We consider a two-stage service policy for a Poisson arrival queueing system. The idle server starts to work with ordinary service rate when a customer arrives. If the number of customers in the system reaches N, the service rate gets faster and continues until the system becomes empty....

We use martingale methods to obtain an explicit formula for the expected wet period of the finite dam of capacity V, where the amounts of inputs are i.i.d exponential random variables and the output rate is one, when the reservoir is not empty. As a consequence, we obtain an explicit formula for...

We consider a G / M / 1 queue with two-stage service policy. The server starts to serve with rate of μ 1 customers per unit time until the number of customers in the system reaches λ. At this moment, the service rate is changed to that of μ 2 customers per unit time and this rate continues...

We consider a G / M / 1 queue with two-stage service policy. The server starts to serve with rate of μ<Subscript>1</Subscript> customers per unit time until the number of customers in the system reaches λ. At this moment, the service rate is changed to that of μ<Subscript>2</Subscript> customers per unit time and this rate continues...</subscript></subscript>