Search results for "Telecommunications"
showing 10 items of 1639 documents
TCP Performance in Mobile Ad hoc Networks
2013
International audience; In this paper, we present a survey of TCP (Transmission Control Protocol) protocol for better performance in the MANET (Mobile Ad Hoc Network). After a short presentation of the main features of TCP, we give the most important problems from which TCP suffer in MANET. We present after that some approaches proposed in the literature in order to improve its performance. Our paper contains also a performance evaluation of TCP NewReno and TCP Vegas transport protocols under AODV and DSR routing protocols. The simulations are conducted under varying conditions of number of TCP connections, number of nodes and mobility.
Cadmium mass measurements between the neutron shell closures at N=50 and 82
2010
International audience; The mass values of the neutron-deficient cadmium isotopes 99−109Cd and of the neutronrich isotopes 114,120,122−124,126,128Cd have been measured using ISOLTRAP. The behavior of the separation energies of the cadmium isotopes from N = 50 to 82 is discussed.
Power-Line Communication in Medium-Voltage System: Simulation Model and Onfield Experimental Tests
2012
The aim of this paper is to develop a complete model of a power-line communication (PLC) system operating on a medium-voltage (MV) network. The core-shield configuration was chosen for signal transmission in the power cables. In order to validate the developed model experimental, the medium-voltage network of the Favignana island was used to carry out detailed testing. The transmission was performed between two transformer substations in the presence of mains voltage (i.e., 24 kV). ST7540 FSK power-line transceivers, together with capacitive coupling interfaces, were used for the transmission and the reception of the communication signal. The correlation between the experimental measurement…
Improving Communication in Risk Management of Health Information Technology Systems by means of Medical Text Simplification
2019
Health Information Technology Systems (HITS) are increasingly used to improve the quality of patient care while reducing costs. These systems have been developed in response to the changing models of care to an ongoing relationship between patient and care team, supported by the use of technology due to the increased instance of chronic disease. However, the use of HITS may increase the risk to patient safety and security. While standards can be used to address and manage these risks, significant communication problems exist between experts working in different departments. These departments operate in silos often leading to communication breakdowns. For example, risk management stakeholder…
On the spectral moments of non-WSSUS mobile-to mobile double-Rayleigh fading channels
2017
This paper deals with the mathematical analysis of the spectral moments of non-wide-sensestationary uncorrelated-scattering (non-WSSUS) mobile-to-mobile (M2M) double-Rayleigh fading channels. The point of departure is a recently proposed geometry-based statistical model (GBSM) for M2M double-Rayleigh fading channels from which general analytical expressions are derived for the average Doppler shift, Doppler spread, average delay, and delay spread. Closed-form solutions of such expressions are presented for the particular case of the geometrical two-rings scattering model. The obtained results indicate that the average Doppler shift and Doppler spread are directly influenced by not only the …
Dynamics of Ca2+ and guanosine 5'-[gamma-thio]triphosphate action on insulin secretion from alpha-toxin-permeabilized HIT-T15 cells.
1994
The time course of Ca2+ and GTP-analogue effects on insulin secretion was investigated in HIT-T15 cells permeabilized with Staphylococcus alpha-toxin. These cells responded to Ca2+ in the range 0.1-10 microM and could be used in a dynamic perifusion system because of the minimal run-down of the secretory response. High Ca2+ (10 microM) elicited a monophasic ATP-dependent stimulation of insulin secretion that reached a peak within 5 min (approximately 20-fold increase) and rapidly decreased during the subsequent 15 min to a plateau remaining above basal rates (0.1 microM Ca2+). The decrease in Ca(2+)-induced insulin secretion with time could not be attributed to decreased capacity to respond…
Hypothalamic S-Nitrosylation Contributes to the Counter-Regulatory Response Impairment following Recurrent Hypoglycemia
2013
http://www.ncbi.nlm.nih.gov/pubmed/23894333; International audience; AIMS: Hypoglycemia is a severe side effect of intensive insulin therapy. Recurrent hypoglycemia (RH) impairs the counter-regulatory response (CRR) which restores euglycemia. During hypoglycemia, ventromedial hypothalamus (VMH) production of nitric oxide (NO) and activation of its receptor soluble guanylyl cyclase (sGC) are critical for the CRR. Hypoglycemia also increases brain reactive oxygen species (ROS) production. NO production in the presence of ROS causes protein S-nitrosylation. S-nitrosylation of sGC impairs its function and induces desensitization to NO. We hypothesized that during hypoglycemia, the interaction b…
A Simulation Model of a Tandem Coordinated Supply Chain
2010
This paper presents a study of a coordinated production inventory-system. In the proposed model, any echelon considers its successors as part of its inventory system and generates the replenishment order on the basis of operational information of its partners. We show that the coordinated decision making allows elimination of information distortion along the chain. Furthermore, we show how the bottom-up transmission of inefficiencies, typical of traditional supply chains, is avoided.
An Adaptive Combination of Dark and Bright Channel Priors for Single Image Dehazing
2017
Dehazing methods based on prior assumptions derived from statistical image properties fail when these properties do not hold. This is most likely to happen when the scene contains large bright areas, such as snow and sky, due to the ambiguity between the airlight and the depth information. This is the case for the popular dehazing method Dark Channel Prior. In order to improve its performance, the authors propose to combine it with the recent multiscale STRESS, which serves to estimate Bright Channel Prior. Visual and quantitative evaluations show that this method outperforms Dark Channel Prior and competes with the most robust dehazing methods, since it separates bright and dark areas and …
Channel aggregation with guard-band in D-OFDM based CRNs: Modeling and performance evaluation
2016
Channel aggregation (CA) techniques can offer flexible channel allocation and improve overall system performance in multi-channel cognitive radio networks (CRNs). Although many CA techniques have been proposed and studied, the impact of guard-band on CA for channel access has not been addressed in-depth. In this paper, we study the guard-band allocation mechanisms in discontinuous-orthogonal frequency division multiplexing (D-OFDM) based CRNs, and investigate the impact of guard-band sharing on SU flows when CA is enabled. Continuous time Markov chain (CTMC) based models have been developed in order to investigate the stochastic behavior of PU and SU flows. Based on our mathematical analysi…