Uncertanity modelling using Dirichlet Distribution

Hi. I'm looking for a mathematician/engineer who will explain the IV.C (Dirichlet Distribution) and IV.D (Trustworthiness of a User Vehicle) of the attached paper with a practical example. Specifically, I'm looking to understand what's the role of Dirichlet distribution here and how Trust is calculated using Dirichlet distribution. I have an example for the previous section. If you know what's happening in IV.C and IV.D, we can discuss further. Thank you.