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61.
LetX1,X2, ..., be real-valued random variables forming a strictly stationary sequence, and satisfying the basic requirement of being either pairwise positively quadrant dependent or pairwise negatively quadrant dependent. LetF^ be the marginal distribution function of theXips, which is estimated by the empirical distribution functionFn and also by a smooth kernel-type estimateFn, by means of the segmentX1, ...,Xn. These estimates are compared on the basis of their mean squared errors (MSE). The main results of this paper are the following. Under certain regularity conditions, the optimal bandwidth (in the MSE sense) is determined, and is found to be the same as that in the independent identically distributed case. It is also shown thatn MSE(Fn(t)) andnMSE (F^n(t)) tend to the same constant, asn→∞ so that one can not discriminate be tween the two estimates on the basis of the MSE. Next, ifi(n) = min {k∈{1, 2, ...}; MSE (Fk(t)) ≤ MSE (Fn(t))}, then it is proved thati(n)/n tends to 1, asn→∞. Thus, once again, one can not choose one estimate over the other in terms of their asymptotic relative efficiency. If, however, the squared bias ofF^n(t) tends to 0 sufficiently fast, or equivalently, the bandwidthhn satisfies the requirement thatnh3n→ 0, asn→∞, it is shown that, for a suitable choice of the kernel, (i(n) ?n)/(nhn) tends to a positive number, asn→∞ It follows that the deficiency ofFn(t) with respect toF^n(t),i(n) ?n, is substantial, and, actually, tends to ∞, asn→∞. In terms of deficiency, the smooth estimateF^n(t) is preferable to the empirical distribution functionFn(t) 相似文献
62.
目前国内外对重点实验室的评估主要采用专家评价等软评价方法,较少考虑科技投入和科技产出之间的关联关系。在对国内外重点实验室评估方法进行深入研究的基础上,利用灰色关联度分析指标内在的关联性,将其作为限制条件加入超效率DEA评价模型中,构建了基于灰色关联权重约束的超效率DEA评价模型,并应用于河北省省级重点实验室评估的实证分析。研究结果显示,此模型与传统的CCR模型和超效率DEA模型相比,既可以揭示科技投入和科技产出之间的内在联系,又可以保持DEA评价的客观性,与此同时,还可实现不同实验室评估结果的全排序,使得评估结果更加符合实际。 相似文献
63.
文章基于108个城市2004-2014年市级面板数据测度了长江经济带城市生态效率的时空演变格局,综合而言,长江经济带生态效率水平呈现出波动上升态势,长江流域城市生态效率分化特征明显,湖南、湖北和四川等长江上游城市生态效率较高,长江上、中、下游地区城市生态效率依次递减.对生态效率的影响因素研究表明,科技创新显著地提高了长江经济带的生态效率,经济快速增长降低了城市生态效率,意味着转变经济增长方式、加快科技创新是提高城市生态效率的有效途径.研究还发现,产业结构偏离度有利于提高城市生态效率,而产业升级抑制了城市生态效率的增长,意味着产业升级并不是提高城市生态效率的捷径. 相似文献
64.
陈麟 《浙江大学学报(人文社会科学版)》2018,48(2):227-239
20世纪50年代,国家对手工业进行合作化改造。在此过程中除了为手工业提供必要的技术、资金、原料等方面的支持外,发生最大变化的是手工业的生产关系,国家取代以往众多的商人、工场主,成为实际意义上的“包买商”,试图以社会化大生产的方式来提高手工业的生产力,进而壮大社会主义经济成分。但合作化后期所反映出来的种种问题揭示了只有在生产关系基本适应生产力的情况下,才能真正、有效地推动生产力的发展。 相似文献
65.
This paper is dedicated to the study of the composite quantile regression (CQR) estimations of time-varying parameter vectors for multidimensional diffusion models. Based on the local linear fitting for parameter vectors, we propose the local linear CQR estimations of the drift parameter vectors, and verify their asymptotic biases, asymptotic variances and asymptotic normality. Moreover, we discuss the asymptotic relative efficiency (ARE) of the local linear CQR estimations with respect to the local linear least-squares estimations. We obtain that the local estimations that we proposed are much more efficient than the local linear least-squares estimations. Simulation studies are constructed to show the performance of the estimations proposed. 相似文献
66.
