自动化立体仓库中出入库任务顺序与出库位置选择集成优化研究

具有多个出口的自动化立体仓库系统是一种将存储和分拣相结合的新型仓储技术,其最典型的特征是在货架底层有很多个出库位置以供取货人员分拣。研究此系统中出入库任务排序与出口选择的集成优化问题,以最小化堆垛机完成所有任务的移动距离为目标,将此问题转化为一个混合整数规划模型。根据问题的特点设计了两阶段启发式算法求解此问题,数值结果表明设计的算法能在较短时间内给出近似最优解,同时与企业常用的先到先服务方法相比,该算法可以缩短超过20%的移动距离。     

公司治理对会计信息披露质量影响 ——基于我国生物医药业上市公司的实证研究

会计信息披露是企业向信息使用者揭示和反映企业价值运动,高质量的信息披露可以降低信息不对称程度,使投资者能更正确地做出判断.以生物医药业上市公司为例,采用Logistic回归分析方法,系统研究公司治理与会计信息的披露质量之间的关系,发现公司治理中的董事会规模、独立董事比例和监事会规模的提高会使得会计信息披露质量得到提高,董事会会议次数与会计信息披露质量显著负相关.     

基于序化机理的稳健型股票价值投资决策——一个研究框架

面对资本市场风险加剧的现实背景,以"公司经营业绩与股票市场业绩一致趋优"为稳健型投资的核心要素,立足于区间数据表示、会计信息度量两个关键要素,开展稳健型股票价值投资的多准则决策建模研究。面向稳健型投资决策目标,提出满足"稳健性""局部性""全局性"3个特性的序化机理,围绕关键特征选择、特征评价、全序化建模的主体脉络建立系统性多准则决策方法,进而构建"稳健型股票价值投资决策"的研究框架。     

我国环境多元治理模式法律保障机制探究

未清晰地认识和定位政府、企业、社会公众三者的关系,未处理好三者的分工与衔接,是造成我国环境多元治理模式难以落实的关键问题。究其主要原因在于过分依赖传统政府管制模式的路径,以致政府在环境治理中起主导作用而轻视企业、社会公众作为治理主体的力量,导致其他治理主体参与环境治理法律机制的缺失。比较分析三者存在的障碍,提出落实环境多元治理模式法律保障的建议,从而构建起三者相互协作、共同治理环境的新局面。     

Collective versus Individual Effects in Survival Analysis of Multiple Failures

In survival analysis, we sometimes encounter data with multiple censored outcomes. Under certain scenarios, partial or even all covariates have ‘similar’ relative risks on the multiple outcomes in the Cox regression analysis. The similarity in covariate effects can be quantified using the proportionality of regression coefficients. Identifying the proportionality structure, or equivalently whether covariates have individual or collective effects, may have important scientific implications. In addition, it can lead to a smaller set of unknown parameters, which in turn results in more accurate estimation. In this article, we develop a novel approach for identifying the proportionality structure. Simulation shows the satisfactory performance of the proposed approach and its advantage over estimation under no assumed structure. We analyse three datasets to demonstrate the practical application of the proposed approach.     

A Rejection Principle for Sequential Tests of Multiple Hypotheses Controlling Familywise Error Rates

We present a unifying approach to multiple testing procedures for sequential (or streaming) data by giving sufficient conditions for a sequential multiple testing procedure to control the familywise error rate (FWER). Together, we call these conditions a ‘rejection principle for sequential tests’, which we then apply to some existing sequential multiple testing procedures to give simplified understanding of their FWER control. Next, the principle is applied to derive two new sequential multiple testing procedures with provable FWER control, one for testing hypotheses in order and another for closed testing. Examples of these new procedures are given by applying them to a chromosome aberration data set and finding the maximum safe dose of a treatment.     

Combining Inverse Probability Weighting and Multiple Imputation to Improve Robustness of Estimation

Inverse probability weighting (IPW) and multiple imputation are two widely adopted approaches dealing with missing data. The former models the selection probability, and the latter models data distribution. Consistent estimation requires correct specification of corresponding models. Although the augmented IPW method provides an extra layer of protection on consistency, it is usually not sufficient in practice as the true data‐generating process is unknown. This paper proposes a method combining the two approaches in the same spirit of calibration in sampling survey literature. Multiple models for both the selection probability and data distribution can be simultaneously accounted for, and the resulting estimator is consistent if any model is correctly specified. The proposed method is within the framework of estimating equations and is general enough to cover regression analysis with missing outcomes and/or missing covariates. Results on both theoretical and numerical investigation are provided.     

1980年代“译介热”与中国审美话语的本体自律

20世纪80年代的“译介热”通过引进西方现代文论资源,实现了对政治意识形态“工具论”“反映论”的反拨与对抗,与此同构的是审美自律的进程和审美本体的建构.“审美自律论”和“方法多元论”成为“译介热”的两个主要支点,共同参与现代性人学启蒙,促使了现代派文学的文本发现与形式自律.“审美自律论”促使了审美活动从外部的“他律”转向了审美的“自律”,形式主义文论、结构主义文论等在译介热中引入中国,纷纷促使了美学和文学批评从外部转向内部、从内容转向形式、从思想内涵转向话语革命.同时也直接启发了中国现代派文学和先锋小说的创作,激活了新时期以来潜藏的“形式化”冲动,从而使得形式和语言实验在80年代中后期的文学创作中焕发出愈加重要的作用.     

农民工城市融入的组织化实践

不同于既有农民工城市融入研究中的宏观制度主义视角,也区别于单一组织微观实践路径的研究取向,文章基于粤南沙镇的实地调研经验,总结提炼出“半正式组织”这一新型实践类型,有助于弥合既有研究中的宏观与微观鸿沟。“半正式组织”是对现代组织“正式与非正式”二元对立框架的尝试性超越,在组织结构、成员关系、资源链接方式等方面均呈现新特征,其形成机制可概括为党建引领、组织挂靠与领袖吸纳。“半正式组织”的实践功效表现为助推农民工在流入地提升经济机会,增强政治参与,链接公共服务,扩展群体社会交往,因而成为现阶段有限制度供给和市民化成本分摊机制不均衡情境下,实现农民工城市融入的新路径。     

信任对农民创业机会识别的影响

基于信任视角,构建农民创业者信任对创业机会识别的理论分析框架,运用链式多重中介方法,对浙江、安徽、河南和陕西4省880份农民创业者访谈数据进行实证分析,结果发现:信任能显著提高农民创业机会识别;农民创业者信任能通过外部知识获取与创业警觉性对创业机会识别产生间接影响,其作用路径有三条:外部知识获取的部分中介作用、创业警觉性的部分中介作用及外部知识获取与创业警觉性的链式中介作用。因此,政府应完善农民创业相关规章与制度;推进农村文化建设,提高信任水平;增加农民创业知识与技能的供给,培养农民创业者的机会警觉性。