• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1994.10a
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• pp.118-132
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• 1994

This paper investigates a new method to design blocker geometry in rib-web type closed die forging. By examining various forging and blocker geometries, it was found that blocker geometry can be generated by eliminating high frequency mode from finisher geometry. In order to formalize the procedure, low pass filters, which can convert finisher to blocker geometry, are proposed. Also discrete Fourier transform is used for computational efficiency. The blocker geometry designed by the present method are compared with the one by an experienced designer. The blocker geometries are also validated by using FEM simulation. Present results shows that the frequency approach may offer a promising method to design blocker automatically.

• Transactions of Materials Processing
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• v.13 no.8
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• pp.671-677
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• 2004

For the large reduction in tube cross section, the tube drawing process is usually performed by two successive passes, so called first drawing and second drawing. In multi-pass drawing process, the reduction balance is important to prevent drawing cracks. Therefore in this study, the model for uniform reduction distribution in two-pass drawing process has been developed on the basis of cross sectional variation of drawn tube. For the given product geometry the model provides optimal diameter and thickness that can evenly distribute drawing reductions. The capability of model is well confirmed by finite element analysis of tube drawing process. Criteria curves at various limit strains to determine whether the drawn tube would fail during drawing process are also proposed by using newly developed model.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.91-93
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• 2008

In this paper, novel phase angle following algorithm for the single phase grid-connected inverter is proposed. Gird-connected inverter needs phase angle detection for synchronization grid voltage with the inverter output. In case of single phase grid-connected inverter, zero crossing detection and virtual 2-phase PLL using digital all pass filter or digital low pass filter are used conventionally. But these methods have a weakness for harmonics, noises and ripples. The proposed method of PLL achieve DFT(Discrete Fourier Transform) using Goertzel algorithm. It can extract fundamental voltage of grid. As a results, it can obtain phase angle using digital all pass filter without effect of harmonics, noises and ripples. Simulation results are presented to demonstrate the effectiveness of the proposed algorithm.

• Journal of Korean Orthopaedic Sports Medicine
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• v.3 no.1
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• pp.42-48
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• 2004

The Football, popular spots in korea, increasing population to participate club activity caused various injuries with the consequence. Investigating relationship between biomechanics of the skills using football and injuries, we propose helpful methods to prevent injuries. Also authors point out the differences between outdoor and indoor football and women's football, and study skills using football like kick, pass, heading and head injury with researching literatures.

• Journal of the Korea Society for Simulation
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• v.10 no.4
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• pp.21-30
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• 2001

In this paper, EMI measurement, the STGU simulation being conducted, filter design, its characteristics, and its implementation to the PCB, and finally test results are discussed. When the low pass filter was implemented within the STGU, the power of EMI decreased more than 20dBm. Finally, when TE and MTIE, two important quality measure in synchronous reference clock, was assessed, ITU-T G813 requirement was satisfied. EMI(Electromagnetic Interface) is a measure of electomagnetic radiation from equipment in the range of 10KHz to 3GHz, and can cause unexpected reactions of electronics/electrical equipment. In this study, for safe and stable communication operation, a STGU (System Timing Generation Unit), which is a 2.5G SDH System and a major EMI source, was employed to simulate electromagnetic interface. Using Open-Site test, the power of fundamental frequency of EMI of interest and its harmonics were measured. Also, a low pass filter at cut-off frequency of 2GHz was specifically designed for this study to minimize the effect of EMI between electronic components.

• Journal of the Korean Institute of Telematics and Electronics
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• v.8 no.5
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• pp.20-26
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• 1971

A function relationship between the envlope rise time and Q v91ue of band pass filter is studied by using the time response to the step and sinusodal inputs. It is discovered that the above relationship is linear in the very low frequency band. The filter was constructed by the Analog computer so as to do the function of 2nd order RC active band pass.

• IEIE Transactions on Smart Processing and Computing
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• v.3 no.3
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• pp.128-134
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• 2014

A real-time, continuous-scale image interpolation method is proposed based on a bilinear interpolation with directionally adaptive low-pass filtering. The proposed algorithm was optimized for hardware implementation. The ordinary bi-linear interpolation method has blocking artifacts. The proposed algorithm solves this problem using directionally adaptive low-pass filtering. The algorithm can also solve the severe blurring problem by selectively choosing low-pass filter coefficients. Therefore, the proposed interpolation algorithm can realize a high-quality image scaler for a range of imaging systems, such as digital cameras, CCTV and digital flat panel displays.

• Journal of electromagnetic engineering and science
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• v.14 no.4
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• pp.387-392
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• 2014

In this paper, a size-reduced Wilkinson balun with wide harmonic-suppressed band is presented. An accurate analysis of the parallel coupled line with an open stub (PCL-OS) is carried out. The PCL-OS structure shows excellent low pass filter and harmonic-suppression characteristics, which is useful for designing a low pass filter unit cell (LUC) with a reduced size. The designed Wilkinson balun at a 2.45 GHz center frequency not only shows an excellent harmonic suppression including the 5th harmonics up to 14 GHz over 15 dB, but it also has an area reduced to 48% of the conventional one.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.649-651
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• 2016

Wireless Sensor Network(WSN) consists of spatially distributed sensors to monitor physical conditions, such as temperature, light and motion, and to pass their data through the network to a base station. Each battery equipped node is consumed to pass their data to their neighbors. We are gathering the amount of energy that was consumed to gather data and to pass it This paper describes processes of energy consumption of WSN in Matlab.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.8
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• pp.740-743
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• 2003

A multi-layer ceramic (MLC) chip type band-pass filter (BPF) is presented. The MLC chip BPF has the benefits of low cost and small size. The BPF consists of coulped stripline resonators and coupling capacitors. The BPF is designed to have an attenuation pole at below the passband for a receiver band of IMT-2000 handset. The computer-aided design technology is applied for analysis of the BPF frequency characteristics. The passband and attenuation pole depend on the coupling between resonators and coupling capacitance. The frequency characterics of the passband and attenuation pole are analyzed with the variation of the coupling between resonators and coupling capacitance. An equivanlent circuit and structure of MLC chip BPF are proposed. The frequency characteristics of the BPF is well acceptable for IMT-2000 application.