• Title/Summary/Keyword: gamma prior

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Bayesian Estimation of Shape Parameter of Pareto Income Distribution Using LINEX Loss Function

  • Saxena, Sharad;Singh, Housila P.
    • Communications for Statistical Applications and Methods
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    • v.14 no.1
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    • pp.33-55
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    • 2007
  • The economic world is full of patterns, many of which exert a profound influence over society and business. One of the most contentious is the distribution of wealth. Way back in 1897, an Italian engineer-turned-economist named Vilfredo Pareto discovered a pattern in the distribution of wealth that appears to be every bit as universal as the laws of thermodynamics or chemistry. The present paper proposes some Bayes estimators of shape parameter of Pareto income distribution in censored sampling. Asymmetric LINEX loss function has been considered to study the effects of overestimation and underestimation. For the prior distribution of the parameter involved a number of priors including one and two-parameter exponential, truncated Erlang and doubly truncated gamma have been contemplated to express the belief of the experimenter s/he has regarding the parameter. The estimators thus obtained have been compared theoretically and empirically with the corresponding estimators under squared error loss function, some of which were reported by Bhattacharya et al. (1999).

Short note: on the use of radioelement ratios to enhance gamma-ray spectrometric data (단보: 감마선 스펙트로미터 자료의 짙을 향상시키기 위한 방사성원소 비의 사용에 대하여)

  • Minty, Brian
    • Geophysics and Geophysical Exploration
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    • v.14 no.1
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    • pp.116-120
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    • 2011
  • Radioelement ratios are useful for mapping subtle variations in radiometric signatures in map data. But the conventional method for calculating radioelement ratios has the significant limitation that if just one of the radioelements comprising the ratio has a small spread of concentration estimates relative to its mean, then it will not contribute significantly to the ratio map. However, if both the numerator and denominator are first normalised to approximately the same mean and spread prior to ratioing, then they will contribute equally to the enhancement of the differences between them across the map area.

Comparing the Bayesian Estimates of Hazard Rate of Mixed Distribution and Hazard Rates by the MLE Method

  • Suneung Ahn;Kim, Hyunmook
    • Proceedings of the Korean Operations and Management Science Society Conference
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    • 2003.11a
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    • pp.263-266
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    • 2003
  • This paper is intended to compare between the Bayesian estimates of hazard rate and the hazard rates of mixed distributions. In estimating hazard rates, especially when the MLE method is used, such difficulties as a lack of data and the existence of censored data make it difficult to estimate the rates. For this reason, the estimates of hazard rate based on the Bayesian approach are introduced. For the simplicity, the exponential and gamma distributions are adopted as a sampling distribution and its natural conjugate prior distribution, respectively.

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Estimating the Failure Rate of a Large Scaled Software in Multiple Input Domain Testing (다중입력영역시험에서의 대형 소프트웨어 고장률 추정 연구)

  • 문숙경
    • Journal of Korean Society for Quality Management
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    • v.30 no.3
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    • pp.186-194
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    • 2002
  • In this paper we introduce formulae for estimating the failure rate of a large scaled software by using the Bayesian rule when a black-box random testing which selects an element(test case) at random with equally likely probability, is performed. A program or software can be treated as a mathematical function with a well-defined (input)domain and range. For a large scaled software, their input domains can be partitioned into multiple subdomains and exhaustive testing is not generally practical. Testing is proceeding with selecting a subdomain, and then picking a test case from within the selected subdomain. Whether or not the proportion of selecting one of the subdomains is assumed probability, we developed the formulae either case by using Bayesian rule with gamma distribution as a prior distribution.

Statistical Methods for Tomographic Image Reconstruction in Nuclear Medicine (핵의학 단층영상 재구성을 위한 통계학적 방법)

  • Lee, Soo-Jin
    • Nuclear Medicine and Molecular Imaging
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    • v.42 no.2
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    • pp.118-126
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    • 2008
  • Statistical image reconstruction methods have played an important role in emission computed tomography (ECT) since they accurately model the statistical noise associated with gamma-ray projection data. Although the use of statistical methods in clinical practice in early days was of a difficult problem due to high per-iteration costs and large numbers of iterations, with the development of fast algorithms and dramatically improved speed of computers, it is now inevitably becoming more practical. Some statistical methods are indeed commonly available from nuclear medicine equipment suppliers. In this paper, we first describe a mathematical background for statistical reconstruction methods, which includes assumptions underlying the Poisson statistical model, maximum likelihood and maximum a posteriori approaches, and prior models in the context of a Bayesian framework. We then review a recent progress in developing fast iterative algorithms.

