• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.1183-1186
• /
• 1998

Adaptive nois canceller can extract the noiseremoved spech in noisy speech signal by adapting the filter-coefficients to the background noise environment. A kind of LMS algorithm is one of the most popular adaptive algorithm for noise cancellation due to low complexity, good numerical property and the merit of easy implementation. However there is the matter of increasing misadjustment at voiced speech signal. Therefore the demanded speech signal may be extracted. In this paper, we propose a fast and noise robust wavelet packet adaptive noise canceller with NLMS-SUM method LMS combined algorithm. That is, we decompose the frequency of noisy speech signal at the base of the proposed analysis tree structure. NLMS algorithm in low frequency band can efficiently dliminate the effect of the low frequency noise and SUM method LMS algorithm at each high frequency band can remove the high frequency nosie. The proposed wavelet packet adaptive noise canceller is enhanced the more in SNR and according to Itakura-Satio(IS) distance, it is closer to the clean speech signal than any other previous adaptive noise canceller.

• Proceedings of the IEEK Conference
• /
• 1998.10a
• /
• pp.1049-1052
• /
• 1998

A new simplified circuit model for the switching noise analysis of the complicated multi-layer IC package is developed. The current flowing mechanism on the ground and power planes of the package is simplified by using the dependent current soures and partial plane circuit model. The methodology is very cost-efficient as well as accurate. It is demonstrated that the nosie based on the simplified circuit model has an excellent agreement with that of the complicated full circuit model. However, the simplified model takes only 5 minutes for the switching noise simulation, while the full circuit model takes more than 4 hours.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.8 no.1
• /
• pp.5-14
• /
• 2002

Objectives : In order to investigate industrial fatigue due to visual display terminal (VDT) work of post office. Methods : The questionnaire survey for subjective symptoms of fatigue was carried out on 39 post office clerks who had been engaged in VDT work for various length of work hours. The questionnaire comprised three groups of 10 items each, representing dullness and sleepiness, difficulty in concentration and bodily projection of fatigue. Results : The scores of dullness and sleepiness was 16.62, scores of concentration difficulty was 16.35, those of bodily fatigue was 16.23, and total scores was 49.21. Fatigue scores was significantly associated with age and work duration, VDT of work hours, ventilation, illumination, nosie. Conclusions : Data from this study support a statistically significant association between age and scores of dullness, scores of concentration difficulty, between work duration and scores of dullness, scores of bodily fatigue, between VDT of work hours and scores of bodily fatigue.

• Proceedings of the Korean Institute of Communication Sciences Conference
• /
• 1987.04a
• /
• pp.223-229
• /
• 1987

The error rate eqations of digital modulated signals transmitted through the fading cdannel have been derived in the Gaussian/Impulsive noise environments Whing the derived equations for the error drobadillties of ASK, QAM, FSK, MSK, PSK, and DPSK signais, the error tate performance of digital modulation systems have been evaluated and represented in the graghes as parameters of carrier to \ulcornernoise power ratio (CNR) and fading figures The results show that in the fading environenet the error is occurred more frequently by gaussian noise in the deep fading Howerer in the shallow fading lmpulsive noise is more domiant than gaussian nosie in occurring the error

• Journal of Astronomy and Space Sciences
• /
• v.12 no.1
• /
• pp.54-65
• /
• 1995

We present a design study for a remote sensing camera system which can be operated in multi-channel mode simultaneously with several bandpass filters. The camera control electronics is based on the multiplexed driving concept, which can provide a variety of flexibility for system control parameters and its individual optimisation. The design can also be applied to any system with linear sensors or frame sensors according to its functional requirements. The system design parameters have been examined, including modification of driving waveforms for different types of sensors, waveforms for low-nosie readout circuit in analog chain, and synchronisation with other signal processing.

• Proceedings of the KIEE Conference
• /
• 1987.07b
• /
• pp.1271-1275
• /
• 1987

With the stochastic process which consists of the harmonic sinusoid and the white nosie, the power spectrum of background EEG is estimated by the Pisarenko Harmonic Decomposition. The estimating results are examined and compared with the results from the maximum entropy spectral estimation, and the optimal order of this model can be determined from the eigen value's fluctuation of autocorrelation of background EEG. From the comparing results, this paper ensures that this method is possible to analyze the power spectrum of background EEG.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.614-619
• /
• 1997

The hydraulic pressure pulsation has on the effected on the acoustic nosie and control performance of the hydraulic-servo system. The Helmholtz attenuator introduction on the hydraulic line is an efficient device to reduce the hydraulic pulsation. The salient feature of causing hydraulic pulsation and the frequency characteristics of Helmholtz attenuator are studied. The hydraulic filter design parameters such as the locating position, connecting orifice area and accumulator volume are mathematically analyzed. The instrumental works are carried out with the remarkable reduction of the hydraulic pressure pulsation magnitude and the acoustic noise level.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2002.11a
• /
• pp.374.2-374
• /
• 2002

This paper investigates the insertion loss of nosie barrier with a intereference device. The efficiency of the conventional intereference-type noise barrier depends on specific frequency. Thus this study is performed to improve the efficiency of the rosie barrier in the range of broadband frequency, by changing the shape of intereference device and adding the channel with various depths. The boundary element method (BEM) is used to predict the insertion loss of noise barrier. (omitted)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2010.05a
• /
• pp.330-331
• /
• 2010

In this paper, BSR noise from an instrument panel of a vehicle are investigated with integrated experimental methods. First, potential source regions of the instrument panel for BSR are localized by using the module-excitor and near-acoustic field visualization system. Then, subjective evaluation of BSR nosie from the detected potential noise source regions is made with the Zwicker's loudness and time-varying loudness methods.

• Journal of Biomedical Engineering Research
• /
• v.8 no.1
• /
• pp.69-74
• /
• 1987

The power spectrum of background EEG is estimated by the Plsarenko Harmonic Decomposition with the stochastic process whlch consists of the nonhamonic sinus Bid and the white nosie. The estimation results are examined and compared with the results from the maximum entropy spectral extimation, and the optimal order of this from the maximum entropy spectral extimation, and the optimal order of this model can be determined from the eigen value's fluctuation of autocorrelation of background EEG. From the comparing results, this method is possible to estimate the power spectrum of background EEG.