Trade-off between quoted lead time and price

In a make-to-order environment, lead time and price can play a crucial role in determining the financial success of a firm. Their importance increases when demand is sensitive to the quoted lead time and price. A model is presented which uses the quoted lead time and price as a mechanism to determine the optimal demand level. The relationships between the model parameters and their impacts on the firm's profit is also analysed. In addition, the effect of the number of job requests, and the mean processing time are examined. Based on the results presented in this paper, there is clear indication that the firm's profit is sensitive to the inventory holding rate, and that the inventory holding cost component is redundant in the presence of a tardiness cost component.     

A Welcome to the International Statistical Conferences

Criteria for assessing the effectiveness of a medical screening program are difficult to define; medical knowledge and screening procedures change rapidly, and self-selection at medical screens is unavoidable. This article discusses these and other basic issues in evaluation of medical screening programs with particular reference to results from the HIP breast cancer study. In addition, the article reviews various statistical models that describe the processes of disease and screening. The models are shown to be statistically indistinguishable in practice because of the small sample sizes typically available in medical screening trials. Finally the article suggests incorporating knowledge from clinical trials and from studies of robustness into statistical models designed to identify reasonable strategies for screening.     

方波阳极溶出伏安法测定区分溶解态与胶体态铅

本文对在赤铁矿胶体存在下用方波阳极溶出伏安法测定区分溶解态和胶体态铅进行了研究。赤铁矿胶体的存在对铅离子的电化学测定没有影响。赤铁矿胶体存在时测得的铅峰电流随振荡时间、ｐＨ及加入铅浓度的变化与经典的通过分离固液相方法测得的铅在赤铁矿上的吸附动力学曲线、吸附ｐＨ曲线及吸附等温线的规律一致,峰电流反映的是溶液中铅离子的变化。赤铁矿胶体的铅滴定曲线类似于溶解配体的滴定曲线,因此可以利用电化学方法测定胶体的吸附容量     

服务水平约束下的建筑安装行业多仓库联合库存系统模型研究

本文针对建筑安装行业库存管理的特点,对其不同地点的多个仓库的库存方式进行综合分析,建立了服务水平约束下的建筑安装行业多仓库联合库存系统模型,给出了相应的数学模型与算法。通过算例验证表明,服务水平约束下的建筑安装行业多仓库联合库存系统模型可以有效降低建设项目的库存成本,对增加企业利润有着十分重要的现实意义。     

浅析《中国日报》英语纯新闻报道中导语的词汇特征

消息主要有标题,导语和正文三大部分组成。其中,导语是消息区别于其他文体的重要标志。它以简练而生动的文字表述新闻事件中的最重要的内容。本文借助语料库语言学的相关知识对新闻导语语料库进行了定性和定量分析,试图探究导语的词汇特征。     

大气中痕量镉、铅的测定

本文提出在0．05mol／LKCI－0．02mol／LHNO3－0．0025mol／L（CH2）5N4－3×10（－5）mol／LHgCl2体系中，采用微分脉冲阳极溶出伏安技术测定大气中痕量镉、铅，该方法灵敏度高，检测下限达5．0×10（-11）ug／ml（即0．05ppb），样品回收率均在95－105％范围内，十次平行测定结果的相对标准偏差不大于5％。     

The effect of MRP lot sizing on actual cumulative lead times in multi-level systems

This study investigates how different lot sizing techniques influence the cumulative lead time for multi-level production-inventory systems controlled by material requirements planning (MRP). Theoretical approaches, a numerical example, as well as simulation are used to analyse and illustrate the combined effect of lot sizing at different product structure levels. It is shown that lot-sizing requirements for more than a single period, such as fixed period requirements, period under quantity, Silver Meal algorithm, as well as economic order quantity will lead to longer actual cumulative lead times than would be expected, when taking the item lead times along the critical path through the product structure into account. Consequently, MRP will underestimate the cumulative lead time and will require a longer planning horizon. We show that the extension of the cumulative lead techniques covering the time is a lot-sizing related phenomenon and cannot be accounted for by, e.g. using safety lead time. Lot-sizing techniques with multi-period coverage will only occasionally provide the 'expected' cumulative lead time. We also show that average and maximum throughput times, as well as throughput time variability increases with increasing time-period coverage of lots.     

Supply chain management: A just-in-time perspective

Just-in-time (JIT) has been a widely recognized production philosophy alternative since the early 1980s. JIT principles and techniques have been widely adopted in many manufacturing firms. More recently, supply chain management has evolved as a discipline focusing on the design, planning and control of processes linking the initial raw materials to the ultimate consumption of the finished product. Supply chain efficiency is dependent on the efficiencies of the individual manufacturing organizations and the ability to connect along the supply chain. In this paper supply chain management from a JIT perspective is investigated, focusing on the linking mechanisms between successive companies and the collective efficiency of the supply chain.     

基于提前期的通用件库存模型研究

通用件正作为企业在市场上提供更高的产品多样化,而在企业内部保持零部件低多样化的优化技术而被广泛研究和应用。本文在考虑提前期影响的前提下,建立无通用件和有通用件的库存模型,并以风神汽车有限公司有关数据进行案例研究分析,通过数据分析揭示通用件应用的一些管理启示,并修正了一些理论界的原有观点。