PURPOSE Technology-related behaviors (e.g., computer use) before bedtime (BT) have been associated with poorer and shorter sleep in adolescents; however, less is known about other behaviors in relation to sleep. This study characterized a range of behaviors in the hour before bed (i.e., pre-BT behaviors [PBBs]) and examined their relationship with sleep parameters during school and vacation per...

Consider a single server retrial queueing system with pre-emptive priority service and single working vacation in which two types of customers arrive in a Poisson process with arrival rates ?1 for low and ?2 for high priority customers. We assume that regular service times follow an exponential distribution with parameters μ1 and μ2 correspondingly. The retrial is introduced for low priority cu...

We consider a batch arrival queueing system with three stage heterogeneous service provided by a single server with different (arbitrary) service time distributions. Each customer undergoes three stages of heterogeneous service. As soon as the completion of third stage of service, if the customer is dissatisfied with his service, he can immediately join the tail of the original queue. The vacat...

This paper concentrates on the steady state analysis of the discrete-time batch arrival Geo/G/1 queue with vacations. In this model, after serving all customers in the system, the server will take a random maximum number of vacations before returning to the service mode. The distributions of busy period, vacation period and vacation cycle have been given. Meanwhile, the PGFs for the off-line pe...

In this paper we analyze a single server queue with batch arrival Poisson input, two heterogeneous service with different general (arbitrary) service time distributions and two phase (compulsory and optional) server vacations with general (arbitrary) vacation period. The first phase of service is essential for all customers, as soon as the first service of a customer is completed, then with pro...

In this paper, we model a cold standby repairable system with one repairman. Suppose that the system consists of two dissimilar components and one repairman, in which component 1 is the major working unit and component 2 is the cold stand-by unit, component 1 has priority in use and repair; then the repairman takes a single vacation. Under these assumptions , we derive a model of partial differ...

We consider an M/GI/1/N queue with vacation time and exhaustive service discipline, the same queue as in Lee 9]. Focusing only on the service completion epochs (as oposed to both service completion epochs and vacation completion epochs by Lee), we present a simple analysis for the queue length distribution at an arbitrary time as well as for the waiting time distribution.