On a class exhibiting trend change in average failure rate

Abstract

Weak convergence and moment convergence issues are investigated for the New Better than Average Failure Rate (NBAFR) family (introduced by Loh (1984 Loh, W. Y. 1984. A new generalization of the class of NBU distributions. IEEE Transactions on Reliability R-33 :97–113[Crossref], [Web of Science ®] , [Google Scholar])). We explore the validity of these results in the context of a more general ageing class that we introduce. We prove some new properties of this class and derive its interrelationships with other non-monotonic ageing families. Reliability and moment bounds are obtained and an interesting characterization of exponentiality is proved. Special cases of our results lead to new theorems for the NBAFR class. Finally weak convergence and related issues are established for this class.     

约束优化问题的异步并行拟牛顿方法

提出了一种求解等式约束优化问题的异步并行拟牛顿方法 .若假设目标函数 f和约束函数h至少三次连续可微 ,且△h(x)对任意x∈Rn 均为满秩矩阵 ,证明了所提出的异步并行算法是 q—超线性收敛的 .     

Deconvolution with supersmooth distributions

Nonparametric deconvolution problems require one to recover an unknown density when the data are contaminated with errors. Optimal global rates of convergence are found under the weighted L_p-loss (1 ≤ p ≤ ∞). It appears that the optimal rates of convergence are extremely low for supersmooth error distributions. To resolve this difficulty, we examine how high the noise level can be for deconvolution to be feasible, and for the deconvolution estimate to be as good as the ordinary density estimate. It is shown that if the noise level is not too high, nonparametric Gaussian deconvolution can still be practical. Several simulation studies are also presented.     

On Rates of Convergence for Bayesian Density Estimation

Abstract.  We consider the problem of estimating a compactly supported density taking a Bayesian nonparametric approach. We define a Dirichlet mixture prior that, while selecting piecewise constant densities, has full support on the Hellinger metric space of all commonly dominated probability measures on a known bounded interval. We derive pointwise rates of convergence for the posterior expected density by studying the speed at which the posterior mass accumulates on shrinking Hellinger neighbourhoods of the sampling density. If the data are sampled from a strictly positive, α -Hölderian density, with α  ∈ ( 0,1] , then the optimal convergence rate n^{− α / (2 α +1)} is obtained up to a logarithmic factor. Smoothing histograms by polygons, a continuous piecewise linear estimator is obtained that for twice continuously differentiable, strictly positive densities satisfying boundary conditions attains a rate comparable up to a logarithmic factor to the convergence rate n ^−4/5 for integrated mean squared error of kernel type density estimators.     

块Jacobi迭代阵的收敛性

研究大型线性方程组迭代解法中分块ＪＡＣＯＢＩ迭代阵的收敛性。采用块矩阵分析方法和谱半径降维估计法得到块Ｊａｃｏｂｉ迭代阵收敛的实用充分条件。     

经济收敛理论与检验方法研究综述

在大量文献研究的基础上,对收敛问题的产生及收敛概念的发展作了全面概括,并对绝对收敛、条件收敛、俱乐部收敛和σ收敛作了深入辨析,对各种识别方法作了全面归纳。归纳了对世界大多数国家和地区数据所作识别的结果。还从收敛理论与传统理论的冲突与协调方面作了深入分析。最后对近年收敛研究的深化与扩展研究的趋势作了概括。     

服务产品价格的范围与振荡收敛性研究

服务提供商占有服务创造的价值的问题必然涉及到对服务产品的定价。通过使用价格和服务量共同来描述服务价值的创造与分配,用服务产品的价格的确定来实现价值的分配,用不同的价格决定权和博弈顺序来确定服务产品的价格范围,然后寻求一种服务产品价格的振荡系统,使得服务产品的价格最终收敛于总价值创造最高的价格。     

中国粮食生产潜能分析：一个基于“俱乐部 收敛”的视点

我国的粮食单产存在显著的地区差异,不同地区粮食单产的收敛分析有助于预测粮食生产潜能。对1980年至2012年全国30个省区市稻谷、玉米、小麦三种主粮单产数据的收敛分析发现,传统收敛β收敛与σ收敛的分析结果相互冲突,并且与现实不符。而俱乐部收敛分析发现,稻谷单产全国范围内趋于收敛;玉米单产同样在全国范围内收敛;但小麦单产则不存在总体收敛趋势,而是收敛于三个不同的俱乐部。进一步以“俱乐部”内最高单产为参照测算三种主粮历年的生产潜能,预测结果显示,实际产量与潜在产量的差距在不断缩小;三种主粮在2012年的潜在总产量为6.6万亿吨,仍比实际产量高26%;初步估计,未来10—20年之内,三种主粮的增产潜能会保持在10%以上。     

Europeanisation and the Youth Guarantee: The case of France

In 2013, the European Council approved the Youth Guarantee (YG) to counteract youth unemployment. Because of its specific features, the YG is useful for understanding whether the EU has triggered policy change in national youth unemployment policies. Contrary to most of the literature on similar topics, we focused in this study on the effect of this specific European measure rather than on broader EU strategies or policies. The study contributes to the literature by qualifying the degree of fit/misfit and suggesting a counterfactual analysis, using the case of France. We first situate the article within the broader Europeanisation debate and present our research design. The second section introduces the policy structure of the YG and investigates youth unemployment policy in France, prior to and after the European initiative. The third section discusses whether the French youth unemployment policy would have been developed in the same way without the YG. A final section concludes.     

Macroeconomic asymmetry in the Eurozone before and after the Global Financial Crisis: An appraisal of the role of the ECB

The launch of the euro in 1999 was assumed to enhance macroeconomic convergence among EMU economies. We test this hypothesis from a comparative perspective, by calculating different indices to measure the degree of macroeconomic dispersion within the Eurozone, the UK and the USA (1999–2019). We use common factor models to produce a single index for each monetary area out of different measures of dispersion. These indices can be used to inform on the degree of optimality of a monetary area. Our results show that macroeconomic dispersion in the Eurozone increased notably even before 2007 and it took significantly longer to return to pre-crisis levels, as compared to the UK and the USA. The paper shows the critical role played by the ECB’s asset purchases programmes in reducing macroeconomic divergences among EMU member states since 2015.