Download or read book Mod lisation et optimisation de la planification des r seaux locaux sans fil written by Alexandre Gondran and published by . This book was released on 2008 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Le problème de planification de réseaux WLAN consiste d’une part à positionner et à paramétrer des antennes dans un bâtiment et d’autre part à leur affecter une fréquence afin d’offrir aux clients un accès sans fil au réseau local. Le réseau ainsi construit doit répondre à des critères de couverture et de qualité de service, tout en minimisant le coût financier. Notre modélisation est basée sur le calcul du débit réel offert en chaque point de demande de service du réseau. Nous montrons que ce critère de débit réel permet une modélisation complète de la qualité de service car il unifie les critères habituels de couverture, de gestion des interférences et de capacité. Notre optimisation traite simultanément le problème de placement des points d’accès et le problème d’affectation de fréquences par un algorithme Voisinages Variables Aléatoires VVA : à chaque itération de cette recherche locale le type de voisinage est tiré au hasard. Cet algorithme est très modulaire et permet facilement de combiner les deux sous problèmes (placement et affectation). Ces travaux ont donnée lieu à des collaborations et partenariats industriels : logiciel de planification globale des WLAN avec Orange Labs et solutions de planification séquentielle avec la start-up Trinaps. Enfin nous approfondissons la modélisation du problème en explicitant les liens entre le calcul du débit réel et les SINR. Dans une première étape ; nous montrons que les contraintes de seuil sur les SINR induisent un problème de T-coloration de graphe (condition nécessaire). Pour obtenir une équivalence rendant compte des interférences multiples, une généralisation du problème de T-coloration pour les hypergraphes est introduite. Dans une seconde étape, nous définissons un algorithme déduisant les seuils de SINR à partir des contraintes sur les débits réels. Cette nouvelle modélisation est la base de nos développements futurs.

Download or read book M thodologies pour la planification de r seaux locaux sans fil written by Katia Runser (Auteur d'une thèse en télécommunications (2005)).) and published by . This book was released on 2005 with total page 223 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'objectif du travail présenté dans cette thèse est de proposer une stratégie de planification automatique des réseaux locaux sans-fil de type WiFi en environnement Indoor. Il s'agit de rechercher une ou plusieurs configurations des points d'accès (AP) au réseau garantissant une certaine qualité de service (QoS). La qualité d'une telle stratégie dépend en grande partie du modèle de prédiction de couverture radio utilisé. La première partie de ces travaux a donc été consacrée au développement et à la validation des prédictions de couverture radio du modèle Multi-Resolution Fourier Domain ParFlow (MR-FDPF). Une étape de calibration du modèle nous a permis de définir un paramétrage adéquat du modèle MR-FDPF pour des bâtiments standard, garantissant une erreur quadratique de moins de 5 dB. La seconde partie se concentre sur le problème de planification wLAN. Des critères de couverture radio, de minimisation des interférences, d'optimisation de la bande passante et d'amélioration des services de localisation ont été proposés. Deux heuristiques de recherche basées sur une approche Tabou ont été développées : une heuristique mono-objectif et une heuristique multiobjectif. Ces travaux ont mis en évidence les avantages d'une recherche multiobjectif car elle permet d'obtenir plusieurs solutions appartenant au front de Pareto de l'espace des fonctions associées au problème traité. Chaque solution représente alors un compromis différent entre les critères du problème à résoudre. Le choix de la solution à déployer se fait à posteriori dans l'ensemble limité des 'bonnes' solutions.

