• Journal of the Korean Data Analysis Society
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• v.20 no.6
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• pp.2813-2827
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• 2018

Progressive censoring schemes have become quite popular in reliability study. Under progressive censored data, however, some units can be failed between two points of observation with exact times of failure of these units unobserved. For example, loss may arise in life-testing experiments when the failure times of some units were not observed due to mechanical or experimental difficulties. Therefore, multiply progressive censoring scheme was introduced. So, we derives a maximum likelihood estimator of the parameter of exponential distribution. And we introduced the goodness-of-fit test statistics using order statistic and Lorenz curve. We carried out Monte Carlo simulation to compare the proposed test statistics. In addition, real data set have been analysed. In Weibull and chi-squared distributions, the test statistics using Lorenz curve are more powerful than test statistics using order statistics.

• Journal of the Korean Institute of Intelligent Systems
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• v.21 no.1
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• pp.25-28
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• 2011

In this paper, we study some properties of condition for fuzzy data, agrement index by ratio of area and the uniformly most powerful fuzzy test of hypothesis. Also, we suggest a confidence bound for uniformly most powerful fuzzy test. For illustration, we take the most powerful critical fuzzy region from exponential distribution by likelihood ratio and test the hypothesis of ${\chi}^2$-distribution by agreement index.

• Proceedings of the KAIS Fall Conference
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• 2010.11b
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• pp.755-758
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• 2010

본 연구의 목적은 지방 환자의 서울 지역 입원진료의 추이를 파악하고 그 요인을 규명하는 데 있다. 이를 위해 2005년 및 2008년 환자조사 입원자료를 이용하였으며, 서울지역 거주 환자를 제외하고 2005년 333,280명, 2008년 419,873명을 연구대상으로 하였다. 자료분석은 기술통계, 카이제곱 검정, 로지스틱 회귀분석을 실시하였다. 2005년 대비 2008년 성별, 연령별, 의료기관 유형 등 일반적 특성의 분포는 유사한 것으로 나타났다. 지방 환자의 서울지역 이용은 다소 증가한 것으로 나타났으며, 서울 지역 입원진료는 남자, 중장년층 건강보험환자가 타기관에서 의뢰되어 외래를 통해 입원하며, 주 거주지가 경기, 강원, 충북, 충남, 제주지역 순으로, 광역시는 상대적으로 낮았다. 질병군별로는 선천성 기형, 신생물, 종양이나 수술후 추후치료, 눈 질환, 혈액 조혈 면역기 질환, 근골격계 질환 순으로 지방환자의 서울지역 의료기관 입원 이용률이 높았다. 그러나 상대적으로 지방 입원진료 확률이 높은 노년층, 의료급여, 응급경유, 질병군별로 중증도가 높은 환자가 혼재되어 있어 있을 가능성이 있어 향후 중증도 보정에 대한 심층 연구가 필요한 것으로 판단된다.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.11 no.2
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• pp.169-174
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• 2018

In general, the methods of the analysis of variance(ANOVA) for the continuous data and the chi-square test for the discrete data are used for statistical analysis of the effect and the association. In multidimensional data, analysis of hierarchical structure is required and statistical linear model is adopted. The structure of the linear model requires the normality of the data. A multidimensional categorical data analysis methods are used for causal relations, interactions, and correlation analysis. In this paper, Bayesian network model using probability distribution is proposed to reduce analysis procedure and analyze interactions and causal relationships in categorical data analysis.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.102-102
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• 2023

벤포드 법칙(Benford's Law)은 실생활에서 관찰되는 수치 데이터를 첫 자리 숫자에 따라 분류할 때 첫 자리의 숫자가 커질수록 그 분포가 점차 감소되는 현상을 말한다. 이러한 벤포드 법칙은 일반식으로 도출하여 다양한 자릿수로 확장하여 적용할 수 있는 연구결과가 제시되었으며, 회계학, 사회과학, 물리학, 컴퓨터과학, 생물학 등 다방면의 수치 자료에서 그 유효성이 확인되고 있다. 자릿수의 관찰빈도를 분석하는 것만으로 많은 양의 실생활 데이터에서 빠르고 쉽게 데이터 조작여부를 탐지하거나 1차적인 데이터 품질검사에 효과적으로 활용되고 있다. 본 연구에서는 다학제적 연구의 측면에서 수학·물리적 법칙인 벤포드 법칙을 일유량 등 다양한 수문학 측정자료에 적용하여 그 적용가능성을 확인하고 자료의 불균질성과 신뢰성을 빠르게 탐지할 수 있는 방법론을 제시하고자 한다. 수문자료는 공인심의를 통해 자료의 신뢰도를 확보하고 있으나 확정·배포까지 약 2년이 소요되어 활용기간 단축에 대한 사용자 요구가 지속되고 있는 실정이다. 따라서 본 연구에서는 분석대상 데이터의 자릿수 관찰빈도가 벤포드 법칙에 의한 예상자릿수 빈도를 따르는지 여부에 대한 가설을 설정하고 카이제곱 검정 또는 Kolmogorov-Smirnov(K-S) 검정 등을 통해 적합도에 대한 통계적 유의미함을 분석함으로써 대략적으로나마 빠르고 쉽게 측정자료의 신뢰성을 판단할 수 있다. 본 연구는 다양한 학문과의 결합을 통한 새로운 접근을 시도함으로써 빅데이터 시대에 효과적으로 수자원의 개발, 관리 및 운영의 의사결정을 하는데 도움이 될 수 있을 것으로 판단된다.

