• Title/Summary/Keyword: Range Error Reduction

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Study on Error Reduction in Dual Wavelength Digital Holography Using Modified Fine Map (수정된 화인 맵을 이용한 2-파장 홀로그래피와 잡음 제거 연구)

  • Yu, Young-Hun
    • Korean Journal of Optics and Photonics
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    • v.22 no.3
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    • pp.129-133
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    • 2011
  • Dual-wavelength holography has better axial range than single-wavelength holography, allowing unambiguous phase imaging but at the expense of increased noise. We have studied error reduction in dual wavelength holography using a modified fine map. The fine map is successful in measurement and has shown error reduction when the height of the object is less than the appled wavelength, but is unstable when the step height is larger than that wavelength. We have modified the fine map and we have found that the modified fine map was successful in measurement and error reduction even though the height of object was larger than the wavelength.

A Study on Course Correction Performance Expectation & Algorithm Implementation of 1D CCM (1D CCM 탄도수정 성능예측 및 알고리즘 구현 연구)

  • Kim, Ki-Pyo
    • Journal of the Korea Institute of Military Science and Technology
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    • v.10 no.1
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    • pp.5-13
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    • 2007
  • The trajectory of an current artillery munition is subject to a variety of different error sources resulting in more or less big deviation from the nominal predicted flight path. The 1D CCM(Course Correction Munition) has appeared to solve this problem and the mechanism of 1D CCM is a simple and low cost one using the influence of drag to range behavior of an artillery munition. In the paper 1D CCM concept has been simulated using wind tunnel experiment results of the specified Korean munition with CCF(Course Correction Fuze) and calculated the performance of its rang error reduction. From the simulated results it can be numerically explained that the possibility of adaptation of 1D CCM concept to Korean artillery munitions.

Performance Analysis of the UHF RFID Reader with the Range Correlation Effects of the Phase Noise (위상 잡음의 거리 상관 효과에 따른 UHF RFID 리더의 성능 분석)

  • Jang, Byung-Jun;Kang, Min-Soo;Lim, Jae-Bong
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.19 no.2
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    • pp.152-160
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    • 2008
  • In this paper, we analyze the performance of a direct-conversion UHF RFID reader with the range correlation effects of the phase noise. Since a UHF RFIB system uses the same oscillator to generate the transmitted carrier and the local oscillation, the periodic interference and phase noise reduction effects occur due to time delay between two signals. Through exact theory and simulation, we verify how to cancel the periodic interference phenomena using I/Q diversity combining technique. And, we analyze phase noise reduction effects due to range correlation as a function of the tag-reader distance and the offset frequency Using these results, we simulate the symbol-error-rate performance with respect to phase noise with and without range correation effects. We show that the phase noise of the local oscillator has little effect on the symbol-error-rate performance because of phase noise reduction by range correlation.

Improved Performance of Sensorless PMSM in Low Speed Range Using Variable Link Voltage (가변 링크전압에 의한 센서리스 PMSM의 저속운전 성능개선)

  • Lee, Dong-Hee;Kwon, Young-Ahn
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.49 no.10
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    • pp.708-711
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    • 2000
  • Sensorless PMSM is much studied for the industrial applications and home appliances because a mechanical sensor reduce reliability and increase cost. Most of sensorless algorithms are based on motor equations, and so the magnitude of phase voltage and current should be exactly obtained. However, the inverter output voltage applied to PMSM has relatively large error in the low speed range, and a relatively poor response is shown in the low speed range. This paper investigates the improved performance of sensorless PMSM in the low speed range. This paper proposes the error reduction of inverter output voltage which is realized through the variable link voltage. The proposed algorithm is verified through simulation and experiment.

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Sensorless Speed Control Algorithm of IPMSM for Wide Speed Range with an Improved Full-Order Flux Observer (향상된 전차원 자속 관측기를 이용한 매입형 영구자석 동기 전동기의 넓은 영역 센서리스 속도제어 알고리즘 기법)

  • Kang, Seong Yun;Yoon, Jae Seung;Shin, Hye Ung;Lee, Kyo-Beum
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.2
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    • pp.339-346
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    • 2017
  • This paper proposes a sensorless control method to improve the performance of an internal permanent magnet synchronous motor (IPMSM) control by using a full-order flux observer in a wide speed range. The conventional sensorless control method uses a constant gain for high performance at low-speed region. However, this method has drawbacks such as an increased angle error and current ripple in the high-speed region due to the fixed gain value. In order to overcome this problem, the gain of the full-order flux observer is changed by considering the angle error in the whole speed range. The proposed method minimizes the angle error for each region of the speed range by applying a relevant gain value, which improves the current ripple reduction and motor noise cancellation. The validity of proposed sensorless control method is verified by a simulation and an experiment.

Active vibration control of a flexible cantilever beam using Filtered-x LMS algorithm (Filtered-x LMS 알고리즘을 이용한 유연한 외팔보의 능동진동제어)

  • 박수홍;홍진석;김흥섭;오재응
    • Journal of the Korean Society for Precision Engineering
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    • v.14 no.3
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    • pp.107-113
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    • 1997
  • This paper presents the active control of a flexible cantilever beam vibration. The cantilever beam was excitied by a steady-state harmonic and white noise point force and the control was performed by one piezo ceramic actuator bonded to the surface of the beam. An adaptive controller based on filtered-x LMS algorithm was used and the controller was defined by minimizing the square of the response of error sensor. In the experiment, gap sensor was used as an error sensor while the sinusoidal or white noise was applied as a disturbance. In the case of sinusoidal input, more than 20 dB of vibration reduction was achieved over all range of the natural frequencies and it takes 5 seconds to control the vibration at first natural frequency and 1 second at other natural frequencies. In the case of white noise input, 7 dB of vibration reduction was achieved at the first natural frequency and good control performance was achieved in the considered whole frequency range. Results indicate that the vibration of a flexible cantilever beam could be controlled effectively when the piezo ceramic actuator was used with filtered-x LMS algorithm.

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Model Order Reduction Using Moment-Matching Method Based on Krylov Subspace and Its Application to FRF Calculation for Array-Type MEMS Resonators (Krylov 부공간에 근거한 모멘트일치법을 이용한 모델차수축소법 및 배열형 MEMS 공진기 주파수응답함수 계산에의 응용)

  • Han, Jeong-Sam;Ko, Jin-Hwan
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.436-441
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    • 2008
  • One of important factors in designing array-type MEMS resonators is obtaining a desired frequency response function (FRF) within a specific range. In this paper Krylov subspace-based model order reduction using moment-matching with non-zero expansion points is represented to calculate the FRF of array-type resonators. By matching moments at a frequency around a specific range of the array-type resonators, required FRFs can be efficiently calculated with significantly reduced systems regardless of their operating frequencies. In addition, because of the characteristics of moment-matching method, a minimal order of reduced system with a specified accuracy can be determined through an error indicator using successive reduced models, which is very useful to automate the order reduction process and FRF calculation for structural optimization iterations.

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Optimal Selection of Master States for Order Reduction (동적시스템의 차수 줄임을 위한 주상태의 최적선택)

  • 오동호;박영진
    • Journal of KSNVE
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    • v.4 no.1
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    • pp.71-82
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    • 1994
  • We propose a systematic method to select the master states, which are retained in the reduced model after the order reduction process. The proposed method is based on the fact that the range space of right eigenvector matrix is spanned by orthogonal base vectors, and tries to keep the orthogonality of the submatrix of the base vector matrix as much as possible during the reduction process. To quentify the skewness of that submatrix, we define "Absolute Singularity Factor(ASF)" based on its singular values. While the degree of observability is concerned with estimation error of state vector and up to n'th order derivatives, ASF is related only to the minimum state estimation error. We can use ASF to evaluate the estimation performance of specific partial measurements compared with the best case in which all the state variables are identified based on the full measurements. A heuristic procedure to find suboptimal master states with reduced computational burden is also proposed. proposed.

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A POSITION TRACKING ALGORITHM WITH RADAR MEASUREMENT

  • Lim You-Chol;Ma Keun-Su;Lee Jae-Deuk
    • Bulletin of the Korean Space Science Society
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    • 2004.10b
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    • pp.332-336
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    • 2004
  • This paper describes the remote tracking algorithm using measurements (azimuth, elevation, and slant range) of the radar ground station. Kalman filter model for noise reduction of the measured information is first derived by linearizing with respect to angle, angular rate, range, and range rate. And then a tracking algorithm is introduced to calculate the position of the vehicle during in-flight. The simulation results show that the algorithm is practical and effective enough tracking position of the vehicle in considerably less error.

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Correlation Analysis of Stress to Industrial Safety Regulatory Compliance, Human Error and Job Satisfaction (산업안전규제 순응 스트레스, 인적오류, 직무만족도간의 연관성 분석)

  • Park, Yong-Houn;Baek, Jong-Bae
    • Journal of the Korean Society of Safety
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    • v.29 no.3
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    • pp.91-97
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    • 2014
  • This study aims to suggest a measure to reduce industrial accident and secure adaptation to the industrial safety regulation policies by empirically establishing the effects of stress from adaptation to the industrial safety regulation on the human error, one of direct causes of industrial accident to the target groups of the industrial safety regulation policies. This study as for content range examines the stress from adaptation to the industrial safety regulation, job satisfaction, human error, and as for spatial range, this study performed an empirical research on the workers of 24 companies located within Chungcheong region centers district among 153 companies nationwide that uses 7 chemicals by introducing PSM (process safety management) system of the Ministry of Employment & Labor as of January 2012. Based on these results and suggestions there are five(5) necessities to reduce industrial safety regulations adaptation stress and human error generation, first(1st) is the necessity of understanding influential factors to stress, second(2nd) is the necessity to customized vocational training, third(3rd) is improving enhance system of job satisfaction, forth(4th) is preparing stress-reduction program, and fifth(5th) is introducing on-site restrictive action of advanced country as politics items.