Objective:Acupuncture methods(including moxibustion)are used frequently in the treatment of herpes zoster.However,the choice is usually made only based on personal experience among different acupuncture methods.This s...Objective:Acupuncture methods(including moxibustion)are used frequently in the treatment of herpes zoster.However,the choice is usually made only based on personal experience among different acupuncture methods.This study compared the effectiveness of different acupuncture methods for herpes zoster.Methods:All randomized controlled trials(RCTs)of acupuncture methods for herpes zoster were searched in seven databases including Cochrane Library,Embase,PubMed,Web of Science,Wan-fang,CNKI,and CQVIP database.After screening process,effectiveness rate was extracted from all the included RCTs as primary outcomes.The Bayesian network meta-analysis was conducted by GeMTC 0.14.3,Stata13.0 and Review Man 5.3.Results:39 studies were included,which contained 3,042 participants among 11 interventions.Based on the results of network meta-analysis and ranking probability,fire-acupuncture plus electro-acupuncture is considered to be the most effective method,followed by body-acupuncture plus moxibustion,fire-acupuncture,surround-acupuncture plus moxibustion,moxibustion,surround-acupuncture plus western medicine,surround-acupuncture plus electro-acupuncture,body-acupuncture plus western medicine,surround-acupuncture,western medicine,body-acupuncture.Global and local inconsistency test suggested no significant difference between the results of direct and indirect comparisons.Conclusion:Acupuncture methods might be an effective alternative treatment for herpes zoster and fire-acupuncture plus electro-acupuncture might be considered the best option among the included treatments.However,the results of this study need to be interpreted with caution,because there may still be a problem of small sample size of some studies and interventions.Future research,with a standard methodology and design,requires large-scale trials to validate the effect identified in this meta-analysis.展开更多
Most studies of series system assume the causes of failure are independent,which may not hold in practice.In this paper,dependent causes of failure are considered by using a Marshall-Olkin bivariateWeibull distributio...Most studies of series system assume the causes of failure are independent,which may not hold in practice.In this paper,dependent causes of failure are considered by using a Marshall-Olkin bivariateWeibull distribution.We derived four reference priors based on several grouping orders.Gibbs sampling combined with the rejection sampling algorithm and Metropolis-Hastings algorithm is developed to obtain the estimates of the unknown parameters.The proposed approach is compared with the maximum-likelihood method via simulation.We find that the root-meansquared errors of the Bayesian estimates are much smaller for the case of small sample size,and that the coverage probabilities of the Bayesian estimates are much closer to the nominal levels.Finally,a real data-set is analysed for illustration.展开更多
The Wiener process as a degradation model plays an important role in the degradation analysis.In this paper, we propose an objective Bayesian analysis for an acceleration degradation Wienermodel which is subjected to ...The Wiener process as a degradation model plays an important role in the degradation analysis.In this paper, we propose an objective Bayesian analysis for an acceleration degradation Wienermodel which is subjected to measurement errors. The Jeffreys prior and reference priors underdifferent group orderings are first derived, the propriety of the posteriors is then validated. It isshown that two of the reference priors can yield proper posteriors while the others cannot. A simulation study is carried out to investigate the frequentist performance of the approach comparedto the maximum likelihood method. Finally, the approach is applied to analyse a real data.展开更多
In Bayesian quantile smoothing spline[Thompson,P.,Cai,Y.,Moyeed,R.,Reeve,D.,&Stander,J.(2010).Bayesian nonparametric quantile regression using splines.Computational Statistics and Data Analysis,54,1138-1150.],a fi...In Bayesian quantile smoothing spline[Thompson,P.,Cai,Y.,Moyeed,R.,Reeve,D.,&Stander,J.(2010).Bayesian nonparametric quantile regression using splines.Computational Statistics and Data Analysis,54,1138-1150.],a fixed-scale parameter in the asymmetric Laplace likelihood tends to result in misleading fitted curves.To solve this problem,we propose a new Bayesian quantile smoothing spline(NBQSS),which considers a random scale parameter.To begin with,we justify its objective prior options by establishing one sufficient and one necessary condition of the posterior propriety under two classes of general priors including the invariant prior for the scale component.We then develop partially collapsed Gibbs sampling to facilitate the compu-tation.Out of a practical concern,we extend the theoretical results to NBQSS with unobserved knots.Finally,simulation studies and two real data analyses reveal three main findings.Firstly,NBQSS usually outperforms other competing curve fitting methods.Secondly,NBQSS consid-ering unobserved knots behaves better than the NBQSS without unobserved knots in terms of estimation accuracy and precision.Thirdly,NBQSS is robust to possible outliers and could provide accurate estimation.展开更多
A new three-parameter discrete distribution called the zero-inflated cosine geometric(ZICG)distribution is proposed for the first time herein.It can be used to analyze over-dispersed count data with excess zeros.The b...A new three-parameter discrete distribution called the zero-inflated cosine geometric(ZICG)distribution is proposed for the first time herein.It can be used to analyze over-dispersed count data with excess zeros.The basic statistical properties of the new distribution,such as the moment generating function,mean,and variance are presented.Furthermore,confidence intervals are constructed by using the Wald,Bayesian,and highest posterior density(HPD)methods to estimate the true confidence intervals for the parameters of the ZICG distribution.Their efficacies were investigated by using both simulation and real-world data comprising the number of daily COVID-19 positive cases at the Olympic Games in Tokyo 2020.The results show that the HPD interval performed better than the other methods in terms of coverage probability and average length in most cases studied.展开更多
The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 t...The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period.展开更多
