• The Journal of Fisheries Business Administration
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• v.39 no.1
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• pp.17-42
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• 2008

This study tried to build a structure model for the Korean flatfish aquaculture market by a system dynamics approach. A pool of several factors to influence the market structure was built. In addition, several reasonable factors related to the flatfish aquaculture market were selected to construct the causal loop diagram (CLD). Then the related stock/flow diagrams of the causal loop diagrams were constructed. This study had been forecasting a production price and supply, demand, and consumption volume for the flatfish market by a monthly basis, and then made some validation to the forecasting. Finally, four governmental policies such as import, storage, reduction of input, and demand control were tentatively evaluated by the created model. As a result, the facts that the demand control policy is most effective, and import and storage policies are moderately effective were found.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.4
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• pp.303-308
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• 2016

A light-emitting diode (LED) has been increasingly applied to various industrial fields and general lightings because of its high efficiency, low power consumption, environment-friendly characteristic and long lifetime. To drive this LED lighting, various types of power converters have been applied. Also, power factor correction (PFC) techniques play an important role in the power supply technology. In this paper, design and control of a DCM interleaved boost PFC converter is discussed. The proposed converter can reduce current ripples at input and output side by cancelling an each phase of inductor currents. Since the IC does not require the auxiliary winding of inductor for current detection, simple PFC circuit is achieved. Therefore, it contributes to increase efficiency and downsize the whole system volume, cost. Also, the performance of the proposed system is demonstrated through experiments.

• Tribology and Lubricants
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• v.21 no.2
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• pp.83-92
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• 2005

A piston assembly is very important because it directly receives the energy generated during combustion process. Surely, the friction and lubrication of piston-ring pack do an important role in the performance and fuel economy of an engine. In fact, the friction loss in piston-ring pack is the biggest portion to the whole engine friction. Therefore, the improvement of lubrication quality and friction loss in piston-ring pack will be directly related with the improvement in the performance and fuel economy of an engine. Meanwhile, the oil consumption and blow-by gas through piston-cylinder-ring crevices have to be controlled as less as possible. In these two aspects, the study on the optimized design of piston-ring pack has to be carried out. In this study, for the efficient design of piston-ring pack, it is focused to develop a basic computer program that predicts the inter-ring pressure, the motion of ring and the blow-by gas through a crevice volume model between adjacent rings, and the oil film thickness and the friction computed by lubrication theories.

• Journal of the Korean Society of Industry Convergence
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• v.11 no.1
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• pp.19-26
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• 2008

The gas-liquid mass transfer volumetric coefficients in gas-liquid agitated vessels with wire gauge impellers were measured to be compared with those in vessels with disk turbine and paddle impellers. Also mass transfer volumetric coefficients for disk turbine, paddle impeller and wire gauge impeller in cylindrical agitated vessel was measured over a wide range of Reynolds number from turbulent flow to transition regions. The effect of geometries on $k_La$ is clarified experimentally. Mass transfer volumetric coefficients $k_La$ depends only on the power consumption ($P_{gv}+P_{av}$) per unit volume.

• Proceedings of the KSR Conference
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• 2004.06a
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• pp.397-404
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• 2004

The higher costs of logistics in Korea than those of other developed countries have been considered as a main factor to reduce national competitiveness. In addition, the international logistics has become more important than before as trade across countries have increased with globalization. This study measured the rate of international logistics absorption as total trade volume compared total domestic consumption expenditure. The measure showed that USA($26\%$), japan($31\%$), and China($l12\%$) are important countries for Korea to cooperate for the international logistics and its standardization. However, for these countries, Korea is not important country in terms of the international logistics because the absorption rates of these countries to Korea are relatively very low as they shows $0.8\%$, $8\%$, $1.85\%$ in USA, China, and japan, respectively. Thus, we need international strategies in logistics fields to cooperate with these countries.

• Korean Journal of Human Ecology
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• v.9 no.1
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• pp.63-70
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• 2006

This study is a review of the clothing behavior of kidult group that is a new minority group in 21st century. Kidult is the compound word of kid and adult and refers the persons who have become adults but with the inclination to focus on childlike culture and consumption. As the background of the appearance of the kidult group these days, the prevalence of throwback fashions, high valuation of appearance, the phenomenon to prefer light things caused by economic depression, the individualism that does not care about others and the ageless phenomenon that the consumptions are mind age oriented, may be pointed out. The most prominent cloth behavioral characters of the kidult group are that they enjoy bounding color combinations such as candy color and. that cute t-shirts, crop pants and volume skirts of girlish look are easily found. Also, they enjoy toy-like ornaments and illustrated clothes or accessories and the school uniform fashion implying nostalgia for girl-hood and lovely make-up indicate the kidult inclination.

• ETRI Journal
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• v.31 no.3
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• pp.348-350
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• 2009

To fit the limited volume and power consumption of the passive radio frequency transmission system of the electronic time fuze, an improved coded mark inversion (CMI) is proposed in this letter. From the performance analysis, the energy transmission efficiency of this encoding method is at least 50% higher than that of CMI and NRZ. Finally, the experiment results show that by adopting this improved CMI, the change of DC voltage through magnetic coupling is lower than 0.2 V when the accuracy of data transmission is above 99.5%.

• The Journal of Information Systems
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• v.20 no.3
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• pp.1-24
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• 2011

Recently, six sigma has been widely adopted in a variety of industries as a disciplined, data-driven problem solving approach or methodology supported by a handful of powerful statistical tools in order to reduce variation through continuous process improvement. Also, data mining has been widely used to discover unknown knowledge from a large volume of data using various modeling techniques such as neural network, decision tree, regression analysis, etc. This paper proposes a six sigma methodology based on data mining for effectively and efficiently processing massive data in driving six sigma projects. The proposed methodology is applied in the hot stove system which is a major energy-consuming process in a "P" steel company for improvement of heat efficiency through reduction of energy consumption. The results show optimal operation conditions and reduction of the hot stove energy cost by 15%.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.1335-1336
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• 2008

A compact diode-pumped microchip(DPM) green light source which consist of pump LD, $Nd:YVO_4$, KTP and a built-in thermoelectric element has been fabricated for laser projection display. The volume of the source is as small as $0.7\;cm^3$ and we obtained the output power of 25mW with the average electric power consumption in pump LD of 304mW which correspond to the electrical-to-optical efficiency of 7.8%. Another approach using quasi phase matching(QPM) technique has been attempted. We obtained the output power of 90mW of green beam with 350mW pumping of a $Nd:YVO_4$ laser with 20-kHz rep. rate and 10-ns pulse duration. Detailed characteristics and issues of the DPM and QPM green light sources will be addressed.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.176-179
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• 2001

A portable bio-signal measurement system for 24-hours continuous health monitoring of the elderly and the disabled is presented. The measurement system has the functions of acquisition of various bio-signals such as ECG, EMG and EEG, wireless data transmission/receive and adjustment of parameters such as gain and cut-off frequency. The data is sent to a host computer or other device via a Bluetooth. The design targets of the developing system for volume and power consumption are $20{\times}30{\times}5(mm^3)$ and 8mW.