• Journal of the Korea Furniture Society
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• v.19 no.3
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• pp.211-218
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• 2008

This experiment was carried out to investigate the effect of internal holes on the bending strength of PB. The diameters of holes are 0mm to 13mm. The locations of holes are 1/8 to 4/5 point horizontally from sample end and are 1/5 to 4/5 vertically from sample surface, the numbers of holes are 1 to 4 pcs. In the size of internal holes, the bending strengths of PB were decreased significantly with the increase of diameter of holes, and the relationship between diameters(D) of holes and bending strength (${\sigma}_b$) of PB was ${\sigma}_b=-11D+168.8$ ($r^2=-0.99^{**}$). The effects of hole-locations and hole-numbers on the bending strengths of PB were large. and so they should be considered as major factors for the jointing design of PB.

• Journal of Electrical Engineering and Technology
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• v.6 no.6
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• pp.849-852
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• 2011

This paper investigates a method to tackle the resonance problems of the rectangular power-bus structure(PBS) using thin sheets loaded with periodic metal strips. The equivalent surface impedance of the proposed loading is calculated and involved in the expression of the impedance that accounts for in the PBS, in order to improve the resonance behavior of the original structure. The effects of the strips and the immediate surroundings are illustrated by a number of numerical experiments. Also the restrictions of the technique are addressed.

• Journal of the Korean Society of Safety
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• v.17 no.1
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• pp.94-98
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• 2002

This study aimed to search for the fundamental accident causes using a categorical analysis, a kind of statistical methods. As the analysis methods, correlation analysis, independence test and logistic regression analysis were used. And the SPSS package, a general-purpose mathematical library, was used to obtain statistical characteristics. As the result of this study, the accident causes associated with factor of 'lost working days' were factors such as 'employed periods', 'sex', 'type of accident', 'month'. In case of applying independence test method, the most important cause was the factor of 'month'. In case that logistic regression analysis method was applied, the cause contributed to the increase structure'. 'less than 6 month'. On the basis of these results, the plan for accident prevention and the proper investment for accident prevention expenditure could be carried out in each workshop.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.238-240
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• 2007

본 논문에서는 전자기파 산란 문제를 해석하는데 있어서 중요한 기법의 하나인 유한 차분 시간영역 해석방법(FDTD : Finite-Difference Time-Domain Method)을 이용하여 금속 차폐구조의 틈새인 개구를 통한 EMC 문제를 중점적으로 다루었다. 이와같은 3차원 FDTD를 이용한 전자파 산란 문제의 해석을 통한 연구는 통신 시스템의 차폐 방안과 전자파 내부침투 문제 해결을 위한 중요한 기반 작업이 될 것으로 기대된다.

• 한국정보통신설비학회:학술대회논문집
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• 2007.08a
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• pp.31-33
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• 2007

This work presents the simplified mechanism that the microstrip line generates the radiated emission which is one of the measures on the EMI levels. The electric currents on the metallization of the structure are input to the radiation integrals with the Green's functions being derived to consider the stratification of the microstrip. The simulated results suggest the method of the conceptualization on the RE characteristics of the signal trace in the PCB structure.

• Journal of Power Electronics
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• v.18 no.4
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• pp.997-1006
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• 2018

This paper proposes a transformerless photovoltaic (PV) power converter system based on the DC/AC boost inverter, which can solve the leakage current and second-order ripple power issues in single-phase grid-connected PV inverters. In the proposed topology, the leakage current can be decreased remarkably since most of the common-mode currents flow through the output capacitor, by-passing parasitic capacitors, and grounding resistors. In addition, the inherent ripple power component in the single-phase grid inverter can be suppressed without adding any extra components. Therefore, bulky electrolytic capacitors can be replaced by small film capacitors. The effectiveness of the proposed topology has been verified by simulation and experimental results for a 1-kW PV PCS.

• Journal of Korean Society for Quality Management
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• v.24 no.4
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• pp.141-155
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• 1996

In service industries, it is very hard to transform the quantified factor into qualified one. Nowadays, however, service industries employee various methods developed by the academic society to manage effectively. Therefore, we have focused our research on QFD that is applied to improve the flow of execution in customer complains in Air Lines which can be considered as the representation of Service Industries. QFD is a method of developing new service with response to the demand from customer thanks to the application of QFD. In this paper we decide the priority of the department for executing the customer service of Air Lines. After setting up the relations among departments, we analyze the problems caused by the contact between customers and departments.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1576_1576
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• 2009

We present the design of an EMI filter to mitigate the electrical noise from the power supply over a broadband of a few tens of KHz to 18GHz. Admitting that our approach is not apart from the standard technology of EMI filter, it is worth checking out how we can implement the filter that meets the challenging spec. on band of operation. The function of the EMI filter is well-depicted by its performance on the CE(Conducted Emission) and RE(Radiated Emission) suppression through tests which convince us of its application to power supplies of land, water and flying vehicles.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1567_1567
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• 2009

In this article, we deal with the IED(Intelligent Electronic Device) on the EMC aspect. Recognizing how expensive the thorough EMC work will be regarding the entire IED, we focus on the characteristics of RF signals moving along multiple TX-lines in one specified example of the typical IED structure, say, the layer of trace lines. Simplifying the real structure, we run a 3D EM program and analyze the properties of signals on the lines and interference due to the coupling between the neighboring lines.

• Journal of the Korea Furniture Society
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• v.17 no.2
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• pp.25-34
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• 2006

This experiment was carried out to investigate the high-frequency gluing characteristics of poly vinyl acetate emulsion adhesive(PVAc) on MDF edge-glued boards. The edge-glued boards were glued lengthwise with butt, scarf, or finger joint. The wastes of MDF boards were reused as board materials. The obtained results are summarized as follows; the bending strength of edge-glued MDF increased slightly with the HF heating time, but the economically desirable heating time was 6 minutes. The bending and tensile strength of edge-glued MDF were high with scarf, finger and butt joint, in order. The strength of finger jointed MDF showed 80% of scarf jointed MDF. The effects of location of finger joints on the bending strength of edge-glued MDF were larger than those of the numbers of finger joints. The bending strength of edge-glued MDF with one joint on the middle position showed 40% decrease in comparison with non-jointed MDF.