In this paper, we derive a utilization bound on schedulability of apriodic tasks with arbitrary arrival times, execution times, and deadlines. To the author's knowledge, this is the rst time a utilization bound is derived for the aperiodic task model. It allows constructing an O(1) admission test for aperiodic tasks. Earlier admission tests are at best O(n). We show that deadline-monotonic sche...

Single server queueing system in retrial is investigated, as well optional re-service,customer search and delayed repair. Furthermore, the permitted to take a vacation under Modified Bernoulli vacation. In this model, some of customer’s seek voluntary reservice for identical service taken, dissatisfied with first attempt without entering group (probability r1) or leaving area 1 – r1). The faili...

Consideration is given to a discretetime queueing system with inverse discipline, service interruption and resumption, second-order geometrical demand arrival, arbitrary (discrete) distribution of demand length and finite storage. Each demand entering the queue has random volume besides its length. The total volume of the demands in the queue is limited by a certain number. Formulae for the sta...

Web services as independent software components are published on the Internet by service providers and services are then called by users’ request. However, in many cases, no service alone can be found in the service repository that could satisfy the applicant satisfaction. Service composition provides new components by using an interactive model to accelerate the programs. Prior to service comp...

Today, in a competitive market, service organizations and producers have a great attention to optimization and customer satisfaction in order to become competitive. Service organization must reduce the number of arrival, waiting time and service time in the queue to increase the customer satisfaction. In this paper by the aim of queuing theory we analyze the optimal amount of increment in a rep...

This paper investigates a discrete-time impatient customer queue with Bernoullischedule vacation interruption. The vacation times and the service times during regular busy period and during working vacation period are assumed to follow geometric distribution. We obtain the steady-state probabilities at arbitrary and outside observer’s observation epochs using recursive technique. Cost analysis ...

This article presents a perishable (s; S) inventory system under continuous review at a service facility in which a waiting hall for customers is of nite size M. The arrival instants of customers to the service station constitutes a Poisson process. The life time of each items is assumed to be exponential. All arriving customers demand the rst "essential" service, whereas only some of them dema...

To solve interaction and discovery problems, Web services need to be unambiguously described. Existing technologies, such as WSDL describe the functional aspects of Web services, network service end points and interfaces. The semantic aspects are more difficult to handle, as different organizations operate in different ways, and may use different information models and domain specific vocabular...

In modern computer systems, long-running jobs are divided into a large number of short tasks and executed in parallel. As the system size and complexity scales up, the task service times become highly random and the job service time is constrained by the slowest straggling tasks. An efficient solution is to replicate a task on multiple servers and wait for one task copy to finish early. However...