumers' corporate evaluation. A small and medium sized company as well as a large company is asked to conduct socially responsible actions, however, it is not easy to find a study that focuses on whether the effect of the corporate social responsibility on the consumers' corporate evaluation is different by the size of company. In this paper, we classified the corporate social responsibility into the four dimensions (economic responsibility, legal responsibility, ethical responsibility, philanthropic responsibility), and investigate the differences between a small and medium sized company and a large company in the effects of the four dimensions on the consumers' corporate evaluation. We showed that the each dimension of the corporate social responsibility had an positive effect on the corporate image regardless of the size of company. In addition, we demonstrated that the effects of the four dimensions on the company image were different by the size of company; The legal responsibility and ethical responsibility are more influential to the corporate image of a large company than to that of a small and medium sized company, however, the effects of economic responsibility and philanthropic responsibility are not different by the size of company.

Fabrication of Ultra Small Size Hole Array on Thin Metal Foil (초미세 금속 박판 홀 어레이 가공)

  • Rhim S. H.;Son Y. K.;Oh S. I.
    • Transactions of Materials Processing
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    • v.15 no.1 s.82
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    • pp.9-14
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    • 2006
  • In the present research, the simultaneous punching of ultra small size hole of $2\~10\;{\mu}m$ in diameter on flat rolled thin metal foils was conducted with elastic polymer punch. Workpiece used in the present investigation were the rolled pure copper of $3{\mu}m$ in thickness and CP titanium of 1.5fm in thickness. The metal foils were punched with the dies and arrays of circular and rectangular holes were made. The process set-up is similar to that of the flexible rubber pad farming or Guerin process. Arrays of holes were punched successfully in one step forming. The punched holes were examined in terms of their dimensions. The effects of the wafer die hole dimension and heat treatment of the workpiece on ultra small size hole formation of the thin foil were discussed. The process condition such as proper die shape, pressure, pressure rate and diameter-thickness ratio (d/t) were also discussed. The results in this paper show that the present method can be successfully applied to the fabrication of ultra small size hole away in a one step operation.

A Study on Attitude Heading Reference System Based Micro Machined Electro Mechanical System for Small Military Unmanned Underwater Vehicle

  • Hwang, A-Rom;Yoon, Seon-Il
    • Journal of Advanced Marine Engineering and Technology
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    • v.39 no.5
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    • pp.522-526
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    • 2015
  • Generally, underwater unmanned vehicle have adopted an inertial navigation system (INS), dead reckoning (DR), acoustic navigation and geophysical navigation techniques as the navigation method because GPS does not work in deep underwater environment. Even if the tactical inertial sensor can provide very detail measurement during long operation time, it is not suitable to use the tactical inertial sensor for small size and low cost UUV because the tactical inertial sensor is expensive and large. One alternative to INS is attitude heading reference system (AHRS) with the micro-machined electro mechanical system (MEMS) inertial sensor because of MEMS inertial sensor's small size and low power requirement. A cost effective and small size attitude heading reference system (AHRS) which incorporates measurements from 3-axis micro-machined electro mechanical system (MEMS) gyroscopes, accelerometers, and 3-axis magnetometers has been developed to provide a complete attitude solution for UUV. The AHRS based MEMS overcome many problems that have inhibited the adoption of inertial system for small UUV such as cost, size and power consumption. Several evaluation experiments were carried out for the validation of the developed AHRS's function and these experiments results are presented. Experiments results prove the fact that the developed MEMS AHRS satisfied the required specification.

Reducing Computational Complexity for Local Maxima Detection Using Facet Model (페이싯 모델을 이용한 국부 극대점 검출의 처리 속도 개선)

  • Lee, Gyoon-Jung;Park, Ji-Hwan;Joo, Jae-Heum;Nam, Ki-Gon
    • Journal of the Institute of Convergence Signal Processing
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    • v.13 no.3
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    • pp.130-135
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    • 2012
  • In this paper, we propose a technique to detect the size and location of the small target in images by using Gaussian kernel repeatedly. In order to detect the size and location of the small target, we find the local maximum value by applying the facet model and then use the $3{\times}3$ Gaussian kernel repeatedly. we determine the size of small target by comparing the local maximum value $D_2$ according to the number of iteration. To reduce the computational complexity, we use the Gaussian pyramid when using the kernel repeatedly. Through the experiment, we verified that the size and location of the small target is detected by the number of iterations and results show improvements from conventional methods.

A Running Stability Test of 1/5 Scaled Bogie using Small Scale Derailment Simulator (소형탈선시뮬레이터 상에서의 1/5 축소대차의 안정성 해석)

  • Eom, Beom-Gyu;Lee, Se-Yong;Lee, Young-Yeob;Kang, Bu-Byoung;Lee, Hi-Sung
    • Proceedings of the KSR Conference
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    • 2011.10a
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    • pp.1905-1913
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    • 2011
  • The dynamic characteristic of bogie that is driving system of railway vehicle is very important regarding decision of vehicle characteristics as running safety and comport. The dynamic characteristic test of bogie is tested on full size in place on field testing on track. But, the testing on the full size caused many problems. To overcome these problem by full size test, the Railway Safety Research Center in Seoul National University of Science & Technology developed 1/5 scale size of small scale derailment simulator and is currently testing running stability of 1/5 scaled bogie. Also To take effectively advantage of running stability test using small scale derailment simulator in actuality design and reliability estimation, it is necessary comparison and examination with field test and theoretical analysis result In this paper. to achieve running stability analysis of 1/5 scaled bogie on small scale derailment. the program using MATLAB that is fast compose and analysis the motion equation of Saemaul power bogie is developed. It is achieved analysis according to various specification (weight, size, suspension, etc..) and is evaluated corelation between test result and dynamic characteristic of actual railway vehicle.

