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A Fuzzy Algorithm for Real-Time Scheduling of Soft Periodic Tasks

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Many scheduling algorithms have been studied to guarantee the time constraints of real-time processes. Scheduling decision of these algorithms is usually based on parameters which are assumed to be crisp. However, in many circumstances the values of these parameters are vague. The vagueness of parameters suggests that we make use of fuzzy logic to decide in what order the requests should be executed to better utilize the system and as a result reduce the chance of a request being missed. We have proposed a new fuzzy algorithm called highest fuzzy priority first. The performance of this algorithm is compared with the well-known earliest deadline first (EDF) algorithm as well as least laxity first (LLF) algorithm through simulation. The simulations were divided into two parts. Firs, the tasks were considered to be preemptable, and second tasks were assumed to be non-preemptable. Simulation results show that this fuzzy approach outperforms the EDF and LLF. It is concluded that the proposed fuzzy approach is very promising and it has the potential to be considered for future research.
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Fuzzy Real Time Scheduling; EDF; LLF; MFDF; MFLF

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