• Journal of Korean Society of Disaster and Security
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• v.13 no.1
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• pp.1-11
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• 2020

One of the important problem in statistical hydrology is to estimate the appropriated probability distribution for a given sample data. For the problem, a goodness-of-fit test is conducted based on the similarity between estimated probability distribution and assumed theoretical probability distribution. Probability plot correlation coefficient test (PPCC) is one of the goodness-of-fit test method. PPCC has high rejection power and its application is simple. In this study, test statistics of PPCC were derived for generalized extreme value distribution (GEV) models based on L-moments and these statistics were suggested by the multiple and nonlinear regression equations for its usability. To review the rejection power of the newly proposed method in this study, Monte Carlo simulation was performed with other goodness-of-fit tests including the existing PPCC test. The results showed that PPCC-A test which is proposed in this study demonstrated better rejection power than other methods, including the existing PPCC test. It is expected that the new method will be helpful to estimate the appropriate probability distribution model.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.39-39
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• 2015

극치 수문(Hydrologic extremes)분야에서는 수문자료의 분포에 따라 Gumbel, GEV, 그리고 GLO 분포와 같은 다양한 확률통계 분포형이 존재한다. GEV와 GLO 분포형의 경우 Gumbel 분포형과 달리 형상매개변수가 포함된 3변수 분포형으로써 이상 기후 현상으로 인한 잦은 극치 수문사상을 표현하는데 좀 더 유연한 것으로 알려져 있다. 특히 GLO 분포형의 경우 영국에서 홍수빈도해석 시 적정분포형으로 선정된바 있다(Institute of Hydrology, 1999). 다양한 분포형 중에서 표본 자료를 대표할 수 있는 분포형을 선정하는 통계적 기법이 적합도 검정이다. 적합도 검정에는 $x^2$-검정, Cramer von-Mises 검정, Kolmogorov-Smirnov 검정, PPCC(probability plot correlation coefficient, 확률도시 상관계수)검정 등이 있으며 그 중 PPCC 검정은 이용방법이 간편하면서도 뛰어난 기각능력을 보이는 것으로 알려져 있다. 본 연구에서는 극치 수문분야에서 널리 이용되고 있는 GLO 분포형을 대상으로 자료의 왜곡도 영향을 고려할 수 있는 확률도시 상관계수 검정의 검정통계량을 추정하여 보았다.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.635-639
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• 2004

댐과 같은 구조물의 설계시 큰 강우량에 내한 분포함수의 적합성을 놀일 필요가 있다. 이에 대해 Wang (1997a and b)은 큰 설계량에 내한 적합성을 놀이기 위해 LH 모멘트와 고차 PWM(higher Probability Weighted Moments)방법을 제안하였다. 따라서 본 연구에서는 우리나라의 자 지역별로 대표적인 4개 지점의 일 강우량 자료를 사용하여 제안된 고차 PWM 방법의 적용성을 살펴보았다. 그 과정으로 가장 낮은 차수인 일반적인 PWM 방법과 더 높은 차수의 PWM 방법을 이용하여, GEV(Generalized Extreme Value) 분포와 Gumbel 분포에 대한 매개변수를 추정한 후 이 추정치를 확률지에 실측치와 함께 도시하여 결과를 비교하였다. 그리고 PPCC(Probability Plot Correlation Coefficient) 적합도 검정결과를 통해 추정된 매개변수의 적합성을 확인하였다.

• Korean Journal of Biological Psychiatry
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• v.21 no.4
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• pp.168-174
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• 2014

Objectives Sensory gating dysfunctions in patients with schizophrenia and bipolar disorder have been investigated through two similar methods ; P50 suppression and prepulse inhibition paradigms. However, recent studies have demonstrated that the two measures are not correlated but rather constitute as distinct neural processes. Recent studies adopting spectral frequency analysis suggest that P50 suppression reflects the interaction between gamma and other frequency bands. The aim of the present study is to investigate which frequency component shows more significant interaction with gamma band. Methods A total of 108 mood disorder patients and 36 normal subjects were included in the study. The P50 responses to conditioning and test stimuli with an intra-pair interval of 500 msec were measured in the study population. According to P50 ratio (amplitude to the test stimulus/amplitude to the conditioning stimulus), the subjects with P50 ratio less than 0.2 were defined as suppressed group (SG) ; non-suppressed group (NSG) consisted of P50 ratio more than 0.8. Thirty-five and 25 subjects were included in SG and NSG, respectively. Point-to-point correlation coefficients (PPCCs) of both groups were calculated between two time-windows : the first window (S1) was defined as the time-window of one hundred millisecond after the conditioning auditory stimulus and the second window (S2) was defined as the time-window of 100 msec after the test auditory stimulus. Spectral frequency analysis was performed to investigate which frequency band results in the difference of PPCC between SG and NSG. Results Significant reduction of PPCC between S1 and S2 was observed in the SG (Pearson's r = 0.24), compared to PPCC of the NSG (r = 0.58, p < 0.05). In spectral frequency analysis, gamma band showed "phase-reset" and similar responses after the two auditory stimuli in suppressed and non-suppressed group. However in the case of alpha band, comparison showed significantly low PPCC in SG (r = -0.14) compared to NSG (r = 0.36, p < 0.05). This may be reflecting "phase-out" of alpha band against gamma band at approximately 50 msecs after the test stimulus in the SG. Conclusions Our study suggests that normal P50 suppression is caused by phase-out of alpha band against gamma band after the second auditory stimulus. Thus it is demonstrated that normal sensory gating process is constituted with attenuated alpha power, superimposed on consistent gamma response. Implications of preserved gamma and decreased alpha band in sensory gating function are discussed.

