“…Consequently, deep SSL that introduces the superiority of deep models to the classic SSL frameworks has attracted much attention and a considerable number of deep SSL methods have been proposed. Deep SSL methods can be classified into five categories, i.e., consistency regularization methods [24], [25], [26], [27], [28], [29], [30], [31], [32], [33], pseudo-labeling methods [34], [35], [36], [37], [38], [39], [40], [41], [42], [43], [44], holistic methods of consistency regularization and pseudo-labeling [45], [46], [47], [48], [49], deep generative SSL methods [50], [51], [52], [53], [54], [55] and deep graph-based SSL methods [56], [57], [58], [59], [60]. Deep SSL methods have been successful applied into various tasks such as image classification [49], object detection [61], semantic segmentation [62], text classification [63], question answering [64], etc.…”