A direct comparison of physical block occupancy versus timed block occupancy in train timetabling formulations

Two fundamental mathematical formulations for railway timetabling are compared on a common set of sample problems, representing both multiple track high density services in Europe and single track bidirectional operations in North America. One formulation, ACP, enforces against conflicts by constraining time intervals between trains, while the other formulation, RCHF, monitors physical occupation of controlled track segments. The results demonstrate that both ACP and RCHF return comparable solutions in the aggregate, with some significant differences in select instances, and a pattern of significant differences in performance and constraint enforcement overall.     

An agent-based nurse rostering system under minimal staffing conditions

Nurse rostering is a complex problem. We propose a new heuristic using a competitive agent-based negotiation that focuses on nurse preferences called competitive nurse rostering (CNR). Unlike the existing literature, CNR models each nurse's preference functions separately and separates the cost minimization and preference maximization problems. CNR produces quality nurse rosters even though it cannot leverage extra staffing. As an agent system, CNR can distribute computational requirements over several computer systems, include other solution methods at various points in of the rostering problem, and act as a real-time scheduling system. These benefits are not naturally inherent in centralized heuristic solutions.     

Flexibility in the gig economy: managing time on three online piecework platforms

Gig economy platforms seem to provide extreme temporal flexibility to workers, giving them full control over how to spend each hour and minute of the day. What constraints do workers face when attempting to exercise this flexibility? We use 30 worker interviews and other data to compare three online piecework platforms with different histories and worker demographics: Mechanical Turk, MobileWorks, and CloudFactory. We find that structural constraints (availability of work and degree of worker dependence on the work) as well as cultural‐cognitive constraints (procrastination and presenteeism) limit worker control over scheduling in practice. The severity of these constraints varies significantly between platforms, the formally freest platform presenting the greatest structural and cultural‐cognitive constraints. We also find that workers have developed informal practices, tools, and communities to address these constraints. We conclude that focusing on outcomes rather than on worker control is a more fruitful way to assess flexible working arrangements.     

基于制造业转型下的多属性关联的产品服务方案决策研究

受当下企业产业链扩展的影响,制造业正处于转型升级的关键时期,服务型制造业已成为制造企业获取市场竞争优势的主要手段,主要为客户提供产品服务方案来满足客户个性化需求,产品模块与服务模块如何组成已成为决定服务型制造企业能否转型成功的关键所在。本文以产品服务系统方案的形成过程为基础,刻画了产品模块与服务模块的选取过程,基于Choquet积分算子构建了在产品服务属性相关联下的产品模块与服务模块的决策模型,并给出了相应求解方法,最后通过算例验证了该理论的实践性。研究结果表明:产品模块与服务模块属性的关联性有助于实施产品服务方案,解决客户问题。     

流水工序调度与生产效率的关系模型分析

提出一种基于粒子群算法的流水工序调度任务优化模型。利用流水工序调度任务的特点得到流水工序时间约束条件,利用粒子群算法的原理建立流水工序调度任务优化模型,利用粒子群算法对模型进行求解。仿真实验表明,利用该算法能够得到流水工序调度问题的最优解,提高生产效率。     

关于曲线积分和曲面积分教学中几个难点的突破

加强曲线、曲面积分概念讲解,标准化曲线、曲面积分的计算程序,沟通有关积分之间关系,以消除学生 对斯托克斯等公式的深奥感,有效地突破了曲线、曲面积分教学中的几个难点。     

对中期财务报告准则的几点思考

本就中期财务报告准则的有关问题进行了阐述，重点讨论了中期财务报告准则的制定背景、理论依据及启示等问题。章认为，中期财务报告准则的制定符合我国的客观实际，有助于提高上市公司会计信息质量，保护投资的利益。     

大跨度天基数据链的TDD时隙调度分析与优化

针对天基数据链系统卫星间的传播时延较大且节点间距离变化较大等特点,提出了一种提高时频资源利用率、提升系统容量、减小时延的方法。在时分多址与空分多址相结合的接入方式下,进行了时隙调度的分析与优化,利用卫星星座的空间复用与大跨度传播时延特性,采用时隙编排、收发状态调整、帧格式优化等手段,将信道利用率和系统容量提升了1倍,将卫星节点在某一方向获得服务的平均等待时间缩短为原来的1/4,提高了天基数据链系统的服务质量。     

三主桁连续钢桁拱桥整体节点有限元分析

东平水道桥是武广高速铁路上一座四线铁路桁架拱桥,主跨结构为99m+242m+99m的三主桁连续钢桁拱,主桁采用整体节点形式,三主桁内力分析表明中桁处受力最大。节点板联结着主桁、腹杆、横梁、平联等各类杆件,结构及受力均较复杂,节点应力分布是设计中的关键问题之一。文章利用有限元程序对其特殊位置节点板进行应力分析,研究了其应力分布及传力特性,为设计提供依据和给同类桥梁提供参考。研究表明通过调整节点构造和板件刚度,节点具有足够的受力与传力功能。     

保险合同解释方法研究

保险合同是保险人致力于合同订立和履行上的一致性,为自己易于计算、节约成本而创造出来的格式化合同。该合同使得保险人对其所承担的风险、责任、险种等等一目了然,有其存在的必要性。但是,导致了当事人双方谈判地位不平等,个别交涉成本过高,契约正义被隐藏等问题。因此,司法裁判成为声张契约正义以及维护当事人合法权益的迂回模式之一。然而,在审理案件中,对合同的进一步阐释、对双方当事人真实意思表示的探求以及对合同争议焦点的解决,都起着至关重要的作用。这就涉及到如何适用多种解释方式对该合同进行解释。