Independence and sphericity tests for the residuals of space-time arma models

The mechanics of the procedure for building space-time autoregressive moving average (STARMA) models is dependent upon the form of G, the variance-covariance matrix of the underlying errors.This paper presents large sample tests of the hypotheses that G is diagonal and that G equals o² I. Tables of the critical values for these tests are constructed     

ASSESSING FAMILIAL AGGREGATION WITH AN ORDINAL RESPONSE

A latent variable model is considered for the analysis of twin data with an ordinal response. The underlying latent multivariate normally distributed variable is expressed in terms of genetic and environmental effects, and the variance components associated with these effects are estimated. We illustrate this approach with analysis of the NHLBI Twin Study. Model assessment is ascertained by proposing a goodness-of-fit test for ordered categorical data. Extensions of this approach for the investigation of how genetic effects vary over time are discussed.     

Applications of Marshall–Olkin Fréchet Distribution

In this article, we consider the applications of Marshall–Olkin Fréchet distribution. The reliability of a system when both stress and strength follows the new distribution is discussed and related characteristics are computed for simulated data. The model is applied to a real data set on failure times of air-conditioning systems in jet planes and reliability is estimated. We also develop acceptance sampling plan for the acceptance of a lot whose lifetime follows this distribution. Four different autoregressive time series models of order 1 are developed with minification structure as well as max-min structure having these stationary marginal distributions. Some properties of the models are also established.     

一个不等式的推广

推广了一个不等式，得到下列两个不等式，其中B＞A＞0，a＞1和γ≠0为实数，n和k为正整数。并给出了一个猜测。     

基于特定数学模型的语义抽取研究

进入知识社会,大量芜杂的信息使得读者陷入了尴尬的境地,笔者针对此种情况,从数学的角度来进行特定模型的语义抽取研究,通过相似值的计算、过滤及最大墒值的自动提取等环节来为用户自动抽取简洁的信息需求内容,并设计出一套科学合理的计算模式,以期对相关领域的理论研究及实践发展有所贡献.     

On Determining the BMD from Multiple Outcomes in Developmental Toxicity Studies when One Outcome is Intentionally Missing

Public health concerns over the occurrence of developmental abnormalities that can occur as a result of prenatal exposure to drugs, chemicals, and other environmental factors has led to a number of developmental toxicity studies and the use of the benchmark dose (BMD) for risk assessment. To characterize risk from multiple sources, more recent analytic methods involve a joint modeling approach, accounting for multiple dichotomous and continuous outcomes. For some continuous outcomes, evaluating all subjects may not be feasible, and only a subset may be evaluated due to limited resources. The subset can be selected according to a prespecified probability model and the unobserved data can be viewed as intentionally missing in the sense that subset selection results in missingness that is experimentally planned. We describe a subset selection model that allows for sampling pups with malformations and healthy pups at different rates, and includes the well‐known simple random sample (SRS) as a special case. We were interested in understanding how sampling rates that are selected beforehand influence the precision of the BMD. Using simulations we show how improvements over the SRS can be obtained by oversampling malformations, and how some sampling rates can yield precision that is substantially worse than the SRS. We also illustrate the potential for cost saving with oversampling. Simulations are based on a joint mixed effects model, and to account for subset selection, use of case weights to obtain valid dose‐response estimates.     

巴特鲁斯、蒙田、笛卡尔和近代古典理性概念的形成

在欧洲思想史上,近代古典理性概念是如何形成的问题是理解近代哲学革命的关键。在中世纪晚期,占主导地位的是亚里士多德和阿奎那的审慎理性概念,经过巴特鲁斯主义和马基雅维里主义的发挥,最后被蒙田推向极端——怀疑理性。为了克服这种怀疑论,笛卡尔在伽利略新科学的基础上提出了以普遍数学为导向的数学理性概念,不仅为近代自然科学革命奠定了形而上学的基础,而且标志着近代古典理性概念正式成型。     

Evaluation of Response Scenarios to Potential Polio Outbreaks Using Mathematical Models

Appropriate response to polio outbreaks represents an important prerequisite for achieving and maintaining global polio eradication. We use an existing dynamic disease transmission model to evaluate the impact of different aspects of immunization campaigns in response to polio outbreaks occurring in previously polio-free areas. This analysis yields several important insights about response strategies. We find that delay in response represents a crucial risk factor for occurrence of large outbreaks and we characterize the tradeoffs associated with delaying the initial response to achieve better population coverage. We also demonstrate that controlling most potential outbreaks will likely require at least three immunization rounds, although the impact of the optimal interval between rounds varies. Finally, long after oral poliovirus vaccine cessation the choice of target age groups during a response represents an important consideration.     

浅谈“概率论与数理统计”教学

概率论与数理统计是一门应用性很强的课程,要提高其教学质量,培养创新人才,必须做到变革现有考试制度,采用笔试、课后作业和课程论文相结合的方式;变革现有教学内容,压缩概率论知识,增加统计内容,特别是多元统计,结合计算机强化统计软件应用;变革现有教学方法,注重原型启发式教学,强化理论联系实际。     

蓖麻毒素A链的结构模建

蓖麻毒素A链（RTA）有抑制蛋白质合成的功能，可与单克隆抗体交联制备免疫毒素，用以治疗肿瘤顽症，但其免疫原性较强．天然RTA分子量大，不易渗透到肿瘤组织内部．因此，利用同源模建的方法对RTA分子进行改造，构建RTA突变体（MRTA），以改善天然RTA缺陷成为必要．近年来，生物信息学飞速发展，各种蛋白质库日益完善，计算机技术日趋成熟以及各种软件的开发，为分子结构模建提供了可能．