1. A computerized system comprising: a processing module configured to receive a plurality of scan operations associated with a plurality of segments of a system under test and to generate therefrom input test data configured to be applied to the system under test via a test access port; and a scheduler including a circuit model of the system under test defining the plurality of segments of the system under test, the scheduler adapted to provide the processing module with scheduling for the plurality of scan operations based on the circuit model; wherein the circuit model includes at least one attribute providing enhancing information for at least one segment of the plurality of segments, the scheduler processing the at least one attribute to dynamically modify the scheduling provided to the processing module.