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Planification Des Reseaux Locaux Sans Fil Avec Antennes Directionnelles
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Book Synopsis Planification des reseaux locaux sans fil avec antennes directionnelles by : Marc Ouellet
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.
Book Synopsis Modélisation et optimisation de la planification des réseaux locaux sans fil by : Alexandre Gondran
Download or read book Modélisation et optimisation de la planification des réseaux 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.
Book Synopsis Performance Improvement of Ad Hoc Networks Using Directional Antennas and Power Control by :
Download or read book Performance Improvement of Ad Hoc Networks Using Directional Antennas and Power Control written by and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Au cours de la dernière décennie, un intérêt remarquable a été éprouvé en matière des réseaux ad hoc sans fil capables de s'organiser sans soutien des infrastructures. L'utilisation potentielle d'un tel réseau existe dans de nombreux scénarios, qui vont du génie civil et secours en cas de catastrophes aux réseaux de capteurs et applications militaires. La Fonction de coordination distribuée (DCF) du standard IEEE 802.11 est le protocole dominant des réseaux ad hoc sans fil. Cependant, la méthode DCF n'aide pas à profiter efficacement du canal partagé et éprouve de divers problèmes tels que le problème de terminal exposé et de terminal caché. Par conséquent, au cours des dernières années, de différentes méthodes ont été développées en vue de régler ces problèmes, ce qui a entraîné la croissance de débits d'ensemble des réseaux. Ces méthodes englobent essentiellement la mise au point de seuil de détecteur de porteuse, le remplacement des antennes omnidirectionnelles par des antennes directionnelles et le contrôle de puissance pour émettre des paquets adéquatement. Comparées avec les antennes omnidirectionnelles, les antennes directionnelles ont de nombreux avantages et peuvent améliorer la performance des réseaux ad hoc. Ces antennes ne fixent leurs énergies qu'envers la direction cible et ont une portée d'émission et de réception plus large avec la même somme de puissance. Cette particularité peut être exploitée pour ajuster la puissance d'un transmetteur en cas d'utilisation d'une antenne directionnelle. Certains protocoles de contrôle de puissance directionnel MAC ont été proposés dans les documentations. La majorité de ces suggestions prennent seulement la transmission directionnelle en considération et, dans leurs résultats de simulation, ces études ont l'habitude de supposer que la portée de transmission des antennes omnidirectionnelles et directionnelles est la même. Apparemment, cette supposition n'est pas toujours vraie dans les situations réelles. De surcroî
Author :Katia Runser (Auteur d'une thèse en télécommunications (2005)).) Publisher : ISBN 13 : Total Pages :223 pages Book Rating :4.:/5 (492 download)
Book Synopsis Méthodologies pour la planification de réseaux locaux sans-fil by : Katia Runser (Auteur d'une thèse en télécommunications (2005)).)
Download or read book Méthodologies pour la planification de réseaux 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.
Book Synopsis ETUDE ET CONCEPTION D'ANTENNES DIRECTIVES A COMMANDE ELECTRONIQUE POUR RESEAUX LOCAUX SANS FIL HAUT DEBIT by : STEPHANE.. FASSETTA
Download or read book ETUDE ET CONCEPTION D'ANTENNES DIRECTIVES A COMMANDE ELECTRONIQUE POUR RESEAUX LOCAUX SANS FIL HAUT DEBIT written by STEPHANE.. FASSETTA and published by . This book was released on 2000 with total page 207 pages. Available in PDF, EPUB and Kindle. Book excerpt: LA PROBLEMATIQUE DES NOUVEAUX MOYENS DE COMMUNICATIONS RADIOMOBILES TELS LA VIDEO-CONFERENCE, LA TELE-OPERATION, LA TELE-MEDECINE HOSPITALIERE, LES RESEAUX LOCAUX OU LES TERMINAUX MULTIMEDIA NOMADES PORTE SUR L'AUGMENTATION DES DEBITS (LIMITES PAR LES ECHOS PARASITES LIES A LA PROPOGATION MULTI-TRAJETS), L'AUTONOMIE, L'AMELIORATION DE LA PORTEE ET LA REDUCTION DE L'ENCOMBREMENT ET DU COUT DES SYSTEMES. EN REPONSE A CES LIMITATIONS, UN EFFORT DE RECHERCHE AU NIVEAU DES STRUCTURES RAYONNANTES A ETE FOURNI ET EST PRESENTE DANS CE MANUSCRIT. DES ANTENNES RESEAUX CIRCULAIRES SECTORISEES ALIMENTEES DE MANIERE NON CONVENTIONNELLE PAR COMMUTATION DE CHARGES REACTIVES SONT ETUDIEES. DANS UN SOUCI D'INTEGRATION ET DE MINIATURISATION, PLUSIEURS TYPES D'ELEMENTS RAYONNANTS (FILIAIRES, 3D, PLANAIRES) SONT UTILISES. LES PRINCIPALES APPLICATIONS VISEES SONT LES RESEAUX LOCAUX SANS FIL HAUT DEBIT (WLAN) SUIVANT LES NORMES HIPERLAN. UNE REFLEXION SUR LA DIVERSITE LARGE BANDE DES RESEAUX SECTORISES EST ENSUITE PROPOSEE, METTANT EN EVIDENCE SA NATURE HYBRIDE (ANGULAIRE/SPATIALE). CETTE INTERPRETATION EST CONFIRMEE PAR LE CALCUL DU CENTRE DE PHASE DE CES RESEAUX. UNE COMPARAISON ENTRE LES COEFFICIENTS DE CORRELATION INTER-SECTEURS THEORIQUES, DETERMINES A L'AIDE D'UNE HYPOTHESE SUR LES DIRECTIONS D'ARRIVEE DES TRAJETS ET ISSUS DE MESURES DU CANAL DE PROPAGATION EST EFFECTUEE. CE TRAVAIL PERMET FINALEMENT DE DONNER QUELQUES RECOMMANDATIONS QUAND A LA CONCEPTION DE RESEAUX CIRCULAIRES SECTORISES.
