Statistical inference is developed for the analysis of generalized type-Ⅱ hybrid censoring data under exponential competing risks model. In order to solve the problem that approximate methods make unsatisfactory perf...Statistical inference is developed for the analysis of generalized type-Ⅱ hybrid censoring data under exponential competing risks model. In order to solve the problem that approximate methods make unsatisfactory performances in the case of small sample size,we establish the exact conditional distributions of estimators for parameters by conditional moment generating function(CMGF). Furthermore, confidence intervals(CIs) are constructed by exact distributions, approximate distributions as well as bootstrap method respectively,and their performances are evaluated by Monte Carlo simulations. And finally, a real data set is analyzed to illustrate all the methods developed here.展开更多
In this paper,we investigate the convergence of the generalized Bregman alternating direction method of multipliers(ADMM)for solving nonconvex separable problems with linear constraints.This algorithm relaxes the requ...In this paper,we investigate the convergence of the generalized Bregman alternating direction method of multipliers(ADMM)for solving nonconvex separable problems with linear constraints.This algorithm relaxes the requirement of global Lipschitz continuity of differentiable functions that is often seen in many researches,and it incorporates the acceleration technique of the proximal point algorithm(PPA).As a result,the scope of application of the algorithm is broadened and its performance is enhanced.Under the assumption that the augmented Lagrangian function satisfies the Kurdyka-Lojasiewicz inequality,we demonstrate that the iterative sequence generated by the algorithm converges to a critical point of its augmented Lagrangian function when the penalty parameter in the augmented Lagrangian function is sufficiently large.Finally,we analyze the convergence rate of the algorithm.展开更多
Given that challenges on the issue of socioeconomic development faced by countries in sub-Saharan Africa(SSA)have been identified as critical to strengthening the inherent link between governance and socioeconomic con...Given that challenges on the issue of socioeconomic development faced by countries in sub-Saharan Africa(SSA)have been identified as critical to strengthening the inherent link between governance and socioeconomic conditions,this study examines the interconnections between governance and socioeconomic conditions in SSA.With a focus on 25 countries in SSA between 2005 and 2019,we conduct the analysis based on the Panel-Corrected Standard Error and System Generalized Method of Moments estimations and panel causality tests.The results show that SSA does not seem to have the means of effective governance to spur improved socioeconomic conditions.Moreover,the pervasiveness of institutional problems in many countries of SSA has been responsible for the poor socioeconomic conditions in the region.Likewise,governance quality and socioeconomic conditions are found to influence each other.An improvement in socioeconomic conditions could result in better governance quality.On the other hand,governance quality is viewed as a vital ingredient in achieving needed socioeconomic development outcomes.Thus,it is suggested that there is a need for countries in SSA to streamline governing systems toward engendering improved well-being.The introduction and implementation of transformative policies through effective governance are also necessary for ensuring critical structural changes and increasing social service provision.Overall,there should be a proactive identification of ineffective policies and procedures by policymakers to enhance meaningful impacts in the region.展开更多
The boundary knot method(BKM) is a boundary-type meshfree method. Only non-singular general solutions are used during the whole solution procedures. The effective condition number(ECN), which depends on the right-hand...The boundary knot method(BKM) is a boundary-type meshfree method. Only non-singular general solutions are used during the whole solution procedures. The effective condition number(ECN), which depends on the right-hand side vector of a linear system, is considered as an alternative criterion to the traditional condition number. In this paper, the effective condition number is used to help determine the position and distribution of the collocation points as well as the quasi-optimal collocation point numbers. During the solution process, we propose an NMN-search algorithm. Numerical examples show that the ECN is reliable to measure the feasibility of the BKM.展开更多
A judgment criterion to guarantee a point to be a Chen' s approximate zero of Newton method for solving nonlinear equation is sought by dominating sequence techniques. The criterion is based on the fact that the d...A judgment criterion to guarantee a point to be a Chen' s approximate zero of Newton method for solving nonlinear equation is sought by dominating sequence techniques. The criterion is based on the fact that the dominating function may have only one simple positive zero, assuming that the operator is weak Lipschitz continuous, which is much more relaxed and can be checked much more easily than Lipschitz continuous in practice. It is demonstrated that a Chen' s approximate zero may not be a Smale' s approximate zero. The error estimate obtained indicated the convergent order when we use |f(x) | < ε to stop computation in software.The result can also be applied for solving partial derivative and integration equations.展开更多
