部分稳定氧化锆(Partially stabilized zirconia,PSZ)陶瓷因其优越的性能在航空航天工业等领域有广泛的应用。表面粗糙度是评价PSZ陶瓷磨削加工水平的关键指标,为了降低磨削表面粗糙度的预测误差,提出了一种基于相关性分析与卷积-双向...部分稳定氧化锆(Partially stabilized zirconia,PSZ)陶瓷因其优越的性能在航空航天工业等领域有广泛的应用。表面粗糙度是评价PSZ陶瓷磨削加工水平的关键指标,为了降低磨削表面粗糙度的预测误差,提出了一种基于相关性分析与卷积-双向长短期记忆神经网络(Convolution-bidirectional long short term memory neural network,CNN-BiLSTM)的PSZ陶瓷磨削表面粗糙度声发射预测模型。通过分析磨削声发射信号特征值与磨削表面粗糙度值之间相关性,筛选出磨削声发射信号与磨削表面粗糙度之间的最相关频段和特征矩阵,作为CNN-BiLSTM神经网络的输入参数以降低磨削表面粗糙度声发射预测的误差。研究结果表明,基于相关性分析与CNN-BiLSTM神经网络的PSZ陶瓷磨削表面粗糙度的平均预测误差低于3.92%。展开更多
Load forecasting is of great significance to the development of new power systems.With the advancement of smart grids,the integration and distribution of distributed renewable energy sources and power electronics devi...Load forecasting is of great significance to the development of new power systems.With the advancement of smart grids,the integration and distribution of distributed renewable energy sources and power electronics devices have made power load data increasingly complex and volatile.This places higher demands on the prediction and analysis of power loads.In order to improve the prediction accuracy of short-term power load,a CNN-BiLSTMTPA short-term power prediction model based on the Improved Whale Optimization Algorithm(IWOA)with mixed strategies was proposed.Firstly,the model combined the Convolutional Neural Network(CNN)with the Bidirectional Long Short-Term Memory Network(BiLSTM)to fully extract the spatio-temporal characteristics of the load data itself.Then,the Temporal Pattern Attention(TPA)mechanism was introduced into the CNN-BiLSTM model to automatically assign corresponding weights to the hidden states of the BiLSTM.This allowed the model to differentiate the importance of load sequences at different time intervals.At the same time,in order to solve the problem of the difficulties of selecting the parameters of the temporal model,and the poor global search ability of the whale algorithm,which is easy to fall into the local optimization,the whale algorithm(IWOA)was optimized by using the hybrid strategy of Tent chaos mapping and Levy flight strategy,so as to better search the parameters of the model.In this experiment,the real load data of a region in Zhejiang was taken as an example to analyze,and the prediction accuracy(R2)of the proposed method reached 98.83%.Compared with the prediction models such as BP,WOA-CNN-BiLSTM,SSA-CNN-BiLSTM,CNN-BiGRU-Attention,etc.,the experimental results showed that the model proposed in this study has a higher prediction accuracy.展开更多
高效合理地决策未来月度计划期的铁路运用车分配方案对满足货运市场需求和节约空车调配成本具有重要意义。针对运用车分配方案所具备的时空特性,提出一种基于卷积长短期记忆神经网络并融合物理引导思想的铁路运用车分配预测方法。首先,...高效合理地决策未来月度计划期的铁路运用车分配方案对满足货运市场需求和节约空车调配成本具有重要意义。针对运用车分配方案所具备的时空特性,提出一种基于卷积长短期记忆神经网络并融合物理引导思想的铁路运用车分配预测方法。首先,通过主要影响因素识别,筛选出货运工作量类、货运组织水平类、货车运用属性类3类主要影响指标,并通过滑动窗口划分方法构造为模型输入。随后,构建基于PG-ConvLSTM(convolutional long short-term memory,ConvLSTM)网络的铁路运用车分配预测模型。模型以卷积长短期记忆神经网络作为主体框架,基于运用车分配的先验规律设计物理不一致项构造物理引导损失函数,并使用Hyperband算法优化模型网络层数与物理不一致项权重2项超参数。最后,使用MAE、RMSE与MAPE作为评价指标,并选用BP、CNN-LSTM、CNN-GRU与ConvLSTM网络模型作为对比,基于运用车分配实际数据进行实例分析。结果表明,PG-ConvLSTM模型评价指标MAE为0.0028,RMSE为0.0034,MAPE为7.22%,相比其他神经网络模型均为最优。PG-ConvLSTM模型得益于时空关联特征的同步提取机制,有效避免时空特征经卷积后再输入循环神经网络而丢失关键信息,从而具备更优的预测性能。物理引导损失函数对预测精度提升也具有积极作用。PG-ConvLSTM模型能够高效且准确地对运用车分配方案进行预测,可为实际运营中月度计划期运用车分配方案的制定提供参考。展开更多
