한강수계에서의 부유사 예측을 위한 LOADEST 모형의 회귀식의 평가

박윤식,이지민,정영훈,신민환,박지형,황하선,류지철,박장호,김기성,Park, Youn Shik,Lee, Ji Min,Jung, Younghun,Shin, Min Hwan,Park, Ji Hyung,Hwang, Hasun,Ryu, Jichul,Park, Jangho,Kim, Ki-Sung 한국농공학회 2015 한국농공학회논문집 Vol.57 No.2

Typically, water quality sampling takes place intermittently since sample collection and following analysis requires substantial cost and efforts. Therefore regression models (or rating curves) are often used to interpolate water quality data. LOADEST has nine regression models to estimate water quality data, and one regression model needs to be selected automatically or manually. The nine regression models in LOADEST and auto-selection by LOADEST were evaluated in the study. Suspended solids data were collected from forty-nine stations from the Water Information System of the Ministry of Environment. Suspended solid data from each station was divided into two groups for calibration and validation. Nash-Stucliffe efficiency (NSE) and coefficient of determination ($R_2$) were used to evaluate estimated suspended solid loads. The regression models numbered 1 and 3 in LOADEST provided higher NSE and $R_2$, compared to the other regression models. The regression modes numbered 2, 5, 6, 8, and 9 in LOADEST provided low NSE. In addition, the regression model selected by LOADEST did not necessarily provide better suspended solid estimations than the other regression models did.

청리자감탕이 Streptozotocin으로 유발(誘發)된 흰쥐의 당뇨병(糖尿病) 및 당뇨병합병증(糖尿病合倂症)에 미치는 영향

박윤식,윤경민,임은영,신현철,강석봉,Park, Yoon-Sik,Yoon, Gyeong-Min,Im, Eun-Yeong,Shin, Hyeon-Chul,Kang, Seok-Bong 대한한방내과학회 2010 大韓韓方內科學會誌 Vol.31 No.3

Objective : The object of this study was to observe the effects of aqueous extracts of Chunglijagam-tang(CLJGT), which has traditionally been used in Korean medicine for treating various diseases, on streptozotocin(STZ)-induced rat diabetes and related complications: diabetic nephropathy, hepatopathy and hyperlipemia. Methods : CLJGT extracts were orally administered once a day for 28 days at a dosage 50, 100 and 200mg/kg from 21 days after STZ treatment, and the changes on body weights, blood glucose levels, kidney and liver weights, serum BUN(blood urea nitrogen), creatinine, AST(aspartate transaminase), ALT(alanine aminotransferase), HDL(high-density lipoprotein), LDL (low-density lipoprotein), total cholesterol and triglyceride levels were observed with pancreatic malondialdehyde(MDA) and glutathione(GSH) contents. The results were compared with silymarin 100mg/kg. Results : Significant decrease of blood glucose levels, kidney and liver weights, serum BUN, creatinine, AST, ALT, LDL, total cholesterol, triglyceride levels, pancreatic malondialdehyde contents and significant increase of body weights, serum HDL levels, pancreatic glutathione contents were detected in CLJGT extracts 50, 100 and 200mg/kg administered groups as compared to the STZ control group. Conclusion : CLJGT extracts showed favorable effects on the STZ-induced diabetes and related complications mediated by their antioxidant effects as similar to silymarin. Therefore, it is expected that DBEH has potential for use in the management of diabetes and various diabetic complications.

시공간적 변화를 고려한 SATEEC 토양유실 평가시스템 개발

박윤식,김종건,장원석,임경재,Park, Yoon-Sik,Kim, Jong-Geon,Jang, Won-Seok,Im, Gyeung-Jae 한국수자원학회 2010 물과 미래(한국수자원학회지) Vol.43 No.7

SWAT과 SATEEC 모형을 이용한 토양유실량 비교

박윤식,김종건,허성구,김남원,안재훈,박준호,김기성,임경재,Park, Youn-Shik,Kim, Jong-Gun,Heo, Sung-Gu,Kim, Nam-Won,Ahn, Jae-Hun,Park, Joon-Ho,Kim, Ki-Sung,Lim, Kyung-Jae 한국농공학회 2008 한국농공학회논문집 Vol.50 No.1

