A study of BIB designs through support matrices

This paper deals with the existence and nonexistence of BIB designs with repeated blocks. The approach is an algebraic one. The concept of a support matrix is introduced and some of its basic properties are noted. Some basic examples of support matrices are given when the block size is 3. The connection between full column rank proper support matrices and irreducible designs is explored and some examples of such matrices are given.     

AN ALGORITHMIC APPROACH TO BAYESIAN LINEAR MODEL CALCULATIONS

A framework is described for organizing and understanding the computations necessary to obtain the posterior mean of a vector of linear effects in a normal linear model, conditional on the parameters that determine covariance structure. The approach has two major uses; firstly, as a pedagogical tool in the derivation of formulae, and secondly, as a practical tool for developing computational strategies without needing complicated matrix formulae that are often unwieldy in complex hierarchical models. The proposed technique is based upon symbolic application of the sweep operator SWP to an appropriate tableau of means and covariances. The method is illustrated with standard linear model specifications, including the so-called mixed model, with both fixed and random effects.     

二次型与(半)稳定矩阵的判定

对二次型与（半）稳定矩阵之间的相互关系进行了讨论，得到了二者之间的相互判定方法，且利用二次型的不同配方法得到判定（半）稳定矩阵的一些条件     

开放微带不连续电路的三端口网络描述

给出了开放微带不连续电路的三端口网络描述。将微带电路向空间的辐射作为一个端口来处理，成功地消除了由于忽略电路的空间辐射效应引入的电路数字模拟误差。利用时域有限差分法（ＦＤＴＤ）一次运算就可得出三端口网络的Ｓ参数矩阵的各元素，而无需任何预处理，大大地节省了ＣＰＵ时间。实际计算与已发表的数据吻合得很好，表明文中给出的三端口定义是合理有效的。此三端口微带电路的定义可容易地推广到其他非屏蔽传输线电路的分析，可广泛用于电磁兼容分析、微带天线及其他开放传输线电路的ＣＡＤ技术中。     

Minkowski 不等式的进一步拓广

将正定（实对称）阵的Ｍｉｎｋｏｗｓｋｉ不等式拓广到更一般的一类矩阵，推广和改进了有关文献的结果．     

Statistical methodology for assessing homology of intronic regions of genes

We consider the problem of statistically evaluating the similarity of DNA intronic regions of genes. Present algorithms are based on matching a sequence of interest with known DNA sequences in a gene bank and are designed primarily to assess homology among exonic regions of genes. Most research focuses on exonic regions because they have a clear biological significance, coding for proteins, and therefore tend to be more conserved in evolution than intronic regions. To investigate whether the intronic features of genes whose expression is highly sensitive to environmental perturbations differ from genes that have a more constant expression, a collection of oncogenes, tumor suppressor genes, and nonregulatory genes involved in energy metabolism are compared. An analysis of the features of these genes' intronic regions result in clustering by regulatory group. In addition, Billingsley's test for Markov structure (1961) suggests that 67% of the intronic regions in this collection of genes show evidence of nonrandom structure, indicating the possibility of a biological function for these regions. The result of Billingsley's test for homology is used as input to a clustering algorithm. The biological significance of this methodology lies in the identification of groups based on the intronic regions from genes of unknown function. With the advent of rapid sequencing techniques, there is a great need for statistical techniques to help identify the purpose of poorly understood portions of genes. These methods can be utilized to assess the functional group to which such a gene might possibly belong.     

非负矩阵谱半径的估计

对非负矩阵谱半径的界值给出了一个新的估计.并引进某些自由参数,使谱半径得到了更一般的结果。     

有关P_B~⊥P_A、P_A~⊥P_B的矩阵等式和秩等式

在M=(A B)中,令A1=P⊥BPA,B1=P⊥APB,利用投影算子理论和矩阵秩方法可以得到关于A1,B1的一些矩阵等式和秩等式.     

N80 钢/SiO2 基涂层/油井水泥石的界面特征研究

为了提高固井一界面的胶结强度,采用热化学反应法在N80 钢制套管钢基体上制备SiO2 基陶瓷涂层作为套管和水泥石之间的过渡层。通过X 射线衍射结构分析、扫描电子显微镜和体视显微镜形貌观察以及划痕仪涂层结合力测试,研究了N80 钢/SiO2 基涂层/油井水泥石的界面微观结构特征和结合行为。结果表明,陶瓷涂层内部和陶瓷涂层/水泥石界面分别产生了新相MgAl2O4 和Ca54MgAl2Si16O90;陶瓷涂层与钢基体结合力的临界载荷在40 N 左右,陶瓷涂层的制备起到了提高套管与水泥石结合强度的作用。     

Tempered Regrets Under Total Ignorance

Several decision rules, including the minimax regret rule, have been posited to suggest optimizing strategies for an individual when neither objective nor subjective probabilities can be associated to the various states of the world. These all share the shortcoming of focusing only on extreme outcomes. This paper suggests an alternative approach of tempered regrets which may more closely replicate the decision process of individuals in those situations in which avoiding the worst outcome tempers the loss from not achieving the best outcome. The assumption of total ignorance of the probabilities associated with the various states is maintained. Applications and illustrations from standard neoclassical theory are discussed.