文摘部分稳定氧化锆(Partially stabilized zirconia,PSZ)陶瓷因其优越的性能在航空航天工业等领域有广泛的应用。表面粗糙度是评价PSZ陶瓷磨削加工水平的关键指标,为了降低磨削表面粗糙度的预测误差,提出了一种基于相关性分析与卷积-双向长短期记忆神经网络(Convolution-bidirectional long short term memory neural network,CNN-BiLSTM)的PSZ陶瓷磨削表面粗糙度声发射预测模型。通过分析磨削声发射信号特征值与磨削表面粗糙度值之间相关性,筛选出磨削声发射信号与磨削表面粗糙度之间的最相关频段和特征矩阵,作为CNN-BiLSTM神经网络的输入参数以降低磨削表面粗糙度声发射预测的误差。研究结果表明,基于相关性分析与CNN-BiLSTM神经网络的PSZ陶瓷磨削表面粗糙度的平均预测误差低于3.92%。
文摘Load forecasting is of great significance to the development of new power systems.With the advancement of smart grids,the integration and distribution of distributed renewable energy sources and power electronics devices have made power load data increasingly complex and volatile.This places higher demands on the prediction and analysis of power loads.In order to improve the prediction accuracy of short-term power load,a CNN-BiLSTMTPA short-term power prediction model based on the Improved Whale Optimization Algorithm(IWOA)with mixed strategies was proposed.Firstly,the model combined the Convolutional Neural Network(CNN)with the Bidirectional Long Short-Term Memory Network(BiLSTM)to fully extract the spatio-temporal characteristics of the load data itself.Then,the Temporal Pattern Attention(TPA)mechanism was introduced into the CNN-BiLSTM model to automatically assign corresponding weights to the hidden states of the BiLSTM.This allowed the model to differentiate the importance of load sequences at different time intervals.At the same time,in order to solve the problem of the difficulties of selecting the parameters of the temporal model,and the poor global search ability of the whale algorithm,which is easy to fall into the local optimization,the whale algorithm(IWOA)was optimized by using the hybrid strategy of Tent chaos mapping and Levy flight strategy,so as to better search the parameters of the model.In this experiment,the real load data of a region in Zhejiang was taken as an example to analyze,and the prediction accuracy(R2)of the proposed method reached 98.83%.Compared with the prediction models such as BP,WOA-CNN-BiLSTM,SSA-CNN-BiLSTM,CNN-BiGRU-Attention,etc.,the experimental results showed that the model proposed in this study has a higher prediction accuracy.
文摘高效合理地决策未来月度计划期的铁路运用车分配方案对满足货运市场需求和节约空车调配成本具有重要意义。针对运用车分配方案所具备的时空特性,提出一种基于卷积长短期记忆神经网络并融合物理引导思想的铁路运用车分配预测方法。首先,通过主要影响因素识别,筛选出货运工作量类、货运组织水平类、货车运用属性类3类主要影响指标,并通过滑动窗口划分方法构造为模型输入。随后,构建基于PG-ConvLSTM(convolutional long short-term memory,ConvLSTM)网络的铁路运用车分配预测模型。模型以卷积长短期记忆神经网络作为主体框架,基于运用车分配的先验规律设计物理不一致项构造物理引导损失函数,并使用Hyperband算法优化模型网络层数与物理不一致项权重2项超参数。最后,使用MAE、RMSE与MAPE作为评价指标,并选用BP、CNN-LSTM、CNN-GRU与ConvLSTM网络模型作为对比,基于运用车分配实际数据进行实例分析。结果表明,PG-ConvLSTM模型评价指标MAE为0.0028,RMSE为0.0034,MAPE为7.22%,相比其他神经网络模型均为最优。PG-ConvLSTM模型得益于时空关联特征的同步提取机制,有效避免时空特征经卷积后再输入循环神经网络而丢失关键信息,从而具备更优的预测性能。物理引导损失函数对预测精度提升也具有积极作用。PG-ConvLSTM模型能够高效且准确地对运用车分配方案进行预测,可为实际运营中月度计划期运用车分配方案的制定提供参考。
