Approximation of the Bivariate Renewal Function

Recently, Kambo and his co-researchers (2012) proposed a method of approximation for evaluating the one-dimensional renewal function based on the first three moments. Their method is simple and elegant, which gives exact values for well-known distributions. In this article, we propose an analogous method for the evaluation of bivariate renewal function based on the first two moments of the variables and their joint moment. The proposed method yields exact results for certain widely used bivariate distributions like bivariate exponential distribution, bivariate Weibull distributions, and bivariate Pareto distributions. An illustrative example in the form of a two-dimensional warranty problem is considered and comparisons of our method are made with the results of other models.     

Towards Uniformly Efficient Trend Estimation Under Weak/Strong Correlation and Non‐stationary Volatility

In this paper, we consider the deterministic trend model where the error process is allowed to be weakly or strongly correlated and subject to non‐stationary volatility. Extant estimators of the trend coefficient are analysed. We find that under heteroskedasticity, the Cochrane–Orcutt‐type estimator (with some initial condition) could be less efficient than Ordinary Least Squares (OLS) when the process is highly persistent, whereas it is asymptotically equivalent to OLS when the process is less persistent. An efficient non‐parametrically weighted Cochrane–Orcutt‐type estimator is then proposed. The efficiency is uniform over weak or strong serial correlation and non‐stationary volatility of unknown form. The feasible estimator relies on non‐parametric estimation of the volatility function, and the asymptotic theory is provided. We use the data‐dependent smoothing bandwidth that can automatically adjust for the strength of non‐stationarity in volatilities. The implementation does not require pretesting persistence of the process or specification of non‐stationary volatility. Finite‐sample evaluation via simulations and an empirical application demonstrates the good performance of proposed estimators.     

Interval estimation for conformance proportions of multiple quality characteristics

A conformance proportion is an important and useful index to assess industrial quality improvement. Statistical confidence limits for a conformance proportion are usually required not only to perform statistical significance tests, but also to provide useful information for determining practical significance. In this article, we propose approaches for constructing statistical confidence limits for a conformance proportion of multiple quality characteristics. Under the assumption that the variables of interest are distributed with a multivariate normal distribution, we develop an approach based on the concept of a fiducial generalized pivotal quantity (FGPQ). Without any distribution assumption on the variables, we apply some confidence interval construction methods for the conformance proportion by treating it as the probability of a success in a binomial distribution. The performance of the proposed methods is evaluated through detailed simulation studies. The results reveal that the simulated coverage probability (cp) for the FGPQ-based method is generally larger than the claimed value. On the other hand, one of the binomial distribution-based methods, that is, the standard method suggested in classical textbooks, appears to have smaller simulated cps than the nominal level. Two alternatives to the standard method are found to maintain their simulated cps sufficiently close to the claimed level, and hence their performances are judged to be satisfactory. In addition, three examples are given to illustrate the application of the proposed methods.     

雄安新区科技企业创新能力评价研究

科技企业是实现科技创新的驱动者和科技成果转化的重要载体,也是推动研究开发的重要参与者,科学评价科技企业创新能力有助于企业自身不断发展壮大。在分析国内外新区科技企业创新驱动发展相关理论研究的基础上,从研发投入、研发基础、研发效益和现代科技四个角度,运用层次分析法构建科技企业创新能力评价系统,并通过实证分析说明评价系统的可靠性;根据评价系统测算出现阶段雄安新区科技企业创新能力,通过与成熟新区科技企业的比较,发现其短板和不足,力图为决策者科学合理评价、管理科技企业创新发展提供有益参考。     

Modeling spatial overdispersion via the generalized Waring point process

Modeling spatial overdispersion requires point process models with finite‐dimensional distributions that are overdisperse relative to the Poisson distribution. Fitting such models usually heavily relies on the properties of stationarity, ergodicity, and orderliness. In addition, although processes based on negative binomial finite‐dimensional distributions have been widely considered, they typically fail to simultaneously satisfy the three required properties for fitting. Indeed, it has been conjectured by Diggle and Milne that no negative binomial model can satisfy all three properties. In light of this, we change perspective and construct a new process based on a different overdisperse count model, namely, the generalized Waring (GW) distribution. While comparably tractable and flexible to negative binomial processes, the GW process is shown to possess all required properties and additionally span the negative binomial and Poisson processes as limiting cases. In this sense, the GW process provides an approximate resolution to the conundrum highlighted by Diggle and Milne.     

Teaching technologies for immigrant children: an exploratory study of elementary school teachers in Russia*

ABSTRACT

Educational institutions are an important setting where psychological, pedagogical, sociocultural, and language adaptation of immigrant children occurs. A number of teaching strategies, practices, approaches, and methods have been described in the literature. In the Russian context, such strategies have been called ‘technologies’. The purpose of the present exploratory study was to describe teaching technologies used by teachers in Russia when working with immigrant students in elementary schools. Responses of forty-five elementary school teachers to open-ended questions describing technologies they use when teaching children with migration backgrounds were analyzed using content analysis. Findings suggest that Russian elementary school teachers used ethno-cultural group, communicative technologies, games, individualized instruction, and differentiated teaching. Many approaches mentioned can be used inclusively with groups of immigrant and non-immigrant students. Importantly, while teachers supplemented classroom instruction with additional Russian language lessons, none mentioned specific techniques for teaching Russian as a non-native language. These findings are discussed in relation to teaching strategies described in the international literature focused on migrant students. Finally, implications for further research are discussed.     

运用心理学移情原理消除师生的情感障碍

英语教学的成败是诸多因素相互作用的结果 ,但无论这些因素多么错综复杂 ,主要还是来自教和学两方面。教师和学生能否在教学中相互理解从而形成互动是教学成败的关键。文章将着重讨论师生间营造互动关系中的两个重要环节———情感与移情     

计算机与学术写作(英文)

深大外语系把若干计算机软件应用于英语专业本科学生的写作课教材系列。这不仅有助于学生自修写作技巧,且能为教师节省大量时间,使教师有可能对学生作更多的个别辅导。同时,学生在上写作课的过程中还能掌握一种使用计算机的实际技能。近十年来,中国的飞速发展是史无前例的。西方的技术发展史对中国虽然有启迪作用,但其实际要求与中国相去甚远。在这个意义上,深大的尝试对全中国均具有示范意义。