关键词： Travel time   Economic models   Waiting line problems   Cost estimates   Marginal costs   Travel expenses   Unit costs   Modeling   Population distributions  

摘要： Studies of industrial waiting line problems typically involve determining the proper balance between the amount of service and the amount of waiting for that service. This paper presents some basic results for the case where the study is to be based upon fundamental cost considerations and the assumption of an infinite calling population. Included are a number of economic models and accompanying procedures for determining the level of service which minimizes the total of the expected cost of service and the expected cost of waiting for that service.

关键词： 资本   增长模型   均衡模型   经济模型   就业   产量  

摘要： 美国《政治经济学杂志》(1961年6月号)评论说,宏量经济学分成四部分,即产量、就业和价格的短期均衡模型;长期增长模型;商业变动模型;以及分配模型。有人认为可以把这些模型中的两个或者

关键词： 灌区   土壤盐渍化   土壤水盐运移模型   气候模式   经济模型   生态安全