The empirical Bayes(EB)method based on parametric statistical models such as the negative binomial(NB)has been widely used for ranking sites in the road network safety screening process.In this paper a novel non-param...The empirical Bayes(EB)method based on parametric statistical models such as the negative binomial(NB)has been widely used for ranking sites in the road network safety screening process.In this paper a novel non-parametric EB method for modeling crash frequency data based on Conditional Generative Adversarial Networks(CGAN)is proposed and evaluated over a real-world crash data set.Unlike parametric approaches,there is no need for a pre-specified underlying relationship between dependent and independent variables in the proposed CGAN-EB and they are able to model any types of distributions.The proposed methodology is applied to real-world and simulated crash data sets.The performance of CGAN-EB in terms of model fit,predictive performance and network screening outcomes is compared with the conventional approach(NB-EB)as a benchmark.The results indicate that the proposed CGAN-EB approach outperforms NB-EB in terms of prediction power and hotspot identification tests.展开更多
The study aims to explore the impact of governance and macroeconomic conditions on financial stability in developed and emerging countries.The study sample comprised 122 countries from 2013 to 2020,and a comprehensive...The study aims to explore the impact of governance and macroeconomic conditions on financial stability in developed and emerging countries.The study sample comprised 122 countries from 2013 to 2020,and a comprehensive set of variables was used to construct the financial stability index(FSI).The results of the two-step system GMM analysis,robust with D–K regression,indicate that interest rate,GDP growth,voice and accountability,political stability and absence of violence/terrorism,government effectiveness,regulatory quality,and control of corruption have a positive and statistically significant impact on financial stability.However,inflation,money supply,and the rule of law have adverse and insignificant effects on financial stability.Notably,the findings vary between developed and emerging countries due to differences in governance and macroeconomic conditions and their role in financial stability.The study concludes that regulatory governance and macroeconomic conditions are crucial for financial stability.These outcomes are significant for central banks,academia,and policymakers,as they emphasize the need for stable financial systems and sustainable,balanced growth through governance and macroeconomic conditions.展开更多
为研究层合圆锥壳及其组合壳结构的振动特性,本文基于层合薄壳理论,采用谱元法推导了复合材料层合圆锥壳的基本动刚度矩阵,并利用单个圆锥壳的边界条件和锥顶角变化拼接构建了组合壳体结构的动力学模型。通过与有限元计算(finite elemen...为研究层合圆锥壳及其组合壳结构的振动特性,本文基于层合薄壳理论,采用谱元法推导了复合材料层合圆锥壳的基本动刚度矩阵,并利用单个圆锥壳的边界条件和锥顶角变化拼接构建了组合壳体结构的动力学模型。通过与有限元计算(finite element method,FEM)的固有频率与振动响应对比,验证了本文计算方法和层合圆锥壳动力学模型的正确性。本文分析了圆锥壳两端任意弹性刚度边界、层合铺设角度、铺设层数以及圆锥壳锥顶角等参数对层合圆锥壳振动特性的影响。研究发现铺设角度与弹性边界对固有频率存在影响;随着锥顶角增大,共振峰向低频移动。本文的研究结果可为层合圆锥壳及其组合壳结构的参数化设计和振动计算提供有效的分析工具。展开更多
The conditional generative adversarial network(CGAN)is used in this paper for empirical Bayes(EB)analysis of road crash hotspots.EB is a well-known method for estimating the expected crash frequency of sites(e.g.road ...The conditional generative adversarial network(CGAN)is used in this paper for empirical Bayes(EB)analysis of road crash hotspots.EB is a well-known method for estimating the expected crash frequency of sites(e.g.road segments,intersections)and then prioritising these sites to identify a subset of high priority sites(e.g.hotspots)for additional safety audits/improvements.In contrast to the conventional EB approach,which employs a statis tical model such as the negative binomial model(NB-EB)to model crash frequency data,the recently developed CGAN-EB approach uses a conditional generative adversarial net work,a form of deep neural network,that can model any form of distributions of the crash frequency data.Previous research has shown that the CGAN-EB performs as well as or bet ter than NB-EB,however that work considered only a small range of crash data character istics and did not examine the spatial and temporal transferability.In this paper a series of simulation experiments are devised and carried out to assess the CGAN-EB performance across a wide range of conditions and compares it to the NB-EB.The simulation results show that CGAN-EB performs as well as NB-EB when conditions favor the NB-EB model(i.e.data conform to the assumptions of the NB model)and outperforms NB-EB in experi ments reflecting conditions frequently encountered in practice(i.e.low sample mean crash rates,and when crash frequency does not follow a log-linear relationship with covariates).Also,temporal and spatial transferability of both approaches were evaluated using field data and both CGAN-EB and NB-EB approaches were found to have similar performance.展开更多
