“…In recent years, deep learning has been proven to be the most powerful data representation method (Chao, Zhi, Dong and Liu, 2018;Chu, Huang, Xie, Tan, Kamal and Xiong, 2018;Geng, Zhang, Li, Gu, Liang, Liang, Wang, Wu, Patil and Wang, 2017;Glorot, Bordes and Bengio, 2011;Guo, Liu, Oerlemans, Lao, Wu and Lew, 2016;Hu, Wang, Peng, Qiu, Shi and Liu, 2018;Längkvist, Karlsson and Loutfi, 2014;LeCun, Bengio and Hinton, 2015;Ngiam, Khosla, Kim, Nam, Lee and Ng, 2011;Sadouk, Gadi and Essoufi, 2018;Schmidhuber, 2015;Voulodimos, Doulamis, Bebis and Stathaki, 2018a;Voulodimos, Doulamis, Doulamis and Protopapadakis, 2018b;Wu, Zhai, Li, Cui, Wang and Patil;Zhang, Liang, Li, Fang, Wang, Geng and Wang, 2017;Zhang, Liang, Su, Qu and Wang, 2018a). Deep learning methods learn a neural network of multiple layers to extract the hierarchical patterns from the original data, and provide high-level and abstractive features for the learning problems.…”