Inferences on the Means of Two Log-Normal Distributions: A Computational Approach Test

In this article, we propose a novel approach for testing the equality of two log-normal populations using a computational approach test (CAT) that does not require explicit knowledge of the sampling distribution of the test statistic. Simulation studies demonstrate that the proposed approach can perform hypothesis testing with satisfying actual size even at small sample sizes. Overall, it is superior to other existing methods. Also, a CAT is proposed for testing about reliability of two log-normal populations when the means are the same. Simulations show that the actual size of this new approach is close to nominal level and better than the score test. At the end, the proposed methods are illustrated using two examples.     

Testing equality of two normal covariance matrices with monotone missing data

Abstract

The problem of testing equality of two multivariate normal covariance matrices is considered. Assuming that the incomplete data are of monotone pattern, a quantity similar to the Likelihood Ratio Test Statistic is proposed. A satisfactory approximation to the distribution of the quantity is derived. Hypothesis testing based on the approximate distribution is outlined. The merits of the test are investigated using Monte Carlo simulation. Monte Carlo studies indicate that the test is very satisfactory even for moderately small samples. The proposed methods are illustrated using an example.     

疲劳裂纹扩展试验裂纹图像采集系统

针对目前金属疲劳裂纹扩展检测方法存在效率低、操作繁琐、精度不高，不能实现实时性等缺点，文章提出了基 于机器视觉的裂纹检测方法。根据金属疲劳裂纹扩展试验过程中裂纹图像的采集要求，设计了摄像头位置可自动调整 的疲劳裂纹图像采集系统，包括摄像头安装运动装置，裂纹图像采集装置以及摄像头运动控制系统。图像采集装置由高 分辨率黑白面阵CCD摄像头、光学镜头，光源照明装置和图像采集卡组成，前3者安装在摄像头支架上，与摄像头运动 装置相连。摄像头运动装置中的X，Y，，Z轴运动机构由步进电机带动滚珠导轨机构。在基于ARM技术的运动控制系统 的控制下摄像头可沿X，Y，，Z轴作高精度直线运动，实现和试件之间精确位置的调整。实验结果表明，所设计的系统可 采集到疲劳裂纹扩展试验过程中高清晰度、高分辨率的试件裂纹图像，满足下一步裂绞尺寸计算的要求；摄像头运动定 位精度可达到0. 02 mm，满足精确的系统聚焦、位置调整、跟踪采集的要求。     

司法附属行政语境下的中国古代法官地位

“司法附属行政”是中国古代司法的一个重要特征。在这一背景下，中国古代法官地位就呈现出鲜明的附属性特征，这种特征同样体现在法院的地位和司法权的地位上，这也导致中国古代法官没有专门的职业保障制度，而这一切都深深地镶嵌在当时的人治大背景之中。通过与现代法官地位的比较，可以更加深切地感受到古今法官地位以至整个司法状况的巨大差异。中国现代法官地位在独立性方面相对于古代法官有了巨大改善，但仍然不尽如人意，还需要在今后的司法改革中进行反思和重点关注。     

清代冕宁司法档案中的“夷兵”及其功能考察

清代冕宁县作为多民族杂居的地区，雍正年间改土归流后，国家治理开始深入基层社会，为了适应当地民族社会管理的特别需要，当地形成了一种特殊的制度——夷兵换班制。“夷兵换班制”是通过招募当地“夷民”到流官衙署中充当“夷兵”，作为地方流官处理涉及少数民族内部事务的辅助人员，保证国家在处理当地少数民族民政、治安、司法等事务时有熟悉当地“夷俗”的衙吏。由于“夷兵”实行定期轮换，所以称为“夷兵换班制”。“夷兵换班制”的核心是“夷兵”，“夷兵”从职能上看，最初是作为地方治安保安人员，但在现实中往往成为流官和夷民之间在民政、治安、司法事务管理中的中介，具有沟通官方与民间信息、促进国家法与民族习惯融合与互动、弥补外来官吏地方民族事务管理能力不足等功能。总之，“夷兵换班制”是清代地方流官衙署在西南地区治理时针对特定地区设置的一种变通制度，这种制度对于国家在少数民族地区基层社会的治理发挥着十分重要的积极作用。     

Random effects regression mixtures for analyzing infant habituation

Random effects regression mixture models are a way to classify longitudinal data (or trajectories) having possibly varying lengths. The mixture structure of the traditional random effects regression mixture model arises through the distribution of the random regression coefficients, which is assumed to be a mixture of multivariate normals. An extension of this standard model is presented that accounts for various levels of heterogeneity among the trajectories, depending on their assumed error structure. A standard likelihood ratio test is presented for testing this error structure assumption. Full details of an expectation-conditional maximization algorithm for maximum likelihood estimation are also presented. This model is used to analyze data from an infant habituation experiment, where it is desirable to assess whether infants comprise different populations in terms of their habituation time.     

Tests for time series of counts based on the probability-generating function

We propose testing procedures for the hypothesis that a given set of discrete observations may be formulated as a particular time series of counts with a specific conditional law. The new test statistics incorporate the empirical probability-generating function computed from the observations. Special emphasis is given to the popular models of integer autoregression and Poisson autoregression. The asymptotic properties of the proposed test statistics are studied under the null hypothesis as well as under alternatives. A Monte Carlo power study on bootstrap versions of the new methods is included as well as real-data examples.     

Inferences for a Partially Varying Coefficient Model With Endogenous Regressors

In this article, we propose a new class of semiparametric instrumental variable models with partially varying coefficients, in which the structural function has a partially linear form and the impact of endogenous structural variables can vary over different levels of some exogenous variables. We propose a three-step estimation procedure to estimate both functional and constant coefficients. The consistency and asymptotic normality of these proposed estimators are established. Moreover, a generalized F-test is developed to test whether the functional coefficients are of particular parametric forms with some underlying economic intuitions, and furthermore, the limiting distribution of the proposed generalized F-test statistic under the null hypothesis is established. Finally, we illustrate the finite sample performance of our approach with simulations and two real data examples in economics.     

司法会计鉴定审计刍议

近年来 ,随着国家经济建设迅速发展以及市场经济的进一步深化 ,随之而来的经济案件成为不可避免 ,司法机关在处理经济案件时 ,需要案件当事人双方提供真实的依据 ,以便公正断案。证据的真伪 ,需要有关专业技术人员来鉴定 ,而中国注册会计师为此项鉴定工作起到了很重要作用 ,会计师事务所的“司法会计鉴定审计”便应运而生。     

GMM tests for the Katz family of distributions

Generalized method of moments (GMM) is used to develop tests for discriminating discrete distributions among the two-parameter family of Katz distributions. Relationships involving moments are exploited to obtain identifying and over-identifying restrictions. The asymptotic relative efficiencies of tests based on GMM are analyzed using the local power approach and the approximate Bahadur efficiency. The paper also gives results of Monte Carlo experiments designed to check the validity of the theoretical findings and to shed light on the small sample properties of the proposed tests. Extensions of the results to compound Poisson alternative hypotheses are discussed.