Another Remark on the Alternative Expectation Formula

Students in a calculus-based probability course will often see the expectation formula for nonnegative continuous random variables in terms of the survival function. This alternative expectation formula has a wide spectrum of applications. It is natural to ask whether there is a multivariate version of this formula. This note gives an affirmative answer by establishing such a formula using two different approaches. The two approaches employed in this note correspond to the two approaches for the univariate case. Supplementary materials for this article are available online.     

不同入药部位中药元素含量的比较

用t检,比较了《兽药典》中113味以花果仁入药中药、101味以茎叶入药中药、105味以根须入药中药及48味其它入药中药11种无机元素含量,结果首次表明：茎叶类中药Zn含量显著高于花果仁、根须及其它三类中药;花果仁类中药P含量显著高于茎叶、根须二类中药;其它入药中药类Fe、Cu的含量显著高于花果仁、茎叶及根须类三类中药。     

内蒙古中西部地区村镇民居抗震设防研究

通过对内蒙古中西部地区村镇民居结构特点的分析及包头６．４级地震对此类房屋的震害分析,提出应重视农村民居的抗震设防研究,并提出可行的抗震设防措施。     

周转件构成的可修复系统的可靠性分析

系统在运行期间因部件失效而发生故障,进行更换维修后,系统部件的使用时间分布发生变化,系统可靠性指标的值也随之变化,对此情况下系统可靠性分析方法进行了研究。将一定范围内同类部件的整体看作系统,并考察全部由周转件构成的系统,通过对各个时刻系统内部件的使用时间以及维修次数分布建立数学模型,得到了系统可靠度随系统运行时间的增加而减小,系统部件更换率随系统运行时间增加而增加的结论。并通过航空公司的实际数据对结果进行了验证。分析结果为备件采购计划、部件梯次使用计划和维修策略的制订具有重要意义。     

Demystifying the Integrated Tail Probability Expectation Formula

ABSTRACT

Calculating the expected values of different types of random variables is a central topic in mathematical statistics. Targeted toward students and instructors in both introductory probability and statistics courses and graduate-level measure-theoretic probability courses, this pedagogical note casts light on a general expectation formula stated in terms of distribution and survival functions of random variables and discusses its educational merits. Often consigned to an end-of-chapter exercise in mathematical statistics textbooks with minimal discussion and presented under superfluous technical assumptions, this unconventional expectation formula provides an invaluable opportunity for students to appreciate the geometric meaning of expectations, which is overlooked in most undergraduate and graduate curricula, and serves as an efficient tool for the calculation of expected values that could be much more laborious by traditional means. For students’ benefit, this formula deserves a thorough in-class treatment in conjunction with the teaching of expectations. Besides clarifying some commonly held misconceptions and showing the pedagogical value of the expectation formula, this note offers guidance for instructors on teaching the formula taking the background of the target student group into account.     

基于SLS技术的非均质材料零件成型研究

基于SLS成型的非均质材料零件是一种变密度材料零件。预热温度和激光能量是影响SLS成型零件烧结密度的主要因素。通过实验调整预热温度和激光能量的参数,然后用MATALB对实验数据进行分析处理,得到烧结密度数学模型,达到对基于SLS成型的非均质材料零件烧结密度进行控制的目的。     

明清时期我国基层官制的量变与质变

作为古代中国富有特色的基层官制,明至清中期,县官制度经历其最后一次渐进性发展,在县官的铨选、任用、致仕、品级、待遇、管理等制度上不断加以完善,有效地实现了制度规定、职责实现与地方社会类型的高度统一。但是经过发展的基层官制仍然没有摆脱"钱谷刑名"的核心职责,所以这一时期的县官制度仍然呈现出一种量变。晚清时代,为适应中国社会性质的蜕变,基层官制也发生了根本性的变化。随着地方自治的推行和基层官制的行政、司法权分离,传统的县官制度逐渐为近代镇(乡)官制度所取代。至此,明清基层官制经历了从量变到质变、从县官到镇(乡)官的历史性变革。尽管如此,作为一种历史悠久的基层官制,传统县官制度的合理性内核仍为现代所需。     

古西亚装饰风格研究初探

古代西亚的广大地区（现两河流域和伊朗高原）是人类最早进入文明的地区之一。众多的民族依靠他们的勤劳和智慧,共同创造了古西亚艺术设计的高度成就。其成就主要体现在陶器、金银器和染织品的设计和制作方面,是在古代西亚地区休养生息的各民族集体智慧的结晶。     

Is there still such a thing as the ‘European social model'?

This article presents a definition and characterisation of the ‘European social model’ (ESM), admitting the existence of variants and increasing heterogeneity in institutional and social contexts within the EU in the wake of successive enlargements. The constituent parts of the ESM are compared with data observed in the different countries, in search of empirical evidence of the ESM‘s position as a distinctive model of development, characteristic of Western Europe as opposed to the paths taken by other non‐European developed OECD countries.     

景德镇陶瓷品牌激活管理主体确定的博弈分析

景德镇陶瓷是历史悠久的区域品牌,然而历尽风雨沧桑,品牌价值极度衰退。因此,有必要实施品牌激活战略。而品牌激活战略的实施首先需要一个强有力的管理者来推动。文章针对这一问题,采用博弈论的方法对最适宜的区域品牌管理者进行了分析。通过对以不同管理主体为主的景德镇陶瓷区域品牌激活管理进行博弈分析。并对以陶瓷厂商、行业协会、地方政府为管理主体的三种管理模式利弊进行了剖析,提出了景德镇陶瓷区域品牌最优管理主体系统,根据区域品牌管理的基本流程来刻画其激活管理方式和实施步骤。