• Proceedings of the Korean Society of Computer Information Conference
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• 2020.07a
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• pp.17-18
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• 2020

본 논문에서는 산업 현장에서 사용되는 기계들의 이상을 감지하고 잔존수명을 예측하는데 사용되는 중요한 지표 중 하나인 체인의 신율을 측정된 소음을 통해 계산하려고 한다. 본 연구에서는 Edge에서 측정한 소음데이터를 기반으로 스텝 체인의 특성을 고려하여 소음데이터의 파형을 분석하여 체인으로부터 발생되는 특징을 감지하고 해당 특징을 이용하여 대역통과필터와 최소분산을 이용하여 스텝 체인의 신율을 측정한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.3
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• pp.77-82
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• 2018

This paper is concerned with the performance analysis of a modified stop-and-go generalized multi-modulus algorithm (MSAG-GMMA) adaptive blind equalization algorithm with variable step size. The proposed algorithm multiplies the fixed step size by the error signal of the decision-oriented algorithm in the equalization coefficient update equation, and changes the step size according to the error size. Also, the MSAG-GMMA having a fixed step size is operated so as to maintain a fast convergence speed from a certain threshold to a steady state by determining the error signal size of the decision-directed algorithm, and when the MSAG-GMMA to work To evaluate the performance of the proposed algorithm, we use the ensemble ISI, ensemble-averaged MSE, and equalized constellation obtained from the output of the equalizer as the performance index. Simulation results show that the proposed algorithm has faster convergence speeds than MMA, GMMA, and MSAG-GMMA and has a small residual error in steady state.

• The Transactions of the Korean Institute of Power Electronics
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• v.11 no.3
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• pp.209-215
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• 2006

Now, in this paper, going to present you with an Idea related to a new inverter of multi-step voltage source, that Is, the double-connected 12-step inverter with an auxiliary circuit. It possibly can be 24-step inverter with 3-phase voltage source which will enable us make full application even to medium and high power-level Motor drive, UPS, STATCOM, SVC, etc. in which the PWM method could not be employed. 24-step operation can be obtained from the link between the existing 12-step inverter and the additional auxiliary circuit in which the transformer of auxiliary circuit generates ripple voltage delivered to the inverter. Through a lot of experiments and simulations, (from which the validity of this scheme is confirmed,) we came to the conclusion that the increase of the primary winding number on transformer by 2N(N=1,2,3....) leads to the 12M-step(M=2,3,4...) inverter. The validity of the proposed scheme is confirmed by the simulated and experimental results.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.1
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• pp.8-13
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• 2003

In this paper, suitablility of 1 GHz CISPR limits establishment fur broadcast communication quality protection is examined and the optimum turn step resolution of EUT for spurious measurement of frequency above 1 GHz to increase the accuracy of maximum values extraction is examined. As a result of 500 MHz and 1.7 GHz clock speed personal computer of micro-processor measurement, optimum turn step resolution extracted by National Institution of National Instrument of Standard & Technology(NIST) Koepke method is estimated 40 table positions per polarization in 500 MHz. And in case of 1.7 GHz, step size is 36 table positions. Prediction of turn step size required for fully scan method in gjgahertz measurement will increase measurement accuracy and reduce considerable measurement time as well.

• The Journal of the Acoustical Society of Korea
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• v.32 no.6
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• pp.518-524
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• 2013

In this paper, we propose a variable step size algorithm to enhance the normalized subband adaptive filter which has been proposed to improve the convergence characteristics of the conventional full band adaptive filter. The well-known Kwong's variable step size algorithm is simple, but shows better performance than that of the fixed step size algorithm. However, in case that large additive noise is present, the performance of Kwong's algorithm is getting deteriorated in proportion to the amount of the additive noise. We devised a variable step size algorithm which does not depend on the amount of additive noise by exploiting a normalized adaptation error which is the error subtracted and normalized by the estimated additive noise. We carried out a performance comparison of the proposed algorithm with other algorithms using a system identification model. It is shown that the proposed algorithm presents good convergence characteristics under both stationary and non-stationary environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.3
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• pp.443-448
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• 2022

This paper presents a subband affine projection algorithm with variable step size to improve convergence performance in adaptive filtering applications with long adaptive filters and highly correlated input signals. The proposed algorithm can obtain fast convergence speed and small steady-state error by using different step sizes for each adaptive sub-filter in the subband structure to which polyphase decomposition and noble identity are applied. The step size derived to minimize the mean square error of the adaptive filter at each update time shows better convergence performance than the existing algorithm using a variable step size. In order to confirm the convergence performance of the proposed algorithm, which is superior to the existing algorithm, computer simulations are performed for mean square deviation(MSD) for AR(1) and AR(2) colored input signals considering the system identification model.

