Availability and maintenance modeling of a batch service queuing system

PurposeThe purpose of the paper is to analyze reliability characteristics of batch service queuing system with a single server model that envisages Poisson input process and exponential service times under first come, first served (FCFS) queue discipline.Design/methodology/approachWith the help of renewal theory and stochastic processes, a model has been designed to discuss the reliability and its characteristics.FindingsThe instantaneous and steady-state availability along with the maintenance model of the systems subject to generalized M/Mb/1 queuing model is derived, and a few particular cases for availability are obtained as well. For supporting the developed model, a case study on electrical distribution system (EDS) has been illustrated, which also includes a comparison for the system subject to M/Mb/1 queuing model and the system without any queue (delay).Originality/valueIt is a quite realistic model that may aid to remove congestion in the system while repairing.

Utilizing Virtualized Hardware Logic Computations to Benefit Multi-User Performance

Recent trends in computer architecture have increased the role of dedicated hardware logic as an effective approach to computation. Virtualization of logic computations (i.e., by sharing a fixed function) provides a means to effectively utilize hardware resources by context switching the logic to support multiple data streams of computation. Multiple applications or users can take advantage of this by using the virtualized computation in an accelerator as a computational service, such as in a software as a service (SaaS) model over a network. In this paper, we analyze the performance of virtualized hardware logic and develop M/G/1 queueing model equations and simulation models to predict system performance. We predict system performance using the queueing model and tune a schedule for optimal performance. We observe that high variance and high load give high mean latency. The simulation models validate the queueing model, predict queue occupancy, show that a Poisson input process distribution (assumed in the queueing model) is reasonable for low load, and expand the set of scheduling algorithms considered.

The properties of the queuing model with the parallel structure

The present article is devoted to research the multi-channelk model with the parallel structure. It means that we consider the model which consists of two infinite-server queues. The service time in the each system has general function of distribution. In this case the stochastic dynamic of our model cannot be defined by Markov chain. As a result, analysis of such models is much more difficult than that of the corresponding Markovian queueing models. Besides we assume that customers arrive to our model according a bivariate Poisson input flow. This input process is characterized by the fact that customers arrive according to a bivariate Poisson flow simultaneously. We consider the number of customers in the systems at time t. This stochastic process describes the state of our model. In present paper we find the limit joint distribution of the number of customers in the systems. In a general way (by differentiating the corresponding generating function.) we obtain the main characteristics of this distribution, such as the expected number of customers in the nodes, its variance and correlation. In the case when parameters of our model dependent on the parameter n (number of series) the limit normal distribution was obtained for the service process in the stationary regime.