This paper present a simulation study of an evolutionary algorithms, Particle Swarm Optimization PSO algorithm to optimize likelihood function of ARMA（1, 1） model, where maximizing likelihood function is equivalent ...This paper present a simulation study of an evolutionary algorithms, Particle Swarm Optimization PSO algorithm to optimize likelihood function of ARMA（1, 1） model, where maximizing likelihood function is equivalent to maximizing its logarithm, so the objective function ＇obj.fun＇ is maximizing log-likelihood function. Monte Carlo method adapted for implementing and designing the experiments of this simulation. This study including a comparison among three versions of PSO algorithm “Constriction coefficient CCPSO, Inertia weight IWPSO, and Fully Informed FIPSO”, the experiments designed by setting different values of model parameters al, bs sample size n, moreover the parameters of PSO algorithms. MSE used as test statistic to measure the efficiency PSO to estimate model. The results show the ability of PSO to estimate ARMA＇ s parameters, and the minimum values of MSE getting for COPSO.展开更多
Profile likelihood function is introduced to analyze the uncertainty of hydrometeorological extreme inference and the theory of estimating confidence intervals of the key parameters and quantiles of extreme value dist...Profile likelihood function is introduced to analyze the uncertainty of hydrometeorological extreme inference and the theory of estimating confidence intervals of the key parameters and quantiles of extreme value distribution by profile likelihood function is described.GEV(generalized extreme value)distribution and GP(generalized Pareto)distribution are used respectively to fit the annual maximum daily flood discharge sample of the Yichang station in the Yangtze River and the daily rainfall sample in10 big cities including Guangzhou.The parameters of the models are estimated by maximum likelihood method and the fitting results are tested by probability plot,quantile plot,return level plot and density plot.The return levels and confidence intervals of flood and rainstorm in different return periods are calculated by profile likelihood function.The results show that the asymmetry of the profile likelihood function curve increases with the return period,which can reflect the effect of the length of sample series and return periods on confidence interval.As an effective tool for estimating confidence interval of the key parameters and quantiles of extreme value distribution,profile likelihood function can lead to a more accurate result and help to analyze the uncertainty of extreme values of hydrometeorology.展开更多
针对输油气管道的故障种类多、现场数据无法长期有效保存等问题,提出了一种基于边缘计算和改进随机向量函数链接(random vector functional-link,RVFL)网络的输油气管道故障分类方法。该方法扩展了监控和数据采集(supervisory control a...针对输油气管道的故障种类多、现场数据无法长期有效保存等问题,提出了一种基于边缘计算和改进随机向量函数链接(random vector functional-link,RVFL)网络的输油气管道故障分类方法。该方法扩展了监控和数据采集(supervisory control and data acquisition,SCADA)系统的功能,使其可以存储和访问大量的数据。首先,当输油气管道出现故障时,利用基于模糊似然函数的模糊聚类算法对故障发生前一段时间内的管道压力值进行聚类;然后,提取管道压力值密度特征,将其作为RVFL网络的增强节点,利用改进RVFL网络对故障进行分类。将改进RVFL网络部署在边缘计算模块中,对6种故障进行分类,其准确率可达到96.7%。展开更多
目的探讨应用静息态功能磁共振研究耳鸣患者较为一致的活动异常脑区,从而揭示耳鸣患者脑损伤及功能重塑的神经机制。方法检索1999年1月1日至2023年10月12日采用局部一致性(regional honogeneity,ReHo)及低频振幅(amplitude of low-frequ...目的探讨应用静息态功能磁共振研究耳鸣患者较为一致的活动异常脑区,从而揭示耳鸣患者脑损伤及功能重塑的神经机制。方法检索1999年1月1日至2023年10月12日采用局部一致性(regional honogeneity,ReHo)及低频振幅(amplitude of low-frequency fluctuation,ALFF)、分数低频振幅指标评估耳鸣患者脑功能改变的文献,按照严格的纳排标准,采用激活似然估计法对既往研究中耳鸣患者相对于健康对照组自发脑神经活动异常的脑区进行整合分析。结果共纳入22篇29个研究(耳鸣患者746例,健康对照组653例),联合ALFF、分数低频振幅与ReHo数据Meta分析结果显示,耳鸣患者相对于健康对照组,右颞中回活动增加,并未发现活动减低的脑区;单独ReHo数据分析结果显示,左侧枕中回、左侧后扣带回活动增加;右背外侧额上回、左侧小脑前叶活动减少;单独ALFF数据分析结果显示,耳鸣患者相对于健康对照组未出现任何活动增高或减低的脑区(体素大小≥200 mm^(3),FDR P<0.05)。结论运用激活似然估计法-Meta分析方法证实耳鸣患者多个脑区存在自发活动异常,有助于揭示耳鸣脑功能损伤及重塑的神经病理学基础。展开更多
