Prefix and infix probability computation in PRISM

ABSTRACT. This paper presents the recent progress concerning prefix and infix probability for PCFGs in a logic-based modeling language PRISM. A prefix is an initial substring of a sentence and likewise an infix is a substring that occurs within a sentence. The prefix probability computation is already introduced to PRISM but applications are still scarce. We describe a new application to web data that identifies visitors’ intentions, or goals visiting a website from observed sequences of their actions using prefix probability. We also discuss infix probability computation that generalize prefix probability computation. Unlike previous approaches, we compute it through parsing followed by solving a set of non-linear equations.