Soil erosion is a natural process and has been occurring in most areas in the watershed. However, accelerated soil erosion rates have been causing numerous environmental impacts in recent years. To reduce soil erosion and sediment inflow into the water bodies, site-specific soil erosion best management practices(BMPs) need to be established and implemented. The most commonly used soil erosion model is the Universal Soil Loss Equation(USLE), which have been used in many countries over 30 years. The Sediment Assessment Tool for Effective Erosion Control(SATEEC) ArcView GIS system has been developed and enhanced to estimate the soil erosion and sediment yield trom the watershed using the USLE input data. In the last decade, the Soil and Water Assessment Tool(SWAT) model also has been widely used to estimate soil erosion and sediment yield at a watershed scale. The SATEEC system estimates the LS factor using the equation suggested by Moore and Burch, while the SWAT model estimates the LS factor based on the relationship between sub watershed average slope and slope length. Thus the SATEEC and SWAT estimated soil erosion values were compared in this study. The differences in LS factor estimation methods in the SATEEC and SWAT caused significant difference in estimated soil erosion. In this study, the difference was -51.9%(default threshold)${\sim}-54.5%$(min. threshold) between SATEEC and non-patched SWAT, and -7.8%(default threshold)${\sim}+3.8%$(min. threshold) between SATEEC and patched SWAT estimated soil erosion.

STEPL WEB 모형을 이용한 농촌지역 비점오염원저감 대책 모의

박윤식,금동혁,정영훈,조재필,임경재,김기성,Park, Youn Shik,Kum, Dong Hyuk,Jung, Young Hun,Cho, Ja Pil,Lim, Kyoung Jae,Kim, Ki Sung 한국농공학회 2014 한국농공학회논문집 Vol.56 No.5

Sediment-laden water is problematic in aquatic ecosystem and for hydraulic structures in a watershed, and agriculture area in a watershed is one of source areas of nonpoint source (NPS), since soil surface typically exposures due to agricultural activities. Especially, severe sediment might flow into stream when agricultural area is located near stream like the Imha-dam watershed. Soil erosion is affected by precipitation, therefore there is a need to consider precipitation characteristics in soil erosion and best management practices (BMPs) simulation. The Web-based Spreadsheet Tool for the Estimation of Pollutant Load (STEPL WEB) allows estimating long-term sediment loads and the impact of best management practices to reduce sediment loads. STEPL WEB and predicted precipitation data by MIROC-ESM model was used to estimate sediment loads and its reduction by filter strip and conversion of agricultural area to forest in the future 30 years. The result indicates that approximately 70 % of agricultural area requires filter strip installation or that approximately 50 % of agricultural area needs to be converted to forest, for 41 % of sediment load reduction.

강인한 음성향상을 위한 Minimum Statistics와 Soft Decision의 확률적 결합의 새로운 잡음전력 추정기법

박윤식,장준혁,Park, Yun-Sik,Chang, Joon-Hyuk 한국음향학회 2007 韓國音響學會誌 Vol.26 No.4

본 논문에서는 비정상적인 잡음 환경에서 음성향상을 위한 새로운 잡음 추정 기법을 제시한다. 제안된 방법은 잡음 전력 추정을 위해 주파수 채널별 음성부재확률 (SAP, Speech Absence Probability)을 선택적 가중 파라미터로 적용하여 음성 구간에서는 기존의 Minimum Statistics (MS)에 의한 잡음전력 추정치에 비중을 두고 비음성 구간에서는 Soft Decision (SD)에 기반한 잡음전력 추정치를 선택하도록 기존의 알고리즘을 결합한다. 제안된 알고리즘의 성능은 다양한 잡음 환경에서 음성향상기법에 적용하여 주관적인 음질평가 결과에 의해 평가하여 기존의 MS 또는 SD에 기반한 방법보다 향상된 결과를 나타내었다. This paper presents a new approach to noise estimation to improve speech enhancement in non-stationary noisy environments. The proposed method combines the two separate noise power estimates provided by the minimum statistics (MS) for speech presence and soft decision (SD) for speech absence in accordance with SAP (Speech Absence Probability) on a separate frequency bin. The performance of the proposed algorithm is evaluated by the subjective test under various noise environments and yields better results compared with the conventional MS or SD-based schemes.

결합된 음향학적 반향 및 배경 잡음 전력에 기반한 새로운 통합 제거 알고리즘

박윤식,장준혁,Park, Yun-Sik,Chang, Joon-Hyuk 한국음향학회 2010 韓國音響學會誌 Vol.29 No.6

본 논문에서는 주파수 영역에서 결합된 음향학적 반향 및 배경 잡음 전력에 기반한 효과적인 새로운 통합 제거 알고리즘을 제안한다. 제안된 방법에서는 반향 제거기와 배경잡음 제거기가 직렬로 연결되어 각각의 제거필터에 의해 처리되는 기존의 방법 대신에 원단 (far-end) 신호에 기반한 기중치 파라미터를 이용하여 반향 및 배경잡음 전력을 선별적으로 결합하고 결합된 신호를 하나에 제거 필터에 적용하여 두 신호를 모두 제거한다. 따라서 제안된 기법에서는 기존의 반향 및 잡음 제거기의 연결 순서에 의해 발생되는 단점을 보완하고 잔여반향신호를 효과적으로 제거할수 있도록 한다. 제안된 알고리즘은 기존의 방법과 객관적인 실험을 통해 비교 평가한 결과 다양한 테스트 환경에서 기존의 방법에 비해 전반적으로 우수한 성능을 보였다. In this paper, we propose an efficient integrated suppression algorithm based on combined power of acoustic echo and background noise. The proposed method combines the acoustic echo and noise power by the weighting parameter derived from the decision rule based on the estimated echo to noise power ratio. Therefore, in the proposed approach, the acoustic echo and noise signal are able to be reduced through only one suppression filter based on the estimated combined power. The proposed unified structure improves the problems of the residual echo and noise resulted from the conventional unified structure where the noise suppression (NS) operation is placed after the acoustic echo suppression (AES) algorithm or vice versa. The performance of the proposed algorithm is evaluated by the objective test under various environments and yields better results compared with the conventional scheme.

