a two server queueing system with single and batch service is considered in this paper. the arrival process is assumed to be poisson and the service rate follows an exponential distribution. server-i serves the customers in both single and batch service, while server-ii serves the customers in batch service only. the laplace transform of the transient and steady state behavior of the model is c...

More than 60% of accidents in Iran occur within 30 kilometers of cities entrance roads. Therefore the number of accidents per kilometer in these regions, in contrast to the other parts of roads is very considerable. The city of Tehran, as the capital of Iran, is the cross point of major arterials of passenger and freight transportation. Thus the evaluation of road safety, entering and exiting t...

Background Effect of seasonal changes in human reproduction has been intensively researched. Some studies acknowledge influences of seasonal variation on natural conception, while others can not confirm them. The aim of this study was to investigate the effect of seasonal changes on different stages of assisted reproductive technology (ART) in Tehran. MaterialsAndMethods This study was carried ...

We study isolated vertices and connectivity in the random intersection graphG n,m, p . A Poisson convergence for the number of isolated vertices is determined at the threshold for absence of isolated vertices, which is equivalent to the threshold for connectivity. When m n and α > 6, we give the asymptotic probability of connectivity at the threshold for connectivity. Analogous results are well...

This paper gives a literature review of detection theory and information theory in the Poisson regime, where the channel model is a Poisson point process whose instantaneous rate is controlled by the input. I. Communication under the Poisson Regime In the semi-classical model of photodetection, the output of the photodetector (e.g. a p-i-n diode) is the superposition of two independent Poisson ...

Poisson regression is a popular tool for modeling count data and is applied in a vast array of applications from the social to the physical sciences and beyond. Real data, however, are often overor under-dispersed and, thus, not conducive to Poisson regression. We propose a regression model based on the Conway–Maxwell-Poisson (COM-Poisson) distribution to address this problem. The COM-Poisson r...

BACKGROUND Within longitudinal epidemiological research, 'count' outcome variables with an excess of zeros frequently occur. Although these outcomes are frequently analysed with a linear mixed model, or a Poisson mixed model, a two-part mixed model would be better in analysing outcome variables with an excess of zeros. Therefore, objective of this paper was to introduce the relatively 'new' met...

Count data are pervasive in many areas of risk analysis; deaths, adverse health outcomes, infrastructure system failures, and traffic accidents are all recorded as count events, for example. Risk analysts often wish to estimate the probability distribution for the number of discrete events as part of doing a risk assessment. Traditional count data regression models of the type often used in ris...

vector 0 and variance terms xy. Because the dependent measures, time and frequency, are skewed, they were log-transformed to make them more symmetrically distributed. We note that because of the discrete nature of the frequency data, a linear regression might not be an appropriate model. We therefore also estimated a nonlinear Poisson regression model. However, because using a Poisson specifica...