• Journal of the Korea Computer Industry Society
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• v.2 no.7
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• pp.997-1014
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• 2001

In this paper, we propose a method for dynamic selection of unrestricted motion vector(UMV) or default prediction mode(DPM) in H.263 bit stream. For this, we use the error of compensated image and the magnitude of motion vector. In the proposed strategy, the UMV mode is dynamically applied in a frame according to average magnitude of motion vector and error of compensated image. This scheme has improved the quality of image compared to the fixed mode UMV or DPM only. Number of searching points are greatly reduced when comparing to UMV. The Proposed method is more profitable to long video sequences having camera movement locally.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.1
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• pp.11-19
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• 2019

The waveguide slotted active phased array radar is characterized in that the beam is tilt in a specific direction when the feeding position of the antenna is not in the center of the antenna. If the beam deflection phenomenon is not properly compensated, error bias is generated in the target information collected by the radar, and the target accuracy is lowered. In this paper, we describe a technique to compensate the error of the target information that is collected in the active phased array radar of the waveguide slot type instead of the center of the antenna.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.27-33
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• 2011

For compensation of channel distortion from multipath fading and impulsive noise, a decision feedback equalizer (DFE) algorithm based on minimization of Error entropy (MEE) is proposed. The MEE criterion has not been studied for DFE structures and impulsive noise environments either. By minimizing the error entropy with respect to equalizer weight based on decision feedback structures, the proposed decision feedback algorithm has shown to have superior capability of residual intersymbol interference cancellation in simulation environments with severe multipath and impulsive noise.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.10a
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• pp.527-532
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• 1993

MascMC system is one of the MMC system module which performs measuring and checking of machined workpieces on the machine tools. Accuracy of the MascMC was compensated for developing a reliable measuring system by measurement error calibration. Reference gauges, ring gauges, block gauges,squares, spheres and cylindrical squares, were used for error identification and compensation. .+-. 10 .mu. m accuracy with 95% confidence interval was confirmed on the vertical and the horizontal machining center through the large number of experiments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.409-412
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• 2002

This paper presents a measurement method to compromise surface error in surface machining processes. In order to compromise the surface error in machining process, on-machine measurement is essential. There are two kinds of on-machine measurement methods available to measure the surface errors in flat workpieces: i.e., surface scanning method and sensor scanning method. However, motion errors are inevitably engaged in both methods. This paper proposes a new idea to measure the surface error for error compensation. The measurement system consists of a laser, a CCD camera and processing system, a carrier system with a stylus, and some optical units. The experimental results show that the proposed method is useful to compensate the surface errors of machined workpieces.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.399-404
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• 2002

Improvement of measuring accuracy is an essential part of quality control manufacturing process. The OMM is less than the CMM in measure accuracy but the OMM system is more efficient, easier to use than other measurement system. About 40~70% of the machine tool errors are induced by the thermal errors. Therefore, a key requirement for improving the measuring accuracy is to reduce the geometric and thermal errors. Thermal errors are measured by a ball bar system and predicted by the thermal error modeling. Furthermore, using the pre-defined thermal error map approach compensates the geometric accuracy of the OMM. Appropriate experiments are performed using ball-bar system, temperature measuring devices and touch-type probe. Compensated results are compared with those obtained using CMM to verify the proposed methods.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1147-1148
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• 2011

유도전동기의 가변속 구동시스템에서 자속축 기준제어를 이용하는 경향이 증가하고 있으며 설치환경, 가격 등의 제약으로 인하여 위치 및 속도센서가 없는 센서리스 속도제어가 많이 연구되고 있다. 대부분의 센서리스제어 방식에서 위치 및 속도추정은 전동기 전압방정식으로부터 계산된다. 따라서 파라미터 오차는 센서리스 제어성능에 큰 영향을 미치게 된다. 본 연구에서는 유도전동기의 속도 추정에서 파라미터 오차에 의해 발생하는 속도 오차를 배제하기 위하여 파라미터 보상을 가지는 상태관측기를 제안하고 종래의 방식과 비교하여 본 연구에서 제안한 방식을 검증한다.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.31-32
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• 2017

모듈형 멀티레벨 컨버터(Modular Multilevel Converter, MMC) 토플로지는 HVDC 송전을 위한 전력변환 시스템 또는 전기추진 선박과 같은 대용량 시스템에 주로 사용된다. 본 논문은 MMC 시스템의 출력 전류 센서에서 전류 검출 과정 시, 발생 가능한 오차 성분의 영향을 분석하였다. 또한 전류 센서의 오차 성분을 일반화 하고, 이를 시뮬레이션을 통해 타당성을 검증하였다.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.99-102
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• 2001

본 논문에서는 파라미터 불확실성이 유한한 로봇 매니퓰레이터에 대한 비선형 강인 제어기법을 제안한다. 파라미터의 불확실성을 보상하는 강인제어시 발생되는 정강 상태 오차를 개선시키기 위하여 오차 관련 함수에 추종오차의 적분항을 추가시키고 제어입력에 이 적분항이 포함되도록 한다. 설계된 제어시스템의 안정도는 Lyapunov 기법에 의하여 해석한다. 파라미터 불확실성을 가지는 로봇 매니퓰레이터에 대한 컴퓨터 시뮬레이션을 통하여 제안된 기법의 성능을 확인하고 5 링크 2 자 유도의 FARA 로봇에 대한 실험을 통하여 제안된 기법이 실용 로봇제어에 적용될 수 있음을 보이고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.5
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• pp.1597-1600
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• 2010

In this paper, a direct controller for nonlinear plants using a neural network is presented. The composed of the control input by using RBF neural networks and auxiliary input to compensate for effects of the approximation errors and disturbances. In the results, using this scheme, the output tracking error between the plant and the reference model can asymptotically converge to zero in the presence of bounded disturbances and approximation errors. Simulation results show that it is very effective and can realize a satisfactory control of the nonlinear system.