Approches géostrategique et économique de la menace : réponses américaines (Geostrategic and economic approaches of the threat : american answers )

En 2001, le Department of Defense (DoD) des Etats-Unis a décidé de développer un « système de systèmes », désigné sous le nom de Ballistic Missile Defense System (BMDS)1 destiné à protéger les États-Unis contre une attaque limitée de missiles balistiques provenant d’États incertains et la prolifération des armes de destruction massive. Nous explorerons une approche géostratégique et économique des nouvelles menaces et nous examinerons les réponses américaines qui sont fondées sur la réaffirmation de leur statut d’hyper puissance par la maîtrise technologique face à une absence de réponse européenne. 1 Le Système de Défense contre les Missiles Balistiques inclut la Défense Nationale Antimissile (NMD) pour protéger le territoire des États-Unis, et la Défense Antimissile de Théâtre (TMD) pour protéger les forces alliées ou amies déployées sur un théâtre d'opérations militaires. In 2001, the Department of Defense ( DoD) of the United States decided to develop a « system of systems », under the name of Ballistic Missile Defense System ( BMDS)1, intended to protect the United States against limited ballistic missile attacks coming from the rogue States and the proliferation of weapons of mass destruction.. We shall investigate a geo-strategic and economic approach of the new threats and we shall also examine the American answers which are based primarily on the reaffirmation of their status of hyper power by their technological supremacy and the absence of European answer. 1 Ballistic Missile Defense System includes National Missile Defense (NMD), to protect the United States homeland, and Theater Missile Defense (TMD), to protect deployed forces, allies, and friends elsewhere in a theatre of military operations.Géostratégie, défense, Etats-Unis, BMDS/Geostrategy, Defense, USA, BMDS

Clustering with shallow trees

We propose a new method for hierarchical clustering based on the optimisation of a cost function over trees of limited depth, and we derive a message--passing method that allows to solve it efficiently. The method and algorithm can be interpreted as a natural interpolation between two well-known approaches, namely single linkage and the recently presented Affinity Propagation. We analyze with this general scheme three biological/medical structured datasets (human population based on genetic information, proteins based on sequences and verbal autopsies) and show that the interpolation technique provides new insight.Comment: 11 pages, 7 figure

Protention and retention in biological systems

This paper proposes an abstract mathematical frame for describing some features of cognitive and biological time. We focus here on the so called "extended present" as a result of protentional and retentional activities (memory and anticipation). Memory, as retention, is treated in some physical theories (relaxation phenomena, which will inspire our approach), while protention (or anticipation) seems outside the scope of physics. We then suggest a simple functional representation of biological protention. This allows us to introduce the abstract notion of "biological inertia".Comment: This paper was made possible only as part of an extended collaboration with Francis Bailly (see references), a dear friend and "ma\^itre \'a penser", who contributed to the key ideas. Francis passed away in february 2008: we continue here our inspiring discussions and joint wor

Cosmological evolution of scalar fields and gravitino dark matter in gauge mediation at low reheating temperatures

We consider the dynamics of the supersymmetry-breaking scalar field and the production of dark matter gravitinos via its decay in a gauge-mediated supersymmetry breaking model with metastable vacuum. We find that the scalar field amplitude and gravitino density are extremely sensitive to the parameters of the hidden sector. For the case of an O'Raifeartaigh sector, we show that the observed dark matter density can be explained by gravitinos even for low reheating temperatures T_{R} < 10 GeV. Such low reheating temperatures may be implied by detection of the NLSP at the LHC if its thermal freeze-out density is in conflict with BBN.Comment: 11 pages RevTex. Extended discussion and minor corrections, conclusions unaltered. Version to be published in JCA

Terrain surfaces and 3-D landcover classification from small footprint full-waveform lidar data: application to badlands

This article presents the use of new remote sensing data acquired from airborne fullwaveform lidar systems. They are active sensors which record altimeter profiles. This paper introduces a set of methodologies for processing these data. These techniques 5 are then applied to a particular landscape, the badlands, but the methodologies are designed to be applied to any other landscape. Indeed, the knowledge of an accurate topography and a landcover classification is a prior knowledge for any hydrological and erosion model. Badlands tend to be the most significant areas of erosion in the world with the highest erosion rate values. Monitoring and predicting erosion within 10 badland mountainous catchments is highly strategic due to the arising downstream consequences and the need for natural hazard mitigation engineering. Additionaly, beyond the altimeter information, full-waveform lidar data are processed to extract intensity and width of echoes. They are related to the target reflectance and geometry. Wa will investigate the relevancy of using lidar-derived Digital Terrain Models (DTMs) and 15 to investigate the potentiality of the intensity and width information for 3-D landcover classification. Considering the novelty and the complexity of such data, they are presented in details as well as guidelines to process them. DTMs are then validated with field measurements. The morphological validation of DTMs is then performed via the computation of hydrological indexes and photo-interpretation. Finally, a 3-D landcover classification is performed using a Support Vector Machine classifier. The introduction of an ortho-rectified optical image in the classification process as well as full-waveform lidar data for hydrological purposes is then discussed

Very-high-resolution mapping of river-immersed topography by remote sensing

Remote sensing has been used to map river bathymetry for several decades. Non-contact methods are necessary in several cases: inaccessible rivers, large-scale depth mapping, very shallow rivers. The remote sensing techniques used for river bathymetry are reviewed. Frequently, these techniques have been developed for marine environment and have then been transposed to riverine environments. These techniques can be divided into two types: active remote sensing, such as ground penetrating radar and bathymetric lidar; or passive remote sensing, such as through-water photogrammetry and radiometric models. This last technique which consists of finding a logarithmic relationship between river depth and image values appears to be the most used. Fewer references exist for the other techniques, but lidar is an emerging technique. For each depth measurement method, we detail the physical principles and then a review of the results obtained in the field. This review shows a lack of data for very shallow rivers, where a very high spatial resolution is needed. Moreover, the cost related to aerial image acquisition is often huge. Hence we propose an application of two techniques, radiometric models and through-water photogrammetry, with very high-resolution passive optical imagery, light platforms, and off-the-shelf cameras. We show that, in the case of the radiometric models, measurement is possible with a spatial filtering of about 1 m and a homogeneous river bottom. In contrast, with through-water photogrammetry, fine ground resolution and bottom textures are necessary

The Emergence of Interactive Behaviour: A Model of Rational Menu Search

One reason that human interaction with technology is difficult to understand is because the way in which people perform interactive tasks is highly adaptive. One such interactive task is menu search. In the current article we test the hypothesis that menu search is rationally adapted to (1) the ecological structure of interaction, (2) cognitive and perceptual limits, and (3) the goal to maximise the trade-off between speed and accuracy. Unlike in previous models, no assumptions are made about the strategies available to or adopted by users, rather the menu search problem is specified as a reinforcement learning problem and behaviour emerges by finding the optimal policy. The model is tested against existing empirical findings concerning the effect of menu organisation and menu length. The model predicts the effect of these variables on task completion time and eye movements. The discussion considers the pros and cons of the modelling approach relative to other well-known modelling approaches