Search results for "Congestion"
showing 10 items of 79 documents
Use of acetazolamide in the treatment of patients with refractory congestive heart failure
2018
Aims Optimal diuretic treatment of patients with refractory congestive heart failure (CHF) remains to be elucidated. In this work, we aimed to evaluate the serial changes of functional class and surrogates of fluid overload (weight and antigen carbohydrate 125) after addition of oral acetazolamide in patients with refractory CHF. Likewise, serial changes in renal function, serum electrolytes and pH were evaluated. Method This is an observational retrospective study in which 25 ambulatory patients with refractory CHF that received acetazolamide in addition to standard intensive diuretic strategy were evaluated. Longitudinal assessment of New York Heart Association (NYHA) functional class and…
Optimal Paths on Urban Networks Using Travelling Times Prevision
2012
We deal with an algorithm that, once origin and destination are fixed, individuates the route that permits to reach the destination in the shortest time, respecting an assigned maximal travel time, and with risks measure below a given threshold. A fluid dynamic model for road networks, according to initial car densities on roads and traffic coefficients at junctions, forecasts the future traffic evolution, giving dynamical weights to a constrained 𝐾 shortest path algorithm. Simulations are performed on a case study to test the efficiency of the proposed procedure.
Optimal Local Routing Strategies for Community Structured Time Varying Communication Networks
2017
International audience; In time varying data communication networks (TVCN), traffic congestion, system utility maximization and network performance enhancement are the prominent issues. All these issues can be resolved either by optimizing the network structure or by selecting efficient routing approaches. In this paper, we focus on the design of a time varying network model and propose an algorithm to find efficient user route in this network. Centrality plays a very important role in finding congestion free routes. Indeed, the more a node is central, the more it can be congested by the flow coming from or going to its neighborhood. For that reason, classically, routes are chosen such that…
Radio network aspects
2006
Publisher Summary This chapter reviews the mobile radio access network reference scenarios (MORANS)—used to study the performance of the radio cellular networks related to UMTS and the methodologies for the radio network performance evaluation, including the theoretical connectivity models,. It discusses the techniques for radio network optimization such as the packet scheduling for cellular systems or system capacity maximization through the use of multiple antennas. . In order to perform system simulations, reference values for the main parameters characterizing a WCDMA network, are required. MORANS is used for the identification of such parameters. The parameters are classified in two gr…
Inflammation is an amplifier of lung congestion by high lv filling pressure in hemodialysis patients: a longitudinal study
2019
Introduction Since infammation alters vascular permeability, including vascular permeability in the lung, we hypothesized that it can be an amplifer of lung congestion in a category of patients at high risk for pulmonary oedema like end stage kidney disease (ESKD) patients. Objective and methods We investigated the efect modifcation by systemic infammation (serum CRP) on the relationship between a surrogate of the flling pressure of the LV [left atrial volume indexed to the body surface area (LAVI)] and lung water in a series of 220 ESKD patients. Lung water was quantifed by the number of ultrasound B lines (US-B) on lung US. Six-hundred and three recordings were performed during a 2-year f…
FUZZY TCP: A PRELIMINARY STUDY
2002
Implementing efficient TCP for the Internet necessarily has to cope with the problem that the source does not know in advance which window allocation policy should be the best to use for a given network condition. In this paper, an on-line adaptive fuzzy system is used at the source in an objective to find the best possible weighted combination among the available policies.
Efficient Queuing Schemes for HoL-Blocking Reduction in Dragonfly Topologies with Minimal-Path Routing
2015
HPC systems are growing in number of connected endnodes, making the network a main issue in their design. In order to interconnect large systems, dragonfly topologies have become very popular in the latest years as they achieve high scalability by exploiting high-radix switches. However, dragonfly high performance may drop severely due to the Head-of-Line (HoL) blocking effect derived from congestion situations. Many techniques have been proposed for dealing with this harmful effect, the most effective ones being those especially designed for a specific topology and a specific routing algorithm. In this paper we present a queuing scheme called Hierarchical Two-Levels Queuing, designed speci…
Transport Protocols for Remote Programming of Network Robots within the context of Telelaboratories for Education: A Comparative Analysis
2007
Within the context of tele-laboratories for education the use of the Internet as communication media permits any researcher/student to perform remote experiments in a simple and reliable manner. Moreover, this situation introduces many interesting issues like network protocols for Internet robots, the effects of variable bandwidth and time-delays on telerobotics, etc. In this paper we present a comparative analysis of using several Internet transport protocols when performing a remote experiment within the UJI Industrial Telelaboratory. TCP, UDP, Trinomial and TEAR protocols are analyzed using the NS2 simulator. Conclusions show a set of characteristics the authors of this paper consider ve…
Performance Evaluation of CANIT Algorithm in Presence of Congestion Losses
2001
In this paper, we analize by queuing-simulation CANIT (Congestion Avoidance with Normalized Interval of Time) algorithm performances in presence of congestion losses. In a former work [3], we proposed the algorithm (CANIT) for TCP (Transmission Control Protocol) congestion avoidance phase in order to improve fairness during this phase, and we showed that using CANIT algorithm in an environment without loss, instead of standard congestion avoidance algorithm improves both congestion avoidance fairness and bandwith utilization for long RTT connections. In this paper, we consider congestion losses and show that the fairness as well as the bandwith utilization are more efficient when using CANI…
A Novel Multi-hop Broadcasting Method for VANETs Based on Autonomic Computing Paradigm
2014
One of the three best papers, Selected for the Annals of Telecommunications journal; International audience; Broadcasting is widely used in Vehicular Ad hoc Networks (VANETs) but it is hard to achieve efficiently since it depends on the network density, i.e. may cause network congestion if the protocols are not well designed. This paper introduces a novel Autonomic Dissemination Method (ADM) which delivers messages in accordance with given priority and density levels. The proposed approach is based on two steps: an offline optimization process and an online adaptation to the network characteristics. The aim is to make effective use of radio resources when there are many messages to send imu…