On a Multi-server Priority Queue with Preemption in Crowdsourcing
A c–server queueing system providing service to two types of customers, say, Type 1 and Type 2 to which customers arrive according to a marked Poisson process is considered. A Type 1 customer has to receive service by one of c servers while a Type 2 customer may be served by a Type 1 customer (with probability p) who is available to act as a server soon after getting own service or by one of c servers. Upon completion of a service a free server will offer service to a Type 1 customer on a FCFS basis. However, if there is no Type 1 customer waiting in the system, that server will serve a Type 2 customer if one of that type is present in the queue. The service time is exponentially distributed for each category. We consider preemptive service discipline. Condition for system stability is established. Crucial system characteristics are computed.
KeywordsCrowdsourcing Queueing system Preemptive service Matrix-analytic method
Research of the first and second authors is supported by Kerala State Council for Science, Technology & Environment (No. 001/KESS/2013/CSTE). Research of the third author is supported by the University Grants Commission, Government of India, under Faculty Development Programme (Grant No. F. FIP/12th Plan/KLMG003TF05).
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