The Application Of Ranking Genetic Algorithms On The Optimal Design Of Water Supply Networks

Urban water supply networks are an important part of the water supply systems. On one hand, it is a bridge linking water-works with consumers. On the other hand, it accounts for 50~80 percent of total water supply systems. Therefore, it is essential to optimize the water supply networks for reducing the paving cost.The optimal design of water supply networks has been broadly and deeply studied by a lot of domestic and foreign scholars just because of its important status in water supply engineering. These scholars put forward a few kinds of optimal methods, such as linear programming method, nonlinear programming method, dynamic programming method and simple genetic algorithms (SGA). However, these methods all have some limitations on practice.This paper, firstly, expatiates the content and significance about optimal design of water supply networks, briefly introduces various optimal methods that have been advanced, analyzes these methods and points out their limitations. Secondly, it introduces the principle of genetic algorithms (GA). It takes cost of water supply networks as objective function and sets up the GA model on optimal design of water supply networks. Based on SGA, the paper sets up a new improved genetic algorithms - ranking genetic algorithms (RGA) that integrated a new intelligent optimization method (genetic algorithms optimization method) and a classical optimization method (heuristic optimization method) perfectly. At the same time, it provides with two examples (one for new-built, the other for expansion), applications of the algorithms show that RGA is far better than SGA no matter at results or at runtime. At the end, the author recognizes the further works that for us to do.