LPCA에 기반한 GMM을 이용한 화자 식별

서창우,이윤정,이기용,Seo, Chang-Woo,Lee, Youn-Jeong,Lee, Ki-Yong 한국음성학회 2005 음성과학 Vol.12 No.2

An efficient GMM (Gaussian mixture modeling) method based on LPCA (local principal component analysis) with VQ (vector quantization) for speaker identification is proposed. To reduce the dimension and correlation of the feature vector, this paper proposes a speaker identification method based on principal component analysis. The proposed method firstly partitions the data space into several disjoint regions by VQ, and then performs PCA in each region. Finally, the GMM for the speaker is obtained from the transformed feature vectors in each region. Compared to the conventional GMM method with diagonal covariance matrix, the proposed method requires less storage and complexity while maintaining the same performance requires less storage and shows faster results.

상백피(桑白皮)가 주약(主藥)으로 배오(配伍)된 방제(方劑)의 활용(活用)에 대한 고찰(考察) (동의보감 상백피 가미방 중심으로)

서창우,이장천,Seo Chang-Woo,Lee Jang-Cheon 대한한의학방제학회 2004 大韓韓醫學方劑學會誌 Vol.12 No.2

This study was investigated to make sure the range of the Morus Cortex's treatment, the nature of disease, the chief virtue of medicine, the pathology and the usage quantity of it in Donguibogam The results were as follows; 1. The frequency of being used the Morus Cortex in the consumption or cough-relative chapter is as high as a ratio of 40.6%. 2. The Morus Cortex is used in a realm of the consumption or cough-relative disease, an otorhinolalyngology, an edema, a skin-relative disease, a bleeding trouble, a thirsty and diabetes melitus, etc. 3. The Morus Cortex is used in a realm of the pathology of the pulmonary heat, the pulmonary noxious vigor, the damage from external winds and colds, fatigue, etc. 4. The Morus Cortex is used in a range of $1g{\sim}12g$ in herbal-prescription. The main using dosage is 4g(about 42%). 5. The Morus Cortex is used with various crude herbs in accordance with the pathogeny. The Morus Cortex has been used to reduce heat from the lungs and soothe asthma, to promote urination and reduce edema from shinnongboncho era. According to the results, I suggest that we use the Morus Cortex in a various pathogenic fields. The Morus Cortex is able to remove not only pathogenic heat from the consumption or cough-relative disease, but also pathogenic otorhinolalyngology, an edema, a skin-relative disease, a bleeding trouble, a thirsty and diabetes melitus, etc.

AMC와 MIMO 기법이 결합된 Adaptive-MCM 시스템의 성능 분석

서창우,조인식,윤길상,이정환,황인태,Seo, Chang-Woo,Joe, In-Sik,Yoon, Gil-Sang,Lee, Jung-Hwan,Hwang, In-Tae 한국정보통신학회 2010 한국정보통신학회논문지 Vol.14 No.2

본 논문에서는 AMC(Adaptive Modulation and Coding) 기법에 MIMO(Multiple Input Multiple Output) 기법이 결합된 Adaptive-MCM(Modulation, Coding and MIMO) 시스템을 제안하고, 모의실험을 통해 그 성능을 분석한다. AMC 기법은 채널 환경에 따라서 변조방식, 코드율을 적응적으로 변화시켜 전송률과 신뢰도의 향상을 가져온다. 제안된 Adaptive-MCM 시스템은 채널 환경에 따라서 MIMO 기법을 적응적으로 활용함으로써 기존의 변조방식과 코드율의 조합에 국한된 AMC 기법보다 더욱 향상된 전송률과 에러 성능을 가져 오게 한다. 제안된 시스템의 성능 분석은 Adaptive-MCM 시스템을 적용한 시스템과 적용하지 않은 시스템의 각 전송률 결과를 바탕으로 비교 수행되었다. 실험결과, Adaptive-MCM 시스템을 적용함으로써 각 MCMS(Modulation, Coding, and MIMO Scheme) 레벨에 해당하는 조합을 고정적으로 사용하는 시스템에서 나타났던 SNR(Signal to Noise Ratio) 확보와 데이터율 증가 사이의 Trade-Off 관계 개선이 이루어졌으며, 이를 통해 평균 데이터율의 향상을 가져올 수 있었다. The proposal set out in this paper, is the Adaptive-MCM(Modulation, Coding and MIMO) system, which results from the combination of adaptive modulation and coding (AMC) and multiple input multiple output (MIMO) schemes. The performance of this system is analyzed through computer simulation. By using the MIMO scheme adaptively as well, the proposed Adaptive-MCM system, presents a better improvement of data rate and error performance compared to the AMC system. The throughput performance of the Adaptive-MCM system is analyzed and compared with the throughput performance of Non-Adaptive-MCM Systems. As a result of the simulation, we can infer that, at a fixed MCM level, there is an improvement of the trade-off between secure Signal to Noise Ratio (SNR) and a high data rate. Consequently, this trade-off improvement results in a better average data rate.

