Computing optimal adjustment schemes for the general tool-wear problem

An important problem in process adjustment using feedback is how often to sample the process and when and by how much to apply an adjustment. Minimum cost feedback schemes based on simple, but practically interesting, models for disturbances and dynamics have been discussed in several particular cases. The more general situation in which there may be measurement and adjustment errors, deterministic process drift, and costs of taking an observation, of making an adjustment, and of being off target, is considered in this article. Assuming all these costs to be known, a numerical method to minimize the overall expected cost is presented. This numerical method provides the optimal sampling interval, action limits, and amount of adjustment; and the resulting average adjustment interval, mean squared deviation from target, and minimum overall expected cost. When the costs of taking an observation, of making an adjustment, and of being off target are not known, the method can be used to choose a particular scheme by judging the advantages and disadvantages of alternative options considering the mean squared deviation they produce, the frequency with which they require observations to be made, and the resulting overall length of time between adjustments. Computer codes that perform the required computations are provided in the appendices and applied to find optimal adjustment schemes in three real examples of application.     

The mad estimator: when is it non-linear? applications to two-way design models

The mean absolute deviation (MAD) estimator has recently received a great deal of attention as applied to full-rank linear regression models. This paper provides a necessary and sufficient condition for the MAD estimator to be a non-linear estimator, in which case conditions for the variance of the MAD estimator to be larger or smaller than those for OLS are, in general, unknown. The non-linearity of the MAD estimator is examined for several two-way designs; in particular (1) randomized block design (2) two-way nested design (3) two-way classification with interaction and (4) partially balanced incomplete block design     

Flexible regression modeling

The author proposes a new method for flexible regression modeling of multi‐dimensional data, where the regression function is approximated by a linear combination of logistic basis functions. The method is adaptive, selecting simple or more complex models as appropriate. The number, location, and (to some extent) shape of the basis functions are automatically determined from the data. The method is also affine invariant, so accuracy of the fit is not affected by rotation or scaling of the covariates. Squared error and absolute error criteria are both available for estimation. The latter provides a robust estimator of the conditional median function. Computation is relatively fast, particularly for large data sets, so the method is well suited for data mining applications.     

解析脑筋急转弯中的认知语境工作机制

交际过程实际是人们借助语境对交际信息的认知过程.而脑筋急转弯总是传递偏离双方共有的认知语境的信息,从而迭到特殊的交际效果.文章尝试从认知语境角度来探讨脑筋急转弯的交际效果,在经过测试后总结出了脑筋急转弯中的认知语境工作的机制并归纳出语境偏离的几种情况.     

社会浮躁现象发生的原因及其遏制对策

从文化冲击、人性趋向、认知偏差、个人主义化与安全方面分析社会浮躁成因。本文认为,应从重新定位政府职能、以未来作为思考基点增强变革能力、抑制人性不良趋向加强舆论监督、矫正偏差等方面预防和遏制浮躁,使社会稳定发展。     

革命立场与女性意识的较量--读《一九三○年春上海》(之二)和《夜》

在丁玲的短篇小说<一九三○年春上海>(之二)和<夜>中,作家的创作意图与作品的客观效果发生了背离其女性意识比革命立场更为引人注目;小说的艺术重心在女性意识,丁玲思想中深植的女性意识,其创作方法上的矛盾,以及社会革命与女性命运的不一致,是导致这一背离的几个原因.     

A tolerance interval approach for assessment of agreement in method comparison studies with repeated measurements

This paper generalizes the tolerance interval approach for assessing agreement between two methods of continuous measurement for repeated measurement data—a common scenario in applications. The repeated measurements may be longitudinal or they may be replicates of the same underlying measurement. Our approach is to first model the data using a mixed model and then construct a relevant asymptotic tolerance interval (or band) for the distribution of appropriately defined differences. We present the methodology in the general context of a mixed model that can incorporate covariates, heteroscedasticity and serial correlation in the errors. Simulation for the no-covariate case shows good small-sample performance of the proposed methodology. For the longitudinal data, we also describe an extension for the case when the observed time profiles are modelled nonparametrically through penalized splines. Two real data applications are presented.     

关注行业技术进步弘扬企业自主创新成果

科技期刊作为传播科技成果的主要载体,必须立足于报道本专业学科发展动向,关注本行业技术进步及企业自主创新成果,集中反映本行业前沿技术、热点及趋向性问题,以充分发挥科技载体的导向、引领功能,帮助和推动行业的自主创新及其科研成果的面世.     

PSC评分偏误再探

国家普通话水平测试(PSC)在经历了十年的运行之后,测试研究已逐步趋向于深层次方向的问题探讨,对评分偏误现象及造成评分偏误的因素的研究是其中的一个方面。对造成评分偏误的因素的分析除了要关注测试本身在设计上的一些因素之外,还要关注汉语的特点、测试员的因素以及在测试过程中的各种外在因素。此文同时还试图通过对各种制约因素的梳理,探讨不同等级之间的客观的评分差异。     

规范减轻我国农民负担问题的探讨

农民问题一直是“三农”问题的核心 ,而农民负担过重问题一直是困扰着我国农村经济发展的因素。虽然近年来的农村税费改革在一定程度上减轻了农民负担 ,但它只是从农村内部的分配关系上来减轻农民负担 ,非治本之策。只有力求站在宏观视野的角度 ,从改革城市偏向的分配政策、改革现行的行政体制这两大方面对农民总负担加以全面分析 ,才能提出更为切实有效的规范性措施