• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.3
• /
• pp.52-58
• /
• 2002

The purpose of condition monitoring and fault diagnosis is to detect faults occurring in machinery in order to improve the level of safety in plants and reduce operational and maintenance costs. The recognition performance is important not only to gain a high recognition rate bur a1so to minimize the diagnosis failures error rate by using off effective rejection module. We examined the problem of performance evaluation for the rejection scheme considering the accuracy of individual c1asses in order to increase the recognition performance. We use the Smith's method among the previous studies related to rejection method. Nearest neighbor classifier is used for classifying the machine conditions from the vibration signals. The experiment results for the performance evaluation of rejection show the modified optimum rejection method is superior to others.

• Proceedings of the IEEK Conference
• /
• 2004.06a
• /
• pp.249-252
• /
• 2004

Recently, wireless repeater with interference rejection has been considered for the next generation repeater. In this paper, adaptive interference rejection module suppressing interference in the 3G band is proposed. A novel adaptive rejection scheme is proposed and it is partially implemented by FPGA devices.

• Journal of Industrial Technology
• /
• v.18
• /
• pp.439-442
• /
• 1998

In this paper, we firstly suggested C&D (Common mode and Differential mode) model for the representation of a stereophonic signal. Then a measure of stereophonic channel separability is defined as the ratio of differential mode energy to total energy in frequency domain. After that, a new channel separability enhancement scheme is proposed by the control of common mode rejection. Finally, some experimental results are presented in order to verify our scheme.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.9 no.1
• /
• pp.60-67
• /
• 2000

An improved disturbance rejection control scheme is presented for minimizing the position error due to the repeatable runout disturbances in high density disk drive systems The proposed control algorithm is capable of attenuating repeatable disturbances which is one of the major detractors to hard disk drive quality and performance. This is achieved by a sys-tematic combination of an optimal feedback component and a feedforward preview component. The feedback component is designed where the emphasis is placed on robustness. The feedforward component is on the basis of a preview control comprised of a measured disturbance signals which leads to better disturbance rejection capabilites. The designed con-troller is applied as a plug-in module to a high density hard disk drive with a pre-existing conventional servo controller. Simulations have been carried out to demonstrate the effectiveness of this control scheme in the reduction of the periodic disturbances.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.11 no.5
• /
• pp.723-730
• /
• 2000

In this paper, we perform a performance analysis of serial acquisition scheme using AWGN rejection filter in Rayleigh fading channel and propose robust acquisition scheme using Reference filter, which is utilized to vary threshold at fading rate, in Rayleigh fading channel. AWGN rejection filter is utilized to evaluate running average for compensating channel gain. The JAKE model, which a channel model, is used for the analysis. The simulation result shows that the mean acquisition time of the proposed acquisition system is minimized than acquisition system using AWGN rejection filter and serial-search acquisition system.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.19 no.10
• /
• pp.2053-2063
• /
• 1994

Recently, there has been much interest in the terrestrial broadcasting of the HDTV signal. However, in the Simulcast where the NTSC and HDTV signal are transmitted using the same channel, the cochannel interference occurs which degrade the transmission performance. Recently, the GA(Grand Alliance) proposed the cochannel interference rejection system which use comb filter. However, this method shows poor performance for the NTSC carrier variation [7]. In this paper we propose a novel NTSC cochannel interference rejection system which shows improved performance for the NTSC carrier variation. In the proposed scheme, the adaptive notch filter is employed along with adaptive channel equalizer. In this paper, we also present some analytical results on the NTSC rejection performance of the GA and proposed scheme. Computer simulation results reveal that the proposed scheme outperforms order outperforms order of 10 in the BER(bit error rate) sense for the normal condition.

• IEIE Transactions on Smart Processing and Computing
• /
• v.4 no.3
• /
• pp.152-157
• /
• 2015

Various power supply noise sources in a system integrated circuit degrade the performance of a low dropout (LDO) regulator. In this paper, a capacitor-less low dropout regulator for enhanced power supply rejection is proposed to provide good power supply rejection (PSR) performance. The proposed scheme is implemented by an additional capacitor at a gate node of a pass transistor. Simulation results show that the PSR performance of the proposed LDO regulator depends on the capacitance value at the gate node of the pass transistor, that it can be maximized, and that it outperforms a conventional LDO regulator.

• Journal of Internet Computing and Services
• /
• v.2 no.3
• /
• pp.27-36
• /
• 2001

Recently much attention has been paid for interference mitigation technique for the COMA system, since more capacity is available with same bandwidth. In this paper, we introduces a novel adaptive interference suppression techniques for the CDMA system with narrow band interference. The proposed interference rejection scheme employs the adaptive linear prediction techniques in the subband. In each subband, we can more easily find and cancel the narrow band signal as compared to the full band. Thus, the proposed interference rejection can be classified as another time-frequency techniques for the narrow band interference rejection(10). Computer simulation is conducted for the 3-G COMA system with IF band sampling techniques, yielding better interference rejection and bit error rate performance as compared to conventional one. Also, optimum filter is analyzed and from the analysis, it can be shown the subband prediction techniques can suppress narrow band interference more efficiently.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1209-1212
• /
• 1996

In this paper, we design a stabilizing controller with disturbance rejection properties for multirate sampled-data systems which have periodic output measurement scheme. We assume that the plant is open-loop unstable and the disturbance consists of a sum of finite number of sine waves with different frequencies. A sufficient condition for maintaining observability in multirate sampled-data systems is derived. The proposed controller has an IMC structure and can be decomposed into the filtered-disturbance estimator and the inverse of the fast uniform sampled model of the pre-stabilized plant. An example is presented for illustrations.

• 제어로봇시스템학회:학술대회논문집
• /
• 1990.10b
• /
• pp.878-883
• /
• 1990

There have been many approaches to solve the disturbance rejection problem in the control of LTI systems with state independent disturbances or possibly nonlinear state dependent disturbances. From the view point of each actuator, robot manipulators can be modeled as the second class of systems. With this model, M.Nakao et al. [1] introduced a decentralized control scheme based on interference estimation which is simple in its implementation and robust to the coupled dynamics and parameter variations. This paper systematically generalizes the control scheme to arbitrary finite dimensional LTI systems with disturbances. In doing so, we develop a disturbance observer theory for solving the disturbance rejection problem. We also present a discrete version of the theory with discussion of sampling and time-delay effects.