Internet usage has been integrated into most of our activities because of the convenience and accessibility it offers. Arguably, the most common holiday-related online activity users engage in is shopping. Each year, online shoppers troop online to search for the latest promos, coolest gifts, and biggest bargains or to book flights and reservations to go on their dream vacations during the Chri...

This report presents a method for analyzing a queueing model with repeated inhomogeneous vacations. At the end of a vacation, the server goes on another vacation, possibly with a different probability distribution, if during the previous vacation there have been no arrivals. In order to get an insight on the influence of parameters on the performance, we choose to study a simple M/G/1 queue (Po...

The present investigation deals with performance analysis of single server preemptive priority retrial queue with immediate Bernoulli feedback. There are two types of customers are considered, which are priority customers and ordinary customers. The priority customers do not form any queue and have an exclusive preemptive priority to receive their services over ordinary customers. After complet...

BACKGROUND Few prospective studies have analyzed solar and artificial (solarium) UV exposure and melanoma risk. We investigated these associations in a Norwegian-Swedish cohort study and addressed effect modification by age, pigmentary characteristics, and nevi. METHODS The cohort included women ages 30 to 50 years at enrollment from 1991 to 1992. Host factors and exposure to sun and solarium...

We consider a single-server vacation queueing system that operates in the following manner. When the server returns from a vacation, it observes the following rule. If there is at least one customer in the system, the server commences service and serves exhaustively before taking another vacation. If the server finds the system empty, it waits a fixed time c. At the expiration of this time, the...