• Title/Summary/Keyword: kolmogorov-smirnov test

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Exponentiality Test of the Three Step-Stress Accelerated Life Testing Model based on Kullback-Leibler Information

  • Park, Byung-Gu;Yoon, Sang-Chul;Lee, Jeong-Eun
    • Journal of the Korean Data and Information Science Society
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    • v.14 no.4
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    • pp.951-963
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    • 2003
  • In this paper, we propose goodness of fit test statistics based on the estimated Kullback-Leibler information functions using the data from three step stress accelerated life test. This acceleration model is assumed to be a tampered random variable model. The power of the proposed test under various alternatives is compared with Kolmogorov-Smirnov statistic, Cramer-von Mises statistic and Anderson-Darling statistic.

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The Exposure Level of Respirable Dust of Underground Coal Mines in Taebaek Area (태백지역 석탄광산의 호흡성 분진 폭로 농도)

  • 윤영노;이정주
    • Journal of Korean Society for Atmospheric Environment
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    • v.4 no.1
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    • pp.23-32
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    • 1988
  • The exposure level of respirable dust and silica for the coal workers of underground coal mines in Taebaek area was evaluated. Personal air samplers were attached to the coal workers-drillers, coal cutters, their helpers, haulers, and separators. Normality and lognormality of respirable dust and silica concentrations were tested by Kolmogorov-Smirnov one-sample test, differences of means of respirable dust and silica concentration were tested by group-t-test and paired t-test, and relation between respirable dust and silica concentration were tested by regression test.

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Edge Detection using Statistical Hypothesis Testing

  • Lim, Dong-Hoon;Sung, Sin-Hee
    • Communications for Statistical Applications and Methods
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    • v.6 no.3
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    • pp.893-900
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    • 1999
  • We use statistical tests which are useful for two-sample problem for detecting edges in gray-level images. An edge is detected by examining changes in gray-level value between adjacent pixel neighborhoods. Some experimental results show that nonparametric detectors such as Mann-Whitney test median test and Kolmogorov-Smirnov test perform effectively in both noisy and noise-free images while parametric T test is sensitive to noise.

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Prediction of Stand Volume and Carbon Stock for Quercus variabilis Using Weibull Distribution Model (Weibull 분포 모형을 이용한 굴참나무 임분 재적 및 탄소저장량 추정)

  • Son, Yeong Mo;Pyo, Jung Kee;Kim, So Won;Lee, Kyeong Hak
    • Journal of Korean Society of Forest Science
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    • v.101 no.4
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    • pp.599-605
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    • 2012
  • The purpose of this study is to estimate diameter distribution, volume per hectare, and carbon stock for Quercus variabilis stand. 354 Quercus variabilis stands were selected on the basis of age and structure, the data and samples for these stands are collected. For the prediction of diameter distribution, Weibull model was applied and for the estimation of the parameters, a simplified method-of-moments was applied. To verify the accuracy of estimates, models were developed using 80% of the total data and validation was done on the remaining 20%. For the verification of the model, the fitness index, the root mean square error, and Kolmogorov-Smirnov statistics were used. The fitness index of the site index, height, and volume equation estimated from verification procedure were 0.967, 0.727, and 0.988 respectively and the root mean square error were 2.763, 1.817, and 0.007 respectively. The Kolmogorov-Smirnov test applied to Weibull function resulted in 75%. From the models developed in this research, the estimated volume and above-ground carbon stock were derived as $188.69m^3/ha$, 90.30 tC/ha when site index and stem number of 50-years-old Quercus variabilis stand show 14 and 697 respectively. The results obtained from this study may provide useful information about the growth of broad-leaf species and prediction of carbon stock for Quercus variabilis stand.

Nonparametric homogeneity tests of two distributions for credit rating model validation (신용평가모형에서 두 분포함수의 동일성 검정을 위한 비모수적인 검정방법)

  • Hong, Chong-Sun;Kim, Ji-Hoon
    • Journal of the Korean Data and Information Science Society
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    • v.20 no.2
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    • pp.261-272
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    • 2009
  • Kolmogorov-Smirnov (K-S) statistic has been widely used for testing homogeneity of two distributions in the credit rating models. Joseph (2005) used K-S statistic to obtain validation criteria which is most well-known. There are other homogeneity test statistics such as the Cramer-von Mises, Anderson-Darling, and Watson statistics. In this paper, these statistics are introduced and applied to obtain criterion of these statistics by extending Joseph (2005)'s work. Another set of alternative criterion is suggested according to various sample sizes, type a error rates, and the ratios of bads and goods by using the simulated data under the similar situation as real credit rating data. We compare and explore among Joseph's criteria and two sets of the proposed criterion and discuss their applications.

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Characteristics of Probability Distribution of BOD Concentration in Anseong Stream Watershed (안성천 유역의 BOD농도 확률분포 특성)

  • Kim, Kyung Sub;Ahn, Taejin
    • Journal of Korean Society on Water Environment
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    • v.25 no.3
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    • pp.425-431
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    • 2009
  • It is very important to know the probability distribution of water-quality constituents for water-quality control and management of rivers and reservoirs effectively. The probability distribution of BOD in Anseong Stream was analyzed in this paper using Kolmogorov-Smirnov test which is widely used goodness-of-fit method. It was known that the distribution of BOD in Anseong Stream is closer to Log-normal, Gamma and Weibull distributions than Normal distribution. Normal distribution can be partially applied depending on significance level, but Log-normal, Gamma and Weibull distributions can be used in any significance level. Also the estimated Log-normal distribution of BOD at Jinwi3 station was to be compared with the measured in 2001, 2002 and 2003 years. It was revealed that the estimated probability distribution of BOD at Jinwi3 follows a theoretical distribution very well. The applicable probability distribution of BOD can be used to explain more rigorously and scientifically the achievement or violation of target concentration in TMDL(Total Maximum Daily Load).

