优化NARX神经网络对时间序列溶解氧的预测

为提高非线性有源自回归(NRAX)神经网络模型的预测精准度,采用主成分分析(PCA)法和灰色关联分析(GRA)法提取原始数据特征并减少输入变量的维度,通过构建PCA-NARX和GRA-NARX模型预测地表水体未来短期(48 h)溶解氧(DO)的质量浓度.结果表明:GRA-NARX模型对时间序列DO质量浓度的预测效果优于...     

电子商务物流配送体系考核指标的建立与应用

配送体系的绩效考核是配送系统的重要内容,要建立和完善适应电子商务的物流配送体系,必须研究如何建立合理的配送指标体系。文章针对上海英业达公司的实际,探讨建立了一套绩效评估指标体系,并利用层次分析法对该配送体系进行了绩效评价。     

Removing Iron and Manganese Simultaneously from Ground Water Using One-stage Biological Filter

A novel process for removing iron and manganese simultaneously in ground water,which consisted of simple aeration and one-stage filtration,was developed in this research. It was found that the biological process had much higher manganese removal efficiency than chemical contact oxidation process. At the same time,the optimal operation parameters of aeration and biological filtration such as DO concentration and pH after aeration,filtration rate before and after startup,filtration operation cycle and backwas...     

Adsorption of Phenol by Activated Carbon Prepared from Waste Rice Straw by Chemical Activation with （ NH4 ） 2 HPO4

Activated carbons,RS-1,RS-2,and RS-3,prepared from rice straw with (NH4 )2HPO4 activation were used as adsorbents for removing phenols from aqueous solutions. The maximum adsorption capadties of phenol...