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2004 Annual Report


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R&D 100 Award

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USG

$1000 Elevator

Embedded Systems

Defect Tolerance

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Real-Time Solutions

2002/2003 Ph.D.s

2003 Patents

 

 

 

Special Report:
ECEs and Biomedicine

April 2004

Timeliness requirements of embedded real-time computers depicted as time/utility functions (TUFs)

Figure 1 above implies a constant utility for completing the action up to time tc, after which completing the action is useless.

Figure 2 above implies that the tuility of completing the action decreases up to time tc.

Figure 3 above implies that the utility for completing the action remains the same up to time ts, after which the benefit decays up to time tc.
Figure 4 above imlies a window of opportunity for action completion.

Real-time computing solutions aid scheduling, resource allocation

The Real Time Systems Laboratory has developed two novel techniques that solve scheduling and resource management problems critical to the development of autonomous navigating vehicles for space exploration as well as for command and control for air defense, surveillance/ reconnaissance radar systems, and multiphase array radars.

The Generic Utility Scheduling (GUS) algorithm is a scheduling algorithm for real-time computers. Timeliness is critical for real-time computers that interact with the physical world, such as those embedded in vehicles. Such computers typically process sensor data, such as speed or altitude, then initiate control actions, such as braking. The actions must be timely for correct operation such as staying on course or stopping before a crash.

Unlike conventional real-time scheduling algorithms that consider actions with “deadline” time constraints whose (anytime) completion before a deadline time is useful (and otherwise not), GUS handles more general time constraints such as completing actions whose utility varies (e.g., decreases, increases) with time. Further, GUS handles situations where competing requests on computing resources must be satisfied in a mutually exclusive manner for maintaining resource integrity. GUS orders actions to maximize their total accrued utility, while respecting resource mutual exclusion constraints.

The research team, headed by Binoy Ravindran, also has devised a mathematically verified software framework for implementing utility accrual algorithms such as GUS on commercial off-the-shelf real-time operating systems. Called the Meta Scheduler, the framework can be used without modifying the operating system.

 
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Last updated: Wed, Jun 9, 2004