• 방송공학회논문지
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• 제19권2호
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• pp.268-271
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• 2014

소스 부호 왜곡 모델 및 채널 유도 왜곡 모델 기반의 기존의 FEC 부호율 결정 기법들은 일반적으로 높은 계산 복잡도와 구현 비용을 요구하는 모델 파라메터 트레이닝 과정을 요구한다. 본 논문에서는 복잡한 모델링 과정을 피하기 위해서 최적의 FEC 부호율 결정을 위한 채널 손실 한계집합을 추정하기 위한 정확한 소스-채널 결합 왜곡 모델을 제안한다.

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.852-857
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• 2017

In this paper, measurements of ion mobility were performed in oxygen at gas pressures of 44.52 - 101.19 kPa using the drift tube method. Over this pressure range, mobility values were within the limits of 1.796 to $3.821cm^2{\cdot}V^{-1}{\cdot}s^{-1}$ were determined and ion mobility shown to decrease non-linearly with increasing gas pressure towards a certain level of saturation. Ion mobility measured in air was lower than that measured in oxygen at the same gas pressure. Finally, a parameter correction method for calibrating the relationship between the ion mobility and gas pressure in oxygen was proposed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.287-288
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• 2006

This paper introduces an approach of method to compensate accuracy error of diagonal direction. The measurement of squareness error is an important parameter in performance test of two axis Linear Motor and this exerts influence on accuracy error of diagonal test. However, previous knowledge management approaches are limited in deviation measurement of optical axis or restrictive elements of diagonal measurements using laser interferometer. But this proposed method calculated diagonal accuracy error which was occurred by squareness error and compensated squareness error using orthogonal correction method of PMAC. From this result, diagonal accuracy error is significantly reduced. This experimental results show that geometric error of squareness error is easily corrected by dynamic coordinate correction.

• Journal of Positioning, Navigation, and Timing
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• 제10권3호
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• pp.159-168
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• 2021

Precise Point Positioning-Real Time Kinematic (PPP-RTK) is an improved PPP method that provides the user receiver with satellite code and phase bias correction information in addition to the satellite orbit and clock, thus enabling single-receiver ambiguity resolution. Single station PPP-RTK concept is special case of PPP-RTK in that corrections are computed, instead of a network, by only one single GNSS receiver. This study is performed to experimentally verify the positioning accuracy performance of single baseline RTK level by a user who utilizes correction for a single station PPP-RTK using dual frequencies. As an experimental result, the horizontal and vertical 95% accuracy was 2.2 cm, 4.4 cm, respectively, which verify the same performance as the single baseline RTK.

• 핵의학기술
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• 제14권1호
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• pp.46-53
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• 2010

정적 영상 획득 시 기존의 정적 영상 획득 방식 대신 동적 영상 획득 방식을 이용하여 움직임에 의한 motion correction을 적용함으로써 정적 영상 획득 시 발생되는 움직임에 의한 문제점을 해결하고자 하였다. 실험은 capillary tube와 IEC body phantom을 이용하여 움직임이 없을 때 정적 영상 획득 방식으로 얻은 영상과 동적 영상 획득 방식으로 얻은 각각의 frame을 더한 영상에 대해 resolution, frequency, total counts, blind test를 비교 분석하였으며 임의로 최소한의 움직임과 과도한 움직임을 주어 motion correction 전후의 영상에 대해서도 resolution, frequency, total counts, blind test를 비교 분석 하였다. 기존의 정적 영상 획득 방식으로 얻은 영상과 동적 영상 획득 방식으로 얻은 각각의 frame을 더한 영상의 resolution, frequency, total counts, blind test의 결과 값의 차이가 없었다. 또한 최소한의 움직임과 과도한 움직임을 준 영상에 대해 motion correction 적용 전후의 비교 결과 값은 motion correction 후 resolution, frequency, blind test의 결과 값이 움직임이 없을 때의 정적 영상과 거의 차이가 없었다. 하지만 과도한 움직임에 대한 보정 시 frame당 흐림 현상이 많이 발생 하였으므로 좌표 보정이 어려워 frame을 제외하는 방법을 적용하였기 때문에 과도한 motion correction 후 삭제한 frame 수만큼 total counts에서 차이를 보였다. 정적 영상 획득 시 움직임이 예상되는 환자에게 기존의 정적 영상 획득방식이 아닌 동적 영상 획득 방식을 이용하여 움직임 발생시 좌표 보정과 흐림 현상이 심한 frame 제외 방법을 이용하여 정적 영상에서 움직임에 의해 발생되었던 영상의 질 저하와 정량적 분석의 신뢰도 감소, 재검사에 대한 문제점을 해결할 수 있을 것이라고 생각되며 motion correction에 제공되는 다양한 프로그램 개발과 임상 적용에 대한 광범위한 연구가 현실적으로 필요하며 향후 지속적인 연구가 기대되는 바이다.