The likelihood function plays a central role in statistical analysis in relation to information, from both frequentist and Bayesian perspectives. In large samples several new properties of the likelihood in relation t...The likelihood function plays a central role in statistical analysis in relation to information, from both frequentist and Bayesian perspectives. In large samples several new properties of the likelihood in relation to information are developed here. The Arrow-Pratt absolute risk aversion measure is shown to be related to the Cramer-Rao Information bound. The derivative of the log-likelihood function is seen to provide a measure of information related stability for the Bayesian posterior density. As well, information similar prior densities can be defined reflecting the central role of likelihood in the Bayes learning paradigm.展开更多
目的通过荟萃分析探讨慢性颈肩痛(chronic neck and shoulder pain,CNSP)患者的脑自发活动改变特点,从而揭示CNSP可能的中枢神经机制,为后期定位CNSP患者疼痛治疗中枢靶点及客观评估治疗效果奠定基础。方法在线检索14年4月至24年4月发表...目的通过荟萃分析探讨慢性颈肩痛(chronic neck and shoulder pain,CNSP)患者的脑自发活动改变特点,从而揭示CNSP可能的中枢神经机制,为后期定位CNSP患者疼痛治疗中枢靶点及客观评估治疗效果奠定基础。方法在线检索14年4月至24年4月发表在PubMed、Web of Science、EMBase、The Cochrane Library、CNKI、CBM、维普网、万方数据库中采用低频振幅(amplitude of low-frequency fluctuation,ALFF)/比率低频振幅(fractional amplitude of low-frequency fluctuation,fALFF)及局部一致性(regional homogeneity,ReHo)分析方法研究CNSP患者脑自发活动改变的文献。采用激活似然估计法(activation likelihood estimation,ALE)对纳入研究中CNSP患者相对于健康对照组(healthy controls,HCs)脑自发活动出现异常改变的脑区进行元分析。结果共纳入11篇文献,包括6项ALFF/fALFF、5项ReHo研究(CNSP患者445例,健康受试者384例)的数据。分析结果显示:CNSP患者相对于健康对照组(HCs)左侧岛叶皮层和纹状体的脑自发活动增高,而左侧中央前回、左侧中央后回和左侧顶上小叶的脑自发活动减低。结论慢性颈肩痛患者在与感觉、运动、情感以及疼痛的上行传导和下行调控方面相关的多个大脑区域存在脑自发活动的异常改变,这些变化可能是长期的慢性颈肩痛所导致的,本研究为后期通过CNSP患者的脑自发活动改变定位CNSP患者疼痛治疗中枢靶点以及客观评估CNSP治疗效果提供了重要参考。展开更多
In virtue of the notion of likelihood ratio and moment generating function, the limit properties of the sequences of absolutely continuous random variables are studied, and a class of strong limit theorems represented...In virtue of the notion of likelihood ratio and moment generating function, the limit properties of the sequences of absolutely continuous random variables are studied, and a class of strong limit theorems represented by inequalities with random bounds are obtained.展开更多
In this article, we propose a generalized empirical likelihood inference for the parametric component in semiparametric generalized partially linear models with longitudinal data. Based on the extended score vector, a...In this article, we propose a generalized empirical likelihood inference for the parametric component in semiparametric generalized partially linear models with longitudinal data. Based on the extended score vector, a generalized empirical likelihood ratios function is defined, which integrates the within-cluster?correlation meanwhile avoids direct estimating the nuisance parameters in the correlation matrix. We show that the proposed statistics are asymptotically?Chi-squared under some suitable conditions, and hence it can be used to construct the confidence region of parameters. In addition, the maximum empirical likelihood estimates of parameters and the corresponding asymptotic normality are obtained. Simulation studies demonstrate the performance of the proposed method.展开更多
