• Title/Summary/Keyword: fixed bias

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A Study on Delivery Accuracy Using the Correlation between Errors (오차간의 상관관계를 이용하는 체계명중률 예측에 관한 연구)

  • Kim, Hyun Soo;Kim, Gunin;Kang, Hwan Il
    • The Journal of the Convergence on Culture Technology
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    • v.4 no.3
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    • pp.299-303
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    • 2018
  • Generally, when predicting the accuracy of the anti-air artillery system, the error is classified as fixed bias, variable bias, and random error. Then the standard deviation on the target is expressed as the square root of the squared sum of each error value which comes from the random error and variable bias and in the case of fixed bias, the mean value is shifted as the sum of errors from the fixed bias. At this time, the variables indicating the displacement of the direction of azimuth and elevation direction with regard to the change of the unit value of each error are weighted. These errors are then used to predict the system's delivery accuracy through a normally distributed integral. This paper presents a method of predicting system accuracy by considering the correlation of errors. This approach shows that it helps to predict the delivery accuracy of the system, precisely.

Variable Bias Techniques for High Efficiency Power Amplifier Design (고효율 전력증폭기 설계를 위한 가변 바이어스 기법)

  • Lee, Young-Min;Kim, Kyung-Min;Koo, Kyung-Heon
    • Journal of Advanced Navigation Technology
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    • v.13 no.3
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    • pp.358-364
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    • 2009
  • This paper shows some variable bias techniques which can improve the power added efficiency(PAE) for the designed power amplifier. Some simulations have been done to get the effect of the bias change, and variable bias is adopted to get the higher efficiency for dual mode amplifier which generates two different output power levels. With drain bias change and a fixed gate bias, the amplifier shows PAE improvement compared to the fixed bias amplifier. In addition, this paper analyzed nonlinear distortion of the power amplifier and has used the digital predistortion which can result in 10dB ACPR improvement for the dual band amplifier.

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High PAE Power Amplifier Using Adaptive Bias Control Circuit for Wireless Power Transmission (적응형 바이어스 조절 회로를 사용한 무선에너지 전송용 고효율 전력증폭기)

  • Hwang, Hyunwook;Seo, Chulhun
    • Journal of the Institute of Electronics and Information Engineers
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    • v.49 no.10
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    • pp.43-46
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    • 2012
  • In this paper, high efficiency power amplifier is implemented with high gain amplifier. Two-stage amplifier using adaptive bias control circuit improve efficiency at low input power. Fixed bias circuit and adaptive bias circuit both have about 76 % efficiency at maximum power level. However amplifier using an adaptive bias control circuit has 70 % at 6 dBm input power level when the amplifier using fixed bias circuit has 50%. The proposed power amplifier using the adaptive bias control circuit can have high efficiency at lower power level.

Design of the Dynamic Bias Control High-Efficiency Power Amplifier (동적 바이어스 조절 고효율 전력증폭기 설계)

  • 강종필;이세현;이경우;민이규;강경원;김동현;이상설;안광은
    • Proceedings of the IEEK Conference
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    • 2000.11a
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    • pp.317-320
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    • 2000
  • In this paper, a 0.5W, 2GHz high-efficiency class A power amplifier using the dynamic bias control is proposed. First of all, the drain bias control amplifier is analyzed theoretically and designed with commercial devices. Simulation results show that the proposed amplifier has a significant improved efficiency, compared to fixed bias power amplifier.

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The Study on the Application of Free Networks in Leveling (수준측양에 있어서 자유강조정법의 적용에 관한 연구)

  • 오창수
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.6 no.1
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    • pp.42-47
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    • 1988
  • In this study bias estimation method was applied to the free leveling networks adjustment by the concepts of free leveling networks. Optimum bias coefficients were determined by analizing the distribution of height errors with regard to bias coefficients. The object of this study lies in suggesting the utilities of free leveling networks adjustment, comparing one fixed-point and two fixed-points leveling networks adjustment.

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Suggestions to Improve Selection-Bias in Teaching or Studying Programs (교수 및 학습 프로그램 평가연구의 선별편향성 개선을 위한 제언)

  • Park, Kyoungho
    • Korean Medical Education Review
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    • v.12 no.1
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    • pp.3-8
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    • 2010
  • This study is designed to evaluate the effectiveness of teaching or studying programs, and thus to overcome the selectionbias in studies. Selection-bias derived from unobservable characteristics in the course of participants selection of the teaching or studying programs, in the case of cross-section data instrumental variable(IV) method and two stage least square estimation were suggested as an analysis tool. Panel data were analyzed by using both fixed effect in which individual effects are captured by intercept terms and random effect estimation where an unobserved effect can be characterized as being randomly drawn from a given distribution.

