COMPARATIVE STUDY OF OPTIMIZATION TECHNIQUES FOR IRRIGATION PROJECT PLANNING1

ABSTRACT: This study presents three optimization techniques for on‐farm irrigation scheduling in irrigation project planning: namely the genetic algorithm, simulated annealing and iterative improvement methods. The three techniques are applied to planning a 394.6 ha irrigation project in the town of Delta, Utah, for optimizing economic profits, simulating water demand, and estimating the crop area percentages with specific water supply and planted area constraints. The comparative optimization results for the 394.6 ha irrigated project from the genetic algorithm, simulated annealing, and iterative improvement methods are as follows: (1) the seasonal maximum net benefits are $113,826, $111,494, and $105,444 per season, respectively; and (2) the seasonal water demands are 3.03*10³ m³, 3.0*10³ m³, and 2.92*10³ m³ per season, respectively. This study also determined the most suitable four parameters of the genetic algorithm method for the Delta irrigated project to be: (1) the number of generations equals 800, (2) population size equals 50, (3) probability of crossover equals 0.6, and (4) probability of mutation equals 0.02. Meanwhile, the most suitable three parameters of simulated annealing method for the Delta irrigated project are: (1) initial temperature equals 1,000, (2) number of moves equal 90, and (3) cooling rate equals 0.95.     

神经网络及其在水库调洪演算中的应用

结合洪水灾害管理的特点建立了水库调洪演算的人工神经网络模型，阐述了其基本原理及算法，并结合某水库调洪演算实例说明了其应用。     

建筑火灾区域模拟竖孔流动的计算

本文根据建筑火灾双层区域模拟思想，给出其常微分控制方程组，并分析了其压力求解方法，然后，运用伯努力利方程推导了相邻房间通过矩形竖孔（门或窗）的质量流率计算公式，还讨论了竖孔流动中性面产生条件。在此基础上，结合一两房间、两孔建筑中烟气运动实例，运用Ｃ．Ｗ．Ｇｅａｒ刚性稳定算法对火灾发展及烟气流动过程进行了数值模拟；给出各竖孔中性面位置、数量和各主环境之间通过竖孔的质量流率；还给出各房间气体平均温升、     

石油污染土壤的生物修复技术研究及其前景

根据污染土壤的生物修复技术具有高效、无二次污染和操作管理简便的优点，本文介绍谊类技术在石油污染治理领域的应用。在概述石油的组成成分及其对环境造成的污染的基础上，重点论述了微生物和植物修复技术有效去除有机污染物的应用条件，并就目前两种技术的最新研究成果即基因技术的应用作了介绍，同时指出了石油污染土壤生物修复技术的发展趋势和应用前景。     

基于神经网络和遗传算法的城市火灾风险评价模型

以消防安全工程学与系统安全工程理论为基础,结合我国城市发展特征及消防安全管理状况,建立了城市区域火灾风险评价指标体系;针对神经网络易陷入局部极小而引起评价指标权值分布不合理的缺陷,提出了基于神经网络和遗传算法的城市火灾风险评价模型,该模型以火灾发生的可能性以及灾后的严重程度为输入单元,火灾风险等级为输出单元,采用误差反算法训练BP网络,最终得出火灾风险等级范围,有效地解决了城市火灾的动态性和非线性特征;研究实例证明了该模型的有效性,可为城市的消防安全管理提供确实可行的参考依据。     

Experimental and theoretical investigation of dry-water containing phosphoric acid for new fire suppressant

