Multiple event times in the presence of informative censoring: modeling and analysis by copulas

Motivated by a breast cancer research program, this paper is concerned with the joint survivor function of multiple event times when their observations are subject to informative censoring caused by a terminating event. We formulate the correlation of the multiple event times together with the time to the terminating event by an Archimedean copula to account for the informative censoring. Adapting the widely used two-stage procedure under a copula model, we propose an easy-to-implement pseudo-likelihood based procedure for estimating the model parameters. The approach yields a new estimator for the marginal distribution of a single event time with semicompeting-risks data. We conduct both asymptotics and simulation studies to examine the proposed approach in consistency, efficiency, and robustness. Data from the breast cancer program are employed to illustrate this research.

     

Bayesian analysis of mixture modelling using the multivariate t distribution

A finite mixture model using the multivariate t distribution has been shown as a robust extension of normal mixtures. In this paper, we present a Bayesian approach for inference about parameters of t-mixture models. The specifications of prior distributions are weakly informative to avoid causing nonintegrable posterior distributions. We present two efficient EM-type algorithms for computing the joint posterior mode with the observed data and an incomplete future vector as the sample. Markov chain Monte Carlo sampling schemes are also developed to obtain the target posterior distribution of parameters. The advantages of Bayesian approach over the maximum likelihood method are demonstrated via a set of real data.     

优选方案定量评价模型研究

在确定评价指标体系的基础上，如何对若干事物或方案进行选优是一个十分有意义的问题．作者利用模糊多目标决策对此进行研究，并通过实例说明该方法的有效性与实用性．     

圆锥轴受扭时静、动力的传递矩阵法求解

本文提出了圆锥轴受扭时静、动力的传递矩阵。该方法简便实用,适于工程技术人员在微机上应用。     

“豆豆豆”品牌，点点富饶心

大连富饶企业集团“豆豆豆”系列健康食品获“辽宁省著名商标”。这事发生在2005年1月12日。稍早一天，即2005年1月11日．企业集团旗下富饶日化公司生产的化妆产品“艾肤琳美白祛斑霜”、“艾肤琳美白精华露”，“艾肤琳防晒隔离霜”又获“国家特殊用途化妆品卫生许可”。这使大连富饶企业在营造“豆豆豆”品牌的基础上，又上了一个新台阶，进一步扩大了企业产品品种和产品格局。     

鞋用聚氨酯胶粘剂的改性研究

本文以二甘醇代替其它多元醇与已二酸反应合成聚酯多元醇 ,再以合适的OH/NCO比与二异氰酸酯TDI生产聚氨酯胶粘剂 .成本低 ,各项粘接性能达到或超过同类产品 .同时利用了制备乙二醇时的副产品二甘醇 ,一举数得     

文化转型与鲁迅的直译理论

对鲁迅的直译理论和翻译实践的评价历来微词颇多,角度也多是直译与意译的“信、达、雅”之争。在多元系统论的理论框架下,鲁迅的直译理论有其文化意义和时代特征,鲁迅的直译理论所植根的思想文化土壤使其具有科学性的同时也带有必然性。     

Risk,trust and knowledge networks in farmers’ learning

This study reports on New Zealand dairy farmers’ access to and use of information as mediated through conditions of risk and trust within the context of their interpersonal social networks. We located participants’ reports of their information use within their perceived environments of trust and risk, following Giddens's [1990. The consequences of modernity. Polity Press, Stanford, CA] typology of trust and risk in pre-modernity and modernity. The research participants were constant users of interpersonal and print information from numerous sources, and monitored their incoming data in the light of strategic needs, reflecting their roles as both farming practitioners and business owners. Socio-spatial knowledge networks (SSKNs) combine individuals’ explanatory cognitive models of information acquisition and use with a micro-geographical analysis of their interpersonal networks. The participants showed characteristics of pre-modern, modern and even post-modern society in respect of their use of complex interactional forms, as well as a blending of individualistic and communitarian practices and concerns in their professional and personal lives.     

Simulating the effect of demographic events on the household composition

The aim of this paper is to measure the effects on household composition of changes in demographic events, e.g. mortality, fertility, marriage, divorce. British household data are taken from the General Household Survey and aged by simulation to 2001 using a ‘Most Likely’ model. Subsequently different assumptions of each demographic event are taken from 1991 so that the effects of perturbations within each event can be studied. Special features of the simulation model are the differentiations between cohabitation and marriage and separation and divorce, and the detailed breakdowns of household types such as lone parents into single and previously married women and men with children aged 0–4, 5–15 and 16 and over.     

制造商竞争下闭环供应链的押金返还制度研究

本文研究制造商竞争环境下,政府对闭环供应链成员实施押金返还制度时,废旧电器电子产品的回收决策问题。首先构建了制造商完全垄断情形的闭环供应链基准决策模型,然后考虑制造商之间的竞争,分别构建政府对制造商和对回收商实施押金返还制度的闭环供应链决策模型,最后对结果进行比较和分析。研究表明：押金返还制度可以使新产品的零售价和废旧产品的回购价降低;制造商间的竞争和押金返还制度均可以提高闭环供应链中废旧电器电子产品的回收率;与对制造商实施押金返还制度的情形相比,对回收商实施押金返还制度时闭环供应链的总利润和回收率更高。