针对复杂化工过程非平稳性、事件驱动性导致的关键指标参数难以精确软测量的问题,提出了一种事件驱动的深度信念网络(event-driven deep belief network,EDDBN)软测量模型设计方法。首先,获取化工过程运行数据并搭建深度信念网络(driven...
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针对复杂化工过程非平稳性、事件驱动性导致的关键指标参数难以精确软测量的问题,提出了一种事件驱动的深度信念网络(event-driven deep belief network,EDDBN)软测量模型设计方法。首先,获取化工过程运行数据并搭建深度信念网络(driven deep belief network,DBN)模型,以数据驱动的方式对DBN模型进行训练,获得基于DBN的软测量模型。其次,根据DBN模型的训练误差变化特性定义事件,当积极事件发生时会加速当前模型参数的学习步长,当消极事件发生时会跳过当前数据样本并直接进入下一时刻的数据样本学习。这种事件驱动的选择性学习策略不仅能够有效地优化软测量模型训练过程,而且还能降低计算复杂度。同时,通过构造基于马尔可夫链的动态学习过程,分析任意连续两次事件对应输出性能势之差的有界性,给出了EDDBN训练过程的收敛性分析。最后,将EDDBN软测量模型用于湿法烟气脱硫系统二氧化硫(SO_2)浓度软测量实验,结果表明所提出的EDDBN软测量模型能够在非平稳运行工况下实现对SO_2浓度快速、精确地预测分析,并且计算复杂度在数据集(1)和数据集(2)上分别降低约63.83%和63.33%。
太阳辐射作用于气候系统的过程是复杂的非线性过程。迄今为止,人们对于太阳活动和地球运动因子影响气候系统的过程与作用机制的认识并不十分清楚,缺乏深入和系统的研究。联合国政府间气候变化专门委员会(Intergovernmental Panel on Cli...
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太阳辐射作用于气候系统的过程是复杂的非线性过程。迄今为止,人们对于太阳活动和地球运动因子影响气候系统的过程与作用机制的认识并不十分清楚,缺乏深入和系统的研究。联合国政府间气候变化专门委员会(Intergovernmental Panel on Climate Change,IPCC)评估报告认为,太阳等自然因子对现代地球气候变化的影响研究还存在很大的不确定性。不可忽视的一点是,联合国政府间气候变化专门委员会评估报告所选用的地球系统模式仅仅考虑了太阳总辐照度的变化,而对太阳辐射光谱中的紫外辐射波段影响高层大气物理和化学过程,进而与对流层大气相互作用所引起的气候变化估计不足。因此,很有必要利用新的气候资料、应用海气耦合模式评估太阳活动的影响。
Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation ac...
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Pitch produced by the lique-faction of coal was divided into two frac-tions:soluble in toluene(TS)and insol-uble in toluene but soluble in pyridine(TI-PS),and their differences in molecu-lar structure and oxidation activity were *** different carbon materi-als were produced from them by oxida-tion in air(350℃,300 mL/min)fol-lowed by carbonization(1000℃ in Ar),and the effect of the cross-linked structure on their structure and sodium storage properties was *** results showed that the two pitch fractions were obviously different after the air *** TS fraction with a low degree of condensation and abundant side chains had a stronger oxidation activity and thus introduced more cross-linked oxygen-containing functional groups C(O)―O which prevented carbon layer rearrangement during the *** a result,a disordered hard carbon with more defects was formed,which improved the electrochemical ***,the carbon materials derived from TS(O-TS-1000)had an obvious disordered structure and a larger layer spacing,giving them better sodium storage perform-ance than those derived from the TI-PS fraction(O-TI-PS-1000).The specific capacity of O-TS-1000 was about 250 mAh/g at 20 mA/g,which was 1.67 times higher than that of O-TI-PS-1000(150 mAh/g).
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