• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1995년도 추계학술대회논문집; 한국종합전시장, 24 Nov. 1995
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• pp.80-85
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• 1995

Too see the effects of finite record on the estimation of WVD in practice, a window which has time varying length is examined. Its length increases linearly with time in the first half of the record, and decreases from the center of the record. The bias error due to this window decreases inversely proportionally to the window length as time increases in the first half. In the second half, the bias error increases and the resolution decreases as time increases. The bias error due to the smoothing of WVD, which is obtained by two-dimensional convolution of the true WVD and the smoothing window, which has fixed lengths along time and frequency axes, is derived for arbitrary smoothing window function. In the case of using a Gaussian window as a smoothing window, the bias error is found to be expressed as an infinite summation of differential operators. It is demonstrated that the derived formula is well applicable to the continuous WVD, but when WVD has some discontinuities, it shows the trend of the error. This is a consequence of the assumption of the derivation, that is the continuity of WVD. For windows other than Gaussian window, the derived equation is shown to be well applicable for the prediction of the bias error.

• 대한전자공학회논문지SP
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• 제39권2호
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• pp.147-154
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• 2002

본 논문에서는 multimodal 특성을 갖는 데이터에 대하여 패턴 분류 시 Bhattacharyya distance에 기반한 에러 예측 기법을 제안한다. 제안한 방법은 multimodal 데이터에 대하여 분류 에러와 Bhattacharyya distance를 각각 실험적으로 구하고 이 둘 사이의 관계를 유추하여 에러의 예측 가능성을 조사한다. 본 논문에서는 분류 에러 및 Bhattacharyya distance를 구하기 위하여 multimodal 데이터의 확률 밀도 함수를 정규 분포 특성을 갖는 부클래스들의 조합으로 추정한다. 원격 탐사 데이터를 이용하여 실험한 결과, multimodal 데이터의 분류 에러와 Bhattacharyya distance 사이에 밀접한 관련이 있음이 확인되었으며, Bhattacharyya distance를 이용한 에러 예측 가능성을 보여주었다.

• Journal of applied mathematics & informatics
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• 제31권3_4호
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• pp.479-490
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• 2013

In this paper, we investigate a priori error estimates and superconvergence of varitional discretization for nonlinear parabolic optimal control problems with control constraints. The time discretization is based on the backward Euler method. The state and the adjoint state are approximated by piecewise linear functions and the control is not directly discretized. We derive a priori error estimates for the control and superconvergence between the numerical solution and elliptic projection for the state and the adjoint state and present a numerical example for illustrating our theoretical results.

• 제어로봇시스템학회논문지
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• 제7권11호
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• pp.953-957
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• 2001

This paper is concerned with a transfer alignment method for the SDINS under ship motions. Major error sources of transfer alignment are data transfer time-delay, lever-arm velocity and ship body flexure. Specifically, to reduce alignment errors induced by measurement time-delay effects, the error compensation method through delay state augmentation is suggested. A linearized error model for the velocity and attitude matching transfer alignment system is first derived by linearizing the nonliner measurement equation with respect to its time delay and augmenting the delay state into the conventional linear state equations. And then it is shown via observability analysis and computer simulations that the delay state can be estimated and compensated during ship motions resulting in considerably less alignment errors.

• 대한수학회보
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• 제51권3호
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• pp.717-737
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• 2014

We study the effect of numerical quadrature in space on semidiscrete and fully discrete piecewise linear finite element methods for parabolic interface problems. Optimal $L^2(L^2)$ and $L^2(H^1)$ error estimates are shown to hold for semidiscrete problem under suitable regularity of the true solution in whole domain. Further, fully discrete scheme based on backward Euler method has also analyzed and optimal $L^2(L^2)$ norm error estimate is established. The error estimates are obtained for fitted finite element discretization based on straight interface triangles.

• 대한수학회지
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• 제36권6호
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• pp.1033-1046
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• 1999

This paper is devoted to the point wise error estimate up to boundary for the standard finite element solution of Poisson equation with Dirichlet boundary condition. Our new approach used the discrete maximum principle for the discrete harmonic solution. once the mesh in our domain satisfies the $\beta$-condition defined by us, the discrete harmonic solution with dirichlet boundary condition has the discrete maximum principle and the pointwise error should be bounded by L-errors newly obtained.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.888-893
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• 2005

Since inertial sensor errors which increase with time are caused by initial orientation error and sensor errors(accelerometer bias and gyro drift bias), the accuracy of these devices, while still improving, is not adequate for many of today's high-precision, long-duration sea, aircraft, and long-range flight missions. This paper presents a navigation error compensation scheme for Strap-Down Inertial Navigation System(SDINS) using star tracker. To be specific, SDINS error model and measurement equation are derived, and Kalman filter is implemented. Simulation results show the boundedness of position and attitude errors.

• 한국통신학회논문지
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• 제7권4호
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• pp.167-172
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• 1982

동일 채널 간섭 및 임펄스 잡음 환경하에서 QAM 시스템의 특성을 오율의 관점에서 연구했다. 반송파대 잡음전력비, 반송파대 간섭파 전력비, 임펄스 지수 및 신호와 간섭파 간의 위상차의 함수로써 나타낸 L-level QAM신호의 오율식을 도출하여 16-QAM에 대한 수치계산을 하여 오율특성을 그래프로 보였다.

• 한국통신학회논문지
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• 제18권4호
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• pp.530-536
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• 1993

적응안테나에서는 최근 Gooch에 의하여 방정식 오차 방법을 이용한 새로운 적응 시스템이 제시 되었다. 그러나 이 방법에서는 pole부에 대한 역모델이 필히 요구되며 이로 인하여 안정성을 보장 받지 못한다. 본 논문에서는 Popov의 초안정성 이론을 바탕으로 새로운 알고리즘을 제안하였다. 또한 출력오차방법의 적응 시스템도 개발하였다. 제안한 알고리즘을 출력오차방법의 시스템에 적응하여 Gooch의 결과와 비교 검토하였다.

• 한국공작기계학회논문집
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• 제17권1호
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• pp.106-112
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• 2008

In this paper, It does the profile measurement of the cam of diesel engine SOHC of the actual object. It uses the measurement of run-out method. This method is that the surface of the object is measured by the sensor when the object rotate, and calculated and displayed by the computer the signal which acquired by sensor. When we acquire the signals, we have two error because of motion and contacting between cam and probe. In this paper, we compensate the motion error while simply liner equation. And we have a solution that we change the figure of probe when we have a contacting error. We compared the data measuring on developed automatic cam profile measuring system with the data measured on CMM.