• Title/Summary/Keyword: signal model

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Adaptive Noise Suppression system based on Human Auditory Model (인간의 청각모델에 기초한 잡음환경에 적응된 잡음억압 시스템)

  • Choi, Jae-Seung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2008.05a
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    • pp.421-424
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    • 2008
  • This paper proposes an adaptive noise suppression system based on human auditory model to enhance speech signal that is degraded by various background noises. The proposed system detects voiced and unvoiced sections for each frame and implements the adaptive auditory process, then reduces the noise speech signal using neural network including amplitude component and phase component. Base on measuring signal-to-noise ratios, experiments confirm that the proposed system is effective for speech signal that is degraded by various noises.

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Functional Separation of Myoelectric Signal of Human Arm Movements Using Time Series Analysis (시계열 해석을 이용한 팔운동 근전신호의 기능분리)

  • 홍성우;남문현
    • The Transactions of the Korean Institute of Electrical Engineers
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    • v.41 no.9
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    • pp.1051-1059
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    • 1992
  • In this paper, two general methods using time-series analysis in the functional separation of the myoelectric signal of human arm movements are developed. Autocorrelation, covariance method and sequential least squares algorithm were used to determine the model parameters and the order of signal model to describe six arm movement patterns` the forearm flexion and extension, the wrist pronation and supination, rotation-in and rotation-out. The confidence interval to classify the functions of arm movement was defined by the mean and standard deviation of total squared error. With the error signals of autoregressive(AR) model, the result showed that the highest success rate was obtained in the case of 4th order, and success rate was decreased with increase of order. Autocorrelation was the method of choice for better success rate. This technique might be applied to biomedical and rehabilitation engineering.

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Controller Design by Error Shape and Steady-State Error Analysis for a Feed Drive System in CNC Milling Machine (CNC 밀링머신 이송장치의 오차유형 및 정상상태 오차해석에 의한 제어기 설계)

  • Lee Gun-Bok;Gil Hyeong-Gyeun
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.3 s.168
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    • pp.52-60
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    • 2005
  • This paper deals with the position control fur a feed drive system in CNC milling machine, which utilizes a modified error signal for the elimination of steady-state error. A linear time-invariant (LTI) system has consistent properties in response to standard test signal inputs. Those also appear in an error curve acquired from the response. From such properties, constructed is an error model for the position control of the feed drive. And then added is the output of the error model to the current error signal. Consequently the resulting proportional control system brings performance improvement in view of the steady-state error. The effectiveness of the proposed scheme is confirmed through simulations and experiments.

Identification of Dynamic Characteristics of Gimbals for Line-of-Sight Stabilization Using Signal Compression Method (신호 압축법을 이용한 시선안정화 제어용 짐벌의 동특성 규명)

  • Kim, Moon-Sik;Yoo, Gi-Sung;Yun, Jung-Joo;Lee, Min-Cheol
    • Journal of the Korean Society for Precision Engineering
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    • v.25 no.7
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    • pp.72-78
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    • 2008
  • The line-of-sight(LOS) stabilization system is a precision electro-mechanical gimbals assembly for suppressing vibration due to its environment and tracking the target in a desired direction. This paper describes the design of gimbals system to reject the disturbance and to improve stabilization. The controller consists of a DSP with transducer and actuator interfaces. Unknown parameters of the gimbals are estimated by the signal compression method. The cross-correlation coefficient between the impulse response from the assumed model and the one from model of the gimbals is used to obtain the better estimation. The quasi-impulse response through linear element included in the gimbals could be obtained by the signal compression method. The unknown parameter of the linear element could be estimated as comparing the bode plots for impulse response from gimbals with them from model's response.

Time-Domain Model of Surface Clutter for Airborne Phase-Array Radar (항공기 위상 배열 레이더에서 시간 영역의 지상클러터 생성 모델)

  • Kim, Tae-Hyung;Kim, Eun-Hee;Kim, Seon-Joo
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.24 no.7
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    • pp.730-736
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    • 2013
  • Time-domain clutter generation model for airborne pulse doppler phase-array radar is presented. Time-domain surface clutter signal is generated assuming earth of a sphere and considering geometry of a clutter patch, and generation of sub-array clutter signal is presented. The generated sub-array clutter signal can be used by simulation input signal in various radar applications of DBF(Digital Beamforming), ABF(Adaptive Beamforming), Stap(Space-Time Adaptive Processing) and etc.