• Proceedings of the Korea Water Resources Association Conference
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• 2009.05a
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• pp.1321-1326
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• 2009

강우는 수자원 확보 측면에서 근원이 되는 요소이다. 그러므로 정확한 확률강우량 산정은 미래의 가용 수자원량을 예측하는데 있어 중요한 사항중 하나이며 무엇보다 신중한 결정이 요구된다. 또한 하천의 범람에 의한 침수를 예방하는 수공구조물 등의 설계에 있어서는 신뢰할 수 있는 확률강우량 산정이 선행되어야 한다. 본 연구에서는 최근 우리나라 극치강우확률분포로서 많은 연구가 이루어지고 있는 GEV 분포(GEV-O)를 기반으로 위치 매개변수에 시간의 함수를 고려한 개선된 GEV 분포(GEV-A)를 이용하여 서울지점에 적용함으로서 GEV-O 분포에 의한 확률강우량과 GEV-A 분포로 산정된 확률강우량을 비교 검토하였다. 먼저 임의의 난수 발생을 통해 최우도추정법과 확률가중모멘트법으로 매개변수를 추정한 GEV-O 분포와 최우도추정법으로 매개변수를 추정한 GEV-A 분포의 상대평균제곱근오차 (R-RMSE)를 계산하여 비교함으로서 GEV-A 분포의 효율성을 판단하였다. 사례연구는 1961년부터 2008년까지 서울강우관측소에서 측정된 연최대 1일 강우량으로 하였으며 $X^2$-검정, PPCC-검정으로 적합도 검정을 실시하였다. 강우빈도분석 결과 GEV-A 분포가 GEV-O 분포로 산정된 결과 보다 대체로 재현기간 200년 이상일 경우, 과다 산정되는 경향을 보였다. 추후 개선된 GEV 분포를 서울 인근 지점에 적용함으로서 지역빈도해석(Regional Frequency Analysis)을 실행하기 위한 연구가 진행되어야 할 것이다. 또한 확률홍수량 산정 등에도 개선된 GEV 분포를 이용함으로서 보다 정확하고 신뢰성 있는 확률수문량을 예측하여야 할 것이다.

• Journal of Korea Water Resources Association
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• v.42 no.10
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• pp.857-866
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• 2009

In this study, basic data is consisted annual maximum rainfall at 56 stations that has the rainfall records more than 30years in Korea. The 14 probability distributions which has been widely used in hydrologic frequency analysis are applied to the basic data. The method of moments, method of maximum likelihood and probability weighted moments method are used to estimate the parameters. And 4-tests (chi-square test, Kolmogorov-Smirnov test, Cramer von Mises test, probability plot correlation coefficient (PPCC) test) are used to determine the goodness of fit of probability distributions. This study emphasizes the necessity for considering the variability of the estimate of T-year event in hydrologic frequency analysis and proposes a framework for evaluating probability distribution models. The variability (or estimation error) of T-year event is used as a criterion for model evaluation as well as three goodness of fit criteria (SLSC, MLL, and AIC) in the framework. The Jackknife method plays a important role in estimating the variability. For the annual maxima of rainfall at 56 stations, the Gumble distribution is regarded as the best one among probability distribution models with two or three parameters.

