디지털 디스플레이포트 IC 설계

이행우 남서울대학교출판국 2008 남서울대학교 정보통신 논문집 Vol.5 No.2

This technology solves the wide bandwidth and the high resolution requiring for the future wide-screen display system, is the new display standard which can integrate various display interface such as analog VGA, digital OVI etc. The goal of this research is a design of Displayport IC for that standard. The developed IC would use at the transmit part and receive part of the display interfaces. And then it is expected that this IC will replace the current digital display interfaces after a few years. 본 기술은 미래 대화면 디스플레이의 인터페이스에 필요한 광대역과 고해상도 문제를 해결하고, 현재와 같이 아날로그 VGA 및 디지털 DVI 등 여러 디스플레이 인터페이스를 하나로 통합할 수 있는 새로운 표준이다. 이를 실현하는 디스플레이 포트 IC 설계가 연구목표이다. 개발한 IC는 디스플레이 인터페이스의 송신장치 및 수신장치에 각각 사용되어 앞으로 수년 내에 디지털 디스플레이 인터페이스를 대체할 것으로 전망되고 있다.

白癬症과 Candida 症에 關한 臨床 및 眞菌學的 硏究

李行雨,卞東吉 고려대학교 의과대학 1974 고려대 의대 잡지 Vol.11 No.1

Studies on the correlation between clinical findings and mycological results of dermatophytosis and candidiasis, and recent distribution of causative organisms of dermatophytosis, were made by investigating 561 clinical mycotic lesions among out-patients of Korea University Medical College Hospital, during a period from March, 1971 to August, 1973. Author also investigated pathogenic fungi distributed on 86 normal 4th toe webs of healthy adults and the varieties of contaminants and it's distribution which were supposed to be reducing the positive culture results. The results obtained were as follows : 1) From keratinous specimens of 86 normal 4th toe webs of healthy adults, fungal elements were detected in 8 cases (9.3%) microscopically by KOH preparation. Eight dermatophytes (9.3%) and 23 candida (26.7%) were isolated by culture examinations. Total 31 cases (36.0%) revealed positive results in either one of both examinations. 2) Among 561 clinical fungal lesions, fungal elements were detected in 448 lesions (74.3%) by KOH preparation. By culture examination, dermatophytes in 350 lesions (62.3%) and candida 128 lesions (22.8%) were isolated. Twenty-nine lesions, however, revealed negative results in either examination 3) Among 353 clinical dermatophytic lesions, candida were isolated in 15 lesions (4.2%) without the isolation of dermatophytes and from 125 clinical candidial lesions the dermatophytes were isolated in 12 lesions (9.6%) without the isolation of candida. 4) The predominant causative organism of all dermatophytic diseases of the glabrous skin was found consistently to be the trichophyton rubrum. The remainders were trichophyton mentagrophytes, epidermophyton floccosum, and trichophyton ferrugineum in decreasing order of frequency. These distribution patterns of causative organism were similar in both hyperkeratotic and vesicular lesions of feet infections. In interdigital lesions, however, the candida (28.1%) was found higher in incidence than trichophyton mentagrophytes (14.4%). 5) The thumb and great toe nails were invaded more frequently than the others and declined in incidence as approaching toward 5th finger and toe nails. The dermatophytic nail infections were more prevalent in the toe nails than in finger nails. In candidial infections, however, the reverse was true. 6) Trichophyton rubrum was the most frequent causative organism in all lesions of the distal invasions of the nails. Trichophyton mentagrophytes, however, was predominant in leukonychia and candida prevalent in paronychial change. 7) Predominant contaminants which disturbed culture examination were aspergillus, penicillium, and hormodendrum, in decreasing order of frequency.