Download or read book Mod lisation des moyens de communication locaux de l entreprise apportant une aide la planification de configuration written by Christian Siebel and published by . This book was released on 1995 with total page 232 pages. Available in PDF, EPUB and Kindle. Book excerpt: L'EVOLUTION RAPIDE DES RESEAUX LOCAUX D'ENTREPRISE REND L'UTILISATION DES OUTILS D'AIDE A LA PLANIFICATION INDISPENSABLE AU MAINTIEN D'UN SYSTEME DE COMMUNICATION PERFORMANT ET OPTIMISE AU SEIN DE L'ENTREPRISE. UN ENSEMBLE D'OUTILS SPECIALISES EXISTE D'ORES ET DEJA. CEPENDANT, SON UTILISATION EST LIMITE EN RAISON D'UN MANQUE D'ECHANGE D'INFORMATIONS ENTRE LES DIVERS OUTILS, ET DE L'ABSENCE DE MODELES ADAPTES A DES RESEAUX D'UNE TAILLE DE PLUSIEURS MILLIERS D'ELEMENTS TRANSMETTANT DE PLUS EN PLUS RAPIDEMENT. LES TRAVAUX DEVELOPPES DANS CETTE THESE PORTENT SUR LA MODELISATION DES MOYENS DE COMMUNICATION AU NIVEAU DES COUCHES UN ET DEUX DU MODELE OSI. NOTRE CONTRIBUTION A CONSISTE A MODELISER LE PROCESSUS DE PLANIFICATION, L'OPTIMISATION DE LA TOPOLOGIE, LES COMPOSANTS AINSI QUE LE TRAFIC D'UNE INTERCONNEXION DE RESEAUX LOCAUX. LE MODELE DE PROCESSUS DE PLANIFICATION DEVELOPPE DEGAGE SIX FONCTIONS AUTOMATISABLES AINSI QUE L'ARCHITECTURE D'UN OUTIL D'AIDE A LA PLANIFICATION REPOSANT SUR UNE INFRASTRUCTURE DE COMMUNICATION OUVERTE. LES TRAVAUX MENES SUR LA MODELISATION DE L'OPTIMISATION RESULTENT EN UNE METHODOLOGIE D'OPTIMISATION DE LA TOPOLOGIE D'UN RESEAU CSMA/CD VISANT SOIT A AUGMENTER SOIT A DIMINUER LA CAPACITE DU RESEAU DANS LE BUT DE MINIMISER LE DELAI MOYEN DE TRANSMISSION. CETTE METHODOLOGIE REPOSE SUR L'UTILISATION D'UNE METHODE DE DISCRIMINATION QUE NOUS AVONS PROPOSEE AFIN DE DETERMINER LA TECHNIQUE D'OPTIMISATION A UTILISER (COMBINATOIRE OU HEURISTIQUE). LA TECHNIQUE DE SIMULATION EST UTILISEE POUR EVALUER FINEMENT DES SOLUTIONS DE PLANIFICATION. ELLE S'APPUIE SUR LA MODELISATION DES COMPOSANTS DU SYSTEME QUE NOUS AVONS SPECIFIEE ET REALISEE AINSI QUE SUR UNE MODELISATION DE TRAFICS. L'ETUDE DE MODELISATION DE TRAFICS A MENE A UN MODELE DE CARACTERISATION ET DE CLASSIFICATION DE TRAFICS, UTILISE PAR LA SUITE POUR CREER DES PROFILS. DEUX NOUVEAUX MODELES DE TRAFICS REPOSANT SUR UNE TRACE COMPRIMEE ONT ETE PROPOSES POUR LA GENERATION DE TRAFIC EN RAFALES

Download or read book Les r seaux Wifi et sa planification en environnement indoor written by Nasri Hasni and published by Editions Universitaires Europeennes. This book was released on 2015-02-09 with total page 80 pages. Available in PDF, EPUB and Kindle. Book excerpt: La transmission radio est utilisee dans la communication sans fil des unites mobiles. On distingue habituellement plusieurs categories de reseaux sans fils, selon le perimetre geographique tel que le reseau Wifi qui permet de connecter des ordinateurs a un reseau local ainsi qu'a l'internet. En environnement indoor, l'optimisation des ressources et l'amelioration de signal nous exigent a bien planifier nos equipements, d'ou developper un outil informatique permettant d'assurer ses taches.

Download or read book Planification des reseaux locaux sans fil avec antennes directionnelles written by Marc Ouellet and published by . This book was released on 2007 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem being NP-hard, we propose a two-step tabu search algorithm to obtain good solutions of our model in a reasonable amount of time. The objective of the first step is to obtain a solution that satisfy all the constraints while the second step focuses on optimizing the previously obtained solution in regards to the objective function. A new neighbourhood, based on radio coverage of an access point, allows for a better optimization step compared to previously proposed neighbourhood. The results show that quasi-optimal solutions can be obtained with the proposed approach for real-size instances of the problem. Also, the use of directional antennas allows for a better research of admissible solutions. We believe that the use of our model can save time and money to any network planner.

