• 대한토목학회논문집
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• 제12권4_1호
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• pp.121-128
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• 1992

본 연구는 SPOT 위성영상에서 존재하는 정오차요소를 조정체계에 유의한 부가매개변수를 도입하여 보정하는 자체검정 광속조정의 알고리즘을 확립하고 SPOT 위성영상의 자료형태에 유의한 부가매개 변수항을 제시하는데 목적이 있다. 본 연구 결과, SPOT 위성영상용 자체검정 광속정법 알고리즘을 확립하고 프로그램을 개발하였으며, 부가매개변수의 결정력 검토 및 유의성검정을 통해 각 자료형태의 정오차 보정에 유의한 부가매개변수항을 결정할 수 있었다. 또한, 본 연구를 통해 확립된 SPOT 위성영상의 자체검정 광속조정 알고리즘은 위치결정의 정화도 향상에 유용함을 알 수 있었다.

• 디지털산업정보학회논문지
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• 제9권4호
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• pp.51-57
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• 2013

Research on calibration of array antenna has become a hot spot in the area of signal processing and it is necessary to obtain the phase mismatch of each antenna channel. This paper presents a new calibration method for an array antenna system. In order to calibrate the phase mismatch of each antenna channel, we used primary synchronization signal (PSS) which exists in LTE downlink frame. Primary synchronization signal (PSS) is based on a Zadoff-Chu sequence which has a good correlation characteristic. By using correlation calculation, we can extract primary synchronization signal (PSS). After extracting primary synchronization signal (PSS), we use it to calibrate and reduce the phase errors of each antenna channel. In order to verify the new array antenna calibration algorithm which is proposed in this paper, we have simulated the proposed algorithm by using MATLAB. The array antenna system consists of two antenna elements. The phase mismatch of first antenna and second antenna is calculated accurately by proposed algorithm in the experiment test. Theory analysis and MATLAB simulation results are shown to verify the calibration algorithm.

• 응용통계연구
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• 제23권4호
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• pp.759-765
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• 2010

In this paper, two new inverse regression methods are introduced. One is a distance based method, and the other is a likelihood based method. While a model is fitted by minimizing the sum of squared prediction errors of y's and x's in the classical and inverse methods, respectively. In the new distance based method, we simultaneously minimize the sum of both squared prediction errors. In the likelihood based method, we propose an inverse regression with Arnold-Beaver Skew Normal(ABSN) error distribution. Using the cross validation method with an asymmetric real data set, two new and two existing methods are studied based on the relative prediction bias(RBP) criteria.

• Journal of Electrical Engineering and Technology
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• 제2권3호
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• pp.401-407
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• 2007

Precise absolute measurement of the errors in a potential transformer (PT) can be achieved using high voltage capacitance bridge (HVCB) and capacitive divider. The uncertainty in a PT measurement using the HVCB system was evaluated by considering the overall factors affecting during the calibration of a PT. The expanded uncertainties are found to be not more than $30{\times}10^{-6}$ for ratio and $30{\mu}rad$ for phase up to the primary voltage of $V_p=22kV$. For same PTs, the measured errors in KRISS (Korea Research Institute of Standards and Science) using our bridge are well coincide with those in NMIA (National Measurement Institute of Australia) and PTB (Physikalisch-Technische Bundesanstalt) within the corresponding uncertainties.

• Journal of Information Processing Systems
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• 제13권1호
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• pp.83-94
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• 2017

Near-field source localization algorithms are very sensitive to sensor gain/phase response errors, and so it is important to calibrate the errors. We took into consideration the uniform linear array and are proposing a blind calibration algorithm that can estimate the directions-of-arrival and range parameters of incident signals and sensor gain/phase responses jointly, without the need for any reference source. They are estimated separately by using an iterative approach, but without the need for good initial guesses. The ambiguities in the estimations of 2-D electric angles and sensor gain/phase responses are also analyzed in this paper. We show that the ambiguities can be remedied by assuming that two sensor phase responses of the array have been previously calibrated. The behavior of the proposed method is illustrated through simulation experiments. The simulation results show that the convergent rate is fast and that the convergent precision is high.