Performance Analysis of Ultra Wide Band Systems in Indoor Wireless Channel (실내 무선 채널에서 초광대역 무선통신 시스템의 성능 분석)

  • Kim, Eun-Cheol;Woo, Sang-Kyu;Yang, Jae-Soo;Kim, Jin-Young
    • 한국정보통신설비학회:학술대회논문집
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    • 2008.08a
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    • pp.39-42
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    • 2008
  • In this paper, we analyze the performance of ultra wide band (UWB) systems in indoor wireless channel in accordance with the number of pulses per bit at transmit signals and the decision types of receiver. The indoor channel is modeled as the modified Saleh and Valenzuela (SV) model which has been proposed as a UWB channel model by the IEEE group, IEEE 802.15.SG3a. Two types of UWB signals are considered One is the pulse position modulation-time hopping (PPM-TH) signal. And the other is the pulse amplitude modulation-direct sequence (PAM-DS) signal. It is assumed that the receiver is an ideal receiver which can receive all signals of the multipath.

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Communication-Theoretic Analysis of Capture-Based Networks

  • Nguyen, Gam D.;Wieselthier, Jeffrey E.;Ephremides, Anthony
    • Journal of Communications and Networks
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    • v.14 no.3
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    • pp.243-251
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    • 2012
  • Under the power-based capture model, a transmission is successfully received at the destination, even in the presence of other transmissions and background noise, if the received signal-to-interference-plus-noise ratio exceeds a capture threshold. We evaluate the spectral efficiency of simple multi-user channels by combining the basic capture model with a communication-theoretic model. The result is a more refined capture model that incorporates key system design parameters (such as achievable bit rate, target bit error rate, channel bandwidth, and modulation signal constellations) that are absent from the basic capture model. The relationships among these parameters can serve as a tool for optimizing the network performance.

Functional Separation of Myoelectric Signal of Human Arm Movements using Autoregressive Model (자기회귀 모델을 이용한 팔 운동 근전신호의 기능분리)

  • 홍성우;손재현;서상민;이은철;이규영;남문현
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.4
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    • pp.76-84
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    • 1993
  • In this thesis, general method using autoregressive model in the functional separation of the myoelectric signal of human arm movements are suggested. Covariance method and sequential least squares algorithm were used to determine the model parameters and the order of signal model to describe six arm movement patterns` the forearm flexion and extension, the wrist pronation and supination, rotation-in and rotation out. The confidence interval to classify the functions of arm movement was defined by the mean and standard deviation of total squares error. With the error signals of autoregressive(AR) model, the result showed that the highest success, rate was abtained in the case of 4th order, and success rate was decreased with increase of order. This technique might be applied to biomedical-and rehabilitation-engi-neering.

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Small-Signal Model for Controlled On-Time Boost Power Factor Correction Circuit (연속-불연속 경계모드에서 동작하는 역률보상회로를 위한 소신호 모델)

  • Kang, Yong-Han;Seo, Bo-Hyeok
    • Proceedings of the KIEE Conference
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    • 1998.11a
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    • pp.141-143
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    • 1998
  • A new small-signal model for the controlled on-time boost Power factor correction (PFC) circuit is Presented. The proposed small-signal model is valid up to high frequencies ever 1kHz. IF to remove the low-frequency ripple from the output a 120Hz notch filter is used the proposed model can be used for the control design of the PFC circuit to improve the dynamics of the output voltage. The accuracy of the model is confirmed by comparing the experimental results with the simulational result.

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Dynamical Analysis of Cellular Signal Transduction Pathways with Nonlinear Systems Perspectives (비선형시스템 관점으로부터 세포 신호전달경로의 동역학 분석)

  • Kim Hyun-Woo;Cho Kwang-Hyun
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.12
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    • pp.1155-1163
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    • 2004
  • Extracellular signal-regulated kinase (ERK) signaling pathway is one of the mitogen-activated protein kinase (MAPK) signal transduction pathways. This pathway is known as pivotal in many signaling networks that govern proliferation, differentiation and cell survival. The ERK signaling pathway comprises positive and negative feedback loops, depending on whether the terminal kinase stimulates or inhibits the activation of the initial level. In this paper, we attempt to model the ERK pathway by considering both of the positive and negative feedback mechanisms based on Michaelis-Menten kinetics. In addition, we propose a fraction ratio model based on the mass action law. We first develop a mathematical model of the ERK pathway with fraction ratios. Secondly, we analyze the dynamical properties of the fraction ratio model based on simulation studies. Furthermore, we propose a concept of an inhibitor, catalyst, and substrate (ICS) controller which regulates the inhibitor, catalyst, and substrate concentrations of the ERK signal transduction pathway. The ICS controller can be designed through dynamical analysis of the ERK signaling transduction pathway within limited concentration ranges.