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81.
This paper considers the optimal design problem for multivariate mixed-effects logistic models with longitudinal data. A decomposition method of the binary outcome and the penalized quasi-likelihood are used to obtain the information matrix. The D-optimality criterion based on the approximate information matrix is minimized under different cost constraints. The results show that the autocorrelation coefficient plays a significant role in the design. To overcome the dependence of the D-optimal designs on the unknown fixed-effects parameters, the Bayesian D-optimality criterion is proposed. The relative efficiencies of designs reveal that both the cost ratio and autocorrelation coefficient play an important role in the optimal designs.  相似文献   
82.
Wang  Dewei  Jiang  Chendi  Park  Chanseok 《Lifetime data analysis》2019,25(2):341-360

The load-sharing model has been studied since the early 1940s to account for the stochastic dependence of components in a parallel system. It assumes that, as components fail one by one, the total workload applied to the system is shared by the remaining components and thus affects their performance. Such dependent systems have been studied in many engineering applications which include but are not limited to fiber composites, manufacturing, power plants, workload analysis of computing, software and hardware reliability, etc. Many statistical models have been proposed to analyze the impact of each redistribution of the workload; i.e., the changes on the hazard rate of each remaining component. However, they do not consider how long a surviving component has worked for prior to the redistribution. We name such load-sharing models as memoryless. To remedy this potential limitation, we propose a general framework for load-sharing models that account for the work history. Through simulation studies, we show that an inappropriate use of the memoryless assumption could lead to inaccurate inference on the impact of redistribution. Further, a real-data example of plasma display devices is analyzed to illustrate our methods.

  相似文献   
83.
通过对某大型施工企业多个铁路、公路施工项目部的调查,总结了企业当前投标优化方面存在的问题。针对企业以铁路、公路项目为主业的特点,提出了优势项目滚动发展、建立有效激励制度、做好投标准备、优化施工组织设计、应用报价技巧等优化对策。对于施工企业改善市场经营效果,提高中标质量,增加项目盈利有重要的借鉴作用。  相似文献   
84.
A new set of alternative socioeconomic scenarios for climate change researches—the shared socioeconomic pathways (SSPs)—includes for the first time a more comprehensive set of demographic conditions on population, urbanization, and education as the central scenario elements, along with other aspects of society, in order to facilitate better analyses of challenges to climate change mitigation and adaptation. However, it also raises a new question about the internal consistency of assumptions on different demographic and economic trends under each SSP. This paper examines whether the interactions between the demographic and economic factors implied by the assumptions in the SSP projections are consistent with the research literature, and whether they are consistently represented in the projection results. Our analysis shows that the interactions implied by the demographic assumptions in the SSPs are generally consistent with findings from the literature, and the majority of the assumed relationships are also evident in the projected trends. It also reveals some inconsistency issues, resulting mainly from the use of inconsistent definitions of regions and limitations in our understanding of future changes in the patterns of interactions at different stages of socioeconomic development. Finally, we offer recommendations on how to improve demographic assumptions in the extended SSPs, and how to use the projections of SSP central elements in climate change research.  相似文献   
85.
在现代社会,大学生应具备的公民品质包括"讲德性"、"守规则"、"有理性"以及"重参与"等四个方面的内容。目前,由于我国公民教育起步较晚,大学校园缺乏公民教育的文化氛围,大学生的公民品质还有待于进一步塑造和培养。利用公民教育塑造大学生的公民品质,需要引导大学生追求优良的公民品质;需要以思想政治理论课为重要载体,加强大学生公民教育;需要在校园生活中开发利用更多的公民教育资源;需要进一步规范和丰富大学生公民教育内容,有效开展公民教育。  相似文献   
86.
针对Web服务组合问题,提出一种基于先进先出通信通道的Web服务组合模型,支持Web服务的层次性组合。给出了该模型的形式化定义及Web服务描述语言与该模型的对应关系。介绍了用于建模Web服务行为的Pi-演算语言的基本语法及操作语义。通过一个旅游路线预定服务研究了Web服务组合模型的实际应用。  相似文献   
87.
Quasi-likelihood nonlinear models (QLNMs) are an extension of generalized linear model and include a widen class of models as special cases. This article investigates some diagnostic methods in QLNMs. An equivalency between a case-deletion model and a mean-shift outlier model in QLNM is established. Two simulation study and a real dataset are used to illustrate the proposed diagnostic methods.  相似文献   
88.
张岱晚年所著《於越有明三不朽图赞》,以图像加赞辞的形式,辑录了绍兴有明一代先贤的事迹,汇成人物传记式圣贤画谱.鲁迅家藏该著作珍本,曾于1912、1913年两次补绘插图,补足跋语,周建人抄录赞文,鲁迅又两次购藏此书三册,以表达对绍兴先贤和文学前辈的敬意.本文是学界首次整理鲁迅补录手迹,赏析鲁迅唯一存世手绘圣贤人物画像,基于"三不朽"的儒教内涵,赞文体裁的文学性,鲁迅对张岱文章史著风格的传承,勾连"反圣贤"的白话小说《阿Q正传》,于此个案回溯流转的文脉深处,论证所谓"沉默期"鲁迅钞校古籍与新文学创作之间的对话关系.  相似文献   
89.
Analysis of massive datasets is challenging owing to limitations of computer primary memory. Composite quantile regression (CQR) is a robust and efficient estimation method. In this paper, we extend CQR to massive datasets and propose a divide-and-conquer CQR method. The basic idea is to split the entire dataset into several blocks, applying the CQR method for data in each block, and finally combining these regression results via weighted average. The proposed approach significantly reduces the required amount of primary memory, and the resulting estimate will be as efficient as if the entire data set is analysed simultaneously. Moreover, to improve the efficiency of CQR, we propose a weighted CQR estimation approach. To achieve sparsity with high-dimensional covariates, we develop a variable selection procedure to select significant parametric components and prove the method possessing the oracle property. Both simulations and data analysis are conducted to illustrate the finite sample performance of the proposed methods.  相似文献   
90.
江苏省海州湾地区海岛资源丰富,优势明显,十分适合于海岛户外体育拓展.研究了该地区海岛体育资源特点和现状,分析了在海州湾地区构建大学生海岛户外体育拓展基地的优势,在此基础上,提出了构建大学生海岛户外体育拓展基地的模式选择.  相似文献   
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