投入产出乘数的韩中比较:以产业关联模型的"一般关系"为中心

以韩国(1998年为准)与中国(1997年为准)的全国产业关联表为基本资料,对于产出物的"投入诱发系数矩阵"进行了新的推导.由此,对投入、雇佣及所得乘数进行了重新定义.本论文就是对乘数进行数量上的推算,进而对韩中两国进行比较与分析.     

Vendor Performance and Alternative Manufacturing Environments*

Today, many American firms are demanding a high level of performance from their major suppliers while at the same time reducing the number of them. Vendor performance is an important aspect of maintaining low production costs and high product quality. In this study, we examine the effects of poor vendor quality and vendor lead time uncertainty in a variety of manufacturing environments using a comprehensive simulation model. The results indicate that the effect of poor vendor performance on various manufacturing firms depends on the number of stocking points and the degree of component commonality. Moreover, disruption of the manufacturing system caused by poor vendor performance can be manifested in higher levels of inventory and order backlogs. We introduce the concept of supplyside uncertainty, as it relates to component-part commonality, to demonstrate that in certain environments commonality reduces order backlogs but increases total inventories and creates an environment that is very sensitive to vendor quality problems. Finally, several conjectures are posited for future research.     

An Integrative,Experiential Approach to Production Management Education

This paper addresses the important relationship between production and operations management (POM) and information technology. An approach to POM education is presented in which information technology is used to create an experiential learning environment that integrates the topics taught in POM courses. Results of an implementation of the proposed approach are presented and implications are discussed for POM education.     

A Comparative Analysis of Master Production Scheduling Techniques for Assemble-To-Order Products

This paper studies the master production scheduling (MPS) activity of manufacturing firms that produce assemble-to-order (ATO) products. It describes four techniques for master scheduling ATO products: end-product bills, modular bills, super bills, and percentage bills. These procedures are compared in terms of the percentage of customer orders delivered late, the mean tardiness of customer order deliveries, and the total cost of inventory using simulation analysis. The results indicate that the performance of an MPS technique is affected by the level of uncertainty of the end products' demands and the degree of component commonality in the product structure. In particular, modular bills produce the highest customer service level and super bills produce the lowest total inventory cost under most operating conditions. The conclusions also suggest that the choice of a particular MPS technique is often a compromise between the benefits of improved MPS performance and the costs of implementing and executing the MPS system.     

大学英语教学改革的路径思考

《大学英语课程教学要求》强调各高校根据本校的实际情况,针对大学英语教学现状,开展大学英语教学改革。因此,与时俱进,根据校情,推进大学英语教学改革是每位英语教育工作者思考的问题。对照《要求》,大学英语教学改革的路径主要包括营造英语学习有效环境、合理利用多媒体与网络教学手段、健全课程教学体系等。     

THE PERFORMANCE OF A SIMPLE INCREMENTAL LOT-SIZING RULE IN A MULTILEVEL INVENTORY ENVIRONMENT

A simple incremental cost approach to lot sizing was tested in a multilevel inventory environment. The incremental approach has not previously been tested in a large-scale study involving multiple product-structure levels. Using the Wagner-Whitin (WW) algorithm as a benchmark, the simple incremental rule (IPPA) was compared to three heuristic procedures (LFL, EOQ, and POQ) frequently used in material requirements planning (MRP) lot-sizing research. The incremental rule consistently generated lower total order/setup and carrying costs than the three heuristics across the 3,200 multilevel test situations examined. In many of the test situations, the incremental rule also outperformed the WW benchmark.     

COMMENTS ON “COST INCREASES DUE TO DEMAND UNCERTAINTY IN MRP LOT SIZING”: A VERIFICATION OF ORDERING PROBABILITIES

In a recent article in this journal, De Bodt and Van Wassenhove [1] presented analytic derivations related to lot-sizing behavior under uncertainty. Although their models appear to have been verified in the aggregate by simulation experiments, detailed justifications for several of the derivations are missing. The present paper looks at De Bodt and Van Wassenhove's analysis and provides verifications of (and corrections to) the ordering probabilities and order cycles used by the authors to estimate the cost effects of forecast errors in the particular operating environment studied. The probabilities simulated in this study also generate additional insight into the “system nervousness” caused by lot-sizing and forecast errors.     

公文主旨的形成与诉求要求

公文主旨是公文的灵魂。它的形成是客观现实与主观认识相统一的结晶。公文主旨诉求要求正确、鲜明、集中和深刻。因此,公文写作者竭力加强自身各方面的素养是关键。     

The Integration of Cost and Capacity Considerations in Material Requirements Planning Systems

Within the sequential framework of material requirements planning (MRP), a master production schedule (MPS) of end-item production is prepared and a bill-of-material processor is used to convert the MPS into a plan for needed subassemblies, parts, and materials. This study examines the impact of different procedures for considering inventory-related costs and capacity limitations in the two phases of planning: master production scheduling and bill-of-material (BOM) processing. A total of nine procedures are considered for integrating the two phases of planning. The results indicate that the integrated procedures have a significant effect on the trade-offs among inventory-related costs, work load variations, over/under time costs, and excess work loads. Further, the results suggest that the method used to develop the MPS has the primary influence on these trade-offs, but the method used by the BOM processor can sometimes have a moderating effect.     

新课程要求与大学英语阅读教学模式改革

以往的大学英语阅读教学以教师为中心,学生缺乏自主学习的意识和动力,不能运用英语知识进行有效交际。为了提高大学生的英语综合应用能力,必须对大学英语阅读教学模式进行改革。大学英语阅读教学改革有两个操作性模式:采用“标准练习”,培养学生独立阅读能力及英语综合应用能力;转变传统的阅读教学模式,由原来的呈现—操练—应用转变为自由交际—呈现—操练—真实交际,激发学生阅读兴趣并提高其听说能力。