车行横洞施工对隧道主洞变形的影响

针对隧道车行横洞施工对主洞结构产生影响，以运城 灵宝高速公路中条山隧道工程为依托，采用现场试验和三维有限元仿真的方法，对车行横洞施工阶段主洞的变形规律进行了研究。研究结果表明：车行横洞施工对主洞的影响，在时间上主要表现在交叉口初支拆除和横洞的第1个开挖步，随着横洞开挖深度的增加，主洞结构的变形逐步趋于稳定;车行横洞施工对隧道主洞围岩变形影响主要表现为主洞拱顶下沉量增加和开挖侧拱脚水平位移减小，主洞未开挖侧拱脚水平位移影响不大。     

Likelihood ratio test for simultaneous testing of the mean and the variance of a normal distribution

In this paper, we consider the simultaneous testing of the mean and the variance of a normal distribution. The exact distribution of the likelihood ratio test statistic is obtained, which is not available in the literature. The critical points of the exact test are reported. We also consider some of the other exact and asymptotic tests. The powers of these tests are compared using the Monte Carlo simulations.     

Randomized confidence intervals of a parameter for a family of discrete exponential type distributions

For a family of one-parameter discrete exponential type distributions, the higher order approximation of randomized confidence intervals derived from the optimum test is discussed. Indeed, it is shown that they can be asymptotically constructed by means of the Edgeworth expansion. The usefulness is seen from the numerical results in the case of Poisson and binomial distributions.     

Interaction Between Autocorrelation and Conditional Heteroscedasticity: A Random-Coefficient Approach

In applied econometrics, we tend to tackle specification problems one at a time rather than considering them jointly. This has serious consequences for statistical inference. One example of this is considering autocorrelation and autoregressive conditional heteroscedasticity (ARCH) separately. In this article we consider a linear regression model with random coefficient autoregressive disturbances that provides a convenient framework to analyze autocorrelation and ARCH simultaneously. Our stationarity conditions and testing results reveal the strong interaction between ARCH and autocorrelation. An empirical example of testing the unbiasedness of experts' expectations of inflation demonstrates that neglecting conditional heteroscedasticity or misspecifying the autocorrelation structure might result in unreliable inference.     

Small-Sample Corrections for Score Tests in Birnbaum–Saunders Regressions

In this article, we deal with the issue of performing accurate small-sample inference in the Birnbaum–Saunders regression model, which can be useful for modeling lifetime or reliability data. We derive a Bartlett-type correction for the score test and numerically compare the corrected test with the usual score test and some other competitors.     

大学学业考试的公平性及影响研究--来自学生的反馈

本研究采用问卷形式调查学生对大学学业考试公平性及其影响的看法。结果显示,大学学业考试存在一些较为严重的问题,如对学生知识及能力的考查不够,且部分命题教师在考前透露考试内容;一些监考老师责任心不强,态度松懈,致使舞弊现象发生;阅卷过程不太规范等。这些考试不公平现象在一定程度上对学生的学习、生活及考试制度的良性发展产生了较为严重的影响。因而,有必要对教师进行培训,让他们对考试公平性有更全面的认识,从而在实践中采取更有效的措施提升考试公平性。     

基于城市经济空间联系的江西省区域发展研究

针对宽高比为5的矩形断面梁进行了节段模型测压风洞试验,研究了矩形断面梁的气动力特性随风攻角的变化规律。研究结果表明：在0°~6°的风攻角范围内,风攻角对斯托罗哈数的影响很小;不同风攻角下的驰振力系数均大于0;与上表面中间位置的测点相比,上表面边缘位置测点的压力与升力和扭矩的相关性更强;上表面边缘位置测点的压力与升力和扭矩的相关性对风攻角的变化不敏感;随着风攻角的增大,上表面中间位置测点的压力与升力和扭矩的相关性显著增强。     

我国优质高等教育资源分布格局的百年演变———基于民国以来的历史考察

自民国以来,我国优质高等教育资源经历了国立大学、重点大学、“211工程”大学和“985工程”大学三次变化。尽管我国优质高等教育资源不断增加,但分布不均衡是其显著特征,具体表现为省际差异和区域不均衡。从省际分布来看,优质高等教育资源经历了从相对均衡到不均衡的转变;从区域分布来看,东部优质高等教育资源无论是在数量上还是在质量上都强于中西部,而优质高等教育资源“南强北弱”的格局则逐渐演变为“北强南弱”。我国优质高等教育资源的分布与政权中心的变迁和区域整体经济发展程度关系密切,但与各省、市、自治区经济发展程度并非呈简单的正相关。因此,促进各省、市、自治区经济发展实力的提升与政府宏观调控相结合是扭转优质高等教育资源分布失衡格局的应有逻辑。     

Generalisation of Mood's Test to Factorial Designs to Detect Heterogeneity of Variances

Mood's test, which is a relatively old test (and the oldest non‐parametric test among those tests in its class) for determining heterogeneity of variance, is still being widely used in different areas such as biometry, biostatistics and medicine. Although it is a popular test, it is not suitable for use on a two‐way factorial design. In this paper, Mood's test is generalised to the 2 × 2 factorial design setting and its performance is compared with that of Klotz's test. The power and robustness of these tests are examined in detail by means of a simulation study with 10,000 replications. Based on the simulation results, the generalised Mood's and Klotz's tests can especially be recommended in settings in which the parent distribution is symmetric. As an example application we analyse data from a multi‐factor agricultural system that involves chilli peppers, nematodes and yellow nutsedge. This example dataset suggests that the performance of the generalised Mood test is in agreement with that of the generalised Klotz's test.     

Validation tests for semi-parametric models

Tests are proposed for validation of the hypothesis that a partial linear regression model adequately describes the structure of a given data set. The test statistics are formulated following the approach of Fourier-type conditional expectations first suggested by Bierens [Consistent model specification tests. J Econometr. 1982;20:105–134]. The proposed procedures are computationally convenient, and under fairly mild conditions lead to consistent tests. Corresponding bootstrap versions are compared with alternative procedures for a wide selection of different estimators of the underlying partial linear model.