382 research outputs found
Nouveaux métiers, nouveaux enjeux : Quelles compétences pour les ITS coopératifs ?
National audienc
Towards highly adaptable user-centric terminal architecture
International audienceIn the next-generation communication systems, the mobile terminals will be considerably more diverse than nowadays, andthe users will have a greater choice of access technologies,offering different QoS, security, cost, and so on. However, the “best” decision to select an interface and an access network from many other possible combinations has to be taken. This decision will dependon information such as: the user preferences, the requirements from applications, the device capabilities, the performances and capabilities of the available networks, the network operators constraints, etc. Thispaper describes an add-on middleware which deals with interface automatic configuration and selection. Our goal is twofold: to provideusers with “seamless” roaming between heterogeneous access networks,and to allow them to always stay connected through the “best”acces snetwork
Achieving "always best connected" through extensive profile managment
International audienceThe integration of various access networks into a ubiquitous,yet heterogeneous, wireless environment is on the way. This evolution of the mobile network will give the end-user a greater choice of access tech-nologies, and, therefore, the decision to select the “best” interface andaccess network from many possible combinations has to be taken. The decision will depend on information such as: performances and capabilities of the available networks, requirements from applications, user preferences, or network operators’ constraints. Our work focuses on an advanced middleware which deals with profile management to supportthe interface automatic configuration and selection. Furthermore, the proposed mechanism supports the dynamic (re)mapping of the application flows by taking into consideration multiple selection criteri
Les infrastructures de communications
National audienceLes Systèmes de Transport Intelligents coopératifs (C-ITS ) reposent sur des communications sans fil.Quelles infrastructures de communication pour les ITS coopératifs ? Et au-delà de la technologie, quels modèles d’affairespermettront de déployer et d’opérer les infrastructures de communication nécessaires
Technology Integration Framework for Fast and Low Cost Handovers—Case Study: WiFi-WiMAX Network
The Next Generation Wireless Networks (NGWNs) are seemed to be heterogeneous networks based on the integration of several wireless technologies. These networks are required
to achieve performances equivalent to classic wireless networks by ensuring the continuity of communications and the homogeneity of network management during horizontal and vertical handovers. This task is even more important when management services, like security and quality of service (QoS), are deployed at access technology level. In this paper, we propose a framework for heterogeneous wireless technology integration based on network architecture skeleton and a handover management mechanism. This framework optimizes the layer-2 handover procedure to achieve performances required by sensitive applications while ensuring the minimization of signaling overhead required for operated networks. As an application example, we make use of this framework to propose a heterogeneous network based on WiFi and WiMAX technologies. We present an application example of the framework using the specification of a WiFi-WiMAX network. We propose several performance evaluations based on simulation tests based on this application. The latter confirm the efficiency of handover delay optimization and the minimization of management signaling costs
An End-2-End tunnel header compression solution for nested mobile networks
International audience
A training-resistant anomaly detection system
Modern network intrusion detection systems rely on machine learning techniques to detect traffic anomalies and thus intruders. However, the ability to learn the network behaviour in real-time comes at a cost: malicious software can interfere with the learning process, and teach the intrusion detection system to accept dangerous traffic. This paper presents an intrusion detection system (IDS) that is able to detect common network attacks including but not limited to, denial-of-service, bot nets, intrusions, and network scans. With the help of the proposed example IDS, we show to what extent the training attack (and more sophisticated variants of it) has an impact on machine learning based detection schemes, and how it can be detected. © 2018 Elsevier Lt
Optimising QoE for Scalable Video multicast over WLAN
International audienceQuality of Experience (QoE) is the key to success for multimedia applications and perceptual video quality is one of the important component of QoE. A recent video encoding scheme called Scalable Video Coding (SVC) provides the flexibility and the capability to adapt the video quality to varying network conditions and heterogeneous users. In this paper, we focus on SVC multicast over IEEE 802.11 networks. Traditionally, multicast uses the lowest modulation resulting in a video with only base quality even for users with good channel conditions. To optimize QoE, we propose to use multiple multicast sessions with different transmission rates for different SVC layers. The goal is to provide at least the multicast session with acceptable quality to users with bad channel conditions and to provide additional multicast sessions having SVC enhancement layers to users with better channel conditions. The selection of modulation rate for each SVC layer and for each multicast session is achieved with binary integer linear programming depending on network conditions with a goal to maximize global QoE. Results show that our algorithm maximizes global QoE by providing highest quality videos to users with good channel conditions and by guaranteeing at least acceptable QoE for all users
Contribution of image analysis to the description of enzymatic degradation kinetics for particulate food material
International audienceThe objective of the present work was to relate the physical evolution quantified by image analysis to the chemical transformation of beet pulp particles during enzymatic degradation. Beet pulps were degraded into a torus reactor equipped for visualisation. Pectinolytic and cellulolytic enzymes were used separately or in combination. Two global image analysis techniques were tested to characterise the size distribution of overlapping particles. Granulometric curves were extracted by mathematical morphology and a regularisation dimension was assessed by fractal analysis. Both techniques proved efficient to follow particle size evolution during degradation. When using cellulolytic enzymes alone, no chemical or physical evolution was observed. When using pectinolytic enzymes, a chemical modification occurred without any physical evolution. Particles physically disappeared when both enzymes were used. The chemical and physical evolutions of particles during degradation were interpreted taking into account the current model of molecular arrangement of primary cell walls
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