Book Synopsis Dictionary of Building and Civil Engineering by : Don Montague
Download or read book Dictionary of Building and Civil Engineering written by Don Montague and published by Taylor & Francis. This book was released on 1996 with total page 472 pages. Available in PDF, EPUB and Kindle. Book excerpt: This dual-language dictionary lists over 20,000 specialist terms in both French and English, covering architecture, building, engineering and property terms. It meets the needs of all building professionals working on projects overseas. It has been comprehensively researched and compiled to provide an invaluable reference source in an increasingly European marketplace.
Book Synopsis Building Wireless Community Networks by : Rob Flickenger
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 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.
Book Synopsis Thinking Translation by : Sandor Hervey
Download or read book Thinking Translation written by Sandor Hervey and published by Routledge. This book was released on 2002-09-11 with total page 273 pages. Available in PDF, EPUB and Kindle. Book excerpt: Thinking Translation is a comprehensive and revolutionary 20-week course in translation method. It has been fully and successfully piloted at the University of St. Andrews. The course offers a challenging and entertaining approach to the acquisition of translation skills. Translation is presented as a problem-solving discipline. Discussion, examples and a full range of exercise work allows students to acquire the skills necessary for a broad range of translation problems. Thinking Translation draws on a wide range of material from technical texts to poetry and song.
Book Synopsis Multimedia over IP and Wireless Networks by : Mihaela van der Schaar
Download or read book Multimedia over IP and Wireless Networks written by Mihaela van der Schaar and published by Elsevier. This book was released on 2011-07-28 with total page 713 pages. Available in PDF, EPUB and Kindle. Book excerpt: Multimedia over IP and Wireless Networks is an indispensable guide for professionals or researchers working in areas such as networking, communications, data compression, multimedia processing, streaming architectures, and computer graphics. Beginning with a concise overview of the fundamental principles and challenges of multimedia communication and networking, this book then branches off organically to tackle compression and networking next before moving on to systems, wireless multimedia and more advanced topics. The Compression section advises on the best means and methodology to ensure multimedia signal (images, text, audio and data) integrity for transmissions on wireless and wired systems. The Networking section addresses channel protection and performance. In the Systems section, the focus is on streaming media on demand, live broadcast and video and voice's role in real-time communication. Wireless multimedia transmission and Quality of Service issues are discussed in the Wireless Multimedia section. An Advanced Topics section concludes the book with an assortment of topics including Peer-to-Peer multimedia communication and multipath networks. Up-to-date coverage of existing standards for multimedia networking Synergistic tutorial approach reinforces knowledge gained in previous chapters Balanced treatment of audio and video with coverage of end-to-end systems
Book Synopsis Experience and Learning by : Arthur W. Chickering
Download or read book Experience and Learning written by Arthur W. Chickering and published by Transaction Publishers. This book was released on 1977-01-01 with total page 89 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :Great Britain: Parliament: House of Commons: Transport Committee Publisher :The Stationery Office ISBN 13 :9780215038319 Total Pages :134 pages Book Rating :4.0/5 (383 download)
Book Synopsis The London Underground and the public-private partnership agreements by : Great Britain: Parliament: House of Commons: Transport Committee
Download or read book The London Underground and the public-private partnership agreements written by Great Britain: Parliament: House of Commons: Transport Committee and published by The Stationery Office. This book was released on 2008-01-25 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report from the Transport Committee, examines London Underground and the Public-Private Partnership Agreements. The Government originally announced proposals for modernising the London Underground network system via Public-Private Partnership (PPP) agreements in 1998. Three contracts were drawn up with: (i) Tube Lines for the maintenance and renewal of the Jubilee, Piccadilly and Northern Lines; (ii) with Metronet Rail BVC for the maintenance and renewal of the Bakerloo, Central, Victoria & Waterloo & City Lines; (iii) with Metronet Rail SSL, responsible for the maintenance and renewal of the "sub-surface lines": the Circle, District, Hammersmith & City, Metropolitan & East London Lines. These PPP Agreements, 30 years in duration, were arrangements to maintain, renew and upgrade parts of London Underground by private sector infrastructure companies (Infracos), whilst London Underground is responsible for services to customers. The PPP Agreements also set out a performance-related incentive and penalty scheme to remunerate the