 requirements of CARS. ALGORITHM 2 AUTOMATIC CONTEXTUAL MAPPINGS DISCOVERY Input: the initial user profile Pust pn}, the user behavior H' Output: the contextualized user profile CPu 1: CP , cf: 0, sp: 0 2: C & CONTEXT (H') 3 : for all RiEPu do 4 : for all Cjec do 5 : compute cf+:= confidence (pr +, Cj, H') 6: compute sp+:= support (pr +, Cj, H') compute sit: merge(cft,spt) 8 : if sit Y then 9 : CP 10: compute ecf:=confidence(pr, . Cj, H') 11: compute sp := support (pr 12: compute Sij = merge(cf,,sp ) 13: if si z y then 15: return CPu 10.4.4.1 Binding Service The profile binding takes as input the contextual user profile CP and the active context of the user Ci. It returns an operational profile OP, which contains only profile elements that have to be considered by applications within the context Ci. The operational profile is produced by filtering user ratings that are not relevant in the active context Ca' and by combining the remaining user ratings with contex- tual mapping scores. The operational profile is always related to one context Ca (active context) and can be defined as a set of contextual ratings (and not mappings): OPu = {CR11 CR n}k}. Each contextual rating is of the form CR = <pr;, w>, and is derived from a contextual mapping Mia(Ri, Ca) Sia) with R Notice that Service Delivery Platforms w = aggregate(r;, Sia) is the weight (contextual rating) of the predicate pri (e.g., item;) within the context Ca. The two reals Vi and Sia have particular semantics. In fact, Vi is a rating represent- ing the absolute importance of a given predicate pri (item or feature). In other words, it is the preference that a user has on the predicate independently of contexts. However, a daily analysis of the user behavior can reveal that the importance of the predicate pri on which Vi was expressed changes with respect to contexts, leading to the definition of a contextual importance Sia* Because of these semantics, these two numerics can be aggregated with differ- ent manners. One possibility is to multiply Vi by the cont