基于排队理论的渠道容量设计

Channel Capacity Design Based on Queuing Theory

在设计一个新的灌溉配水系统时,渠道容量是一个不易确定的参数,因为农场用户提出供水的时间和水量通常是不确定的,取决于季节、气候、农作物种类等因素。渠道容量对灌溉投资和服务质量有重要的影响。提出运用排队理论确定渠道容量的大小。依据该理论,服务系统需提供的容量取决于将要达到的服务水平,以及顾客到达时间和服务时间的平均密度和分布规律。将灌溉渠道容量比作排队系统的服务能力。研究了指数分配和非指数分配模型及10个连续的灌溉周期。计算实例显示,同传统的Clement方程相比,该方法的结果相当可信。

In the planning and design of a new irrigation system, one of the most significant uncertainties is the channel capacity, as numerous farmers usually request water at varying times, depending on the crop mixes, climate and season, The capacity of a channel has significant implications for investment and the irrigation performance. This study develops a new method - queuing theory, which can be used to determine the channel capacities in on-demand service. According to the theory, the capacities of service channels depend on the service levels, the average arrival and service rates, and the distributions of arrival and service events. This study incorporates the irrigation requests with queuing modelling, and indicates the channel capacities in terms of the number of the service channels in queuing systems. Both exponential and Erlang distribution models for irrigation events are developed. Ten successive irrigation intervals are also studied with the models. The values of the result from the models show that they are reasonable and reliable by comparing with that of Clement＇s first formula.