Apport de la diversité de polarisation dans le cadre de Radars à Synthèse d'Ouverture spatiaux

Apport de la diversité de polarisation dans le cadre de Radars à Synthèse d'Ouverture spatiaux PDF Author: Patrick Imbo
Publisher:
ISBN:
Category :
Languages : fr
Pages : 153

Get Book Here

Book Description
Dans le domaine spatial, la diversité de polarisation est encore une ressource rare. Les radars spatiaux opérationnels civils actuels, ERS et RADARSAT n'offrent pas cette diversité de polarisation. Leurs émissions et réceptions sont respectivement limitées aux polarisations verticale et horizontale. L'arrivée d'ENVISAT, sans ouvrir la porte à la polarimétrie totale, offre tout de même des perspectives d'utilisation de signatures radar acquises sous différentes configurations de polarisation. Par ailleurs, les missions spatiales de demain (RadarSat2, ALOS, ...) emportent toutes des modes de polarimétrie totale expérimentaux (notée fp pour full polarimetry). La technique polarimétrique spatiale est par conséquent une technique de devenir, pour laquelle les potentialités doivent être précisemment évaluées. Néanmoins, la spécificité des missions spatiales réside dans le fait qu'elles sont par nature moins performantes en termes de résolution géométrique, de bilan de liaison que leurs homologues aéroportés. L'objectif principal de cette étude est de mettre en lumière les possibles compromis à établir entre la réduction de la mesure polarimétrique, et les gains en terme d'architecture des charges utiles radar qui en découlent. On évalue successivement des architectures incohérentes basées sur la réception incohérente de signaux de co- et de cross-polarisation, puis des architectures cohérentes qui se cantonnent à des mesures de co-polarisation. On introduit un mode de visualisation original de la mesure polarimétrique permettant de n'en retenir que le caractère utile (la représentation ITS) [...]

Apport de la diversité de polarisation dans le cadre de Radars à Synthèse d'Ouverture spatiaux

Apport de la diversité de polarisation dans le cadre de Radars à Synthèse d'Ouverture spatiaux PDF Author: Patrick Imbo
Publisher:
ISBN:
Category :
Languages : fr
Pages : 153

Get Book Here

Book Description
Dans le domaine spatial, la diversité de polarisation est encore une ressource rare. Les radars spatiaux opérationnels civils actuels, ERS et RADARSAT n'offrent pas cette diversité de polarisation. Leurs émissions et réceptions sont respectivement limitées aux polarisations verticale et horizontale. L'arrivée d'ENVISAT, sans ouvrir la porte à la polarimétrie totale, offre tout de même des perspectives d'utilisation de signatures radar acquises sous différentes configurations de polarisation. Par ailleurs, les missions spatiales de demain (RadarSat2, ALOS, ...) emportent toutes des modes de polarimétrie totale expérimentaux (notée fp pour full polarimetry). La technique polarimétrique spatiale est par conséquent une technique de devenir, pour laquelle les potentialités doivent être précisemment évaluées. Néanmoins, la spécificité des missions spatiales réside dans le fait qu'elles sont par nature moins performantes en termes de résolution géométrique, de bilan de liaison que leurs homologues aéroportés. L'objectif principal de cette étude est de mettre en lumière les possibles compromis à établir entre la réduction de la mesure polarimétrique, et les gains en terme d'architecture des charges utiles radar qui en découlent. On évalue successivement des architectures incohérentes basées sur la réception incohérente de signaux de co- et de cross-polarisation, puis des architectures cohérentes qui se cantonnent à des mesures de co-polarisation. On introduit un mode de visualisation original de la mesure polarimétrique permettant de n'en retenir que le caractère utile (la représentation ITS) [...]

Biodiversity of Malaria in the World

Biodiversity of Malaria in the World PDF Author: Jean Mouchet
Publisher: John Libbey Eurotext
ISBN:
Category : Medical
Languages : en
Pages : 468

Get Book Here

Book Description
One million dead a Wear, 500 million with the disease, 2.5 billion people at risk : this is the malaria balance sheet in 2007. The distribution and seriousness of the disease depend on the pathogens and vectors involved, as welt as environmental conditions. Of the four parasites (Plasmodium), only P. falciparum kilts although the other three cause debilitating disease with regular relapses and recrudescence. More than fifty species of Anopheles can fulfil the vector rote which is essential in transmission of the parasite between human beings. Climatic factors (temperature and rainfall), the environment and biogeographical particularities dictate the distribution of anopheline species and determine transmission rates. This is why it makes sense to tank about the biodiversity of malaria. Today, more than 90% of deaths from malaria occur in Tropical Africa which is home to only 10% of humanity. Every 30 seconds a child dies from malaria. This continent harbours the most effective vectors (An. gambiae and An. funestus, in particular) and the climate is highly conducive to transmission of the disease. Severe malaria is also seen in forest foci in Southeast Asia, Papua-New Guinea and the Amazon. In the rest of the tropical and subtropical world, P. vivax and/or P malariae cause less severe disease.