• The Korean Journal of Applied Statistics
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• v.29 no.1
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• pp.61-73
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• 2016

We consider the wild bootstrap Ljung-Box (LB) test for autocorrelation in residuals of fitted multivariate time series models. The asymptotic chi-square distribution under the IID assumption is traditionally used for the LB test; however, size distortion tends to occur in the usage of the LB test, due to the conditional heteroskedasticity of financial time series. In order to overcome such defects, we propose the wild bootstrap LB test for autocorrelation in residuals of fitted vector autoregressive and error correction models. The simulation study and real data analysis are conducted for finite sample performance.

• Journal of Korean Society of Transportation
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• v.18 no.5
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• pp.33-42
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• 2000

This Paper is a Part of research Project series to analyze unique traffic characteristics observable within weaving sections on urban freeways. The research objectives were to establish with headway distribution and maximum Passing volume on weaving sections the basis of weaving designs that can promote safety and efficiency. Until now, when one wants to check the maximum Passing volume on weaving sections, it is taken for granted using headway distribution of freeway basic section. However. it was suspected in this research that for weaving sections different form of headway distribution had better be used. To prove this, field surveys were made to count headway intervals which supposedly were influenced not only by freeway basic section flows but also by weaving flows and later on used to develop headway distribution for weaving sections. For validation of the developed headway distribution, $x^2$-test was applied to three different data set of observed headways, currently used headway distribution for basic sections(Pearson Type III distribution) and new headway distribution. The result indicated new headway distribution as the most appropriate distribution form. Also, maximum passing volume within weaving sections was calculated based on new headway distribution and compared with Drew's maximum Passing volume.

• Journal of the Korean Data and Information Science Society
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• v.20 no.1
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• pp.1-9
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• 2009

Let us consider that the variance function in regression model has a discontinuity/change point at unknown location. Yu and Jones (2004) proposed the local polynomial fit to estimate the log-variance function which break the positivity of the variance. Using the local polynomial fit, Huh (2008) estimate the discontinuity point of the log-variance function. We propose a test for the existence of a discontinuity point in the log-variance function with the estimated jump size in Huh (2008). The proposed method is based on the asymptotic distribution of the estimated jump size. Numerical works demonstrate the performance of the method.

• Journal of Korean Society of Transportation
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• v.24 no.6 s.92
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• pp.33-43
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• 2006

This research is to the selection of optimal probability distribution as well as the estimation for design hourly factor in consideration of traffic characteristic, such as road function, lane number and AADT. To accomplish the objectives, we are applied to various probability distribution using traffic data that observed at permanent traffic count points in 2005. The parameters or the selected 14 probability distribution were estimated based on the method of maximum likelihood and the validity condition of the estimated parameter The goodness-of-fit test, such as chi-square test. was performed as well as the estimation of design hourly factor. As a result, An appropriate distributions of each case were selected : Pearson V for two lane of rural roads, LogLogistic for the four lane of rural roads, LogLogistic for the urban roads, Extreme value for recreation roads. And optimal K factor are as following : $0.1{\sim}0.2 $ for two lane of rural roads, $0.09{\sim}0.14$ for the four lane of rural roads. $0.07{\sim}0.13$ for the urban roads, $0.1{\sim}0.2$ for recreation roads.

• Journal of the Korean Data and Information Science Society
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• v.27 no.2
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• pp.373-380
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• 2016

Even though Likert type data is ordinal scale, many researchers who regard Likert type data as interval scale adapt as parametric methods. In this research, simulations have been used to find out a proper analysis of Likert type data. The locations and response distributions of five point Likert type data samples having diverse distribution have been evaluated. In estimating samples' locations, we considered parametric method and non-parametric method, which are t-test and Mann-Whitney test respectively. In addition, to test response distribution, we employed Chi-squared test and Kolmogorov-Smirnov test. In this study, we assessed the performance of the four aforementioned methods by comparing Type I error ratio and statistical power.