Optimal block designs for triallel cross experiments

Optimal block designs for a certain type of triallel cross experiments are investigated. Nested balanced block designs are introduced and it is shown how these designs give rise to optimal designs for triallel crosses. Several .series of nested balanced block designs, leading to optimal designs for triallel crosses are reported.     

Robustness of Optimal Chemical Balance Weighing Designs for Estimation of Total Weight

The subject of our study is the chemical balance weighing design in which the errors are correlated and have equal variances. A lower bound for the variance of estimated total weight is obtained and the necessary and sufficient conditions for the attainability of this lower bound are given. Some designs for which the lower bound is attainable are considered.     

A-Optimal Spring Balance Weighing Designs Under Some Conditions

In this article, the estimation problem of individual weights of objects in spring balance weighing design using the criterion of A-optimality is discussed. It is assumed that the measurement errors have different variances. The lowest bound of the trace of the dispersion matrix is obtained and the conditions when this lowest bound is achieved are given. A new construction method of an A-optimal design is presented.     

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。     

Balanced Treatment incomplete block (BTIB) designs for comparing treatments with a control: minimal complete sets of generator designs for k = 3, p = 3(1)10

Bechhofer and Tamhane (1981) proposed a new class of incomplete block designs called BTIB designs for comparing p ≥ 2 test treatments with a control treatment in blocks of equal size k < p + 1. All BTIB designs for given (p,k) can be constructed by forming unions of replications of a set of elementary BTIB designs called generator designs for that (p,k). In general, there are many generator designs for given (p,k) but only a small subset (called the minimal complete set) of these suffices to obtain all admissible BTIB designs (except possibly any equivalent ones). Determination of the minimal complete set of generator designs for given (p,k) was stated as an open problem in Bechhofer and Tamhane (1981). In this paper we solve this problem for k = 3. More specifically, we give the minimal complete sets of generator designs for k = 3, p = 3(1)10; the relevant proofs are given only for the cases p = 3(1)6. Some additional combinatorial results concerning BTIB designs are also given.     

On properties of efficiency-balanced designs

We consider a class of efficiency-balanced block designs which are design patterns for the analytical simplification of statistical analysis. This paper consists of eight sections which investigate various problems (such as, bounds on parameters, characterizations, existence and nonexistence, and dual designs) for efficiency-balanced block designs.     

Some adjusted orthogonal,variance balanced,multidimensional block designs

A multidimensional block design (MBD) is an experimental design with d > 1 blocking criteria geometrically represented as a d-dimensional lattice with treatment varieties assigned to some or all nodes of the lattice. Intrablock analysis of variance tables for some special classes of two- and three-dimensional block designs with some empty nodes are given. Design plans and efficiencies for 31 two-dimensional designs, each universally optimal in defined classes of designs, and 7 three-dimensional designs, each nearly optimal in defined classes of designs, are listed in the appendices. A need for such designs is apparent when the blocking criteria are implemented successively and empty nodes do not represent wasted experimental units.     

Partially balanced incomplete block designs with two associate classes

We provide constructions of cyclic 2-class PBIBD's using cyclotomy in finite fields. Our results give theoretical explanations of the two sporadic examples given by Agrawal (1987).     

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。     

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。