Testing for Imperfect Debugging in Software Reliability

This paper continues the study of the software reliability model of Fakhre-Zakeri & Slud (1995), an "exponential order statistic model" in the sense of Miller (1986) with general mixing distribution, imperfect debugging and large-sample asymptotics reflecting increase of the initial number of bugs with software size. The parameters of the model are θ (proportional to the initial number of bugs in the software), G (·, μ) (the mixing df, with finite dimensional unknown parameter μ, for the rates λ _i with which the bugs in the software cause observable system failures), and p (the probability with which a detected bug is instantaneously replaced with another bug instead of being removed). Maximum likelihood estimation theory for (θ, p , μ) is applied to construct a likelihood-based score test for large sample data of the hypothesis of "perfect debugging" ( p = 0) vs "imperfect" ( p > 0) within the models studied. There are important models (including the Jelinski–Moranda) under which the score statistics with 1/√ n normalization are asymptotically degenerate. These statistics, illustrated on a software reliability data of Musa (1980), can serve nevertheless as important diagnostics for inadequacy of simple models     

试论唐末五代晋梁争雄的政治策略博弈

唐末五代的晋梁之争,在政治策略上,双方开始都打出尊王的旗号,极力利用唐室余威,扩大各自的政治影响,为自身的发展制造声势。前期朱全忠以勤王之名招降平叛、扩张地盘, 特别是在解救昭宗于凤翔之后,曾经达到自己政治声望的顶点。但在朱全忠挟持昭宗迁都洛阳, 并弑君篡代之后,他不仅丧失了挟天子以令诸侯,尊王伐叛的政治优势,而且自毁形象,失去人心,为其政敌提供了匡复唐室、分庭抗礼的口实,把宝贵的政治资源和政治优势拱手让给了竞争对手。晋方反而以正统自居,以复兴唐室为号召,赢得了更多的政治资源和政治支持。随后晋梁双方军事形势的演变皆与政治策略的博弈有很大关系。     

试析网络经济的产业组织特征

网络经济作为一种新型经济形态 ,具有不同于工业经济条件下的新的作用效应。网络经济效应引起产业组织特征的变化 ,这种变化具体表现在交易费用、规模经济、垄断形成机制以及垄断与竞争的关系等方面。     

Recurrent events analysis in the presence of time-dependent covariates and dependent censoring

Summary.  Recurrent events models have had considerable attention recently. The majority of approaches show the consistency of parameter estimates under the assumption that censoring is independent of the recurrent events process of interest conditional on the covariates that are included in the model. We provide an overview of available recurrent events analysis methods and present an inverse probability of censoring weighted estimator for the regression parameters in the Andersen–Gill model that is commonly used for recurrent event analysis. This estimator remains consistent under informative censoring if the censoring mechanism is estimated consistently, and it generally improves on the naïve estimator for the Andersen–Gill model in the case of independent censoring. We illustrate the bias of ad hoc estimators in the presence of informative censoring with a simulation study and provide a data analysis of recurrent lung exacerbations in cystic fibrosis patients when some patients are lost to follow-up.     

补偿法在物理解题中的应用

通过例题讨论补偿法解题的技巧 ,从而培养学生解题能力     

33名中青年教师讲课比赛成绩及相关因素分析

评价教师讲课质量是一项复杂的工作 ,不同的评价者 (如教学管理干部、教师、学生 ) )对教师讲课质量的评价存在较大差异。本文通过 3 3名中青年教师讲课比赛成绩分析 ,提出了影响教师讲课质量的相关因素及解决办法。     

生物组织中激光传输的Monte-Carlo研究

Monte-Carlo模拟了波长为515nm的激光在肺组织中传播情况,详细讨论了高斯光束和圆平面光束在组织中的吸收和光能流率的分布情况,并与波长635nm激光在组织中漫反射强度随时间变化的结果相比较。结果表明激光光斑形状选择对激光在组织中传播有重要的影响作用,并且得出在生物组织中近红外光波的穿透性比较强,更便于应用于生物医学。     

计算全息图再现像的光强补偿

考虑到光栅衍射因子作用会影响到计算全息图再现像时的光强分布，造成再现及其共轭像边缘暗、中央亮的情况，在物采样时，加进一反射因子，使再现光强得到了补偿。     

双元营销能力平衡、战略地位优势与新创高技术服务企业绩效

鉴于人们对双元营销能力的平衡及其影响企业绩效的路径机制、边界条件以及服务企业如何平衡双元营销能力等知之甚少,着眼于中国经济转型背景下的新创高技术服务企业,遵循能力-地位-绩效经典理论逻辑,构建基于能力视角的创始团队双元营销能力对战略地位优势和绩效动态交互影响的概念模型.采用SPSS 19.0、AMOS 17.0和多元层次回归分析方法,对来自长三角、珠三角和海西地区225家企业的调研数据进行统计分析.研究结果表明,创始团队的营销探索能力和营销利用能力均显著提升企业绩效,但路径机制不同,营销探索能力主要通过服务差异化优势的部分中介作用直接和间接影响绩效,营销利用能力则通过服务扩展优势的部分中介作用直接和间接影响绩效;市场竞争强度正向调节营销探索能力与绩效的关系,负向调节营销利用能力与绩效的关系;营销探索能力和营销利用能力具有二元平衡关系,两者交互正向影响绩效.     

企业最优研发强度影响因素实证研究

文章的研究分为两个部分,第一部分通过二项式回归证明了企业绩效与研发强度之间呈倒U型曲线式的相关关系,从而找到了企业的“最优”研发强度;第二部分以该“最优”研发强度为被解释变量,以透明国际发布的CPI指数为解释变量,考察了经济体清廉程度与企业最优研发强度之间的关系。实证结果显示,政治清廉度与企业最优研发强度之间存在显著的正相关关系,这对提升我国企业的研发强度和研发能力具有借鉴意义。