ction>, 0.8). Order- Based preferences, called qualitative preferences [19] rely on binary-order relations in order to express preference over two objects (e.g., (movie.genre=action) >p (movie. genre=drama)). Clause-Based Preferences are specified through a set of predefined clauses [30] such as AROUND(A, v) clause, where the user prefers objects for which the value of the attribute A is close to V (e.g., AROUND .duration, 2 h)). Customizing the Profile Model to a Specific Usage: The profile model we have defined before is generic enough to cover most of the knowledge needed by a wide class of personalized applications. However, a given profile instance does not neces- sarily contain all model elements (dimensions, subdimensions, attributes, and pref- erences). Consequently, before using such a generic model, some customization might be done to derive a submodel (or a view) that best fits the need of a specific application domain. Such customized model becomes the reference model which is then instantiated with real user profiles. Customization of the generic profile model (GPM) is done by a set of restructuring operations such as hiding a model element, defining a new model element, and renaming a model element. These operations constitute the first set of model management operations associated to the GPM. Service Delivery Platforms 10.2.2 Context Modeling In many personalized applications, providers aim at not only satisfying users' pref- erences, but also at adapting their applications to the users' environments such as the device with which they interact, as well as to the moment or the location where the interaction happens. All these features are grouped into a context entity that complements in the provider side users' profiles. The advent of mobile and pervasive computing needs has pushed multimedia services and content providers to consider the context of users in personalization and delivery processes. This consideration gave rise to context-aware applications able to adapt their services to users' cont