Download or read book Analyse et optimisation des protocoles d acc s dans les r seaux sans fil ad hoc written by Iskander Banaouas and published by . This book was released on 2012 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dans cette thèse, nous proposons d'étudier les techniques d'accès dans les réseaux sans fil ad hoc en évaluant le gain en performance offert par certaines d'entre elles par rapports aux autres. Il s'agit aussi de modéliser les performances de ces techniques d'accès a travers des modèles mathématiques. Ceci nous permet entre autres d'étudier la sensibilité de tels protocoles a certaines contraintes des réseaux ad hoc. Cette thèse se présente comme suit: D'abord on présente les modèles utilisés afin de décrire le comportement aléatoire de certaines techniques d'accès. Ensuite on applique ces modèles afin de comparer la distribution du rapport signal sur bruit dans les réseaux CSMA et TDMA. On compare ensuite les protocoles d'accès les plus répandues dans les réseaux d'accès, a savoir CSMA et Aloha. On utilise une modélisation de processus de Poisson pour calculer la probabilité de couverture pour Aloha et Aloha slotté. Enfin, on mesure le gain offert par CSMA sur le multiplexage purement statistique des transmissions d'Aloha. CSMA étant le protocole le plus répandue dans les MANETs, cette dernière se trouve exposée à des situations d'inéquité surtout lorsque le réseau est surchargé. On quantifie ce problème d'inéquité en se basant sur une modélisation markovienne. Cette étude nous permet de prévoir les effets de l'inéquité sur des scénarios de déploiement et de proposer des solutions se basant sur l'adaptation des fenêtres de contention pour atténuer ce problème. Enfin, nous étudions l'utilisation d'Aloha dans les réseaux cognitifs. Dans ce contexte, nous montrons comment deux réseaux utilisant Aloha peuvent coexister. Le réseau secondaire doit ne peut perturber le réseau primaire qu'en provoquant une dégradation bornée de celui-ci. On optimise la probabilité de transmission afin de maximiser l'accès Aloha du réseau secondaire.

Download or read book Interconnexion de reseaux locaux modelisation et problemes d optimisation written by G. Bernard and published by . This book was released on 1980 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Neural Networks written by Gérard Dreyfus and published by Springer Science & Business Media. This book was released on 2005-11-25 with total page 509 pages. Available in PDF, EPUB and Kindle. Book excerpt: Neural networks represent a powerful data processing technique that has reached maturity and broad application. When clearly understood and appropriately used, they are a mandatory component in the toolbox of any engineer who wants make the best use of the available data, in order to build models, make predictions, mine data, recognize shapes or signals, etc. Ranging from theoretical foundations to real-life applications, this book is intended to provide engineers and researchers with clear methodologies for taking advantage of neural networks in industrial, financial or banking applications, many instances of which are presented in the book. For the benefit of readers wishing to gain deeper knowledge of the topics, the book features appendices that provide theoretical details for greater insight, and algorithmic details for efficient programming and implementation. The chapters have been written by experts and edited to present a coherent and comprehensive, yet not redundant, practically oriented introduction.

Download or read book Building Wireless Community Networks written by Rob Flickenger and published by "O'Reilly Media, Inc.". This book was released on 2003 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Building Wireless Community Networks is about getting people online using wireless network technology. The 802.11b standard (also known as WiFi) makes it possible to network towns, schools, neighborhoods, small business, and almost any kind of organization. All that's required is a willingness to cooperate and share resources. The first edition of this book helped thousands of people engage in community networking activities. At the time, it was impossible to predict how quickly and thoroughly WiFi would penetrate the marketplace. Today, with WiFi-enabled computers almost as common as Ethernet, it makes even more sense to take the next step and network your community using nothing but freely available radio spectrum. This book has showed many people how to make their network available, even from the park bench, how to extend high-speed Internet access into the many areas not served by DSL and cable providers, and how to build working communities and a shared though intangible network. All that's required to create an access point for high-speed Internet connection is a gateway or base station. Once that is set up, any computer with a wireless card can log onto the network and share its resources. Rob Flickenger built such a network in northern California, and continues to participate in network-building efforts. His nuts-and-bolts guide covers: Selecting the appropriate equipment Finding antenna sites, and building and installing antennas Protecting your network from inappropriate access New network monitoring tools and techniques (new) Regulations affecting wireless deployment (new) IP network administration, including DNS and IP Tunneling (new) His expertise, as well as his sense of humor and enthusiasm for the topic, makes Building Wireless Community Networks a very useful and readable book for anyone interested in wireless connectivity.

Download or read book Glowworm Swarm Optimization written by Krishnanand N. Kaipa and published by Springer. This book was released on 2017-01-10 with total page 265 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive account of the glowworm swarm optimization (GSO) algorithm, including details of the underlying ideas, theoretical foundations, algorithm development, various applications, and MATLAB programs for the basic GSO algorithm. It also discusses several research problems at different levels of sophistication that can be attempted by interested researchers. The generality of the GSO algorithm is evident in its application to diverse problems ranging from optimization to robotics. Examples include computation of multiple optima, annual crop planning, cooperative exploration, distributed search, multiple source localization, contaminant boundary mapping, wireless sensor networks, clustering, knapsack, numerical integration, solving fixed point equations, solving systems of nonlinear equations, and engineering design optimization. The book is a valuable resource for researchers as well as graduate and undergraduate students in the area of swarm intelligence and computational intelligence and working on these topics.