This paper discussed Bayesian variable selection methods for models from split-plot mixture designs using samples from Metropolis-Hastings within the Gibbs sampling algorithm. Bayesian variable selection is easy to im...This paper discussed Bayesian variable selection methods for models from split-plot mixture designs using samples from Metropolis-Hastings within the Gibbs sampling algorithm. Bayesian variable selection is easy to implement due to the improvement in computing via MCMC sampling. We described the Bayesian methodology by introducing the Bayesian framework, and explaining Markov Chain Monte Carlo (MCMC) sampling. The Metropolis-Hastings within Gibbs sampling was used to draw dependent samples from the full conditional distributions which were explained. In mixture experiments with process variables, the response depends not only on the proportions of the mixture components but also on the effects of the process variables. In many such mixture-process variable experiments, constraints such as time or cost prohibit the selection of treatments completely at random. In these situations, restrictions on the randomisation force the level combinations of one group of factors to be fixed and the combinations of the other group of factors are run. Then a new level of the first-factor group is set and combinations of the other factors are run. We discussed the computational algorithm for the Stochastic Search Variable Selection (SSVS) in linear mixed models. We extended the computational algorithm of SSVS to fit models from split-plot mixture design by introducing the algorithm of the Stochastic Search Variable Selection for Split-plot Design (SSVS-SPD). The motivation of this extension is that we have two different levels of the experimental units, one for the whole plots and the other for subplots in the split-plot mixture design.展开更多
In this work, we study some computational aspects for the Bayesian analysis involving stable distributions. It is well known that, in general, there is no closed form for the probability density function of stable dis...In this work, we study some computational aspects for the Bayesian analysis involving stable distributions. It is well known that, in general, there is no closed form for the probability density function of stable distributions. However, the use of a latent or auxiliary random variable facilitates to obtain any posterior distribution when being related to stable distributions. To show the usefulness of the computational aspects, the methodology is applied to two examples: one is related to daily price returns of Abbey National shares, considered in [1], and the other is the length distribution analysis of coding and non-coding regions in a Homo sapiens chromosome DNA sequence, considered in [2]. Posterior summaries of interest are obtained using the OpenBUGS software.展开更多
This article discusses the Bayesian approach for count data using non-homogeneous Poisson processes, considering different prior distributions for the model parameters. A Bayesian approach using Markov Chain Monte Car...This article discusses the Bayesian approach for count data using non-homogeneous Poisson processes, considering different prior distributions for the model parameters. A Bayesian approach using Markov Chain Monte Carlo (MCMC) simulation methods for this model was first introduced by [1], taking into account software reliability data and considering non-informative prior distributions for the parameters of the model. With the non-informative prior distributions presented by these authors, computational difficulties may occur when using MCMC methods. This article considers different prior distributions for the parameters of the proposed model, and studies the effect of such prior distributions on the convergence and accuracy of the results. In order to illustrate the proposed methodology, two examples are considered: the first one has simulated data, and the second has a set of data for pollution issues at a region in Mexico City.展开更多
A typical blasting vibration wave is a composite wave,and its attenuation law is affected by the type of dominant wave component.The purpose of the present study is to establish an attenuation equation of the peak par...A typical blasting vibration wave is a composite wave,and its attenuation law is affected by the type of dominant wave component.The purpose of the present study is to establish an attenuation equation of the peak particle velocity(PPV),taking into account the attenuation characteristics of P-,S-and R-waves in the blasting vibration wave.Field blasting tests were carried out as a case to specifically apply the proposed equation.In view of the fact that the discrete properties of rock mass will inevitably cause the uncertainty of blasting vibration,we also carried out a probability analysis of PPV uncertainty,and introduced the concept of reliability to evaluate blasting vibration.The results showed that the established attenuation equation had a higher prediction accuracy,and can be considered as a promising equation implemented on more complex sites.The adopted uncertainty analysis method can comprehensively take account of the attenuation law of blasting vibration measured on site and discrete properties of rock masses.The obtained distribution of the PPV uncertainty factor can quantitatively evaluate the reliability of blasting vibration,which is a powerful and necessary supplement to the PPV attenuation equation.展开更多
The inference for the dependent competing risks model is studied and the dependent structure of failure causes is modeled by a Marshall-Olkin bivariate Rayleigh distribution. Under generalized progressive hybrid censo...The inference for the dependent competing risks model is studied and the dependent structure of failure causes is modeled by a Marshall-Olkin bivariate Rayleigh distribution. Under generalized progressive hybrid censoring(GPHC), maximum likelihood estimates are established and the confidence intervals are constructed based on the asymptotic theory. Bayesian estimates and the highest posterior density credible intervals are obtained by using Gibbs sampling. Simulation and a real life electrical appliances data set are used for practical illustration.展开更多
