We consider in this paper an M/G/1 type queueing system with the following extensions. First, the server is unreliable and is subject to random breakdowns. Second, the server also implements the well-knownN-policy.Third, instead of a Bernoulli vacation schedule, the more general notion of binomial schedule withK vacations is applied. A cost function with two decision variables is developed. A n...

Electronic Assessment systems usually provide an authoring tool for creating activities (mainly closed-type questions) and administering the flow of their presentation and are also complemented with a delivery environment for learners. In this paper, we discuss learner’s control over authored assessment. The prototype application, ReACTS (Re-Adaptable Computerized Testing System), enables learn...

In this paper, we address the issues of maintaining sensing coverage and connectivity by keeping a minimum number of sensor nodes in the active mode in wireless sensor networks. We investigate the relationship between coverage and connectivity by solving the following two sub-problems. First, we prove that if the radio range is at least twice the sensing range, complete coverage of a convex are...

Leisure and vacation are generally associated with feelings of relaxation and well-being. However, there is also evidence suggesting that some people feel particularly ill and develop symptoms especially during weekends and vacations. The focal points of this article are the exploration of the antecedents and consequences of this phenomenon, pointing out the need of systematic research on its p...

We study tail asymptotics of the stationary distribution for the GI=G=1-type Markov chain with finitely many background states. Decay rate in the logarithmic sense is identified under a number of conditions on the transition probabilities. The results are applied to the BMAP=G=1 queuewith vacations. The relationship between vacation time and the decay rate of the queue length distribution is in...

The mathematical model of an two-phases-service M/M/1/N queuing system with the server breakdown and multiple vacations was realized and established in the Graduate Employment Services system. Secondly, equations of steady-state probability were derived by applying the Markov process theory. Then, we obtained matrix form solution of steady-state probability by using blocked matrix method. Final...

The performance of a single Bluetooth piconet is analyzed using the theory of M/G/1 queues with vacations. Analytical results for probability distributions of packet access time and service cycle time are derived. Two scheduling policies, limited and exhaustive service, are considered. In general, exhaustive scheduling was found to perform better than limited service. We also discuss the impact...

This article aims to identify how knowledge workers develop their own collaboration strategies and techniques for getting their work done in complex, dynamic knowledge intensive work environments. Three case studies have been conducted to explore the nature of routines in different collaborative working settings as they provide sufficient detail to better understand the actual state and problem...

This paper presents FrameNet’s approach to the representation of Support Verbs, as but one type of multiword expression (MWE) included in the database. In addition to motivating and illustrating FrameNet’s newly consistent annotation practice for Support Verb constructions, the present work advocates adopting a broad view of what constitutes a multiword expression.