Download or read book FiWi Access Networks written by Martin Maier and published by Cambridge University Press. This book was released on 2011-12-15 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The evolution of broadband access networks toward bimodal fiber-wireless (FiWi) access networks, described in this book, may be viewed as the endgame of broadband access. After discussing the economic impact of broadband access and current worldwide deployment statistics, all the major legacy wireline and wireless broadband access technologies are reviewed. State-of-the-art GPON and EPON fiber access networks are described, including their migration to next-generation systems such as OCDMA and OFDMA PONs. The latest developments of wireless access networks are covered, including VHT WLAN, Gigabit WiMAX, LTE and WMN. The advantages of FiWi access networks are demonstrated by applying powerful network coding, heterogeneous optical and wireless protection, hierarchical frame aggregation, hybrid routing and QoS continuity techniques across the optical-wireless interface. The book is an essential reference for anyone working on optical fiber access networks, wireless access networks or converged FiWi systems.

Download or read book Wireless Hacks written by Rob Flickenger and published by "O'Reilly Media, Inc.". This book was released on 2003 with total page 310 pages. Available in PDF, EPUB and Kindle. Book excerpt: Continuing with the successful Hack Series, this title provides real-world working examples of how to make useful things happen with wireless equipment.

Download or read book Minimization Methods for Non Differentiable Functions written by N.Z. Shor and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years much attention has been given to the development of auto matic systems of planning, design and control in various branches of the national economy. Quality of decisions is an issue which has come to the forefront, increasing the significance of optimization algorithms in math ematical software packages for al,ltomatic systems of various levels and pur poses. Methods for minimizing functions with discontinuous gradients are gaining in importance and the ~xperts in the computational methods of mathematical programming tend to agree that progress in the development of algorithms for minimizing nonsmooth functions is the key to the con struction of efficient techniques for solving large scale problems. This monograph summarizes to a certain extent fifteen years of the author's work on developing generalized gradient methods for nonsmooth minimization. This work started in the department of economic cybernetics of the Institute of Cybernetics of the Ukrainian Academy of Sciences under the supervision of V.S. Mikhalevich, a member of the Ukrainian Academy of Sciences, in connection with the need for solutions to important, practical problems of optimal planning and design. In Chap. I we describe basic classes of nonsmooth functions that are dif ferentiable almost everywhere, and analyze various ways of defining generalized gradient sets. In Chap. 2 we study in detail various versions of the su bgradient method, show their relation to the methods of Fejer-type approximations and briefly present the fundamentals of e-subgradient methods.

Download or read book Innovate Bristol written by Sven Boermeester and published by . This book was released on 2019-12 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Innovate Bristol highlights and celebrates those companies and individuals that are actively working at building a better tomorrow for all. Innovation Ecosystems thrive through the involvement and support of companies and individuals from all industries, which is why the Innovate series not only focuses on the innovators but also those people whom the Innovation Ecosystem, would not be able to thrive without.

Download or read book ICREEC 2019 written by Ahmed Belasri and published by Springer Nature. This book was released on 2020-06-10 with total page 659 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book highlights peer reviewed articles from the 1st International Conference on Renewable Energy and Energy Conversion, ICREEC 2019, held at Oran in Algeria. It presents recent advances, brings together researchers and professionals in the area and presents a platform to exchange ideas and establish opportunities for a sustainable future. Topics covered in this proceedings, but not limited to, are photovoltaic systems, bioenergy, laser and plasma technology, fluid and flow for energy, software for energy and impact of energy on the environment.

Download or read book Statistical Inference for Ergodic Diffusion Processes written by Yury A. Kutoyants and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 493 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first book in inference for stochastic processes from a statistical, rather than a probabilistic, perspective. It provides a systematic exposition of theoretical results from over ten years of mathematical literature and presents, for the first time in book form, many new techniques and approaches.

Download or read book Semiparametric Theory and Missing Data written by Anastasios Tsiatis and published by Springer Science & Business Media. This book was released on 2007-01-15 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book summarizes current knowledge regarding the theory of estimation for semiparametric models with missing data, in an organized and comprehensive manner. It starts with the study of semiparametric methods when there are no missing data. The description of the theory of estimation for semiparametric models is both rigorous and intuitive, relying on geometric ideas to reinforce the intuition and understanding of the theory. These methods are then applied to problems with missing, censored, and coarsened data with the goal of deriving estimators that are as robust and efficient as possible.