Information Retrieval Technology: 15th Asia Information Retrieval Societies Conference, AIRS 2019, Hong Kong, China, November 7–9, 2019, Proceedings - Wang; Chen, Wei; Hao, Tianyong; Ku, Lun-Wei; Lam, Wai; Sun, Aixin; Tao, Xiaohui; Wong, Tak-Lam; Xie, Haoran (Springer International Publishing, 2020)