【作者】 孙兆兵；

【导师】 王保良；

【作者基本信息】 浙江大学 ， 检测技术与自动化装置， 2012， 硕士

【摘要】 饮用水安全事关国计民生,人类对水资源的过度开发导致的水环境问题对饮用水安全具有严重的威胁。水质预警系统对水质进行实时分析评价、预警,可以有效控制和减少水质恶化造成的危害,达到对水质恶化有效认知和控制的目的,使整个饮用水安全保障体系进入良性循环。水质预测是水质预警系统构建的一项基础性工作,及时有效的水质预测可以为水质预警系统提供可靠的评价及预警依据。当前水质预测研究中,多采用单一水质预测方法对水质进行预测,某些针对特定单一预测方法的组合预测缺少一般框架性组合方法；概率性水质预测还没有引起广泛关注。针对这一状况,本文进行了基于概率组合的水质预测方法研究,并结合某水质预警项目,构建了典型渐变性水源水质污染预警系统。本文的主要工作和创新点如下：(1)提出了基于概率组合的水质预测方法。组合预测采用优势矩阵法对各单一预测方法加权融合,能够有效改善预测效果,并可以进一步扩展新方法；概率性预测基于对历史预测的统计,给出水质指标在一定置信度下的区间性预测结果。(2)进行了旨在验证概率组合水质预测方法有效性的水质预测实验。利用基于支持向量回归机和灰色系统的水质预测模型以及二者的组合模型、基于BP神经网络和灰色系统的水质预测模型以及二者的组合模型对钱塘江某断面水质进行预测,并给出预测效果分析；进行概率性预测实验,并对概率性预测有效性进行检验。结果表明组合预测方法能够有效提高水质预测效果,对于不同的单一水质预测方法具有良好的适应性和自寻优能力；概率性预测有效性能够得到验证,并成功给出一定置信度下的区间性预测结果。(3)构建了典型渐变性水源水质污染预警系统。基于概率组合水质预测方法,结合水质安全评价、预警信息发布等模块,进行了系统集成,建立了从现场水质监测信息到水质预测、水质安全评价、水质预警信息发布的典型渐变性水源水质污染预警系统,并结合水质预警课题实践,在三示范地进行了示范应用。更多还原

【Abstract】 The safety of drinking water which has been threaten seriously by human over-exploitation of the water resources and environment is closely related to people’s livelihood. Water quality early-warning system can effectively reduce and control the harm caused by the deterioration of water quality through the real time water quality monitor, assessment and early-warning. Prompt and effective water quality prediction can provide a reliable basis for water quality assessment and early-warning.In the current study of water quality prediction, researchers prefer single prediction methods for water quality prediction, and the existing combination methods for water quality prediction lack of a framework approach. The probability prediction is always based on an assumption that water quality index follows certain probability distribution. Base on probability and combination, a method for water quality prediction is proposed in this thesis. A water quality early-warning system for typical sustained water pollution is built with the demands of the practice of a certain water quality early-warning project.The main contents and innovative points are summarized as follows:(1)A water quality prediction method based on probability and combination is proposed. The method combines the prediction results of different single methods through Odds-Matrix method and it can improve the performances of prediction effectively. It is worth noting that the combination-forecast approach can be extended to new methods. The probability of prediction is established through statistical analysis of historical prediction data and hence the validation of the method is achieved along with interval estimation under certain confidence level.(2)A water quality prediction experiment aimed to verify the effectiveness of the method based on probability and combination is carried out. Two groups of water quality prediction methods are developed for a monitoring section of Qiantang River to conduct this work. One of the groups is the methods based on Grey Model theory. Support Vector Regression and the combination of them and the other one is the methods based on Grey Model theory, BP neural network and the combination of them. The analysis of the effects of these prediction methods and the experiment of probability prediction is also developed. The experimental results indicate that the combination-forecast approach performs better than single prediction methods. The validity of probability establishment can be checked effectively. According to the results, the interval prediction under certain confidence level can be given.(3) A water quality early-warning system for typical sustained water pollution is built. The system integration is carried out with the combination of the modules of the water quality prediction method based on probability and combination, water quality safety assessment and early-warning information issue. And the early-warning system for typical sustained water pollution which can achieve a complete water quality early-warning process from the monitoring data to water quality prediction, safety assessment and information issue is established. With the practice of the water quality early-warning project, the system has been well applied in three demonstration areas.更多还原