基于时空注意力机制的新冠肺炎疫情预测模型

新冠肺炎疫情持续蔓延给人类社会带来深远影响，准确预测各地区的病毒传播趋势对防控疫情而言至关重要。现有研究主要基于传统的时序预测模型和传染病模型，鲜有考虑疫情地区关联复杂和时序依赖性强的特点，限制了其疫情预测的性能。为此，针对新冠肺炎疫情的预测任务，提出了一种时空注意力驱动的自编码器框架。通过引入空间注意力机制捕捉病毒感染序列间的动态空间关联性，利用时间注意力机制挖掘病毒感染序列中复杂的时序依赖性，以此实现对不同地区的新冠肺炎病毒传播趋势的准确预测。在模型的编码器端，融合空间注意力机制的长短期记忆(LSTM)网络，关联目标地区与其他地区的病毒感染序列，提取该区域近期新冠肺炎疫情的时序特征。在模型的解码器端，将时间注意力机制引入基于LSTM网络的解码器中，通过捕捉病毒感染序列的时序依赖性推测未来的新冠肺炎疫情趋势变化。在多个公开的新冠肺炎疫情数据集上对所提模型进行验证，实验结果表明:所提模型的预测性能超越了LSTM等模型；在公开的欧洲部分国家新冠肺炎疫情数据集上，预测误差指标RMSE和MAE分别降低了22.3%和25.0%，在中国部分省级单位新冠肺炎疫情数据集上，RMSE和MAE分别降低了10.1%和10.4%。 

Prediction model of COVID-19 based on spatiotemporal attention mechanism

The continuous spread of the COVID-19 has brought profound impacts on human society. For the prevention and control of virus spreading, it is critical to predict the future trend of epidemic situation. Existing studies on COVID-19 spread prediction, based on classic SEIR models or naive time-series prediction models, are rarely considering the characteristics of complex regional correlation and strong time series dependence in the process of epidemic spread, which limits the performance of epidemic prediction. To this end, we propose a COVID-19 prediction model based on auto-encoder and spatiotemporal attention mechanism. The proposed model estimates the trend of COVID-19 by capturing the dynamic spatiotemporal dependence between the epidemic situation sequences of different regions. In particular, a spatial attention mechanism is implemented in the encoder section for every given region to capture the dynamic correlation between the epidemic situation time-series of the region and those of the related regions. Based on the leant correlation, an long short-term memory (LSTM) network is then applied to extract the epidemic sequential features for the given region by combining the recent epidemic situations of the region and the related regions. On the other hand, to better predict the dynamic of the future epidemic situation, temporal attention is introduced into an LSTM network-based decoder to capture the temporal dependence of the epidemic situation sequence. We evaluate the proposed model on several open datasets of COVID-19, and experimental results show that the proposed model outperforms the state-of-the-art models. The metrics of RMSE and MAE of the proposed model on the COVID-19 epidemic dataset of some European countries decreased 22.3% and 25.0%. The metrics of RMSE and MAE of the proposed model on the COVID-19 epidemic dataset of some Chinese provinces decreased 10.1% and 10.4%.