• Communications for Statistical Applications and Methods
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• 제19권6호
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• pp.899-904
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• 2012

High-dimensional categorical data models with small sample sizes have not been used extensively in genomic sequences that involve count (or discrete) or purely qualitative responses. A basic task is to identify differentially expressed genes (or positions) among a number of genes. It requires an appropriate test statistics and a corresponding multiple testing procedure so that a multivariate analysis of variance should not be feasible. A family wise error rate(FWER) is not appropriate to test thousands of genes simultaneously in a multiple testing procedure. False discovery rate(FDR) is better than FWER in multiple testing problems. The data from the 2002-2003 SARS epidemic shows that a conventional FDR procedure and a proposed test statistic based on a pseudo-marginal approach with Hamming distance performs better.

• Journal of the Korean Data and Information Science Society
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• 제18권3호
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• pp.833-845
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• 2007

When X and Y have independent exponential distributions, we develop a Bayesian testing procedure for the ratio of two quantiles under reference prior. The noninformative prior such as reference prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. So we develop a Bayesian testing procedure based on fractional Bayes factor and intrinsic Bayes factor. We show that the posterior density under the reference prior is proper and propose the Bayesian testing procedure for the ratio of two quantiles using fractional Bayes factor and intrinsic Bayes factor. Simulation study and a real data example are provided.

• 품질경영학회지
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• 제24권3호
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• pp.50-64
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• 1996

This article is concerned with procedures for detecting multiple y outliers in linear regression. The outward-testing procedure, which is controled by the initial subset and the minimum residuals, is suggested by two phases. The performance of this procedure is compared with others by Monte Carlo techniques and found to be superior. The procedure, however, fails in detecting y outliers that are on high-leverage cases in Phase 1. Thus, we proposed ELMS algorithm for a set of suspect observations, in Phase 1. In Phase 2, the proposed testing is conducted using the studentized residuals to see which of the suspect cases are outliers. Several examples are analyzed.

• Structural Engineering and Mechanics
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• 제26권5호
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• pp.499-516
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• 2007

An experimental method denoted as Impulse Method is proposed as a cost-effective non-destructive technique for the on-site evaluation of concrete elastic modulus in existing structures: on the basis of Hertz's quasi-static theory of elastic impact and with the aid of a simple portable testing equipment, it makes it possible to collect series of local measurements of the elastic modulus in an easy way and in a very short time. A Hypothesis Testing procedure is developed in order to provide a statistical tool for processing the data collected by means of the Impulse Method and assessing the possible occurrence of significant variations in the elastic modulus without exceeding some prescribed error probabilities. It is based on a particular formulation of the renowned sequential probability ratio test and reveals to be optimal with respect to the error probabilities and the required number of observations, thus further improving the time-effectiveness of the Impulse Method. The results of an experimental investigation on different types of plain concrete prove the validity of the Impulse Method in estimating the unknown value of the elastic modulus and attest the effectiveness of the proposed Hypothesis Testing procedure in identifying significant variations in the elastic modulus.

• Communications for Statistical Applications and Methods
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• 제15권4호
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• pp.531-542
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• 2008

시계열 자료를 분석할 때, 시계열 자료가 가지고 있는 추세를 제거하기 위하여 결정적 추세인 경우 회귀모형을 이용하고, 확률적 추세인 경우 차분하는 방법을 이용한다. 이 때 제거의 옳바른 기준이 되는 검정 방법이 단위근 검정이다. 그러나 기존의 Dickey-Fuller 검정 (Dickey와 Fuller, 1979)은 표본 수가 작고, 단위근에 가까울 경우 검정력이 낮으며, 베이지안 단위근 검정은 절차가 복잡하다. 본 논문에서는 기존의 두 방법들의 문제점을 해결하기 위하여, 전통적 Dickey-Fuller 검정 방법과 베이지안 방법을 결합한 형태의 검정방법으로 제안하였다. 제안된 검정방법은 모형 AR(1)에서 계수가 거의 1이거나 표본 수가 작을 경우, 기존의 Dickey-Fuller 검정보다 검정력이 높을 뿐만 아니라 일반적인 베이지안 방법 보다 절차가 간단한 검정법이 된다.

• 비파괴검사학회지
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• 제11권1호
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• pp.44-51
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• 1991

This paper describes the practical difficulties experienced with ultrasonic testing during site fabrication of the offshore structures, and indicates some of the problems when UT indications are evaluated according to written procedure which is prepared to the requirements of the applicable code (standard) and/or specification.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.337-346
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• 2001

In this paper we consider the problem of identifying and testing the outliers in linear regression. first we consider the problem for testing the null hypothesis of no outliers. The test based on the ratio of two scale estimates is proposed. We show the asymptotic distribution of the test statistic by Monte Carlo simulation and investigate its properties. Next we consider the problem of identifying the outliers. A forward sequential procedure based on the suggested test is proposed and shown to perform fairly well. The forward sequential procedure is unaffected by masking and swamping effects because the test statistic is based on robust estimate.

• Journal of applied mathematics & informatics
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• 제37권1_2호
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• pp.105-121
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• 2019

One of the main objective of manufacturing industries is to assess the capability performance of different processes. In this paper, we use the lifetime performance index $C_L$ as a criterion to measure larger-the-better type quality characteristic for evaluating the product performance. The lifetimes of products are assumed to follow a general class of inverted exponentiated distributions. We use maximum likelihood estimator to estimate the lifetime performance index under the assumption that data are progressive type I interval censored. We also obtain asymptotic distribution of this estimator. Based on this estimator, a new hypothesis testing procedure is developed with respect to a given lower specification limit. Finally, two numerical examples are discussed in support of the proposed testing procedure.

• 한국신뢰성학회지:신뢰성응용연구
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• 제7권4호
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• pp.137-148
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• 2007

Rapid increase of embedded systems in electronic and mechanical control systems requires reliable and error-free embedded software. State-based testing methods like FSM are usually used to assure the reliability of embedded software. However, because of possibility of explosion of test cases, only partial test cases are considered in practical tests, which cannot guarantee that all the possible errors are investigated. This study proposes a test procedure based on failure mechanisms that may occur in embedded systems, which can not only assure that certain kinds of possible errors are detected but reduce the testing time. The proposed procedure is applied to vehicle air control system.

• International Journal of Reliability and Applications
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• 제10권1호
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• pp.59-62
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• 2009

We comment on a new testing procedure for testing exponentiality against different ageing classes. We show that the proposed test is inappropriate at least for two alternatives. We point out the subtle flaw in their argument.