동의보감(東醫寶鑑) 중(中) 천화분(天花粉)이 주약(主藥)으로 배오(配伍)된 방제(方劑)의 활용(活用)에 대한 고찰(考察)

서창우,유진덕,Seo Chang-Woo,Liu Chen-Duk 대한한의학방제학회 2003 大韓韓醫學方劑學會誌 Vol.11 No.1

Through the research into the date of Radix Thichosanthis main blended 21 kinds of prescriptions Radix Thichosanthis from Donguibogam. This study summrized as follows; The suitable dosage of Radix Thichosanthis per one application is one to two don(about $4{\sim}8g$). Radix Thichosanthis Radix main blended prescriptions broadly use in the symptoms of diabetes, excessive thirst, cabuncles and eye diseases In diabetes and excessive thirst, the structes of Radix Thichosanthis main blended prescriptions are commonly used Seng Mak San(生脈散), Radix Puerariae(葛根), Frectus Schisandrae(五味子), Radix Ophiopogonis(麥門冬) In Furuncles, Carbuncles and Cancer like diseases, the structes of Radix Thichosanthis main blended prescriptions are generally used Kumeunhwasan(金銀花散), Jipaesan(芷貝散), Twonongsan(透膿散).

PDA 환경에서 자동화자 확인의 계산량 개선을 위한 연구

서창우,임영환,전성채,장남영,Seo, Chang-Woo,Lim, Young-Hwan,Jeon, Sung-Chae,Jang, Nam-Young 한국융합신호처리학회 2009 융합신호처리학회 논문지 (JISPS) Vol.10 No.3

본 논문은 PDA 디바이스에서 개인정보를 보호하기 위한 자동화자확인 시스템을 제안한다. 최근 M-커머스와 같은 모바일 환경을 위한 PDA의 용량이 확장되고 사용이 증가되고 있다. 그러나 너무 많은 계산량 때문에 PDA 디바이스에서 자동화자확인의 실질적인 응용은 여전히 많은 어려움이 존재한다. 본 논문에서는 이러한 문제점을 해결하기 위해서 음성발성 동안 스펙트럼 차감법과 음성 검출과 같은 전처리를 수행함으로써 계산량을 줄일 수 있는 방법을 적용하였다. 또한 빠른 처리 결과를 얻기 위한 은닉마코프모델의 최적 상태 정합과 시퀀스 확률비 테스트를 적용하였다. 전체적인 시스템은 PDA디바이스의 제한된 메모리와 낮은 CPU 속도에 적합하도록 간결하게 구현하였다. In this paper, we propose real time automatic speaker verification (ASV) system to protect personal information on personal digital assistant (PDA) device. Recently, the capacity of PDA has extended and been popular, especially for mobile environment such as mobile commerce (M-commerce). However, there still exist lots of difficulties for practical application of ASV utility to PDA device because it requires too much computational complexity. To solve this problem, we apply the method to relieve the computational burden by performing the preprocessing such as spectral subtraction and speech detection during the speech utterance. Also by applying the hidden Markov model (HMM) optimal state alignment and the sequential probability ratio test (SPRT), we can get much faster processing results. The whole system implementation is simple and compact enough to fit well with PDA device's limited memory and low CPU speed.

천식동물모델을 이용한 지골피(地骨皮), 상백피(桑白皮) 및 두 배합약물의 실험적 연구

서창우,이영철,이장천,Seo, Chang-Woo,Lee, Young Cheol,Lee, Jang-Cheon 대한한의학방제학회 2013 大韓韓醫學方劑學會誌 Vol.21 No.1

Objectives : To clarify the possible effect of Lycium chinese Mill (LC)., Morus alba L (MA)., and Lycium chinese Mill. +Morus alba L. (LC+MA), we have examined their influence on the development of pulmonary eosinophilic inflammation in the asthmatic murine model. Methods : Female Balb/c mice (5weeks) were immunized on two different days (21 days and 7 days before inhalational exposure) by intraperitonial injections of 0.2ml alum-precipitated Ag containing $100{\mu}g$ of OVA bound to 4 mg of aluminum hydroxide in PBS. Seven days after the second sensitization, mice were exposed to aerosolized ovalbumin for 30 minutes/day on 3 days/week for 8 weeks (at a flow rate of 250 L/min, 2.5% ovalbumin in normal saline) and, LC, MA, and LC+MA (500 mg/kg) were orally administered 3 times per a week for 8 weeks. Results : The suppressive effect of LC, MA, and LC+MA were demonstrated by the accumulation of eosinophills into airways, with the reduction of eosinophil, total lung leukocytes numbers. These were correlated with the marked reduction of IL-5, IL-13 and IL-4 levels in the BALF and serum. OVA-specific IgE levels were also decreased in serum and BAL from these mice. LC, MA, and LC+MA decreased eosinophil CCR3 expression and CD11b expression in lung cells. Conclusions : These results indicate that LC, MA, and LC+MA have high inhibitory effects on airway inflammation and hyper-responsiveness in the asthmatic murine model. The suppression of IL-5, IgE, eosinophil CCR3 expression and CD11b expression, and the increase of IFN-${\gamma}$ production in BALF seem to contribute to this effect. Hence, the results indicated that LC, MA, and LC+MA could act as a immuno-modulator which possesses anti-inflammatory and anti-asthmatic property by modulating the imbalance between Th1 and Th2 cytokines.