This in virtue of the notion of likelihood ratio and the tool of moment generating function, the limit properties of the sequences of random discrete random variables are studied, and a class of strong deviation theor...This in virtue of the notion of likelihood ratio and the tool of moment generating function, the limit properties of the sequences of random discrete random variables are studied, and a class of strong deviation theorems which represented by inequalities between random variables and their expectation are obtained. As a result, we obtain some strong deviation theorems for Poisson distribution and binomial distribution.展开更多
In this paper,we present a novel particle filter(PF)-based direct position tracking method utilizing multiple distributed observation stations.Traditional passive tracking methods are anchored on repetitive position e...In this paper,we present a novel particle filter(PF)-based direct position tracking method utilizing multiple distributed observation stations.Traditional passive tracking methods are anchored on repetitive position estimation,where the set of consecutive estimates provides the tracking trajectory,such as Two-step and direct position determination methods.However,duplicate estimates can be computationally expensive.In addition,these techniques suffer from data association problems.The PF algorithm is a tracking method that avoids these drawbacks,but the conventional PF algorithm is unable to construct a likelihood function from the received signals of multiple observatories to determine the weights of particles.Therefore,we developed an improved PF algorithm with the likelihood function modified by the projection approximation subspace tracking with deflation(PASTd)algorithm.The proposed algorithm uses the projection subspace and spectral function to replace the likelihood function of PF.Then,the weights of particles are calculated jointly by multiple likelihood functions.Finally,the tracking problem of multiple targets is solved by multiple sets of particles.Simulations demonstrate the effectiveness of the proposed method in terms of computational complexity and tracking accuracy.展开更多
目的通过激活似然估计(ALE)的荟萃分析方法探讨感觉神经性耳聋(SNHL)病人的脑自发活动改变特点,进一步了解SNHL可能存在的脑功能损伤及重塑的神经机制。方法检索2023年8月21日之前Web of Science、PubMed、CNKI、万方医学网、中华医学...目的通过激活似然估计(ALE)的荟萃分析方法探讨感觉神经性耳聋(SNHL)病人的脑自发活动改变特点,进一步了解SNHL可能存在的脑功能损伤及重塑的神经机制。方法检索2023年8月21日之前Web of Science、PubMed、CNKI、万方医学网、中华医学期刊全文数据库中采用局部一致性(ReHo)及低频振幅/分数低频振幅(ALFF/fALFF)分析SNHL病人脑功能改变的文献,按照纳排标准对文献筛选后,采用激活似然估计法(ALE)纳入研究中SNHL病人自发脑神经活动异常的脑区进行Meta分析。结果共纳入22篇29项研究(SNHL 736例,对照487例),其中ReHo研究11项,ALFF/fALFF研究18项。联合ReHo/ALFF/fALFF分析方法且不区分耳聋侧别结果显示SNHL病人左侧丘脑背内侧核自发脑活动增加,左侧颞上回、左侧额下回岛盖部及左侧背外侧前额叶自发脑活动减低。分别依次对左/右耳SNHL病人、ReHo和ALFF/fALFF方法进行ALE分析,结果均未见任何异常活动脑区。结论运用ALE荟萃分析方法证实SNHL病人多个脑区存在自发活动异常,有助于进一步了解SNHL脑功能损伤及重塑的规律及特征,为其后续诊疗评估提供重要依据。展开更多
文摘This paper present a simulation study of an evolutionary algorithms, Particle Swarm Optimization PSO algorithm to optimize likelihood function of ARMA（1, 1） model, where maximizing likelihood function is equivalent to maximizing its logarithm, so the objective function ＇obj.fun＇ is maximizing log-likelihood function. Monte Carlo method adapted for implementing and designing the experiments of this simulation. This study including a comparison among three versions of PSO algorithm “Constriction coefficient CCPSO, Inertia weight IWPSO, and Fully Informed FIPSO”, the experiments designed by setting different values of model parameters al, bs sample size n, moreover the parameters of PSO algorithms. MSE used as test statistic to measure the efficiency PSO to estimate model. The results show the ability of PSO to estimate ARMA＇ s parameters, and the minimum values of MSE getting for COPSO.
