• Journal of Korea Multimedia Society
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• v.15 no.9
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• pp.1086-1092
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• 2012

In this paper, we propose the rate control scheme reducing frame skipping at low bit-rate. As the method considering lossy parts in the compressing process at the existing scheme, the proposed scheme is improved by subtracting the converted bits from the target bit-rate of the current frame. The converted bits are the value resulted from multiplying the ratio of the current frame MAD to the previous frame MAD by the compressed bits changed from the remaining values after compressing the previous frame.

• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.4
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• pp.307-314
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• 2011

This study proposed detection method of Marine debris using unmanned aerial photography. For unmanned aerial photography, a RC(Radio Control) helicopter which has good movability and economics was used. To a camera mounting, a gimbal equipment was attached to the bottom of the RC helicopter. The gimbal equipment is very useful because it is not seriously affected by vibration and rolling. In addition, we invented that digital image processing algorithm using Matlab program for detection of marine debris from photographs. Particularly, background subtraction in invented algorithm was applied. As a result, marine debris of a variety of forms from different sand states of coast were reliably detected. In the future, monitoring using proposed method was expected to contribute that the solution to representative problem of monitoring area selecting and estimate the total litter mass over the beach. Moreover, It is considered a greater application possibility to marine environmental observations.

• Proceedings of the KSPS conference
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• 2005.04a
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• pp.49-52
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• 2005

Cepstral Mean Subtraction (CMS) makes effectively compensation for a channel distortion, but there are some shortcomings such as distortions of feature parameters, waiting for the whole speech sentence. By assuming that the silence parts have the channel characteristics, we consider the channel normalization using subtraction of cepstral means which are only obtained in the silence areas. If the considered techniques are successfully used for the channel compensation, the proposed method can be used for real time processing environments or time important areas. In the experiment result, however, the performance of our method is not good as CMS technique. From the analysis of the results, we found potentiality of the proposed method and will try to find the technique reducing the gap between CMS and ours method.

• 전자공학회논문지 IE
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• v.49 no.2
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• pp.9-17
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• 2012

One of the problems on the application of the speech recognition system in the real world is the degradation of the performance by acoustical distortions. The most important source of acoustical distortion is the additive noise. This paper describes a spectral compensation technique based on a spectral peak enhancement scheme followed by an efficient noise subtraction scheme for noise robust speech recognition. The proposed methods emphasize the formant structure and compensate the spectral tilt of the speech spectrum while maintaining broad-bandwidth spectral components. The recognition experiments was conducted using noisy speech corrupted by white Gaussian noise, car noise, babble noise or subway noise. The new technique reduced the average error rate slightly under high SNR(Signal to Noise Ratio) environment, and significantly reduced the average error rate by 1/2 under low SNR(10 dB) environment when compared with the case of without spectral compensations.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.10
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• pp.2551-2561
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• 2014

Several algorithms have been developed to detect AFIB(Atrial Fibrillation) which either rely on the linear and frequency analysis. But they are more complex than time time domain algorithm and difficult to get the consistent rule of irregular RR interval rhythm. In this study, we propose algorithm for optimal value detection of irregular RR interval for AFIB classification based on linear analysis. For this purpose, we detected R wave, RR interval, from noise-free ECG signal through the preprocessing process and subtractive operation method. Also, we set scope for segment length and detected optimal value and then classified AFIB in realtime through liniar analysis such as absolute deviation and absolute difference. The performance of proposed algorithm for AFIB classification is evaluated by using MIT-BIH arrhythmia and AFIB database. The optimal value indicate ${\alpha}=0.75$, ${\beta}=1.4$, ${\gamma}=300ms$ in AFIB classification.

