• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.1
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• pp.39-46
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• 2014

In this paper, to operate 2.4 GHz Inverted-L antenna with On-Board Broadband characteristics is proposed. The antenna was designed on the system board, the bandwidth by adjusting the reactance of the antenna that was formed common-mode and differential-mode on the antenna stubs has been improved. The system size is $80mm{\times}60mm$, the size of the antenna was limited to $30mm{\times}60mm$, the thickness of FR4 dielectric substrate is 0.8 mm, FR4 dielectric constant 4.4 is used. The experimental results, the bandwidth from 17.2 to 24.1 %, the gain is 3.01~4.71 dB, omni-directional radiation pattern characteristics were obtained. By a mobile terminal design applying the results of the paper, the handset's price competitiveness and production efficiency can be improved.

• Journal of Ocean Engineering and Technology
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• v.24 no.4
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• pp.47-52
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• 2010

In this paper, the shapes of windsurfing boards are proposed for the promotion of their public utilization. Initially, we investigated the principal dimensions of 1,500 windsurfing boards that were produced in the last six years to categorize the characteristics of the boards. Then, model tests were performed in a circulating water channel to determine the resistance characteristics and the flow phenomena, including the wetness of the decks. After analyzing the principal dimensions and the results of the tests of existing windsurfing boards, we proposed four public board shapes that resulted from changing the shapes of the nose and rail and protecting the deck of free-ride boards from wetness. Finally, we predicted the performance of the four proposed windsurfing boards.

• Proceedings of the Korean Institute of Interior Design Conference
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• 1999.04a
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• pp.114-117
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• 1999

The purpose of this study was to compare with the characteristics of Wumul-maru components in upper class Chosun dynasty. Physical trace method was used for this study. The samples were taken from the Sarang-taechong of 6 traditional Korean houses, Yunkyungdang, the ancient Chusa estate, Sunkyojand, Chunghyodang, Yangjindang, Unjoru. The major findings were summarized as follows; 1) Regarding to the scale characteristics, the number of changguit'ul(long board) was 1, chungguit'ul(middle-length board) 5, tongguit'ul(center board) 8m and maruno. 98, and the size of changguit'ul was 253$\times$4478mm, chungguit'ul 182$\times$2396mm, tongguit'ul 179$\times$2310mm, and marunol 247$\times$574mm. 2) Regarding to the proportion characteristics, the proportion of changguit'ul was 1:18.2, chungguit'ul 1:16.7, tongguit'ul 1:12.9, and marunol 1:2.62 and the proportion of components was 1:3:4:17.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.14 no.6
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• pp.18-25
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• 2000

This paper describes the design and fabrication of a home-panel board for electromagnetic compatibility which can protect home-electric appliances from transient voltages and power line noise. The proposed panel board include a transient voltage blocking device and a EMI filter which consisted of varistors, capacitors, and bus line inductance.A performance test of the prototype panel board, blocking characteristics to transient voltages and reduction characteristics to power line noise, are carried out by using a combination surge generator standardized in IEC and a network analyzer.The results showed that the proposed panel board is satisfied with the surge immunity level of IEC 61000-4-5, and has an over 20[dB] noise reduction performance in ranges from 150[kHz]∼30[MHz].

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.27 no.9
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• pp.36-43
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• 2013

The prevalence of electronic devices in our modern life is accompanied with the generation of harmonics caused by the nonlinear characteristic load. Especially, the employment of LED have brought the rapid use of SMPS. SMPS is used for supplying the constant DC electric power to the LED display board, but it has a big problem which gives birth of harmonics causing by its high-speed switching. measurement HIOKI 3196 equipment to solve these harmonics were measured. In this study, we are LED Display Board Load Measuring the impedance response with $X_L$ changes for removing harmonics in the measured. And we adopted the suitable passive filter by the impedance response characteristic obtained in the $X_L$ variation experiments. We are trying to deeply the application of passive harmonic filter characteristics that generation in the LED Display Board through EDSA LED simulation.

• The Journal of Asian Finance, Economics and Business
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• v.8 no.5
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• pp.627-637
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• 2021

This research extends the literature on the effect of board characteristics and ownership structure on audit fees; these factors affect the firm's agency costs and how the auditor assesses various risks, hence the audit efforts and fees. The paper introduces political connections as a determinant of audit fees for the first time in Jordan, where the political connection is prevalent and affects decision making on the Jordanian boards. The sample consists of 109 manufacturing and service firms listed on the Amman Stock Exchange (ASE) over the years 2012-2019. Data is obtained from the ASE and the company's annual reports. Board characteristics are measured by board size, independence, leadership duality, meetings frequency, political connections, and audit committee. Ownership structure was measured by concentration, foreign ownership, and Institutional ownership. The study hypotheses were tested by using Generalized Least Squares regression. The Findings showed that larger boards, politically connected firms, and firms with leadership duality are more likely to pay higher fees. Besides, Firms with greater foreign ownership pay less fees, whereas the rest of the variables are insignificant. Results suggest that political connections play a major role in determining audit fees; this provides a recommendation to policymakers in Jordan to reconsider regulations regarding political connections.

