“…LDA has been applied in many fields, including pattern detection in images (Agarwal and Triggs, 2008; Coelho et al 2010) and video (Niebles et al , 2008; Wang et al , 2009), automatic essay grading (Kakkonen et al , 2008), and fraud detection (Xing and Girolami, 2007). For different research needs, scholars have performed some expansions to the LDA model, such as the author-topic model (Hwang et al , 2017), dynamic topic models (Blei and Lafferty, 2006), correlated topic models (Blei and Lafferty, 2007), non-Markov continuous-time model (Wang and Mccallum, 2006), and sentence LDA (Bao and Datta, 2014; Jo and Oh, 2011).…”