Measuring efficiency with products,by-products and parent-offspring relations: A conditional two-stage DEA model

In the usual data envelopment analysis (DEA) setting, as pioneered by Charnes et al. (1978) [1], it is assumed that a set of decision making units (DMUs) is to be evaluated in terms of their relative efficiencies in converting a bundle of inputs into a bundle of outputs. The usual assumption in DEA is that each output is impacted by each and every member of the input set. One particular area of recent research is that relating to partial input to output impacts where the main issue addressed is that in many settings not all inputs impact all outputs. In that situation the authors view the DMU as consisting of a set of mutually exclusive subunits, with each subunit having its own unique bundle of inputs and outputs. Examined as well in this area, is the presence of multiple processes for generating sets of outputs. Missing from that earlier work is consideration of the presence of outputs in the form of by-products, giving rise to a parent-offspring phenomenon. One of the modeling complications there is that the parent assumes two different roles; as an input affecting the offspring, while at the same time being the dominant output. This gives rise to a model that we refer to as conditional two-stage. Another complication is that in the presence of multiple processes, by-products often arise out of only a subset of those processes. In the current paper we develop a DEA-type of methodology to handle partial input to output impacts in the presence of by-products.     

多源高维数据的多分类纵向整合分析及应用

多分类数据分析在实证研究中具有重要意义。然而,由于高维数、小样本及低信噪比等原因,现有的多分类方法仍面临信息量不足而导致的效果不佳问题。为此,学者们通过收集更多信息源 数据以更全面地刻画实际问题。不同于收集相同自变量的不同源样本,目前较为流行的多源数据收集了相同样本的不同源自变量,它们的独立性和相关性为统计建模带来了新的挑战。本文提出基于典型变量回归的多分类纵向整合分析方法,其中利用惩罚技术实现变量选择,并独特地考虑不同源数据间的关联结构,提出高效的ADMM算法进行模型优化。数值模拟结果表明,该方法在变量选择和分类预测 上均具有优越性。基于我国上证50的多源股票数据,利用该方法对2019年股票日收益率的影响因素进行了实证探究。研究表明,本文提出的多分类整合分析在筛选出具有解释意义变量的同时具有更好的预测效果。     

Storage constrained vendor managed inventory models with unequal shipment frequencies

We consider a supply chain where a vendor manages its multiple retailers' stocks under a vendor managed inventory (VMI) contract that specifies upper stock limits at the retailers' premises and overstock costs for exceeding those limits. We formulate a mixed integer nonlinear program that minimizes total supply chain costs and allows unequal shipment frequencies to the retailers. We develop an algorithm to solve its relaxed version which provides a lower bound cost solution. We propose a cost efficient heuristic procedure to generate delivery schedules to the retailers. We conduct a sensitivity analysis to provide insights on the performance of the proposed heuristic. Results show that our heuristic finds optimal or near optimal solutions, and it proposes substantial savings compared to the total supply-chain cost in the cases where there is no VMI and where there is VMI but with equal shipment frequencies to retailers.     

新媒体发展背景下的教育政策变迁及其多源流分析——以学前教育政策为例

我国学前教育政策资源配置调整变化的关键时期也是新媒体发展的黄金时期。以学前教育政策变迁为例，采用多源流理论探讨新媒体对学前教育政策变迁影响的逻辑。分析发现，新媒体对学前教育政策变迁的影响方式主要有：在问题源流上，通过提出和解释关键指标、强化焦点事件的影响以及促进问题反馈等方式影响政策制定过程；在政策源流上，通过促进形成政策原汤，促进官方与非官方的对话等方式影响议程；在政治源流上，主要有激发国民情绪、表明政府态度及理念等方式。三种源流耦合、交互作用，并在特定政策之窗打开时，共同促成学前教育政策的制定。     

A Simulation Study Comparing Multiple Imputation Methods for Incomplete Longitudinal Ordinal Data

Multiple imputation (MI) is now a reference solution for handling missing data. The default method for MI is the Multivariate Normal Imputation (MNI) algorithm that is based on the multivariate normal distribution. In the presence of longitudinal ordinal missing data, where the Gaussian assumption is no longer valid, application of the MNI method is questionable. This simulation study compares the performance of the MNI and ordinal imputation regression model for incomplete longitudinal ordinal data for situations covering various numbers of categories of the ordinal outcome, time occasions, sample sizes, rates of missingness, well-balanced, and skewed data.     

管理层股权激励引发盈余管理的实证研究

本文从盈余管理的角度出发，选取截止至2007年12月已经实施股权激励的48家上市公司中的40家为样本，借鉴国外相关资料，运用管理层授予股权激励与其年薪金额的比例来考察股权激励程度，在扩展的Jones模型的基础上加入费用项目后来估计企业盈余管理程度，建立多元回归模型，实证检验了在我国实施管理层股权激励与企业盈余管理行为间存在着正相关关系，有必要进一步加强对股权激励实施过程的监管。     

“多元素养作文”初探

"多元素养作文"是在对作文教学现状反思以及对作文、作文教学再认识的基础上提出的作文课程设想.它是由"一向三维四元"构成的;其基本理念有目标理念、训练理念、资源理念;基本特征是训练的系统性、资源的开放性、形式的自主探究、过程的体验性、操作的互动性;它的训练体例由作文境域、个性体悟、路径辨析、创新呈现、反思交流组成.     

Quantitative refinements for comparisons of institutional performance

In the context of the data and issues discussed by Goldstein and Spiegelhalter, we suggest refinements which can be used by decision makers when confronted with ranking problems associated with 'league tables'. Two ranking criteria are defined and their performance illustrated for one of the studies reported by Goldstein and Spiegelhalter.     

Issues in the design and analysis of therapeutic trials in human immunodeficiency virus infection

The first randomized trial of antiviral therapy in human immunodeficiency virus (HIV) disease included 282 patients with acquired immune deficiency syndrome (AIDS) or AIDS-related complex and was stopped in 1986 after an average follow-up of 4 months because of a substantial reduction in mortality in the group who received zidovudine (AZT). The era of anti-HIV treatment had begun. This paper discusses some of the difficulties which have emerged over the subsequent 10 years as new anti-HIV drugs have been developed requiring evaluation in clinical trials. The trials in which the British Medical Research Council has played a major role (the Concorde, Alpha and Delta trials) and some of the key trials conducted by the AIDS Clinical Trials Group (ACTG) (the ACTG 019 and ACTG 175 trials) and the Community Programs for Clinical Research on AIDS (CPCRA) (the CPCRA 007 trial) in the US will be used to illustrate some of the issues faced by clinical trialists and governmental regulatory agencies in the evaluation of therapies for a disease which, in spite of advances in therapy, still has a high mortality.     

Finding Jack Michael’s Footprints in the Sand

Jack Michael left a legacy of fine discriminations among technical terms, a careful parsing of theoretical concepts, and a variety of behavioral interpretations of complex behavioral phenomena. When pushing into relatively unfamiliar territory in areas such as “memory,” automatic reinforcement, multiple control, and additivity of response strength, I have been surprised and delighted to find evidence that Jack had once explored the same topics, in the same way, and had come to the same conclusions toward which I was groping.