BACKGROUND This study evaluates the American Thyroid Association(ATA)ultrasound(US)classification system for the initial assessment of thyroid nodules to determine if it indeed facilitates clinical decision-making.AIM...BACKGROUND This study evaluates the American Thyroid Association(ATA)ultrasound(US)classification system for the initial assessment of thyroid nodules to determine if it indeed facilitates clinical decision-making.AIM To perform a systematic review and meta-analysis of the diagnostic value of the ATA US classification system for the initial assessment of thyroid nodules.METHODS In accordance with the PRISMA statement for diagnostic test accuracy,we selected articles that evaluated the 2015 ATA US pattern guidelines using a diagnostic gold standard.We analyzed these cases using traditional diagnostic parameters,as well as the threshold approach to clinical decision-making and decision curve analysis.RESULTS We reviewed 13 articles with 8445 thyroid nodules,which were classified according to 2015 ATA patterns.Of these,46.62%were malignant.No cancer was found in any of the ATA benign pattern nodules.The Bayesian analysis post-test probability for cancer in each classification was:(1)Very-low suspicion,0.85%;(2)Low,2.6%;(3)Intermediate,6.7%;and(4)High,40.9%.The net benefit(NB),expressed as avoided interventions,indicated that the highest capacity to avoid unnecessary fine needle aspiration biopsy(FNAB)in the patterns that we studied was 42,31,35,and 43 of every 100 FNABs.The NB calculation for a probability threshold of 11%for each of the ATA suspicion patterns studied is less than that of performing FNAB on all nodules.CONCLUSION These three types of analysis have shown that only the ATA high-suspicion diagnostic pattern is clinically useful,in which case,FNAB should be performed.However,the curve decision analysis has demonstrated that using the ATA US risk patterns to decide which patients need FNAB does not provide a greater benefit than performing FNAB on all thyroid nodules.Therefore,it is likely that a better way to approach the assessment of thyroid nodules would be to perform FNAB on all non-cystic nodules,as the present analysis has shown the ATA risk patterns do not provide an adequate clinical decision-making framework.展开更多
Purpose:The open-access(OA)publishing model can help improve researchers’outreach,thanks to its accessibility and visibility to the public.Therefore,the presentation of female researchers can benefit from the O A pub...Purpose:The open-access(OA)publishing model can help improve researchers’outreach,thanks to its accessibility and visibility to the public.Therefore,the presentation of female researchers can benefit from the O A publishing model.Despite that,little is known about how gender affects OA practices.Thus,the current study explores the effects of female involvement and risk aversion on OA publishing patterns among Vietname se social sciences and humanities.Design/methodology/approach:The study employed Bayesian Mindsponge Framework(BMF)on a dataset of 3,122 Vietnamese social sciences and humanities(SS&H)publications during 2008-2019.The Mindsponge mechanism was specifically used to construct theoretical models,while Bayesian inference was utilized for fitting models.Findings:The result showed a positive association between female participation and OA publishing probability.However,the positive effect of female involvement on OA publishing probability was negated by the high ratio of female researchers in a publication.OA status was negatively associated with the JIF of the journal in which the publication was published,but the relationship was moderated by the involvement of a female researcher(s).The findings suggested that Vietnamese female researchers might be more likely to publish under the OA model in journals with high JIF for avoiding the risk of public criticism.Research limitations:The study could only provide evidence on the association between female involvement and OA publishing probability.However,whether to publish under OA terms is often determined by the first or corresponding authors,but not necessarily gender-based.Practical implications:Systematically coordinated actions are suggested to better support women and promote the OA movement in Vietnam.Originality/value:The findings show the OA publishing patterns of female researchers in Vietnamese SS&H.展开更多
In this paper, we study some robustness aspects of linear regression models of the presence of outliers or discordant observations considering the use of stable distributions for the response in place of the usual nor...In this paper, we study some robustness aspects of linear regression models of the presence of outliers or discordant observations considering the use of stable distributions for the response in place of the usual normality assumption. It is well known that, in general, there is no closed form for the probability density function of stable distributions. However, under a Bayesian approach, the use of a latent or auxiliary random variable gives some simplification to obtain any posterior distribution when related to stable distributions. To show the usefulness of the computational aspects, the methodology is applied to two examples: one is related to a standard linear regression model with an explanatory variable and the other is related to a simulated data set assuming a 23 factorial experiment. Posterior summaries of interest are obtained using MCMC (Markov Chain Monte Carlo) methods and the OpenBugs software.展开更多
This paper presents a hierarchical Bayesian approach to the estimation of components’ reliability (survival) using a Weibull model for each of them. The proposed method can be used to estimation with general survival...This paper presents a hierarchical Bayesian approach to the estimation of components’ reliability (survival) using a Weibull model for each of them. The proposed method can be used to estimation with general survival censored data, because the estimation of a component’s reliability in a series (parallel) system is equivalent to the estimation of its survival function with right- (left-) censored data. Besides the Weibull parametric model for reliability data, independent gamma distributions are considered at the first hierarchical level for the Weibull parameters and independent uniform distributions over the real line as priors for the parameters of the gammas. In order to evaluate the model, an example and a simulation study are discussed.展开更多
The slope stability assessment is a classical problem in geotechnical engineering.This topic have attracted many researcher’s attention and various theoretical models for predicting critical slope heights or safety f...The slope stability assessment is a classical problem in geotechnical engineering.This topic have attracted many researcher’s attention and various theoretical models for predicting critical slope heights or safety factors in the light of the limit equilibrium(LE)method and the kinematical approach of limit analysis(LA)method.Meanwhile,a large number of experimental studies have been conducted to check the slope stability.Using centrifuge testing results,this paper aims to employ Bayesian method to characterize the model uncertainties of the classical three-dimensional rotational failure mechanism proposed by Michalowski and Drescher(2009)to predict critical slope heights in frictional soils,by incorporating the test uncertainties and parameter uncertainties.The obtained results show that the LA three-dimensional rotational failure mechanism overestimates the critical slope height compared with the LE method,and the experimental observational uncertainty has negligible influences on the posterior statistics of model uncertainty.展开更多
