• Journal of the Korean Data and Information Science Society
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• v.21 no.3
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• pp.569-574
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• 2010

We consider two components system which have Freund's bivariate exponential model. In this case, Bayesian multiple comparisons procedure for failure rates is sug-gested in K Freund's bivariate exponential populations. Here we assume that the com-ponents enter the study at random over time and the analysis is carried out at some prespeci ed time. We derive fractional Bayes factor for all comparisons under non- informative priors for the parameters and calculate the posterior probabilities for all hypotheses. And we select a hypotheses which has the highest posterior probability as best model. Finally, we give a numerical examples to illustrate our procedure.

• Journal of the Korean Data and Information Science Society
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• v.16 no.4
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• pp.1129-1140
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• 2005

A nonparametric Bayesian method for calculating posterior probabilities of the multiple comparison problem on the parameters of several Geometric populations is presented. Bayesian multiple comparisons under two different prior/ likelihood combinations was studied by Gopalan and Berry(1998) using Dirichlet process priors. In this paper, we followed the same approach to calculate posterior probabilities for various hypotheses in a statistical experiment with a partition on the parameter space induced by equality and inequality relationships on the parameters of several geometric populations. This also leads to a simple method for obtaining pairwise comparisons of probability of successes. Gibbs sampling technique was used to evaluate the posterior probabilities of all possible hypotheses that are analytically intractable. A numerical example is given to illustrate the procedure.

• The Journal of Information Systems
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• v.8 no.2
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• pp.69-90
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• 1999

The purpose of this paper is to study the current status of Y2K settlement in korean business firms. To accomplish the purpose of this paper effectively, first of all, theoretical background of Y2K was reviewed briefly. Second, research hypotheses and methodology were discussed with the following topics: (1) research hypotheses (2) operational definitions of variables (3) survey population (4) data collection method (5) data analysis method. Third, current status and problems of Y2K problems were investigated in detail with the following areas: (1) characteristics of samples (2) comparisons of Y2K settlement by business area (3) comparisons of Y2K settlement by firm sizes (4) comparisons of Y2K settlement by degree of information systems (5) effective ways of settling Y2K problems Finally, this paper was summarized and future research directions were suggested briefly.

• Communications for Statistical Applications and Methods
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• v.19 no.2
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• pp.267-276
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• 2012

Bagai et al. (1989) proposed a distribution-free test for stochastic ordering in the competing risk model, and recently Murakami (2009) utilized a standard saddlepoint approximation to provide tail probabilities for the Bagai statistic under finite sample sizes. In the present paper, we consider the Gaussian-polynomial approximation proposed in Ha and Provost (2007) and compare it to the saddlepoint approximation in terms of approximating the percentiles of the Bagai statistic. We make numerical comparisons of these approximations for moderate sample sizes as was done in Murakami (2009). From the numerical results, it was observed that the Gaussianpolynomial approximation provides comparable or greater accuracy in the tail probabilities than the saddlepoint approximation. Unlike saddlepoint approximation, the Gaussian-polynomial approximation provides a simple explicit representation of the approximated density function. We also discuss the details of computations.

• Journal of Korean Society for Quality Management
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• v.33 no.1
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• pp.64-72
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• 2005

The ever increasing demand for enhanced competitiveness of engineered products requires "designing-in-quality" strategies that can effectively and efficiently incorporate concepts of uncertainty and quality into design. Multi-attribute utility function is commonly used to represent the decision-maker's preference on multiple design attributes under conditions of uncertainty and risk. One of the major issues in implementing this approach concerns the generation of appropriate utility function, especially in a complex engineering design environment. Typically, the decision maker's preference is revealed through lottery questions rather than being structured on the deductive reasoning to reflect the nonlinear tradeoffs among the attributes. The use of such intuitive procedures can lead to inexact preference information that may result in inaccuracy and rank reversal problems. This paper presents an alternative procedure based on the pair-wise comparisons between design alternatives towards a consistent preference presentation in assessing multiplicative utility function. The effectiveness of the overall procedures is tested with the aid of an injection-molding process design for a capacitor can and the results are discussed.

