1. A non-transitory computer-accessible medium having stored thereon computer-executable instructions for modifying at least one circuit, wherein, when a computer hardware arrangement executes the instructions, the computer arrangement is configured to perform procedures comprising: dividing the at least one circuit into a plurality of regions such that each scan cell of a plurality of scan cells belongs to a single region, and the regions do not form a cycle; levelizing the regions; selecting a set of the scan cells of at least one first region that drive a plurality of interface registers that belong to at least one second region as at least one interface register; and inserting at least one shadow register into the at least one interface register.