When Should I Use Network Emulation?

The design and development of a complex system requires an adequate methodology and efficient instrumental support in order to early detect and correct anomalies in the functional and non-functional properties of the tested protocols. Among the various tools used to provide experimental support for such developments, network emulation relies on real-time production of impairments on real traffic according to a communication model, either realistically or not. This paper aims at simply presenting to newcomers in network emulation (students, engineers, ...) basic principles and practices illustrated with a few commonly used tools. The motivation behind is to fill a gap in terms of introductory and pragmatic papers in this domain. The study particularly considers centralized approaches, allowing cheap and easy implementation in the context of research labs or industrial developments. In addition, an architectural model for emulation systems is proposed, defining three complementary levels, namely hardware, impairment and model levels. With the help of this architectural framework, various existing tools are situated and described. Various approaches for modeling the emulation actions are studied, such as impairment-based scenarios and virtual architectures, real-time discrete simulation and trace-based systems. Those modeling approaches are described and compared in terms of services and we study their ability to respond to various designer needs to assess when emulation is needed

IREEL: remote experimentation with real protocols and applications over emulated network

This paper presents a novel e-learning platform called IREEL. IREEL is a virtual laboratory allowing students to drive experiments with real Internet applications and end-to-end protocols in the context of networking courses. This platform consists in a remote network emulator offering a set of predefined applications and protocol mechanisms. Experimenters configure and control the emulation and the end-systems behavior in order to perform tests, measurements and observations on protocols or applications operating under controlled specific networking conditions. A set of end-to-end mechanisms, mainly focusing on transport and application level protocols, are currently available. IREEL is scalable and easy to use thanks to an ergonomic web interface

Reproductibilité des paramètres posturographiques et spatiotemporels du pas chez les amputés de membre inférieur

Ce travail analyse la reproductibilité de 6 paramètres posturographiques et de 9 spatiotemporels du pas chez l amputé appareillé. La reproductibilité a été mesurée par le calcul du coefficient de variation (CV) sur 6 essais de posturographie et de marche chez 20 sujets amputés d âge moyen 63,1 ans appariés à 20 sujets contrôles. Les résultats montraient une posture plus instable chez l amputé ainsi qu une marche plus lente, des pas plus courts et plus larges, un temps d appui raccourci du côté amputé et un temps d appui bipodal allongé. Chez les patients, la reproductibilité était excellente pour le pourcentage d appui (CV médian= 5%), bonne pour la vitesse du centre de pression (CP ; CV médian= 14,5%) et acceptable pour la distance parcourue par le CP (CV médian= 18% et 15,5%). Chez les patients le pourcentage d appui était plus reproductible que les autres paramètres posturographiques (p=0,001). La reproductibilité était excellente pour les paramètres temporels du pas tels que la vitesse de marche (CV médian= 4,4%), la cadence du pas (CV médian= 2,8%), le temps d appui monopodal sain et amputé (CV médian= 3% et 4%) et le temps d appui bipodal (CV médian= 4%). Le temps d appui bipodal était plus reproductible chez les patients que chez les témoins (CV médian= 6%; p= 0,01). Concernant les paramètres spatiaux, la reproductibilité était excellente pour la longueur des pas sain et amputé (CV= 3,6% et 3%) et bonne pour la largeur des pas (CV médian= 9%). Les patients les plus sévères avaient des paramètres spatiotemporels du pas moins reproductibles. En conclusion, la reproductibilité des principaux paramètres est bonne voire excellente chez l amputé.GRENOBLE1-BU Médecine pharm. (385162101) / SudocSudocFranceF

Desarrollo de un indicador para el seguimiento de los niveles de inundación en humedales Mediterráneos

Los humedales representan ecosistemas sensibles que son objeto de amenazas antropogénicas. En las últimas décadas, los humedales costeros en el Mediterráneo han sufrido presiones considerables por el crecimiento urbano y la intensificación de prácticas agrícolas. Las técnicas de teledetección y Sistemas de Información Geográfica (SIG) son herramientas eficientes que pueden apoyar el seguimiento de humedales costeros del Mediterráneo. Estas técnicas han sido utilizadas para desarrollar un indicador de inundación para apoyar el seguimiento y control de humedales costeros en el sur de Francia. El indicador se basa en series temporales de imágenes del satélite Landsat, que cubren los años 2000, 2007 y 2012; y capas de referencia de usos del suelo para identificar y mapear los niveles de inundación anuales. La metodología combina el uso de índices de vegetación con un árbol de decisión para detectar la masa de agua que cubre los humedales en diferentes fechas dentro de un ciclo anual. Un proceso de validación es implementado para comprobar la fiabilidad del indicador comparándolo con los inventarios de humedales. Los resultados indican que el área de estudio presenta un alto nivel de inundación a lo largo de todo el año. Durante el periodo de estudio, el 40% del área se encuentra permanentemente inundada. El nivel de inundación aumenta hasta el 56- 62% cuando las inundaciones estacionales son consideradas. Los niveles más altos son detectados durante el invierno (lluvias) y en primavera (inundación de campos de arroz). Las comparaciones temporales en los niveles de inundación muestran que hay una tendencia decreciente con los años (62% en 2000; 59% en 2007; y 56% en 2012).Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Breeding biology of the White-headed Duck Oxyura leucocephala at Lake Tonga (Algeria)