Testing Goodness of Fit in Nonparametric Function Estimation Techniques for Proportional Hazards Model

  • Kim, Jong-Tae
    • Communications for Statistical Applications and Methods
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    • v.4 no.2
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    • pp.435-444
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    • 1997
  • The objective of this study is to investigate the problem of goodness of fit testing based on nonparametric function estimation techniques for the random censorship model. The small and large sample properties of the proposed test, $E_{mn}$, were investigated and it is shown that under the proportional hazard model $E_{mn}$ has higher power compared to the powers of the Kolmogorov -Smirnov, Kuiper, Cramer-von Mises, and analogue of the Cramer-von Mises type test statistic.

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Derivation of Design Flood by Transformation Method(II) - On the non-annual exceedance series- (변환법에 의한 설계홍수량의 유도(II) -비년초과치계열을 중심으로-)

  • 이순혁;맹승진
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.37 no.5
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    • pp.111-118
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    • 1995
  • 첨두유량이 연속적으로 발생하므로 인하여 수리구조물의 파괴에 영향을 끼치는 설계홍수량의 추정을 위해 본 연구에서는 제I보에 이어 2차적으로 부분 기간 계열인 금강, 영산강 및 섬진강 수계 6개 유역의 비년 초과치를 중심으로 하여 변환법인 SMEMAX법, 멱변화(Power Transformation) 및 2단계 멱변환(Two Step Power Transformation, TSPT)법에 의해 빈도분포의 정규화를 시도하고 이들에 대한 정규화 효율성의 비교분석과 설계홍수량 유도를 위한 변환법별 적합도 검정을 수행하였다. 왜곡분포의 정규화 시도는 제I보의 결과와 마찬가지로 SMAMAX 및 Power변환법에서는 빈도분포의 정규화가 미흡하였으나 2단계 멱변환법에서는 빈도분포의 만족한 정규화를 기할 수 있었다. 또한 3개 변환법에 의해 유도된 설계홍수량의 비교 분석에서는 3개 방법 모두 재현기간 20년 이내의 설계홍수량이 거의 유사한 결과를 나타내었으며 Kolmogorov-Smirnov Test에 의한 3개 변환법별 적합도검정 결과 2단계 멱변환법이 적정 변환법으로 인정되었다.

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The Effect of the Problem-Based Learning on Critical Thinking Disposition, Academic Self-Efficacy and Self-Leadership of Nursing Students -Diagnostic Tests and Nursing- (문제중심학습(Problem- Based Learning)이 간호대학생의 비판적 사고성향, 학업적 자기효능감 및 셀프리더십에 미치는 효과 -진단검사와 간호 교과목 중심으로-)

  • Lee, Oi-Sun
    • Journal of Digital Convergence
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    • v.18 no.5
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    • pp.279-285
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    • 2020
  • Purpose :This study intends to test the effects of Problem-based learning on critical thinking disposition, academic self-efficacy and self-leadership for undergraduate nursing students. Methods: A one group pre-post design was applied to four diagnostic test and nursing for 4 times(eight hours) of 26 nursing students. Data were collected between August 29 and December 10, 2019. Data were analyzed by frequencies, Kolmogorov-Smirnov, paried t-test, Wilcoxon signed-rank test using SPSS/WIN 23.0. Results: Problem-based learning was significantly increasing critical thinking disposition(t=-2.16, p=.041) and Academic self-efficacy(z=-2.36, p=.018), but self-efficacy(t=-.16, p=.875) was no significantly. Conclusion: Based on this study, it is suggested that nursing students should develop their core competency by applying problem-based learning to various subject

Accuracy of intraoral scans of edentulous jaws with different generations of intraoral scanners compared to laboratory scans

  • Kontis, Panagiotis;Guth, Jan-Frederik;Schubert, Oliver;Keul, Christine
    • The Journal of Advanced Prosthodontics
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    • v.13 no.5
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    • pp.316-326
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    • 2021
  • PURPOSE. Purpose of this in vitro study was to determine the accuracy of different intraoral scans versus laboratory scans of impressions and casts for the digitization of an edentulous maxilla. MATERIALS AND METHODS. A PEEK model of an edentulous maxilla, featuring four hemispheres on the alveolar ridges in region 13, 17, 23 and 27, was industrially digitized to obtain a reference dataset (REF). Intraoral scans using Cerec Primescan AC (PRI) and Cerec AC Omnicam (OMN), as well as conventional impressions (scannable polyvinyl siloxane) were carried out (n = 25). Conventional impressions (E5I) and referring plaster casts were scanned with the inEOS X5 (E5M). All datasets were exported in STL and analyzed (Geomagic Qualify). Linear and angular differences were evaluated by virtually constructed measurement points in the centers of the hemispheres (P13, P17, P23, P27) and lines between the points (P17-P13, P17-P23, P17-P27). Kolmogorov-Smirnov test and Shapiro-Wilk test were performed to test for normal distribution, Kruskal-Wallis-H test, and Mann-Whitney-U test to detect significant differences in trueness, followed by 2-sample Kolmogorov-Smirnov test to detect significant differences in precision (P < .008). RESULTS. Group PRI showed the highest trueness in linear and angular parameters (P < .001), while group E5I showed the highest precision (P < .001). CONCLUSION. Intraoral scan data obtained using Primescan showed the highest trueness while the indirect digitization of impressions showed the highest precision. To enhance the workflow, indirect digitization of the impression itself appears to be a reasonable technique, as it combines fast access to the digital workflow with the possibility of functional impression of mucosal areas.