• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.439-442
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• 2006

본 논문에서는 IIR/FIR 필터 융합을 위한 기법을 제안하고 이를 INS/GPS 결합항법장치에 적용한다. IIR 형태의 EKF와 FIR 형태의 RHKF 필터를 각 필터의 잉여값과 잉여값 공분산을 이용한 적응형 융합 확률을 계산하여 융합함으로써 두 필터의 장점을 갖도록 한다. 이 융합 기법을 적용한 INS/GPS 결합항법장치는 기존의 단독 필터를 사용하는 것보다 강인한 특성을 갖고 항법정보를 제공한다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.35 no.8C
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• pp.697-708
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• 2010

In this paper, we compare the timing synchronization performance of the adaptive filter to that of the correlator in direct sequence spread spectrum (DS/SS) systems. The test variables used in the code synchronization are statistically analyzed for both schemes, and then the obtained results are used in calculating the detection and false alarm probabilities. Based on the derived probabilities, the synchronization performance is compared and the simulation is followed. Analysis and simulation results show that the correlator outperforms the adaptive filter under most synchronization environments.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.989-993
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• 2008

본 연구에서는 생체신호 중 비침습적으로 측정이 가능하고 많은 건강정보를 포함하고 있는 ECG(electrocardiogram)신호를 일상생활 중 보다 편리하게 모니터링 할 수 있는 시스템을 구현하고자 하였다. 이를 위하여 벨트형 ECG전극 시스템을 개발하였으며, 배터리로 구동 가능한 초소형 저전력 ECG측정시스템을 구현하였다. 또한 측정된 ECG신호의 무선전송을 위하여 Zigbee호환 무선센서노드를 이용하여 초저전력 무선데이터 통신부를 구성하였고 PC상에서 ECG신호를 모니터링하기 위한 프로그램을 구현하였다. 그리고 ECG측정 시 움직임에 따라 발생하는 동잡음의 제거를 위하여 이동평균필터(moving average filter)를 이용하여 기저선 변화를 추출하였고 이를 적응필터의 참조신호로 사용하여 동잡음을 제거하였다. 실험 결과 본 연구에 의해 구현된 ECG전극 및 계측시스템을 통해 활동상태 에서도 ECG계측 가능성을 확인하였으며, 제안한 적응신호처리기법을 통해 활동 중 ECG측정에서 동잡음의 최소화가 가능함을 확인하였다.

• Journal of Korea Multimedia Society
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• v.4 no.3
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• pp.222-229
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• 2001

Many techniques have been proposed for digital image enlargement, which use spatially neighbored pixels information in a still image. In this paper, we propose the digital image interpolation method that improves edge characteristics by selectively transposing the sub-windows of pseudomedian filter, which results in relatively better performance than others. We have simulated the proposed algorithm using Visual C++ and verified performance of the algorithm by PSNR(Peak signal Noise Ratio) and edge characteristics. Finally, we have designed the adaptive pseudomedian by using synopsys VHDL(Very high speed integrated circuit Hardware Description Language).

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.12
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• pp.1031-1043
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• 1990

A sequential recursive Kalman filtering algorithm, using causal image model, which is designed to operate in real time in the scanning mode is developed to enhance quality of 64Kbps videocodec images via function of suppression of various noises and optimum restoration. In order to improve its performance, adapted an averaging of pixel values between processing lines and adaptive filtering strategy based on the local spatial variance. Effecttiveness of the Kalman filtering algorithm proposed has been proved in the processed test kalman filtering algorithm proposed has been proved in the processed test images and the NMSE, LOGMSE measured, therefore, it may proposes possibility of the usage in videocodec for pre- and post- processing.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.7C
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• pp.688-695
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• 2003

In this paper, the parallel sub-filter searching structure to be adapted that divides a filter into several sub filters and the parameter decision technique to control adaptive parameters with power of received signal in the code acquisition system using adaptive filter are proposed. The numerical results for the system probabilities are derived that the code acquisition system using parallel sub-filter searching structure is statistically analyzed. Also, characteristic of the parameters in adaptive code acquisition system is analyzed by simulations and the parameter decision technique through SNRc estimation is explained. The system with parallel sub-filter searching structure outperforms by 1∼l.5 dB for 16 taps, 5∼6 dB for 64 taps. And the system with parameter decision technique works efficiently with the reasonable degree of degradation about 1 ∼2.5dB for 16 and 32 taps.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.8A
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• pp.1198-1205
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• 2000

In this paper, we introduce a modified interference cancellation scheme to overcome MAI in DS-CDMA. Among ICs(Interference Cancellers), PIC(Parallel IC) requires the more complexity, and SIC(Successive IC) faces the problems of the long delay time. Most of all, the adaptive detector achieves the good BER performance using the adaptive Inter conducted iteration algorithm. So it requires many iterations. To resolve the problems of them, we propose an improved adaptive detector that the received signal removed MAI through the sorting scheme and the cancellation method are fed into the adaptive filter. Because the improved input signal is fed into the adaptive filter, it has the same BER performance only using smaller iterations than the conventional adaptive detector, and the proposed detector having adaptive filter requires less complexity than the other detectors.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.2
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• pp.88-95
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• 1999

Stack filters are a class of digital nonlinear filters with excellent properties for signal restoration. Unfortunately, present algorithms for designing stack filters with large window size are limited in applications by their computational overhead and serial nature. In this paper, new, highly-parallel algorithm is developed for determining a stack filter which minimizes the mean absolute error criterion. It retains the iterative nature of the present adaptive algorithm, but significantly reduces the number of required to converge to an optima filter. A proof is also give that the proposed algorithm converges to an optimal stack filter.

• Proceedings of the Korean Information Science Society Conference
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• 2002.04b
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• pp.628-630
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• 2002

본 논문은 현재까지 제안된 여러 가지의 움직임 적응형 알고리즘을 비교 분석하였다. 비교 분석은 C++를 이용한 시뮬레이션을 하였고 여러 가지 이미지에 대잔 PSNR 값을 추출하였으며 에지 특성을 확인하고 그리고 시뮬레이션된 이미지를 원본과 비교 평가하였다. 그 결과 PSNR 값과 알고리즘의 성능과는 크게 낙관이 없었고, 에지 특성과 이미지간에 비교가 평가에 더 확실한 방법이었다. 알고리즘 성능은 어떤 이미지론 사용함에 따라 성능이 달라졌다. 전체적으로 볼 때 동영상에서는 $\Delta$- 형이 가장 좋은 결과가 확인되었으며 준동영상에서는 미디언 필터와 Adaptive형이 비슷한 성능을 보여 주었다.

• Proceedings of the Korea Contents Association Conference
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• 2008.05a
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• pp.614-621
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• 2008

With the proliferation of information and diversity of user environment, the filtering of information for providing suitable contents to user becomes more important. This paper represents the platform for user-context based contents service taking account of user's various environments. To make information more useful, web server devote their effort to select proper contents and reconstruct them according to the user preferences and environment condition. Finally we implement contents provider presenting personalized information for the prehistoric age in virtual museum on the web.