• Smart Media Journal
• /
• v.7 no.3
• /
• pp.9-15
• /
• 2018

This paper proposes an optimal gain modification method of the Multichannel Wiener filter (MWF) using speech presence probabilities. Conventional gain modification methods of MWFs have the problem of the increase of speech distortions while reducing residual noises with its relative heuristic approach. However, the proposed optimal gain modification method, derived by solving the unconstrained minimization problem of the probability-involved cost function, reduces amounts of residual noises and signal distortions simultaneously. Through an evaluation of the filtered waveforms and spectrograms, it is verified that the proposed method results in an improved SNR with less signal distortions compared to the conventional MWF.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.10 no.1
• /
• pp.14-21
• /
• 2007

This paper proposes SDINS(strapdown inertial navigation system) transfer alignment method for vertical launcher using an adaptive filter in the ship. First, the velocity and attitude matching transfer alignment method is designed to align SDINS for vertical launcher. Second, the adaptive filter is employed to estimate measurement noise variance in real time using the residual of measurements. Because it is difficult to decide measurement noise variance when noise properties of the ship SDINS are changed. To verify its performance, it is compared with the EKF(Extended Kalman filter) using uncorrect measurement variance. The monte carlo simulation results show that proposed method is more effective in estimating attitude angle than EKF.

• 제어로봇시스템학회:학술대회논문집
• /
• 2005.06a
• /
• pp.1500-1504
• /
• 2005

This paper proposes the design methodology of genetic algorithm (GA)-based fuzzy Kalman filter for tracking the maneuvering target. The performance of the standard Kalman Filter (SKF) has been degraded because mismatches between the modeled target dynamics and the actual target dynamics. To solve this problem, we use the method to estimate the increment of acceleration by a fuzzy system using the relation between maneuver filter residual and non-maneuvering one. To optimize the fuzzy system, a genetic algorithm (GA) is utilized and this is then tuned by the fuzzy logic correction. Finally, the tracking performance of the proposed method has been compared with those of the input estimation (IE) technique and the intelligent input estimation (IIE) through computer simulations.

• Proceedings of the Korean Institute of Intelligent Systems Conference
• /
• 2006.05a
• /
• pp.425-428
• /
• 2006

In this paper, we propose an interacting multiple model (IMM) method using intelligent tracking filter with fuzzy gain to reduce tracking errors for maneuvering targets. In the proposed filter, to exactly estimate for each sub-model, we propose the fuzzy gain based on the relation between the filter residual and its variation. To optimize each fuzzy system, we utilize the genetic algorithm (GA). Finally, the tracking performance of the proposed method is compared with those of the adaptive interacting multiple model (AIMM) method and input estimation (IE) method through computer simulations.

• Journal of Institute of Control, Robotics and Systems
• /
• v.5 no.8
• /
• pp.883-888
• /
• 1999

To obtain high positioning auccuracy for a long, flex bleman Ipulator, residual vibration must be removed from the tip motion. But it is difficult to control the vibration of low frequency. There are open-loop and closed loop methods in the elimination of the residual vibration. We inroduce input shaping technique has been used as a simple open-loop method of controlling the residual vibration of a flexible manipulator. Design of input shaper in the continuous time domain is complicated. This paper presents a new technique that designs input shaper in the z-domain and analyzes input shaping method in the z-domain. This technique is simple and easy to design input shaper.

• Journal of the Korean Vacuum Society
• /
• v.17 no.4
• /
• pp.262-269
• /
• 2008

The residual gas analyzer (RGA) is employed for the process control of a vacuum system by measuring residual gases in it. This review paper introduces operating principles of the RGA and problems that can be encountered during use, together with their possible solutions.

• The Journal of the Institute of Internet, Broadcasting and Communication
• /
• v.15 no.3
• /
• pp.99-105
• /
• 2015

This paper deals with the mMMA (modified MMA) which possible to improving the convergence speed that employing the serial connecting form of two stage digital filter instead of signal filter of MMA adaptive equalizer without applying the variable step size for compensates the intersymbol interference by channel distortion in the nonconstant modulus signal. The adaptive equalizer can be implemented by signal digital filter using the finite order tap delay line. In this paper, the equalizer is implemented by the two stage serial form and the filter coefficient are updated by the error signal using the same algorithm of MMA in each stage. The fast convergence speed is determined in the first stage, and the residual isi left at the output of first stage output is minimized in the second stage filter. The same digital filter length was considered in single stage and two stage system and the performance of these systems were compared. The performance index includes the output signal constellation, the residual isi and maximum distortion, MSE that is measure of the convergence characteristics, the SER. As a result of computer simulation, mMMA that has a FIR structure of two stage, has more good performance in every performance index except the constellation diagram due to equalization noise and improves the convergence speed about 1.5~1.8 time than the present MMA that has a FIR structure of single stage.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.25 no.2
• /
• pp.199-207
• /
• 2014

Although High-altitude electromagnetic pulse(HEMP) protection filter meets the requirements of pulsed current injection(PCI) acceptance test, the equipment under test which has low electromagnetic susceptibility level can be damaged during PCI verification test that is performed on operating condition of equipment. This paper proposed the HEMP effect analysis method using comparison of norms between residual current of HEMP filter and transient electromagnetic conducted susceptibility criteria of equipment, as an alternative method under the condition that performing PCI verification test is limited in HEMP hardened facilities. PCI acceptance test of HEMP filter, transient electromagnetic conducted susceptibility test, and PCI verification test are performed and test results are analyzed.

• Journal of Digital Contents Society
• /
• v.18 no.1
• /
• pp.141-147
• /
• 2017

Scalable extension of High Efficiency Video Coding (SHVC) standard uses the up-sampled residual data from the base layer to make a residual data in the enhancement layer. This paper describes an efficient algorithm for improving coding gain by using the filtered residual signal of base layer in the Scalable extension of High Efficiency Video Coding (SHVC). The proposed adaptive filter selection mechanism uses the smoothing and sharpening filters to enhance the quality of inter-layer prediction. Based on two filters and the existing up-sampling filter, a rate-distortion (RD)-cost fuction-based competitive scheme is proposed to get better quality of video. Experimental results showed that average BD-rate gains of 1.5%, 2.1%, and 1.7% for Y, U and V components, respectively, were achieved, compared with SHVC reference software 5.0, which is based on HEVC reference model (HM) 13.

• Journal of the Society of Naval Architects of Korea
• /
• v.30 no.4
• /
• pp.8-16
• /
• 1993

Auto-Pilot System uses heading angle information via the position sensor and the rudder device to control the ship direction. Most of the control logics are composed of the state estimation and control algorithms assuming that the measurement device and the actuator have no fault except the measurement noise. But such asumptions could bring the danger in real situation. For example, if the heading angle measuring device is out of order the control action based on those false position information could bring serious safety problem. In this study, the control system including improved method for processing the position information is applied to the Auto-Pilot System. To show the difference between general state estimator and F.D.F., BJDFs for the sensor and the actuator failure detection are designed and the performance are tested. And it is shown that bias error in sensor could be detected by state-augmented estimator. So the residual confined in the 2-dim in the presence of the sensor failure could be unidirectional in output space and bias sensor error is much easier to be detected.