Search results for "traffic"

A novel teletraffic-based power saving scheme for cellular networks with microcells

2011

As the number of network components increases to meet the explosion of mobile devices, power conservation has become an important strategy for network operators. In this paper, we propose a novel teletraffic-based approach to save power consumption of a three-cell microcellular network. When the traffic load in the middle cell is lower than certain threshold, the cell can be switched-off and its users will be covered by increasing the transmission power of one sector antenna in each of the two neighboring cells. Numerical results demonstrate that at a moderate cost of increased antenna transmission power of the two sectors, significant amount of network power can be saved for the whole netw…

Multi-resolution quality-based video coding system for DASH scenarios

2021

Today, more than 85% of Internet traffic has a multimedia component. Video streaming occupies a large part of this percentage mainly because this type of content is provided by the most used applications on the Internet (e.g. Twitch, TikTok, Disney+, YouTube, Netflix, etc.). Most of these platforms use HTTP Adaptive Streaming (HAS) to send this media content to end users in order to ensure a good quality of experience (QoE). But, this QoE should be guaranteed from the video to be transmitted, i.e., the video should have an adequate quality by minimizing the bitrate before transmission. In order to solve this issue, we present a system capable of encoding a video in several resolutions given…

Simulation-Based Study to Quantify Data-Communication Benefits in Congested Airport Terminal Area.

2009

TRAFFIC FLOW HYPOTHETICAL MODELLING FOR AIR QUALITY IMPROVEMENT AND PLANNING PURPOSES

2019

The main emphasis of this research was to describe air pollution level and dispersion in a typical street canyon (Valdemara Street in Riga (Latvia) city centre), afterward to postulate potential development scenarios and perform modelling in order to understand the influence on air pollution level. For this purpose special mathematical model was used - Operational Street Pollution Model (OSPM), which was developed by the National Environmental Research Institute in Denmark. Following development scenarios were tested: (1) realistic environmentally friendly - decrease of traffic flow by 50 %, as according to street interviews about 36 - 50 % of drivers are ready to change driving habits from…

Valuing Freight Transport Time using Transport Demand Modelling: A Bibliographical Review

2011

The value of time for freight transport is of major importance in infrastructure-related cost–benefit analysis and yet its study has been largely neglected when compared with its passenger counterpart. In fact, one of the attributes that could decide the profitability of a project is how much can be saved if freight vehicles use new infrastructure. Despite being the primary benefit of most investments in transport infrastructure, researchers have not yet reached agreement over either the size or the nature of the values of time that should be used when evaluating projects. This article provides a review of the estimation of freight value of time through transport demand modelling and extant…

Development of International Freight Transit in Latvia

2013

Abstract International freight transit is transportation of goods through third countries which are neither senders or consumers of the transported freight. International freight transit provides the use of transport infrastructure capacities and the development of transport infrastructure in Latvia, especially in seaports and railways. In Latvia approximately 97% of all transported freight carried by railway is international freight transit. The turnover of Latvia's seaports is approximately 90% international freight transit transport. This paper describes comparative position of Latvia in Logistics Performance Index and assesses international competitiveness of Latvia's international frei…

Environmental Implications of Traffic Flow Delays: A Model for Urban Streets

2012

In this paper the problem of road's capacity is dealt in presence of perturbations of the vehicular flow. In particular, among the different disturbing causes, it is here considered the presence of vehicles parked along the road in relation to their parking activity. Having already established the delay, caused by those vehicles leaving their stationary positions and entering the traffic flow or by those who slow down the flow to park, it is possible to evaluate the changes in time running values. Related to these times delay, the extra pollutant emissions by a given urban running fleet is also evaluated, by utilizing emission factors depending on age, type, volume capacity and engine of th…

Applications to Traffic Breakdown on Highways

2004

During the last years researches into properties of vehicle ensembles on highways form a new branch of physics, called physics of traffic flow. On macroscopic scales the vehicle ensembles exhibit a wide class of phenomena like phase separation and phase transformations widely met in physical systems. Due to the steadily increasing traffic volume in cities and on highways, the mathematical modelling of these phenomena has attracted a great interest. Particularly, the topic of car—following has become of increased importance in traffic engineering and safety research.

Improving performance of roundabout intersections by optimizing traffic-flow speed

2017

Streamlining of urban traffic influence nowadays almost everything about our modern life. The main effect, which we all feel as the daily traffic participants, either as pedestrians or vehicles drivrers, is travel time to work and back. Roundabouts intersections have a number of advantages over intersections with traffic lights, they reduce the severity of accidents, traffic speeds to provide an “calmer” road environment. So, operating performance of roundabouts are complicated, influenced by the confluence operations. The paper aims at analyzing the current situation of traffic in two crowded roundabouts in Sibiu, comparing the results with the original data and proposing solutions to impr…

Transportation noise and risk of stroke: a nationwide prospective cohort study covering Denmark

2021

AbstractBackgroundStudies on transportation noise and incident stroke are few and inconclusive. We aimed to investigate associations between road-traffic and railway noise and the risk of incident stroke in the entire Danish population.MethodsWe estimated road-traffic and railway noise (Lden) at the most and least exposed façades for all residential addresses across Denmark (2.8 million) for the period 1990–2017. Based on this, we estimated the 10-year time-weighted mean noise exposure for 3.6 million Danes aged >35 years, of whom 184 523 developed incident stroke during follow-up from 2000 to 2017. Analyses were conducted using Cox proportional-hazards models, with adjustment for va…