A discrete-time HOL priority queue with multiple traffic classes.

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Delay Analysis of a Discrete-Time Non-Preemptive Priority Queue with Priority Jumps

In this paper, we consider a discrete-time non-preemptive priority queueing model with priority jumps. Two classes, real-time (high priority) and non-real time (low priority), of traffic will be considered with providing jumps from lower priority traffic to the queue of high priority traffic. We derive expressions for the joint probability generating function of the system contents of the high and the low priority traffic in the steady state and also for some performance measures such as the mean value of the system contents and the packet delay. The behavior of the priority queues with priority jumps will be illustrated by using these results and is compared to the FIFO scheme

Effect of global FCFS and relative load distribution in two-class queues with dedicated servers

In this paper, we investigate multi-class multi-server queueing systems with global FCFS policy, i.e., where customers requiring different types of service— provided by distinct servers— are accommodated in one common FCFS queue. In such scenarios, customers of one class (i.e., requiring a given type of service) may be hindered by customers of other classes. The purpose of this paper is twofold: to gain (qualitative and quantitative) insight into the impact of (i) the global FCFS policy and (ii) the relative distribution of the load amongst the customer classes, on the system performance. We therefore develop and analyze an appropriate discrete-time queueing model with general independent arrivals, two (independent) customer classes and two class-specific servers.We study the stability of the system and derive the system-content distribution at random slot boundaries; we also obtain mean values of the system content and the customer delay, both globally and for each class individually. We then extensively compare these results with those obtained for an analogous system without global FCFS policy (i.e., with individual queues for the two servers). We demonstrate that global FCFS, as well as the relative distribution of the load over the two customer classes, may have a major impact on the system performance

Translanguaging : a matter of sociolinguistics, pedagogics and interaction?

This chapter forms part of an analytical-interpretative exercise in coming to terms with one of the key concepts in contemporary writings on globalization-affected multilingual classrooms: translanguaging (TL). What is the term’s precise scope? What are the theoretical-methodological frameworks which bear upon the formulation of a basis for its implementation? And how can an answer to these two questions be informed by an analysis of instances where TL has been accomplished successfully in classroom practice? As a specific point of departure, we suggest a triadically formulated question: is translanguaging primarily a sociolinguistic, a pedagogical and/or an interactional concept? And, if the conclusion to be drawn is that an affirmative answer is invited for each of the three dimensions, then how might one understand the various interconnections between these dimensions

Low-percentage Ln3+ doping in a tetranuclear lanthanum polyoxometalate assembled from [Mo7O24]6- polyanions yielding visible and near-infrared luminescence

A rare case of low-percentage trivalent lanthanide doping in multinuclear lanthanide polyoxometalates (LnPOMs) was investigated. The [La-4(MoO4) (H2O)(16-) (Mo7O24)(4)](14-) polyanion was chosen as the host material for this study. In this polyanion the central [La-4(MoO4)](10+) core is coordinated by four heptamolybdate groups as well as 16 water molecules. The tetranuclear lanthanum POM was doped with 5% of Eu3+, Tb3+, Sm3+, Dy3+, Nd3+, Er3+, and Yb3+ (according to synthesis), and the structures and luminescence properties of the x%Ln:LaPOMs were investigated. Additionally a series of tetranuclear lanthanide POMs built from [Mo7O24](6-) heptamolybdate polyanions with Eu3+, Tb3+, Sm3+, Dy3+, and Nd3+ instead of La3+ were synthesized, and a detailed analysis revealed that the tetranuclear clusters formed monomers or dimers linked through oxygen bridges. The smaller lanthanide ions, namely, Er3+ and Yb3+, did not form tetranuclear clusters, but instead mononuclear sandwich-type POMs were obtained. The obtained structures were shown to be lanthanide-specific, and not a result of different synthetic/crystallization conditions. The luminescence properties of the x%Ln:LaPOMs were compared with the luminescence properties of the LnPOMs