Our objective is to develop a dependable real-time processing and system. To develop a real-time dependable execution model, we are investigating and trying to expand an access control - RBAC and UCON authorization mechanisms, also we are integrating them into the real-time system using TMO (Time-triggered Message-triggered Object) scheme. This system should not only satisfy the security policies but also finish jobs by the timing constraints - deadline. Performing the security policies might be a time consuming work and the system could miss the deadline as a result of checking the access control, however we need to satisfy both of them.