A performance improvement method in the gun fire control system compensating for measurement bias error of the target tracking sensor (표적추적센서의 측정 바이어스 오차 보상에 의한 사격통제장치 성능 향상 기법)

  • Kim, Jae-Hun;Lyou, Joon
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.2
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    • pp.121-130
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    • 2000
  • A practical method is proposed to improve hit probability of the digital gun fire control system, when the measured rate of the tracking sensor becomes biased under some operational situation. For ground moving target it is shown that the well-known Kalman filter which uses position measurement only can be optimally used to eliminate the rate bias error. On the other hand, for 3D moving aircraft we present a new algorithm which incorporate FIR-type filter, which uses position and rate measurement at the same time, and the fixed-lag smoother using position measurement only, and show that it has the optimal performance in terms of both estimation accuracy and response time.

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Biases in the Assessment of Left Ventricular Function by Compressed Sensing Cardiovascular Cine MRI

  • Yoon, Jong-Hyun;Kim, Pan-ki;Yang, Young-Joong;Park, Jinho;Choi, Byoung Wook;Ahn, Chang-Beom
    • Investigative Magnetic Resonance Imaging
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    • v.23 no.2
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    • pp.114-124
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    • 2019
  • Purpose: We investigate biases in the assessments of left ventricular function (LVF), by compressed sensing (CS)-cine magnetic resonance imaging (MRI). Materials and Methods: Cardiovascular cine images with short axis view, were obtained for 8 volunteers without CS. LVFs were assessed with subsampled data, with compression factors (CF) of 2, 3, 4, and 8. A semi-automatic segmentation program was used, for the assessment. The assessments by 3 CS methods (ITSC, FOCUSS, and view sharing (VS)), were compared to those without CS. Bland-Altman analysis and paired t-test were used, for comparison. In addition, real-time CS-cine imaging was also performed, with CF of 2, 3, 4, and 8 for the same volunteers. Assessments of LVF were similarly made, for CS data. A fixed compensation technique is suggested, to reduce the bias. Results: The assessment of LVF by CS-cine, includes bias and random noise. Bias appeared much larger than random noise. Median of end-diastolic volume (EDV) with CS-cine (ITSC or FOCUSS) appeared -1.4% to -7.1% smaller, compared to that of standard cine, depending on CF from (2 to 8). End-systolic volume (ESV) appeared +1.6% to +14.3% larger, stroke volume (SV), -2.4% to -16.4% smaller, and ejection fraction (EF), -1.1% to -9.2% smaller, with P < 0.05. Bias was reduced from -5.6% to -1.8% for EF, by compensation applied to real-time CS-cine (CF = 8). Conclusion: Loss of temporal resolution by adopting missing data from nearby cardiac frames, causes an underestimation for EDV, and an overestimation for ESV, resulting in underestimations for SV and EF. The bias is not random. Thus it should be removed or reduced for better diagnosis. A fixed compensation is suggested, to reduce bias in the assessment of LVF.

Optimal Minimum Bias Designs for Model Discrimination

  • Park, Joong-Yang
    • Communications for Statistical Applications and Methods
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    • v.5 no.2
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    • pp.339-351
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    • 1998
  • Designs for discriminating between two linear regression models are studied under $\Lambda$-type optimalities maximizing the measure for the lack of fit for the designs with fixed model inadequacy. The problem of selecting an appropriate $\Lambda$-type optimalities is shown to be closely related to the estimation method. $\Lambda$-type optimalities for the least squares and minimum bias estimation methods are considered. The minimum bias designs are suggested for the designs invariant with respect to the two estimation methods. First order minimum bias designs optimal under $\Lambda$-type optimalities are then derived. Finally for the case where the lack of fit test is significant, an approach to the construction of a second order design accommodating the optimal first order minimum bias design is illustrated.

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Bias Compensation Algorithm of Acceleration Sensor on Galloping Measurement System

  • Kim, Hwan-Seong;Byung, Gi-Sig;So, Sang-Gyun
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.127.6-127
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    • 2001
  • In this paper, we deal with two bias compensation algorithms of acceleration sensor for measuring the galloping on power transmission line. Firstly, the block diagram of galloping measurement system is given and a galloping model is presented. Secondly, two compensation algorithms, a simple compensation and a period compensation, are proposed. A simple compensation algorithm use the drafts of velocity and distance at fixed periods, so it is useful for constant bias case. Next, a period compensation algorithm can compensate a periodic bias. This algorithm use the previous measured data and compensated data for constant period, where the period is obtained by FFT method. Lastly, the effectiveness of proposed algorithms is verified by comparing between two algorithms in simulation, and its characteristics and the bias error bound are shown, respectively.

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