Search Results (2)

Air pollution presents a serious hazard to human health and the environment for the global rise in industrialization and urbanization. While fine-grained monitoring is crucial for understanding the formation and control of air pollution and their effects on human health, existing macro-regional level or ground-level methods make air pollution inference in the same spatial scale and fail to address the spatiotemporal correlations between cross-grained air pollution distribution. In this paper, we propose a 3D spatiotemporal attention super-resolution model (AirSTFM) for fine-grained air pollution inference at a large-scale region level. Firstly, we design a 3D-patch-wise self-attention convolutional module to extract the spatiotemporal features of air pollution, which aggregates both spatial and temporal information of coarse-grained air pollution and employs a sliding window to add spatial local features. Then, we propose a bidirectional optical flow feed-forward layer to extract the short-term air pollution diffusion characteristics, which can learn the temporal correlation contaminant diffusion between closeness time intervals. Finally, we construct a spatiotemporal super-resolution upsampling pretext task to model the higher-level dispersion features mapping between the coarse-grained and fined-grained air pollution distribution. The proposed method is tested on the PM_2.5 pollution datatset of the Yangtze River Delta region. Our model outperforms the second best model in RMSE, MAE, and MAPE by 2.6%, 3.05%, and 6.36% in the 100% division, and our model also outperforms the second best model in RMSE, MAE, and MAPE by 3.86%, 3.76%, and 12.18% in the 40% division, which demonstrates the applicability of our model for different data sizes. Furthermore, the comprehensive experiment results show that our proposed AirSTFM outperforms the state-of-the-art models. Full article

The aim of this study was to investigate if the macroregions of Poland are homogeneous in terms of the observed spatio-temporal data characterizing their sustainable development. So far, works related to the sustainable development of selected territorial units have been based on data relating to a specific year rather than many years. The solution to the problem of macroregion homogeneity goes through two stages. In step one, the original spatio-temporal data space (matrix space) was transformed into a kernel discriminant coordinates space. The obtained kernel discriminant coordinates function as synthetic measures of the level of sustainable development of Polish macroregions. These measures contain complete information on the values of 27 diagnostic features examined over 15 years. In the second step, cluster analysis was used in order to identify groups of homogeneous macroregions in the space of kernel discriminant coordinates. The agglomeration method and the Ward method were chosen as commonly used methods. By means of both methods, three super macroregions composed of homogeneous macroregions were identified. Within the kernel discriminant coordinates, the differentiating power of a selected set of 27 features characterizing the sustainable development of macroregions was also assessed. To this end, five different and most commonly used methods of discriminant analysis were used to test the correctness of the classification. Depending on the method, the classification errors amounted to zero or were close to zero, which proves a well-chosen set of diagnostic features. Although the data relate only to a specific country (Poland), the presented statistical methodology is universal and can be applied to any territorial unit and spatial-temporal dynamic data. Full article