Promoteurs immobiliers privés et problématiques de développement durable urbain

At the turn of the century, as the great housing issues – finding homes, building, living differently, reusing thealready built, dealing with crises and constraints – are becoming more acute, new problems have emerged, under thebroader question of sustainable development, and thus questioning the way cities are organised. Therefore, privatereal estate developers are approached over this question, which has become urgent in the wake of the 2007 GrenelleEnvironment conference. From then on, faced with the issues of sustainable development, private contributors tourban construction need to take several scales into account at the same time – housing lot, building, neighbourhood,city – in order to address the many components of sustainability. Private developers first dealt with buildings’energetic treatments and outer structure, but are gradually considering whole sustainable neighbourhoods andcities. This study has focused on fieldwork in two areas : the Ginko eco-neighbourhood in Bordeaux and theconverted Macdonald warehouse. These have enabled us to analyze an understudied area of reasearch, i.e. privatefunding of sustainable neighbourhoods. The birth of sustainable urbanism gives a second life to those two places.It is also an opportunity for private developers to work both in terms of sustainable development, and on the scaleof entire neighbourhoods. This dual aspect, resulting from interests common to public and private actors, enablesreal estate developers to take a truly active part in the rise of sustainable neighbourhoods.Alors même que les grandes priorités de la question du logement (loger, construire et habiter différemment, habiterl’existant, crises et contraintes) tendent à converger et à s’agréger à la charnière du changement de siècle, de nouvellesproblématiques, regroupées sous celle plus globale du développement durable, émergent et (ré)interrogent la productionde la ville. Les promoteurs immobiliers privés sont alors interpellés et mobilisés afin de répondre à cette nouvelleproblématique qui devient même prescription à la suite du Grenelle de l’environnement (2007). Les problématiquesde la durabilité proposent dès lors aux acteurs privés de la fabrique urbaine de se projeter sur une ligne de déclinaisonlogement-bâtiment-quartier-ville et à y opérer des allers-retours afin de répondre à la transversalité des composantes dela durabilité. D’un premier temps consacré au traitement énergétique du bâtiment et de son enveloppe, des promoteursse positionnent peu à peu à l’échelle du quartier durable et de la ville durable. Deux terrains d’études, l’écoquartierbordelais Ginko et la reconversion de l’entrepôt Macdonald, proposent d’éclaircir un pan encore peu approprié parla bibliographie : le portage privé d’opérations de quartiers durables. L’éclosion de l’urbanisme durable ouvre unedeuxième vie à ces deux opérations. Elle ouvre également de nouvelles opportunités aux acteurs privés pouvant opérerun balancement entre les échelles de la durabilité et en mesure de se projeter à l’échelle du quartier. Ce point derencontre, établi par une convergence d’intérêts communs entre acteurs publics et privés, permet alors aux promoteursaménageursde se poser comme force de proposition dans l’édification de quartiers durables

A Natural Steganography Embedding Scheme Dedicated to Color Sensors in the JPEG Domain

International audienceUsing Natural Steganography (NS), a cover raw image acquired at sensitivity ISO 1 is transformed into a stego image whose statistical distribution is similar to a cover image acquired at sensitivity ISO 2 > ISO 1. This paper proposes such an embedding scheme for color sensors in the JPEG domain, extending thus the prior art proposed for the pixel domain and the JPEG domain for monochrome sensors. We first show that color sensors generate strong intra-block and inter-block dependencies between DCT coefficients and that theses dependencies are due to the demosaicking step in the development process. Capturing theses dependencies using an empirical covariance matrix, we propose a pseudo-embedding algorithm on greyscale JPEG images which uses up to four sub-lattices and 64 lattices to embed information while preserving the estimated correlations among DCT coefficients. We then compute an approximation of the average embedding rate w.r.t. the JPEG quality factor and evaluate the empirical security of the proposed scheme for linear and non-linear demosaicing schemes. Our experiments show that we can achieve high capacity (around 2 bit per nzAC) with a high empirical security (P E 30% using DCTR at QF 95)

JPEG Steganography and Synchronization of DCT Coefficients for a Given Development Pipeline

This short paper proposes to use the statistical analysis of the correlation between DCT coefficients to design a new synchronization strategy that can be used for cost-based steganographic schemes in the JPEG domain. First, an analysis is performed on the covariance matrix of DCT coefficients of neighboring blocks after a development similar to the one used to generate BossBase. This analysis exhibits groups of uncorrelated coefficients: 4 groups per block and 2 groups of uncorrelated diagonal neighbors together with groups of mutually correlated coefficients groups of 6 coefficients per blocs and 8 coefficients between 2 adjacent blocks. Using the uncorrelated groups, an embedding scheme can be designed using only 8 disjoint lattices. The cost map for each lattice is updated firstly by using an implicit underlying Gaussian distribution with a variance directly computed from the embedding costs, and secondly by deriving conditional distributions from multivariate distributions. The covariance matrix of these distributions takes into account both the correlations exhibited by the analysis of the covariance matrix and the variance derived from the cost. This synchronization scheme enables to obtain a gain of PE of 5% at QF 95 for an embedding rate close to 0.3 bnzac coefficient using DCTR feature sets