제강 2차 정련 슬래그를 재활용한 칼슘설포알루미네이트(CSA) 합성 및 수화 특성

서창우 ( Chang Woo Seo ),김선효 ( Seon Hyo Kim ),고상진 ( Sang Jin Ko ),김상현 ( Sang Hyun Kim ),조규용 ( Kyu Young Jo ) 대한금속·재료학회 2008 대한금속·재료학회지 Vol.46 No.7

디지털 회로용 고장 시뮬레이션 기술의 개선기법

서창우(Chang-Woo Seo),장종권(Jong-Kwon Chang) 대한전자공학회 1994 대한전자공학회 학술대회 Vol.1994 No.7

화자인식에서 균등한 인식률을 얻기 위한 빠른 순시 확률비 테스트 적용

서창우(Chang-Woo Seo),이동훈(Dong-Hoon Lee),마미연(Mi-Youn Ma),전성채(Sung-Chae Jeon),허영(Young Huh) 대한전자공학회 2010 대한전자공학회 학술대회 Vol.2010 No.6

In this paper, a fast sequential probability ratio test (FSPRT) method that shows consistent performances at all times regardless of the compositions of vocalized sentences for speaker recognition(SR) will be proposed. In generating frames, the FSPRT will first conduct SR test processes with only generated frames without any overlapping and if the results do not satisfy discrimination criteria, the FSPRT will sequentially use frames applied with overlapping. Experimental results show that the FSPRT has better performance to the conventional method while requiring less complexity with equal error rates (EER).

프리앰블을 이용한 새로운 SNR 추정 알고리즘 제안 및 성능 분석

서창우(Chang-woo Seo),윤길상(Gil-sang Yoon),셰를리 포루투갈(Sherlie Portugal),황인태(In-tae Hwang) 大韓電子工學會 2011 電子工學會論文誌-TC (Telecommunications) Vol.48 No.3

이동통신이 발전해 감으로써 사용자들은 점점 더 높은 데이터율과 신뢰성이 높은 통신 시스템을 요구하고 있다. 최근에는 이러한 사용자 요구에 부합하기 위해 MIMO(Multiple Input Multiple Out)와 OFDM(Orthogonal Frequency Division multiplexing)의 장점을 모두 활용하는 MIMO-OFDM에 기반을 둔 시스템 개발이 활발히 이루어지고 있다. 또한, 빠른 무선채널 환경에 대응하여 높은 전송률 및 양질의 데이터를 만족하기 위해서 채널 상태에 따라서 적응적으로 변조, 코딩, 부 반송파수 및 파워 할당을 달리하는 시스템 등이 결합되고 있다 . 이러한 피드백 기반 시스템은 얼마나 정확히 채널에 대한 상태정보(CSI : Channel State Information)를 지연 없이 송신기에 전달하느냐에 따라서 시스템 전체 성능이 향상 될 수 있고 저하될 수 있다. 본 논문에서는 송 · 수신단에서 서로 알고 있는 프리앰블(Preamble)을 이용하여 채널 추정과정 없이 정확한 SNR(신호 대 잡음비: Signal to Noise Ratio) 추정이 가능한 알고리즘을 제안한다. 여러 채널 환경에서 수행한 모의 실험결과, 제안 알고리즘은 기존의 프리앰블 기반 SNR 추정 알고리즘들 보다 가장 정확하게 SNR을 추정하는 것을 확인할 수 있었다. The fast growing of the number of users requires the development of reliable communication systems able to provide higher data rates. In order to meet those requirements, techniques such as Multiple Input Multiple Out (MIMO) and Orthogonal Frequency Division multiplexing (OFDM) have been developed in the recent years. In order to combine the benefits of both techniques, the research activity is currently focused on MIMO-OFDM systems. In addition, for a fast wireless channel environment, the data rate and reliability can be optimized by setting the modulation and coding adaptively according to the channel conditions; and using sub-carrier frequency, and power allocation techniques. Depending on how accurate the feedback-based system obtain the channel state information (CSI) and feed it back to the transmitter without delay, the overall system performance would be poor or optimal. In this paper, we propose a Signal to Noise Ratio (SNR) estimation algorithm where the preamble is known for both sides of the transciever. Through simulations made over several channel environments, we prove that our proposed SNR estimation algorithm is more accurate compared with the traditional SNR estimation.