During the situation life (lifespan), it is useful to trace the status of a situation in terms of Situation Management. Therefore, patterns exist as a mechanism similar to the “polling” that keeps the system informed about the situation’s status. Once the situation is identified, the patterns could be used to make sure that the entity still in the same situation (did not evolve or vanish). For instance, the situation of the emergency room needs to be traced, as it is a critical and demanded room. Fig. 2: Simplified XACML data flow model The aggregation is possible using the new fashion of target section in V3, becomes independent of the four tuples (Subject, Resource, Action and Environment). Thanks to the XACML V3 category property, it is possible to target the policy to new attribute categories, such as situations. So, we define the category filled within the target section of each XACML policy to be attached to situation attribute. Therefore, the value of situations will target the Policy Decision Point (PDP) towards the correct set of rules to be evaluated. As a result, rules were aggregated by situations. XACML provides also a management architecture that describes the different entities and their roles related to the Decision-Making process (Figure 2). Fig. 3: BTG Situation Cycle