• Journal of KIISE:Software and Applications
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• v.32 no.7
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• pp.625-635
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• 2005

In this paper, we propose a hybrid approach for segmenting the lungs efficiently and automatically in chest CT images. The proposed method consists of the following three steps. first, lungs and airways are extracted by two- and three-dimensional automatic seeded region growing and connected component labeling in low-resolution. Second, trachea and large airways are delineated from the lungs by two-dimensional morphological operations, and the left and right lungs are identified by connected component labeling in low-resolution. Third, smooth and accurate lung region borders are obtained by refinement based on image subtraction. In experiments, we evaluate our method in aspects of accuracy and efficiency using 10 chest CT images obtained from 5 patients. To evaluate the accuracy, we Present results comparing our automatic method to manually traced borders from radiologists. Experimental results show that proposed method which use connected component labeling in low-resolution reduce processing time by 31.4 seconds and maximum memory usage by 196.75 MB on average. Our method extracts lung surfaces efficiently and automatically without additional processing like hole-filling.

• Journal of the Korea Society of Computer and Information
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• v.14 no.11
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• pp.179-186
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• 2009

In this paper, we propose a head detection method based on vertical and horizontal pixel histogram analysis in order to overcome drawbacks of the previous head detection approach using Haar-like feature-based face detection. In the proposed method, we create the vertical and horizontal foreground pixel histogram images from the background subtraction image, which represent the number of foreground pixels in the same vertical or horizontal position. Then we extract feature points of a head region by applying Harris corner detection method to the foreground pixel histogram images and by analyzing corner points. The proposal method shows robust head detection results even in the face image covering forelock by hairs or the back view image in which the previous approaches cannot detect the head regions.

• Journal of Labour Economics
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• v.33 no.3
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• pp.47-88
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• 2010

Focusing on the Korean experience, particularly a recent amendment which extends maternity leave and increases financial benefits during maternity and childcare leave, this paper evaluates how such an expansion of benefits affects the employment and the hourly wages of young wages of childbearing age. Empirical results from a difference--in-difference-in-differences model having older warren, older men, and young men simultaneously as the control group suggest that neither the employment nor the hourly wages of young women are affected. This implies that the law change does not cause shifts in the labor supply curve and the labor demand curve for young women.

• The Journal of the Acoustical Society of Korea
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• v.23 no.3
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• pp.228-234
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• 2004

In this paper, we proposed the compensation technique that overcomes the limitations of the conventional approaches through summing up the bias terms between world's codebook and individual codebook vectors of feature parameters. But, mean compensation without condition can bring higher false acceptance. Therefore, the proposed technique compensates the channel mis-match condition by weighted bias sum using nonlinear function regarding to the distortion between speech and silence. The simulation results show that the FRR (flase reject rate) is decreased 14.95% when the proposed algorithm was applied.

• The Bulletin of The Korean Astronomical Society
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• v.43 no.1
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• pp.40.2-40.2
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• 2018

외계행성 탐색시스템으로 관측한 영상은 한국천문연구원 본원에 있는 자료처리 시스템으로 실시간 전송된다. 이를 위해 한국과학기술정보연구원이 운영 중인 첨단망과 UDP 전송 프로그램을 활용하고 있으며 연간 약 140TB의 관측 영상을 칠레 55Mbps, 남아공 39Mbps, 호주 410Mbps의 속도로 전송하고 있다. 관측 영상이 전송되면 MEF 포맷으로 구조화 하고 bias, flat, crosstalk 보정과 bad pixel masking 등의 전처리 과정을 거쳐 각 연구과제별로 실시간 배포하고 있다. 중력렌즈 연구를 위한 우리 은하 중심부 관측영상은 차감영상 기법을 사용하여 약 3억 개의 별에 대해 측광하고 있으며, $18K{\times}18K$ 크기의 대용량 관측 영상을 빠르고 효율적으로 처리하기 위해 256개로 분할하여 분산처리하고 있다. 2014년부터 자료처리를 위한 시스템을 구축하고 증설하였으며 현재 11대의 서버(212Core)와 2.7PB의 NAS 스토리지를 운영하며 연간 700TB이상의 자료를 처리하고 있다. 우리은하 중심부 측광자료에서 검출된 변광 현상을 정리하여 측광데이터베이스를 구축하였다. 본 발표에서는 KMTNet 실시간 자료처리 과정에 대한 상세한 내용과 향후 자료처리 시스템 개선방향에 대해 소개한다.