A-Optimal Block Designs with Additional Singly Replicated Treatments

Block designs to which have been added a number of singly-replicated treatments, known as secondary treatments, are particularly useful for experiments where only small amounts of material are available for some treatments, for example new plant varieties. The designs are of particular use in the microarray situation. Such designs are known as 'augmented designs'. This paper obtains the properties of these designs and shows that, with an equal number of secondary treatments in each block, the A-optimal design is obtained by using the A-optimal design for the original block design. It develops formulae for the variance of treatment comparisons, for both the primary and the secondary treatments. A number of examples are used to illustrate the results.     

双块式轨枕挡肩裂纹原因分析及控制

挡肩裂纹是双块式轨枕预制的一项严重质量问题，将直接导致轨枕报废，若控制不到位，将给企业造成严重经济损失。以新建贵阳至广州铁路广宁轨枕预制场双块式轨枕施工为例，从脱模机构、混凝土配合比、混凝土养护等方面分析了挡肩裂纹出现的原因，并制定出针对性措施，为以后双块式轨枕的质量控制提供参考和借鉴。     

从《几何原本》的刊刻到"雪耻"的数学世家——兼论曾氏家族对近代中国科学技术发展的贡献

曾国藩曾以不识天文算学为"一耻",并寄望于儿辈为其"雪耻",并招数学家李善兰入幕府,资助刊刻<几何原本>中译本,并由此培养了儿孙辈对科学技术的爱好和钻研,次子纪鸿四代一脉相承为"数学世家".     

用改进单纯形优化法设计油田阻垢剂组成

使用单一药剂往往难以达到满意的阻垢效果，通常采用几种单药剂进行复配，复配剂在油田阻垢性能上有明显的协同增效作用。运用改进单纯形优化法，以我国某海上油田注入水和地层水矿化度为例，选用聚丙烯酸(PAA)、聚天冬胺酸(PASP)、乙二胺四亚甲基磷酸（EDTMP）和柠檬酸（CA）为单纯形因素，以平均阻垢率为单纯形响应值，进行药剂复配优化设计。经12次实验，找到了最优配方，PAA∶PASP∶EDTMP∶CA=59.4∶15.7∶4.6∶20.3。实验过程表明，该方法在寻优过程中具有简单、准确以及实验次数少的优点。     

基于保险交易的静态最优区块链模型研究

保险业的经营特征与区块链技术存在天然契合性,本文通过分析基于区块链技术的保险交易流程,构建了基于保险交易的静态最优区块链模型,得到了保单区块存储员的最优区块存储能力、区块存储成本以及限制区块链违约分叉的约束条件。进一步以我国车险市场的经营数据为例进行数值模拟,得到区块规模、平均记录时间、平均交易费用等指标的最优结果。通过比较静态分析发现,保险交易数量、保单区块存储员人数、区块存储时间等增加以及风险损失率的降低均会导致区块规模增加以及保险交易记录时间和保险交易费用的减少,而外部冲击的增加会导致区块规模的增加以及保险交易记录时间减少,但对保险交易费用的影响取决于因外部冲击增加而产生的交费激励增加和区块规模受限而导致的交费激励减少之间的平衡。基于研究结果,本文在保险科技协同、区块链系统设计和具体场景实践等方面提出了政策建议,同时也指出了一些有待解决的现实问题。     

我国大宗交易法律制度的应然建构

在现实股票交易中,一些机构投资者利用大宗交易市场和竞价市场的漏洞,联合坐庄套利,严重损害投资者的利益。应当从大宗交易市场参与者、大宗交易市场行为、信息披露与监管、大宗交易市场信用交易等方面建构我国大宗交易法律制度。     

分组密码算法认证运算模式的注记及可证安全性

对分组密码算法CCM、CMAC加密模式进行描述,用可证安全性理论对它们进行相关研究和证明,并对各种证明情况在不同通信环境下的使用作出说明。针对认证工作模式用流程图的方式进行描述,同时证明了所有标准化的运算模式对于不同的使用环境是安全的。所研究内容对于2007年7月公布的GCM模式仍然适用,而且对于新的运算模式设计,可证安全性仍然是一个必要的环节。     

手提式砂轮机在车床上磨削工件的工艺研究

许多中小型企业由于缺少磨床设备,致使一些需要磨削加工的工件无法进行加工。利用手提式砂轮机装配一简单卡箍夹具,组合成一个简易磨具,装夹在车床上,选择合适的砂轮,就可实现磨削加工。     

On Block Ordering of Variables in Graphical Modelling

Abstract.  In graphical modelling, the existence of substantive background knowledge on block ordering of variables is used to perform structural learning within the family of chain graphs (CGs) in which every block corresponds to an undirected graph and edges joining vertices in different blocks are directed in accordance with the ordering. We show that this practice may lead to an inappropriate restriction of the search space and introduce the concept of labelled block ordering B corresponding to a family of B - consistent CGs in which every block may be either an undirected graph or a directed acyclic graph or, more generally, a CG. In this way we provide a flexible tool for specifying subsets of chain graphs, and we observe that the most relevant subsets of CGs considered in the literature are families of B -consistent CGs for the appropriate choice of B . Structural learning within a family of B -consistent CGs requires to deal with Markov equivalence. We provide a graphical characterization of equivalence classes of B -consistent CGs, namely the B - essential graphs , as well as a procedure to construct the B -essential graph for any given equivalence class of B -consistent chain graphs. Both largest CGs and essential graphs turn out to be special cases of B -essential graphs.