Coronagraphic Low Order Wave Front Sensor : post-processing sensitivity enhancer for high performance coronagraphs

Detection and characterization of exoplanets by direct imaging requires a coronagraph designed to deliver high contrast at small angular separation. To achieve this, an accurate control of low order aberrations, such as pointing and focus errors, is essential to optimize coronagraphic rejection and avoid the possible confusion between exoplanet light and coronagraphic leaks in the science image. Simulations and laboratory prototyping have shown that a Coronagraphic Low Order Wave-Front Sensor (CLOWFS), using a single defocused image of a reflective focal plane ring, can be used to control tip-tilt to an accuracy of 10^{-3} lambda/D. This paper demonstrates that the data acquired by CLOWFS can also be used in post-processing to calibrate residual coronagraphic leaks from the science image. Using both the CLOWFS camera and the science camera in the system, we quantify the accuracy of the method and its ability to successfully remove light due to low order errors from the science image. We also report the implementation and performance of the CLOWFS on the Subaru Coronagraphic Extreme AO (SCExAO) system and its expected on-sky performance. In the laboratory, with a level of disturbance similar to what is encountered in a post Adaptive Optics beam, CLOWFS post-processing has achieved speckle calibration to 1/300 of the raw speckle level. This is about 40 times better than could be done with an idealized PSF subtraction that does not rely on CLOWFS.Comment: 10 pages, 7 figures, accepted for publication in PAS

Analysis of the copy number profiles of several tumor samples from the same patient reveals the successive steps in tumorigenesis

We present a computational method, TuMult, for reconstructing the sequence of copy number changes driving carcinogenesis, based on the analysis of several tumor samples from the same patient. We demonstrate the reliability of the method with simulated data, and describe applications to three different cancers, showing that TuMult is a valuable tool for the establishment of clonal relationships between tumor samples and the identification of chromosome aberrations occurring at crucial steps in cancer progression

Rapid prototyping of complete systems, the case study of a smart parking

International audienceThis paper details how LINC a coordination middle-ware, can fasten the development of prototypes that integrate several equipment. A case study of rapid prototyping is presented. It illustrates how a smart parking prototype has been built from several independent and autonomous equipment, coming from different vendors. This has been achieved by parallel development thanks to the resource based approach offered by LINC. This paper also describes how LINC helps building rich user interfaces quickly and easily. I. INTRODUCTION Embedded systems have been part of our daily life for decades. Most of the industrial or consumer products embed multiple processors, sensors and actuators. The next step is the opportunity to build new products, systems, and usages, combining together several of these products. In such innovative and quickly evolving context it is necessary to build prototypes to test, validate, and challenge new products usages or solutions. This paper considers prototypes including several equipment, possibly from different vendors. Such prototypes can be used to exhibit demonstrations in a trade fair, to convince investors of the viability of an idea or to verify the adequacy of the solutions for early adopters. To succeed in today's highly competitive market, a prototype should be more than a few items wired together with a command line interface. Targeted prototypes are real-life demonstrations of new products or technologies with a high end-user experience. Moreover, a prototype should be included in its targeted environment (e.g. a house, a building or a parking). The development of prototypes is vital during the validation stage of new products as they may help to

A survey of IoT protocols and their security issues through the lens of a generic IoT stack

International audienceThe Internet of things (IoT) is rapidly growing, and many security issues relate to its wireless technology. These security issues are challenging because IoT protocols are heterogeneous, suit different needs, and are used in different application domains. From this assessment, we identify the need to provide a homogeneous formalism applying to every IoT protocols. In this survey, we describe a generic approach with twofold challenges. The first challenge we tackle is the identification of common principles to define a generic approach to compare IoT protocol stack. We base the comparison on five different criteria: the range, the openness of the protocol, the interoperability, the topology and the security practices of these IoT protocols. The second challenge we consider is to find a generic way to describe fundamental IoT attacks regardless of the protocol used. This approach exposes similar attacks amongst different IoT protocols and is divided into three parts: attacks focusing on packets (passive and active cryptographic attacks), attacks focusing on the protocol (MITM, Flooding, Sybil, Spoofing, Wormhole attacks) and attacks focusing on the whole system (Sinkhole, Selective forwarding attacks). It also highlights which mechanisms are different between two protocols to make both of them vulnerable to an attack. Finally, we draw some lessons and perspectives from this transversal study

IoTMap: A protocol-agnostic multi-layer system to detect application patterns in IoT networks

International audienceThe growth of the Internet of Things (IoT) results in a proliferation of different protocols (ZigBee, Bluetooth, 6LowPAN, Z-Wave, Wi-Fi, etc.). Organizations tend to quickly deploy several IoT applications over time and thus face heterogeneous IoT systems, combining different IoT protocols in different places of the overall system. This heterogeneity of protocols makes these networks hard to monitor or control, and some misconfigurations or unexpected device behaviours may even expose users to security issues. In this work, we propose the IoTMap system. IoTMap models interconnected and heterogeneous IoT networks, combining different protocols, by providing a generic stack and a unified packet format. IoTMap builds an iterative graph model where high-level semantics can progressively be deduced, ranging from packet transmission to application-type analysis. As such, IoTMap detects application behaviours amongst devices implementing different protocols, interconnected through a multi-protocol hub. In its current implementation (available at https://github.com/AlgoSecure/iotmap), IoTMap can inspect Zig- Bee, BLE and 6LowPAN networks

Audit d'un système IoT par test d'intrusion

National audienceL'explosion du secteur de l'Internet des Objets, reposant majoritairement sur des technologies de communication sans fil, soulève de nombreuses problématiques de sécurité. Ceci est notamment dû à leur caractère hétérogène, à leurs réseaux peu cloisonnés et une mise sur le marché hâtive. Nous proposons dans le cadre de cette thèse une méthode permettant d'évaluer la sécurité d'un système d'objets connectés utilisant des modes de communication sans fil, ceci afin de renforcer la sécurité du système d'information dans son ensemble. Notre méthodologie se base sur une approche éprouvée dans l'IT classique : le test d'intrusion

The subaru coronagraphic extreme AO (SCExAO) system: Wavefront control and detection of exoplanets with coherent light modulation in the focal plane

The Subaru Coronagraphic Extreme-AO (SCExAO) system is designed for high contrast coronagraphic imaging at small angular separations, and is scheduled to see first light on the Subam Telescope in early 2011. The wavefront control architecture for SCExAO is optimized for scattered light control and calibration at small angular separations, and is described in this paper. Key subsystems for the SCExAO wavefront control architecture have been successfully demonstrated, and we report results from these tests and discuss their role in the SCExAO system. Among these subsystems, a technique which can calibrate and remove static and slow speckles which traditionally limit high contrast detections is discussed. A visible light lab prototype system at Subam Telescope recently demonstrated speckle halo reduction to 2e-7 contrast within 2 2λ/D, and removal of static coherent speckles to 3e-9 contrast

The Subaru Coronographic Extreme AO (SCExAO) system: Implementation and performances of the Coronographic Low Order WaveFront Sensor

The Subaru Coronagraphic Extreme AO project (SCExAO) is a high performance coronagraph designed to deliver high contrast at small angular separation. For the detection of structures near the diffraction limit, an accurate control of low order wavefront aberrations - tip-tilt and focus - is essential as these aberrations create light leaks that are the source of confusion in the final science image. To address this major difficulty, we have equipped SCExAO with a specially designed Coronagraphic Low Order WaveFront Sensor (CLOWFS) using defocused images of a reflective ring located in the focal plane, that can track tip-tilt errors as small as 10-3?/D. CLOWFS was originally designed to drive actuators in a closed-loop. Here, we show that it can also be used in post-processing to efficiently subtract the tip-tilt induced coronagraphic leaks in the final science image

Phi-score: A cell-to-cell phenotypic scoring method for sensitive and selective hit discovery in cell-based assays

International audiencePhenotypic screening monitors phenotypic changes induced by perturbations, including those generated by drugs or RNA interference. Currently-used methods for scoring screen hits have proven to be problematic, particularly when applied to physiologically relevant conditions such as low cell numbers or inefficient transfection. Here, we describe the Phi-score, which is a novel scoring method for the identification of phenotypic modifiers or hits in cell-based screens. Phi-score performance was assessed with simulations, a validation experiment and its application to gene identification in a large-scale RNAi screen. Using robust statistics and a variance model, we demonstrated that the Phi-score showed better sensitivity, selectivity and reproducibility compared to classical approaches. The improved performance of the Phi-score paves the way for cell-based screening of primary cells, which are often difficult to obtain from patients in sufficient numbers. We also describe a dedicated merging procedure to pool scores from small interfering RNAs targeting the same gene so as to provide improved visualization and hit selection

The Subaru coronagraphic extreme AO (SCExAO) system: Visible imaging mode

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system is an instrument designed to be inserted between the Subaru AO188 system and the infrared HiCIAO camera in order to greatly improve the contrast in the very close (less than 0.5") neighbourhood of stars. Next to the infrared coronagraphic path, a visible scientific path, based on a EMCCD camera, has been implemented. Benefiting from both Adaptive Optics (AO) correction and new data processing techniques, it is a powerful tool for high angular resolution imaging and opens numerous new science opportunities. We propose here a new image processing algorithm, based on the selection of the best signal for each spatial frequency. A factor 2 to 3 in Strehl ratio is obtained compared to the AO long exposure time depending on the image processing algorithm used and the seeing conditions. The system is able to deliver diffraction limited images at 650 nm (17 mas FWHM).We also demonstrate that this approach offers significantly better results than the classical select, shift and add approach (lucky imaging)