基金supported by the National Basic Research Program of China("973" Program)(Grant Nos.2013CB036406,2010CB951102)the National Natural Science Foundation of China(Grant No.51109224)
文摘Profile likelihood function is introduced to analyze the uncertainty of hydrometeorological extreme inference and the theory of estimating confidence intervals of the key parameters and quantiles of extreme value distribution by profile likelihood function is described.GEV(generalized extreme value)distribution and GP(generalized Pareto)distribution are used respectively to fit the annual maximum daily flood discharge sample of the Yichang station in the Yangtze River and the daily rainfall sample in10 big cities including Guangzhou.The parameters of the models are estimated by maximum likelihood method and the fitting results are tested by probability plot,quantile plot,return level plot and density plot.The return levels and confidence intervals of flood and rainstorm in different return periods are calculated by profile likelihood function.The results show that the asymmetry of the profile likelihood function curve increases with the return period,which can reflect the effect of the length of sample series and return periods on confidence interval.As an effective tool for estimating confidence interval of the key parameters and quantiles of extreme value distribution,profile likelihood function can lead to a more accurate result and help to analyze the uncertainty of extreme values of hydrometeorology.
文摘针对输油气管道的故障种类多、现场数据无法长期有效保存等问题,提出了一种基于边缘计算和改进随机向量函数链接(random vector functional-link,RVFL)网络的输油气管道故障分类方法。该方法扩展了监控和数据采集(supervisory control and data acquisition,SCADA)系统的功能,使其可以存储和访问大量的数据。首先,当输油气管道出现故障时,利用基于模糊似然函数的模糊聚类算法对故障发生前一段时间内的管道压力值进行聚类;然后,提取管道压力值密度特征,将其作为RVFL网络的增强节点,利用改进RVFL网络对故障进行分类。将改进RVFL网络部署在边缘计算模块中,对6种故障进行分类,其准确率可达到96.7%。
文摘The likelihood function plays a central role in statistical analysis in relation to information, from both frequentist and Bayesian perspectives. In large samples several new properties of the likelihood in relation to information are developed here. The Arrow-Pratt absolute risk aversion measure is shown to be related to the Cramer-Rao Information bound. The derivative of the log-likelihood function is seen to provide a measure of information related stability for the Bayesian posterior density. As well, information similar prior densities can be defined reflecting the central role of likelihood in the Bayes learning paradigm.
文摘目的通过荟萃分析探讨慢性颈肩痛(chronic neck and shoulder pain,CNSP)患者的脑自发活动改变特点,从而揭示CNSP可能的中枢神经机制,为后期定位CNSP患者疼痛治疗中枢靶点及客观评估治疗效果奠定基础。方法在线检索14年4月至24年4月发表在PubMed、Web of Science、EMBase、The Cochrane Library、CNKI、CBM、维普网、万方数据库中采用低频振幅(amplitude of low-frequency fluctuation,ALFF)/比率低频振幅(fractional amplitude of low-frequency fluctuation,fALFF)及局部一致性(regional homogeneity,ReHo)分析方法研究CNSP患者脑自发活动改变的文献。采用激活似然估计法(activation likelihood estimation,ALE)对纳入研究中CNSP患者相对于健康对照组(healthy controls,HCs)脑自发活动出现异常改变的脑区进行元分析。结果共纳入11篇文献,包括6项ALFF/fALFF、5项ReHo研究(CNSP患者445例,健康受试者384例)的数据。分析结果显示:CNSP患者相对于健康对照组(HCs)左侧岛叶皮层和纹状体的脑自发活动增高,而左侧中央前回、左侧中央后回和左侧顶上小叶的脑自发活动减低。结论慢性颈肩痛患者在与感觉、运动、情感以及疼痛的上行传导和下行调控方面相关的多个大脑区域存在脑自发活动的异常改变,这些变化可能是长期的慢性颈肩痛所导致的,本研究为后期通过CNSP患者的脑自发活动改变定位CNSP患者疼痛治疗中枢靶点以及客观评估CNSP治疗效果提供了重要参考。
基金Supported by the National Nature Science Foundation of China (Grant No. 11101014)the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20101103120016)+4 种基金the Funding Project for Academic Human Resources Development in Institutions of Higher Learning Under the Jurisdiction of Beijing Municipality (Grant No. PHR20110822)Training Programme Foundation for the Beijing Municipal Excellent Talents (Grant No. 2010D005015000002)the Fundamental Research Foundation of Beijing University of Technology (Grant No. X4006013201101)Education Department Science Project of Hebei Province (Grant No. Z2010297)Science Project of Shijiazhuang University of Economics (Grant No. XN0912)
文摘In virtue of the notion of likelihood ratio and moment generating function, the limit properties of the sequences of absolutely continuous random variables are studied, and a class of strong limit theorems represented by inequalities with random bounds are obtained.