PN 부호의 알고리즘 개선을 이용한 다원접속간섭의 제거방법

이행우 남서울대학교출판국 2010 남서울대학교 정보통신 논문집 Vol.7 No.2

In DS-CDMA method, mutiple mobile stations own jointly one radio channel and are made to use a PN code (Pseudo-Noise Code) for the purpose of ffillllmlze interference. However, corelation value of PN code is one when time delay is zero but the corelation value is 1/ N when time delay is not O. Therefore corelation characteristic does not fully attained. As a result, when the user increase, the performance degradation and system capacity problem will be able to occur by interference among users. In this paper, the PN code has ideally self corelation. Uses the PN code which has offset with removes Mu1tiple Access Interferemce of the users between proved.

방조제 이질층의 투수성이 제체 침투에 미치는 영향에 대한 모의 분석

이행우,장병욱,손영환,김성필,Lee, Haeng-Woo,Chang, Pyoung-Wuck,Son, Young-Hwan,Kim, Seong-Pil 한국농공학회 2006 한국농공학회논문집 Vol.48 No.6

A simulation was done to analyze the seepage problems due to seawater intrusion through the embedded rock layers on heterogeneous layers of sea-dike. Numerical analysis with SAMTLE(developed by author) was done by taking various relative permeability $ratio(R_r/R_e)$. These results showed, when the sed-dike is newly designed, operated, and maintained considering the safety of sea-dike in seepage problems, these embankment materials are prudently chosen. The permeability of the soil materials, within the range of salinity management in freshwater, is comparatively high, however, the permeability of rock materials for bottom rock layer is low. Therefore, when the relative permeability $ratio(R_r/R_e)$ is bellow 10 it is safety in seepage problems of sea-dike.

암묵신호분리를 이용한 스테레오 음향반향제거기

이행우 (사)디지털산업정보학회 2012 디지털산업정보학회논문지 Vol.8 No.3

This paper is on a stereo acoustic echo canceller with the blind signal separation. The convergence speed of the stereo acoustic echo canceller is deteriorated due to mixing two residual signals in the update signal of each echo canceller. To solve this problem, we are to use the blind signal separation(BSS) method separating the mixed signals. The blind signal separation method can extracts the source signals by means of the iterative computations with two input signals. We had verified performances of the proposed acoustic echo canceller for stereo through simulations. The results of simulations show that the acoustic echo canceller for stereo using this algorithm operates stably without divergence in the normal state. And, when the speech signals were inputted, this echo canceller achieved about 3dB higher ERLE in the case of using the BSS algorithm than the case of not using the BSS algorithm. But this echo canceller didn’t get good performances in the case of inputting the white noises as stereo signals.

개선된 직교투사 알고리즘을 이용한 음향궤환제거기

이행우 (사)디지털산업정보학회 2012 디지털산업정보학회논문지 Vol.8 No.2

This paper is on an improved orthogonal projection method which can cancel the acoustic feedback signals in the digital hearing aids. Comparing with the NLMS algorithm which is widely used for simplicity and stability, it shows that this method has the improvement of the convergence performances, and has small computational quantities, for signals with the large auto­correlation as speech signals. This uses the improved orthogonal projection algorithm which reduces the correlation of signals. To verify the convergence characteristics of the proposed algorithm, we simulated about various input signals. The acoustic feedback canceller has a 12­bit resolution with 64­tap adaptive FIR filter. And we compared the results of simulation for this algorithm with the ones for the NLMS algorithm. By these works, it is proved that the feedback canceller adopting the proposed algorithm shows about 3.5dB more high SNR than the NLMS algorithm in the colored input signals.

방조제 바닥사석층의 규모가 제체 침투문제에 미치는 영향에 대한 모의 분석

이행우,장병욱,송창섭,원정윤,Lee Haeng Woo,Chang Pyoung Wuck,Song Chang Seob,Won Jeong Yun 한국농공학회 2006 한국농공학회논문집 Vol.48 No.1

Numerical analyses were carried out for studying on seepage problems due to seawater intrusion through the embedded rock layers of the sea-dike. A seepage analysis model, SAMTLE was developed fur two-layer embankment system. The analyses by SAMTLE showed that the size of embedded rock layer had a significant effect on the seepage problems of sea-dike. If the embedded rock layer is longer and thicker, the seepage problems become more serious to water head, seepage rate and safety factor of piping in embankment. On the other hand, if the width of embedded rock layer is equivalent to the sea-dike's bottom width, the water head becomes lower and seepage rate and safety factor of piping are dramatically increasing. This makes another seepage problems such that the fresh water becomes saltier and higher seepage rates result in internal erosion of sea-dike.