Infracos for the improvements they make to the network. In May 2007, Metronet admitted an overspend of £1 billion and was refused access to loan facilities by the banks. It then made a reference to the PPP Arbiter, which in turn triggered an Extraordinary Review (which occurs when extra costs are incurred above the level allowed for the bid). Metronet put in a bid for £551m but the PPP Arbiter provisionally concluded that a sum of £121m was appropriate. Metronet subsequently went into administration on 18 July 2007. The report sets out a number of conclusions and recommendations, including: contracts that were supposed to deliver 35 station upgrades, in fact delivered only 14, 40% of the requirement; stations that were supposed to cost Metronet SSL £2m, cost £7.5m, with only 65% of schedule track renewal accomplished; the Committee criticises the consequences of the imposition of PPP on Transport for London, as a "lamentable state of affairs", with the future of most of London Underground's upgrade and maintenance work in doubt; the Committee states, that the Government should remember the failure of Metronet before it considers entering similar arrangements; that the Government should publish a candid analysis of the events preceding Metronet's collapse and its consequences; the Committee believe that the PPP model was flawed and probably inferior to traditional public-sector management; that the Government needs to prioritise transparency and clarity to taxpayers and ensure that any future contracts result in clear accountability.
Author :Jean Goubault-Larrecq Publisher :Springer Science & Business Media ISBN 13 :9781402003684 Total Pages :448 pages Book Rating :4.0/5 (36 download)
Book Synopsis Proof Theory and Automated Deduction by : Jean Goubault-Larrecq
Download or read book Proof Theory and Automated Deduction written by Jean Goubault-Larrecq and published by Springer Science & Business Media. This book was released on 2001-11-30 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in computer applications has led to a new attitude to applied logic in which researchers tailor a logic in the same way they define a computer language. In response to this attitude, this text for undergraduate and graduate students discusses major algorithmic methodologies, and tableaux and resolution methods. The authors focus on first-order logic, the use of proof theory, and the computer application of automated searches for proofs of mathematical propositions. Annotation copyrighted by Book News, Inc., Portland, OR
Download or read book Curriculum written by Robert S. Zais and published by Addison-Wesley Longman. This book was released on 1976 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Earth Surface Processes, Landforms and Sediment Deposits by : John Bridge
Download or read book Earth Surface Processes, Landforms and Sediment Deposits written by John Bridge and published by Cambridge University Press. This book was released on 2008-05 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A unique, advanced textbook combining sedimentology and geomorphology in a comprehensive and integrated way.
Download or read book Cities at Risk written by Helene Joffe and published by Springer Science & Business Media. This book was released on 2013-03-27 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the major growth of the world’s population over the past century, as well as rapid urbanisation, people increasingly live in crowded cities. This trend is often accompanied by proliferation of poorly built housing, uncontrolled use of land, occupation of unsafe environments and overstretched services. When a natural hazard strikes such a city many people are vulnerable to loss of life and property. This book explores what these people think and feel about the threats that they face. How do they live with perils ranging from earthquakes to monsoons, from floods to hurricanes, in the 21st century? The authors are drawn from a large range of disciplines: Psychology, Engineering, Geography, Anthropology and Urban Planning. They also reflect on how perils are represented in multiple cultures: the United States, Japan, Turkey, Bangladesh, the United Kingdom and New Zealand. The book therefore not only brings to light the ways that different cultures represent natural hazards but also the different ways in which various disciplines write about living with perils in the 21st century. The book is addressed both to researchers and to organizations involved with risk management and risk mitigation.
Book Synopsis Global Warming and Climate Change by : Emma Carlson Berne
Download or read book Global Warming and Climate Change written by Emma Carlson Berne and published by Referencepoint Press. This book was released on 2008 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt: Throughout the world, the cause and impact of global warming and climate change is being passionately debated. While many claim that a climate crisis is imminent if greenhouse gases are not curbed, others argue that the effects have been overblown. Through objective overviews, primary sources, and full-color illustrations, this title will examine What Is Global Warming and Climate Change? What Are the Consequences of Global Warming? What Are the Controversies Surrounding Global Warming? What Are the Solutions for Global Warming?
