A family of estimators of population variance in two-occasion rotation patterns

Abstract

In this article, we have considered the problem of estimation of population variance on current (second) occasion in two occasion successive (rotation) sampling. A class of estimators of population variance has been proposed and its asymptotic properties have been discussed. The proposed class of estimators is compared with the sample variance estimator when there is no matching from the previous occasion and the Singh et al. (2013) estimator. Optimum replacement policy is discussed. It has been shown that the suggested estimator is more efficient than the Singh et al. (2013) estimator and a usual unbiased estimator when there is no matching. An empirical study is carried out in support of the present study.     

Fostering secure attachment in low- and middle-income countries: Suggestions for evidence-based interventions

Children struggling with the effects of trauma in low- and middle-income countries (LMIC) face a substantial mental health resource gap that limits their opportunities for positive psychosocial development. Multidisciplinary interventions working to close this gap may benefit from incorporating an empirically supported treatment (EST) into their approach that targets a universal mechanism implicated in resilience, like attachment. ESTs should be selected based on their level of empirical support and cultural adaptability, and then modified on the basis of qualitative evaluations conducted with the local population and stakeholders. This paper will provide an overview of attachment as a mechanism of resilience, a critical analysis of existing attachment-based ESTs, and recommendations for overcoming EST implementation barriers in LMIC.     

Interval estimation in discriminant analysis for large dimension

This paper is concerned with the interval estimation for the log odds of the posterior probability that the observation vector belongs to one of two homoscedastic multivariate normal distributions (Π₁ and Π₂). We give the limiting distribution of the unbiased estimator for the log odds as the sample sizes and the dimension jointly tend to infinity, and approximate the confidence interval based on the asymptotic distribution. Small-scale simulations are performed to check the precision of the approximation.     

‘Pains of imprisonment’: narratives of the women partners and children of the incarcerated

This paper focuses on an important line of inquiry in contemporary criminal justice social work research: the collateral consequences of incarceration in the Chinese context. It gives an insight into the impact of incarceration on families from an insider's perspective. An analysis of interviews with 10 partners and 10 children yielded three major themes concerning the impact of imprisonment: the problems associated with the imprisonment of a family member, the coping strategies used and views on the importance of maintaining family ties. It is hoped that this study will give practical guidance regarding what should be done, and how, to reduce the negative consequences brought about by the absence (temporary or permanent) of the imprisoned on their families, including both their partners and vulnerable children.     

中国黄金市场的风险价值研究

受美国次贷危机以及中国股市低进的影响，对于中国的投资者而言，黄金作为硬通货自然就成为一种很好的实现财富保值增值的投资工具。本文以基于广义误差分布的EGARCH（1，1）模型估计了中国黄金市场的日对数回报VaR值，通过后验测试与统计分析，得出以下结论：EGARCH（1，1）模型（1）能较好地拟合黄金价格的走势（2）杜宾-沃特森（D．W）统计量为1．994103极为接近2，这意味着回报序列的自相关很弱，因此均值方程可以不考虑自回归项。     

An Exposure Assessment of Methyl Mercury via Fish Consumption for the Japanese Population

The objective of this article was to propose an exposure assessment model to describe the relationship between fish consumption and body methyl mercury (MeHg) levels in the Japanese population. Individual MeHg intake was estimated by the summation of species-specific fish consumption multiplied by species-specific fish MeHg levels. The distribution of fish consumed by individuals and the MeHg level in each fish species were assigned based on published data from Japanese government institutions. The probability of MeHg intake for a population was accomplished through a Monte Carlo simulation by the random sampling of fish consumption and species-specific MeHg levels. Internal body MeHg levels in blood and hair were estimated using a one-compartment model. Overall, the mean value of MeHg intake for the Japanese population was estimated to be 6.76 μg/day or 0.14 μg/kg body weight per day (bw/day), while the mean value for the hair mercury level was 2.02 μg/g. Compared with the survey data that tabulated hair mercury levels in a cross-section of the Japanese population, the simulation results matched the hair mercury survey data very well for women, but somewhat underestimated for men and all of the population. This exposure assessment model is a useful attempt at further risk assessment with respect to a risk-benefit analysis.     

A New Goodness-of-Fit Test Based on the Laplace Statistic for a Large Class of NHPP Models

ABSTRACT

Nonhomogeneous Poisson processes (NHPP) provide many models for hardware and software reliability analysis. In order to get an appropriate NHPP model, goodness-of-Fit (GOF for short) tests have to be carried out. For the power-law processes, lots of GOF tests have been developed. For other NHPP models, only the Conditional Probability Integral Transformation (CPIT) test has been proposed. However, the CPIT test is less powerful and cannot be applied to some NHPP models. This article proposes a general GOF test based on the Laplace statistic for a large class of NHPP models with intensity functions of the form αλ(t, β). The simulation results show that this test is more powerful than CPIT test.     

The robustness of the systemwise breusch-godfrey autocorrelation test for non-normal distributed error terms

Using Monte Carlo methods, the properties of systemwise generalisations of the Breusch-Godfrey test for autocorrelated errors are studied in situations when the error terms follow either normal or non-normal distributions, and when these errors follow either AR(1) or MA(1) processes. Edgerton and Shukur (1999) studied the properties of the test using normally distributed error terms and when these errors follow an AR(1) process. When the errors follow a non-normal distribution, the performances of the tests deteriorate especially when the tails are very heavy. The performances of the tests become better (as in the case when the errors are generated by the normal distribution) when the errors are less heavy tailed.     

介电可调薄膜材料及压控微波器件研究

利用介电可调薄膜材料的调谐特性研制的介质压控微波器件高频特性好、功率容量大、响应速度快,还有易集成、功耗小、成本低、可靠性高的特点,相比半导体管、铁氧体以及MEMS器件有明显的优势。该文系统介绍了近年来国内外介电可调薄膜材料及压控微波器件的研究进展,并结合作者的工作评述了介电可调薄膜材料和压控微波器件的应用情况。除研究最为集中的钛酸锶钡BaxSr1-xTiO3(BST)材料,还介绍了具有较高调谐率的铋基焦绿石铌酸铋镁Bi1.5MgNb1.5O7(BMN)薄膜材料,该材料介电损耗低(约0.002),介电常数适中(约86),温度系数小,是一种极具发展前景的微波介电可调材料。