• Title/Summary/Keyword: Wave Transmission Analysis

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A Study on Noise Automatic Inspection System for Washing Machine Auto-Transmission (세탁기용 자동변속기 (Auto-Transmission)의 이상음 검사자동화 시스템에 관한 연구)

  • 김재열
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1998.03a
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    • pp.310-315
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    • 1998
  • This study includes noise automatic inspection system for washing machine auto-transmission one of modern home necessary. We effort to find and certificate sound noisesource by sound power and sound intensity, and apply to frequency analysis in vibration related sound noise. Still more we have been studying to data acquisition and programming for MS VisualBasic version 5.0. System component is below. 1) Pentium PC for data acquisition. 2) DSO for noise acquisition. 3) S/W for comparison and decision. 4) I/F Board for data communication. Wave form data through the DSO are converting to ASCII code data. The ASCII code through binary converting S/W are to be decision fitness or the badness comparison S/W. Finally, we will making noise monitoring system and automatic inspection system.

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A Study on Magnetic Field Distribution Characteristics for Remote Field Area (리모트 필드 영역에서의 자계 분포특성에 관한 연구)

  • Kim, S.K.;Lee, E.U.;Lim, S.S.;Kim, K.H.
    • Proceedings of the KIEE Conference
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    • 2000.11b
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    • pp.312-314
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    • 2000
  • The electric wave propagation characteristics of electromagnetic field by induction current shows a nonlinear distinction in the metal but linear on air. This paper is written about the magnetic transmission distinction in the metalic tube, which wrapped the center axis by the same direction. The electromagnetic field made by the transmission signal is transferred from the transmission coil area toward the receiving coil by the magnetic diffusion. So, it is different magnetic flux around the coil with one in the remote field area. Analyzing such a complex magnetic characteristic, we verified this theory by the vector analysis and presented eddy current mechanism and analytical model about magnetic distribution in the remote field area. This magnetic distribution rate in metal body will be very useful in the nondestructive inspection of the eddy current in remote field which is recently rising as a new technology.

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Influence of water content on dynamic mechanical properties of coal

  • Gu, Helong;Tao, Ming;Wang, Jingxiao;Jiang, Haibo;Li, Qiyue;Wang, Wen
    • Geomechanics and Engineering
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    • v.16 no.1
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    • pp.85-95
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    • 2018
  • Water affects the mechanical properties of coal and stress wave propagation. To comprehensively investigate the effect of water content on the properties of coal, laboratory tests including X-Ray Diffraction (XRD) analysis, P-wave test, S-wave test, static and dynamic compression test with different water contents were conducted. The compressive strength, elastic modulus and failure strain and their mechanism of coal specimen under coupled static-dynamic load with the increased water content were observed. Meanwhile, energy transmission and dissipation characteristics of a stress wave in coal specimens with different water contents under dynamic load and its relation with the failure features, such as fragmentation and fractal dimension, of coal was analyzed. Furthermore, the dynamic interpretation of water infusion to prevent coal burst based on water infusion model of coal seam roadway was provided.

A Study on mobile based EEG display and device development (모바일기반으로한 EEG표시 및 장치개발에 관한 연구)

  • Lee, Chung-Heon;Kim, Gyu-Dong;Hong, Jun-Eui;Kwon, Jang-Woo;Lee, Dong-Hoon
    • Proceedings of the IEEK Conference
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    • 2009.05a
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    • pp.145-147
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    • 2009
  • This research measures EEG signals which are generating on head skin and extracts brain concentration level related with brain activity. We have developed concentration wireless transmission system by displaying this EEG signal on PDA mobile device. The front head was used for measuring EEG signal and INA128 with TL084 and analog elements was used for measuring EEG signal, amplifying and filtering the signal. Measured analog EEG signals changed into digital signals by using ADC of PIC24FJ192 with 10bit resolution and 500Ks/s sampling rate. So The changed digital signals have transmitted to the PDA by using bluetooth. LabView 8.5 was also used for FFT transformation, frequency and spectrum analysis of the transferred EEG signal. As a result, $\alpha$ wave, $\beta$ wave, $\theta$ wave and $\delta$ wave were classified. we extracted the concentration index by adapting concentration extraction algorithm. This concentration index was transferred into PDA by wireless module and displaying.

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Preparation and Electromagnetic Properties of an Electromagnetic Wave Absorber

  • Sun, Chang;Sun, Kangning;Pang, Laixue;Liu, Jian
    • Journal of Magnetics
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    • v.21 no.1
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    • pp.61-64
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    • 2016
  • In this study, we report the as-prepared MgO-doped $BaFe_{12}O_{19}$, which was prepared by calcination technique and high-energy ball milling process, as an electromagnetic wave absorber. The phase analysis of $BaFe_{12}O_{19}$ and the as-prepared MgO-doped $BaFe_{12}O_{19}$ was detected utilizing X-ray Diffractometer (XRD). The microstructure was characterized using Scanning Electron Microscope (SEM). By means of the transmission/reflection coaxial line method, the electromagnetic properties and microwave absorbing properties of the as-prepared electromagnetic wave absorber were studied. It is found that the electromagnetic wave absorber has a minimum reflection loss value of -41 dB at 4.27 GHz with a matching thickness of 2.6 mm. The experiment results revealed that the as-prepared electromagnetic wave absorber could find potential applications in many military as well as commercial industries.

