• Title/Summary/Keyword: Kolmogorov-smirnov

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Alternative accuracy for multiple ROC analysis

  • Hong, Chong Sun;Wu, Zhi Qiang
    • Journal of the Korean Data and Information Science Society
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    • v.25 no.6
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    • pp.1521-1530
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    • 2014
  • The ROC analysis is considered for multiple class diagnosis. There exist many criteria to find optimal thresholds and measure the accuracy of diagnostic tests for k dimensional ROC analysis. In this paper, we proposed a diagnostic accuracy measure called the correct classification simple rate, which is defined as the summation of true rates for each classification distribution and expressed as a function of summation of sequential true rates for two consecutive distributions. This measure does not weight accuracy across categories by the category prevalence and is comparable across populations for multiple class diagnosis. It is found that this accuracy measure does not only have a relationship with Kolmogorov - Smirnov statistics, but also can be represented as a linear function of some optimal threshold criteria. With these facts, the suggested measure could be applied to test for comparing multiple distributions.

Photovoltaic System Output Forecasting by Solar Cell Conversion Efficiency Revision Factors (태양전지 변환효율 보정계수 도입에 의한 태양발전시스템 발전량 예측)

  • Lee Il-Ryong;Bae In-Su;Shim Hun;Kim Jin-O
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.54 no.4
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    • pp.188-194
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    • 2005
  • There are many factors that affect on the system output of Photovoltaic(PV) power generation; the variation of solar radiation, temperature, energy conversion efficiency of solar cell etc. This paper suggests a methodology for calculation of PV generation output using the probability distribution function of irradiance, PV array efficiency and revision factors of solar cell conversion efficiency. Long-term irradiance data recorded every hour of the day for 11 years were used. For goodness-fit test, several distribution (unctions are tested by Kolmogorov-Smirnov(K-S) method. The calculated generation output with or without revision factors of conversion efficiency is compared with that of CMS (Centered Monitoring System), which can monitor PV generation output of each PV generation site.

Frequency Analysis of Extreme Rainfall Using 3 Parameter Probability Distributions (3변수 확률분포형에 의한 극치강우의 빈도분석)

  • Kim, Byeong-Jun;Maeng, Sung-Jin;Ryoo, Kyong-Sik;Lee, Soon-Hyuk
    • Journal of The Korean Society of Agricultural Engineers
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    • v.46 no.3
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    • pp.31-42
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    • 2004
  • This research seeks to derive the design rainfalls through the L-moment with the test of homogeneity, independence and outlier of data on annual maximum daily rainfall at 38 rainfall stations in Korea. To select the appropriate distribution of annual maximum daily rainfall data by the rainfall stations, Generalized Extreme Value (GEV), Generalized Logistic (GLO), Generalized Pareto (GPA), Generalized Normal (GNO) and Pearson Type 3 (PT3) probability distributions were applied and their aptness were judged using an L-moment ratio diagram and the Kolmogorov-Smirnov (K-S) test. Parameters of appropriate distributions were estimated from the observed and simulated annual maximum daily rainfall using Monte Carlo techniques. Design rainfalls were finally derived by GEV distribution, which was proved to be more appropriate than the other distributions.

Goodness of Fit Test of Normality Based on Kullback-Leibler Information

  • Kim, Jong-Tae;Lee, Woo-Dong;Ko, Jung-Hwan;Yoon, Yong-Hwa;Kang, Sang-Gil
    • Communications for Statistical Applications and Methods
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    • v.6 no.3
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    • pp.909-918
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    • 1999
  • Arizono and Ohta(1989) studied goodness of fit test of normality using the entropy estimator proposed by Vasicek (1976) Recently van Es(1992) and Correa(1995) proposed an estimator of entropy. In this paper we propose goodness of fit test statistics for normality based on Vasicek ven Es and Correa. And we compare the power of the proposed test statistics with Kolmogorov-Smirnov Kuiper Cramer von Mises Watson Anderson-Darling and Finkelstein and Schefer statistics.

