Pessimistic Rescaling and Distribution Shift of Boosting Models for Impression-Aware Online Advertising Recommendation. - Paolo Basso; Arturo Benedetti; Nicola Cecere; Alessandro Maranelli; Salvatore Marragony; Samuele Peri; Andrea Riboni; Alessandro Verosimile; Davide Zanutto; Maurizio Ferrari Dacrema (RecSys Challenge, 2023)