• 전기학회논문지
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• 제67권3호
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• pp.433-439
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• 2018

In this paper, a SDINS(strapdown inertial navigation system) rapid initial alignment technique with adaptive time delay compensation is proposed. The proposed method consists of two steps. In first step, misalignment and data latency are estimated by conducting pre-transfer alignment. Then, hybrid alignment is designed to rapidly find the misalignment changes induced by pyro-shock. To improve the performance of hybrid alignment, adaptive time delay compensation method is suggested. We verify the performance improvement of the proposed alignment scheme comparing with the conventional transfer alignment method by van test. The test result shows that the proposed alignment technique improves alignment performance.

• 한국정밀공학회지
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• 제21권10호
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• pp.42-49
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• 2004

Electrical discharge machining (EDM) is one of the most extensively used non-conventional material removal process. The recent trend in reducing the size of product has given micro EDM a significant amount of research attention. Micro EDM is capable of machining not only micro holes and micro shafts as small as a few micrometers in diameter but also complex three dimensional micro cavities. But, longitudinal tool wear by electrical discharge is indispensable and this affects the machining accuracy in micro EDM process. Therefore, newly developed tool wear compensation strategy called round trip method is suggested and verified by experiment. In this method, machining depth of cut, overlap effect and critical travel length are also considered.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2005년도 춘계 학술대회 발표논문집
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• pp.49-52
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• 2005

Cepstral Mean Subtraction (CMS) makes effectively compensation for a channel distortion, but there are some shortcomings such as distortions of feature parameters, waiting for the whole speech sentence. By assuming that the silence parts have the channel characteristics, we consider the channel normalization using subtraction of cepstral means which are only obtained in the silence areas. If the considered techniques are successfully used for the channel compensation, the proposed method can be used for real time processing environments or time important areas. In the experiment result, however, the performance of our method is not good as CMS technique. From the analysis of the results, we found potentiality of the proposed method and will try to find the technique reducing the gap between CMS and ours method.

• 한국공작기계학회논문집
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• 제10권2호
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• pp.56-63
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• 2001

The objective of this research is to develop a measurement error compensation method for On-Machine Measurement (OMM) process based on a closed-loop configuration. Geometric errors of vertical machining center are measured using ball-bar system, and probing errors are measured using master ball. The errors are represented using homogeneous trans-formation matrices and the closed-loop configuration method is applied to calculate 3-dimensional errors. To verify the effectiveness of the method proposed in this research, compensated results are compared to the data using CMM process, and the results are analyzed. The results show the proposed method can be applied in OMM process to make the measured data more reliable.

• 정보저장시스템학회논문집
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• 제8권1호
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• pp.11-15
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• 2012

In this paper, we experimentally investigated compensation method of the mechanical errors for the micro holographic storage. The aim of this research was overcome of disc tilt and spherical aberration problems. The proposed method was performed by using glass plate and zoom optics.

• Journal of electromagnetic engineering and science
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• 제10권4호
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• pp.231-236
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• 2010

This study proposes a temperature compensation method of the complex permittivities of biological tissues and organs. The method is based on the temperature dependence of the Debye model of water, which has been thoroughly investigated. This method was applied to measured data at room temperature for whole blood, kidney cortex, bile, liver, and heart muscle. It is shown that our method can compensate for the Cole-Cole model using measured data at 20 $^{\circ}C$, given the Cole-Cole model based on measured data at 35 $^{\circ}C$, with a root-mean-squared deviation of 3~11 % and 2~6 % for the real and imaginary parts of the complex permittivities, respectively, among the measured tissues.

• Journal of Power Electronics
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• 제2권1호
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• pp.55-66
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• 2002

A new on-line dead-time compensation method for a permanent magnet (PM) synchronous motor drive is proposed. Using a simple disturbance observer without any additional circuit and off-line experimental measurement, disturbance voltages in the synchronous reference dq frame caused by the dead time and non-ideal switching characteristics of power devices are estimated in an on-line manner and fed to voltage references in order to compensate the dead-time effects. The proposed method is applied to a PM synchronous motor drive system and implemented by using software of a digital signal processor (DSP) TMS320C31. Simulations and experiments are carried out for this system and the results well demonstrate the effectiveness of the proposed method.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1352-1357
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• 2004

Thermal error compensation has been developed for CNC (Computer Numerical Control) machining center with moving heat sources. The thermal error in CNC machining center has an effect on machining accuracy more than the geometric error does. Thus, temperature distributions of a spindle unit have been analyzed numerically by a Finite Differential Method and experimentally by an infrared (IR) camera in this study. A multiple variable method has been derived to estimate the thermal deformation of the machine origin stably and effectively after measuring deformation and temperature data. The experimental results for a vertical machining center have shown that the thermal errors of the machine origins were reduced more than 30% by the developed method.

• 전기학회논문지
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• 제60권11호
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• pp.2049-2055
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• 2011

In this paper a new current control method is proposed for the discontinuous conduction mode of boost converter. The proposed method using a current gain feedforward compensation adjusts a measured inductor current value and then, calculated an average current precisely in the discontinuous conduction mode as well as continuous conduction mode. By applying the proposed method, the current measurement error is significantly reduced to 2% regardless of the operating points. The proposed method is analyzed and its performance is investigated in simulation. To verify the feasibility of the proposed scheme, a 10kW 3-phase interleaved boost converter was built and experimental results are matched to the simulation results.

• 한국음향학회지
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• 제13권5호
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• pp.40-50
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• 1994

본 논문에서는 3차원 음향 인텐시티 프로브의 고주파 영역에서 발생하는 감도 저하 현상을 보정하는 방법에 대해 연구하였다. 고주파 영역에서 측정오차는 음향 인텐시티 프로브를 구성하는 마이크로폰으로 수음한 신호들의 위상차로 인하여 발생한다. 이 오차는 마이크로폰 사이의 간격보다 측정대상 음향신호의 파장일 작을 경우, 즉 신호의 주파수가 높을수록 크게 발생한다. 이 연구에서는 두개의 마이크로폰으로 구성된 1차원 프로브의 보정법들을 제안하여 그 유효성을 컴퓨터 수치계산으로 검토하였다. 음향 인텐시티 프로브를 구성하는 마이크로폰 사이의 위상차를 음원의 추정된 방향으로 보정하는 방법이 가장 유용하였으며, 이를 3차원 프로브에 적용하여 임의의 방향으로 전파하는 음원에 대해 컴퓨터 수치계산으로 검증하였다. 그 결과, 4개의 마이크로폰을 60mm 간격으로 구성한 3차원 프로브로 1dB 이하의 정밀한 측정이 가능한 주파수 범위가 약 1.2kHz 이였던 것을 제안한 보정방법을 적용한 후, 약 2.8kHz까지 감도가 향상됨이 확인되어 제안한 보정법의 유효성이 증명되었다.