“…Liu et al [26] propose the use of low-rank matrix completion methods for missing imputation of air pollutants given their strong spatial correlation. Okafor et al [27] compare different machine learningbased imputation methods using the sensors' time series, as well as their impact on the posterior sensor calibration, showing the superiority of Variational Autoencoders (VAE). Mondal et al [28] develop a missing value imputation method for sensor networks based on spatio-temporal graph signal reconstruction via Sobolev smoothness.…”