• Title/Summary/Keyword: high pass filter

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Motor noise removal for determining gait events over treadmill walking using wavelet filter

  • Yeom, Ho-Jun;Selgrade, Brian P.;Chang, Young-Hui;Kim, Jung-Lae
    • International journal of advanced smart convergence
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    • v.1 no.1
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    • pp.48-51
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    • 2012
  • The conventional method for filtering force plate data, low-pass filtering, does not always give accurate results when applied to force data from a custom-made, instrumented treadmill. Therefore, this study compares low-pass filtered data to the same data passed through a wavelet filter. We collected data with the treadmill running. However these include motor noise with ground reaction force at two force plates. We found that he proposed wavelet method eliminated motor noise to result in more accurate force plate data than the conventional low-pass filter, particularly at high speed motor operation. In this study we suggested the convolution wavelet (CNW) which was compared to that of a low-pass filter. The CNW showed better performance as compared to band-pass filtering particularly for low signal-to-noise ratios, and a lower computational load.

Layout of Long-pass-edge Filter Correspond with the Optical Transmission in Crystalline (수정체 광투과에 대응하는 LPE Filter 설계)

  • Kim, YongGeun
    • Journal of Korean Ophthalmic Optics Society
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    • v.4 no.2
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    • pp.57-63
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    • 1999
  • The optical absorption and transmittance of cow' crystalline were measured by spectrophotometer in the 200~800nm wavelength regions. The optical absorptions of crystalline composed of a high absorption band in the UV-A, UV-B, and appeared the light transmittance edge in the 400nm wavelength region, and completely transmitted without the absorption in the high wavelength regions than 400nm. Also, the optical absorption and transmittance had no temperature dependence. The optical transmittance spectrum of crystalline concord with the thin film structure of $n_0/(0.5H)L(LH)^6(0.5H)/n_s$ and $n_0{\mid}(0.5LH0.5L)^kL/1.25{\mid}4.0$ of long-pass edge filter form. In the artificial crystalline and inter lens layout, long-pass edge filter layout can UV cut off.

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A Study for the Effect of a Virtual Mass with a Low-Pass Filter on a Stability of a Haptic System (가상질량과 저주파통과필터에 의한 햅틱 시스템의 안정성 영역에 관한 연구)

  • Lee, Kyungno
    • Journal of Institute of Convergence Technology
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    • v.7 no.2
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    • pp.25-30
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    • 2017
  • This paper presents the effects of a virtual mass with a low-pass filter on the stability boundary of a virtual spring in the haptic system. In general, a haptic system consists of a haptic device, a sampler, a virtual impedance model and zero-order-hold. The virtual impedance is modeled as a virtual spring and a virtual mass. However the high-frequency noise due to the sampling time and the quantization error of sampled data may be generated when an acceleration is measured to compute the inertia force of the virtual mass. So a low-pass filter is needed to prevent the unstable behavior due to the high-frequency noise. A finite impulse response (FIR) filter is added to the measurement process of the acceleration and the effects on the haptic stability are simulated. According to the virtual mass with the FIR filter and the sampling time, the stability boundary of the virtual spring is analyzed through the simulation. The maximum available stiffness to guarantee the stable behavior is reduced, but simulation results still show that the stability boundary of the haptic system with the virtual mass is larger than that of the haptic system without the virtual mass.

Grid Pattern Segmentation Using High Pass Filter (고역통과 필터를 이용한 그리드 패턴 영역분할)

  • Joo, Ki-See
    • Journal of Advanced Navigation Technology
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    • v.11 no.1
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    • pp.59-63
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    • 2007
  • In this paper, an image segmentation algorithm is described to extract both the contour line and the inner grid patterns of body in case of ambiguous environment. The binary method using a threshold is used to extract image boundary. To reduce image noise, the $3{\times}3$ hybrid high pass filter adjusted for applying 3D information extraction of complicated shape object is proposed. This hybrid high pass filter algorithm can be applied to extract complicated shape object such as 3D body shape, CAD system, and factory automation since the processing time for image denoising is shorter than the conventional methods.

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KSLV-I FTS 수신기용 Tone Filter 설계

  • Hwang, Soo-Seul;Lim, You-Chol;Lee, Jae-Deuk
    • Aerospace Engineering and Technology
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    • v.3 no.2
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    • pp.104-115
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    • 2004
  • In this study, contains Design and Simulation data for Tone filter applied to the KSLV-1 FTS Receiver. Received Signal contains unwanted Noise and Jitter which should be eliminated by any kind of filters. In the design of KSLV-1 FTS Receiver, two different type of filters are used. One is Low-Pass Filter for rejecting high order harmonics and another is Tone Filter for sorting pure original signal in the mixed demodulate Signals. For the purpose of this development, various kinds of filter are studied and simulated for finding adequate type of filter.