• Korean Journal of Pharmacognosy
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• v.35 no.4 s.139
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• pp.288-292
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• 2004

To evaluate the quality of the crude drugs using three kinds of Cinnamomum Cortex (CC), Vietnamese CC (VCC, the stem bark of Cinnamomum obtusifolium), periderm-peeled Chinese CC (PPCC, periderm-peeled stem bark of C. cassia), Chinese CC (CCC, stem bark of C. cassia) and a Cinnamomi Ramulus (CR, the twig of C. cassia), the four essential oils were prepared by steam distillation method. Cinnamaldehdye (CAN) and an unknown substance tentatively named hydroxy-cinnamaldehdye(HCNA) were detected in the four essential oils by gas chromatography-mass spectrometry, the contents of which are significantly different one another. Vietnamese CC had the highest content of HCNA whereas CR had the highest CAN content and the lowest HCNA. Vietnamese CC exhibited the greatest cytotoxic activity against the cancer cell lines, A549, HepG-2, HL-60, P-388, U-937, and KB and CR the lowest cytotoxicity. Contents of CAN and HCNA in CCC and PPCC are positioned between VCC and CR. These results suggest that measurement of HCNA and cytotoxicity may determine the quality of CC and CR.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.697-700
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• 2006

저수시 하천유량(Low Streamflow)의 추정은 하천의 수질관리, 용수공급계획, 댐 방류계획등의 수자원관리에 있어서 매우 중요한 부분이다. 이러한 중요성에 따라 Vogel과 Kroll (1989)은 저수시 하천유량을 추정하기 위한 여러 가지 확률분포함수를 제안하였다. 가장 흔히 제안되어지는 이변수 확률분포(Two-Parameter Distribution)로는 Lognormal 분포와 Weibull 분포가 있으며 이와 더불어 Three-Parameter Lognormal, Three-Parameter Weibull, Log Person Type Ⅲ 분포도 널리 사용되어진다. 그러나 이러한 여러 가지 확률 분포함수 중에서 가장 적절한 확률분포의 선택은 저수시 하천유량의 물리적인 측면과는 상관없이 주로 적합도(Gooness of Fit)에 기인된 통계치에 의해서만 결정되기도 하는데 이러한 경우 잘못된 가정을 받아들이는 확률이 높아짐에 따라 추정결과의 신뢰성(Reliability)을 감소시킬 수 있다. 이러한 문제점을 극복하기 위해서 Onoz와 Bayazit (2001)는 Recession Curve를 지수함수로 가정하고 최대 갈수 기간의 길이(Maximum Dry Period Length)의 확률에 대한 이론적인 결과치들을 사용하여 Weibull 분포의 특정한 경우에 해당되어지는 Power 분포를 유도하였으며 유도된 Power 분포의 매개변수를 추정하기 위하여 L-Moment 방법을 사용하였다. 또한 Onoz와 Bayazit (2001) 작은 유출량에서 확률분포와 잘 맞지 않는 경우 작은 유출량값에 작은 가중치를 부여하여 확률분포에 대한 영향을 줄이는 방법인 LL-Moment 방법을 제안하였다. 본 연구에서는 낙동강 유역의 1번부터 5번 소유역에 대해 SSARR 모형을 이용하여 모의한 유출량을 이용하여 Weibull 분포, L-Moment방법에 의해 추정된 매개변수를 사용한 Power 분포, LL-Moment 방법에 의해 추정된 매개변수를 사용한 Power 분포를 적용하였으며 이들 분포의 적합도를 PPCC Test를 사용하여 평가해봄으로써 낙동강 유역에서의 저수시의 유출량 추정에 대한 Power 분포의 적용성을 판단해 보았다.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3172-3179
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• 2011

Several materials using polymer-portland-cement concrete have developed to have not only strength of attachment with body, but also waterproof function and strong anti-sodium chloride properties. Especially, in case of railway, unlike other public transportation, it is very difficult to doing the repair and reinforcement work of structure during service time. Therefore, the development and study of materials having characteristics of structural strength, unification behavior with body, and resistance of crack are very important. Accordingly, the characteristic of material of polymer based concrete is indicated compared with the experiment and analysis through this study, and suggested application to railway tunnel, bridge, and concrete track structure.

• Journal of the Korean earth science society
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• v.33 no.1
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• pp.39-48
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• 2012

In this study, a statistical estimation of probable precipitation and an analysis of its return period in Busan were performed using long-term precipitation data (1973-2007) collected from the Busan Regional Meteorological Administration. These analyses were based on the method of probability weighted moments for parameter estimation, the goodness-of-fit test of chi-square ($x^2$) and the probability plot correlation coefficient (PPCC), and the generalized logistics (GLO) for optimum probability distribution. Moreover, the spatial distributions with the determination of probable precipitation were also investigated using precipitation data observed at 15 Automatic Weather Stations (AWS) in the target area. The return periods for the probable precipitation of 245.2 and 280.6 mm/6 hr with GLO distributions in Busan were estimated to be about 100 and 200 years, respectively. In addition, the high probable precipitation for 1-, 3-, 6-, and 12-hour durations was mostly distributed around Dongrae-gu site, all coastal sites in Busan, Busanjin and Yangsan sites, and the southeastern coastal and Ungsang sites, respectively.