A comparison of recent nonparametric methods for testing effects in two-by-two factorial designs

The two-way two-levels crossed factorial design is a commonly used design by practitioners at the exploratory phase of industrial experiments. The F-test in the usual linear model for analysis of variance (ANOVA) is a key instrument to assess the impact of each factor and of their interactions on the response variable. However, if assumptions such as normal distribution and homoscedasticity of errors are violated, the conventional wisdom is to resort to nonparametric tests. Nonparametric methods, rank-based as well as permutation, have been a subject of recent investigations to make them effective in testing the hypotheses of interest and to improve their performance in small sample situations. In this study, we assess the performances of some nonparametric methods and, more importantly, we compare their powers. Specifically, we examine three permutation methods (Constrained Synchronized Permutations, Unconstrained Synchronized Permutations and Wald-Type Permutation Test), a rank-based method (Aligned Rank Transform) and a parametric method (ANOVA-Type Test). In the simulations, we generate datasets with different configurations of distribution of errors, variance, factor's effect and number of replicates. The objective is to elicit practical advice and guides to practitioners regarding the sensitivity of the tests in the various configurations, the conditions under which some tests cannot be used, the tradeoff between power and type I error, and the bias of the power on one main factor analysis due to the presence of effect of the other factor. A dataset from an industrial engineering experiment for thermoformed packaging production is used to illustrate the application of the various methods of analysis, taking into account the power of the test suggested by the objective of the experiment.     

DS18B20在油气井场温度监控系统中的应用

油气井场温度监控系统属于井场重要的安全保护装置,此系统用单片机+串行智能传感器来组成,广泛使用了串行芯片。介绍了系统硬件流程图,以及温度传感器芯片DS18B20的工作流程,详细说明了获取温度传感器序列号的ROM操作命令、存储器操作命令。     

汽车侧围外板尾翼拉延成型工艺改善研究

为解决汽车侧围外板尾翼在拉延成型后出现起皱和开裂的问题，设计了3种造型方案.通过造型设计分析及Autoform模拟，对比3种方案，对原工艺进行整改和优化，得到了抬高造型台阶面的最优造型方案.该方案能改善进料速度、增加材料流动性，有效地消除开裂、起皱的缺陷，对同类和其他类似产品的冲压工艺设计具有参考意义.     

1981—2014年中国资本服务流量测算——基于截断正态退役分布和几何役龄效率剖面

通过梳理资本核算理论框架,结合中国实际情况测量了1981-2014年资本服务流量。资本分类、组合役龄效率-退役剖面计算、资本回报率确定和初始单位效率生产性资本存量估计等方面与既有研究有所不同。测量结果表明:按照1990年不变价格,各类资本服务流量呈增加趋势,其中无形资产服务流量前期较为波动;设备类服务流量增速最高;总资本服务增长率前期呈V型后期呈倒U型,与GDP增速变动不一致,整体来看前者高于后者;比较发现测量结果高于其它研究,差距先收敛后扩大。     

Minimally informative distributions with given rank correlation for use in uncertainty analysis

Minimum information bivariate distributions with uniform marginals and a specified rank correlation are studied in this paper. These distributions play an important role in a particular way of modeling dependent random variables which has been used in the computer code UNICORN for carrying out uncertainty analyses. It is shown that these minimum information distributions have a particular form which makes simulation of conditional distributions very simple. Approximations to the continuous distributions are discussed and explicit formulae are determined. Finally a relation is discussed to DAD theorems, and a numerical algorithm is given (which has geometric rate of covergence) for determining the minimum information distributions.     

美学研究之当下论域与理论前景

近年来,我国的美学研究蓬勃发展,美学基本原理探讨成效显著,中外美学史梳理有条不紊,部门美学研究异彩纷呈,流派美学研究乐此不疲。其主要特征有五:一是参与者众,成果五花八门;二是师承关系明显,排异性强;三是教材各异,令人无所适从;四是思辨者多,实验取证者少,归纳总结者多,创新者少;五是学位论文俨然成为新见主产地。研究方法主要有哲学思辨法、心理还原法以及语义分析、经验主义、社会学、历史学、系统论等。不足之处即为缺乏理论创新,鲜有大师级人物出现,故此未来之研究应以创新为第一要务,力求把深奥难懂的美学理论阐发得通俗易懂。     

水平井分段多簇压裂缝间干扰研究

水平井分段多簇压裂在现场得到了广泛运用，其压裂过程中普遍存在缝间干扰现象。缝间干扰有助于形成复 杂裂缝网络以提高储层导流能力，但是也会导致起裂困难，甚至形成砂堵。因此有必要对分段多簇压裂的缝间干扰问 题进行研究。对此，基于弹性力学建立了分析多簇裂缝诱导应力的数学模型，从起裂压力、裂缝宽度、簇间距等多方面 研究了缝间干扰对水平井分段多簇压裂施工的影响。模拟结果显示，诱导应力会导致起裂压力升高、裂缝变窄，严重 时将造成压裂施工失败。通过进行分析，给出了起裂过程及延伸过程中缝间干扰的影响关系。分析认为，利用缝间干 扰提高改造体积时应当控制簇间距防止对压裂施工造成负面影响。研究结论对优化水平井分段多簇压裂设计具有指 导意义。     

从城市崇拜看阎连科的小说创作

阎连科出生在贫困的乡村,由于童年和少年时期的缺失性体验而产生一种向往城市的心理。这种心理在他的小说中体现为贫瘠土地上的青年农民拼命逃离土地、渴望进入城市的迫切心情。他的小说可以让人感受到主人公在逃离土地之路上挣扎的痛苦心声,同时也可体味到作者希冀精神上回归土地的殷切心情。     

Incomplete categorical data analysis: a bayesian perspective

In this paper the Bayesian analysis of incomplete categorical data under informative general censoring proposed by Paulino and Pereira (1995) is revisited. That analysis is based on Dirichlet priors and can be applied to any missing data pattern. However, the known properties of the posterior distributions are scarce and therefore severe limitations to the posterior computations remain. Here is shown how a Monte Carlo simulation approach based on an alternative parameterisation can be used to overcome the former computational difficulties. The proposed simulation approach makes available the approximate estimation of general parametric functions and can be implemented in a very straightforward way.