• Korean Journal of Applied Biomechanics
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• v.18 no.1
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• pp.73-83
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• 2008

The purpose of this study was to investigate kinematic variables of three types of volleyball jump blocking motions through 3D video analysis. The subjects participated in this study were 7 male university volleyball players and 7 male physical education majors. 1. Regardless of blocking types, peak vertical velocity and jump height in the skilled group were faster and higher than the unskilled group. 2. The skilled group was flexed lower than the unskilled group at E2 of the hip, knee, and ankle joint during the cross over step blocking. 3. In all types of step, the peak angular velocity of the hip, knee, and ankle joint was showed at E2. 4. The skilled group was slower than the unskilled group at E2 of the angular velocity of the hip, knee, and ankle joint during cross over step blocking. In conclusion, the cross over step blocking in which the use of the upper extremities was relatively more available was effective to improve a defence skill for the jump height.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.7
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• pp.739-747
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• 2007

Dual-mode bandpass filter was designed by using periodic stepped impedance ring resonator with step perturbation. The periodic stepped impedance ring resonator has the effects of size reduction and $2^{nd}$ harmonic suppression by changing characteristic impedance ratio. The perturbation for dual-mode generation was also easily controlled by characteristic impedance ratio, and the variation of dual-mode resonant frequencies and attenuation pole frequencies were analyzed by the effect of step perturbation. Chip capacitors were used for input/output coupling, and the variation of center frequency by the coupling capacitance and step perturbation was also considered. From the results, two types of 2 GHz dual-mode bandpass filter were fabricated in size of $14{\times}14mm^2$, those have different attenuation poles and bandwidths. The measured results of proposed bandpass filters showed a good agreement with the calculated estimations, and those have insertion loss of 2.52, 0.52 dB and 3 dB bandwidth of 4.03, 15.02 %, respectively.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.4
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• pp.1-9
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• 2009

This paper investigates inelastic lateral-torsional buckling of stepped beams subjected to uniformly distributed load and end moments. A three-dimensional finite-element program ABAQUS (2007) and a regression program MINITAB(2006) were used to analytically develop new design equation for singly and doubly stepped beams with simple boundary condition. The flanges of the smaller cross-section in the stepped beams were fixed at 30.48 by 2.54 cm, whereas the width and thickness of the flanges of the larger cross-section varied. The web thickness and height of the beams were kept at 1.65 cm and 88.9 cm, respectively. The ratios of the flange thickness, flange width, and stepped length of beam are considered with analytical parameters. Two groups of 27 cases and 36 cases, respectively, were analyzed for doubly and singly stepped beams in the inelastic buckling range. The combined effects of residual stresses and geometrical imperfection on inelastic lateral-torsional buckling of beams are considered. The distributions of residual stress of the cross-section is same as shown in Pi and Trahair (1995) and the initial geometric imperfection of the beam is set by central displacement equal to 0.1% of the unbraced length of beam. The comparisons between results from proposed equations and the results from finite element analyses were presented in this paper. The maximum differences of two results are of 13% for the doubly stepped beam and 10% for the singly stepped beam. The proposed equations definitely improve current design methods for the inelastic lateral-torsional buckling problem and increase efficiency in building and bridge design.

• Journal of the Korean Society for Railway
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• v.15 no.4
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• pp.352-356
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• 2012

Heights of a platform above the rail for the passenger train in the country are classified into two categories such as the low level (500mm; mainline) and the high level (1,135mm; metropolitan subway line) platforms. In order to operate similarly both a mainline railroad and a metropolitan subway line, as the requisite door safety system, it is necessary to develop the doorstep equipment of the rolling stock regardless of both the low and high level platforms. In this study, Structural analysis and mechanical strength test of doorstep equipments used for two types of platforms are performed on the supposition that the train only for the low level platform could stop in the both low and high level platforms.