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1.
《Journal of Comparative Economics》2021,49(3):693-714
Informal work is traditionally large in Russia and has further increased in the recent years. We explore the implications of this shift in terms of wage dynamics. Our characterization is based on the estimation of informal pay gaps at the mean and along the wage distribution, relying on the Russian Longitudinal Monitoring Survey for 2003–2017. Our approach comprises three original features: we rely on unconditional quantile effects of informality, we incorporate quantile-specific fixed effects using a tractable approach, and we suggest a treatment of the incidental parameter bias. Over the whole period, informal wage penalties are relatively small and do not suggest heavily segmented labor markets, even at low wage levels. Yet, in the past decade, a substantial negative selection into informal employment and self-employment has taken place, on average and especially at low earnings. Economic downturns and labor market policies have likely contributed to the shakeout of less productive workers in the formal sector, making the low-tier informal sector more of a last resort. 相似文献
2.
供应链竞争力评价指标体系研究 总被引:5,自引:0,他引:5
供应链竞争力是指实施供应链管理的核心企业整合其合作伙伴(供应商、分销商和零售商)的组织结构和业务流程,通过对顾客多变的需求作出比竞争对手更快速、更有效的反应来获取市场竞争优势的能力。通过对影响供应链竞争力的关键因素进行分析,提出了竞争力指标体系的设计原则并建立了供应链竞争力评价指标体系,给出了各指标的含义及计算方法。 相似文献
3.
Nearly exact sample size calculation for powerful non‐randomized tests for differences between binomial proportions 下载免费PDF全文
Stefan Wellek 《Statistica Neerlandica》2015,69(4):358-373
In the case of two independent samples, it turns out that among the procedures taken in consideration, BOSCHLOO'S technique of raising the nominal level in the standard conditional test as far as admissible performs best in terms of power against almost all alternatives. The computational burden entailed in exact sample size calculation is comparatively modest for both the uniformly most powerful unbiased randomized and the conservative non‐randomized version of the exact Fisher‐type test. Computing these values yields a pair of bounds enclosing the exact sample size required for the Boschloo test, and it seems reasonable to replace the exact value with the middle of the corresponding interval. Comparisons between these mid‐N estimates and the fully exact sample sizes lead to the conclusion that the extra computational effort required for obtaining the latter is mostly dispensable. This holds also true in the case of paired binary data (McNemar setting). In the latter, the level‐corrected score test turns out to be almost as powerful as the randomized uniformly most powerful unbiased test and should be preferred to the McNemar–Boschloo test. The mid‐N rule provides a fairly tight upper bound to the exact sample size for the score test for paired proportions. 相似文献
4.
鸟类扑动的翅膀产生的微多普勒包含了目标的尺寸与微动特征信息,可用于鸟类目标参数估计,对探鸟雷达目标识别具有重要意义。首先建立鸟类目标雷达回波模型,推导了鸟翅膀散射点的微多普勒数学表达式,并通过计算回波的自相关函数估计目标扑翼频率;然后对微多普勒表达式进行泰勒级数展开,利用展开系数与扑翼幅度之间的关系得到扑翼幅度的估计值;最后根据半翼展与微多普勒谱宽之间的关系得到半翼展的估计值。仿真实验证明了所提方法的有效性和抗噪性:对扑翼幅度大于30??、半翼展大于0.3 m的目标,在信噪比高于0 dB的噪声环境下估计精度高。 相似文献
5.
裴泽 《石油工业技术监督》2014,30(9):39-42
就苏里格气田苏X区盒8段储层测井二次解释进行了研究。在阐述测井资料预处理的基础上,对储气层孔隙度解释、渗透率解释、泥质含量解释、含气饱和度解释的模型与有效厚度下限的确定作了论述。 相似文献
6.
Adam Lenart 《Scandinavian actuarial journal》2014,2014(3):255-277
The Gompertz distribution is widely used to describe the distribution of adult deaths. Previous works concentrated on formulating approximate relationships to characterise it. However, using the generalised integro-exponential function, exact formulas can be derived for its moment-generating function and central moments. Based on the exact central moments, higher accuracy approximations can be defined for them. In demographic or actuarial applications, maximum likelihood estimation is often used to determine the parameters of the Gompertz distribution. By solving the maximum likelihood estimates analytically, the dimension of the optimisation problem can be reduced to one both in the case of discrete and continuous data. Monte Carlo experiments show that by ML estimation, higher accuracy estimates can be acquired than by the method of moments. 相似文献
7.
One‐sample and multi‐sample tests on the concentration parameter of Fisher‐von Mises‐Langevin distributions on (hyper‐)spheres have been well studied in the literature. However, only little is known about their behaviour under local alternatives, which is due to complications inherent to the curved nature of the parameter space. The aim of the present paper therefore consists in filling that gap by having recourse to the Le Cam methodology, which has recently been adapted from the linear to the spherical setup. We obtain explicit expressions of the powers for the most efficient one‐ and multi‐sample tests. As a nice by‐product, we are also able to write down the powers (against local Fisher‐von Mises‐Langevin alternatives) of the celebrated Rayleigh test of uniformity. A Monte Carlo simulation study confirms our theoretical findings and shows the empirical powers of the above‐mentioned procedures. 相似文献
8.
针对多层微波集成电路设计的微带线层间互连问题,介绍了垂直通孔互连、垂直带条互连和层耦合过渡互连三种高性能的互连方法,并且采用三维电磁仿真软件HFSS对这三种互连结构进行了建模和仿真。仿真结果表明,垂直通孔互连和垂直带条互连在0.1~25 GHz的频宽范围内,回波损耗S11<-20 dB,插入损耗S21>-1 dB,互连性能优良,而层耦合过渡互连在20~68 GHz内回波损耗S11 <-20 dB,插入损耗S21>-1 dB,具有在毫米波频段实现互连的潜力。 相似文献
9.
Demetris Christodoulou 《Applied economics》2018,50(13):1413-1427
Empirical research relying on inputs from published company financial statements ignore the fact that the observed accounting data matrix has been purposefully designed to be rank deficient by means of articulation between stocks and flows. This inherent feature of the data-generating process suggests structural non-identification when both stocks and flows appear in the design matrix and a constraint is required to identify parameters. Much financial research has fallen into this ‘accounting identity trap’ and routinely employs implicit constraints to enable estimation, albeit without acknowledgement of the constraints hence the misleading inferences. This article elucidates the problem of parameter identification under stock-and-flow rank deficiency using existing applications on equity pricing. The focus is on the interpretation of slope coefficients that must be anchored on economically defensible parameter constraints. 相似文献
10.
基于敏捷思想,提出打造敏捷的烟草物流一体化模式,并且提出实现烟草物流一体化的三个环节,首先需要整合业务流程,其次构建高效通畅的信息平台,最后构建上下游企业的协商机制。 相似文献