The study of the reproductive phenology of the White-headed Duck was carried out at Lake Tonga, a wetland of international importance for the nesting of this species across the Mediterranean basin. The following breeding parameters have been studied in 2007 and 2008 : dates of laying and hatching, clutch size and breeding success. The breeding population was estimated at 78 males and 26 females in 2007 and at 71 males and 22 females in 2008. Laying is recorded during a period of 9 to 11 weeks from late April to mid-July. A brood size of 3.2 ± 1.6 young (n = 17) was recorded in the first year of study and another of 3.9 ± 1.4 young (n = 37) in the second one. Young fledged between late June and early September. The data obtained in this study suggest that the White-headed Duck may be considered as a bird almost constant in terms of life-history traits in AlgeriaLa phénologie de la reproduction de l'Érismature à tête blanche Oxyura leucocephala a été étudiée au lac Tonga, Parc national d'El Kala (Algérie), une zone humide d'importance internationale pour la nidification de l'espèce à l'échelle du bassin Méditerranéen. Les paramètres de la reproduction étudiés durant les années 2007 et 2008 furent les dates et périodes de ponte, la grandeur des nichées, le succès de reproduction et l'envol des jeunes. La population reproductrice a été estimée à 78 mâles et 26 femelles en 2007 et à 71 mâles et 22 femelles en 2008. La ponte s'étale de fin avril à la mi-juillet, sur une période allant de 9 à 11 semaines. La taille des nichées enregistrées fut de 3,2 ± 1,6 canetons (n = l7) pour la première année d'étude et de 3,9 ± 1,4 (n = 37) pour la seconde. L'envol des jeunes a lieu entre fin juin et début septembre. Les données obtenues au cours de cette étude suggèrent que l'Érismature à tête blanche est un oiseau relativement constant en termes de caractéristiques liées à la reproduction en Algérie

Linking Spatial and Temporal Dynamic of Bacterioplankton Communities With Ecological Strategies Across a Coastal Frontal Area

Ocean frontal systems are widespread hydrological features defining the transition zone between distinct water masses. They are generally of high biological importance as they are often associated with locally enhanced primary production by phytoplankton. However, the composition of bacterial communities in the frontal zone remains poorly understood. In this study, we investigate how a coastal tidal front in Brittany (France) structures the free-living bacterioplankton communities in a spatio-temporal survey across four cruises, five stations and three depths. We used 16S rRNA gene surveys to compare bacterial community structures across 134 seawater samples and defined groups of co-varying taxa (modules) exhibiting coherent ecological patterns across space and time. We found that bacterial communities composition was strongly associated with the biogeochemical characteristics of the different water masses and that the front act as an ecological boundary for free-living bacteria. Seasonal variations in primary producers and their distribution in the water column appeared as the most salient parameters controlling heterotrophic bacteria which dominated the free-living community. Different dynamics of modules observed in this environment were strongly consistent with a partitioning of heterotrophic bacterioplankton in oligotroph and copiotroph ecological strategies. Oligotroph taxa, dominated by SAR11 Clade members, were relatively more abundant in low phytoplankton, high inorganic nutrients water masses, while copiotrophs and particularly opportunist taxa such as Tenacibaculum sp. or Pseudoalteromonas sp. reached their highest abundances during the more productive period. Overall, this study shows a remarkable coupling between bacterioplankton communities dynamics, trophic strategies, and seasonal cycles in a complex coastal environment

MAES Service Case: Wetland ecosystem condition mapping (v.1.0)

SWOS Technical publicationThe MAES working group is preparing the workshop on “ecosystem condition mapping” to streamline the efforts done so far with regards to the mapping and assessment of the condition of Europe’s ecosystems. The MAES WG has requested directly to SWOS partners a specific document to support the mapping and assessing wetland ecosystem condition for this workshop. This document shall highlight the different elements to take into account for the mapping and assessment of wetland ecosystems with the aim of supporting Member States and the European Commission in their efforts to better describe the situation of wetland ecosystems in Europe. This document represents the major output of the MAES Service case that shall show how SWOS outputs are useful to support the MAES WG with regards to wetland ecosystem mapping and assessment