【正文】 al inventory control (SIC). After the description of Material Requirements Planning (MRP I), Manufacturing Resources Planning (MRP II), Distribution Resources Planning (DRP) and Enterprise Resources Planning (ERP), this paragraph will end with a short description of APS. Statistical inventory controlSIC is static in nature and operates solely on the basis of a predicted forecast. This method of inventory management employs a number of mathematical techniques to control inventories, based on historical turnover data. This method of inventory management is easy to puterise. Material Requirements PlanningThe puterised dataprocessing techniques introduced in enterprises from 1950 made it possible to perform plex calculations and to process large amounts of data. In this period MRP I systems were developed. For the first time the factor 180。time180。 made its entry into inventory management. MRP I systems operate on the basic of the existence of socalled dependent demand that can be calculated from a requirement for a product with an independent, predictable demand and the factor time in controlling inventories.MRP I prises a number of informationscience techniques to plan material acquisition (the inflow of the necessary raw and auxiliary materials and semimanufactures) and the production process on the basis of an established production plan for end products. A production plan is determined on the basis of market and turnover expectations. The position of each product in terms of ponents (raw materials, auxiliary materials and semimanufactures) is known and set out in a bill of material.Given an established production program for a specific period, the planner uses MRP I to calculate which ponents are required in what quantities and at what point in time, by examining the throughput time or delivery time of the ponent (scheduling).10 / 72 Manufacturing Resources PlanningMRP II is an extension of MRP I, which assumes unlimited capacity. The extension to MRP II involved the calculation of the required capacity. On the basis of a required production program, MRP II calculates back from the delivery data to determine what capacity is required in what quantity and at what point in time in order to deliver the orders punctually. It is important to know at an early stage which capacity element in the process (machine, people, money, supplier, etc.) will constitute the bottleneck and when. Distribution Resources PlanningA distribution work consists for the most part of several consecutive inventory points。 for example the factory, a central distribution centre (DC) and national sales warehouses. In a distribution work, coordination of the various activities (sales forecast, orders, transport and inventories) is essential. The principles of MRP I/II (dependent demand and scheduling) are also used in inventory management in distribution works: DRP.DRP is an information system that supports coordination within the distribution work. The purpose of such a system is to record goods flows and it requires that information must be available on where stocks are held, which goods are in transit and what are the changes in inventories. DRP makes it possible to coordinate the decisions taken at various point in the distribution work. Enterprise Resources PlanningERP is defined as a software architecture that facilitates the flow of information between all functions within a pany such as manufacturing, logistics, finance and human resources (Hicks, 1997). It is an enterprisewide information system solution (Lieber, 1995). An enterprisewide database, operating on a mon platform, interacts with an integrated set of applications, consolidating all business operations in a single puting environment (Peoplesoft, 1997). Ideally, the goal of an ERP system is to be able to have information entered into the puter system once and only once (Lieber, 1995). For example, a sales representative enters an order into the pany’s ERP system. When the factory begins assembling the order, shipping can check on the programs to date and estimate the expected transport date. The warehouse can check to see if the order can be filled from inventory and notify production of the number of products still needed. Once the order gets shipped, the information goes directly into the sales report for upper management.ERP provides a backbone for the enterprise. It allows a pany to standardise its information systems. Depending on the applications, ERP can handle a range of tasks from keeping track of manufacturing levels to balancing the books in accounting. The result is an anisation that has streamlined the data flow between different parts of business (Lieber, 1995). In essence, ERP systems get the right information to the right people at the right time (Sheridan, 1995).11 / 72As a result of ‘island automation’ of individual parts of a pany there are hardly, if any, links between those parts. However staff of one department need a better understanding of other departments’ processes. ERP systems are helpful in this context. These systems take care of the entire administrative process of the various units within a pany. A pany can use an ERP package to drive all processes, such a financial management, sales forecasting, purchasing, inventory management, production control, logistics, project management, service and maintenance. Examples of ERP systems are Baan, Oracle, JD Edwards and SAP. Advanced Planning and Scheduling“An APS system is a system that suits like an umbrella over the entire chain, thus enabling it to extract realtime information from that chain, with which to calculate a feasible schedule, resulting in a fast, reliable response to the customer. With the help of APS it is now possible to answer customer enquiries within seconds. This is just one of the possibilities of APS. The suppl