【正文】 附件附件外文翻譯英文Waiting lines and simulationThe “miss manners” article pokes fun at one of life’s realities。 having to wait in boubt those waiting in line would all agree that the solution to the problem is obvious。simply add more servers or else do something to speed up both edeas may be potential solutions,there are certain subleties that must be dealt with. For one thing, most service systems have the capacity to process more customers over the long run than they are called on to process. Hence,the problem of customers waiting is a shortterm phenomenon. The other side of the the coin is that at certain times the servers are idle, waiting for customers. Thus by increasing the service capacity, the server idle time would increase even more. Consequently,in designing service systems,the designer must weiht the cost of providing a given level of service capacity against the potential(implicit) cost of having customers wait for service. This planning and analysis of service capacity frequently lends itself to queuing theory,which is a mathematical approach to the analysis of waiting lines.The foundation of modern queuing theory is based on studies about automatic dialing equipment made in early part of the twentieth century by Danish telephone engineer . Prior to World War II,very few attempts were made to apply queuing theory to business problems. Since that time, queuing theory has been applied to a wide range of problems.The mathematics of queuing can be plex。for that reason,the emphasis here will not be on the mathematics but the concepts that underlie the use of queuing in analyzing waitingline problems. We shall rely on the use of formulas and tables for analysis.Waiting lines are monly found wherever customers arrive randomly for services. Some examples of waiting lines we encounter in our daily lives include the lines at supermarkdt checkouts,fastfood restaurants,aipport ticket counters,theaters, post offices,and toll booths. In many situations, the “customers” are not people but orders waiting to be filled ,trucks waiting to be unloaded,jobs waiting to be processed,or equipment awiting repairs. Still other examples include ships waiting to dock, planes waiting to land,hospital patients waiting for a nurse,and cars waiting at a stop sign.One reason that queuing analysis is important is that customers regard waiting as a nonvalueadded activity. Customers may tend to associate this with poor service quality，especially if the wait is long. Similarly, in an organizational setting, having work or employees wait is nonvalueadded—the sort of waste that workers in JIT systems strive to reduce. The discussion of queuing begins with an examination of what is perhaps the most fundamental issue in waitingline theory:why is there waiting? Why is there waiting?Many people are surprised to learn that waiting lines tend to form even though a system is basically underloaded. For example, a fastfood restaurant may have the capacity to handle an average of 200 orders per hour and yet experience waiting lines even though the average number of orders is only 150 per hour. The key word is average. In reality,customers arrives at random intervals rather than at evenly spaced intervals,and some orders take longer to fill than others. In other words, both arrivals and service times exhibit a high degree of variability. As a result, the system at times bees temporarily overloaded, giving rise to waiting lines。at other times, the systems is idle because there are no customers. Thus,although a system may be underloaded from a macro standpoint, varialilities in arrivals and service mean that at times the system is overloaded from a micro standpoint. It follows that in systems where variability is minimal of nonexistent(.,because arrivals can be scheduled and service time is constant),waiting lines do not ordinarily form.Managerial Implications of Waiting LinesManagers have a number of very good reasons to be concerned with waiting lines. Chief among those reasons are the following:1. The cost to provide waiting space.2. A possible loss of business should customers leave the line before being served or refuse to wait at all possible loss of goodwill. possible reduction in customer satisfaction. resulting congestion may disrupt other business operations and/or customers.Goal of WaitingLine AnalysisThe goal of queuing is essentially to minimize total costs. There are two basic categories of cost in a queuing situation: those associated with customers waiting for service and those associated with capacity. Capacity costs are the costs of maintaining the ability to provide service. Examples include the number of bays at a car wash, the number of chechkouts at a supermarket, the number of repair people to handle equipment breakdowns, and the number of lanes on a highway. When a service facility is idle, capacity is lost since it cannot be stored. The costs of customer waiting include the salaries paid to employees while they wait for service(mechanics waiting for tools,the drivers of trucks waiting to unload),the cost of the space for waiting(size of doctor’s waiting room,length of driveway at a car wash, fuel consumed by planes waiting to land),and any loss of business due to customers refusing to wait and possibly going elsewhere in the future.A practical difficulty frequently encountered is pinning down the cost of customer waiting time, especially since major portions of that cost are