We observe the statistical properties of blogs that are expected to reflect social human interaction. Firstly, we introduce a basic normalization preprocess that enables us to evaluate the genuine word frequency in blogs that are independent of external factors such as spam blogs, server-breakdowns, increase in the population of bloggers, and periodic weekly behaviors. After this process, we ca...

Modelsandanalyticaltechniquesaredevelopedtoevaluatetheperformanceoftwovariationsof singlebuffers(conventionalandbufferrelaxationsystem)multiplequeuessystem.Intheconventional system,eachqueuecanhaveatmostonecustomeratanytimeandnewlyarrivingcustomersfindthe bufferfullarelost.Inthebufferrelaxationsystem,thequeuebeingservedmayhavetwocusto...

This paper deals with the performance analysis of multiple server retrial queueing systems with a finite number of homogeneous sources of calls, where the heterogeneous servers are subject to random breakdowns and repairs. The requests are serviced according to random and fastest free server disciplines. The novelty of this investigation is the different service rates and different service poli...

Transient analysis of non-Markovian Stochastic Petri nets is a theoretically interesting and practically important problem. We present a new method to compute bounds and an approximation on the average state sojourn times for a special class of deterministic and stochastic Petri nets (DSPNs). In addition to the idea of the subordinated Markov chain traditionally used for the stationary solution...

We consider the MAP/M/c queue with markovian flow of breakdowns. There are K waiting positions for arrival customers in the system. The system we consider comprises c servers, of which one are has to work for the customers. The other servers is in the cold standby , repairing or waiting for repairing, only the working server can fails, and there is only one repairman. This model is quite genera...

This study deals with a single server in the D-policy M/G/1 queueing system in which the server is turned off at the end of each complete period and is activated again only when the cumulative completion times of the customers in the system exceeds a given level D. While the server is working, he is subject to breakdowns according to a Poisson process. When the server breaks down, he requires r...

BACKGROUND Breakdowns in communication and coordination are situations of mismatch between actual and expected conditions in joint activities. Breakdowns have been identified as the leading cause of adverse events in healthcare, especially in the Operating Room environment. As a result, researchers have started to examine breakdowns in healthcare as emergent dynamics of teamwork. However, the o...

In this paper we study a class of open queueing network where servers suffer breakdowns and are subsequently repaired. The network topology is a pipeline with feedback from the final node to the first. Each node consists of a number of queues each with an unreliable server. There are no losses from the queues in this system, however jobs are routed according to the distribution of operational s...

the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract We consider an M [x] /G/1 queue with two types of service subject to random breakdowns having multiple server vacation, where the customers arrive to the system in batches of variable size. We assume that a single server p...

This paper studies a batch arrival single server Bernoulli feedback queue with Poisson arrivals, two stages of heterogeneous service with different (arbitrary) service time distributions subject to random breakdowns and multiple vacations with exponential distributed with Mean vacation time . After first-stage service the server must provide the second stage service. However after the completio...