• International Journal of Reliability and Applications
• /
• 제14권1호
• /
• pp.27-39
• /
• 2013

In this article, a new model based on the Rayleigh distribution is introduced. This model is useful and practical in physics, reliability, and life testing. The statistical and reliability properties of this model are presented, including moments, the hazard rate, the reversed hazard rate, and mean residual life functions, among others. In addition, it is shown that the distributions of the new model are ordered regarding the strongest likelihood ratio ordering. Four estimating methods, namely, method of moment, maximum likelihood method, Bayes estimation, and uniformly minimum variance unbiased, are used to estimate the parameters of this model. Simulation is used to calculate the estimates and to study their properties. Finally, the appropriateness of this model for real data sets is shown by using the chi-square goodness of fit test and the Kolmogorov-Smirnov statistic.

• Structural Engineering and Mechanics
• /
• 제17권1호
• /
• pp.29-50
• /
• 2004

A total life model was developed to assess the service life of aging aircraft. The primary focus of this paper is the development of crack growth life projection using the response surface method. Crack growth life projection is a necessary component of the total life model. The study showed that the number of load cycles N needed for a crack to propagate to a specified size can be linearly related to the geometric parameter, material, and stress level of the component considered when all the variables are transformed to logarithmic values. By the Central Limit theorem, the ln N was approximated by Gaussian distribution. This Gaussian model compared well with the histograms of the number of load cycles generated from simulated crack growth curves. The outcome of this study will aid engineers in designing their crack growth experiments to develop the stochastic crack growth models for service life assessments.

• Journal of the Korean Data and Information Science Society
• /
• 제25권6호
• /
• pp.1521-1530
• /
• 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.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제54권4호
• /
• pp.188-194
• /
• 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.

• 지역사회간호학회지
• /
• 제31권3호
• /
• pp.310-321
• /
• 2020

Purpose: The purpose of this study is to evaluate the effectiveness of the interpersonal caring program for young North Korean defectors which we developed based on Kim's interpersonal caring technique. Methods: This study employs a non-equivalent control group pretest-posttest design. The subjects of this study are 36 young North Korean defectors living in three areas. The participants are recruited through alternative schools, churches, and acquaintances. The experimental group consists of 20 participants and the control group consists of 16 participants. Experiments are conducted by four days. Specifically, the experiments are conducted eight times and each takes about 120 minutes. Furthermore, we run the camp for two nights and three days. We test our hypothesis by using Kolmogorov-Smirnov, Independent t-test, Paired t-test, and Independent t-test. Results: All the test statistics support our hypotheses such as self-esteem (t=1.87, p=.035), mental health (t=-1.69, p=.049), interpersonal relationships (t=1.93, p=.031), and quality of life (t=1.88, p=.034). Conclusion: We found that the interpersonal caring program developed in this study is effective in improving North Korean defectors' self-esteem, mental health, interpersonal relationships, and quality of life.

• Journal of the Korean Data and Information Science Society
• /
• 제26권3호
• /
• pp.569-580
• /
• 2015

두 집단의 생존분포의 비교를 위한 방법으로는 로그-순위 검정법이 널리 쓰이고 있다. 그러나 이는 두 집단의 생존분포 간에 비례위험모형 가정이 성립하는 경우에 적합한 것으로써, 두 집단의 생존분포가 교차하는 상황 하에서는 해당 검정법의 유효성을 장담할 수 없다. 그러나 두 집단의 생존분포가 교차하는 상황은 빈번히 발생하며, 이 같은 상황에서 두 생존분포의 동일성 검정을 위한 여러 연구가 진행되어왔다. 본 논문에서는 두 집단 간 생존분포가 교차하는 상황 하에서의 동일성 검정을 위한 방법들을 고려한다. 나아가 교차하는 상황을 위치에 따라 세분화하고 모의실험을 통해 각 상황에서 다양한 검정법들의 검정력을 비교하였으며, 그 결과를 토대로 주어진 상황에서 적절한 방법의 선택에 유용한 정보를 제공하고자 한다.

• 한국전문물리치료학회지
• /
• 제26권1호
• /
• pp.60-66
• /
• 2019

Background: Knee osteoarthritis (OA) is a single most arthritic disease. Knee joint space width (JSW) is commonly used for grading severity of knee OA. However, previous studies did not established criterion validity and test-retest reliability of ultrasound (US) image for measuring JSW. Objects: The aim of this study was to establish criterion validity and test-retest reliability of US measurement of medial and lateral knee JSW. Methods: Twenty-nine subjects with knee OA were participated. The US and X-ray were used to measure knee JSW. One sample Kolmogorov-Smirnov test was used to confirm the data normal distribution. Pearson correlation coefficient and ICC were used to calculated and establish criterion validity and test-retest reliability, respectively. Results: US measurement of medial and lateral knee JSW was highly correlated with radiographic imaging measure (r=.714 and .704, respectively). Test-retest reliabilities of medial and lateral knee JSW were excellent correlated (ICC=.959 for medial side and .988 for lateral side, respectively). Conclusion: US may be valid tool to measure knee JSW.