Before We Visit the Goddess

Before We Visit the Goddess PDF Author: Chitra Banerjee Divakaruni
Publisher: Simon and Schuster
ISBN: 1476792011
Category : Fiction
Languages : en
Pages : 240

Get Book Here

Book Description
"A new novel from the author of Oleander Girl, a novel in stories, built around crucial moments in the lives of 3 generations of women in an Indian/Indian-American Family"--

Monitoring soils in the environment with remote sensing and gis

Monitoring soils in the environment with remote sensing and gis PDF Author: Richard Escadafal
Publisher: IRD Orstom
ISBN:
Category : Geographic information systems
Languages : fr
Pages : 674

Get Book Here

Book Description
ISSS congress remote sensing

Low Frequency Scattering

Low Frequency Scattering PDF Author: George Dassios
Publisher: Oxford University Press
ISBN: 9780198536789
Category : Language Arts & Disciplines
Languages : en
Pages : 322

Get Book Here

Book Description
Scattering theory deals with the interactions of waves with obstacles in their path, and low frequency scattering occurs when the obstacles involved are very small. This book gives an overview of the subject for graduates and researchers, for the first time unifying the theories covering acoustic, electromagnetic and elastic waves.

Narratives of Fear and Safety

Narratives of Fear and Safety PDF Author: Kaisa Kaukiainen
Publisher:
ISBN: 9789523590144
Category :
Languages : en
Pages : 544

Get Book Here

Book Description
The essays in this edited volume, written in English and French, tackle the intriguing problems of fear and safety by analysing their various meanings and manifestations in literature and other narrative media. The articles bring forth new, cross-cultural interpretations on fear and safety through examining what kinds of genre-specific means of world-making narratives use to express these two affectivities. The articles also show how important it is to study these themes in order to understand challenges in times of global threats, such as the climate crisis, and - to imagine a better future. The main themes of the book are approached from various theoretical perspectives as related to their literary and cultural representations. Recent trends in research, such as affect and risk theory, serve as the basis for the discussion. Many of the articles in the volume discuss apocalyptic and dystopian narratives that currently permeate the entire cultural landscape. Dystopian narratives do not only deal with future threats, such as totalitarianism, technocracy, or environmental disasters, but also suggest alternative ways of being and new hopes in the form of political resistance. The articles in the volume also draw from disciplines such as gender studies and trauma studies to examine the threats posed by collective fears and aggression on individuals' lives and propose ways of coping with fear. These themes are addressed also in articles analysing new adaptations of old myths that retell stories of the past.

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


Magmatism and the Causes of Continental Break-up

Magmatism and the Causes of Continental Break-up PDF Author: Bryan C. Storey
Publisher: Geological Society of America
ISBN:
Category : Science
Languages : en
Pages : 426

Get Book Here

Book Description


Plant Behaviour and Intelligence

Plant Behaviour and Intelligence PDF Author: A. J. Trewavas
Publisher:
ISBN: 0199539545
Category : Intellect
Languages : en
Pages : 305

Get Book Here

Book Description
This book provides a convincing argument for the view that whole cells and whole plants growing in competitive wild conditions show aspects of plant behaviour that can be accurately described as 'intelligent'. Trewavas argues that behaviour, like intelligence, must be assessed within the constraints of the anatomical and physiological framework of the organism in question. The fact that plants do not have centralized nervous systems for example, does not exclude intelligent behaviour. Outside the human dimension, culture is thought largely absent and fitness is the biological property of value. Thus, solving environmental problems that threaten to reduce fitness is another way of viewing intelligent behaviour and has a similar meaning to adaptively variable behaviour. The capacity to solve these problems might be considered to vary in different organisms, but variation does not mean absence. By extending these ideas into a book that allows a critical and amplified discussion, the author hopes to raise an awareness of the concept of purposive behaviour in plants.

Coasts Under Changing Climate: Observations and Modeling

Coasts Under Changing Climate: Observations and Modeling PDF Author: Rafael Almar
Publisher: Frontiers Media SA
ISBN: 288971926X
Category : Science
Languages : en
Pages : 197

Get Book Here

Book Description