《Journal of Statistical Computation and Simulation》2012,82(4):415-426
This paper considers the problem where the linear discriminant rule is formed from training data that are only partially classified with respect to the two groups of origin. A further complication is that the data of unknown origin do not constitute an observed random sample from a mixture of the two under- lying groups. Under the assumption of a homoscedastic normal model, the overall error rate of the sample linear discriminant rule formed by maximum likelihood from the partially classified training data is derived up to and including terms of the first order in the case of univariate feature data. This first- order expansion of the sample rule so formed is used to define its asymptotic efficiency relative to the rule formed from a completely classified random training set and also to the rule formed from a completely unclassified random set. 相似文献
67.
Data envelopment analysis (DEA) is the most commonly used approach for evaluating healthcare efficiency [B. Hollingsworth, The measurement of efficiency and productivity of health care delivery. Health Economics 17(10) (2008), pp. 1107–1128], but a long-standing concern is that DEA assumes that data are measured without error. This is quite unlikely, and DEA and other efficiency analysis techniques may yield biased efficiency estimates if it is not realized [B.J. Gajewski, R. Lee, M. Bott, U. Piamjariyakul, and R.L. Taunton, On estimating the distribution of data envelopment analysis efficiency scores: an application to nursing homes’ care planning process. Journal of Applied Statistics 36(9) (2009), pp. 933–944; J. Ruggiero, Data envelopment analysis with stochastic data. Journal of the Operational Research Society 55 (2004), pp. 1008–1012]. We propose to address measurement error systematically using a Bayesian method (Bayesian DEA). We will apply Bayesian DEA to data from the National Database of Nursing Quality Indicators® to estimate nursing units’ efficiency. Several external reliability studies inform the posterior distribution of the measurement error on the DEA variables. We will discuss the case of generalizing the approach to situations where an external reliability study is not feasible. 相似文献
68.
本文基于超总体模型研究抽样调查中设计效应的计算问题。首先以随机效应模型为基础,明确了简单随机、二阶段、不等概率和分层抽样对应的超总体模型,进而通过所给模型推导出分层、类集、加权单因素设计效应的计算公式和多因素组合的设计效应计算公式并给出了对应估计量,公式表明:多因素同时存在的组合设计效应等于对应单因素设计效应的乘积。最后,对设计效应的理论值、估计值和真实值之间的关系进行了蒙特卡洛仿真,并利用相对偏倚、相对均方误进行了评价。本文的研究,对复杂抽样设计中正确计算、使用设计效应具有指导意义。 相似文献
69.
《Statistics》2012,46(6):1396-1436
ABSTRACTThe paper deals with an asymptotic relative efficiency concept for confidence regions of multidimensional parameters that is based on the expected volumes of the confidence regions. Under standard conditions the asymptotic relative efficiencies of confidence regions are seen to be certain powers of the ratio of the limits of the expected volumes. These limits are explicitly derived for confidence regions associated with certain plugin estimators, likelihood ratio tests and Wald tests. Under regularity conditions, the asymptotic relative efficiency of each of these procedures with respect to each one of its competitors is equal to 1. The results are applied to multivariate normal distributions and multinomial distributions in a fairly general setting. 相似文献
70.
《Journal of Statistical Computation and Simulation》2012,82(4):491-502
The hazard rate (HR) and mean residual lifetime are two of the most practical and best-known functions in biometry, reliability, statistics and life testing. Recently, the reversed HR function is found to have interesting properties useful in additional areas such as censored data and forensic science. For these three biometric functions, we propose testing methods that they take on a known functional form against that they dominate or are dominated by this known form. This goodness-of-fit-type testing is wider in applications and more interesting than the long-standing testing procedures for exponentiality against the monotonicity of these functions or even the change point problems. This is so since we can test against any choice of the survival distribution and not just exponentiality. For this general testing, we present easy to implement tests and generalize them into classes of statistics that could lead to more powerful and efficient testing. 相似文献