• Journal of Korean Society for Atmospheric Environment
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• v.9 no.3
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• pp.191-199
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• 1993

This paper describes the results of a systematic study to determine the characteristics of particle generated from various types of asbestos containing material(ACM) and manmade fiber material(MMFM) during operations of cutting and grinding in laboratory and workplace. Tests were conducted with a specially designed glove box which allowed complete sampling of the generated asbestos fibers. Specificially, air measurements were made during ACM and MMFM installation in building. All personal air samples collected were identified by polarized light microscopy(PLM), X-ray diffraction(XRD) and scanning electron microscope with energy dispersive X-ray analysis(SEM/EDXA). Also, the samples were counted by phase contrast microscope(PCM) in order to compare the results with the permissible exposure standard for workplace. Results indicate that the characterisitcs of fibers found in the roofing sheet, the ceiling and the wall insulation boards were identical to those of asbestos, while the characteristics of fibers found in the ceiling insulation board, the floor tile and the sprayed on insulation products in parking area were identical to those of asbestos, while the characteristics of fibers found in the ceiling insulation board, the floor tile and the sprayed on insulation products in parking area were identical to those of rock wool. The concentrations of airborne fibers from various building materials cut by a grinder for 5 minutes were in the ranges of 0.09 $\sim$ 1.71 fibers/cc(f/cc). The highest concentration(1.71f/cc) was found during grinding the wall insulation board which also contains rock wool. The airborne fiber concentrations generated by installing at workplace were ranged from 0.0009 to 0.029 f/cc. All asbestos fibers from the ceiling insulation board at workplace were less than 20$\mu$m in length and more than 20% of them had the average aspect ratio greater than 20. Therefore, for the purpose of decreasing asbestos and man-made fiber concentrations at the workplace, the ceiling and wall board should use strong binding material to increase the binding force with fiber. Also, the permissible exposure standard for workplace(2.0f/cc) in Korea should be constituted below the maximum avaiable concentration measured at glove box.

• The Journal of Korean Society for Radiation Therapy
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• v.26 no.1
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• pp.37-42
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• 2014

Purpose : At the time of the pelvis cancer radiation treatment using the belly board, set-up error is large because of a prone position. In order to improve the reproducibility, we made Vac-lock type belly board. In this study, we attempt to validate its utility. Materials and Methods : We compared belly board and Vac-lock type belly board through the OBI. OBI was performed three times with entire course of treatment and the setup errors in the direction of X axis, Y axis, Z axis were recorded and calculated the distance from the isocenter. Results : X axis, Y axis, Z axis setup errors with existing belly board were 0.32 cm, 0.41 cm, 0.29 cm. The setup errors with the vac-lock type belly board were 0.12 cm, 0.19 cm, 0.17 cm. Further, errors of 0~0.29 cm were increased from 48% to 83% when using VLT belly board. Error of 0.5 cm or more was reduced from 21% to 2%. Conclusion : Vac-lock type belly board is able to maintain the efficacy of existing and create to match the characteristics of the patient. Therefore We think that vac-lock type belly board is very useful in pelvic cancer patients.

• Journal of IKEEE
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• v.22 no.3
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• pp.874-877
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• 2018

Many SMDs (surface mount device) are mounted and mutually connected on a PCB (printed circuit board). System performance degrades when their transmission characteristics are bad. Pads connecting a PCB and SMDs affects PCB transmission characteristics significantly, so pad should be properly aligned to optimize impedance matching. In this paper, effects on PCB transmission characteristics are simulated by pad alignment. When frequency is relatively low, pad alignment seldom affect PCB transmission characteristics, but it affects more and more when frequency or pad size becomes larger. Therefore, pad alignment should be carefully chosen based on target frequency and pad size. Especially, the proposed edge-aligned pad is generally more advantageous over the conventional centered-aligned pad in 12~16 GHz Ku-band frequency.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.384-389
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• 2008

In this paper, we propose a UML modeling of ATO on-board software. An automatic train operation (ATO) system is a real-time control system, which operates a train without a manual operation by a driver. For the safe and comfortable service, real-time embedded software for ATO on-board equipment should have both of high performance and reliability. UML-based object-oriented modeling technique is introduced and used widely to design software that satisfies this requirement. We used Rhapsody, which is a modeling tool for real-time embedded software, to model the construction and the behavior of ATO on-board equipment. As a result, ATO on-board software which performs the profile calculation and the real-time speed control is designed and implemented. The brief modeling result including behavioral characteristics and the simulation results are presented.