修理延迟的单部件系统的可靠性分析

分析了修理延迟的单部件可修系统,系统包括正常、待修、修理三种状态。文中假定系统的寿命分布、等待修理时间和修理时间均为一般分布,利用马尔可夫更新过程的方法,可获得可靠度、可用度、故障频率等一系列可靠性指标。     

匈奴人口的计算方法与其社会制度

对于匈奴人口数额的探究,胡君泊首倡以匈奴用兵数推计其人口数之说。吕思勉采用贸谊“五口一卒”认为:“取其丁壮之数,以五乘之即得矣”,并计算出300万的结果。马长寿据《汉书》30余万精兵,以5乘得150万。林幹据《史记》40万,乘得200万。欧阳熙则说在150万至300万上下。但冒顿前期匈奴中异族骑士多,“五口一卒”不符合匈奴社会,皆不宜用来计算匈奴人口。以此推测的结果已不可靠,再用来论证其他问题更不可靠。     

经典信度理论和概化理论的计量学透视

从计量学的角度分析了经典信度理论和概化理论的局限、错误和无力,并重点揭示了经典理论和概化理论几个方面的问题.经典理论由于采用了相关分析进路,既无力应对多不确定度源的测量情景,也无法较好地满足实践对条件不确定度的要求.概化理论虽然可以同时考虑多个不确定度源,但由于技术上采用了方差分析进路,即使使用得当,也不能够很好地解决条件不确定度问题.     

电化教学闭路电视系统前端部分的设计

从实用的角度出发 ,概述了电化教学闭路电视系统前端部分的设计思路 ,从频道设置、线路设计、电平计算、设备选型等方面具体阐述了电化教学闭路电视系统前端设计的基本概念和方法。该系统方案可作为一般学校设计电化教学闭路电视系统时的参考     

Advancing OSCM scientific knowledge by replicating empirical findings: Step-by-step procedure and illustration for transformative replication endeavors

Replication endeavors contribute to the accumulation of scientific evidence about previously reported findings and are crucial for scientific progress. Replication studies are, however, often discouraged and rarely published in the operations and supply chain management (OSCM) discipline. In this article, we offer a framework for replications consisting of two complementary tables. This framework recognizes two types of replications already defined in the literature (i.e., The Exact (EXT) Replication and the Methods-Only (MTD) Replication) and adds to these two new types (i.e., the Bounded-Conceptual-Extension (BCE) Replication and the Transformative (TRF) Replication). The framework clarifies what constitutes replications, forms of replication endeavors, and their purposes. Importantly, we also differentiate replication endeavors from reproducibility tests, robustness checks, and post hoc analyses. Moreover, we describe a seven-step procedure to guide the design, execution, and presentation of replication endeavors, illustrating these steps by conducting a TRF Replication that incorporates, at the same time, a BCE Replication and an MTD Replication of Polyviou et al. (2018). The proposed framework and seven-step procedure hopefully motivate OSCM scholars to embrace replications as valuable scientific endeavors that can yield corroborating evidence to bolster confidence in previously reported findings and, better yet, provide new nuanced findings to advance precise scientific understanding of past and new OSCM phenomena.     

乡村中学教师体质健康满意度量表的编制--基于贵州乡村教师的调查

为有效评估乡村中学教师的体质健康现状,在开放性访谈和专家评估的基础上,初步编制了“乡村中学教师体质健康满意度量表”,继而以贵州乡村中学教师为研究对象,分别进行题项分析、探索性因素分析和验证性因素分析,最终形成正式量表。研究结果显示,乡村中学教师的体质健康满意度量表由生理满意和运动满意两个因子构成。信效度分析表明,所编制的量表符合心理测量学的要求,因此,该量表是一个适合评估乡村中学教师体质健康满意度的有效工具。     

Reliability analysis of man–machine systems using fuzzy cognitive mapping with genetic tuning

This article offers a method for analyzing the reliability of a man–machine system (MMS) and ranking of influencing factors based on a fuzzy cognitive map (FCM). The ranking of influencing factors is analogous to the ranking of system elements the probabilistic theory of reliability. To approximate the dependence of “influencing factors—reliability,” the relationship of variable increments is used, which ensures the sensitivity of the reliability level to variations in the levels of influencing factors. The novelty of the method lies in the fact that the expert values of the weights of the FCM graph edges (arcs) are adjusted based on the results of observations using a genetic algorithm. The algorithm's chromosomes are generated from the intervals of acceptable values of edge weights, and the selection criterion is the sum of squares of deviations of the reliability simulation results from observations. The method is illustrated by the example of a multifactor analysis of the reliability of the “driver–car–road” system. It is shown that the FCM adjustment reduces the discrepancy between the reliability forecast and observations almost in half. Possible applications of the method can be complex systems with vaguely defined structures whose reliability depends very much on interrelated factors measured expertly.     

Combining evidence from clinical trials in conditional or accelerated approval

Conditional (European Medicines Agency) or accelerated (U.S. Food and Drug Administration) approval of drugs allows earlier access to promising new treatments that address unmet medical needs. Certain post-marketing requirements must typically be met in order to obtain full approval, such as conducting a new post-market clinical trial. We study the applicability of the recently developed harmonic mean ${\chi }^2$-test to this conditional or accelerated approval framework. The proposed approach can be used both to support the design of the post-market trial and the analysis of the combined evidence provided by both trials. Other methods considered are the two-trials rule, Fisher's criterion and Stouffer's method. In contrast to some of the traditional methods, the harmonic mean ${\chi }^2$-test always requires a post-market clinical trial. If the $p$-value from the pre-market clinical trial is $\ll 0.025$, a smaller sample size for the post-market clinical trial is needed than with the two-trials rule. For illustration, we apply the harmonic mean ${\chi }^2$-test to a drug which received conditional (and later full) market licensing by the EMA. A simulation study is conducted to study the operating characteristics of the harmonic mean ${\chi }^2$-test and two-trials rule in more detail. We finally investigate the applicability of these two methods to compute the power at interim of an ongoing post-market trial. These results are expected to aid in the design and assessment of the required post-market studies in terms of the level of evidence required for full approval.     

隧道岩体抗力模式的随机-模糊估计方法

指出隧道结构抗力是同时含有随机性和模糊性的随机－模糊变量，提出了实用于这类变量的随机－模糊统计方法，包括随机－模糊均值和方差，以及随机－模糊概率分布的估计等。对应的传统随机方法作为一种特例被包含于其中。     

软件开发中的测试技术

在分析了软件测试重要性的基础上 ,提出了软件测试的五大原则 ,指出软件测试的内容和步骤应基于软件生命周期的全过程 ,并就测试方法、测试策略的合理选择进行了阐述。通过对测试时间、测试成本和可靠度的关系的分析 ,给出了软件最佳测试时间的确定方法 ,并对测试工作的可靠性评价进行了探讨