第二单元对话及阅读.doc

阅读：Supplementary ReadingFor most marketing or logistics applications，a small percentage of the entities(e.g. products,markets,orders,or suppliers) account for a large percentage of the volume (such as sales). This is often called the 80/20 rule,or Paretos law. The 80/20 rule, based on extensive observation in industry, states that for an average enterprise 80 percen of thd sales volume is typically accounted for by 20 percent of the products .A corollary to thd rule is that 80 percent of enterprise sales are accounted for by 20 percent of the customers. The reverse perspective of the rule would state that the remaining 20 percent of sales are obtained from 80 percent of the products, customers, etc. in general term, the 80/20 rule implies that a majority of sales volume results from relatively few products or customes.The 80-20CurveDo you think a warehouse manager will give equal space to every kind of products ? Give your reasons .(Excerpts from Business Logistics Management by Ronald. H. Ballous, lightly abridged.It is reasonably expected that the volumes of cargo flow in any given firm vary depending on how successful their sales are. At any point in time, there exists a product phenomenon called the 80-20 curve, a particularly valuable concept for logistics planning This concept is derived from the fact that the bulk of the sales are generated from relatively few products in the product line. This simply means 80 percent of a firms sales are generated by 20 percent of the product line items. An exact 80-20 ratio is rarely observed,but the disproportionality between sales and the number of items is generally true. Toillustrate,consider 14 products of a small chemical company .These products are ranked according to their sales volume,as shown in Table 1. A cumulative percentage of total dollar sales and of total number of items is computed. These percentages are then plotted,as in Figure1. which shows the characteristic 80-20 curve. However,in this particular case, about 35 percent of the items account for 80 percent of the salse. The 80-20 concept is particularly useful in distribution planning when the products are grouped or classified by their sales activity. The top 20 percent might be called A items,the next 30 percent B items, and the remainder C items. Each category of items could be distributed differently. For example, A items might receive wide geographic distribution through many warhouses with high levels of stock availability, whereas C items might be distributed from a single , central stocking pint (e.g. a plant) with lower total stocking levels than for the A items. B items would have an intermediate distribution strategy where few regional warehouses are used. Another frequent use of the 80-20 concept and an ABC classification is to group the products in a warehouse,or other stocking point, in a limited number of categories where they are then managed with different levels of stock availability. The product classifications are arbitrary. The point is that not all product items should receive equal logistics treatment. The 80-20 concept with a resulting product classification provides a scheme,based on sales activity, to determine which products will receive various levels of logistics treatment. For analytical purposes, it is useful to describe the 80-20 curve mathematicall. Although a number of mathematica equations might be used, the following relationship has been suggested;Where the relationship between Y and X is known, for example, if 25 percent of the items represent 70 percent of the sales then, from Equation