To overcome the shortcomings of phosphorus-containing compounds (PCCs, not widely used) in fire suppression, the dry water powder containing phosphoric acid was analyzed for a new fire suppressant (SiO₂-P). First, the fine conditions (solid-to-liquid ratio, stirring time and stirring speed) were determined to prepare the new powder. The particle size distributions and XPS of SiO₂-P powder were analyzed. The TG tests were conducted to study the decomposition of powder, and there was a major decomposition peak. Second, the extinguishing time of SiO₂-P powder was tested, which showed that the SiO₂-P powder containing phosphorus species could significantly improve the fire suppression ability. In addition, the kinetic parameters of powder decomposition reaction were determined by genetic algorithm based on TG results. Last, based on the decomposition products and kinetic parameters, the burning velocity and mass fraction of free radicals of CH₄/air flame with SiO₂-P powder addition were studied theoretically. The results indicated that SiO₂-P powder had great ability of reducing the burning velocity and scavenging free radicals. Furthermore, the suppression effects were analyzed, which indicated that the cooperation of H₂O and P suppression effect dominated the suppression mechanism and resulted in the good suppression efficiency.     

具有变频器的矿井低压漏电保护研究

为了解决移动变电站低压侧为变频器供电时漏电保护装置误动的问题，提出了基于傅式算法的附加直流原理漏电保护新方法。通过理论分析和MATLAB/Simulink仿真，研究了具有变频器的矿井低压供电系统附加直流原理漏电保护，提出由傅式算法分解出采样电压直流分量以反映电缆绝缘水平的保护方法；同时分析了其他因素对直流分量的影响。研究结果表明:变频器对传统附加直流保护整定值有较大影响，易造成漏电保护装置误动且无法实现电缆的在线绝缘监测；所提出的直流分量法能准确测量电缆对地绝缘电阻，且可消除电缆分布电容、变频器载波频率、变频器输出频率等其他因素的干扰；采用该漏电保护方法，可承受变频器投入时对采样电压造成的较大冲击，不必在启动期间解除漏电保护装置，能够消除在此期间存在的人身触电安全隐患。     

基于遗传神经网络的除湿机故障诊断与寿命预测

目的识别除湿机的性能状态和预测吸附剂的剩余寿命。方法针对除湿机故障过程缓变的特点,提出一种基于数据驱动的遗传神经网络模型。首先,为解决设备失效程度划分模糊的问题,由5个热力参数组成反映吸附剂劣化程度的特征向量,关联分析得到除湿机的5类故障模式。其次,利用遗传神经网络建立状态参数和故障模式的映射关系。最后,对表征设备吸附能力的主参数进行外推预测。结果训练好的诊断网络可准确地识别出设备的劣化程度及其演变过程,预测网络的预测精度非常高。结论该方法可有效地实现对除湿机的故障诊断与预测。。     

ABC算法优化SVR的磨损故障预测模型

目的为了提高故障预测的精度,针对支持向量回归SVR(Support vector machine for regression,SVR)参数选择困难的问题,提出一种采用人工蜂群(artificial bee colony,ABC)算法优化支持向量回归(SVR)的故障预测模型(ABC-SVR)。方法该模型先对样本数据进行重构,然后将故障预测误差(适应度)作为优化目标,通过ABC算法寻优找到最优的SVR参数,建立故障预测模型。最后通过实例仿真验证模型的优越性。结果采用ABC算法优化的SVR故障预测模型进行时间序列预测,能够较好地跟踪发动机滑油金属元素浓度的变化过程,并且能够提前2个取样时间预测异常情况的出现。结论 ABC-SVR模型有效解决了SVR参数选择难题,能够更加准确地表现故障变化规律,提高了故障预测精度。     

西藏自治区措勤县德能铜多金属矿床地质特征及成因分析

通过对西藏自治区措勤县德能铜多金属矿的研究发现,矿区内共6条达到工业品位的铜矿体,并伴生有铅、锌、金、银等多种有益组分,成矿地质条件较好。矿体主要赋存于燕山期石英闪长玢岩岩体外接触带及构造破碎带中,其中Cu4矿体规模最大,经深部钻孔工程及地表槽探验证,矿体品位和厚度沿走向和倾向变化系数较小。燕山晚期第一阶段第一次石英闪长玢岩侵入体是主要成矿物质来源,后期北西西向断裂构造是主要导矿和容矿构造。