Dear Editor,Ever since the first human infection with H7N9 avian influenza virus(AIV)was reported in China in March 2013,there have been five H7N9 AIV pandemics in humans.Wave5 began earlier than the previous four wav...Dear Editor,Ever since the first human infection with H7N9 avian influenza virus(AIV)was reported in China in March 2013,there have been five H7N9 AIV pandemics in humans.Wave5 began earlier than the previous four waves,spread to more districts and counties in affected provinces,and had more confirmed cases(Wang et al.,2017).Human infections展开更多
From a Bayesian analysis of the electric dipole polarizability,the constrained energy of isovector giant dipole resonance,the peak energy of isocalar giant quadrupole resonance,and the constrained energy of isocalar g...From a Bayesian analysis of the electric dipole polarizability,the constrained energy of isovector giant dipole resonance,the peak energy of isocalar giant quadrupole resonance,and the constrained energy of isocalar gi-ant monopole resonance in 208Pb,we extract the isoscalar and isovector effective masses in nuclear matter at satura-tion density ρ0 as m^(*)_(s.0)/m=0.87^(+)_(-004) and m^(*)_(v.0)/m=0.78^(+006)_(-006),respectively,at 90%confdence level.The con-straints obtained on m^(*)_(d.0) and m^(*)_(v.0) lead to a positive isospin splitting of nucleon effective mass in asymmetric nuclear matter of isospin asymmetry σ at ρ0 as m^(*)_(n-p)/m=(0.20^(0.15)_(0.14)σ.In addition,the symmetry energy at the subsatura-tion density ρ^(*)=0.05 fm^(-3) is determined to be E_(sym)(ρ^(*))=16.7±1.3 MeV at 90%confidence level.展开更多
Background:Beijing sub-pedigree 2(BSP2)and T sub-lineage 6(TSL6)are two clades belonging to Beijing and T family of Mycobacterium tuberculosis(MTB),respectively,defined by Bayesian population structure analysis based ...Background:Beijing sub-pedigree 2(BSP2)and T sub-lineage 6(TSL6)are two clades belonging to Beijing and T family of Mycobacterium tuberculosis(MTB),respectively,defined by Bayesian population structure analysis based on 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats(MIRU-VNTR).Globally,over 99%of BSP2 and 89%of TSL6 isolates were distributed in Chongqing,suggesting their possible local adaptive evolution.The objective of this paper is to explore whether BSP2 and TSL6 originated by their local adaptive evolution from the specific isolates of Beijing and T families in Chongqing.Methods:The genotyping data of 16090 MTB isolates were collected from laboratory collection,published literatures and SITVIT database before subjected to Bayesian population structure analysis based on 24-loci MIRUVNTR.Spacer Oligonucleotide Forest(Spoligoforest)and 24-loci MIRU-VNTR-based minimum spanning tree(MST)were used to explore their phylogenetic pathways,with Bayesian demographic analysis for exploring the recent demographic change of TSL6.Results:Phylogenetic analysis suggested that BSP2 and TSL6 in Chongqing may evolve from BSP4 and TSL5,respectively,which were locally predominant in Tibet and Jiangsu,respectively.Spoligoforest showed that Beijing and T families were genetically distant,while the convergence of the MIRU-VNTR pattern of BSP2 and TSL6 was revealed by WebLogo.The demographic analysis concluded that the recent demographic change of TSL6 might take 111.25 years.Conclusions:BSP2 and TSL6 clades might originate from BSP4 and TSL5,respectively,by their local adaptive evolution in Chongqing.Our study suggests MIRU-VNTR be combined with other robust markers for a more comprehensive genotyping approach,especially for families of clades with the same MIRU-VNTR pattern.展开更多
Background:Urinary schistosomiasis has been a major public health problem in Zambia for many years.However,the disease profile may vary in different locale due to the changing ecosystem that contributes to the risk of...Background:Urinary schistosomiasis has been a major public health problem in Zambia for many years.However,the disease profile may vary in different locale due to the changing ecosystem that contributes to the risk of acquiring the disease.The objective of this study was to quantify risk factors associated with the intensity of urinary schistosomiasis infection in school children in Lusaka Province,Zambia,in order to better understand local transmission.Methods:Data were obtained from 1912 school children,in 20 communities,in the districts of Luangwa and Kafue in Lusaka Province.Both individual-and community-level covariates were incorporated into an ordinal logistic regression model to predict the probability of an infection being a certain intensity in a three-category outcome response:0=no infection,1=light infection,and 2=moderate/heavy infection.Random effects were introduced to capture unobserved heterogeneity.Results:Overall,the risk of urinary schistosomiasis was strongly associated with age,altitude at which the child lived,and sex.Weak associations were observed with the normalized difference vegetation index,maximum temperature,and snail abundance.Detailed analysis indicated that the association between infection intensities and age and altitude were category-specific.Particularly,infection intensity was lower in children aged between 5 and 9 years compared to those aged 10 to 15 years(OR=0.72,95%CI=0.51-0.99).However,the age-specific risk changed at different levels of infection,such that when comparing children with light infection to those who were not infected,age was associated with a lower odds(category 1 vs category 0:OR=0.71,95%CI:0.50-0.99),yet such a relation was not significant when considering children who were moderately or heavily infected compared to those with a light or no infection(category 2 vs category 0:OR=0.96,95%CI:0.45-1.64).Overall,we observed that children living in the valley were less likely to acquire urinary schistosomiasis compared to those living in plateau areas(OR=0.48,95%CI:0.16-0.71).However,category-specific effects showed no significant association in category 1(light infection),whereas in category 2(moderate/high infection),the risk was still significantly lower for those living in the valley compared to those living in plateau areas(OR=0.18,95%CI:0.04-0.75).Conclusions:This study demonstrates the importance of understanding the dynamics and heterogeneity of infection in control efforts,and further suggests that apart from the well-researched factors of Schistosoma intensity,various other factors influence transmission.Control programmes need to take into consideration the varying infection intensities of the disease so that effective interventions can be designed.展开更多
基金This study is supported by the Natural Science Foundation of Guangdong,China(2020A1515010756)Project of Administration of Traditional Chinese Medicine of Guangdong Province of China(No.20201074 and No.20221103)the Fundamental Research Funds for the Central Universities(No.21621001).
