• Title/Summary/Keyword: P-wave Noise

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Rock Mass Classification by Surface-borehole Hybrid Array Seismic Refraction Tomography in the Region of Serious Electrical Noises (전기적 잡음이 심한 지역에서 지표-시추공 복합배열 탄성파탐사에 의한 암반등급 산정)

  • Kim Ye Ryun;Sha Sang Ho;Nam Soon Sung;Jo Cheol Hyun;Cha Young Ho;Park Jong Bum;Shin Kyung Jin
    • Proceedings of the KSR Conference
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    • 2005.05a
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    • pp.610-614
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    • 2005
  • Rock mass classification by using electrical resistivity tomography(ERT) method is widely performed for the determination of rock support type in tunnel design. In the region of high electrical noise level, however, the result of the ERT will have many erroneous features. In this study, the back ground electrical noise had been measured to find out the reason why the results of ERT in this area did not agree to the expected geology confirmed by boreholes. In order to overcome this limitation of ERT, a hybrid surface-borehole array seismic refraction tomography had been followed. Using this technique, we could get P-wave velocity section including the depth level of tunnel. The comparison of the P-wave velocity and RMR shows fairly good statistical relationship to make it possible to set up the rock mass classification for the entire tunnel line.

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Removing Baseline Drift in ECG Signal using Morphology-pair Operation and median value (Morphology-pair 연산과 중간 값을 이용한 심전도 신호의 기저선 변동 잡음 제거)

  • Park, Kil-Houm;Kim, Jeong-Hong
    • Journal of the Korea Society of Computer and Information
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    • v.19 no.8
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    • pp.107-117
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    • 2014
  • This paper proposed the method of removing baseline drift by eliminating local maxima such as P, R, T-wave signal region and local minima Q, S-wave signal region. We applied morphology-pair operations improved from morphology operation to the ECG signal. To eliminate overshoot in the result of morphology-pair operation, we apply median value operation to the result of morphology-pair operation. We use MIT/BIH database to estimate the proposed algorithm. Experiment result show that proposed algorithm removing baseline drift effectively without orignal ECG signal distortion.

Application of the Onsite Earthquake Early Warning Technology Using the Seismic P-Wave in Korea (P파를 이용한 지진 현장 경보체계기술의 국내 적용)

  • Lee, Ho-Jun;Lee, Jin-Koo;Jeon, Inchan
    • Journal of the Society of Disaster Information
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    • v.14 no.4
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    • pp.440-449
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    • 2018
  • Purpose: This study aims to design and verify an onsite EEWS that extracts the P-wave from a single seismic station and deduce the PGV. Method: The P-wave properties of Pd, Pv, and Pa were calculated by using 12 seismic waveform data extracted from historic seismic records in Korea, and the PGVs were computed using empirical equation on the P properties - PGV relationship and compared with the observed values. Results: Comparison of the observed and estimated PGVs within the alarm level shows the error rate of 86.7% as minimum. By reducing the PTW to 2 seconds, the alarm time can be shortened by 1 second and the seismic blind zone near the epicenter can be shortened by 6 Km. Conclusion: Through this study, we confirmed the availability of the on-site EEWS in Korea. For practical use, it is necessary to develop regression formula and algorithm reflect local effect in Korea by increasing the number of seismic waveform data through continuous observation, and to eliminate the noise from the site.

Rat Magnetocardiograms Measured by YBCO SQUID Magnetometer (YBCO SQUID를 이용한 실험쥐의 심자도 측정)

  • Ahn, San;Kim, I.S.;Song, J.H.
    • Progress in Superconductivity
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    • v.12 no.2
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    • pp.124-128
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    • 2011
  • We have developed a high-$T_C$ SQUID magnetometer system to measure magnetocardiograms of laboratory rats. White noise of the measurement system was about 50 fT/$Hz^{1/2}$ when measured in a magnetically shielded box. We optimized the measurement position to obtain clear MCG wave from rat's small heart by using grid measurements. With the optimization, the MCG signal was successfully detected with the peak amplitude of about 50 pT. We could observe well defined P-, QRS-, and T-wave from the rat MCG. The results suggest that the developed system has a strong potential to monitor the progress of heart disease model using laboratory rat.

