基于混频数据的实体经济与金融市场时变溢出效应研究

本文基于混频VAR模型分析了中国实体经济与股票市场、债券市场之间的时变溢出效应。结果显示,实体经济与股票市场、债券市场之间收益率与波动率的溢出效应呈现显著的时变特征,溢出效应在金融危机期间呈现快速上升趋势,而后呈现下降态势,且易受到极端事件的影响;在大部分考察时期内存在股票市场向实体经济的波动率溢出效应,而债券市场相对于实体经济则从考察初期波动率溢出效应的净输入方转化为中后期的波动率溢出效应的净输出方。进一步分析收益率与波动率总溢出指数的影响因素,结果发现,极端事件、宏观经济代理变量和期限利差对于溢出效应具有正向影响,泰德利差对波动率总溢出指数具有负向影响,而投资者情绪指数对收益率总溢出指数具有负向影响。     

Visualizing uncertainty in reliability functions with application to aero engine overhaul

Summary.  We propose an approach for estimating the date of lost confidence of jet engines, which are devices with multiple components subject to disruption. A mixed Weibull distribution is estimated from a large data set subject to censoring at various times. Parametric uncertainty is derived analytically and mapped visually onto the functions of use in reliability theory, including the hazard function. We demonstrate the use of the method on a database of disruption times for components in 325 jet engines.     

What are Children's Centres? The Development of CC Services, 2004–20081

Children's centres are intended to be a mainstream, universal service. They began in 2004 and their origins are diverse. Some replaced various forms of local provision, most notably Sure Start programmes; others were established from scratch. Issues for exploratory empirical work have been identified from the guidance issued by central government. Using interview data from three urban local authorities, this article explores the nature of the ‘core offer’ that centres are expected to provide and the way in which they have pursued the goal of integrating staff and services. The article highlights the problems of balancing a focus on the child and on the parent; of reconciling childcare provision as part of the employability agenda and as a means to educational achievement for the child; of permitting local variation while achieving consistency; of the role of monitoring in relation to developing good practice; and of achieving integration in a mixed economy of care. We find that despite the greater specification of the core offer for children's centres compared to that for Sure Start, there are substantial differences between children's centres in terms of services, while the mixed economy of provision poses considerable challenges to the goal of integration.     

A comparison of inference procedures in unbalanced split-plot designs

Several procedures for constructing confidence intervals and testing hypotheses about fixed effects in unbalanced split-plot experiments are described in this paper. These procedures can also be used for unbalanced repeated measures experiments when the repeated measures satisfy the Huyhn-Feldt (1970) conditions. A number of these procedures require that the whole plot error mean square has a distribution proportional to a chi-square distribution and that it be independent of estimators of the parameter functions. Often, neither of these conditions are met in unbalanced split-plot experiments. Simulation studies of a small design of eight observations and larger designs with 34 to 48 observations are used to investigate the performance of the different procedures.     

A mixed membership model-based measure for subgroup integration in social networks

Social networks analysis often involves quantifying subgroup structure in which tie density is greater among nodes in the same subgroup than between subgroups. One such measure, subgroup insularity or segregation, is the extent that subgroups are separate from each other. We introduce a new measure, γ, which is a parameter from the mixed membership stochastic blockmodel (MMSBM; Airoldi et al., 2008), and differs from many existing measures in that γ does not depend on node membership. We compare this measure to several well-known measures and use simulation studies and real data analysis to provide insight into how this measure can be used in practice.     

Income Security During Sickness Absence. What Do British Middle‐classes Do?

Income maintenance during sickness absence is an under‐researched field within social policy analysis, and yet it is conducive to exploring the interplay between statutory, corporate and private forms of income protection. Drawing on original qualitative interview data, the article shows that British middle‐class couples largely ignore or dismiss public provision, which is due to a relatively low level of sickness benefits, but also based on misconceptions about social rights and the role of employers as mandatory (and voluntary) sick pay providers. Despite a considerable degree of mistrust, mortgage‐related private sickness insurance mattered to some extent, although this does not necessarily reflect policyholders’ strategic choices vis à vis current household needs for income security. Other potential sources of income replacement, such as savings, are relied on much less. In general, the analysis shows a heavy middle‐class reliance on, and strong confidence in, employer‐based sickness pay. This finding may be contrasted with questions about the sustainability of voluntary corporate provision, as well as its capacity to provide income security for the workforce as a whole.     

MULTI-STAGE KERNEL-BASED CONDITIONAL QUANTILE PREDICTION IN TIME SERIES

We present a multi-stage conditional quantile predictor for time series of Markovian structure. It is proved that at any quantile level, p ∈ (0, 1), the asymptotic mean squared error (MSE) of the new predictor is smaller than the single-stage conditional quantile predictor. A simulation study confirms this result in a small sample situation. Because the improvement by the proposed predictor increases for quantiles at the tails of the conditional distribution function, the multi-stage predictor can be used to compute better predictive intervals with smaller variability. Applying this predictor to the changes in the U.S. short-term interest rate, rather smooth out-of-sample predictive intervals are obtained.     

A comparison of methods for the fitting of generalized additive models

There are several procedures for fitting generalized additive models, i.e. regression models for an exponential family response where the influence of each single covariates is assumed to have unknown, potentially non-linear shape. Simulated data are used to compare a smoothing parameter optimization approach for selection of smoothness and of covariates, a stepwise approach, a mixed model approach, and a procedure based on boosting techniques. In particular it is investigated how the performance of procedures is linked to amount of information, type of response, total number of covariates, number of influential covariates, and extent of non-linearity. Measures for comparison are prediction performance, identification of influential covariates, and smoothness of fitted functions. One result is that the mixed model approach returns sparse fits with frequently over-smoothed functions, while the functions are less smooth for the boosting approach and variable selection is less strict. The other approaches are in between with respect to these measures. The boosting procedure is seen to perform very well when little information is available and/or when a large number of covariates is to be investigated. It is somewhat surprising that in scenarios with low information the fitting of a linear model, even with stepwise variable selection, has not much advantage over the fitting of an additive model when the true underlying structure is linear. In cases with more information the prediction performance of all procedures is very similar. So, in difficult data situations the boosting approach can be recommended, in others the procedures can be chosen conditional on the aim of the analysis.     

SMALL AREA ESTIMATION USING SURVEY WEIGHTS WITH FUNCTIONAL MEASUREMENT ERROR IN THE COVARIATE

Nested error linear regression models using survey weights have been studied in small area estimation to obtain efficient model‐based and design‐consistent estimators of small area means. The covariates in these nested error linear regression models are not subject to measurement errors. In practical applications, however, there are many situations in which the covariates are subject to measurement errors. In this paper, we develop a nested error linear regression model with an area‐level covariate subject to functional measurement error. In particular, we propose a pseudo‐empirical Bayes (PEB) predictor to estimate small area means. This predictor borrows strength across areas through the model and makes use of the survey weights to preserve the design consistency as the area sample size increases. We also employ a jackknife method to estimate the mean squared prediction error (MSPE) of the PEB predictor. Finally, we report the results of a simulation study on the performance of our PEB predictor and associated jackknife MSPE estimator.