• Title/Summary/Keyword: Shape prior

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Bayesian Estimation of the Two-Parameter Kappa Distribution

  • Oh, Mi-Ra;Kim, Sun-Worl;Park, Jeong-Soo;Son, Young-Sook
    • Communications for Statistical Applications and Methods
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    • v.14 no.2
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    • pp.355-363
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    • 2007
  • In this paper a Bayesian estimation of the two-parameter kappa distribution was discussed under the noninformative prior. The Bayesian estimators are obtained by the Gibbs sampling. The generation of the shape parameter and scale parameter in the Gibbs sampler is implemented using the adaptive rejection Metropolis sampling algorithm of Gilks et al. (1995). A Monte Carlo study showed that the Bayesian estimators proposed outperform other estimators in the sense of mean squared error.

Bayesian estimation in the generalized half logistic distribution under progressively type-II censoring

  • Kim, Yong-Ku;Kang, Suk-Bok;Se, Jung-In
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.5
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    • pp.977-989
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    • 2011
  • The half logistic distribution has been used intensively in reliability and survival analysis especially when the data is censored. In this paper, we provide Bayesian estimation of the shape parameter and reliability function in the generalized half logistic distribution based on progressively Type-II censored data under various loss functions. We here consider conjugate prior and noninformative prior and corresponding posterior distributions are obtained. As an illustration, we examine the validity of our estimation using real data and simulated data.

Bayesian estimations on the exponentiated half triangle distribution under Type-I hybrid censoring

  • Kim, Yong-Ku;Kang, Suk-Bok;Seo, Jung-In
    • Journal of the Korean Data and Information Science Society
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    • v.22 no.3
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    • pp.565-574
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    • 2011
  • The exponenetiated distribution has been used in reliability and survival analysis especially when the data is censored. In this paper, we derive Bayesian estimation of shape parameter and reliability function in the exponenetiated half triangle distribution based on Type-I hybrid censored data. Here we consider conjugate prior and noninformative prior and obtained corresponding posterior distributions. As an illustration, the mean square errors of the estimates are computed. Comparisons are made between these estimators using Monte Carlo simulation study.

Default Bayesian testing equality of scale parameters in several inverse Gaussian distributions

  • Kang, Sang Gil;Kim, Dal Ho;Lee, Woo Dong
    • Journal of the Korean Data and Information Science Society
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    • v.26 no.3
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    • pp.739-748
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    • 2015
  • This paper deals with the problem of testing about the equality of the scale parameters in several inverse Gaussian distributions. We propose default Bayesian testing procedures for the equality of the shape parameters under the reference priors. The reference prior is usually improper which yields a calibration problem that makes the Bayes factor to be defined up to a multiplicative constant. Therefore we propose the default Bayesian testing procedures based on the fractional Bayes factor and the intrinsic Bayes factors under the reference priors. Simulation study and an example are provided.

Bayesian Estimations on the Exponentiated Distribution Family with Type-II Right Censoring

  • Kim, Yong-Ku;Kang, Suk-Bok;Seo, Jung-In
    • Communications for Statistical Applications and Methods
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    • v.18 no.5
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    • pp.603-613
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    • 2011
  • Exponentiated distribution has been used in reliability and survival analysis especially when the data is censored. In this paper, we derive Bayesian estimation of the shape parameter, reliability function and failure rate function in the exponentiated distribution family based on Type-II right censored data. We here consider conjugate prior and noninformative prior and corresponding posterior distributions are obtained. As an illustration, the mean square errors of the estimates are computed. Comparisons are made between these estimators using Monte Carlo simulation study.

Bayesian Method on Sequential Preventive Maintenance Problem

  • Kim Hee-Soo;Kwon Young-Sub;Park Dong-Ho
    • Communications for Statistical Applications and Methods
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    • v.13 no.1
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    • pp.191-204
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    • 2006
  • This paper develops a Bayesian method to derive the optimal sequential preventive maintenance(PM) policy by determining the PM schedules which minimize the mean cost rate. Such PM schedules are derived based on a general sequential imperfect PM model proposed by Lin, Zuo and Yam(2000) and may have unequal length of PM intervals. To apply the Bayesian approach in this problem, we assume that the failure times follow a Weibull distribution and consider some appropriate prior distributions for the scale and shape parameters of the Weibull model. The solution is proved to be finite and unique under some mild conditions. Numerical examples for the proposed optimal sequential PM policy are presented for illustrative purposes.

Determination of Reactivity by MO Theory (XX). An MO Theoretical Study on Mechanism of Thiocarbonyl Addition.

  • Lee, IK-Choon;Yang, Ki-Yull
    • Bulletin of the Korean Chemical Society
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    • v.2 no.4
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    • pp.132-138
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    • 1981
  • Ab initio molecular orbital calculations have been performed in an effort to determine which types of chemical interactions play essential roles for the system, , $H_2O+CH_2SH^+$, and $H_2O+ CH_2S$. The most important contribution to the interaction energy in controlling reaction path is the exchange repulsion energy, EX, which is largely responsible for the shape of the total interaction energy curve. In the ion-molecule reaction, prior protonation of thioformaldehyde or prior deprotonation of water leads to formation of the corresponding ionic adducts ($H_2O+CH_2SH$ and $HOCH_2S^-$), with no barrier to reaction, simulating specific acid and base catalysis, respectively, as in the case of formaldehyde. Otherwise, approach of water to thioformaldehyde gives rise to a completely repulsive interaction.

Effect of Grain Size and Predeformation on Shape Memory Ability and Transformation Temperature in Iron Base Fe-Mn-Si System Shape Memory Alloy (다결정질 Fe-Mn-Si계 형상기억합금의 형상기억합금과 변태점에 미치는 결정입도와 이전가공의 영향)

  • Choi, Chong Sool;Kim, Hyun Woo;Jin, Won;Shon, In Jin;Baek, Seung Han
    • Journal of the Korean Society for Heat Treatment
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    • v.3 no.1
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    • pp.34-41
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    • 1990
  • Effects of grain size and cold rolling degree on shape memory ability and transformation temperature were studied in Fe-35% Mn-6% Si shape memory alloy. Md point of the alloy was determined by variation of yield stress with test temperature. The Md point measured in this way was linearly increased with increasing grain size. Shape memory ability of the alloy was decreased with increasing grain size, showing a minimum value at around $63{\mu}m$, and then increased with increasing grain size. From this result, it was concluded that the shape memory ability in the grain size smaller than a critical value is controlled by amount of retained ${\gamma}$ and prior ${\varepsilon}$ phase, but that the shape memory ability in the grain size greater than the critical value is mainly dominated by grain boundary area in unit volume of parent phase. The shape memory ability was decreased with increasing deformation degree. This was because the ${\gamma}$ content being available for the formation of ${\varepsilon}$ martensite during bending was decreased with increasing deformation degree.

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The Comparative Study based on Gompertz Software Reliability Model of Shape Parameter (곰페르츠형 형상모수에 근거한 소프트웨어 신뢰성모형에 대한 비교연구)

  • Shin, Hyun Cheul;Kim, Hee Cheul
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.10 no.2
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    • pp.29-36
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    • 2014
  • Finite failure NHPP software reliability models presented in the literature exhibit either constant, monotonic increasing or monotonic decreasing failure occurrence rates per fault. In this paper, proposes the Gompertz distribution reliability model, which made out efficiency application for software reliability. Algorithm to estimate the parameters used to maximum likelihood estimator and bisection method, model selection based on mean square error (MSE) and coefficient of determination$(R^2)$, for the sake of efficient model, was employed. Analysis of failure using real data set for the sake of proposing fixed shape parameter of the Gompertz distribution was employed. This analysis of failure data compared with the Gompertz distribution model of shape parameter. In order to insurance for the reliability of data, Laplace trend test was employed. In this study, the proposed Gompertz model is more efficient in terms of reliability in this area. Thus, Gompertz model can also be used as an alternative model. From this paper, software developers have to consider the growth model by prior knowledge of the software to identify failure modes which can was helped.

Joint Segmentation of Multi-View Images by Region Correspondence (영역 대응을 이용한 다시점 영상 집합의 통합 영역화)

  • Lee, Soo-Chahn;Kwon, Dong-Jin;Yun, Il-Dong;Lee, Sang-Uk
    • Journal of Broadcast Engineering
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    • v.13 no.5
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    • pp.685-695
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    • 2008
  • This paper presents a method to segment the object of interest from a set of multi-view images with minimal user interaction. Specifically, after the user segments an initial image, we first estimate the transformations between foreground and background of the segmented image and the neighboring image, respectively. From these transformations, we obtain regions in the neighboring image that respectively correspond to the foreground and the background of the segmented image. We are then able to segment the neighboring image based on these regions, and iterate this process to segment the whole image set. Transformation of foregrounds are estimated by feature-based registration with free-form deformation, while transformation of backgrounds are estimated by homography constrained to affine transformation. Here, both are based on correspondence point pairs. Segmentation is done by estimating pixel color distributions and defining a shape prior based on the obtained foreground and background regions and applying them to a Markov random field (MRF) energy minimization framework for image segmentation. Experimental results demonstrate the effectiveness of the proposed method.