W-band Single-chip Receiver MMIC for FMCW Radar (FMCW 레이더용 W-대역 단일칩 수신기 MMIC)

  • Lee, Seokchul;Kim, Youngmin;Lee, Sangho;Lee, Kihong;Kim, Wansik;Jeong, Jinho;Kwon, Youngwoo
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.10
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    • pp.159-168
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    • 2012
  • In this paper, a W-band single-chip receiver MMIC for FMCW(Frequency-modulated continuous-wave) radar is presented using $0.15{\mu}m$ GaAs pHEMT technology. The receiver MMIC consists of a 4-stage low noise amplifier(LNA), a down-converting mixer and a 3-stage LO buffer amplifier. The LNA is designed to exhibit a low noise figure and high linearity. A resistive mixer is adopted as a down-converting mixer in order to obtain high linearity and low noise performance at low IF. An additional LO buffer amplifier is also demonstrated to reduce the required LO power of the W-band mixer. The fabricated W-band single-chip receiver MMIC shows an excellent performance such as a conversion gain of 6.2 dB, a noise figure of 5.0 dB and input 1-dB compression point($P_{1dB,in}$) of -12.8 dBm, at the RF frequency of $f_0$ GHz, LO input power of -1 dBm and IF frequency of 100 MHz.

The Effects of an Aerobics on the Auditory Evoked Potential (에어로빅스가 청각유발전위에 미치는 영향)

  • Park, Sang-Nam;Kim, Young-Hwal;Kim, Byung-Weon
    • Korean Journal of Clinical Laboratory Science
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    • v.38 no.3
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    • pp.224-230
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    • 2006
  • Up to now, there have been rare clinical studies on leaders and aerobics athletes. To get the useful data for protecting from auditory disorder, we selected 15 female aerobics leaders (experimental group) and 15 females (control group) unexperienced in aerobics and a without neurological and octolaryngological disorder. The average age was $34.87{\pm}8.80$ (experimental group) and $34.07{\pm}8.45$ (control group) years, and the average career of an aerobics leader (experimental group) was $8.33{\pm}4.73$ years. We measured the auditory evoked potential (AEP) of the two groups treated with 70, 75 and 85 dB intensity from January 2006 to May 2006 and analyzed the absolute latency (AL) and interpeak latency (IPL) by the SPSS/pc+ 12.0 program. In the comparison of the AL between the experimental group and the control group according to intensity, both ears treated with 70 and 75 dB had a significant difference (p<0.05) in the I, III, V wave and in the I, V wave respectively, and the experimental group treated with 85 dB showed a difference in the I, III, V wave (left ear) and in the I wave (right ear) respectively. The IPL of the two groups treated with various intensities had no prolongation. In the comparison of the AL between the experimental group and the control group according to ages, the experimental group in their 20s treated with 70 dB showed a significant difference (p<0.05) in the V wave (left ear) and in the I, III, V wave (right ear), and the experimental group in their 20s treated with 75 dB in the I, III wave (left ear) and in I, III, V wave (right ear), and experimental group in their 20s treated with 85 dB in the V wave (left ear) and in the III, V wave (right ear). The experimental group in their 30s treated with 70 dB had a significant difference (p<0.05) only in the V wave (right ear). Only in the IPL of subjects in their 20s treated with 85 dB, III-V and I-V of both ears was extended. In the comparison of the AL and IPL according to career, there was no significant difference between the two groups. From this results, we concluded that the lower sound intensity (70 dB) showed a more significant difference in the experimental group than the control group. We concluded that the leader of aerobics exposed to louder sounds than normal people are affected by auditory neurological and octolaryngological disorders. So we think that the leaders of aerobics need to control the noise level for protecting themselves against a disease.

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Application of a Fiber Fabry-Pérot Interferometer Sensor for Receiving SH-EMAT Signals (SH-EMAT의 신호 수신을 위한 광섬유 패브리-페롯 간섭계 센서의 적용)

  • Lee, Jin-Hyuk;Kim, Dae-Hyun;Park, Ik-Keun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.34 no.2
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    • pp.165-170
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    • 2014
  • Shear horizontal (SH) waves propagate as a type of plate wave in a thin sheet. The dispersion characteristics of SH waves can be used for signal analysis. Therefore, SH-waves are useful for monitoring the structural health of a thin-sheet-structure. An electromagnetic acoustic transducer (EMAT), which is a non-contact ultrasonic transducer, can generate SH-waves easily by varying the shape and array of magnets and coils. Therefore, an EMAT can be applied to an automated ultrasonic testing system for structural health monitoring. When used as a sensor, however, the EMAT has a weakness in that electromagnetic interference (EMI) noise can occur easily in the automated system because of motors and electric devices. Alternatively, a fiber optic sensor works well in the same environment with EMI noise because it uses a light signal instead of an electric signal. In this paper, a fiber Fabry-P$\acute{e}$rot interferometer (FFPI) was proposed as a sensor to receive the SH-waves generated by an EMAT. A simple test was performed to verify the performance of the FFPI sensor. It is thus shown that the FFPI can receive SH-wave signals clearly.

