A Flexible Evaluative Framework for Order Picking Systems

This paper develops a novel framework to evaluate the integral performance of order picking systems with different combinations of storage and order picking policies. The warehousing literature on order picking mostly considers minimizing either elapsed time or distance as the sole objective, whereas warehouse managers in a supply chain have to look beyond single‐dimensional performance and consider trade‐offs among different criteria. Thus managers still need a unified and efficient framework to select a portfolio of appropriate order picking policies from a multi‐criteria and contextual perspective. Our framework—combining data envelopment analysis, ranking and selection, and multiple comparisons—provides an efficient methodology to simultaneously analyze several interrelated problems in order picking systems with multiple performance attributes, such as service levels and operational costs. We demonstrate our approach through comprehensive evaluations of order picking policies in three low‐level, picker‐to‐parts rectangular warehouses facing demand variations.     

需求分布规律变化情况下的报童订货策略

在需求分布规律变化情况下,报童在进行订货决策时会因为错误判断需求分布规律而导致期望库存成本增加。为了解决这一问题,本文集成传统历史需求信息和非传统需求信息以正确地认知需求分布规律,在此基础上决策订货量。假设需求服从均值不同、方差相同的两种类型的正态分布,每一种正态分布的概率已知。利用信号检测理论构建基于历史需求信息与需求分布概率的报童最优订货策略,并与只基于需求分布概率的直觉规则订货策略进行对比。结果表明：只要排除需求分布概率很大或很小两种极端情况,最优订货策略比直觉规则订货策略在控制期望库存成本方面的作用更明显,即利用历史需求信息可以有效修正报童对实际需求分布的检测结果,从而提高实际订货决策的准确性。研究结果对传统历史需求信息和非传统需求信息的集成以及需求信息交换等有一定的管理学启示和应用价值。     

From design to operations: a process management life-cycle performance measurement system for Public-Private Partnerships

Public–Private Partnerships (PPPs) have become a critical vehicle for delivering infrastructure worldwide. Yet, the use of such a procurement strategy has received considerable criticism, as they have been prone to experiencing time/cost overruns and during their operation poorly managed. A key issue contributing to the poor performance of PPPs is the paucity of an effective and comprehensive performance measurement system. There has been a tendency for the performance of PPPs to be measured based on their ex-post criteria of time, cost and quality. Such criteria do not accommodate the complexities and lifecycle of an asset. In addressing this problem, the methodology of sequential triangulation is used to develop and examine the effectiveness of a ‘Process Management Life Cycle Performance Measurement System’. The research provides public authorities and private-sector entities embarking on PPPs with a robust mechanism to effectively measure, control and manage their projects’ life cycle performances, ensuring the assets are ‘future proofed’.     

On pooling data summaries in the absence of interactions “response-by-study”

The standard hypothesis testing procedure in meta-analysis (or multi-center clinical trials) in the absence of treatment-by-center interaction relies on approximating the null distribution of the standard test statistic by a standard normal distribution. For relatively small sample sizes, the standard procedure has been shown by various authors to have poor control of the type I error probability, leading to too many liberal decisions. In this article, two test procedures are proposed, which rely on thet—distribution as the reference distribution. A simulation study indicates that the proposed procedures attain significance levels closer to the nominal level compared with the standard procedure.     

无权处分合同的当事人分析

无处分权人和相对人是无权处分合同的基本当事人,但由于处分财产属于权利人,因此权利人在无权处分合同中的地位还需进一步明确,笔者结合《合同法》第51条的规定,并区分无权处分合同最终结局的不同情形来分析无权处分合同的当事人。由于权利人与所处分财产的权属关系,如果权利人追认无权处分合同,那么结合笔者的＂新并存债务承担＂理论,应当允许权利人作为无权处分合同的浮动当事人。     

基于Vague交叉熵的Topsis产品方案优选方法

产品的设计方案优选是个复杂的多准则团队协同决策过程。为解决产品设计方案优选中多准则间的关联被忽视的问题,提出一种改进的Topsis方法模型,即通过Vague交叉熵建立起多准则下的单个专家评价结果模型,再应用证据推理理论融合各专家的冲突性的评价结果,得到各方案综合评价值,以判断出优解顺序。最后,以共享底盘开发的方案评价与选择作为实例验证了该方法的可行性与有效性。     

山水画在五代两宋勃兴探因

任何艺术的成熟、繁荣决不是单个因素的作用,而是那个时代甚至相承续的几个时代的各种因素共同整合的结果.山水画萌生于魏晋南北朝而空前繁盛于五代两宋,其原因主要是大唐文化的影响、五代两宋的疲软分裂的时局、文人画士的自觉追求.     

集成运放实验中的异常现象及分析

阐述了集成运放实验中的一些异常现象,分析了产生这些异常现象的原因,并提出了相应的解决办法。     

矩阵算子代数上的完全正映射

证明了二阶矩阵 C* 代数之间 *同构在满足辛群作用不变性时可表示为 C* 代数间的两个 *同构的直和 ,同时给出了矩阵 C*代数的一些类似数值矩阵的性质 .通过证明完全正映射的一个类似于 Krein- Milman定理的性质 ,给出了一个纯的完全正映射延拓的存在性证明 .