Couche logicielle bas niveau efficace pour interface radio à faisceaux agiles

Couche logicielle bas niveau efficace pour interface radio à faisceaux agiles PDF Author: Thomas Soëte
Publisher:
ISBN:
Category :
Languages : fr
Pages : 176

Get Book Here

Book Description
Les travaux présentés dans ce mémoire se placent dans le contexte des réseaux sans fil sans infrastructure (Ad Hoc) impliquant l’utilisation d’antennes sectorielles simples dans le canal radio à 60 GHz. L’antenne est constituée de plusieurs antennes simples, chacune destinée à un secteur particulier et susceptible d’être commutée mécaniquement pour activer un seul secteur. Il est ainsi possible de choisir le secteur d’émission ou de réception des données. Ce type d’antenne souffre néanmoins d’un problème lié à cette commutation mécanique : elle ne peut pas se faire instantanément. À chaque changement de secteur, une petite quantité de temps est perdue, ce qui diminue l’efficacité de l’ensemble. Ce problème est d’autant plus important lorsque le temps de commutation avoisine le temps d’émission d’un paquet : plus de la moitié de la bande passante peut être gâchée. Les solutions de l’état de l’art permettant de supporter les antennes sectorielles ne prennent généralement pas en compte ce temps de commutation et ne sont donc pas adaptées au problème. La thèse défendue est qu’en prenant en compte ce temps de commutation, il est possible de produire une pile protocolaire performante et adaptée à ce type d’antennes. Nous proposons donc une nouvelle pile protocolaire optimisée comprenant les deux couches basses du modèle OSI. Elle reste donc interopérable avec les systèmes actuels.

Couche logicielle bas niveau efficace pour interface radio à faisceaux agiles

Couche logicielle bas niveau efficace pour interface radio à faisceaux agiles PDF Author: Thomas Soëte
Publisher:
ISBN:
Category :
Languages : fr
Pages : 176

Get Book Here

Book Description
Les travaux présentés dans ce mémoire se placent dans le contexte des réseaux sans fil sans infrastructure (Ad Hoc) impliquant l’utilisation d’antennes sectorielles simples dans le canal radio à 60 GHz. L’antenne est constituée de plusieurs antennes simples, chacune destinée à un secteur particulier et susceptible d’être commutée mécaniquement pour activer un seul secteur. Il est ainsi possible de choisir le secteur d’émission ou de réception des données. Ce type d’antenne souffre néanmoins d’un problème lié à cette commutation mécanique : elle ne peut pas se faire instantanément. À chaque changement de secteur, une petite quantité de temps est perdue, ce qui diminue l’efficacité de l’ensemble. Ce problème est d’autant plus important lorsque le temps de commutation avoisine le temps d’émission d’un paquet : plus de la moitié de la bande passante peut être gâchée. Les solutions de l’état de l’art permettant de supporter les antennes sectorielles ne prennent généralement pas en compte ce temps de commutation et ne sont donc pas adaptées au problème. La thèse défendue est qu’en prenant en compte ce temps de commutation, il est possible de produire une pile protocolaire performante et adaptée à ce type d’antennes. Nous proposons donc une nouvelle pile protocolaire optimisée comprenant les deux couches basses du modèle OSI. Elle reste donc interopérable avec les systèmes actuels.

A Frequency Dictionary of French

A Frequency Dictionary of French PDF Author: Deryle Lonsdale
Publisher: Routledge
ISBN: 1135973504
Category : Foreign Language Study
Languages : en
Pages : 974

Get Book Here

Book Description
A Frequency Dictionary of French is an invaluable tool for all learners of French, providing a list of the 5000 most frequently used words in the language. Based on a 23-million-word corpus of French which includes written and spoken material both from France and overseas, this dictionary provides the user with detailed information for each of the 5000 entries, including English equivalents, a sample sentence, its English translation, usage statistics, and an indication of register variation. Users can access the top 5000 words either through the main frequency listing or through an alphabetical index. Throughout the frequency listing there are thematically-organized lists of the top words from a variety of key topics such as sports, weather, clothing, and family terms. An engaging and highly useful resource, the Frequency Dictionary of French will enable students of all levels to get the most out of their study of French vocabulary. Former CD content is now available to access at www.routledge.com/9780415775311 as support material. Designed for use by corpus and computational linguists it provides the full text in a format that researchers can process and turn into suitable lists for their own research work. Deryle Lonsdale is Associate Professor in the Linguistics and English Language Department at Brigham Young University (Provo, Utah). Yvon Le Bras is Associate Professor of French and Department Chair of the French and Italian Department at Brigham Young University (Provo, Utah).

Ultra Wide Band Antennas

Ultra Wide Band Antennas PDF Author: Xavier Begaud
Publisher: John Wiley & Sons
ISBN: 1118586573
Category : Technology & Engineering
Languages : en
Pages : 217

Get Book Here

Book Description
Ultra Wide Band Technology (UWB) has reached a level of maturity that allows us to offer wireless links with either high or low data rates. These wireless links are frequently associated with a location capability for which ultimate accuracy varies with the inverse of the frequency bandwidth. Using time or frequency domain waveforms, they are currently the subject of international standards facilitating their commercial implementation. Drawing up a complete state of the art, Ultra Wide Band Antennas is aimed at students, engineers and researchers and presents a summary of internationally recognized studies.