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Using oscillatory shear to probe the effects of bidispersity in inverse ferrofluids

  • Ekwebelam, C.C.;See, H.
    • Korea-Australia Rheology Journal
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    • v.19 no.1
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    • pp.35-42
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    • 2007
  • The effects of particle size distribution on the magnetorheological response of inverse ferrofluids was investigated using controlled mixtures of two monodisperse non-magnetisable powders of sizes $4.6\;{\mu}m\;and\;80{\mu}m$ at constant volume fraction of 30%, subjected to large amplitude oscillatory shear flow. In the linear viscoelastic regime (pre-yield region), it was found that the storage and loss moduli were dependent on the particle size as well as the proportion of small particles, with the highest storage modulus occurring for the monodisperse small particles. In the nonlinear regime (post yield region), Fourier analysis was used to compare the behaviour of the $1^{st}\;and\;3^{rd}$ harmonics ($I_{1}\;and\;I_{3}\;respectively$) as well as the fundamental phase angle as functions of the applied strain amplitude. The ratio of $I_{3}/I_{1}$ was found to become more pronounced with decreasing particle size as well as with increasing proportion of small particles in the bidisperse mixtures. Furthermore, the phase angle was able to clearly show the transition from solid-like to viscous behaviour. The results suggested that the nonlinear response of a bidisperse IFF is dependent on particle size as well as the proportion of small particles in the system.

The Difference of the Inventories Assets Turnover Change Ratio According to the Firm Size (기업 크기에 따른 재고자산회전 변화율의 차이)

  • Lee, Jihye;Choi, Young-Keun;Kim, Pansoo
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.38 no.2
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    • pp.72-81
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    • 2015
  • This paper studied the differences of the inventories asset turnover change ratio and several characteristics variable between large and small manufacturing firm group. Large and small firm group were determined based on number of labors and asset size. Several characteristics variable of firms such as assets size, sales growth rate, return on assets, leverage ratio, credit rating and age of firm were used to find out the differences of firm group. As a result, the inventory asset turnover change ratio of large firm was 5.16% and that of the middle and small firm was 9.3%. For the large firm, sales growth rate, ROA and credit rating affect inventory assets turnover change ratio. For the middle and small sized firm, Assets size, sales growth rate and credit rating affect inventory assets turnover change ratio. Using this result, we can say that manufacturing company need to consider their firm size and their characteristics to make their own operation strategy of inventory.

A Study on the Multi-Layer Effect of Regulation : Focusing on the Restriction on Conglomerate Firms' Participation in Public Software Procurement (기업 규제의 다층적 효과 연구 : 공공 소프트웨어 사업 대기업참여제한제도를 중심으로)

  • Yoo, Hoseok;Park, Gangmin;Kim, Jounyoun;Lee, Samyoul
    • Journal of Information Technology Services
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    • v.18 no.4
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    • pp.39-53
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    • 2019
  • This article analyzes the effects of regulation that restrict the conglomerate firms to participate in the public procurement of software. The regulation was implemented in 2013, and this article analyzes five years of firm performance before and after 2013 through DID (difference-in-difference method). In particular, this article analyzes how restrictions on conglomerate firms' participation in public software procurement affect middle and small firms performance. As a result, small-size firms achieve relatively positive results in private sector revenues compared to mid-size firms. However, there was no significant difference between the mid-size and small-size firms in profit margin. This study implies that the new policy is needed to improve the small and medium-size firms revenues on the private market by leveraging the public procurement market which restricted the conglomerate firms to participate. This can be done by complementing the regulation in line with servitization paradigm.

Morphological Characterization of small, dumpy, and long Phenotypes in Caenorhabditis elegans

  • Cho, Joshua Young;Choi, Tae-Woo;Kim, Seung Hyun;Ahnn, Joohong;Lee, Sun-Kyung
    • Molecules and Cells
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    • v.44 no.3
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    • pp.160-167
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    • 2021
  • The determinant factors of an organism's size during animal development have been explored from various angles but remain partially understood. In Caenorhabditis elegans, many genes affecting cuticle structure, cell growth, and proliferation have been identified to regulate the worm's overall morphology, including body size. While various mutations in those genes directly result in changes in the morphological phenotypes, there is still a need for established, clear, and distinct standards to determine the apparent abnormality in a worm's size and shape. In this study, we measured the body length, body width, terminal bulb length, and head size of mutant worms with reported Dumpy (Dpy), Small (Sma) or Long (Lon) phenotypes by plotting and comparing their respective ratios of various parameters. These results show that the Sma phenotypes are proportionally smaller overall with mild stoutness, and Dpy phenotypes are significantly stouter and have disproportionally small head size. This study provides a standard platform for determining morphological phenotypes designating and annotating mutants that exhibit body shape variations, defining the morphological phenotype of previously unexamined mutants.