文摘In this article, we propose a generalized empirical likelihood inference for the parametric component in semiparametric generalized partially linear models with longitudinal data. Based on the extended score vector, a generalized empirical likelihood ratios function is defined, which integrates the within-cluster?correlation meanwhile avoids direct estimating the nuisance parameters in the correlation matrix. We show that the proposed statistics are asymptotically?Chi-squared under some suitable conditions, and hence it can be used to construct the confidence region of parameters. In addition, the maximum empirical likelihood estimates of parameters and the corresponding asymptotic normality are obtained. Simulation studies demonstrate the performance of the proposed method.
文摘This in virtue of the notion of likelihood ratio and the tool of moment generating function, the limit properties of the sequences of random discrete random variables are studied, and a class of strong deviation theorems which represented by inequalities between random variables and their expectation are obtained. As a result, we obtain some strong deviation theorems for Poisson distribution and binomial distribution.
基金supported by China NSF Grants(62371225,62371227)Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX250590).
文摘In this paper,we present a novel particle filter(PF)-based direct position tracking method utilizing multiple distributed observation stations.Traditional passive tracking methods are anchored on repetitive position estimation,where the set of consecutive estimates provides the tracking trajectory,such as Two-step and direct position determination methods.However,duplicate estimates can be computationally expensive.In addition,these techniques suffer from data association problems.The PF algorithm is a tracking method that avoids these drawbacks,but the conventional PF algorithm is unable to construct a likelihood function from the received signals of multiple observatories to determine the weights of particles.Therefore,we developed an improved PF algorithm with the likelihood function modified by the projection approximation subspace tracking with deflation(PASTd)algorithm.The proposed algorithm uses the projection subspace and spectral function to replace the likelihood function of PF.Then,the weights of particles are calculated jointly by multiple likelihood functions.Finally,the tracking problem of multiple targets is solved by multiple sets of particles.Simulations demonstrate the effectiveness of the proposed method in terms of computational complexity and tracking accuracy.
文摘目的通过激活似然估计(ALE)的荟萃分析方法探讨感觉神经性耳聋(SNHL)病人的脑自发活动改变特点,进一步了解SNHL可能存在的脑功能损伤及重塑的神经机制。方法检索2023年8月21日之前Web of Science、PubMed、CNKI、万方医学网、中华医学期刊全文数据库中采用局部一致性(ReHo)及低频振幅/分数低频振幅(ALFF/fALFF)分析SNHL病人脑功能改变的文献,按照纳排标准对文献筛选后,采用激活似然估计法(ALE)纳入研究中SNHL病人自发脑神经活动异常的脑区进行Meta分析。结果共纳入22篇29项研究(SNHL 736例,对照487例),其中ReHo研究11项,ALFF/fALFF研究18项。联合ReHo/ALFF/fALFF分析方法且不区分耳聋侧别结果显示SNHL病人左侧丘脑背内侧核自发脑活动增加,左侧颞上回、左侧额下回岛盖部及左侧背外侧前额叶自发脑活动减低。分别依次对左/右耳SNHL病人、ReHo和ALFF/fALFF方法进行ALE分析,结果均未见任何异常活动脑区。结论运用ALE荟萃分析方法证实SNHL病人多个脑区存在自发活动异常,有助于进一步了解SNHL脑功能损伤及重塑的规律及特征,为其后续诊疗评估提供重要依据。
