基于退火遗传算法的城市给水管网优化研究-市政工程专业论文.docxVIP

中文 中文摘要 摘 要 城市给水系统是现代化城市最重要的基础设施之一 是城市文明 经济发 展和现代化水平的重要标志 给水管网的布置和结构不仅在很大程度上影响到 给水工程的总造价和运行管理中的能耗 而且还会影响到供水水质 目前 采用遗传算法求解管网优化问题正逐渐被国内外研究者所重视 其 中对约束条件的处理是遗传算法理论与应用研究中的热点问题之一 解决约束 优化问题的关键是如何平衡来自目标函数最优化与满足约束条件这两方面的压 力 目前主要采用罚函数法来处理带约束的优化问题 其实际应用的难点在于 如何设计适合问题的罚系数以平衡这个压力 在实际应用遗传算法时 容易出 现早熟和收敛性差等缺点 因而使得这类方法很难真正得到广泛应用 模拟退火算法是一种通用的优化算法 算法易于实现 且可有效避免陷入 局部极小值而最终趋于全局最优 但其计算时间长 效率较低 尽管如此 模 拟退火算法仍然在工程中得到了广泛应用 本文在对几种常见优化方法进行分析 比较的基础上 采用不可行度的概 念来直接产生满足一定约束条件的初始群体 从而避免了选择罚系数的麻烦 然后采用自适应的退火遗传算法进行迭代计算 最终求得最优解 在工程实例 中的成功应用表明 该算法在收敛速度 最优解的质量方面远远优于传统遗传 算法 作者还对退火遗传算法的性能进行分析和探讨 对算法中的有关参数的取 值范围提出建议 关键词 城市给水管网 水力计算 优化算法 不可行度 退火遗传算法 I 英文 英文摘要 ABSTRACT Urban water supply system is one part of important fundamental facilities of model city. And it is a mark of civilization and economy and modernization level. Urban water distribution network influence obviously not only the total cost of water supply engineering and energy consumption during management but also water quality on network layout and pipes’ size. Today it is thought much by researchers in domestic and overseas that using genetic algorithm to optimize the network. How to deal with constraints is one important part of focuses which are very important in genetic algorithm methods to optimization constraint functions. It is a key to how to balance the pressure from between the optimization of objective function and the satisfaction of constraints. Penalty function method is mainly used for optimization of constraint functions. But it is difficult to design suitable penalty factor to balance the pressure. Practically the shortcomings include the bad astringency and the premature solution of optimization and so on when using genetic algorithm to optimize the network. So the method can’t be used really in optimization problems. Simulated Annealing is an universal algorithm and it is easily accomplished. And it can be effectively avoid premature solution. But it shortcomings include long computer time and low efficiency when using Simu