Search results for " global"

Buckling and nonlinear dynamics of elastically coupled double-beam systems

2016

Abstract This paper deals with damped transverse vibrations of elastically coupled double-beam system under even compressive axial loading. Each beam is assumed to be elastic, extensible and supported at the ends. The related stationary problem is proved to admit both unimodal (only one eigenfunction is involved) and bimodal (two eigenfunctions are involved) buckled solutions, and their number depends on structural parameters and applied axial loads. The occurrence of a so complex structure of the steady states motivates a global analysis of the longtime dynamics. In this regard, we are able to prove the existence of a global regular attractor of solutions. When a finite set of stationary s…

1023 – Therapeutic drug-monitoring of bupropion for depression

2013

Introduction Therapeutic Drug-Monitoring (TDM) for bupropion is limited by bupropion's instability at room temperature and by the absence of a well-defined therapeutic reference range. Further it is unclear to what extent bupropion and its metabolites contribute to therapeutic effects, though hydroxybupropion seems to account for the major antidepressant effects. Aim The aim of this examination was to check if measurement of only hydroxybupropion is useful to guide the antidepressant therapy with bupropion. Methods Hydroxybupropion plasma levels were measured by high performance liquid chromatography with ultra violet detection and related to therapeutic effects measured by the Clinical Glo…

¿Estamos en guerra?

2001

La apoteosis ideológica (2)

2004

Migraciones y progreso

2008

Evaluation of the Impact of Multipath Data Dispersion for Anonymous TCP Connections

2007

Despite recent research efforts, wireless ad hoc networking technology remains especially prone to security attacks. In this work our contribution focuses on determining the optimal trade-off between traffic dispersion and TCP performance to reduce the chances of successful eavesdropping, while maintaining acceptable levels of throughput. For our experiments we propose a multipath-enhanced version of DSR, and we compare Tahoe, Reno and Sack TCP variants. Results show that multipath traffic dispersion impact on TCP throughput is bounded to a maximum of 25-35%, and that there is only a minimal dependence on the number of routes used, the number of consecutive packets sent on each route, the r…

Adaptive Low Priority Packet Marking for Better TCP Performance

2003

This paper proposes a packet marking scheme for TCP traffic. Unlike previous literature work, in our scheme the majority of TCP packets are transmitted as high priority. The role of a low priority packet appears that of a probe, whose goal is to early discover network congestion conditions. Low priority packets are marked according to an adaptive marking algorithm. Numerical results show that our scheme provides improved throughput/delay performance.

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.

Variability and Uncertainty Challenges in Scaling Imaging Spectroscopy Retrievals and Validations from Leaves Up to Vegetation Canopies

2019

Imaging spectroscopy of vegetation requires methods for scaling and generalizing optical signals that are reflected, transmitted and emitted in the solar wavelength domain from single leaves and observed at the level of canopies by proximal sensing, airborne and satellite spectroradiometers. The upscaling embedded in imaging spectroscopy retrievals and validations of plant biochemical and structural traits is challenged by natural variability and measurement uncertainties. Sources of the leaf-to-canopy upscaling variability and uncertainties are reviewed with respect to: (1) implementation of retrieval algorithms and (2) their parameterization and validation of quantitative products through…

¿Cuánto se está calentando el Mediterráneo?. Treinta y cinco años de observaciones desde satélites

2020

El calentamiento global del planeta afecta especialmente a océanos y mares. En el mar Mediterráneo, los registros oceanográficos y meteorológicos tomados in situ junto con las observaciones más recientes desde satélite evidencian un calentamiento global estimado entre 0,6 y 1 ºC durante las tres últimas décadas. En este artículo presentamos los resultados del análisis de una serie de 35 años de imágenes térmicas mensuales en las cuencas occidentales del Mediterráneo. Los datos indican un adelanto e intensificación de la estación estival: los veranos son más largos e intensos y los meses de junio y julio registran las mayores tasas de calentamiento, con incrementos de 0,6 ºC/década.