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本文探讨了滴灌系统设计、管理的一个非线性最优化模型。决策变量是:管径、管长、每条支管控制的滴头数、总汇水管上的支管条数、总的灌水单元数、同时运行的灌水单元数、每组的灌水时间及滴头流量。模型用GAMS—MINOS软件包来求解。选择一个梨园来说明模型的功能。从物价对模型的影响可看出,系统本身的造价和运行管理费用,相对来说要比获得的效益小的多。当边际效益比边际费用大的时候,由模型得到的结果不是系统的最小费用值。 由模型的敏感性分析表明,产品价格是一个很重要的输入变量,它对目标函数(效益最大化)产生的影响最大。能量价格由于其常有上涨的危险,所以也是一个重要的量值,对于收益和其他费用也有不小的影响。类似地,管子的价格对目标函数的影响却较小。
In this paper, we discuss a nonlinear optimization model of drip irrigation system design and management. The decision variables are: pipe diameter, pipe length, number of drippers controlled by each branch pipe, number of branch pipes on total pipe, total number of irrigation units, number of irrigation units operating at the same time, irrigation time for each group and dripper flow rate. The model is solved with the GAMS-MINOS package. Choose a pear orchard to illustrate the model’s capabilities. From the impact of price on the model can be seen that the cost of the system itself and operation and management costs are relatively much lower than the benefits obtained. When the marginal benefit is larger than the marginal cost, the result obtained by the model is not the system’s minimum cost value. The sensitivity analysis of the model shows that product price is a very important input variable, and it has the greatest influence on the objective function (maximizing the profit). Energy prices are also an important measure because of the dangers of rising often, with no small effect on earnings and other costs. Similarly, the price of the pipe has a small effect on the objective function.