Book Reviews

Books reviewed:
M Hollander and D Wolfe, Nonparametric Statistical Methods
T Leonard and J.S.J Hsu, Bayesian Methods     

启动压力其实并不存在

低渗透储层存在许多研究误区,启动压力梯度便是其一。低渗透储层孔隙欠发育,渗透率低,产能也较低,压力在其中的传播速度较慢,施以压力梯度之后,产量的响应需要较长时间。实验过程将微弱的流量误认为是0,因而导致了启动压力梯度的实验假象。实测的启动压力梯度数值太高,对油气生产没有任何指导意义。中高渗透储层没有启动压力梯度,低渗透储层也不应该有。固体和流体都不存在启动压力,油气也不可能存在。     

Monotonicity and comparability in ballistic missile defense systems

A general framework is provided for modeling Ballistic Missile Defense (BMD) systems that are driven by stochastically monotone decreasing discrete time Markov chains, not necessarily temporally homogeneous. Based on a lexicographical ordering of defense vectors, the notions of stochastic monotonicity and comparability for such systems are investigated. Then conditions under which these systems are monotone and comparable are established. For any such BMD system, it is shown that the number of missiles penetrating the defense is decreasing in the likelihood ratio, and the elements of the associated one-step nonhomogeneous transition probability matrix are totally positive of order 2. In addition, the number of missiles penetrating the defense under uniform firing doctrine is shown to be smaller in the reversed hazard rate order than the number of missiles penetrating the defense under random firing doctrine. Particular performance measures are also shown to be monotone and comparable.     

The impact of education on third births. A multilevel discrete-time hazard analysis

We propose to use multilevel discrete-time hazard models to assess the impact of societal and individual level covariates on the timing and occurrence of third births. We focus mainly on the impact of educational attainment on third births across 15 European countries. From the analysis in this paper, the effect of education on the propensity to have a third child is found to be negative. This education effect is not significantly weakened by the Nordic countries, but living in Scandinavia does increase the hazard for a third birth.     

Simultaneous Modelling of Survival and Longitudinal Data with an Application to Repeated Quality of Life Measures

In biomedical studies, interest often focuses on the relationship between patients characteristics or some risk factors and both quality of life and survival time of subjects under study. In this paper, we propose a simultaneous modelling of both quality of life and survival time using the observed covariates. Moreover, random effects are introduced into the simultaneous models to account for dependence between quality of life and survival time due to unobserved factors. EM algorithms are used to derive the point estimates for the parameters in the proposed model and profile likelihood function is used to estimate their variances. The asymptotic properties are established for our proposed estimators. Finally, simulation studies are conducted to examine the finite-sample properties of the proposed estimators and a liver transplantation data set is analyzed to illustrate our approaches.     

政策性农业保险中投保农户道德风险的博弈分析

政策性农业保险是政府支持农业生产、稳定农户收入、促进农村可持续发展的农业支持保护体系的重要组成部分,近几年逐渐在全国各省市进行试点实施。农业保险市场上的信息不对称易引起逆向选择和道德风险问题,严重影响政策性农业保险市场的健康发展,制约农业保险作用的发挥。因此,有必要对政策性农业保险中投保农户的道德风险问题进行分析,以降低道德风险的发生,促进政策性农业保险的发展。     

通矿集团危险源调查及防范

针对通矿集团自然赋煤条件复杂多变、管理不到位等具体情况,通过实行问卷调查和实地考察,分析了通矿集团危险源存在状况、种类及各危险源的危险系数,并提出建立安全生产体制,增加安全生产投入等防范措施。研究结论对保证通煤集团安全生产有指导作用。     

对品牌不当延伸的思考

文章界定了品牌延伸的内涵,分析了品牌延伸的动力机制,阐述了品牌不当延伸的主要危害,如引起消费者的不良联想、破坏原有品牌形象、降低消费者对品牌的忠诚度及失去老顾客、使原有品牌价值流失等。就如何正确开展品牌延伸提出了围绕核心价值开展品牌延伸、遵循品牌延伸"近亲繁殖有益"原则、根据产品的不同分类来实行多品牌命名等观点。     

一类新的自适应非单调谱投影梯度法

给出了求解凸约束优化的一类新的自适应非单调谱投影梯度法.通过引入具有自适应性的权重参数,使算法在迭代过程中能自动调节非单调策略. 在适当条件下证明了算法的收敛性.数值试验结果表明,该算法在一定程度上能减少在线搜索过程中对非单调参数M的依赖.