묘성증후군 환아 1예에서 관찰된 안과적 소견

김상균,김형석,김승현,Sang Kyoon Kim,Hyoung-Seok Kim,Seung Hyun Kim 대한안과학회 2008 대한안과학회지 Vol.49 No.11

적응형 문턱값을 가지는 2차 조건 사후 최대 확률을 이용한 통계적 모델 기반의 음성 검출기

김상균,장준혁,Kim, Sang-Kyun,Chang, Joon-Hyuk 한국음향학회 2010 韓國音響學會誌 Vol.29 No.1

본 논문에서는 음성의 통계적 모델에 기반한 음성 검출기 (voice activity detection, VAD)의 성능 향상을 위해 2차 조건 사후 최대 확률 (second-order conditional maximum a posteriori, second-order CMAP)기법을 적용한 우도비 테스트 (likelihood ratio test, LRT)를 제안한다. 제안된 알고리즘은, 기존의 통계적 모델에 기반한 음성 검출기와 CMAP 기반의 음성 검출기를 분석한 다음, 직전 2 프레임에서 음성의 존재와 부재에 대한 조건부 확률에 따라 실시간으로 적응형 문턱값을 구하여 기하 평균한 우도비와 비교하는 음성검출 결정법 (decision rule)을 제시한다. 제안된 알고리즘을 비정상 (non-stationary) 잡음환경에서 기존의 통계적 모델에 기반한 음성 검출기, CMAP 기반의 음성 검출기와 비교하였으며, 향상된 성능을 보였다. In this paper, we propose a novel approach to improve the performance of a statistical model-based voice activity detection (VAD) which is based on the second-order conditional maximum a posteriori (CMAP). In our approach, the VAD decision rule is expressed as the geometric mean of likelihood ratios (LRs) based on adapted threshold according to the speech presence probability conditioned on both the current observation and the speech activity decisions in the pervious two frames. Experimental results show that the proposed approach yields better results compared to the statistical model-based and the CMAP-based VAD using the LR test.

방향계 폴리에테르이미드막의 물 - 알콜 혼합액의 투과증발 특성에 관한 연구 : Ⅱ . skin layer 의 density 변화에 의한 물 - 이소프로판을 혼합액의 투과증발

김상균,제갈종건,이규호 ( S . G . Kim,J . G . Jegal,K . H . Lee ) 한국공업화학회 1997 공업화학 Vol.8 No.5

표면층에 치밀층 구배 구조를 갖는 비대칭 폴리에테르이미드막에 대하여 치밀 구조층의 화학적 개질을 통한 막 형태의 변화와 물/이소프로판을 혼합액의 투과증발 거동을 연구하였다. 치밀 정도는 증발 시간에 의해 조절되었고, 증발 시간이 0분에서 4분으로 증가되었을때, 투과량은 감소하였고, 선택도는 증가하였다. 또한, 수산화나트륨 용액으로 개질 된 폴리에테르이미드막을 통한 투과증발 거동은, 치밀 표면층의 개질 시간이 증가될수록 선택성은 증가하였고, 투과량은 감소하였다. 전자현미경으로 확인된 형태 변화는 개질 시간의 증가에 따라 치밀 표면층의 density 증가를 보여주었고, 이러한 결과는 위의 관찰들과 일치하였다. For asymmetric polyetherimide membranes having a dense layer gradient structure on the skin layer, the morphology change and pervaporation behaviors of water/isopropanol mixture through chemical modification of dense skin layer were investigated. The extent of the density was controlled by the evaporation time, and when the evaporation time was increased from 0 min to 4 min, the permeation flux was decreased, the separation factor was increased. Also, the pervaporation behaviors of the polyetherimide membranes modified with sodium hydroxide solution, as the modification time of dense skin layer increased, the selectivity increased, and the permeation flux decreased. The morphology change identified by SEM shows that the density of dense skin layer tends to increases with increasing modification time, this result is consistent with above observations.

조건 사후 최대 확률과 음성 스펙트럼 변이 조건을 이용한 통계적 모델 기반의 음성 검출기

김상균,장준혁,Kim, Sang-Kyun,Chang, Joon-Hyuk 한국음향학회 2011 韓國音響學會誌 Vol.30 No.6

본 논문에서는 조건 사후 최대 확률 (conditional maximum a posteriori, CMAP)과 음성 스펙트럼 변이 조건을 기반으로 한 새로운 음성 검출기 (voice activity detection, VAD)를 제안한다. 제안된 음성 검출기는 통계적 모델을 기반으로 한 우도비 테스트 (likelihood ratio test, LRT)의 문턱값을 결정하는데 조건 사후 최대 확률과 스펙트럼 변이의 상태 값을 조건부 확률로 부과한다. 제안된 알고리즘을 다양한 잡음 환경에서 기존의 CMAP 기반의 음성 검출기와 비교한 결과 전체적으로 향상된 성능을 보였으며 특히 SNR이 낮은 조건에서 향상 폭이 컸다. In this paper, we propose a novel approach to improve the performance of a statistical model-based voice activity detection (VAD) which is based on the conditional maximum a posteriori (CMAP) with deviation. In our approach, the VAD decision rule is expressed as the geometric mean of likelihood ratios (LRs) based on adapted threshold according to the speech presence probability conditioned on both the speech activity decisions and spectral deviation in the pervious frame. Experimental results show that the proposed approach yields better results compared to the CMAP-based VAD using the LR test.

