新时期以来留学归国人员社会影响力研究

留学归国人员是一支视野更为宽阔、思路更为开拓、在学术上有所建树的群体。文章分析了新时期的留学归国人员的发展特征和社会影响力,认为要更大地发挥留学归国人员的作用,一方面要加强对归国留学人员的引导,克服其自身的不足;另一方面应提供合理而行之有效的政策和客观环境。     

汽车行人碰撞多体动力学仿真与抛距模型研究

汽车与行人碰撞是我国道路交通事故的主要类型之一,该类事故在所有事故中致死率最高且与人们的安全出行密切相关,受到民众的广泛关注。然而传统的事故分析方法在此类事故的处理上存在较大困难。文章以多体动力学理论为基础,以PC CRASH为平台,建立了多刚体数字化行人模型,通过设定代表身体各部分的属性（外形、质量、刚度、摩擦系数等）来定义行人特征。并将模型与国外某实车碰撞试验对比验证其可靠性。通过对仿真结果的回归分析得出了车速 抛距模型,为该类交通事故处理提供了数据参考。     

美国海洋溢油事件的社会学研究

海洋溢油是工业社会的产物,凸显了现代风险社会的特质。它不仅会产生严重的环境与经济影响,也会产生深刻的社会与文化影响。美国海洋溢油事件的社会学研究可分为"根源论"、"影响论"和"博弈论",分别探讨了溢油事件的社会根源、社会文化影响与心理影响及其康复以及权力博弈等议题。美国海洋溢油事件的社会学研究具有很强的追踪性和深入性。随着海洋开发进程的加快,中国溢油事件已经屡见不鲜,对社会运行产生着深刻影响。鉴于此,中国社会学界需要增加学术自觉意识,积极扭转海洋溢油事件中社会学话语体系缺失的局面。     

Optimal CUSUM and adaptive CUSUM charts with auxiliary information for process mean

The CUSUM chart is good enough to detect small-to-moderate shifts in the process parameter(s) as it can be optimally designed to detect a particular shift size. The adaptive CUSUM (ACUSUM) chart provides good detection over a range of shift sizes because of its ability to update the reference parameter using the estimated process shift. In this paper, we propose auxiliary-information-based (AIB) optimal CUSUM (OCUSUM) and ACUSUM charts, named AIB-OCUSUM and AIB-ACUSUM charts, using a difference estimator of the process mean. The performance comparisons between existing and proposed charts are made in terms of the average run length (ARL), extra quadratic loss and integral relative ARL measures. It is found that the AIB-OCUSUM and AIB-ACUSUM charts are more sensitive than the AIB-CUSUM and ACUSUM charts, respectively. Moreover, the AIB-ACUSUM chart surpasses the AIB-OCUSUM chart when detecting a range of mean shift sizes. Illustrative examples are given to support the theory.     

Spatial Analyses of the Impact of Temporary Assistance for Needy Families on Child Neglect Caseloads During the Great Recession

Loss of market income to families is recognized as a major risk factor of child neglect. In the 2008 recession, some poor families replaced their market incomes with cash assistance from Temporary Assistance for Needy Families (TANF). Using secondary data for 42 contiguous jurisdictions and DC, we examined the relationship between increases in TANF caseloads and changes in substantiated child neglect cases in each of the contiguous jurisdiction’s 2008 recession. Key findings suggest that reductions in child neglect cases in the presence of increasing TANF caseloads were more profound in about half the states than any increases in child neglect cases found in the remainder of the states. Applying Exploratory Spatial Data Analysis tools, local spatial clusters were found in four neighboring states in the Midwest-South corridor suggesting that child neglect increases were similar and substantial across these four states. Our findings provide important information to stakeholders who may want to better target federal resources to specific geographic regions. Neighboring states experiencing large increases in child neglect during economic downturns may extend their collaborative efforts so they can develop strategies for improving services. Future research should explain the growth in child neglect with other variables aside from TANF caseloads.     

Connected for Development? Theory and evidence about the impact of Internet technologies on poverty alleviation

Based on the assumption that increased access to internet services boosts economic growth and improves the well‐being of the poor, governments in both developed and emerging regions are heavily investing in internet connectivity projects. This article reviews the existing evidence as to the impact of internet technologies on various development dimensions, and articulates the empirical evidence into an analytical framework that seeks to identify the micro‐linkages between internet adoption and poverty alleviation. The review suggests that the development pay‐offs of internet technologies are ambiguous due to two interrelated effects. First, because effective appropriation requires a range of skills as well as complementary investment in human capital and organizational changes. This tends to favour well‐educated workers and firms with more innovative capacity and access to finance. Second, because the positive effects of internet dissemination on market co‐ordination and political institutions grow exponentially with adoption levels. As a result, while the evidence indicates that advanced economies are reaping significant benefits from internet investments, the returns for less advanced economies, and in particular for the fight against poverty in these regions, remain uncertain.     

Double moving average–EWMA control chart for exponentially distributed quality

A control chart is an ever-popular tool for monitoring the production process. The early detection of a process shift, if any, is the desire of the quality control personnel. In this article, an effective alternative control charting procedure has been developed for the monitoring of exponentially distributed quality characteristic using the double moving average combined with EWMA statistic. The performance of the proposed control chart is examined for different combinations of the shift constant, the EWMA smoothing parameter, the moving average span, and the target in-control average run lengths. It has been observed that the proposed control chart is more efficient in the detection of process shifts as compared to control chart suggested by Khoo and Wang for the same purpose. The proposed control chart is illustrated for practical usage with the help of a synthetic and a real dataset.     

Statistical Analysis Of Mixture Vector Autoregressive Models

In this paper, we reconsider the mixture vector autoregressive model, which was proposed in the literature for modelling non‐linear time series. We complete and extend the stationarity conditions, derive a matrix formula in closed form for the autocovariance function of the process and prove a result on stable vector autoregressive moving‐average representations of mixture vector autoregressive models. For these results, we apply techniques related to a Markovian representation of vector autoregressive moving‐average processes. Furthermore, we analyse maximum likelihood estimation of model parameters by using the expectation–maximization algorithm and propose a new iterative algorithm for getting the maximum likelihood estimates. Finally, we study the model selection problem and testing procedures. Several examples, simulation experiments and an empirical application based on monthly financial returns illustrate the proposed procedures.     

An exponentially weighted moving average chart controlling false discovery rate

A new control chart is developed by using the exponentially weighted moving average (EWMA) statistics and a multiple testing procedure for controlling false discovery rate. The multiple testing procedure considers not only the current EWMA statistic, but also a given number of previous statistics at the same time. Numerical simulations are accomplished to evaluate the performance of the proposed control chart in terms of the average run length and the conditional expected delay. The results are compared with those of the existing control charts including the X-bar chart, EWMA, and cumulative sum control charts. Case studies with real data-sets are also presented.     

射孔完井有限元模型的建立及网格划分

介绍了射孔完井中二维和三维有限元热流模型的建立及网格划分的基本方法,用热流场模拟射孔完井渗流场,用同一种导热率材料来模拟井筒和孔眼,该材料导热率相对于地层模型导热率为无限大时,能模拟整个射孔完井渗流场。该二维和三维模型,能研究射孔深度、有无钻井污染和压实带情况下,孔眼内流体流速、压实带外边界渗流速度、渗流压力场、全井产量及产能比。并用APDL程序语言编写了二维和三维模型及网格划分的通用程序,为射孔完井优化设计及产能预测提供了实用的有限元网格模型,同时也为这方面的研究提供了简捷的方法。