• 천문학회보
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• 제41권1호
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• pp.74.2-74.2
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• 2016

It is important to know how well observation errors are removed in the calibration process prior to ensuing scientific research. In mm-VLBI observations, a radio wave suffers from an atmospheric propagation delay due to the rapid change of atmospheric refraction. It makes phases of VLBI correlation output fluctuate rapidly, which essentially decreases the coherence of phases and reduces the integration time. Consequently, it is challenging to achieve a high signal-to-noise ratio and enhance the quality of scientific output. Among the causes of the atmospheric propagation delay, water vapor in the troposphere is the most decisive factor to affect phase errors in the high frequency range (> 10GHz). It is expected to have the non-dispersive characteristic that enables to introduce new calibration strategy, Frequency Phase Transfer (FPT). This new method utilizes low frequency phases to compensate phase errors in high frequency bands. In addition, Korean VLBI Network (KVN) which benefits from the simultaneous 4-channels (22/43/86/129 GHz) observations is ideal to probe FPT performance. In order to evaluate FPT performance of KVN, we present the results of FPT phase analysis and discuss its performance.

• 한국생산제조학회지
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• 제8권2호
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• pp.108-115
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• 1999

This paper proposes the robot inverse calibration method using a neural networks. A highorder networks called Pi-Sigma networks has been used. The Pi-Sigma networks uses linear summing units in the hidden layer and product unit in output layer. The inverse calibration model which compensates the difference of joint variables only between measuring value and analytic value about the desired pose(position orientation) of a robot is proposed. The compensated values are determined by using the weights obtained from the learning process of the neural networks previously. To prove the reasonableness the SCARA type direct drive robot(4-DOF) and anthropomorphic robot(6-DOF) are simulated. It shows that the proposed calibration method can reduce the errors of the joint variables from $\pm$3 to $\pm$0.1.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.2435-2439
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• 2005

In case of visual sensing systems with multiple mirrors, systematic errors need to be reduced by the system calibration and the mirror position adjustment in order to enhance system measurement accuracy. In this paper, a self calibration method is presented for a visual sensing system designed to measure the three-dimensional information in deformable peg-in-hole tasks. It is composed of a CCD camera and a series of mirrors including two pyramidal mirrors. By using an image of the inner pyramidal mirror taken by the system, the error parameters of the inner pyramidal mirror could be calibrated or adjusted. Also the influence of the plane mirrors is investigated.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.177-180
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• 2001

This paper describes the calibration method and the evaluation method of relative expanded uncertainty for a multi-axis force/moment sensor. This sensor should be calibrated to be use in the industry. Now, the confidence of the calibration result is expressed with interference error. But it is no inaccurate, because an interference error, besides, a reproducibility error of the sensor, a error of this six-axis force/moment sensor calibrator, and so on. Thus, in order to accurately evaluate the relative expanded uncertainty of it, the concept of the uncertainty should be induced, and these errors must be contained in the relative expanded uncertainty. In this paper, the calibration method is exhibited and the evaluation method of the relative expanded uncertainty is also exhibited. And, a six-axis force/moment sensor was calibrated and the relative expanded uncertainty was evaluated.

• KIEE International Transactions on Electrophysics and Applications
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• 제5C권1호
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• pp.18-22
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• 2005

We developed a new systematic calibration procedure and applied it to the calibration of the diffusivity, segregation and TED model of the indium impurity. The TED of the indium impurity was studied under 4 different experimental conditions. Although the indium proved to be susceptible to the TED, the RTA was effective in suppressing the TED effect and in maintaining a steep retrograde profile. Just as in the case of boron, indium demonstrated significant oxidation-enhanced diffusion in silicon and its segregation coefficients at the Si/SiO₂ interface were significantly below 1. In contrast, the segregation coefficient of indium decreased as the temperature increased. The accuracy of the proposed technique has been validated by SIMS data and 0.13-㎛ device characteristics such as Vth and Idsat with errors less than 5% between simulation and experiment.