Maximizing Throughput of Bucket Brigades on Discrete Work Stations

One way to coordinate workers along an assembly line that has fewer workers than work stations is to form a bucket brigade. The throughput of a bucket brigade on discrete work stations may be compromised due to blocking even if workers are sequenced from slowest to fastest. For a given work distribution on the stations we find policies that maximize the throughput of the line. When workers have very different production rates, fully cross‐training the workers and sequencing them from slowest to fastest is almost always the best policy. This policy outperforms other policies for most work distributions except for some cases in which limiting the work zones of workers produces higher throughput. In environments where the work can be adjusted across stations, we identify conditions for a line to prevent blocking.     

用等效外径法对塔式钻具组合防斜问题探讨

针对气体钻垂直井中塔式钻具组合防斜效果具有不确定性,在三弯矩方程的基础上,提出等效外径法对不等截面的塔式钻具进行力学特性研究,以等效外径法计算为依据,开发了简易的VB程序实现塔式钻具组合的力学分析以及对钻具组合优化设计和钻井参数调整,同时用ANSYS有限元软件二次开发ADPL语言编程实现塔式钻具组合侧向力的计算,这样不仅可以得到等效外径法计算的钻具侧向力大小,也可以得到有限元软件计算出的侧向力数据,并进行两种结果的对比分析。通过实例分析,所编写的VB程序能得到比较准确而且高精度的计算结果,同时探讨了影响钻具防斜效果的原因和改进方案。     

郑西客运专线无砟轨道铺设施工测量技术

随着我国铁路客运专线和高速铁路的发展,无砟轨道铺设施工技术得到应用。高速铁路对无砟轨道铺设施工提出了严格的限制,要求无砟轨道具有可靠的稳定性和高精度平顺性。就无砟轨道铺设施工测量技术,利用三维绝对位置坐标有效控制平顺度进行论述,为保证无砟轨道的安全施工提供参考和借鉴。     

基于Benford法则的M_2统计数据准确性研究

根据Benford法则,在样本量充足的情况下,统计数据的首位数字分布概率符合对数规律,而人为地捏造、篡改或者修饰数据将会破坏这种规律。将Benford法则引入到统计数据的准确性检验中,运用非参数统计中的χ2拟合优度检验,对中国人民银行官方网站所公布的1994年10月至2009年9月M2统计数据的准确性进行研究,结果表明：数据较好地符合了Benford法则,准确性较高。     

对制图课程和国标中几个相关问题的探讨

根据画法几何学和制图国家标准,对组合体三视图的称谓、视图概念及其与其他表达形式的关系等问题进行了探讨。分析了课程中视图含义前后存在的差异以及国标对视图赋予的两层意义,指出了由此带来的问题,进而提出停止使用三视图称谓以及增加外形视图名称和条文的建议。     

词块与英语专业学生写作质量的相关性研究

以湖北工业大学英语专业三年级学生的62篇习作为语料进行定量分析,试图探究英语专业学生的词块能力与其写作水平之间的相关性。分析结果显示：词块的正确使用与学生的写作质量显著相关,但每类词块与写作质量的相关系数不同。甸子构建者和短语搭配与学生写作质量高度相关;其次是多字短语;而约定俗成的表达法和限制性短语则与学生的写作质量未见明显相关性。     

Exact confidence interval estimation for the difference in diagnostic accuracy with three ordinal diagnostic groups

In the cases with three ordinal diagnostic groups, the important measures of diagnostic accuracy are the volume under surface (VUS) and the partial volume under surface (PVUS) which are the extended forms of the area under curve (AUC) and the partial area under curve (PAUC). This article addresses confidence interval estimation of the difference in paired VUS s and the difference in paired PVUS s. To focus especially on studies with small to moderate sample sizes, we propose an approach based on the concepts of generalized inference. A Monte Carlo study demonstrates that the proposed approach generally can provide confidence intervals with reasonable coverage probabilities even at small sample sizes. The proposed approach is compared to a parametric bootstrap approach and a large sample approach through simulation. Finally, the proposed approach is illustrated via an application to a data set of blood test results of anemia patients.     

Revenue‐Sharing vs. Wholesale‐Price Contracts in Assembly Systems with Random Demand

Assembly and kitting operations, as well as jointly sold products, are rather basic yet intriguing A decentralized supply chains, where achieving coordination through appropriate incentives is very important, especially when demand is uncertain. We investigate two very distinct types of arrangements between an assembler/retailer and its suppliers. One scheme is a vendor‐managed inventory with revenue sharing, and the other a wholesale‐price driven contract. In the VMI case, each supplier faces strategic uncertainty as to the amounts of components, which need to be mated with its own, that other suppliers will deliver. We explore the resulting components' delivery quantities equilibrium in this decentralized supply chain and its implications for participants' and system's expected profits. We derive the revenue shares the assembler should select in order to maximize its own profits. We then explore a revenue‐plus‐surplus‐subsidy incentive scheme, where, in addition to a share of revenue, the assembler also provides a subsidy to component suppliers for their unsold components. We show that, by using this two‐parameter contract, the assembler can achieve channel coordination and increase the profits of all parties involved. We then explore a wholesale‐price‐driven scheme, both as a single lever and in combination with buybacks. The channel performance of a wholesale‐price‐only scheme is shown to degrade with the number of suppliers, which is not the case with a revenue‐share‐only contract.     

准时生产方式下混流装配线的调度问题

混流装配线的调度问题是 JIT生产方式中的一个重要问题 .本文建立了多级混流装配线的调度模型 ,其目标是使不同生产级上各零部件的消耗量尽可能保持均匀 ,并用遗传算法和模拟退火进行求解 .试验表明 :遗传算法和模拟退火算法的求解质量比“目标追随法”有所提高     

A note on the two-sample mean problem based on jackknife empirical likelihood

In this article, we employ the jackknife empirical likelihood (JEL) method to construct the confidence regions for the difference of the means of two d-dimensional samples. Compared with traditional EL for the two-sample mean problem, JEL is extremely simpler to use in practice and is more effective in computing. Based on the JEL ratio test, a version of Wilks’ theorem is developed. Furthermore, to improve the coverage accuracy of confidence regions, a Bartlett correction is applied. The effectiveness of the proposed method is demonstrated by a simulation study and a real data analysis.