论文标题

基于形状的流行预测评估

Shape-based Evaluation of Epidemic Forecasts

论文作者

Srivastava, Ajitesh, Singh, Satwant, Lee, Fiona

论文摘要

传统上,对正在进行的流行病进行了传染病预测,以数值目标进行,交流和评估-1、2、3和4周,病例,死亡和住院治疗。尽管预测这些数值目标以评估疾病的负担有很大的价值,但我们认为传达流行病的未来趋势(形状描述)也有价值 - 例如,如果案件将保持平坦或预期潮流。为了确保所传达的内容有用,我们需要能够评估预测形状与地面真相形状的匹配程度。我们将数值预测的转换定义为``shapelet'' - 空间表示形式,而不是将其视为分类问题(一个$ n $形状)。在此表示中,每个维度对应于形状与感兴趣形状之一(塑形)的相似性。我们证明,这种表示形式满足了两个人认为相似的形状的属性,而彼此之间的映射却很近,反之亦然。我们证明,我们的代表能够合理地捕获COVID-19案件和死亡时间序列的趋势。通过此表示,我们定义了一个评估度量和多个模型之间一致性的度量。我们还将多个模型的塑形空间集合定义为其碎屑空间表示的平均值。我们表明,该合奏能够准确预测Covid-19案例和趋势的未来趋势的形状。我们还表明,模型之间的一致性可以很好地说明预测的可靠性。

Infectious disease forecasting for ongoing epidemics has been traditionally performed, communicated, and evaluated as numerical targets - 1, 2, 3, and 4 week ahead cases, deaths, and hospitalizations. While there is great value in predicting these numerical targets to assess the burden of the disease, we argue that there is also value in communicating the future trend (description of the shape) of the epidemic -- for instance, if the cases will remain flat or a surge is expected. To ensure what is being communicated is useful we need to be able to evaluate how well the predicted shape matches with the ground truth shape. Instead of treating this as a classification problem (one out of $n$ shapes), we define a transformation of the numerical forecasts into a ``shapelet''-space representation. In this representation, each dimension corresponds to the similarity of the shape with one of the shapes of interest (a shapelet). We prove that this representation satisfies the property that two shapes that one would consider similar are mapped close to each other, and vice versa. We demonstrate that our representation is able to reasonably capture the trends in COVID-19 cases and deaths time-series. With this representation, we define an evaluation measure and a measure of agreement among multiple models. We also define the shapelet-space ensemble of multiple models as the mean of their shapelet-space representations. We show that this ensemble is able to accurately predict the shape of the future trend for COVID-19 cases and trends. We also show that the agreement between models can provide a good indicator of the reliability of the forecast.

扫码加入交流群

加入微信交流群

微信交流群二维码

扫码加入学术交流群,获取更多资源