Search results for "Distributed"
showing 10 items of 1260 documents
Surface plasmon interference fringes in back-reflection
2010
We report the experimental observation of surface plasmon polariton (SPP) interference fringes with near-unity visibility and half-wavelength periodicity obtained in back reflection on a Bragg mirror. The presented method based on leakage radiation microscopy (LRM) represents an alternative solution to optical near-field analysis and opens new ways for the quantitative analysis of SPP fringes. With LRM we investigate various SPP interference patterns and analyze the high reflectivity of Bragg mirror in comparison with theoretical models.
A Lightweight Network Discovery Algorithm for Resource-constrained IoT Devices
2019
Although quite simple, existing protocols for the IoT suffer from the inflexibility of centralized infrastructures and require several configuration stages. The implementation of these protocols is often prohibitive on resource-constrained devices. In this work, we propose a distributed lightweight implementation of network discovery for simple IoT devices. Our approach is based on the exchange of symbolic executable code among nodes. Based on this abstraction, we propose an algorithm that makes even IoT resource-constrained nodes able to construct the network topology graph incrementally and without any a priori information about device positioning and presence. The minimal set of executab…
Collecte des données Véhicule/Environnement et remontée avec réseau Cellulaire et réseau Véhiculaire
2019
Vertical handover is one of the key technologies that will facilitate the connected and autonomous vehicles deployment. Today, the emergence of Vehicular Ad hoc Networks (VANETs): Vehicle-to-Vehicle (V2V) communications, Vehicle-to-Infrastructure (V2I) and Vehicle-to-Everything (V2X) has enabled new applications such as Cooperative Intelligent Transport Systems (C-ITS), real-time applications (for example, autonomous driving), road traffic management applications and comfort applications. However, these networks are characterized by a high level of mobility and dynamic change in the topology, which generates scattered networks and requires handover mechanisms for maintaining ongoing session…
On the coupling between agent internal and agent/ environmental dynamics: Development of spatial representations in evolving autonomous robots
2008
In this article we describe how a population of evolving robots can autonomously develop forms of spatial representation which allow them to self-localize and to discriminate different locations of their environment by integrating sensory-motor information over time. The evolving robots also display a remarkable ability to generalize their skill in new environmental conditions that they have never experienced before. The analysis of the obtained results indicates that the evolved robots come up with simple and robust solutions that exploit quasi-periodic limit cycle dynamics emerging from the coupling between the robot/environmental dynamics and a robot's internal dynamics. More specifical…
Load Demand Analysis of Nordic Rural Area with Holiday Resorts for Network Capacity Planning
2019
Most of the Nordic holiday resorts are in rural area with low capacity distributed network. The rural area network is weak and needs capacity expansion planning as the load demand of this area are going to increase due to penetration of electric vehicles and heat pumps. Such type of rural network can also be operated as a micro-grid, and therefore load analysis is required for appropriate operation. The load analysis will also be useful for finding proper sizing of distributed energy resources including energy storage. In this work, load demand analysis of a typical Nordic holiday resorts, connected in rural grid, is presented to find out the load variation during the usage periods. The loa…
Ontonuts: Reusable Semantic Components for Multi-agent Systems
2009
The volumes of data in information systems are growing drastically. The systems become increasingly complex in trying to handle heterogeneity of ubiquitous components, standards, data formats, etc. According to the vision of Autonomic Computing, the complexity can be handled by introducing self-manageable components able to "run themselves." Agent Technology fits this vision, whereas interoperability among autonomic components can be tackled by Semantic Technologies. The problem of efficient heterogeneous data sharing, exchange and reuse within such systems plays a key role. We present an approach of constructing semantic capabilities (self-descriptive functional components) for software ag…
Specification and Implementation of Multicast Congestion Control Stair Protocol: Use Case with Multimedia Ubiquitous Networks
2008
Ubiquitous and efficient multicast data delivery service is essential to the success of large-scale group communication applications. In this framework, congestion control through ubiquitous networks is a hot topic for multicast real time protocols. In this paper, authors present specification and implementation of simulate TCP's AIMD with rate-based (STAIR), a multicast congestion control mechanism. Authors have enhanced this approach because they have modeled it using Unified Modeling Language with real time extensions (UML-RT) as a formal specification tool. More to the point point, they introduce a multimedia ubiquitous network which they have used as a reference model to promote their …
A Security Framework for Smart Ubiquitous Industrial Resources
2007
Conventional approaches to manage and control security seem to have reached their limits in new complex environments. These environments are open, dynamic, heterogeneous, distributed, self-managing, collaborative, international, nomadic, and ubiquitous. We are currently working on a middleware platform focused on the industrial needs, UBIWARE. UBIWARE integrates Ubiquitous Computing with Semantic Web, Distributed AI, Security and Privacy, and Enterprise Application Integration. In this paper, we describe our long-term vision for the security and privacy management in complex multi-agent systems like UBIWARE, SURPAS. The security infrastructure has to become pervasive, interoperable and inte…
Software Requirements for Ubiquitous Ad Hoc Mobile Networks: An Example of a Bluetooth Application
2009
In contrast with the simple and elegant concept of global computing, also called ubiquitous computing - where daily life objects get now computing capacity and interact among them to provide a wide range of services to users - a major difficulty is arising with the software engineering process to develop applications for these devices. This article discusses the additional parameters that should be taken into account when designing and developing software for ubiquitous devices in ad-hoc networks. In these networks the mobility of the devices could increase the complexity of the requirements to be considered. As a case study, we present a Bluetooth application that has been developed to ful…
Availability in BitTorrent Systems
2007
In this paper, we investigate the problem of highly available, massive-scale file distribution in the Internet. To this end, we conduct a large-scale measurement study of BitTorrent, a popular class of systems that use swarms of actively downloading peers to assist each other in file distribution. The first generation of BitTorrent systems used a central tracker to enable coordination among peers, resulting in low availability due to the tracker's single point of failure. Our study analyzes the prevalence and impact of two recent trends to improve BitTorrent availability: (i) use of multiple trackers, and (ii) use of Distributed Hash Tables (DHTs), both of which also help to balance load be…