a total of 38, 300 traffic collisions have occurred in tehran, the capital of iran, during 1973. 5, 655 of these collisions in 6, 700 injuries and 560 deaths are selected and discussed. there has been no difference between the accident rates in working and holidays. winter has had the lowest rate, and accidents have been in direct relationship with the crowdedness and heavy traffic periods. nin...

noise pollution can be considered as the most important problem of urban environmental management in mega metropolises and urban transportation is the main source of the mentioned problem. this study aims to investigate the amount of traffic noise dose received by traffic policemen in tehran; district 1 municipality. the investigation was conducted during three consecutive months in 2007 in 282...

background : road runoff is a linear diffuse source of pollution, with very specific pollutant characteristics and ability to discharge into the environment. heavy metal pollution in road runoff has caused widespread concern since the last century. therefore, the purpose of this study was to assess fe, pb, and cd concentrations in surface runoff from regions with high traffic intensity in the c...

We introduce a family of heavy-traffic regimes for large-scale service systems, presenting a range of scalings that include both moderate and extreme heavy traffic, as compared to classical heavy traffic. The heavy-traffic regimes can be translated into capacity sizing rules that lead to economies-of-scales, so that the system utilization approaches 100% while congestion remains limited. We obt...

kamran asgari1, hosein amini2   1- organic farming systems, wageningen university, wageningen, the netherlands   2- faculty of agriculture, khorasgan branch, islamic azad university, isfahan, iran     received: 5 february 2011 accepted: 23 november 2011         *corresponding author: email:[email protected]     abstract   effects of soil and atmosphere pollution on some heavy metals (fe, ...

Recently, heavy-traffic theory has been applied for understanding behavior of delay in switches. The next section explains the heavy traffic scaling. With some toy examples, it discusses how Brownian motion arises in delay analysis and the idea of state-space collapse. Section 2 defines a switch and sketches a standard method for its stability analysis using the fluid scaling. For fluid scaling...

Heavy vehicles have substantial impact on traffic flow particularly during heavy traffic conditions. Large amount of heavy vehicle lane changing manoeuvres may increase the number of traffic accidents and therefore reduce the freeway safety. Improving road capacity and enhancing traffic safety on freeways has been the motivation to establish heavy vehicle lane restriction strategies to reduce t...

Industrial activities and high traffic density are the most important heavy metal pollution sources in urban areas. Roadside dust created by atmospheric deposition can be one of the best indicators for heavy metal contamination levels. The present study reports the spatial distribution patterns and degree of heavy metal pollution (Cd, Cr, Ni, Pb, Zn, and As) in 50 roadside dust samples from urb...

We study the expected delay in a cyclic polling model with mixtures of exhaustive and gated service in heavy traffic. We obtain closed-form expressions for the mean delay under standard heavy-traffic scalings, providing new insights into the behaviour of polling systems in heavy traffic. The results lead to excellent approximations of the expected waiting times in practical heavy-load scenarios...

In this article, modeling in queuing systems with heavy traffic customer flows is reviewed. Key areas include their limiting distributions, asymptotic behaviors, modeling issues and applications. Heavy traffic flows are features of queuing in modern communications, transportation and computer systems today. Initially, we reviewed the onset of asymptotic modeling for heavy traffic single server ...