• Title/Summary/Keyword: recursive system

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CTD Data Processing for CREAMS Expeditions: Thermal-lag Correction of Sea-Bird CTD

  • Kim, Kuh;Cho, Yang-Ki;Ossi, Hyong;Kim, Young-Gyu
    • Journal of the korean society of oceanography
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    • v.35 no.4
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    • pp.192-199
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    • 2000
  • Standard CTD data processing recommended by Sea-Bird Electronics produced thermal-lag corrections larger than 0.1 psu for the data taken during the CREAMS expeditions in the northern part of the East/Japan Sea where a vertical temperature gradient frequently exceeds 1.0$^{\circ}$C/m in the upper 100 m near the sea surface. As the standard processing is based upon a recursive filter which was introduced by Lueck and Pickle (1990), coefficients of the recursive filter have been newly derived for the CREAMS data by minimizing the difference between salinities of downcast and upcast in temperature-salinity domain. The new coefficients are validated by comparison with salinities measured by a salinometer, AUTOSAL 8400B. An accurate correction for the thermal-lag is critical in identifying water masses at intermediate depth in the East/japan Sea.

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Residual Synchronization Error Elimination in OFDM Baseband Receivers

  • Hu, Xingbo;Huang, Yumei;Hong, Zhiliang
    • ETRI Journal
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    • v.29 no.5
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    • pp.596-606
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    • 2007
  • It is well known that an OFDM receiver is vulnerable to synchronization errors. Despite fine estimations used in the initial acquisition, there are still residual synchronization errors. Though these errors are very small, they severely degrade the bit error rate (BER) performance. In this paper, we propose a residual error elimination scheme for the digital OFDM baseband receiver aiming to improve the overall BER performance. Three improvements on existing schemes are made: a pilot-aided recursive algorithm for joint estimation of the residual carrier frequency and sampling time offsets; a delay-based timing error correction technique, which smoothly adjusts the incoming data stream without resampling disturbance; and a decision-directed channel gain update algorithm based on recursive least-squares criterion, which offers faster convergence and smaller error than the least-mean-squares algorithms. Simulation results show that the proposed scheme works well in the multipath channel, and its performance is close to that of an OFDM system with perfect synchronization parameters.

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Mixture Filtering Approaches to Blind Equalization Based on Estimation of Time-Varying and Multi-Path Channels

  • Lim, Jaechan
    • Journal of Communications and Networks
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    • v.18 no.1
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    • pp.8-18
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    • 2016
  • In this paper, we propose a number of blind equalization approaches for time-varying andmulti-path channels. The approaches employ cost reference particle filter (CRPF) as the symbol estimator, and additionally employ either least mean squares algorithm, recursive least squares algorithm, or $H{\infty}$ filter (HF) as a channel estimator such that they are jointly employed for the strategy of "Rao-Blackwellization," or equally called "mixture filtering." The novel feature of the proposed approaches is that the blind equalization is performed based on direct channel estimation with unknown noise statistics of the received signals and channel state system while the channel is not directly estimated in the conventional method, and the noise information if known in similar Kalman mixture filtering approach. Simulation results show that the proposed approaches estimate the transmitted symbols and time-varying channel very effectively, and outperform the previously proposed approach which requires the noise information in its application.

Design of Speed Controller for Induction Motor With Inertia Variation (관성 변동을 갖는 유도전동기 속도 제어기 설계)

  • 신은철;김종선;공병구;유지윤;박내식;이준호
    • The Transactions of the Korean Institute of Power Electronics
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    • v.6 no.5
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    • pp.446-452
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    • 2001
  • In this paper, a novel design method of variable motor inertia in Induction motor drive system is proposed. The inertia of a load and a motor are estimated by using RLS (Recursive Least Square) algorithm. The speed controller is designed by Kharitonov theory of motor. The effectiveness of the proposed scheme is verified with simulation and experiment results.

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A Comparative Analysis of Online Update Techniques for Battery Model Parameters Considering Complexity and Estimation Accuracy (배터리 모델 파라미터의 온라인 업데이트 기술 복잡도와 추정 정확도 비교 및 분석)

  • Han, Hae-Chan;Noh, Tae-Won;Lee, Byoung-Kuk
    • The Transactions of the Korean Institute of Power Electronics
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    • v.24 no.4
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    • pp.286-293
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    • 2019
  • This study compares and analyzes online update techniques, which estimate the parameters of battery equivalent circuit models in real time. Online update techniques, which are based on extended Kalman filter and recursive least square methods, are constructed by considering the dynamic characteristics of batteries. The performance of the online update techniques is verified by simulation and experiments. Each online update technique is compared and analyzed in terms of complexity and accuracy to propose a suitable guide for selecting algorithms on various types of battery applications.

Development of Speed and Precision in the Mass Measurement of Moving Object (이송 물체의 질령 측정 속도 및 정밀도 향상 모사 연구)

  • Lee, Woo Gab;Chung, Jin Wan;Kim, Kwang Pyo
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.6
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    • pp.136-142
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    • 1994
  • This study presents an algorithm and related techniques which could satisfy the important properties of check weighers and conveyor scales. The algorithm of Recursive Least Squares Regression is described for te weighing system simulated as a dynamic model of the second order. Using the model and the algorithm, model parameters and then the mass being weighed can be determined from the step input. The performance of the algorithm is illustrated in digital simulation. Discussions are extended to the development of fast converging algorithm. It turns out that the algorithm shows several desirable features suitable for microcomputer assisted real-time signal processing, which are high precision and stability in noisy environment.

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A Queueing Model for Traffic Control in Leaky Bucket System (Leaky Bucket 시스템에서 트래픽제어에 관한 대기행렬모형)

  • 횡철희;이호우;윤승현;안부용;박노익
    • Journal of the Korean Operations Research and Management Science Society
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    • v.22 no.2
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    • pp.45-65
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    • 1997
  • We build a queueing model for buffered leaky bucket system. First, we set up system equations and them calculate the steady-state probabilities at an arbitrary time epoch by recursive method. We derive the mean waiting time and the mean number of cells in the input buffer, and evaluate the performance of the buffered leaky bucket system to find the optimal queue capacity and token generation rate that meet the quality of service(QoS).

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A Study of Boiler Control Loop Simulation in Thermal Power Plant (화력발전소 보일러 제어루프의 시뮬레이션에 관한 연구)

  • Lee, J.H.;Lee, C.J.
    • Proceedings of the KIEE Conference
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    • 1999.07b
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    • pp.868-870
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    • 1999
  • In this paper we obtain a discrete mathmatical model of a Boiler control system from expermental data, we find appropriate input signal and parameter estimation algorithm for identification of the Boiler control system in power plant. Under these conditions experimental data are collected from real system and parameters are estimated by the Recursive Least Square algorithm. The computer simulation results show the parameter estimation algorithm for identification and the effectiveness of controller design of the Boiler control system.

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ANALYSIS OF AN N DUPLICATE-SERVER SYSTEM (N개의 이중 서어버를 가진 시스팀의 해석)

  • Jeon, Gyeong-Pyo
    • ETRI Journal
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    • v.10 no.4
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    • pp.89-98
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    • 1988
  • We consider an N duplicate-server system, where each server consists of two reconfigurable duplicated units which are subject to breakdowns. This system is studied analytically using generating functions, and also numerically using the matrix-geometric procedure. Using the generating function approach we obtain a recursive expression of the queuelength distribution for N=1. This expression in difficult to generalize to N>1. The numerical method is applicable for any value of N. For any N, we also obtain the condition for stability and the availability of the system.

A FILTERING FOR DISCRETE MARKET SYSTEM WITH UNKNOWN PARAMETERS

  • Choi, Won
    • Journal of applied mathematics & informatics
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    • v.26 no.1_2
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    • pp.383-387
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    • 2008
  • The problem of recursive filtering for discrete market model with unknown parameters is considered. In this paper, we develop an effective filtering algorithm for discrete market systems with unknown parameters and the error covariance equation determining the accuracy of the proposed algorithm is derived.

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