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Photovoltaic Generation System Output Forecasting using Irradiance Probability Distribution Function (일사량 확률분포함수를 이용한 태양광 발전시스템 발전량 예측)

  • Lee Il Ryong;Bae In Su;Jung Chang Ho;Kim Jln O;Shim Hun
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.548-550
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    • 2004
  • This paper suggests a methodology for calculation of photovoltaic(PV) generation system output using probability distribution function, PV way efficiency and PV system design Parameters. Long term irradiance recorded for every hour of the day for 11 years were used. For goodness-fit test, several distribution functions are tested by Kolmogorov- Smirnov(K-S) test. And the calculated generation output is compared with that of CMS(Centered Monitoring System), which can monitoring PV generation output of each PV generation site.

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Estimation of p-values with Two Dimensional Null Distributions from Genomic Data Set

  • Yee, Jaeyong;Park, Mira
    • Journal of the Korean Data Analysis Society
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    • v.20 no.6
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    • pp.2711-2719
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    • 2018
  • When an observable is described by a single value, the statistic significance may be estimated by construction of null distribution using permutation and counting the portion of it that exceeds the observed value by chance. Genome-wide association study usually focuses on the association measure between a single or interacting genotypes with a single phenotype. However investigation of common genotypes associated simultaneously on multiple phenotypes may involve the observables that should be described with multiple numbers. Statistical significance for such an observable would involve null distribution in multiple dimensions. In this study, extension of the p-value estimation process using null distribution in one dimension has been sought that may be applicable to two dimensional case. Comparison of the position of points within the set of points they form has been proposed to use a positioning parameter inspired by the extension of the Kolmogorov-Smirnov statistic to two dimensions.

Comparison of Differences in Levels per Group on Math Self-Regulated Learning Factors of High School Students (고등학생의 수학 자기조절 학습 요인에 대한 집단별 수준 차이 비교)

  • Yoo, Ki Jong
    • Journal for History of Mathematics
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    • v.34 no.1
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    • pp.21-37
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    • 2021
  • The purpose of the present study is to compare the differences in levels per group of high school students regarding the self-regulated learning factors for mathematics. For this purpose, a self-regulated learning measurement tool was developed and surveys were conducted. And the statistical analysis was completed using the frequency analysis, Kolmogorov-Smirnov normality test, Mann-Whitney U test and the Kruskal-Wallis H test. As a result, it is found that self-efficacy is of statistically significant differences in self-regulated learning levels regardless of the group classifications but test anxiety does not show statistically significant differences in self-regulated learning levels regardless of the group classifications.

A Consideration on Intraspecific Competition with Particular Reference to Basal Area-class Structure of Even-aged Coniferous Monocultures (침엽수 동령 인공림내 개목들의 저적면적빈도분포에 의거한 종내경쟁에 대한 고찰)

  • 오계칠
    • Journal of Plant Biology
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    • v.24 no.1
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    • pp.47-57
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    • 1981
  • Girth at breast height was measured to test skewness ($g_1$) and kurtosis ($g_2$) of frequency distribution of the basal area in terms of t-test and Kolmogorov-Smirnov test for a total of forty six monocultures within Sudong and Kwhangnung area in central part of Korean peninsula in 1979 and 1980. The monocultures are about 10 to 50 years old, and four kinds: Pinus koraiensis, Larix kaempferi, Abies holophylla and Pinus rigida. Most of the sample sizes per site were ranged 70 to 110 excluding 4 sites. The number of classes interval was based on Sturges rule for each monoculture and was ranged from 5 to 10. In Sudong the range of age(yr) and basal area (($cm^2$)/tree) of the monocultures were from 10 to 20 and from 27.60 to 383. for Kwhangnung they were from 15 to 47 and mostly 102.15 to 619.14, respectively. All 43 monocultures except 1 showed +$g_1$, which ranged from 0.3 to 2.2 except six sites. Of the total 46 sites, 23 sites showed significant +$g_1$ which includes about 10 year-old monoculture. The number of classes interval with significant positive skewness ranged from 6 to 9. The data suggest that intraspecific competition in terms of stand structure seems to appear from about 10 year-old monocultures, and it may even last to about 50 year-old one. Around 24 monocultures showed nonsignificant -$g_2$ except one. Most -$g_2$ ranged from -0.12 to -0.83. Around 20 monocltures showed positive $g_2$ ranging from +0.13 to +3.841. Of the 22 +$g_1$, majority of 11 were very highly significant. Of all monocultures only 5 showed significant result from Kolmogorov-Smirnov test. Of the 4 species, Larix kaempferi seems to show density stress first then Abies holophylla, and Pinus koraiensis last. Data of this study indicate that adequate number of classes intervals and sample sizes for studying intraspecific competition in terms of basal area are 6 to 9 and 80 trees rather than 12 and 100 trees, respectively. It also suggests that most of the frequency distribution of basal area class are trimodal rather than bimodal under density stress. It is proposed that the leptokurtic distribution appears before normal distribution rather than direct change from platykurtic to normal distribution of basal area for selected stages in the development of stands.