스테레오 음향반향제거기의 BSS 후처리방법

이행우 (사)디지털산업정보학회 2014 디지털산업정보학회논문지 Vol.10 No.1

This paper is on a stereo acoustic echo canceller with the blind signal separation for postprocessing. The convergence speed of the stereo acoustic echo canceller is deteriorated due tomixing two residual signals which are update signals of each echo canceller. To solve thisproblem, we are to use the blind signal separation(BSS) method separating the mixed signalsafter the echo cancellers. The blind signal separation method can extracts the source signalsby means of the iterative computations with two input signals. We had verifiedperformances of the proposed acoustic echo canceller for stereo through simulations. Theresults of simulations show that the acoustic echo canceller for stereo using this algorithmoperates stably without divergence in the normal state. And, when the speech signals wereinputted, this echo canceller achieved about 2dB higher ERLE with the BSS post processingmethod than without this method. This stereo echo canceller showed the best performance inthe case of inputting the real voice signal.

비상관 잡음을 이용한 음향반향제거기

이행우 남서울대학교출판국 2011 남서울대학교 정보통신 논문집 Vol.8 No.1

This paper is on a new adaptive algorithm which can cancel the acoustic echo signals in the speaker-phone system. The proposed algorithm uses the normalized LMS algorithm with decorrelators. By doing so, it can be reduced the autocorrelation for the voice signals. As the results of simulations, it is proved that the echo canceller adopting this algorithm shows the improved ERLE of about more than 6 dB. Key Words : Speaker-phone, Echo cancellation, Decorrelation

디지털 보청기를 위한 음향궤환 몇 잡음 제거 알고리즘

이행우,Lee, Haeng-Woo 한국통신학회 2010 韓國通信學會論文誌 Vol.35 No.11c

본 논문에서는 디지털 보청기의 음향궤환 및 장음을 제거하기 위한 새로운 알고리즘을 제안한다. 이 알고리즘은 궤환신호를 제거하기 위한 궤환제거기와 잡음신호를 감소시키기 위한 잡음제거기를 결합한 구조로 구성된다. 여기서 궤환제거기는 일반적인 적응 FIR 필터를 사용하여 구현하고 잡음제거기는 Wiener 해법을 이용하여 주파수 영역에서 구현한다. 이 잡음제거는 각 신호들의 전력 스펙트럼 밀도를 구하여 전달함수를 표현하는 것으로 이루어진다. 본 연구에서 제안한 궤환 및 잡음제거기의 성능을 검증하기 위하여 시뮬레이션 프로그램을 작성하고 모의실험을 수행하였다. 실험 결과, 제안한 적응 알고리즘을 사용하면 경로이득 0dB에서 기존의 알고리즘을 사용하는 경우보다 평균 10.85dB의 출력 SNR, 경로이득 6dB에서 평균 11.04dB의 출력 SNR을 향상시킬 수 있는 것으로 확인하였다. This paper proposes a new algorithm to cancel the acoustic feedback and noise signals in digital hearing aids. The proposed algorithm combines the feedback canceller to remove acoustic feedback signals and the noise canceller to reduce background noises. The feedback canceller is implemented by normal adaptive FIR filter, and the noise canceller is implemented by using the Wiener solution in frequency domain. This noise canceller has the transfer function presented by the power spectral density of signals. To verify the performances of the proposed algorithm, the simulations were carried out for the system. As the results of simulations, it was proved that we can advance 10.85dB output SNR on the average for the forward path gain of 0dB, and 11.04dB output SNR on the average for the forward path gain of 6dB, in the case of using the proposed algorithm.