• 대한원격탐사학회지
• /
• 제29권4호
• /
• pp.361-373
• /
• 2013

공간해상도 약 1 m의 고해상도 X-band SAR 위성이 이용되면서 SAR를 이용한 도심지 모니터링, 표적탐지, 건물 재구성에 관한 연구가 진행되고 있다. 본 연구에서는 고해상도 TerraSAR-X SAR 영상을 이용한 도심지 건물 재구성을 수행하였다. 도심지 건물 재구성을 위하여 1:25,000 수치지형도로부터 건물의 외곽선을 추출하였으며, 추출한 건물의 외곽선을 기반으로 SAR 영상에서 모서리반사 위치를 찾았다. KS 테스트(Kolmogorov-Smirnov Test)에 기반하여 고해상도 SAR 진폭영상의 건물 모서리반사 위치로부터 레이오버 길이를 측정하여 건물의 초기 높이를 설정하였다. 진폭영상을 이용하여 추출한 건물의 초기 높이 기준 -10 m에서 +10 m로 건물의 높이를 변화시키며 도심지에 적합한 간섭위상 시뮬레이션을 수행하여 TerraSAR-X 간섭위상과의 위상 일치성 계산을 하였다. 위상 일치의 경향성 분석을 통해 건물의 높이를 설정해 줌으로써 고해상도 SAR 영상을 이용한 도심지 건물 재구성 연구를 진행하였다. 대전지역의 아파트 단지에 적용한 결과, 진폭영상과 간섭위상을 이용하여 추정된 건물 높이는 LiDAR로부터 추출된 높이를 기준으로 약 1~2 m 정도의 RMSE (Root Mean Square Error)를 보였다. 개발된 알고리즘은 향후 TerraSAR-X와 TanDEM-X 간섭쌍 자료에 적용할 경우, 보다 도심지 모니터링에 효과적으로 이용될 수 있을 것이다.

• Journal of Plant Biology
• /
• 제24권1호
• /
• pp.47-57
• /
• 1981

1979년 및 1980년에 경기도 광릉과 양주군 수동면에서 저적면적계의 빈도분포의 skewness와 kurtosis를 검정하기 위하여 총 46개의 단일종 조림지에서 개목의 주변장을 흉고에서 재었다. 이들 조림지는 10~50년된 것이며 수종은 잣나무, 낙엽송, 전나무 및 리기다소나무이다. 각 지소에서의 측정수는 70~110이며 저적면적계의 수는 Sturge의 방식에 따랐으며, 5~10계였다. 수동에 있어서 나이(년)와 개목 저적면적($\textrm{cm}^2$)은 각각 10~20 및 27.60~383이었으며, 광릉에서는 15~47 및 102.15~619.14이었다. 한 곳을 제외하고 모든 곳에서 +g$_1$값을 나타냈고, 6개소를 제외하고는 그 값이 0.3~2.2였다. 23곳에서는 유의한 +g$_1$값을 나타냈다. 이들의 저적면적계수는 6~9였다. 이상의 사실은 종내경쟁이 약 10년된 조림지에서도 시작되며 약 50년까지도 계속됨을 시사한다. 24개소에서 -g$_2$값을 나타내며 이들의 값은 -0.12~-0.83의 범위였다. 약 20곳에서는 +g$_2$값을 나타냈으며 그 범위는 +0.13~+3.841이었다. 22개의 +g중 11채는 매우 유의한 것이었다. 단지 5만이 유의한 Kolmogorov-Smirnov 검정결과를 나타냈다. 4종중 낙엽송이 가장 나이 어린 시절에 종내경쟁을 시작하고 그 다음이 전나무 그리고 잣나무의 순으로 경쟁을 시작하는 것 같다. 이 자료는 저적면적계의 빈도분포를 통하여 종내경쟁을 탐지하고자 할 때 적정 계(급)수는 12이상이 아니고 6~9이며 적정 관측목수는 100이상이 아니고 약 80임을 시사한다. 필자는 저적면적의 빈도분포가 종내경쟁이 있을 때에는 bimodal 분포라기 보다는 trimodal 분포를 나타내고 있다고 생각하며 또한 종내경쟁이 약화되어 저적면적빈도분포가 정상분포 단계에 도달되기 전에 바로 platykurtic분포로 되는 것이 아니고 leptokurtic 분포적 단계를 거친다고 본다

• 한국산업보건학회지
• /
• 제1권1호
• /
• pp.47-55
• /
• 1991

Exposure level of respirable coal dust of underground coal mines in Taebaek area was evaluated. Personal air samplers with 10-mm nylone cyclones were attached to the coal workers including drillers, coal cutters, their assistants, haulers, and separators. Log-normality of respirable dust exposure concentration were tested by Kolmogorov-Smirnov one-sample test. Differences of means of respirable dust exposure concentration between work sites were tested by one-way ANOVA test and multiple comparison(Scheffe) test. And differences of respirable dust exposure concentration of principal and assistant workers in drilling sites and in coal faces were tested by paired t-test. Relation of respirable dust exposure concentration for the principal workers and their assistants in drilling sites and in coal faces were tested by regression analysis. The results were as follows : 1. All of the respirable dust concentration were log-normally distributed. 2. There were not only significantly different means of exposure concentration between drillers and coal cutters but between coal cutters and haulers. 3. Means of exposure concentration of drillers and drilling assistants were not significantly different. And means of exposure concentration of coal cutters and coal cutting assistants were not different.