A new generalized Weibull distribution in income economic inequality curves

Researchers have been developing various extensions and modified forms of the Weibull distribution to enhance its capability for modeling and fitting different data sets. In this note, we investigate the potential usefulness of the new modification to the standard Weibull distribution called odd Weibull distribution in income economic inequality studies. Some mathematical and statistical properties of this model are proposed. We obtain explicit expressions for the first incomplete moment, quantile function, Lorenz and Zenga curves and related inequality indices. In addition to the well-known stochastic order based on Lorenz curve, the stochastic order based on Zenga curve is considered. Since the new generalized Weibull distribution seems to be suitable to model wealth, financial, actuarial and especially income distributions, these findings are fundamental in the understanding of how parameter values are related to inequality. Also, the estimation of parameters by maximum likelihood and moment methods is discussed. Finally, this distribution has been fitted to United States and Austrian income data sets and has been found to fit remarkably well in compare with the other widely used income models.     

Adherence to three different strategies to prevent early onset GBS infection in newborns

ProblemDespite the introduction of preventive guidelines, no decrease in the incidence of early onset infection was observed.BackgroundEarly onset group B streptococcal (EOGBS) infection is an important cause of neonatal morbidity and mortality.AimOur study was conducted to determine adherence to three guideline-based group B streptococcus (GBS) preventive strategies.MethodsA prospective experimental study clustered by obstetric collaboration region was performed between March 2013 and August 2014 among midwives, obstetricians and paediatricians in the Netherlands. At baseline, the three regions operated according to the Dutch preventive strategy (founded on the risk-based strategy) in order to prevent EOGBS infection, whereas in the study period they followed either the risk-based, the combination or the Dutch strategy. Adherence was measured prospectively per pregnant woman, using predefined core elements of each preventive strategy: identification of risk factors, maternal GBS screening, application of intrapartum antibiotic prophylaxis and observation of the child. Data about adherence to the core elements were collected from medical records, maternal questionnaires and laboratory test results.FindingsIn the three regions, a total of 121 care providers and 1562 women participated.We found an overall adherence of 90% to the risk-based strategy, 57% to the combination strategy and 89% to the Dutch strategy. Adherence to a strategy in case women had EOGBS risk factors was below 20% in all strategies.DiscussionThe majority of women with EOGBS risk factors did not receive the care prescribed by any of three preventive strategies and were not treated optimally.ConclusionThe risk-based and the Dutch strategy are the recommended strategies for implementation.     

ALL-BIAS DESIGNS FOR POLYNOMIAL SPLINE REGRESSION MODELS

Polynomial spline regression models of low degree have proved useful in modeling responses from designed experiments in science and engineering when simple polynomial models are inadequate. Where there is uncertainty in the number and location of the knots, or breakpoints, of the spline, then designs that minimize the systematic errors resulting from model misspecification may be appropriate. This paper gives a method for constructing such all‐bias designs for a single variable spline when the distinct knots in the assumed and true models come from some specified set. A class of designs is defined in terms of the inter‐knot intervals and sufficient conditions are obtained for a design within this class to be all‐bias under linear, quadratic and cubic spline models. An example of the construction of all‐bias designs is given.     

B2C电子商务败因:创新范式研究

B2C电子商务的发展经历了泡沫-失败-复苏的周期,深刻分析其失败的原因,对于今后B2C的发展是有指导意义的。B2C商务模式是一种创新行为,B2C的失败是一种创新行为的失败。本文采用创新理论框架对其失败的原因进行分析。     

增长曲线模型非齐次线性估计的可容许性

讨论增长曲线模型Y =X1BX2 +ε中回归矩阵B的函数C1BC2 的估计L1YL2 +A ,在矩阵损失 (LT2 L1)Y +A - (ST2 XT2 S1X1)B (LT2 L1)Y +A - (ST2 XT2 S1X1)B T 下 ,我们得到了非齐次线性估计L1YL2 +A在非齐次线性估计类Г ={L1YL2 +A|L1:t×p ,L2 ;n×n ,A :t×s均为已知实阵 }中可容许的充要条件 :L1YL2在Г0 ={L1YL2 |L1:t×p ,L2 :n×s均为已知实阵 }中容许且当LT2 XT2 L1X1=ST2 XT2 S1X1时有A =0。     

用于1553总线控制器的存储管理单元设计

从消息队列的数据存储结构定义、存储空间规划和控制过程设计三方面讨论了MIL-STD-1553/1773总线控制器的设计实现。在总线控制器的模块化设计方案中,这三个方面构成了总线控制器的核心模块棗存储管理单元,应用该方案可实现具有多消息自动处理功能的总线控制器。     

Assessing accuracy of a continuous screening test in the presence of verification bias

Summary.  In studies to assess the accuracy of a screening test, often definitive disease assessment is too invasive or expensive to be ascertained on all the study subjects. Although it may be more ethical or cost effective to ascertain the true disease status with a higher rate in study subjects where the screening test or additional information is suggestive of disease, estimates of accuracy can be biased in a study with such a design. This bias is known as verification bias. Verification bias correction methods that accommodate screening tests with binary or ordinal responses have been developed; however, no verification bias correction methods exist for tests with continuous results. We propose and compare imputation and reweighting bias-corrected estimators of true and false positive rates, receiver operating characteristic curves and area under the receiver operating characteristic curve for continuous tests. Distribution theory and simulation studies are used to compare the proposed estimators with respect to bias, relative efficiency and robustness to model misspecification. The bias correction estimators proposed are applied to data from a study of screening tests for neonatal hearing loss.     

基于NET的C/S与B/S混合结构的MIS开发研究

以实际开发经验为基础,介绍了.NET技术特别是VB.NET技术以及ADO.NET、Crystalreports报表技术等在C/S与B/S混合结构管理信息系统开发中的理论与应用。     

Influence diagnostics and outlier tests for semiparametric mixed models

Summary. Semiparametric mixed models are useful in biometric and econometric applications, especially for longitudinal data. Maximum penalized likelihood estimators (MPLEs) have been shown to work well by Zhang and co-workers for both linear coefficients and nonparametric functions. This paper considers the role of influence diagnostics in the MPLE by extending the case deletion and subject deletion analysis of linear models to accommodate the inclusion of a nonparametric component. We focus on influence measures for the fixed effects and provide formulae that are analogous to those for simpler models and readily computable with the MPLE algorithm. We also establish an equivalence between the case or subject deletion model and a mean shift outlier model from which we derive tests for outliers. The influence diagnostics proposed are illustrated through a longitudinal hormone study on progesterone and a simulated example.     

叶芝诗歌创作中的东方神秘主义

叶芝诗歌以东方神秘主义的象征著称于世。玫瑰、狮身人面怪、天鹅和螺旋是叶芝诗歌中具有凸现主题意义的意象。其来源有二 ,对《旧约圣经》抒情诗风格的继承是叶芝诗歌抒情性的直接来源 ,东方神秘主义思想指导下的对中国和日本诗歌的模仿学习是叶芝诗歌抒情性的间接来源