文摘Objective:Acupuncture methods(including moxibustion)are used frequently in the treatment of herpes zoster.However,the choice is usually made only based on personal experience among different acupuncture methods.This study compared the effectiveness of different acupuncture methods for herpes zoster.Methods:All randomized controlled trials(RCTs)of acupuncture methods for herpes zoster were searched in seven databases including Cochrane Library,Embase,PubMed,Web of Science,Wan-fang,CNKI,and CQVIP database.After screening process,effectiveness rate was extracted from all the included RCTs as primary outcomes.The Bayesian network meta-analysis was conducted by GeMTC 0.14.3,Stata13.0 and Review Man 5.3.Results:39 studies were included,which contained 3,042 participants among 11 interventions.Based on the results of network meta-analysis and ranking probability,fire-acupuncture plus electro-acupuncture is considered to be the most effective method,followed by body-acupuncture plus moxibustion,fire-acupuncture,surround-acupuncture plus moxibustion,moxibustion,surround-acupuncture plus western medicine,surround-acupuncture plus electro-acupuncture,body-acupuncture plus western medicine,surround-acupuncture,western medicine,body-acupuncture.Global and local inconsistency test suggested no significant difference between the results of direct and indirect comparisons.Conclusion:Acupuncture methods might be an effective alternative treatment for herpes zoster and fire-acupuncture plus electro-acupuncture might be considered the best option among the included treatments.However,the results of this study need to be interpreted with caution,because there may still be a problem of small sample size of some studies and interventions.Future research,with a standard methodology and design,requires large-scale trials to validate the effect identified in this meta-analysis.
基金The research is supported by Natural Science Foundation of China[grant number 11671303],[grant number 11201345]Natural Science Foundation of Zhejiang province[grant number LY15G010006]China Postdoctoral Science Founda-tion[grant number 2015M572598].
文摘Most studies of series system assume the causes of failure are independent,which may not hold in practice.In this paper,dependent causes of failure are considered by using a Marshall-Olkin bivariateWeibull distribution.We derived four reference priors based on several grouping orders.Gibbs sampling combined with the rejection sampling algorithm and Metropolis-Hastings algorithm is developed to obtain the estimates of the unknown parameters.The proposed approach is compared with the maximum-likelihood method via simulation.We find that the root-meansquared errors of the Bayesian estimates are much smaller for the case of small sample size,and that the coverage probabilities of the Bayesian estimates are much closer to the nominal levels.Finally,a real data-set is analysed for illustration.
基金The work is supported by the Humanities and Social Sciences Foundation of Ministry of Education,China(Grant No.17YJC910003).
文摘The Wiener process as a degradation model plays an important role in the degradation analysis.In this paper, we propose an objective Bayesian analysis for an acceleration degradation Wienermodel which is subjected to measurement errors. The Jeffreys prior and reference priors underdifferent group orderings are first derived, the propriety of the posteriors is then validated. It isshown that two of the reference priors can yield proper posteriors while the others cannot. A simulation study is carried out to investigate the frequentist performance of the approach comparedto the maximum likelihood method. Finally, the approach is applied to analyse a real data.
基金The project was supported by the National Natural Science Foundation of China[Grant Number 11671146].
文摘In Bayesian quantile smoothing spline[Thompson,P.,Cai,Y.,Moyeed,R.,Reeve,D.,&Stander,J.(2010).Bayesian nonparametric quantile regression using splines.Computational Statistics and Data Analysis,54,1138-1150.],a fixed-scale parameter in the asymmetric Laplace likelihood tends to result in misleading fitted curves.To solve this problem,we propose a new Bayesian quantile smoothing spline(NBQSS),which considers a random scale parameter.To begin with,we justify its objective prior options by establishing one sufficient and one necessary condition of the posterior propriety under two classes of general priors including the invariant prior for the scale component.We then develop partially collapsed Gibbs sampling to facilitate the compu-tation.Out of a practical concern,we extend the theoretical results to NBQSS with unobserved knots.Finally,simulation studies and two real data analyses reveal three main findings.Firstly,NBQSS usually outperforms other competing curve fitting methods.Secondly,NBQSS consid-ering unobserved knots behaves better than the NBQSS without unobserved knots in terms of estimation accuracy and precision.Thirdly,NBQSS is robust to possible outliers and could provide accurate estimation.
基金support from the National Science,Research and Innovation Fund (NSRF)King Mongkut’s University of Technology North Bangkok (Grant No.KMUTNB-FF-65-22).
文摘A new three-parameter discrete distribution called the zero-inflated cosine geometric(ZICG)distribution is proposed for the first time herein.It can be used to analyze over-dispersed count data with excess zeros.The basic statistical properties of the new distribution,such as the moment generating function,mean,and variance are presented.Furthermore,confidence intervals are constructed by using the Wald,Bayesian,and highest posterior density(HPD)methods to estimate the true confidence intervals for the parameters of the ZICG distribution.Their efficacies were investigated by using both simulation and real-world data comprising the number of daily COVID-19 positive cases at the Olympic Games in Tokyo 2020.The results show that the HPD interval performed better than the other methods in terms of coverage probability and average length in most cases studied.
