• Journal of the Korean Data and Information Science Society
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• 제25권4호
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• pp.903-914
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• 2014

The inverse Weibull distribution has been proposed as a model in the analysis of life testing data. Also, inverse Weibull distribution has been recently derived as a suitable model to describe degradation phenomena of mechanical components such as the dynamic components (pistons, crankshaft, etc.) of diesel engines. In this paper, we derive the approximate maximum likelihood estimators of the scale parameter and the shape parameter in the inverse Weibull distribution under multiply type-II censoring. We also develop four modified empirical distribution function (EDF) type tests for the inverse Weibull or extreme value distribution based on multiply type-II censored samples. We also propose modified normalized sample Lorenz curve plot and new test statistic.

• 한국전자통신학회논문지
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• 제18권5호
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• pp.935-944
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• 2023

본 연구에서는 신뢰성 연구에 적합하다고 알려진 Inverse-type(: Inverse-Exponential, Inverse-Rayleigh) 수명분포를 유한고장 NHPP(: Nonhomogeneous Poisson Process) 기반의 소프트웨어 개발비용 모형에 적용한 후, 성능을 결정하는 속성을 분석하였다. 또한, 모형의 효율성을 평가하기 위해 Goel-Okumoto 기본 모형과 함께 비교하였다. 고장 시간 데이터를 이용하여 모형의 성능을 분석하였고, 모수의 계산은 MLE(: Maximum Likelihood Estimation)를 적용하였다. 결론적으로, 첫째, 개발비용을 결정하는 m(t)를 분석한 결과, Inverse-Exponential 모형이 참값에 대한 오차가 적어 효율적이었다. 둘째, 개발비용과 함께 방출시간을 분석한 결과 Inverse-Rayleigh 모형이 가장 좋은 것으로 확인되었다. 셋째, 제안된 모형의 속성(m(t), 비용, 방출시간)을 종합적으로 평가한 결과, Inverse-Rayleigh 모형의 성능이 가장 우수하였다. 따라서 소프트웨어 개발자가 초기 프로세스에서 본 연구 데이터를 효율적으로 활용할 수 있다면, 비용에 영향을 미치는 속성들을 사전에 탐색하고 분석할 수 있을 것이다.

• Communications for Statistical Applications and Methods
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• 제28권2호
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• pp.99-118
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• 2021

In this paper, we introduce an extended form of the inverse power Lomax model via Marshall-Olkin approach. We call it the Marshall-Olkin inverse power Lomax (MOIPL) distribution. The four- parameter MOIPL distribution is very flexible which contains some former and new models. Vital properties of the MOIPL distribution are affirmed. Maximum likelihood estimators and approximate confidence intervals are considered under Type I censored samples. Maximum likelihood estimates are evaluated according to simulation study. Bayesian estimators as well as Bayesian credible intervals under symmetric loss function are obtained via Markov chain Monte Carlo (MCMC) approach. Finally, the flexibility of the new model is analyzed by means of two real data sets. It is found that the MOIPL model provides closer fits than some other models based on the selected criteria.

• Communications for Statistical Applications and Methods
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• 제27권4호
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• pp.469-486
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• 2020

Entropy is an important term in statistical mechanics that was originally defined in the second law of thermodynamics. In this paper, we consider the maximum likelihood estimation (MLE), maximum product spacings estimation (MPSE) and Bayesian estimation of the entropy of an inverse Weibull distribution (InW) under a generalized type I progressive hybrid censoring scheme (GePH). The MLE and MPSE of the entropy cannot be obtained in closed form; therefore, we propose using the Newton-Raphson algorithm to solve it. Further, the Bayesian estimators for the entropy of InW based on squared error loss function (SqL), precautionary loss function (PrL), general entropy loss function (GeL) and linex loss function (LiL) are derived. In addition, we derive the Lindley's approximate method (LiA) of the Bayesian estimates. Monte Carlo simulations are conducted to compare the results among MLE, MPSE, and Bayesian estimators. A real data set based on the GePH is also analyzed for illustrative purposes.

• 패션비즈니스
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• 제14권1호
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• pp.11-26
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• 2010

