Analyzing survival curves at a fixed point in time for paired and clustered right-censored data

In clinical trials, information about certain time points may be of interest in making decisions about treatment effectiveness. Therefore, rather than comparing entire survival curves, researchers may wish to focus the comparison on fixed time points with potential clinical utility. For two independent samples of right-censored data, Klein et al. (2007) compared survival probabilities at a fixed time point by studying a number of tests based on transformations of the Kaplan-Meier estimators of the survival function. To compare the survival probabilities at a fixed time point for paired right-censored data or clustered right-censored data, however, their approach requires modification. In this paper, we extend the statistics to accommodate possible within-pair and within-cluster correlation. We use simulation studies to present comparative results. Finally, we illustrate the implementation of these methods using two real data sets.     

长白山区林蛙养殖实用技术浅析

林蛙营养丰富、经济价值特别高,越来越被人们所喜爱。林蛙养殖在长白山区已成为重要产业项目,其养殖户及养殖规模在不断增加和扩大,其现有符合林蛙养殖自然条件的区域已几近饱和。如何提高林蛙单产已成为当地林蛙养殖需要迫切解决的问题。本文通过多年的养殖实践,总结了长白山区林蛙养殖如何通过培育林蛙优良品质、提高林蛙成活率,林蛙安全越冬和疾病防治等技术措施,实现在现有养殖规模下提高林蛙单产,增加林蛙养殖效益进行了探讨。     

Mixture cure models for multivariate survival data

Mixture cure models (MCMs) have been widely used to analyze survival data with a cure fraction. The MCMs postulate that a fraction of the patients are cured from the disease and that the failure time for the uncured patients follows a proper survival distribution, referred to as latency distribution. The MCMs have been extended to bivariate survival data by modeling the marginal distributions. In this paper, the marginal MCM is extended to multivariate survival data. The new model is applicable to the survival data with varied cluster size and interval censoring. The proposed model allows covariates to be incorporated into both the cure fraction and the latency distribution for the uncured patients. The primary interest is to estimate the marginal parameters in the mean structure, where the correlation structure is treated as nuisance parameters. The marginal parameters are estimated consistently by treating the observations within the cluster as independent. The variances of the parameters are estimated by the one-step jackknife method. The proposed method does not depend on the specification of correlation structure. Simulation studies show that the new method works well when the marginal model is correct. The performance of the MCM is also examined when the clustered survival times share common random effect. The MCM is applied to the data from a smoking cessation study.     

小议苏州园林对当代公园设计启示

苏州园林具有的独特艺术风格在世界造园史中有重要的意义。其设计思想和技巧都是宝贵资产,许多优秀的设计经验对于现代造园是很大的启示。本文通过对苏州园林历史发展、整体布局、艺术特点的分析,在功能分区、元素风格、叠石理水、花木种植、建筑风格等方面进行研究后寻找出苏州园林造园思想对现代公园设计启示,将现代公园的设计理念与中国造园原则相统一,现代公园的诸多因素与苏州园林的造园形式相结合,对现代造园有推动作用。     

Computation of probabilities of survival/failure of technical,economic systems/structures by means of piecewise linearization of the performance function

The computation of the probability of survival/failure of technical/economic structures and systems is based on an appropriate performance or so-called (limit) state function separating the safe and unsafe states in the space of random model parameters. Starting with the survival conditions, hence, the state equation and the condition for the admissibility of states, an optimizational representation of the state function can be given in terms of the minimum value function of a closely related minimization problem. Selecting a certain number of boundary points of the safe/unsafe domain, hence, on the limit state surface, the safe/unsafe domain is approximated by a convex polyhedron. This convex polyhedron is defined by the intersection of the half spaces in the parameter space generated by the tangent hyperplanes to the safe/unsafe domain at the selected boundary points on the limit state surface. The approximative probability functions are then defined by means of the resulting probabilistic linear constraints in the parameter space. After an appropriate transformation, the probability distribution of the parameter vector can be assumed to be normal with zero mean vector and unit covariance matrix. Working with separate linear constraints, approximation formulas for the probability of survival of the structure are obtained immediately. More exact approximations are obtained by considering joint probability constraints. In a second approximation step, these approximations can be evaluated by using probability inequalities and/or discretizations of the underlying probability distribution.     

银行信贷风险的测量与控制

信贷风险是银行资产业务中最直接、经常性的风险．本文分析了目前金融风险测量 的主流技术VAR模型及其在信贷风险控制上的不足,从信贷风险产生的根源——企业破产深 层次角度,对企业破产风险状态的识别及破产概率进行了研究,提出基于生存函数的信贷风 险控制模型,并给出仿真计算案例．     

基于功耗模型的无线传感器网络节点生存模式评估

作为一种能量受限网络,无线传感器网络节点能耗评估具有重要意义。分析组成无线传感器网络节点各个单元功耗与状态的关系,建立基于节点工作状态的功耗模型,提出节点生存模式评估方法。给出典型节点生存模式实验用例,在振动检测实验平台上进行相关参数测量与验证。实验数据表明：该方法优于Petri网模型,可为无线传感器网络节点节能优化提供较为可靠的依据。     

Robust satisficing and the probability of survival

Concepts of robustness are sometimes employed when decisions under uncertainty are made without probabilistic information. We present a theorem that establishes necessary and sufficient conditions for non-probabilistic robustness to be equivalent to the probability of satisfying the specified outcome requirements. When this holds, probability is enhanced (or maximised) by enhancing (or maximising) robustness. Two further theorems establish important special cases. These theorems have implications for success or survival under uncertainty. Applications to foraging and finance are discussed.     

高校新媒体艺术专业的生存语境及其应对

从事数码新媒体艺术的研究与学习,软件并不是终结者。人与机器的关系、人与社会的关系、人与生活的关系,乃至不同学科,不同技术之间的关系,只有通过学科文化这个特殊的载体,才能将机器、地域、人的精神与情感、文化与思想上升到进行自由的对话与融合这样一个境界,才能在不同的领域找到契合．点。文章从新媒体艺术专业的生存语境和发展应对策略的认识来关注这一全新的专业。提出了价值取向的专业定位和培养目标,以及专业建设应注重的四个要义。     

中西文化差异在英汉语言中的表现

在英语语言的学习中,了解英语国家的知识背景和文化特征有助于对语言内涵的了解,有助于避免因文化冲突造成的误解。文章对英汉两种语言在文化特征上的不同表现,分析了中西文化的差异。