文摘The recent outbreak of COVID-19 has caused millions of deaths worldwide and a huge societal and economic impact in virtually all countries. A large variety of mathematical models to describe the dynamics of COVID-19 transmission have been reported. Among them, Bayesian probabilistic models of COVID-19 transmission dynamics have been very efficient in the interpretation of early data from the beginning of the pandemic, helping to estimate the impact of non-pharmacological measures in each country, and forecasting the evolution of the pandemic in different potential scenarios. These models use probability distribution curves to describe key dynamic aspects of the transmission, like the probability for every infected person of infecting other individuals, dying or recovering, with parameters obtained from experimental epidemiological data. However, the impact of vaccine-induced immunity, which has been key for controlling the public health emergency caused by the pandemic, has been more challenging to describe in these models, due to the complexity of experimental data. Here we report different probability distribution curves to model the acquisition and decay of immunity after vaccination. We discuss the mathematical background and how these models can be integrated in existing Bayesian probabilistic models to provide a good estimation of the dynamics of COVID-19 transmission during the entire pandemic period.
文摘This paper discussed Bayesian variable selection methods for models from split-plot mixture designs using samples from Metropolis-Hastings within the Gibbs sampling algorithm. Bayesian variable selection is easy to implement due to the improvement in computing via MCMC sampling. We described the Bayesian methodology by introducing the Bayesian framework, and explaining Markov Chain Monte Carlo (MCMC) sampling. The Metropolis-Hastings within Gibbs sampling was used to draw dependent samples from the full conditional distributions which were explained. In mixture experiments with process variables, the response depends not only on the proportions of the mixture components but also on the effects of the process variables. In many such mixture-process variable experiments, constraints such as time or cost prohibit the selection of treatments completely at random. In these situations, restrictions on the randomisation force the level combinations of one group of factors to be fixed and the combinations of the other group of factors are run. Then a new level of the first-factor group is set and combinations of the other factors are run. We discussed the computational algorithm for the Stochastic Search Variable Selection (SSVS) in linear mixed models. We extended the computational algorithm of SSVS to fit models from split-plot mixture design by introducing the algorithm of the Stochastic Search Variable Selection for Split-plot Design (SSVS-SPD). The motivation of this extension is that we have two different levels of the experimental units, one for the whole plots and the other for subplots in the split-plot mixture design.
基金partially supported by CNPq-Brazil,by CAPES-Brazil,by INCT em Matematica and also by Pronex Probabilidade e Processos Estocasticos-E-26/170.008/2008-APQ1the financial support from the Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq).
文摘In this work, we study some computational aspects for the Bayesian analysis involving stable distributions. It is well known that, in general, there is no closed form for the probability density function of stable distributions. However, the use of a latent or auxiliary random variable facilitates to obtain any posterior distribution when being related to stable distributions. To show the usefulness of the computational aspects, the methodology is applied to two examples: one is related to daily price returns of Abbey National shares, considered in [1], and the other is the length distribution analysis of coding and non-coding regions in a Homo sapiens chromosome DNA sequence, considered in [2]. Posterior summaries of interest are obtained using the OpenBUGS software.
基金partially supported by grants from Capes,CNPq and FAPESP.
文摘This article discusses the Bayesian approach for count data using non-homogeneous Poisson processes, considering different prior distributions for the model parameters. A Bayesian approach using Markov Chain Monte Carlo (MCMC) simulation methods for this model was first introduced by [1], taking into account software reliability data and considering non-informative prior distributions for the parameters of the model. With the non-informative prior distributions presented by these authors, computational difficulties may occur when using MCMC methods. This article considers different prior distributions for the parameters of the proposed model, and studies the effect of such prior distributions on the convergence and accuracy of the results. In order to illustrate the proposed methodology, two examples are considered: the first one has simulated data, and the second has a set of data for pollution issues at a region in Mexico City.
基金financially supported by National Key R&D Program of China(Grant No.2020YFA0711802)National Nature Science Foundation of China(Grant Nos.51439008 and 51779248).
文摘A typical blasting vibration wave is a composite wave,and its attenuation law is affected by the type of dominant wave component.The purpose of the present study is to establish an attenuation equation of the peak particle velocity(PPV),taking into account the attenuation characteristics of P-,S-and R-waves in the blasting vibration wave.Field blasting tests were carried out as a case to specifically apply the proposed equation.In view of the fact that the discrete properties of rock mass will inevitably cause the uncertainty of blasting vibration,we also carried out a probability analysis of PPV uncertainty,and introduced the concept of reliability to evaluate blasting vibration.The results showed that the established attenuation equation had a higher prediction accuracy,and can be considered as a promising equation implemented on more complex sites.The adopted uncertainty analysis method can comprehensively take account of the attenuation law of blasting vibration measured on site and discrete properties of rock masses.The obtained distribution of the PPV uncertainty factor can quantitatively evaluate the reliability of blasting vibration,which is a powerful and necessary supplement to the PPV attenuation equation.
基金supported by the China Postdoctoral Science Foundation(2019M650260)the National Natural Science Foundation of China(11501433)。
文摘The inference for the dependent competing risks model is studied and the dependent structure of failure causes is modeled by a Marshall-Olkin bivariate Rayleigh distribution. Under generalized progressive hybrid censoring(GPHC), maximum likelihood estimates are established and the confidence intervals are constructed based on the asymptotic theory. Bayesian estimates and the highest posterior density credible intervals are obtained by using Gibbs sampling. Simulation and a real life electrical appliances data set are used for practical illustration.