This study was carried out using personal measurement for female college students who have a great interest in fashion at 20-24 age, and examined somatotype character. As a means of a character type test, the grades were laid by using MBTI which proved to be objective, and relativity between character types was laid by conducting correlation analysis. The conclusions which can be drawn from this study are as followed. 1. In 4 preference index, which was classified by MBTI, Sensing(S) type was the highest of 17.27% at the average and 68.5% at the distribution rate each. The average of Extraversion(E) type was 14.56% and it's distribution rate was 64.5%. Index of types were : Intuition(N) 12.49%, Introversion(I) 11.75%, Perceiving(P) 12.50%. Average distribution rate of each types were : N 31.5%, I 35.5%, P 40.3%. And average of Sensing(S) type was the lowest, 11.09%. Like American Students, the subjects of this study showed higher in the E type than in the I type. The distribution rate of 16 character types of MBTI were : ESTJ 18.5%, ESFP 13.7%, ISTJ and ESFJ 9.7%. But INTP and INFP were low, 2.4% and 0.8%. 2. Average sizes of subjects for this study were : height 160.49cm, weight 51.83kg, bust 83.22cm, waist 65.49cm, hips 90.70cm. As compared with measurement of women at 20-24 age of Size Korea(2004), the subjects of this study showed less, about 0.2-5cm in height, 0.2-2cm in circumference except in waist, and 0.5-3.6cm in length. 3. After examining the relativity between personal measurement categories of the subjects and character type through the MBTI, Extraversion(E) type showed inverse correlation in stature, height, biacromial breadth, and subcutaneous fat thickness of posterior iliospinale. Contrary to the E type, the Introversion(I) type showed positive correlation. Sensing(S) type showed inverse correlation only in biacromial breadth, Intuition(N) type showed positive correlation in most categories including height, width and the subcutaneous fat thickness. Thinking(T) type showed positive correlation in bust point-bust point, chest depth and hip width. Feeling(F) type, on the other hand, showed inverse correlation. The Judging(J) type showed inverse correlation in stature, height, length and the parts of chest. In contrast, Perceiving(P) type showed positive correlation in other categories including biacromial breadth, same as the J type.

• Advances in aircraft and spacecraft science
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• 제5권6호
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• pp.671-689
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• 2018

Bending, buckling and free vibration responses of functionally graded (FG) higher-order beams resting on two parameter (Winkler-Pasternak) elastic foundation are studied using a new inverse hyperbolic beam theory. The material properties of the beam are graded along the thickness direction according to the power-law distribution. In the present theory, the axial displacement accounts for an inverse hyperbolic distribution, and the transverse shear stress satisfies the traction-free boundary conditions on the top and bottom surfaces of the beams. Hamilton's principle is employed to derive the governing equations of motion. Navier type analytical solutions are obtained for the bending, bucking and vibration problems. Numerical results are obtained to investigate the effects of power-law index, length-to-thickness ratio and foundation parameter on the displacements, stresses, critical buckling loads and frequencies. Numerical results by using parabolic beam theory of Reddy and first-order beam theory of Timoshenko are specially generated for comparison of present results and found in excellent agreement with each other.

• 산업경영시스템학회지
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• 제11권17호
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• pp.67-80
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• 1988

This study is concerned with the comparison of two time homogeneous Poisson processes. Traditionally, the methods of testing equality of Poisson processes were based on the binomial distribution or its normal approximations. The sampling plans used in these methods are to observe the processes concurrently over a predetermined time interval, possibly different for each process. However, when the values of the intensities of the processes are small, inverse type sampling plans are more appropriate since there may be cases where only a few or even no events are observed in the predetermined time interval. This study considers 9 inverse type sampling plans for the comparison of two Poisson processes. For each sampling plans considered, critical regions and the design parameters of the sampling plan are determined to guarantee the significance level and the power at some values of the alternative hypothesis. The Problem of comparing of two Weibull processes are also considered.

• Communications for Statistical Applications and Methods
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• 제31권1호
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• pp.65-85
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• 2024

The tail probability of a function of a multivariate random variable is not easy to estimate by the crude Monte Carlo simulation. When the occurrence of the function value over a threshold is rare, the accurate estimation of the corresponding probability requires a huge number of samples. When the explicit form of the cumulative distribution function of each component of the variable is known, the inverse transform likelihood ratio method is directly applicable scheme to estimate the tail probability efficiently. The method is a type of the importance sampling and its efficiency depends on the selection of the importance sampling distribution. When the cumulative distribution of the multivariate random variable is represented by a copula and its marginal distributions, we develop an iterative algorithm to find the optimal importance sampling distribution, and show the convergence of the algorithm. The performance of the proposed scheme is compared with the crude Monte Carlo simulation numerically.

• 소성∙가공
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• 제9권3호
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• pp.304-312
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• 2000

An inverse finite element approach is employed to efficiently design the optimum blank shape and intermediate shapes from the desired final shape in multi-stage elliptic cup drawing processes. The multi-stage deep-drawing process is difficult to design with the conventional finite element analysis since the process is very complicate with the conventional finite element analysis since the process is very complicated with intermediate shapes and the numerical analysis undergoes the convergence problem even with tremendous computing time. The elliptic cup drawing process needs much effort to design sine it requires full three-dimensional analysis. The inverse analysis is able to omit all complicated and tedious analysis procedures for the optimum process design. In this paper, the finite element inverse analysis provides the thickness strain distribution of each intermediate shape through the multi-stage analysis. The multi-stage analysis deals with the convergence among intermediate shapes and the corresponding sliding constraint surfaces that are described by the analytic function of merged-arc type surfaces.

• 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.