• Journal of applied mathematics & informatics
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• v.9 no.1
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• pp.239-252
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• 2002

A sort sequence $S_n$ is sequence of all unordered pairs of indices in $I_n$={1,2,…n}. With a sort sequence $S_n$ = ($s_1,S_2,...,S_{\frac{n}{2}}$),one can associate a predictive sorting algorithm A($S_n$). An execution of the a1gorithm performs pairwise comparisons of elements in the input set X in the order defined by the sort sequence $S_n$ except that the comparisons whose outcomes can be inferred from the results of the preceding comparisons are not performed. A sort sequence is said to be extremal if it maximizes a given objective function. First we consider the extremal sort sequences with respect to the objective function $\omega$($S_n$) - the expected number of tractive predictions in $S_n$. We study $\omega$-extremal sort sequences in terms of their prediction vectors. Then we consider the objective function $\Omega$($S_n$) - the minimum number of active predictions in $S_n$ over all input orderings.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.15 no.2
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• pp.81-87
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• 1990

International time comparisons using a commercial GPS receiver, with the common-view program of GPS satellite time links, have been carried out between Korea Standards Research Institute(KSRI) and Communications Research Laboratory(CRL) of Japan, and also between KSRI and United Stated Neval Observatory(USNO). The frequency stability is about 1.5 parts in $10^-13$ for the averaging time of 1day. The result of time comparisons obtained by the GPS common-view technique was about 10 times better than that by the LORAN-C(Long Range Navigation) ground wave technique.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.4
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• pp.435-441
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• 2012

This paper provides simulation-based results of effect analysis of sample size and sampling periods on accuracy of reliability estimation methods using multiple comparisons with analysis of variance. Sum of squared errors in estimated reliability measures were evaluated through applying seven estimation methods for one-shot systems to simulated quantal-response data. Analysis of variance was implemented to investigate change in these errors according to variations of sample size and sampling periods for each estimation method, and then the effect analysis on accuracy in reliability estimation was performed using multiple comparisons based on sample size and sampling periods. An efficient way to allocate both sample size and sampling periods for reliability estimation tests of one-shot systems is proposed in this paper from the effect analysis results.

• The Transactions of the Korean Institute of Power Electronics
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• v.26 no.3
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• pp.159-166
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• 2021

This study compares the maximum power point tracking (MPPT) control methods of a thermoelectric generator on vehicles. The researchers conduct comparisons on five different MPPT methods, including a fractional open circuit voltage method, a perturbation and observation (P&O) method, an incremental conductance method, a linear extrapolation-based MPPT (LEMPPT) method, and a LEMPPT/P&O hybrid method. These five MPPT methods are theoretically analyzed in detail, and the comparisons are conducted through MATLAB/Simulink simulation results. The comparison outcomes reveal that linear MPPT methods, including LEMPPT and LEMPPT/P&O hybrid methods, are more suitable for a thermoelectric generator on vehicles than the other MPPT methods examined in this work.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.5
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• pp.515-521
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• 2015

The SymMerge algorithm is an efficient merging algorithm for input sequences u and v of sizes $\left|u \right|=m$ and $\left|v \right|=n$, $m{\leq}n$. We consider complexity analysis for SymMerge algorithm regarding to the required number of comparisons. The focus of the previous complexity analysis was on finding the values of upper bounds, i.e. showing the asymptotical optimality. In this paper, in a different way from the previous complexity analysis, we show that the overall required number of comparisons for two representative special cases "symmetric case" and "maximum spanning case" can be calculated exactly i.e. the least upper bounds regarding to the required number of comparisons are calculated. Symmerge requires exactly $m\;log\frac{n}{m}+4m-logm-3$ comparisons for symmetric case of sizes $m=2^k,\;n=2^l,l{\geq}k$ of input sequences and exactly $\frac{1}{2}m^2+(m+1)logm-\frac{3}{2}m+2$ comparisons for maximum spanning case of sizes $m=2^k,n=2^m-m$ of input sequences. Additionally we show that the complexity of the Symmerge algorithm regarding to the overall required number of comparisons for these special cases can be defined by recurrence relations.