文摘BACKGROUND This study evaluates the American Thyroid Association(ATA)ultrasound(US)classification system for the initial assessment of thyroid nodules to determine if it indeed facilitates clinical decision-making.AIM To perform a systematic review and meta-analysis of the diagnostic value of the ATA US classification system for the initial assessment of thyroid nodules.METHODS In accordance with the PRISMA statement for diagnostic test accuracy,we selected articles that evaluated the 2015 ATA US pattern guidelines using a diagnostic gold standard.We analyzed these cases using traditional diagnostic parameters,as well as the threshold approach to clinical decision-making and decision curve analysis.RESULTS We reviewed 13 articles with 8445 thyroid nodules,which were classified according to 2015 ATA patterns.Of these,46.62%were malignant.No cancer was found in any of the ATA benign pattern nodules.The Bayesian analysis post-test probability for cancer in each classification was:(1)Very-low suspicion,0.85%;(2)Low,2.6%;(3)Intermediate,6.7%;and(4)High,40.9%.The net benefit(NB),expressed as avoided interventions,indicated that the highest capacity to avoid unnecessary fine needle aspiration biopsy(FNAB)in the patterns that we studied was 42,31,35,and 43 of every 100 FNABs.The NB calculation for a probability threshold of 11%for each of the ATA suspicion patterns studied is less than that of performing FNAB on all nodules.CONCLUSION These three types of analysis have shown that only the ATA high-suspicion diagnostic pattern is clinically useful,in which case,FNAB should be performed.However,the curve decision analysis has demonstrated that using the ATA US risk patterns to decide which patients need FNAB does not provide a greater benefit than performing FNAB on all thyroid nodules.Therefore,it is likely that a better way to approach the assessment of thyroid nodules would be to perform FNAB on all non-cystic nodules,as the present analysis has shown the ATA risk patterns do not provide an adequate clinical decision-making framework.
基金supported by National Foundation for Science and Technology Development 502.01-2018.19.
文摘Purpose:The open-access(OA)publishing model can help improve researchers’outreach,thanks to its accessibility and visibility to the public.Therefore,the presentation of female researchers can benefit from the O A publishing model.Despite that,little is known about how gender affects OA practices.Thus,the current study explores the effects of female involvement and risk aversion on OA publishing patterns among Vietname se social sciences and humanities.Design/methodology/approach:The study employed Bayesian Mindsponge Framework(BMF)on a dataset of 3,122 Vietnamese social sciences and humanities(SS&H)publications during 2008-2019.The Mindsponge mechanism was specifically used to construct theoretical models,while Bayesian inference was utilized for fitting models.Findings:The result showed a positive association between female participation and OA publishing probability.However,the positive effect of female involvement on OA publishing probability was negated by the high ratio of female researchers in a publication.OA status was negatively associated with the JIF of the journal in which the publication was published,but the relationship was moderated by the involvement of a female researcher(s).The findings suggested that Vietnamese female researchers might be more likely to publish under the OA model in journals with high JIF for avoiding the risk of public criticism.Research limitations:The study could only provide evidence on the association between female involvement and OA publishing probability.However,whether to publish under OA terms is often determined by the first or corresponding authors,but not necessarily gender-based.Practical implications:Systematically coordinated actions are suggested to better support women and promote the OA movement in Vietnam.Originality/value:The findings show the OA publishing patterns of female researchers in Vietnamese SS&H.
基金financial support from the Brazilian Institution Conselho Nacional de Desenvolvimento Cientifico e Tecnologico(CNPq).
文摘In this paper, we study some robustness aspects of linear regression models of the presence of outliers or discordant observations considering the use of stable distributions for the response in place of the usual normality assumption. It is well known that, in general, there is no closed form for the probability density function of stable distributions. However, under a Bayesian approach, the use of a latent or auxiliary random variable gives some simplification to obtain any posterior distribution when related to stable distributions. To show the usefulness of the computational aspects, the methodology is applied to two examples: one is related to a standard linear regression model with an explanatory variable and the other is related to a simulated data set assuming a 23 factorial experiment. Posterior summaries of interest are obtained using MCMC (Markov Chain Monte Carlo) methods and the OpenBugs software.
文摘This paper presents a hierarchical Bayesian approach to the estimation of components’ reliability (survival) using a Weibull model for each of them. The proposed method can be used to estimation with general survival censored data, because the estimation of a component’s reliability in a series (parallel) system is equivalent to the estimation of its survival function with right- (left-) censored data. Besides the Weibull parametric model for reliability data, independent gamma distributions are considered at the first hierarchical level for the Weibull parameters and independent uniform distributions over the real line as priors for the parameters of the gammas. In order to evaluate the model, an example and a simulation study are discussed.
基金supported by the National Natural Science Foundation of China(52108388)the science and technology innovation Program of Hunan Province(Project No.2021RC3015).
文摘The slope stability assessment is a classical problem in geotechnical engineering.This topic have attracted many researcher’s attention and various theoretical models for predicting critical slope heights or safety factors in the light of the limit equilibrium(LE)method and the kinematical approach of limit analysis(LA)method.Meanwhile,a large number of experimental studies have been conducted to check the slope stability.Using centrifuge testing results,this paper aims to employ Bayesian method to characterize the model uncertainties of the classical three-dimensional rotational failure mechanism proposed by Michalowski and Drescher(2009)to predict critical slope heights in frictional soils,by incorporating the test uncertainties and parameter uncertainties.The obtained results show that the LA three-dimensional rotational failure mechanism overestimates the critical slope height compared with the LE method,and the experimental observational uncertainty has negligible influences on the posterior statistics of model uncertainty.
