• Communications for Statistical Applications and Methods
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• v.15 no.3
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• pp.403-409
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• 2008

In this paper we show that the peak of the type I error rate of the Oochran-Armitage trend test could be greater than the nominal level when $2\;{\times}\;C$ contingency tables obtained from two multinomial distributions are extremely unbalanced. This result justifies the use of the exact Cochran-Armitage trend test in extremely unbalanced $2\;{\times}\;C$ contingency tables.

• Journal of Life Science
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• v.12 no.6
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• pp.676-681
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• 2002

Gibbons are called lesser apes and classified hominoidae, catarrhini, anthropoidea, primates. They are successfully speciated with 12 species, 4 generas, in tropical forest of Southeast Asia. Ten species among them are endangered. Compared to other primates, gibbons are highly endangered. However, we do not know exact geographical distributions of gibbons and their subspecies numbers. Therefore further investigations are needed for lesser apes. It is of great important to know exact phylogenetic relationships with the information of distribution and identification of gibbon species in order to understand speciation and conservation of gibbons.

• Communications for Statistical Applications and Methods
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• v.24 no.3
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• pp.271-290
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• 2017

We study a bivariate response regression model with arbitrary marginal distributions and joint distributions using Frank and Clayton's families of copulas. The proposed model is used for fitting dependent bivariate data with explanatory variables using the log-odd log-logistic Weibull distribution. We consider likelihood inferential procedures based on constrained parameters. For different parameter settings and sample sizes, various simulation studies are performed and compared to the performance of the bivariate odd-log-logistic-Weibull regression model. Sensitivity analysis methods (such as local and total influence) are investigated under three perturbation schemes. The methodology is illustrated in a study to assess changes on schoolchildren's oral health-related quality of life (OHRQoL) in a follow-up exam after three years and to evaluate the impact of caries incidence on the OHRQoL of adolescents.

• Journal of the Korea Society of Computer and Information
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• v.3 no.2
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• pp.131-138
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• 1998

In usual statistical data analysis, we describe statistical data by exact values. However, in modem complex and large-scale systems, it is difficult to treat the systems using only exact data. In this paper, we define these data as fuzzy data(ie. Linguistic variable applied to make the member-ship function.) and Propose a new method to get an analysis of fuzzy survey data based on the maximum entropy Principle. Also, we propose a new method of discrimination by measuring distance between a distribution of the stable state and estimated distribution of the present state using the Kullback - Leibler information. Furthermore, we investigate the validity of our method by computer simulations under realistic situations.

• Proceeding of EDISON Challenge
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• 2015.03a
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• pp.285-291
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• 2015

In this paper, a composite material analysis program based on the finite element method(FEM) is used. The purpose of this study was to verify whether the composite material analysis program which developed as part of a project of development of softwares and educational contents for structural vibration and composite material analysis that can calculate how similar the macroscopic mechanical behavior of the composite materials actually. Because composite materials are generally anisotropic, analysis of composite laminate is used for the constitutive equations of orthotropic material. For convenience, the unit is ommited in all calculations. To verify the accuracy of the finite element method based program, the deflection and stress distribution of the simply supported composite material laminated plate subjected to a uniform load distribution is compared with exact solution. Size and properties of the composite material laminate used for analysis are fixed variables, and by changing the number of elements and the total thickness of the laminate is compared with the exact solution to the resulting value, respectively.

• Computational Structural Engineering
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• v.10 no.1
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• pp.159-171
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• 1997

This study investigates the stress distribution in a transversely isotropic medium containing a spheroidal cavity where the medium is under uniaxial tension in z-direction in one case and pure shear in the plane of isotropy in another case. The technical approach used in this study combines exact analytical and numerical methods. The exact analytical method is based upon three potential functions taken in terms of the Legendre associated functions of the first and second kind. The numerical method is based upon the finite difference approach. Numerical results concerning the two loading conditions with five anisotropic materials are presented.

• Communications for Statistical Applications and Methods
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• v.1 no.1
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• pp.75-80
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• 1994

Parametric estimators of two parameter exponential distribution in the presence of unidentified outliers are proposed, and the means and variances of the estimators are obtained as the exact forms.

• Journal of Korean Society for Quality Management
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• v.14 no.1
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• pp.39-46
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• 1986

This paper considers two sided tests for exponential null distribution against NBUE or NWUE alternative in life testing. The main results concern the strong consistency of two proposed statistics, one being similar to Kolmogorov - Smirnov statistic, the other similar to Cramer-Von Mises statistic. Also obtained are the asymtotic null distribution and the exact Bahadur slope of the statistic similar to Kolmogorov-Smirnov.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.24-30
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• 1993

When modeling a complex system we use an event tree to analyze propagation of failure. An event tree cannot represent the statistical interrelationships among parameters, but it can be represented as a statistically identical influence diagram so that parameter updating can be easily performed. After updating parameters we can calculate posterior distribution of the failure rate for each path. But exact distribution requires considerably complex numerical integration. We propose an approximation method to calculate the posterior and derive the predictive distribution of the time to next failure. Finally we introduce the system which implements our methodology.

• The Korean Journal of Applied Statistics
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• v.22 no.5
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• pp.1097-1102
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• 2009

Classification of subjects with unknown distribution in small sample size setup may involve order-restricted constraints in multivariate parameter setups. Those problems makes optimality of conventional likelihood ratio based statistical inferences not feasible. Fortunately, Roy (1953) introduced union-intersection principle(UIP) which provides an alternative avenue. Redescending M-estimator along with that principle yields a considerably appropriate robust testing procedure. Furthermore, conditionally distribution-free test based upon exact permutation theory is used to generate p-values, even in small sample. Applications of this method are illustrated in simulated data and read data example (Lobenhofer et al., 2002)