지속가능한 발전을 위한 발걸음

김상균,Kim, Sang-Gyun 환경보전협회 2007 환경정보 Vol.29 No.371

SET에 대한 이해

김상균,Kim, Sang-Gyun 한국데이터베이스진흥원 1997 디지털콘텐츠 Vol.12 No.-

전자상거래의 사실상의 보안표준 프로토콜로 부상하고 있는 SET에 대해 그 구체적인 모습과 역할, 구성요소에 대해 알아보도록 하겠다.

Beveridge 보고서의 작성(作成) 및 입법과정(立法過程)에 관한 연구(硏究)

김상균,Kim, Sang-Gyun 한국사회복지학회 1986 한국사회복지학 Vol.7 No.-

돈(豚)의 간회충증(肝蛔蟲症)에 관(關)한 병리학적(病理學的) 검색(檢索)

김상균,임창형,Kim, Sang Kyun,Lim, Chang Hyeong 대한수의학회 1970 大韓獸醫學會誌 Vol.10 No.1

1. Hepatic ascariasis represented by milk spots on the liver surface was found in 475(31.7%) out of 1,500 pigs. 2. For histopathological studies, 170 cases were collected at random from the milk spotted liver From these cases ascaris larva was found in 14 cases(8.2%). 3. Grossly, the occurrence of milk spots was not confined to any particular lobes of the liver. The lesions, however, were more frequently found in the diaphragmatic surface than in the visceral surface. The extent of the spots was limited to the subcapsular region and the deeper tissue was not affected. 4. Histologically, hemorrhage and eosinophilic infiltration were observed in the area invaded by the larva. The increase of connective tissue followed by a form of chronic lymphocytic hepatitis was observed at the late stage of infection. There was numerous eosinophilic infiltration around the larva trapped in the liver tissue. Consequently, encapsulation of the larva was followed by organization and calcification.

재발된 간헐외사시에서 순응도에 따른 부분가림치료의 장기적 효과

김상균,이승태,김승현,조윤애,Sang Kyoon Kim,MD,Sung-Tae Yi,MD,Seung-Hyun Kim,MD,PhD,Yoonae A,Cho,MD,PhD 대한안과학회 2009 대한안과학회지 Vol.50 No.1

Purpose: To evaluate the reoperation rate and the change of exo-angle according to compliance level of part time occlusion therapy in recurrent intermittent exotropia. Methods: This retrospective study included 52 patients of recurrent intermittent exotropia who followed up more than 5 years after their first operation. They were ordered part time occlusion therapy for recurrent exotropia. The patients were divided into 4 groups according to the level of compliance of part time occlusion therapy (\'excellent\', \'good\', \'fair\', \'poor\'). We evaluated the reoperation rate in 5 years after the first operation and the change of exo-angle from the early recurrent time according to compliance levels. Results: The reoperation rate within 5 years after the first operation of \'excellent\' and \'good\' compliance groups was lower than that of \'fair\' and \'poor\' groups (33.3, 26.3, 73.7 and 45.5% respectively) and the degree of exo-angle progression from the early recurrent time of the \'excellent\' and \'good\' compliance groups was less than that of \'fair\' and \'poor\' compliance groups, both results of which were statistically significant (p=0.02, 0.03). Conclusions: Part time occlusion therapy in recurrent intermittent exotropia has good long-term effects of decreasingreoperation rates in patients with a high level of compliance.

에피라식 후 각막상피편 보존 여부에 따른 초기 통증 및 상피 창상 치유 기간의 비교

김상균,송종석,김효명,Sang Kyoon Kim,Jong Suk Song,Hyo Myung Kim 대한안과학회 2008 대한안과학회지 Vol.49 No.12

Purpose: To investigate the influence of preservation of an epithelial sheet in Epi-LASIK on postoperative pain and epithelial wound healing time. Methods: This prospective study included 34 eyes of 17 patients with myopia who received Epi-LASIK. An epithelial flap was created using the epikeratome (Centurion SES, Norwood Abbey EyeCare, Australia). After the stroma was ablated using the MEL 80 (Carl Zeiss Meditec. Germany) excimer laser, the epithelial sheet was replaced on the stromal bed in one randomly selected eye of each patient, and removed in the contralateral eye. The pain scores at postoperative day 0, 1, 2, 5 and the numbers of days for the complete epithelial wound healing were compared between the sheet-preserved and the sheet-removed eyes. At 1 month postoperative, uncorrected visual acuity (UCVA), refractive error and corneal haze were also compared. Results: Pain scores on the day of operation were lower in sheet-preserved group and statistically significant (p=0.01). On postoperative day 1, 2, and 5, pain scores did not reach statistical significance (p=0.24, 0.08, 0.56, respectively). The mean epithelial healing time was 4.88±0.93 days for the flap-preserved eyes and 4.29±0.77 days for the flap-removed eyes, which showed statistical significance (p=0.01). No significant difference was noted between the 2 groups for mean UCVA, corneal haze and refractive error at 1 month postoperative. Conclusions: A preserved epithelial sheet reduced early postoperative pain but did not accelerate epithelial wound-healing rate.