Amentoflavone Acts as a Radioprotector for Irradiated v79 Cells by Regulating Reactive Oxygen Species (ROS), Cell Cycle and Mitochondrial Mass

  • Xu, Ping;Jiang, En-Jin;Wen, Si-Yuan;Lu, Dan-Dan
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.18
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    • pp.7521-7526
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    • 2014
  • Radioprotective effects of amentoflavone were investigated by examining cell viability, apoptosis, cell cycling concentrations of intracellular ROS (reactive oxygen species), and relative mitochondrial mass by flow cytometry after $^{60}Co$ irradiation. Pretreatment with amentoflavone 24 hours prior to 8 Gy $^{60}Co$ ${\gamma}$-ray irradiation significantly inhibited apoptosis, promoted the G2 phase, decreased the concentration of ROS and mitochondrial mass. These results collectively indicate that amentoflavone is an effective radioprotective agent.

Bayesian Multiple Change-Point Estimation for Single Quantum Dot Luminescence Intensity Data (단일 양자점으로부터 발생한 발광세기 변화에 대한 베이지안 다중 변화점 추정)

  • Kima, Jaehee;Kimb, Hahkjoon
    • The Korean Journal of Applied Statistics
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    • v.26 no.4
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    • pp.569-579
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    • 2013
  • In the field of single-molecule spectroscopy, it is essential to analyze luminescence Intensity changes that result from a single molecule. With the CdSe/ZnS core-shell structured quantum dot photon emission data Bayesian multiple change-point estimation is done with the gamma prior for Poisson parameters and truncated Poisson distribution for the number of change-points.

Studies on Biodegradation of Synthetic Detergents by Radiation (합성세제(合成洗劑)가 방사선(放射線)에 의한 생분해(性分解)에 관(關)한 연구(硏究))

  • Chun, Sae-Yoel;Lee, Sook-Kyung
    • Journal of the Korean Applied Science and Technology
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    • v.3 no.1
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    • pp.73-77
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    • 1986
  • The effect of $^{60}Co$ are discussed with regard to radiochemical destruction detergent. The study deals specifically with the effect gamma radiation from $^{60}Co$ source upon aquous solution of detergent. Test on biodegradation of A B S (solium alkyl benzene sulfonate) under the waste-water prior to the detergent conversion to biodegradable surfactants. The reason for removal of A B S was their extreme environmental stability and the associateo appearance of foam in waste water treatment plants. Although the A B S are considered biodegradable the time required for biodegradation in practical with the present environmental guidelines.

Changes of Lamellar Structure of TiAl Intermetallic Compound Heat Treatment (열처리에 따른 TiAl금속간화합물의 층상조직 변화)

  • Shin, Jae-Kwan;Chung, In-Sang;Park, Kyuong-Chae
    • Journal of the Korean Society for Heat Treatment
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    • v.6 no.3
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    • pp.127-137
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    • 1993
  • The changes of lamellar(${\alpha}_2+{\gamma}$) structure of TiAl intermetallic compound which is a high potential, high temperature aerospace material was investigated by heat treatment. The lamellar structure was short and made subgrain in prior a grains after homogenizing at 1523 K. It became longer and finer, and the subgrain went out during subsequent isothermal heatteating at 1273 K. The yield, fracture strength and strain to fracture if the heat treated specimens was increased and the hardness of them was decreased a little in the finer lamellar structure, because fine lamellar interface, sugrain boundary and grain boundary may block initiation and propagation of crack.

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A new extension of Lindley distribution: modified validation test, characterizations and different methods of estimation

  • Ibrahim, Mohamed;Yadav, Abhimanyu Singh;Yousof, Haitham M.;Goual, Hafida;Hamedani, G.G.
    • Communications for Statistical Applications and Methods
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    • v.26 no.5
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    • pp.473-495
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    • 2019
  • In this paper, a new extension of Lindley distribution has been introduced. Certain characterizations based on truncated moments, hazard and reverse hazard function, conditional expectation of the proposed distribution are presented. Besides, these characterizations, other statistical/mathematical properties of the proposed model are also discussed. The estimation of the parameters is performed through different classical methods of estimation. Bayes estimation is computed under gamma informative prior under the squared error loss function. The performances of all estimation methods are studied via Monte Carlo simulations in mean square error sense. The potential of the proposed model is analyzed through two data sets. A modified goodness-of-fit test using the Nikulin-Rao-Robson statistic test is investigated via two examples and is observed that the new extension might be used as an alternative lifetime model.