Implementation of a Federated Search System: Resource Accessibility Issues

Abstract

During 2009, the Hilton M. Briggs Library, South Dakota State University, went live with MetaLib, a federated search engine from Ex Libris. This paper presents the implementation process, addresses resource accessibility issues, and suggests a number of resources that can be consulted about these issues. Readers can apply similar strategies to projects involving federated search systems, as many implementation projects involve the same basic considerations presented here. The author did not find any studies specifically focused on configurations of MetaLib resources, so this content should be singularly useful.     

Estimation of Main Effect When Covariates Have Non-Proportional Hazards

The Cox proportional hazards (PH) regression model has been widely used to analyze survival data in clinical trials and observational studies. In addition to estimating the main treatment or exposure group effect, it is common to adjust for additional covariates using the Cox model. It is well known that violation of the PH assumption can lead to estimates that are biased and difficult to interpret, and model checking has become a routine procedure. However, such checking might focus on the primary group comparisons, and the assumption can still be violated when adjusting for many of the potential covariates. We study the effect of violation of the PH assumption of the covariates on the estimation of the main group effect in the Cox model. The results are summarized in terms of the bias and the coverage properties of the confidence intervals. Overall in randomized clinical trials, the bias caused by misspecifying the PH assumption on the covariates is no more than 15% in absolute value regardless of sample size. In observational studies where the covariates are likely correlated with the group variable, however, the bias can be very severe. The coverage properties largely depend on sample size, as expected, as bias becomes dominating with increasing sample size. These findings should serve as cautionary notes when adjusting for potential confounders in observational studies, as the violation of PH assumption on the confounders can lead to erroneous results.     

PMSE performance of two different types of preliminary test estimators under a multivariate t error term

Abstract

In this paper, assuming that the error terms follow a multivariate t distribution, we derive the exact formula for the predictive mean squared error (PMSE) of two different types of pretest estimators. It is shown analytically that one of the pretest estimator dominates the SR estimator if a critical value of the pretest is chosen appropriately. Also, we compare the PMSE of the pretest estimators with the MMSE, AMMSE, SR and PSR estimators by numerical evaluations. Our results show that the pretest estimators dominate the OLS estimator for all combinations when the degrees of freedom is not more than 5.     

More on the Preliminary Test Estimator in Almost Unbiased Liu Regression

This article is concerned with the parameter estimation in linear regression model when it is suspected that the regression coefficients are the subspace of the equality restrictions. The objective of this article is to introduce the preliminary test almost unbiased Liu estimators (PTAULE) based on the Wald (W), the likelihood ratio (LR), and the Lagrangian multiplier (LM) tests and compare the proposed estimators in the sense of the quadratic bias and mean square error (MSE) criterion.     

Likelihood Ratio Order of m-Spacings in Multiple-Outlier Models

This article deals with the multiple-outlier exponential model. The likelihood ratio order between m-spacings of the combined sample is developed, some results extend the conclusions on simple spacings in Wen et al. (2007 Wen , S. , Lu , Q. , Hu , T. ( 2007 ). Likelihood ratio order of spacings of heterogeneous exponential random variables . J. Multivariate Anal. 98 : 743 – 756 .[Crossref], [Web of Science ®] , [Google Scholar]).     

青岛一套表的实践与经验

 企业统计一套表一直是统计制度方法改革和实践中的焦点问题。本文通过对青岛市统计局企业一套表制度实施情况的案例分析,系统界定了企业一套表的概念和内涵,全面展现了企业一套表的运作过程,客观分析了制约企业一套表实施的主要原因,并提出了在现阶段实施企业统计一套表的条件和要求。     

大股东控制影响公司现金持有量的实证分析

 本文结合我国上市公司所面临的内部治理机制特点及外部治理环境,从大股东行为的视角对公司现金持有量的影响因素进行实证分析。在加入年度控制变量、行业控制变量和公司财务特征控制变量后,对三项反映大股东行为特征的因素,即大股东持股比例、大股东属性和制度环境因素对公司现金持有量的影响进行了检验。结果表明,第一大股东持股比例较高的公司持有较多的现金,大股东的高持股比例是其占用企业资金侵占中小股东利益的基础。与国有企业相比,民营企业因遭受较强的外部融资约束而持有较高水平的现金。此外,制度环境的发展程度与公司现金持有水平正相关,表明制度环境较好地区的公司持有较多的现金。     

Analysis of supersaturated designs via the Dantzig selector

A supersaturated design is a design whose run size is not enough for estimating all the main effects. It is commonly used in screening experiments, where the goals are to identify sparse and dominant active factors with low cost. In this paper, we study a variable selection method via the Dantzig selector, proposed by Candes and Tao [2007. The Dantzig selector: statistical estimation when p$p$ is much larger than n$n$. Annals of Statistics 35, 2313–2351], to screen important effects. A graphical procedure and an automated procedure are suggested to accompany with the method. Simulation shows that this method performs well compared to existing methods in the literature and is more efficient at estimating the model size.     

试论离婚之精神损害赔偿制度

离婚之精神损害有离因精神损害和离婚精神损害两种.前者是夫妻一方对另一方构成侵权行为而导致离婚,从而给一方造成精神痛苦,受害方可请求精神损害赔偿.我国新的<婚姻法>确立了这一精神损害赔偿制度,填补了我国婚姻制度的一个空缺.而后者是夫妻一方对另一方并无侵权行为,离婚本身即为构成精神损害之直接原因,如由于第三者插足、婚外恋、夫妻一方被判处徒刑等.这种离婚同样使一方受到精神损害,自然也应得精神损害赔偿.遗憾的是,新的<婚姻法>并未作此规定.因此,要完善我国离婚之精神损害赔偿制度,不仅要使离婚之精神损失赔偿的权利义务主体进一步扩大,把第三者也作为离婚之精神损害赔偿的义务主体,而且还要将离因精神损害赔偿扩大到离婚精神损害赔偿,将因婚外恋、第三者插足、因配偶一方犯罪而被判入狱和其他原因导致离婚的情况作出规定,使精神受害者得到应有的经济救济和补偿.     

文质彬彬,然后君子--评李文初教授《汉魏六朝文学研究》

相比于隋唐及其后的文学而言 ,汉魏六朝文学有其特殊性 ,其一 ,“文学”的概念由朦胧到清晰 ,但具体过程还需要论证 ;其二 ,汉魏六朝 80 0年间 ,各种学术思潮交杂其中 ,道教和佛教两大宗教也从诞生和传入到逐渐发展壮大 ,与文学的关系始终纠缠不清 ;其三 ,许多文体开始孕育并发展成熟 ,文体彼此之间往往有交互的关系 ,但由于资料的匮乏或残缺 ,若要对当时某种文体作深入的研究并不容易 ;其四 ,80 0年间战乱频仍 ,许多典籍遭到破坏 ,或毁于兵燹 ,或坏于人为 ,致使今天的研究常常遇到资料上的困难 ,地下实物也由于掘墓之风和魏晋六朝之薄葬而…