Information retrieval technology 15th Asia Information Retrieval Societies Conference, AIRS 2019, Hong Kong, China, November 7–9, 2019, proceedings - Wang, Fu Lee; Xie, Haoran; Lam, Wai; Sun, Aixin; Ku, Lun-Wei; Hao, Tianyong; Chen, Wei; Wong, Tak-Lam; Tao, Xiaohui (Lecture notes in computer science, 2020)