以T型耦合板为研究对象,在同时考虑面内振动和面外振动条件下采用改进傅里叶级数方法(Improved Fourier Series Method,IFSM)对其自由振动特性进行了计算分析。板结构的面内振动和面外振动位移函数表示为改进傅里叶级数形式,并引入正弦...以T型耦合板为研究对象,在同时考虑面内振动和面外振动条件下采用改进傅里叶级数方法(Improved Fourier Series Method,IFSM)对其自由振动特性进行了计算分析。板结构的面内振动和面外振动位移函数表示为改进傅里叶级数形式,并引入正弦傅里叶级数以解决边界的不连续或跳跃现象。将位移函数的级数展开系数作为广义坐标,采用Rayleigh-Ritz方法对其进行求解。通过对不同边界条件及耦合连接情况下T型板自由振动特性进行计算,并将之与有限元法结果相比较,验证了该方法的正确性和有效性,为耦合板结构的振动控制提供可靠的理论依据。展开更多
基金Supported by the National Natural Science Foundation of China（71401134, 71571144, 71171164） Supported by the Natural Science Basic Research Program of Shaanxi Province（2015JM1003）+1 种基金 Sup- ported by the Program of International Cooperation and Exchanges in Science and Technology Funded of Shaanxi Province（2016KW-033） Supported by the Scholarship Program of Shanxi Province（2016-015）
文摘Statistical inference is developed for the analysis of generalized type-Ⅱ hybrid censoring data under exponential competing risks model. In order to solve the problem that approximate methods make unsatisfactory performances in the case of small sample size,we establish the exact conditional distributions of estimators for parameters by conditional moment generating function(CMGF). Furthermore, confidence intervals(CIs) are constructed by exact distributions, approximate distributions as well as bootstrap method respectively,and their performances are evaluated by Monte Carlo simulations. And finally, a real data set is analyzed to illustrate all the methods developed here.
文摘In this paper,we investigate the convergence of the generalized Bregman alternating direction method of multipliers(ADMM)for solving nonconvex separable problems with linear constraints.This algorithm relaxes the requirement of global Lipschitz continuity of differentiable functions that is often seen in many researches,and it incorporates the acceleration technique of the proximal point algorithm(PPA).As a result,the scope of application of the algorithm is broadened and its performance is enhanced.Under the assumption that the augmented Lagrangian function satisfies the Kurdyka-Lojasiewicz inequality,we demonstrate that the iterative sequence generated by the algorithm converges to a critical point of its augmented Lagrangian function when the penalty parameter in the augmented Lagrangian function is sufficiently large.Finally,we analyze the convergence rate of the algorithm.
文摘Given that challenges on the issue of socioeconomic development faced by countries in sub-Saharan Africa(SSA)have been identified as critical to strengthening the inherent link between governance and socioeconomic conditions,this study examines the interconnections between governance and socioeconomic conditions in SSA.With a focus on 25 countries in SSA between 2005 and 2019,we conduct the analysis based on the Panel-Corrected Standard Error and System Generalized Method of Moments estimations and panel causality tests.The results show that SSA does not seem to have the means of effective governance to spur improved socioeconomic conditions.Moreover,the pervasiveness of institutional problems in many countries of SSA has been responsible for the poor socioeconomic conditions in the region.Likewise,governance quality and socioeconomic conditions are found to influence each other.An improvement in socioeconomic conditions could result in better governance quality.On the other hand,governance quality is viewed as a vital ingredient in achieving needed socioeconomic development outcomes.Thus,it is suggested that there is a need for countries in SSA to streamline governing systems toward engendering improved well-being.The introduction and implementation of transformative policies through effective governance are also necessary for ensuring critical structural changes and increasing social service provision.Overall,there should be a proactive identification of ineffective policies and procedures by policymakers to enhance meaningful impacts in the region.
基金Supported by the Natural Science Foundation of Anhui Province(1908085QA09)Higher Education Department of the Ministry of Education(201802358008)
文摘The boundary knot method(BKM) is a boundary-type meshfree method. Only non-singular general solutions are used during the whole solution procedures. The effective condition number(ECN), which depends on the right-hand side vector of a linear system, is considered as an alternative criterion to the traditional condition number. In this paper, the effective condition number is used to help determine the position and distribution of the collocation points as well as the quasi-optimal collocation point numbers. During the solution process, we propose an NMN-search algorithm. Numerical examples show that the ECN is reliable to measure the feasibility of the BKM.
文摘A judgment criterion to guarantee a point to be a Chen' s approximate zero of Newton method for solving nonlinear equation is sought by dominating sequence techniques. The criterion is based on the fact that the dominating function may have only one simple positive zero, assuming that the operator is weak Lipschitz continuous, which is much more relaxed and can be checked much more easily than Lipschitz continuous in practice. It is demonstrated that a Chen' s approximate zero may not be a Smale' s approximate zero. The error estimate obtained indicated the convergent order when we use |f(x) | < ε to stop computation in software.The result can also be applied for solving partial derivative and integration equations.
