大学生就业决定因素分析——基于多层模型的方法

本文利用山东2007届高校毕业生就业调查数据,建立多层交叉随机效应模型,检验了个体、专业和学校等多层变量对大学生就业的影响。结果发现,初次就业概率在学校和专业之间存在显著差异,且学校因素对就业的作用大于专业,但学校与专业对就业的交互作用不显著。就业能力以及与专业相关的实习经历对就业具有显著的正向作用。因此,大学生就业政策的重点是提高教育质量和突出专业特色,提升就业能力,完善就业导向的实习指导和服务。     

A statistical analysis of the screening measure of multiple recursive random number generators of orders one and two

This paper presents the results of a comprehensive empirical analysis of the screening measure of multiple recursive generators (MRGs) of orders one and two. Two kinds of screening measures are distinguished: spectral test and lattice test. With regard to these screening measures, two exhaustive searches of the twenty best MRGs of orders one and two are conducted. Some empirical comparisons reveal that the screening procedure with maximum spectral value criterion is preferred in terms of efficiency and thus, is a good way of obtaining ideal MRGs of higher orders. Several extensively tested second-order MRGs are also presented and are therefore recommended.     

关于《中华人民共和国森林法》立法技术的若干探讨——以第一次征求意见稿为例

《中华人民共和国森林法》是森林保护、森林建设领域的基本法律,科学完善的森林法是保护森林资源、促进林业可持续发展的法律基础。《中华人民共和国森林法》修改草稿第一次征求意见稿已经公布,意见稿的制订总体上是成功的,吸收了近年来森林法理论研究的成果以及一些成功的实践经验。但是对征求意见稿的立法技术进行分析后可以得出结论,草稿在立法技术上还存在着若干缺陷。     

林权改革的宪法学思考

2008年6月8日《中共中央国务院关于全面推进集体林权制度改革的意见》公布,引发了新阶段的集体林产权制度改革。从宪法学角度对其进行分析,一方面林权改革过程中＂林＂本身涉及到森林、林木和林地的所有权和使用权问题,这关涉到《宪法》第9条森林资源权利问题和《宪法》第10条土地制度问题。另一方面,林权改革是以政府主导型模式进行推进,主要在中共中央国务院的决定、意见等规范性文件指导下进行,而对制定这些规范性文件的政府权力行使的合宪性考察也是本文关注的重点。     

Hypothesis group testing for disjoint pairs

Classical group testing (CGT) is a widely applicable biotechnical technique used to identify a small number of distinguished objects from a population when the presence of any one of these distinguished objects among a group of others produces an observable result. This paper discusses a variant of CGT called group testing for disjoint pairs (GTAP). The difference between the two is that in GTDP, the distinguished items are pairs from, not individual objects in, the population. There are several biological examples of when this abstract model applies. One biological example is DNA hybridization. The presence of pairs of hybridized DNA strands can be detected in a pool of DNA strands. Another situation is the detection of binding interactions between prey and bait proteins. This paper gives a random pooling method, similar in spirit to hypothesis testing, which identifies pairs of objects from a population that collectively have an observable function. This method is simply to apply, achieves good results, is amenable to automation and can be easily modified to compensate for testing errors. M.A. Bishop is supported by AFOSR FA8750-06-C-0007. A.J. Macula is supported by NSF-0436298, AFOSR FA8750-06-C-0007.     

Estimation for the censored partially linear quantile regression models

In this article, we develop estimation procedures for partially linear quantile regression models, where some of the responses are censored by another random variable. The nonparametric function is estimated by basis function approximations. The estimation procedure is easy to implement through existing weighted quantile regression, and it requires no specification of the error distributions. We show the large-sample properties of the resulting estimates, the proposed estimator of the regression parameter is root-n consistent and asymptotically normal and the estimator of the functional component achieves the optimal convergence rate of the nonparametric function. The proposed method is studied via simulations and illustrated with the analysis of a primary biliary cirrhosis (BPC) data.     

A bivariate distribution with Lomax and geometric margins

We develop a stochastic model describing the joint distribution of $(X,N)$, where $N$ has a geometric distribution while $X$ is the sum of $N$ dependent, heavy-tail Pareto components. Models of this form arise in many applications, ranging from hydro-climatology to finance and insurance. We present fundamental properties of this vector, including marginal and conditional distributions, moments, representations, and parameter estimation. We also include an example from finance, illustrating modeling potential of this new bivariate distribution.     

A new way of quantifying the symmetry of a random variable: Estimation and hypothesis testing

New measures of skewness for real-valued random variables are proposed. The measures are based on a functional representation of real-valued random variables. Specifically, the expected value of the transformed random variable can be used to characterize the distribution of the original variable. Firstly, estimators of the proposed skewness measures are analyzed. Secondly, asymptotic tests for symmetry are developed. The tests are consistent for both discrete and continuous distributions. Bootstrap versions improving the empirical results for moderated and small samples are provided. Some simulations illustrate the performance of the tests in comparison to other methods. The results show that our procedures are competitive and have some practical advantages.     

A note on the random yield from the perspective of the supply chain

Keren [The single-period inventory problem: extension to random yield from the perspective of the supply chain. Omega 2009;37:801-10] considers a supply chain in which the distributor faces a known demand and orders from the producer subject to a random production yield, and shows that the distributor may find it optimal to order more than what is needed due to supply uncertainty under a uniform distribution. However, Keren (2009) does not address the questions whether it is always optimal for the distributor to order more, or when to order more. In this note, we point out that ordering more is not always an optimal strategy and specify the condition under which this strategy becomes optimal. We also examine the profit losses of the supply chain members resulting from the random yield supply, which is another question not considered in Keren (2009). The producer is found to possibly benefit from this production yield uncertainty, although the performances of the distributor and of the entire supply chain are always undermined. Our results are obtained under a more generalized yield distribution, and can thus be applied to wider industrial domains.