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Advanced Topics in Real-Time Systems

Advanced Topics in Real-Time Systems
type: Seminar (S)
chair: Chair of Micro Hardware Technologies for Automation
semester: SS 2012

40.28 Raum 001


14:00-15:30 on 07.05.2012

lecturer: Prof. Dr. Jian-Jia Chen
sws: 2
ects: 2
lv-no.: 24840

Real-time systems play a crucial role in many applications, such as avionic control systems, automotive electronics, telecommunications, industrial automation, and robotics. Such safety-critical applications require high reliability in timing assurance to prevent from serious damage to the environment and significant human loss.

 This seminar will target at several advanced topics in real-time systems. We will target at

  • Multiprocessor scheduling
  • Multi-criticality scheduling
  • Timed-automata and its applications in real-time systems

Multiprocessor Scheduling: As embedded systems have started towards multicore and multiprocessor platforms, the computing system has to effectively and efficiently schedule and execute programs/tasks on such platforms. To schedule tasks on multiprocessor platforms, there are three alternative paradigms adopted in the literature: partitioned, global, and semi-partitioned scheduling.  The partitioned scheduling approach statically partitions tasks onto processors, in which a task is statically assigned on a specific processor. That is, all the jobs of a task are executed on a specific processor. The global scheduling approach decides the scheduling of the jobs by allowing a job to be migrated from one processor to another.  The semi-partitioned scheduling approach assigns most tasks statically onto processors by only dividing a few tasks into sequential subtasks to be executed on different processors. The partitioned scheduling approach is more restricted, but requires no run-time management. The global scheduling approach requires more run-time overhead, while the semi-partitioned scheduling approach has moderate run-time overhead

Mixed-criticality Scheduling: Traditional timing verificatins in real-time systems separate the worst-case execution time of a program and the worst-case response time of a task for the ease of analysis. However, as worst-case execution time analysis is usually quite pessimistic and may be much worse than the real cases. The mixed-criticality scheduling targets at the ease of certifications by considering different tasks with different criticality levels.

Time-automata: A Timed Automaton (TA) is a finite state machine equipped  with clocks running all at the same speed.  Transitions (called edges) between states (called locations) are activated/deactivated according to the value currently held by each clock. When changing location (via traversal of an activated edge) clocks are reset. Timed Automata can be used for verifying the timing properties in real-time systems. There have been several applications in the recent years by using timed automata in real-time systems.



In this seminar we will survey the existing body of research in this domain and identify the important scientific challenges for these advanced topics in real-time systems. Areas covered will be fairly broad and will equip participants with necessary knowledge to analyze the novel approaches in the field.

Each of the participants will be expected to go through the relevant literature and prepare a scientific report of about 15 pages on the assigned topic and present the findings through a presentation of 20 minutes in the end of the course. All the presentations will be held at the end of the semester in block form in July 2012. The topics will be allocated in the first meeting. Most of the administrative issues will be addressed in the first meeting on 07 May 2012 at 14:00 in seminar room of IPR (room 001 in Bldg. 40.28).