“…After we obtain θ t,u , ψ t,u and φ t,z , inspired by PM-2 diversification method (Dang and Croft 2012), we closely follow the work in (Liang et al 2017c;2018) and propose a streaming keyword diversification model (i.e., Algorithm 2), SKDM. To generate top-k diversified keywords for each user u at t, SKDM starts with an empty keyword set w t,u with k empty seats (step 2 of Algorithm 2), and a set of candidate keywords (step 3), v, which is the whole words v in the vocabulary, i.e., initially let v = v. For each of the seats, it computes the quotient qt[z|t, u] for each topic z given a user u at t by the Sainte-Laguë formula (step 9): qt[z|t, u] = δt,u,z 2s z|t,u +1 , where δ t,u,z is the final probability of the user u has interest on topic z at t and is set to be δ t,u,z = (1 − λ)P (z|t, u) + λP (z|t, f t,u ) (step 5), and s z|t,u is the "number" of seats occupied by topic z (in initialization, let s z|t,u = 0 for all topics (step 6)).…”