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A Study on Series Arc Detection Using Band-pass Filters (대역통과필터를 이용한 직렬아크 검출에 관한 연구)

  • Kim, Il-Kwon;Kim, Jin-Su;Park, Keon-Woo;Kim, Kwang-Soon;Kim, Young-Il
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.1345-1347
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    • 2008
  • This paper described a method of determining whether arcing is present in a low-voltage wiring system. We simulated the series arcing that generated in electrical loads and fabricated a arc detection module which can discriminate between normal and arcing state. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage and an active band-pass filter with a frequency of 4 kHz ${\sim}$ 8 kHz to detect series arc signals only. We tested an Incandescent lamp that was controlled by a dimmer and analysed. The module consists of a high-pass filter with a low cut-off frequency of 3 kHz to attenuate power frequency voltage by 80 dB and an active band-pass filter with a frequency of 4 kHz to detect series arc signals only. From the experimental results, we could detect series arc signals without an influence of non-linear loads.

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A Study on the Seasonal Decomposition of the Railway Passenger Demand (철도수요의 시계열 분해 방법에 대한 연구)

  • 오석문;김동희
    • Proceedings of the KSR Conference
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    • 2001.10a
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    • pp.111-116
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    • 2001
  • This paper introduces how to adopt the X-12-ARIMA to decompose the railway passenger demand of the Korea National Railroad Especially, selecting on proper filters is focused. The trend filter is identical to the low pass filter in the signal Processing field, and so the seasonal filter is to band pass filter too. Some considerations, selecting a filter, are provided from the view-point of the spectrum analysis. The technique introduced in this paper will be adopted to the project that is to develope the forecasting system of Korea railway passenger demand which is a part of the high speed rail information system.

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An Enhanced Algorithm for an Optimal High-Frequency Emphasis Filter Based on Fuzzy Logic for Chest X-Ray Images

  • Shin, Choong-Ho;Lee, Jung-Jai;Jung, Chai-Yeoung
    • Journal of information and communication convergence engineering
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    • v.13 no.4
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    • pp.264-269
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    • 2015
  • The chest X-ray image cannot be focused in the same manner that optical lenses are and the resultant image generally tends to be slightly blurred. Therefore, the methods to improve the quality of chest X-ray image have been studied. In this paper, the inherent noises of the input images are suppressed by adding the Laplacian image to the original. First, the chest X-ray image using an Gaussian high pass filter and an optimal high frequency emphasis filter has shown improvements in the edges and contrast of flat areas. Second, using fuzzy logic_histogram equalization, each pixel of the chest X-ray image shows the normal distribution of intensities that are not overexposed. As a result, the proposed method has shown the enhanced edge and contrast of the images with the noise canceling effect.

Design and Fabrication of Diplexer using Lumped Elements (집중 소자를 이용한 다이플렉서 설계 및 제작)

  • Park, Yong-Wook
    • The Journal of the Korea institute of electronic communication sciences
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    • v.7 no.1
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    • pp.9-14
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    • 2012
  • In this study, the diplexer used a separator or a combine of signals was designed and its characteristics were investigated. The diplexer consists of two fixed tuned bandpass filter such as low pass filter(LPF) and high pass filter(HPF) sharing a common part and was simulated. The diplexer with micro-strip structure was fabricated. The LPF of diplexer has insertion loss of -0.4 dB, return loss of -30 dB and 1.6 GHz cut-off frequency and HPF has insertion loss of -0.8 dB, return loss of -30 dB and 1.9 GHz cut-off frequency, respectively.

A Target State Estimator Design to Improve the Gun Driving Command (포 구동명령 개선을 위한 표적상태 추정기 설계)

  • Lee, Seok-Jae;Kwak, Hwy-Kuen;Lyou, Joon
    • Journal of Institute of Control, Robotics and Systems
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    • v.13 no.11
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    • pp.1053-1059
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    • 2007
  • This paper presents a target sate estimator(TSE) with low pass filter for improving the gun driving command. The ballistic computer uses target information such as predicted range, velocity, acceleration of a target to generate the gun command. We adopt the finite impulse response(FIR) filter as our TSE to shorten calculation time for the driving command and due to its inherent stability property. We also introduce a post-processing filter to reduce the high frequency components in the output signal of a TSE which may cause instability of gun driving. The first order low pass filter has been designed based on $H{\infty}$ criteria considering the noise characteristics. To show the validity of the present scheme, simulation results are given for the overall gun driving system including aircraft target information.