Computational Analysis of Mitigation of Shock wave using Water Column (액주를 이용한 충격파 완화에 대한 수치해석)

  • Jayabal, Rajasekar;Tae Ho, Kim;Heuy Dong, Kim
    • Journal of the Korean Society of Visualization
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    • v.20 no.3
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    • pp.49-57
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    • 2022
  • The interaction of planar shock wave with rectangular water column is investigated numerically. The flow phenomenon like reflection, transmission, cavitation, recirculation of shock wave, and large negative pressure due to expansion waves was discussed qualitatively and quantitatively. The numerical simulation was performed in a shock tube with a water column, and planar shock was initiated with a pressure ratio of 10. Three cases of the water column with different thicknesses, namely 0.5D, 1D, and 2D, were installed and studied. Water naturally has a higher acoustic impedance than air and mitigates the shock wave considerably. The numerical simulations were modelled using Eulerian and Volume of fluids multiphase models. The Eulerian model assumes the water as a finite structure and can visualize the shockwave propagation inside the water column. Through the volume of fluids model, the stages of breakup of the water column and mitigation effects of water were addressed. The numerical model was validated against the experimental results. The computational results show that the installation of a water column significantly impacts the mitigation of shock wave.

A Study on EEG based Concentration transmission and Brain Computer Interface Application (뇌파기반 집중도 전송 및 BCI 적용에 관한 연구)

  • Lee, Chung-Heon;Kwon, Jang-Woo;Kim, Gyu-Dong;Lee, Jun-Oh;Hong, Jun-Eui;Lee, Dong-Hoon
    • Proceedings of the KIEE Conference
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    • 2008.10b
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    • pp.155-156
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    • 2008
  • This research measures EEG signals which are generating on head skin and extracts brain concentration level related with brain activity. We develop concentration wireless transmission system for controlling hardware by using this signal. Two channels are used for measuring EEG signal on front head and Biopac system with MP-100 and EEG100C was used for measuring EEG signal, amplifying and filtering the signal. LabView 8.5 was also used for FFT transformation, frequency and spectrum analysis of the measure EEG signal. As a result, ${\alpha}$ wave, ${\beta}$ wave, ${\theta}$ wave and ${\delta}$ wave were classified. we extracted the concentration index by adapting concentration extraction algorithm. This concentration index was transferred into lego automobile device by wireless module and applied for BCI application.

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A Study on EEG based Concentration Transmission and Brain Computer Interface Application (뇌파기반 집중도 전송 및 BCI 적용에 관한 연구)

  • Lee, Chung-Heon;Kwon, Jang-Woo;Kim, Gyu-Dong;Hong, Jun-Eui;Shin, Dae-Seob;Lee, Dong-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.46 no.2
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    • pp.41-46
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    • 2009
  • This research measures EEG signals which are generating on head skin and extracts brain concentration level related with brain activity. We develop concentration wireless transmission system for controlling hardware by using this signal. Two channels are used for measuring EEG signal on front head and Biopac system with MP100 and EEG100C was used for measuring EEG signal, amplifying and filtering the signal. LabView 8.5 was also used for FFT transformation, frequency and spectrum analysis of the measured EEG signals. As a result, SMR wave, Mid-Bata wave, $\Theta$ wave classified. We extracted the concentration index by adapting concentration extraction algorithm. This concentration uldex was transferred into logo automobile device by wireless module and applied for BCI application.

Optimal Design of Fiber-optic Surface Plasmon Resonance Sensors

  • Jung, Jae-Hoon;Kim, Min-Wook
    • Journal of the Optical Society of Korea
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    • v.11 no.2
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    • pp.55-58
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    • 2007
  • We propose a systematic method for design of fiber-optic surface plasmon resonance (SPR) sensors. We used rigorous coupled wave analysis (RCWA) for analysis of the transmission spectrum, and the (1+1) evolution strategy (ES) was employed as an optimization tool. The simulation results show that the optimization method presented here is very useful in designing fiber-optic SPR sensor for strain and temperature measurement. This algorithm can be extended to another objective function with other weighting factors and optical parameters.

Analysis and Design Optimization of Interconnects for High-Speed LVDS Applications (고속 LVDS 응용을 위한 전송선 분석 및 설계 최적화)

  • Ryu, Jee-Youl;Noh, Seok-Ho
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.10
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    • pp.70-78
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    • 2009
  • This paper addresses the analysis and the design optimization of differential interconnects for high-speed Low-Voltage Differential Signaling (LVDS) applications. Thanks to the differential transmission and the low voltage swing, LVDS offers high data rates and improved noise immunity with significantly reduced power consumption in data communications, high-resolution display, and flat panel display. We present an improved model and new equations to reduce impedance mismatch and signal degradation in cascaded interconnects using optimization of interconnect design parameters such as trace width, trace height and trace space in differential printed circuit board (FPCB) transmission lines. We have carried out frequency-domain full-wave electromagnetic simulations, and time-domain transient simulations to evaluate the high-frequency characteristics of the differential FPCB interconnects. We believe that the proposed approach is very helpful to optimize high-speed differential FPCB interconnects for LVDS applications.