• 전자공학회논문지B
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• 제33B권3호
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• pp.96-108
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• 1996

In this paper, we propose an object-oriented coding method in low bit-rate channels using block-based motion vectors and residual image compensation. First, we use a 2-stage algorithm for estimating motion parameters. In the first stage, coarse motion parameters are estimated by fitting block-based motion vectors and in the second stage, the estimated motion parametes are refined by the gradient method using an image reconstructed by motion vectors detected in the first stage. Local error of a 6-parameter model is compensted by blockwise motion parameter correction using residual image. Finally, model failure (MF) region is reconstructed by a fractal mapping method. Computer simulation resutls show that the proposed method gives better performance than the conventional ones in terms of th epeak signal to noise ratio (PSNR) and compression ratio (CR).

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 추계 학술발표회 3차
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• pp.31-36
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• 2010

This paper introduces a practical determination method for soil parameters adopted in the new performance based design code for port and harbour facilities in Japan. In the new port-design code, the depth profile of the derived values is modeled as the profile of the estimated values so as to be either the mean value or the regression line, then the correction factors are multiplied to the estimated value according to the coefficient of variation (if COV > 0.1) and the number of the data entries (if n < 10). The new port-design code is applied to the unconfined compression test results for the Hiroshima Port clay in order to evaluate the undrained shear strengths. From the discussion, it is emphasized that not only the statistic treatment but also the engineering judgment are required in the procedure of the soil parameter determination for the reliability design.

• Journal of Power Electronics
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• 제8권2호
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• pp.141-147
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• 2008

This paper deals with a new and improved control technique for shunt active filters (AF) used for compensating unwanted harmonic currents injected in the mains due to nonlinear varying loads. This work is motivated by the need to find a permanent solution to the rigorous hit and trial method for evaluating system parameters in an indirect control of AF. A fuzzy pre-compensated PI (Proportional-Integral) controller is used to fuzzify the reference DC voltage of AF to the controller input so that the overshoots and undershoots in its DC link voltage are minimized and the settling time is improved. A three-phase diode rectifier with R-L (Resistive-Inductive) load is used as a non-linear load to study the effectiveness of the proposed controller of the AF. Robustness to filter parameter variations, insensitivity to controller parameter variations, and transient response has been taken as performance evaluation parameters. The results are shown through simulations in Matlab using power system block sets to demonstrate the capability of the proposed controller of the AF.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1993년도 추계학술대회논문집; 반도아카데미, 26 Nov. 1993
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• pp.55-59
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• 1993

Interaction between system and disturbance results in system with time-dependent parameter. Parameter variation due to interaction has random characteristics. Most of the randomly varying parameters in control problem is regarded as white noise random process, which is not a realistic model. In real situation those random variation is colored noise random process. Modified F-P-K equation is proposed to get the response of the random parametric system using some correction factor. Proposed technique is employed to obtain the colored noise parametric system response and confirmed via Monte-Carlo Simulation.

• 전기전자학회논문지
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• 제25권2호
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• pp.261-266
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• 2021

이 논문에서는 환경 온도 변화를 고려한 열 적외선 데이터 보정 알고리즘을 설계하는 방법을 제시한다. 첫째, 열 적외선 측정 모델은 적외선 측정 데이터와 모델 환경 매개 변수 간의 관계를 사용하여 매개 변수 종속적인 1차 입력-출력 방정식으로 주어지고, 적외선 데이터에 대한 환경 온도의 영향을 보상하기 위해 보상 함수를 구한다. 실험을 통해 제안된 알고리즘이 적외선 데이터에 대한 환경 온도 변화의 영향을 효과적으로 보상할 수 있음을 보인다.