음향학적 반향 제거를 위한 Soft Decision 기반의 동시통화 검출

박윤식,장준혁,Park, Yun-Sik,Chang, Joon-Hyuk 한국음향학회 2009 韓國音響學會誌 Vol.28 No.3

본 논문에서는 음향학적 반향 제거(AES, acoustic echo suppression)를 위해 주파수영역에서 soft decision 기법에 근거한 새로운 동시통화 검출 (DTD, double-talk detection) 알고리즘을 제안한다. 제시된 방법은 효과적인 DTD를 위해 상관계수 (cross-correlation coefficient)에 기반하여 hard decision을 사용하는 기존의 알고리즘 대신 주파수 영역에서 입력 및 원단신호의 VAD (voice activity detection) 결과와 음성 통계모델에 기반한 soft decision 방법을 도입하여 전역 근단화자존 재확률 (GNSPP, global near-end speech presence probability)을 DTD에 적용한다. 제안된 알고리즘은 기존의 방법과 객관적인 실험을 통해 비교 평가한 결과 다양한 배경잡음 환경에서 우수한 성능을 보였다. In this paper, we propose a novel double-talk detection (DTD) technique based on soft decision in the frequency domain. In the proposed method, global near-end speech presence probability (GNSPP) considering the statistical model assumption and voice activity detection (VAD) decision of the near-end and far-end signal are applied to the DTD algorithm in the frequency domain instead of the traditional hard decision scheme using cross-correlation coefficients. The performance of the proposed algorithm is evaluated by the objective test under various environments, and yields better results compared with the conventional scheme.

소아기관지(小兒氣管支) 천식(喘息)에 관(關)한 동서의학적(東西醫學的)인 고찰(考察)

박윤식,정규만,Park Yun-Sik,Jeong Gyu-Man 대한한방소아과학회 1987 대한한방소아과학회지 Vol.2 No.1

새로운 잡음전력 추정 기법을 적용한 음향학적 반향 및 배경잡음 제거 통합시스템

박윤식,장준혁,Park, Yun-Sik,Chang, Joon-Hyuk 한국음향학회 2009 韓國音響學會誌 Vol.28 No.7

본 논문에서는 주파수 영역에서 음향학적 반향 및 잡음 제거의 통합 시스템을 위한 효과적인 잡음전력 추정 기법을 제안한다. 제안된 방법은 잡음 제거 (NS, noise suppression)가 음향학적 반향 억제 (AES, acoustic echo suppression)의 후처리단으로 결합하여 사용되는 구조에서 발생하는 잡음전력 추정오차를 줄이기 위해 마이크로폰 입력신호의 음성부재확률 (SAP, speech absence probability)을 잡음전력 갱신을 위한 스무딩 (smoothing) 파라미터로 적용한다. 따라서 제안된 기법에서는 반향 억제 후 신호에서 잡음전력 갱신을 위한 SAP를 추출하는 대신 입력신호에 대한 SAP를 NS 알고리즘에 적용함으로서 잡음 제거기가 반향 억제 후 왜곡된 잡음 스펙트럼 구간에서는 잡음전력을 갱신하지 않도록 한다. 제안된 알고리즘은 기존의 방법과 객관적인 실험을 통해 비교 평가한 결과 다양한 배경잡음 환경에서 우수한 성능을 보였다. In this paper, we propose a efficient noise power estimation technique for an integrated acoustic echo and noise suppression system in a frequency domain. The proposed method uses speech absence probability (SAP) derived from the microphone input signal as the smoothing parameter updating noise power to reduce the noise power estimation error resulted from the distortions in the unified structure where the noise suppression (NS) operation is placed after the acoustic echo suppression (AES) algorithm. Therefore, in the proposed approach, the smoothing parameter based on SAP derived from the input signal instead of echo-suppressed signal should stop updating noise power estimates during the distorted noise spectrum periods. The performance of the proposed algorithm is evaluated by the objective test under various environments and yields better results compared with the conventional scheme.