文摘The empirical Bayes(EB)method based on parametric statistical models such as the negative binomial(NB)has been widely used for ranking sites in the road network safety screening process.In this paper a novel non-parametric EB method for modeling crash frequency data based on Conditional Generative Adversarial Networks(CGAN)is proposed and evaluated over a real-world crash data set.Unlike parametric approaches,there is no need for a pre-specified underlying relationship between dependent and independent variables in the proposed CGAN-EB and they are able to model any types of distributions.The proposed methodology is applied to real-world and simulated crash data sets.The performance of CGAN-EB in terms of model fit,predictive performance and network screening outcomes is compared with the conventional approach(NB-EB)as a benchmark.The results indicate that the proposed CGAN-EB approach outperforms NB-EB in terms of prediction power and hotspot identification tests.
文摘The study aims to explore the impact of governance and macroeconomic conditions on financial stability in developed and emerging countries.The study sample comprised 122 countries from 2013 to 2020,and a comprehensive set of variables was used to construct the financial stability index(FSI).The results of the two-step system GMM analysis,robust with D–K regression,indicate that interest rate,GDP growth,voice and accountability,political stability and absence of violence/terrorism,government effectiveness,regulatory quality,and control of corruption have a positive and statistically significant impact on financial stability.However,inflation,money supply,and the rule of law have adverse and insignificant effects on financial stability.Notably,the findings vary between developed and emerging countries due to differences in governance and macroeconomic conditions and their role in financial stability.The study concludes that regulatory governance and macroeconomic conditions are crucial for financial stability.These outcomes are significant for central banks,academia,and policymakers,as they emphasize the need for stable financial systems and sustainable,balanced growth through governance and macroeconomic conditions.
文摘为研究层合圆锥壳及其组合壳结构的振动特性,本文基于层合薄壳理论,采用谱元法推导了复合材料层合圆锥壳的基本动刚度矩阵,并利用单个圆锥壳的边界条件和锥顶角变化拼接构建了组合壳体结构的动力学模型。通过与有限元计算(finite element method,FEM)的固有频率与振动响应对比,验证了本文计算方法和层合圆锥壳动力学模型的正确性。本文分析了圆锥壳两端任意弹性刚度边界、层合铺设角度、铺设层数以及圆锥壳锥顶角等参数对层合圆锥壳振动特性的影响。研究发现铺设角度与弹性边界对固有频率存在影响;随着锥顶角增大,共振峰向低频移动。本文的研究结果可为层合圆锥壳及其组合壳结构的参数化设计和振动计算提供有效的分析工具。
文摘The conditional generative adversarial network(CGAN)is used in this paper for empirical Bayes(EB)analysis of road crash hotspots.EB is a well-known method for estimating the expected crash frequency of sites(e.g.road segments,intersections)and then prioritising these sites to identify a subset of high priority sites(e.g.hotspots)for additional safety audits/improvements.In contrast to the conventional EB approach,which employs a statis tical model such as the negative binomial model(NB-EB)to model crash frequency data,the recently developed CGAN-EB approach uses a conditional generative adversarial net work,a form of deep neural network,that can model any form of distributions of the crash frequency data.Previous research has shown that the CGAN-EB performs as well as or bet ter than NB-EB,however that work considered only a small range of crash data character istics and did not examine the spatial and temporal transferability.In this paper a series of simulation experiments are devised and carried out to assess the CGAN-EB performance across a wide range of conditions and compares it to the NB-EB.The simulation results show that CGAN-EB performs as well as NB-EB when conditions favor the NB-EB model(i.e.data conform to the assumptions of the NB model)and outperforms NB-EB in experi ments reflecting conditions frequently encountered in practice(i.e.low sample mean crash rates,and when crash frequency does not follow a log-linear relationship with covariates).Also,temporal and spatial transferability of both approaches were evaluated using field data and both CGAN-EB and NB-EB approaches were found to have similar performance.
文摘以T型耦合板为研究对象,在同时考虑面内振动和面外振动条件下采用改进傅里叶级数方法(Improved Fourier Series Method,IFSM)对其自由振动特性进行了计算分析。板结构的面内振动和面外振动位移函数表示为改进傅里叶级数形式,并引入正弦傅里叶级数以解决边界的不连续或跳跃现象。将位移函数的级数展开系数作为广义坐标,采用Rayleigh-Ritz方法对其进行求解。通过对不同边界条件及耦合连接情况下T型板自由振动特性进行计算,并将之与有限元法结果相比较,验证了该方法的正确性和有效性,为耦合板结构的振动控制提供可靠的理论依据。
