【作者】 孟庆浩；

【导师】 朱群雄；

【作者基本信息】 北京化工大学 ， 计算机应用技术， 2009， 硕士

【摘要】 近年来,神经网络集成技术已成为机器学习领域研究的热点之一,它可以获得比单个神经网络更好的泛化能力和稳定性,其中的选择性集成技术由于其在推广性和组合性方面的优势得到了广泛关注。PTA(精对苯二甲酸)作为主要的化工原料,涉及国民经济的各个方面,应用领域非常广泛,因此研究PTA生产过程具有重要的实际意义。为解决PTA流程工业中的复杂模式和工作点漂移引起的单个神经网络模型泛化能力不足和稳定性问题,本文提出一种新的基于权值信息度量网络差异度的选择性神经网络集成方法DWSEN。DWSEN利用各个子网络对应的权值去度量网络模型之间的差异性,并给出用于计算相同结构网络之间差异度的计算公式,对比传统的集成方法和目前流行的神经网络集成算法Bagging和Boosting,仿真实验结果显示DWSEN具有更好的泛化能力和更强的稳定性能。将DWSEN方法用于PTA工业中薄膜蒸发器蒸发量和溶剂脱水塔塔顶电导率的建模过程,所得集成模型能够提高PTA生产装置的软测量模型的精度和稳定性,能更好的反映蒸发量和电导率的变化趋势,本方法为工业过程的复杂机理模型分析提供了一种行之有效的建模方案。更多还原

【Abstract】 Recently, neural network ensemble has become one of hot topics of machine learning technology. And it has the advantages of generalization ability and stability than a single artificial neural network. Selective ensemble technology received extensive attentions because of its advantages of applicability and combinability.Purified terephthalic acid (PTA), as a major chemical raw material, covering all aspects of the national economy, has been applied widely in various fields. Thus, the study of PTA production process has great practical significance. In order to solve the lack of generalization and stability in single neural network model because of the complexity of mechanism and operating point drift, the paper puts forward a new selective neural network ensemble approach named DWSEN which to measure the diversity of individuals according to weights of individual networks. And it presents the formula used to calculate the diversity of networks with same network structure. Comparing with some prevailing ensemble approaches such as Bagging and Boosting, experiments reflect that DWSEN has higher generalization ability and stronger stability. The method is applied to the modeling of evaporation of Film Evaporator and tower conductivity of Solvent Dehydration Tower in PTA industrial process. Cases study show that the obtained models can possess better generalization performance, and simulate the production process better in PTA industry. DWSEN provides a well-estabilished modeling program for complex mechanism model in PTA process industry.更多还原