Search results for "Congestion"
showing 10 items of 79 documents
Viability of new road infrastructure with heterogeneous users
2011
This paper explores the importance of heterogeneity in value of time and route choice when assessing the viability of new road infrastructure to alleviate congestion problems. The model incorporates strategic interaction between road operators in a cost-benefit framework and several competitive regimes are considered. It is then employed to establish the financial and socio-economic viability of a congestion pricing demonstration entering Madrid city centre, where road users have to choose between a free but highly congested road and a priced free-flowing road (semi-private regime). A logit estimation is undertaken with information from a questionnaire among road users in the Eastern Madrid…
The Constraints of Vehicle Range and Congestion for the Use of Electric Vehicles for Urban Freight in France
2015
The 9th International Conference on City Logistics, Tenerife, Espagne, 17-/06/2015 - 19/06/2015; Electric vehicle is a solution to reduce pollutant emissions from road urban freight. This paper assesses the potential CO2 reduction by transferring urban freight from diesel to electric vehicles while simultaneously looking at the two main technical constraints: electric vehicle range and the impact on congestion linked to change diesel heavy duty vehicles (with a load up to 25 tons) to much smaller electric vehicles. The data used has been computed from a survey (ECHO) that describes in details a very large sample of French shipments. Two scenarios were set up, which differ mainly by the type…
Specification and Implementation of Multicast Congestion Control Stair Protocol: Use Case with Multimedia Ubiquitous Networks
2008
Ubiquitous and efficient multicast data delivery service is essential to the success of large-scale group communication applications. In this framework, congestion control through ubiquitous networks is a hot topic for multicast real time protocols. In this paper, authors present specification and implementation of simulate TCP's AIMD with rate-based (STAIR), a multicast congestion control mechanism. Authors have enhanced this approach because they have modeled it using Unified Modeling Language with real time extensions (UML-RT) as a formal specification tool. More to the point point, they introduce a multimedia ubiquitous network which they have used as a reference model to promote their …
Transdermal Nitroglycerine Patch: An Optional Device to Reduce Flap Venous Congestion? A Case Report
2013
ABSTRACT Sometimes in free flap there is a venous congestion without an obstruction of the venous anastomosis or other organic causes of reduction venous drainage (haematoma, seroma compressing the pedicle). In these cases the authors suggest the application of nitroglycerine patch in the congested area of the flap few hours before the surgical exploration of the anastomosis. If there is a fast improvement of the clinical feature of the flap, the surgical exploration could be avoided. The authors underline that applying the nitroglycerin patch should not be regarded in any way as a therapy of a free flap venous thrombosis but only as an useful device, an option to be taken only when the sur…
VIGIL System: A Computer Vision-Based AID System. Evaluation in a Ring Motorway Section in Madrid
1994
Abstract The VIGIL system is an Automatic Incident and Congestion Detection System based on computer vision technology tor motorway applications. VIGIL is constituted by two main modules, the Local Sensor Module and the Central System module. The objective of this paper is to describe the VIGIL Central System functions, mainly the alarm filtering and management capabilities, and to present the field trial currently carried out in Madrid within the ARTIS project (Advanced RTI in Spain) supported by the Tranport Telematic Programme of the EC.
Supporting scalable video transmission in MANETs through distributed admission control mechanisms
2009
Emerging multimedia applications over mobile devices are becoming very popular, especially over infrastructure wireless networks such as cellular and WLANs. However, providing this kind of services over infrastructureless networks like ad hoc networks presents many additional problems. One of these problems is how to share resources fairly among the users involved. In this article we propose a QoS framework supporting scalable video streaming in mobile ad hoc networks based on distributed admission control and video traffic awareness. Our framework promotes fairness between video flows in terms of resource consumption. It also guarantees a significant reduction of the idle times experienced…
L'habitude automobile face à la menace de congestion
2017
National audience; De nombreux travaux récents soulignent la place importante des habitudes dans les pratiques de mobilité quotidienne [Bissell, 2011 ; Brette al., 2014 ; Buhler, 2012, 2015 ; Middleton, 2011 ; Schwanen al., 2012]. Bien que l’habitude renvoie – dans sa définition courante – à une répétition automatique et fréquente de petits gestes sans importance, l’habitude - comme concept scientifique - est en réalité beaucoup plus riche et s’avère pertinent pour décrire la conduite automobile au quotidien en milieu urbain. Le concept d’habitude traduit les savoirfaire intériorisés et incorporés par l’automobiliste qu’il active dans des classes de situations particulières [Hodgson, 2004 ;…
Interference Estimation in IEEE 802.11 Networks
2010
This article describes a technique for distinguishing and quantifying medium access control (MAC) and physical layer (PHY) interference in error-prone 802.11 networks. This technique, is fully distributed, allowing each station to estimate interference individually. The estimator is based on an extended Kalman filter coupled to a mechanism for revealing abrupt changes in state. The network state is a vector of two components, representing PHY interference, expressed in terms of channel-error rate, and MAC interference. Two distinct state models are considered. When PHY interference can be assumed to be constant for all stations, network congestion is expressed by the number of competing ter…
An enhanced TCP congestion avoidance scheme and its performance evaluation in high speed satellite networks
2009
©2009 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE." Article also available from publisher: http://dx.doi.org/10.1109/ICICS.2009.5397691 High speed satellite communication networks are emerging as part of the future global wireless communication systems. However, existing transmission control protocols for satellite networks do not provide satisfactory performance over high speed satellite links due to their ine…
A randomized multicenter trial on a lung ultrasound-guided treatment strategy in patients on chronic hemodialysis with high cardiovascular risk
2021
Lung congestion is a risk factor for all-cause and cardiovascular mortality in patients on chronic hemodialysis, and its estimation by ultrasound may be useful to guide ultrafiltration and drug therapy in this population. In an international, multi-center randomized controlled trial (NCT02310061) we investigated whether a lung ultrasound-guided treatment strategy improved a composite end point (all-cause death, non-fatal myocardial infarction, decompensated heart failure) vs usual care in patients receiving chronic hemodialysis with high cardiovascular risk. Patient-Reported Outcomes (Depression and the Standard Form 36 Quality of Life Questionnaire, SF36) were assessed as secondary outcome…