Department of Mathematics, The Ohio State University, 231 West 18th Avenue, Columbus, OH, 43210, USA.
Department of Mathematics and Computer Science, College of the Holy Cross, 1 College Street, Worcester, MA, 01609, USA.
Bull Math Biol. 2023 Jul 7;85(8):77. doi: 10.1007/s11538-023-01175-y.
A time series is an extremely abundant data type arising in many areas of scientific research, including the biological sciences. Any method that compares time series data relies on a pairwise distance between trajectories, and the choice of distance measure determines the accuracy and speed of the time series comparison. This paper introduces an optimal transport type distance for comparing time series trajectories that are allowed to lie in spaces of different dimensions and/or with differing numbers of points possibly unequally spaced along each trajectory. The construction is based on a modified Gromov-Wasserstein distance optimization program, reducing the problem to a Wasserstein distance on the real line. The resulting program has a closed-form solution and can be computed quickly due to the scalability of the one-dimensional Wasserstein distance. We discuss theoretical properties of this distance measure, and empirically demonstrate the performance of the proposed distance on several datasets with a range of characteristics commonly found in biologically relevant data. We also use our proposed distance to demonstrate that averaging oscillatory time series trajectories using the recently proposed Fused Gromov-Wasserstein barycenter retains more characteristics in the averaged trajectory when compared to traditional averaging, which demonstrates the applicability of Fused Gromov-Wasserstein barycenters for biological time series. Fast and user friendly software for computing the proposed distance and related applications is provided. The proposed distance allows fast and meaningful comparison of biological time series and can be efficiently used in a wide range of applications.
时间序列是一种在许多科学研究领域(包括生物科学)中都非常丰富的数据类型。任何比较时间序列数据的方法都依赖于轨迹之间的成对距离,而距离度量的选择决定了时间序列比较的准确性和速度。本文介绍了一种用于比较时间序列轨迹的最优传输类型距离,这些轨迹允许位于不同维度的空间中,或者沿每个轨迹具有不同数量的点,并且这些点可能不均匀地间隔。该构造基于修改后的 Gromov-Wasserstein 距离优化程序,将问题简化为实线上的 Wasserstein 距离。由此产生的程序具有闭式解,并且由于一维 Wasserstein 距离的可扩展性,计算速度很快。我们讨论了这种距离度量的理论性质,并在具有一系列常见于生物学相关数据的特性的多个数据集上经验性地证明了所提出的距离的性能。我们还使用我们提出的距离来证明,与传统的平均方法相比,使用最近提出的融合 Gromov-Wasserstein 重心来平均振荡时间序列轨迹可以在平均轨迹中保留更多的特征,这表明融合 Gromov-Wasserstein 重心可用于生物时间序列。提供了用于计算所提出的距离和相关应用的快速且用户友好的软件。所提出的距离允许快速有效地比较生物时间序列,并且可以在广泛的应用中有效地使用。