A Study on the Improvement of Occupants' Satisfaction for the Sound Environment When the Sound Source of Soundscape is Provided to the Interior Landscape (실내조경에 사운드스케이프 음원 제공시 재실자의 음환경 만족도 향상에 관한 연구)

  • Kim, Ho-Gon;Kook, Chan;Beak, Eun-Sun;Baek, Geon-Jong;Song, Min-Jeong;Shin, Hoon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.21 no.4
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    • pp.307-314
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    • 2011
  • This study was focused on the influence of soundscape provided to the interior landscape on the improvement of occupants' sound environment. When soundscape was provided to occupants together with the interior landscape rather than simply providing interior landscape, the occupants' satisfaction seemed to be improved. The most preferred sound source among the three sound sources was considered as the sound of the grasshopper. When both of the interior landscape and the landscape substances was provided, the adjectives with the average difference of more than 1 are "Vicissitudinous", "Elegant" and "Cheerful". When the interior landscape and the sound source were provided, such adjectives as "Vicissitudinous", "Complex" and "Cheerful" are extracted. When all the variables were provided, such adjectives as "Vicissitudinous", "Abundant" and "Cheerful" seem to show the difference of more than 1. Regarding "Vicissitudinous", it was possible to know that the average difference of more than 1.5 was the biggest. Regarding the relative values of the ${\alpha}$ wave and the ${\beta}$ wave for each part, it seemed that the highest ${\alpha}$ wave was generated on the left parietal lobe of P3, while the lowest ${\beta}$ wave was generated on the left and right frontal lobes of Fp1 and Fp2. According to this study, it was shown that the soundscape and the interior landscape seemed to influence the improvement of the occupants' sound environment.

A Study on the Measurement of Small Partial Discharges in a Low-voltage Induction Motor (저압 유도전동기에서 미소 부분방전 측정에 관한 연구)

  • Kil, Gyung-Suk;Song, Jae-Yong;Seo, Hwang-Dong;Hwang, Don-Ha;Kang, Dong-Sik;Kim, Yong-Joo
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.18 no.10
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    • pp.960-964
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    • 2005
  • In this paper, we dealt with a partial discharge(PD) measurement method that has been accepted as an effective and non-destructive technique to estimate insulation performance of low-voltage electric and electronic devices. The PD measurement system Is composed of a coupling network, a low noise amplifier, and associated electronics. h shielded box Is adopted to make a better measurement environment against around noise. A low cut-off frequency of the coupling network estimated by a sinusoidal wave input was 125 kHz (-3 dB). Calibration tests on laboratory set-up have shown that the PD measurement system has a stable sensitivity of 10 mV/pC. In an application test oil a low-voltage three phase Induction motor (5 HP), we could detect 0.53 pC level of partial discharge at the applied voltage of AC 650 $V_{peak}$.

An implementation of automated ECG interpretation algorithm and system(I) - Introduction of YECGA (심전도 자동 진단 알고리즘 및 장치 구현(I) - YECGA 개요)

  • Kweon, H.J.;Jeong, K.S.;Chung, S.J.;Choi, S.J.;Lee, M.H.
    • Proceedings of the KOSOMBE Conference
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    • v.1996 no.05
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    • pp.175-178
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    • 1996
  • The purpose of this thesis is the propose of various signal processing algorithm for the ECG(electrocardiogram) and the design of realtime automated ECG analyzer feasible with these algorithms. The algorithms are composed of (1)filtering procedure fer the estimation and removal of baseline drift, 60Hz power line interference, and muscle artifacts (2)detection procedure of QRS complex and P wave (3)typification procedure for the pattern classification according to the morphologies (4) selection of representative beat, significant point and wave boundary decision procedure and (5) parameter extraction and diagnosis procedure. All verifications are carried out between the algorithms proposed in this paper and other algorithms already proposed by many researchers, for the objective comparison in each procedure. The efficiency of proposed algorithms are demonstrated with the aid of internationally validated CSE database and the performances of filtering procedure are compared on artificial noise signal as well as actual ECG signals with appropriate noise components. for the comparison on the performance of designed automated ECG analyzer, the diagnosis results were compared with ECG analyzer manufactered by Fukuda denshi in Japan.

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