MIMO

MIMO PDF Author: Alain Sibille
Publisher: Academic Press
ISBN: 0123821959
Category : Technology & Engineering
Languages : es
Pages : 385

Get Book Here

Book Description
Foreword from Arogyaswami Paulraj, Professor (Emeritus), Stanford University (USA) - The first book to show how MIMO principles can be implemented in today's mobile broadband networks and components - Explains and solves some of the practical difficulties that arise in designing and implementing MIMO systems - Both theory and implementation sections are written in the context of the most recent standards: IEEE 802.11n (WiFi); IEEE 802.16 (WIMAX); 4G networks (3GPP/3GPP2, LTE)

Pervasive Mobile and Ambient Wireless Communications

Pervasive Mobile and Ambient Wireless Communications PDF Author: Roberto Verdone
Publisher: Springer Science & Business Media
ISBN: 144712314X
Category : Computers
Languages : en
Pages : 696

Get Book Here

Book Description
Reporting the findings of COST 2100, a major European intergovernmental project, this volume offers system designers a good source of guidelines based on channel characterization and measurement-based modeling, as well as worthwhile ideas for future research.

Principles of Radar and Sonar Signal Processing

Principles of Radar and Sonar Signal Processing PDF Author: Chevalier François Le
Publisher: Artech House
ISBN: 9781608071357
Category : Radar
Languages : en
Pages : 422

Get Book Here

Book Description


Textile Conservation

Textile Conservation PDF Author: Frances Lennard
Publisher: Routledge
ISBN: 1136434755
Category : Social Science
Languages : en
Pages : 337

Get Book Here

Book Description
Textile Conservation: Advances in Practice demonstrates the development in the role and practice of the textile conservator and captures the current diversity of textile conservators’ work. The book focuses on four major factors which have influenced development in textile conservation practice since the 1980s: the changing context, an evolution in the way conservators think about objects, the greater involvement of stakeholders, and technical developments. These are all integral to effective conservation decision-making. • Includes case studies from the UK, USA and mainland Europe and Asia • Assesses the conservation of objects in some of the world’s major cultural institutions • Highly illustrated in full colour to show the effect of conservation in practice Textile Conservation is a reference manual for textile conservators, textile conservation students and museum and heritage professionals.

Metamorphoses

Metamorphoses PDF Author: Emanuele Coccia
Publisher: John Wiley & Sons
ISBN: 1509545689
Category : Philosophy
Languages : en
Pages : 180

Get Book Here

Book Description
We are all fascinated by the mystery of metamorphosis – of the caterpillar that transforms itself into a butterfly. Their bodies have almost nothing in common. They don’t share the same world: one crawls on the ground and the other flutters its wings in the air. And yet they are one and the same life. Emanuele Coccia argues that metamorphosis – the phenomenon that allows the same life to subsist in disparate bodies – is the relationship that binds all species together and unites the living with the non-living. Bacteria, viruses, fungi, plants, animals: they are all one and the same life. Each species, including the human species, is the metamorphosis of all those that preceded it – the same life, cobbling together a new body and a new form in order to exist differently. And there is no opposition between the living and the non-living: life is always the reincarnation of the non-living, a carnival of the telluric substance of a planet – the Earth – that continually draws new faces and new ways of being out of even the smallest particle of its disparate body. By highlighting what joins humans together with other forms of life, Coccia’s brilliant reflection on metamorphosis encourages us to abandon our view of the human species as static and independent and to recognize instead that we are part of a much larger and interconnected form of life.

Early Nineteenth-century Crafts and Trades

Early Nineteenth-century Crafts and Trades PDF Author: Peter Stockham
Publisher: Dover Publications
ISBN:
Category : Antiques & Collectibles
Languages : en
Pages : 204

Get Book Here

Book Description


Handbook of Nonlinear Partial Differential Equations

Handbook of Nonlinear Partial Differential Equations PDF Author: Andrei D. Polyanin
Publisher: CRC Press
ISBN: 1135440816
Category : Mathematics
Languages : en
Pages : 835

Get Book Here

Book Description
The Handbook of Nonlinear Partial Differential Equations is the latest in a series of acclaimed handbooks by these authors and presents exact solutions of more than 1600 nonlinear equations encountered in science and engineering--many more than any other book available. The equations include those of parabolic, hyperbolic, elliptic and other types, and the authors pay special attention to equations of general form that involve arbitrary functions. A supplement at the end of the book discusses the classical and new methods for constructing exact solutions to nonlinear equations. To accommodate different mathematical backgrounds, the authors avoid wherever possible the use of special terminology, outline some of the methods in a schematic, simplified manner, and arrange the equations in increasing order of complexity. Highlights of the Handbook: