• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.893-900
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• 1998

본 논문에서는 잡음 예측 필터를 적용한 멀티 캐리어 CDMA 병렬 동기 시스템을 위한 임계치의 통계적인 해석에 중점을 둔다. 시스템 성능 척도로써 평균 동기 획득 시간을 검파 확률과 오보 확률의 관점에서 유도한다. 다중 경로 페이딩 채널에서 평균 동기 획득 시간을 유도한다. 수치해석 결과, 잡음 예측 필터를 적용한 멀티 캐리어 CDMA 병렬 동기 해석에 있어서 임계치의 통계적인 특성을 이용한 동기 해석이 임계치의 근사화에 의한 동기 해석보다 정확한 결과를 보임을 알 수 있다. 또한, 잡음 예측 필터를 적용한 멀티 캐리어 CDMA 별렬 동기 시스템이 넓은 범위의 SNR에 대해서 평균 동기 획득 시간을 최소화할 수 있는 임계치를 검파할 수 있음을 확인할 수 있다.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.7
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• pp.81-89
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• 1999

Image obtained by incomplete communication always include noise, blur and distortion, etc. In this paper, we propose and apply the new spatial filter algorithm, called an optimal adaptive generalized stack filter(AGSF), which optimizes adaptive generalized stack filter(AGSF) using neural network weight learning algorithm of back-propagation learning algorithm for improving noise removal and edge preservation rate. AGSF divides into two parts: generalized stack filter(GSF) and adaptive multistage median filter(AMMF), GSF improves the ability of stack filter algorithm and AMMF proposes the improved algorithm for reserving the sharp edge. Applied to neural network theory, the proposed algorithm improves the performance of the AGSF using two weight learning algorithms, such as the least mean absolute(LAM) and least mean square (LMS) algorithms. Simulation results of the proposed filter algorithm are presented and discussed.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.46 no.5
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• pp.1-13
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• 2009

Filter cache has been introduced as one solution of reducing cache power consumption. More than 50% of the power reduction results from the filter cache, whereas more than 20% of the performance is compromised. To minimize the performance degradation of the filter cache, the predictive filter cache has been proposed. In this paper, we review the previous filter cache predictors and analyze the problems of the solutions. As a result, we found main problems that cause prediction misses in previous filter cache schemes and, to resolve the problems, this paper proposes a new prediction policy. In our scheme, some reference bit entries, called MSBs, are inserted into filter cache and BTB, to adaptively control the filter cache access. In simulation parts, we use a modified SimpleScalar simulator with MiBench benchmark programs to verify the proposed filter cache. The simulation result shows in average 5% performance improvement, compared to previous ones.

• Information Systems Review
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• v.9 no.1
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• pp.85-103
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• 2007

The purpose of this study is to evaluate the performance of collaborative filtering recommender algorithms for better prediction accuracy of the customer's preference. The accuracy of customer's preference prediction is compared through the MAE of neighborhood based collaborative filtering algorithm and correspondence mean algorithm. It is analyzed by using MovieLens 1 Million dataset in order to experiment with the prediction accuracy of the algorithms. For similarity, weight used in both algorithms, commonly, Pearson's correlation coefficient and vector similarity which are used generally were utilized, and as a result of analysis, we show that the accuracy of the customer's preference prediction of correspondence mean algorithm is superior. Pearson's correlation coefficient and vector similarity used in two algorithms are calculated using the preference rating of two customers' co-rated movies, and it shows that similarity weight is overestimated, where the number of co-rated movies is small. Therefore, it is intended to increase the accuracy of customer's preference prediction through expanding the number of the existing co-rated movies.

• Journal of the Korea Society of Computer and Information
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• v.14 no.5
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• pp.45-54
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• 2009

In this paper, we propose an adult images detection algorithm using a mean intensity filter and an improved 2D Hough Transform. This paper is composed of three major steps including a training step, a recognition step, and a verification step. The training step generates a mean nipple variance filter that will be used for detecting nipple candidate regions in the recognition step. To make the mean variance filter, we converts an input color image into a gray scale image and normalize it, and make an average intensity filter for nipple areas. The recognition step first extracts edge images and finds connected components, and decides nipple candidate regions by considering the ratio of width and height of a connected component. It then decides final nipple candidates by calculating the similarity between the learned nipple average intensity filter and the nipple candidate areas. Also, it detects breast lines of an input image through the improved 2D Hough transform. The verification step detects breast areas and identifies adult images by considering the relations between nipple candidate regions and locations of breast lines.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.169-169
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• 2010

650nm 적외선 차단 필터를 Macleod 프로그램을 이용하여 설계하고, 이온보조증착(IAD) 장비를 이용하여 코팅한 후 투과도, 파장, 두께특성을 조사하였다. 차단필터의 증착물질은 $TiO_2$ (n=2.30) /$SiO_2$ (n=1.46) 을 사용하여 45층의 다층 박막으로 증착하였다. 코팅된 차단필터는 차단파장이 651 nm로써 평균 ${\pm}5$ nm 이내의 편차를 보였다. 420~630 nm 파장영역에서 평균 투과도는 89%이었으며, 투과도의 균일도는 약 2.12로써 매우 균일하였다. 투과도기 단파장 영역에서 감소된 것은 다층박막 증착 시 산소가 결핍된 것으로 판단된다.

• The Journal of the Korea institute of electronic communication sciences
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• v.16 no.4
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• pp.625-632
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• 2021

This paper studies the effect of the number of filters in the CNN (Convolutional Neural Network) layer on the performance of a noise attenuator. Speech is estimated from a noised speech signal using a 64-neuron, 16-kernel CNN filter and an error back-propagation algorithm. In this study, in order to verify the performance of the noise attenuator with respect to the number of filters, a program using Keras library was written and simulation was performed. As a result of simulation, it can be seen that this system has the smallest MSE (Mean Squared Error) and MAE (Mean Absolute Error) values when the number of filters is 16, and the performance is the lowest when there are 4 filters. And when there are more than 8 filters, it was shown that the MSE and MAE values do not differ significantly depending on the number of filters. From these results, it can be seen that about 8 or more filters must be used to express the characteristics of the speech signal.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.271-271
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• 2022

해수면의 변화를 분석하는 대표적인 방법 중 하나는 관측된 조위자료를 평균하여 평균해수면을 산정하고, 이를 이용하여 해수면의 상승 혹은 하강 추세를 파악하는 것이다. 평균해수면의 산정시 별도의 분석없이 단순한 산술평균만으로 평균해수면을 산정할 수 있어 해수면의 변화를 간편하게 추정할 수 있는 장점이 있으나, 관측된 조위자료는 천문조, 기상조 및 기후변화 등에 의한 변화가 모두 반영된 자료이기 때문에 장래의 해수면 변화를 정확하게 추정하기에는 어려움이 있다. 인위적인 개발이 없는 상태에서의 장기적인 해수면 변화는 주로 기후변화에 기인하기 때문에 미래의 변화를 정확하게 추정하기 위해서는 기후변화에 의한 해수면 변화, 즉 장주기 성분만을 고려한 분석이 수행되어야 정확한 미래 해수면 변화 산정이 가능하다(Kang et al., 2008; Pugh, 2004; Yang et al., 2002). 이에 본 연구에서는 관측된 조위자료에 저역통과필터(Low-pass filter)를 이용하여 천문조, 기상조 등의 단주기적 변동성을 제외하고, 장주기적 성분만을 고려한 평균해수면 변화 분석이 수행되었다. 분석결과, 산술평균으로 산정된 평균해수면의 상승경향에 비해 장주기적 성분만을 고려한 평균해수면 상승량이 더 큰 것으로 나타났다.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.955_956
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• 2009

계통의 전력품질을 향상시키기 위해서는 비선형부하로 인해 발생되는 무효전력을 보상해야 한다. 이러한 무효전력을 보상하는 알고리즘에서 지령치를 생성하기 위해 평균전력 또는 순시전력을 이용한다. 평균전력을 이용하는 방법은 매 한주기마다 평균전력을 계산하여 지령치를 생성하는 방법으로 필연적으로 지연시간이 발생하게 된다. 이에 반해 순시전력을 이용하는 방법은 매 스위칭 순간에 무효전력을 보상할 수 있어 시스템 응답속도가 빠른 장점을 가진다. 또한 유효전력과 무효전력을 계산하기 위해 디지털 필터를 이용하게 되면 회로구성이 간편하고 제어가 용이한 장점이 있다. 본 논문에서는 계통의 전력품질을 개선시키기 위해 1개의 LPF(Low Pass Filter)와 2개의 곱셈블럭으로 구성되는 디지털 필터를 사용하였다. 이의 유용성을 확인하기 위해 단상 능동전력 필터(active power filter)에 적용하여 시뮬레이션을 수행하였다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.959-962
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• 2012

In the process of image acquisition, transmission and storage, image degradation occurs due to various reason, the mainly reason is noise. To restore basic methods used images of impulse noise pollution by SM, AF, CWMF. In this paper, using the modified filter to remove impulse noise. The method consists of detection and noise filtering of the noise signal. For a non-noise signal is intact, the noise signal is filtered according to the algorithm. And then through the simulation is compared with known basic methods, with PSNR as judged by reference.