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基于多球中子谱仪的解谱算法研究现状
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作者 范启蒙 吕宁 +1 位作者 过惠平 张全虎 《现代应用物理》 2023年第3期90-96,共7页
基于有限的探测器响应计数求解中子能谱是一个典型的非适定问题,高效准确求解能谱具有较大困难。针对该问题,广泛调研了基于多球中子谱仪求解中子能谱的原理与数学模型,指出中子解谱面临的最大困难在于先验信息的缺失;从利用先验信息的... 基于有限的探测器响应计数求解中子能谱是一个典型的非适定问题,高效准确求解能谱具有较大困难。针对该问题,广泛调研了基于多球中子谱仪求解中子能谱的原理与数学模型,指出中子解谱面临的最大困难在于先验信息的缺失;从利用先验信息的角度讨论了目前常见中子解谱算法的原理与特点;在如何利用先验信息的统一框架下,分析了最小二乘法、奇异值截断法、正则化方法、智能算法和压缩感知算法在中子解谱中的应用,指出不同解谱算法的本质区别在于利用先验信息种类和形式的不同。为准确求解能谱,须在解谱算法中合理地增加关于能谱的先验信息,在信号处理领域出现的新理论与新方法可被借鉴用于中子解谱问题,通过进一步挖掘利用先验信息来改善求解能谱的结果。 展开更多
关键词 多球中子谱仪 中子能谱 少道解谱 非适定问题 先验信息
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Study and Application of Fault Prediction Methods with Improved Reservoir Neural Networks 被引量:2
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作者 朱群雄 贾怡雯 +1 位作者 彭荻 徐圆 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2014年第7期812-819,共8页
Time-series prediction is one of the major methodologies used for fault prediction. The methods based on recurrent neural networks have been widely used in time-series prediction for their remarkable non-liner mapping... Time-series prediction is one of the major methodologies used for fault prediction. The methods based on recurrent neural networks have been widely used in time-series prediction for their remarkable non-liner mapping ability. As a new recurrent neural network, reservoir neural network can effectively process the time-series prediction. However, the ill-posedness problem of reservoir neural networks has seriously restricted the generalization performance. In this paper, a fault prediction algorithm based on time-series is proposed using improved reservoir neural networks. The basic idea is taking structure risk into consideration, that is, the cost function involves not only the experience risk factor but also the structure risk factor. Thus a regulation coefficient is introduced to calculate the output weight of the reservoir neural network. As a result, the amplitude of output weight is effectively controlled and the ill-posedness problem is solved. Because the training speed of ordinary reservoir networks is naturally fast, the improved reservoir networks for time-series prediction are good in speed and generalization ability. Experiments on Mackey–Glass and sunspot time series prediction prove the effectiveness of the algorithm. The proposed algorithm is applied to TE process fault prediction. We first forecast some timeseries obtained from TE and then predict the fault type adopting the static reservoirs with the predicted data.The final prediction correct rate reaches 81%. 展开更多
关键词 Fault prediction Time series Reservoir neural networks Tennessee Eastman process
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A Control of Uncertain Nonlinear Systems with Unknown Control Direction Via Adaptive Backstepping
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作者 郑兆顺 《Chinese Quarterly Journal of Mathematics》 CSCD 北大核心 2007年第2期276-281,共6页
The adaptive stabilization problem of nonlinear systems are studied. For a class of uncertain nonlinear systems with unknown control direction, we proposed a robust adaptive backstepping scheme withσ-modification by ... The adaptive stabilization problem of nonlinear systems are studied. For a class of uncertain nonlinear systems with unknown control direction, we proposed a robust adaptive backstepping scheme withσ-modification by introducing Nussbaum function and Backstep- ping methods, and proved that all the signals of the closed-loop systems are bounded. 展开更多
关键词 nonlinear system adaptive control BACKSTEPPING unknown control direction
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