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A Study on Comparison and Classification of Response Time of Mobile Portals (모바일 포털들의 응답시간 비교 및 분류에 관한 연구)

  • Ryu, Gui-Yeol
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.3
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    • pp.1-7
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    • 2018
  • The purpose of this study is to compare and analyze the response time of three mobile portal sites in Korea using distributions. The research subjects are the mobile portal site of Naver, Daum, and Nate. The experiment period is six years from April 18, 2012 when mobile portals started to activate, to April 17, 2018. The number of experiments is 4,060. Histograms and percentages were used for the distribution comparisons. For the theoretical comparison, Chi-Square test is adopted as a parametric method, and Kolmogorov-Smirnov test is as a nonparametric method. Naver was the fastest of all four methods, the next was Nate, the next was the slowest. The same result was obtained in terms of average response speed. These results are in contradiction to the results of the wired portal. Naver is a strategy to increase the response speed in accordance with the characteristics of media. Daum is a strategy to increase the contents at the cost of response speed. As for classification, we divide the response time into "Comfortable", "Tolerable", "Feedback", "Leave" according to response time. The ratio of more than 7 seconds that users leave called as "Leave" is 1.18% for Naver, 11.70% for Daum, and 1.5% for Nate. As Daum is overwhelmingly high, the response time is very much in need of improvement. In addition, we show the response time of three mobile portals needs to be reduced We hope that the results of this paper will facilitate technology competition to increase the response speed of mobile portals.

Flight Technical Error Modeling for UAV supported by Local Area Differential GNSS (LADGNSS 항법지원을 받는 무인항공기의 비행 기술 오차 모델링 기법)

  • Kim, Kiwan;Kim, Minchan;Lee, Dong-Kyeong;Lee, Jiyun
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.43 no.12
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    • pp.1054-1061
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    • 2015
  • Navigation accuracy, integrity, and safety of commercial Unmanned Aerial Vehicle (UAV) is becoming crucial as utilization of UAV in commercial applications is expected to increase. Recently, the concept of Local-Area Differential GNSS (LADGNSS) which can provide navigation accuracy and integrity of UAV was proposed. LADGNSS can provide differential corrections and separation distances for precise and safe operation of the UAV. In order to derive separation distances between UAVs, modeling of Flight Technical Error (FTE) is required. In most cases, FTE for civil aircraft has been assumed to be zero-mean normal distribution. However, this assumption can cause overconservatism especially for UAV, because UAV may use control and navigation equipments in wider performance range and follow more diverse path than standard airway for civil aircraft. In this research, flight experiments were carried out to understand the characteristics of FTE distribution. Also, this paper proposes to use Johnson distribution which can better describe heavy-tailed and skewed FTE data. Futhermore, Kolmogorov-Smirnov and Anderson-Darling tests were conducted to evaluate the goodness of fit of Johnson model.