Typologie et représentations des ensembles résidentiels fermés ou sécurisés en France

Cette contribution vise dans un premier temps à réaliser un recensement des programmes fermés avec contrôle des accès en France. Puis, une typologie des ensembles fermés a été mise en œuvre. Enfin, l'article s'oriente vers une étude des représentations qui ont cours à propos des ensembles résidentiels fermés, par une analyse des discours produits par les principaux acteurs concernés par le phénomène : les promoteurs, les résidants de ces complexes fermés et enfin les élus et techniciens en charge de l'urbanisme ou de l'habitat

Biases on the cosmological parameters and thermal SZ residuals

We examine the biases induced on cosmological parameters when the presence of secondary anisotropies is not taken into account in Cosmic Microwave Background analyses. We first develop an exact analytical expression for computing the biases on parameters when any additive signal is neglected in the analysis. We then apply it in the context of the forthcoming Planck experiment. For illustration, we investigate the effect of the sole residual thermal Sunyaev--Zel'dovich signal that remains after cluster extraction. We find in particular that analyses neglecting the presence of this contribution introduce on the cosmological parameters n_s and tau biases, at least 6.5 and 2.9 times their one sigma confidence intervals. The Omega_b parameter is also biased to a lesser extent.Comment: 7 pages, 5 figures, published in MNRA

The ISW-tSZ cross correlation: ISW extraction out of pure CMB data

If Dark Energy introduces an acceleration in the universal expansion then large scale gravitational potential wells should be shrinking, causing a blueshift in the CMB photons that cross such structures (Integrated Sachs-Wolfe effect, [ISW]). Galaxy clusters are known to probe those potential wells. In these objects, CMB photons also experience inverse Compton scattering off the hot electrons of the intra-cluster medium, and this results in a distortion with a characteristic spectral signature of the CMB spectrum (the so-called thermal Sunyaev-Zel'dovich effect, [tSZ]). Since both the ISW and the tSZ effects take place in the same potential wells, they must be spatially correlated. We present how this cross ISW-tSZ signal can be detected in a CMB-data contained way by using the frequency dependence of the tSZ effect in multi frequency CMB experiments like {\it Planck}, {\em without} requiring the use of external large scale structure tracers data. We find that by masking low redshift clusters, the shot noise level decreases significantly, boosting the signal to noise ratio of the ISW--tSZ cross correlation. We also find that galactic and extragalactic dust residuals must be kept at or below the level of ~0.04 muK^2 at l=10, a limit that is a factor of a few below {\it Planck}'s expectations for foreground subtraction. If this is achieved, CMB observations of the ISW-tSZ cross correlation should also provide an independent probe for the existence of Dark Energy and the amplitude of density perturbations.Comment: submitted to MNRA

Ebola Virus Infection: a review on the pharmacokinetic and pharmacodynamic properties of drugs considered for testing in human efficacy trials

International audienceThe 2014-2015 outbreak of Ebola virus disease (EVD) is the largest epidemic to date in terms of number of cases, of death and affected areas. In October 2015, no antiviral agents had proven an antiviral efficacy in patients. However in September 2014 WHO inventoried and regularly updated since then a list of potential drug candidates with demonstrated antiviral efficacy in vitro or in animal models. This includes agents belonging to various therapeutic classes, namely direct antiviral agents (favipiravir and BCX4430), combination of antibodies (ZMapp), type I interferons, RNA interference-based drugs (TKM-Ebola and AVI-7537) and anticoagulant drug (rNAPc2).Here, we review the pharmacokinetic and pharmacodynamic information that are presently available on these drugs, using data obtained in healthy volunteers for pharmacokinetics and data obtained in human clinical trials or animal models for pharmacodynamics. Future studies evaluating these drugs in clinical trials will be critical to confirm their efficacy in humans, propose appropriate doses and evaluate the possibility of treatment combinations

CMB and SZ effect separation with Constrained Internal Linear Combinations

The `Internal Linear Combination' (ILC) component separation method has been extensively used on the data of the WMAP space mission, to extract a single component, the CMB, from the WMAP multifrequency data. We extend the ILC approach for reconstructing millimeter astrophysical emissions beyond the CMB alone. In particular, we construct a Constrained ILC to extract clean maps of both the CMB or the thermal Sunyaev Zeldovich (SZ) effect, with vanishing contamination from the other. The performance of the Constrained ILC is tested on simulations of Planck mission observations, for which we successfully reconstruct independent estimates of the CMB and of the thermal SZ.Comment: 7 pages, 3 figures, submitted to MNRA

Stéganographie naturelle pour images JPEG

International audienc