基金supported by funding from the National Key Research and Development Program(2016YFD0500201)the CAS Pioneer Hundred Talents Program to Jie Cui
文摘Dear Editor,Ever since the first human infection with H7N9 avian influenza virus(AIV)was reported in China in March 2013,there have been five H7N9 AIV pandemics in humans.Wave5 began earlier than the previous four waves,spread to more districts and counties in affected provinces,and had more confirmed cases(Wang et al.,2017).Human infections
基金Supported in part by the National Natural Science Foundation of China(11905302,11625521)National SKA Program of China(2020SKA0120300)。
文摘From a Bayesian analysis of the electric dipole polarizability,the constrained energy of isovector giant dipole resonance,the peak energy of isocalar giant quadrupole resonance,and the constrained energy of isocalar gi-ant monopole resonance in 208Pb,we extract the isoscalar and isovector effective masses in nuclear matter at satura-tion density ρ0 as m^(*)_(s.0)/m=0.87^(+)_(-004) and m^(*)_(v.0)/m=0.78^(+006)_(-006),respectively,at 90%confdence level.The con-straints obtained on m^(*)_(d.0) and m^(*)_(v.0) lead to a positive isospin splitting of nucleon effective mass in asymmetric nuclear matter of isospin asymmetry σ at ρ0 as m^(*)_(n-p)/m=(0.20^(0.15)_(0.14)σ.In addition,the symmetry energy at the subsatura-tion density ρ^(*)=0.05 fm^(-3) is determined to be E_(sym)(ρ^(*))=16.7±1.3 MeV at 90%confidence level.
基金This work was financially supported by the Department of Science and Technology of Sichuan(18GJHZ0137).
文摘Background:Beijing sub-pedigree 2(BSP2)and T sub-lineage 6(TSL6)are two clades belonging to Beijing and T family of Mycobacterium tuberculosis(MTB),respectively,defined by Bayesian population structure analysis based on 24-loci mycobacterial interspersed repetitive unit-variable number of tandem repeats(MIRU-VNTR).Globally,over 99%of BSP2 and 89%of TSL6 isolates were distributed in Chongqing,suggesting their possible local adaptive evolution.The objective of this paper is to explore whether BSP2 and TSL6 originated by their local adaptive evolution from the specific isolates of Beijing and T families in Chongqing.Methods:The genotyping data of 16090 MTB isolates were collected from laboratory collection,published literatures and SITVIT database before subjected to Bayesian population structure analysis based on 24-loci MIRUVNTR.Spacer Oligonucleotide Forest(Spoligoforest)and 24-loci MIRU-VNTR-based minimum spanning tree(MST)were used to explore their phylogenetic pathways,with Bayesian demographic analysis for exploring the recent demographic change of TSL6.Results:Phylogenetic analysis suggested that BSP2 and TSL6 in Chongqing may evolve from BSP4 and TSL5,respectively,which were locally predominant in Tibet and Jiangsu,respectively.Spoligoforest showed that Beijing and T families were genetically distant,while the convergence of the MIRU-VNTR pattern of BSP2 and TSL6 was revealed by WebLogo.The demographic analysis concluded that the recent demographic change of TSL6 might take 111.25 years.Conclusions:BSP2 and TSL6 clades might originate from BSP4 and TSL5,respectively,by their local adaptive evolution in Chongqing.Our study suggests MIRU-VNTR be combined with other robust markers for a more comprehensive genotyping approach,especially for families of clades with the same MIRU-VNTR pattern.
基金The first author(CS)received a travel award from the Danish Bilharziasis Laboratory,now the DBL-Centre for Health Research and Development,University of Copenhagen,DenmarkThe second author’s(LNK)efforts were partly funded by the University of Namibia.
文摘Background:Urinary schistosomiasis has been a major public health problem in Zambia for many years.However,the disease profile may vary in different locale due to the changing ecosystem that contributes to the risk of acquiring the disease.The objective of this study was to quantify risk factors associated with the intensity of urinary schistosomiasis infection in school children in Lusaka Province,Zambia,in order to better understand local transmission.Methods:Data were obtained from 1912 school children,in 20 communities,in the districts of Luangwa and Kafue in Lusaka Province.Both individual-and community-level covariates were incorporated into an ordinal logistic regression model to predict the probability of an infection being a certain intensity in a three-category outcome response:0=no infection,1=light infection,and 2=moderate/heavy infection.Random effects were introduced to capture unobserved heterogeneity.Results:Overall,the risk of urinary schistosomiasis was strongly associated with age,altitude at which the child lived,and sex.Weak associations were observed with the normalized difference vegetation index,maximum temperature,and snail abundance.Detailed analysis indicated that the association between infection intensities and age and altitude were category-specific.Particularly,infection intensity was lower in children aged between 5 and 9 years compared to those aged 10 to 15 years(OR=0.72,95%CI=0.51-0.99).However,the age-specific risk changed at different levels of infection,such that when comparing children with light infection to those who were not infected,age was associated with a lower odds(category 1 vs category 0:OR=0.71,95%CI:0.50-0.99),yet such a relation was not significant when considering children who were moderately or heavily infected compared to those with a light or no infection(category 2 vs category 0:OR=0.96,95%CI:0.45-1.64).Overall,we observed that children living in the valley were less likely to acquire urinary schistosomiasis compared to those living in plateau areas(OR=0.48,95%CI:0.16-0.71).However,category-specific effects showed no significant association in category 1(light infection),whereas in category 2(moderate/high infection),the risk was still significantly lower for those living in the valley compared to those living in plateau areas(OR=0.18,95%CI:0.04-0.75).Conclusions:This study demonstrates the importance of understanding the dynamics and heterogeneity of infection in control efforts,and further suggests that apart from the well-researched factors of Schistosoma intensity,various other factors influence transmission.Control programmes need to take into consideration the varying infection intensities of the disease so that effective interventions can be designed.
