Some links between extremum spanning forests,watersheds and min-cuts

Minimum cuts, extremum spanning forests and watersheds have been used as the basis for powerful image segmentation procedures. In this paper, we present some results about the links which exist between these different approaches. Especially, we show that extremum spanning forests are particular cases of watersheds from arbitrary markers and that min-cuts coincide with extremum spanning forests for some particular weight functions.     

Fast and Robust Normal Estimation for Point Clouds with Sharp Features

This paper presents a new method for estimating normals on unorganized point clouds that preserves sharp features. It is based on a robust version of the Randomized Hough Transform (RHT). We consider the filled Hough transform accumulator as an image of the discrete probability distribution of possible normals. The normals we estimate corresponds to the maximum of this distribution. We use a fixed‐size accumulator for speed, statistical exploration bounds for robustness, and randomized accumulators to prevent discretization effects. We also propose various sampling strategies to deal with anisotropy, as produced by laser scans due to differences of incidence. Our experiments show that our approach offers an ideal compromise between precision, speed, and robustness: it is at least as precise and noise‐resistant as state‐of‐the‐art methods that preserve sharp features, while being almost an order of magnitude faster. Besides, it can handle anisotropy with minor speed and precision losses.     

High voltage characterization of tin oxide varistors

High current characterization of SnO₂-based varistors have been carried out and the results obtained have been compared with those ZnO-based commercial surge arresters. It is shown that for a high temperature sintering (1350 °C), the leakage current, breakdown voltage and the saturation at high current density are similar between both types of surge arresters. The paper shows, for the first time, that the high breakdown voltage observed with tin dioxide cannot be easily maintained since the saturation of the ceramics is reached for current densities of several amperes per square centimetre.     

Evolution of cross site request forgery attacks

This paper presents a state of the art of cross-site request forgery (CSRF) attacks and new techniques which can be used by potential intruders to make them more effective. Several attack scenarios on widely used web applications are discussed, and a vulnerability which affect most recent browsers is explained. This vulnerability makes it possible to perform effective CSRF attacks using the XMLHTTPRequest object. In addition, this paper describes a new technique that preserves the malicious code on the target system even after the browser window is closed. Lastly, best solutions to prevent these attacks are discussed to enable everyone (users, browser or Web applications developers, professionals in charge of IT security in an organization or a company) to prevent or manage this threat.     

Disruptive infrared image sensors enabled by quantum dots

Sensors based on quantum dot photodiodes promise quality and accessibility improvement of infrared imaging. We demonstrate miniaturization by sub-2-μm pixel pitch arrays. Functionality is confirmed with external quantum efficiencies above 40% at 1450 nm. Monolithic integration enables high throughput and wide deployment of short-wave infrared (SWIR) imagers in applications that previously could not afford them.     

High accuracy and visibility-consistent dense multiview stereo

Since the initial comparison of Seitz et al., the accuracy of dense multiview stereovision methods has been increasing steadily. A number of limitations, however, make most of these methods not suitable to outdoor scenes taken under uncontrolled imaging conditions. The present work consists of a complete dense multiview stereo pipeline which circumvents these limitations, being able to handle large-scale scenes without sacrificing accuracy. Highly detailed reconstructions are produced within very reasonable time thanks to two key stages in our pipeline: a minimum s-t cut optimization over an adaptive domain that robustly and efficiently filters a quasidense point cloud from outliers and reconstructs an initial surface by integrating visibility constraints, followed by a mesh-based variational refinement that captures small details, smartly handling photo-consistency, regularization, and adaptive resolution. The pipeline has been tested over a wide range of scenes: from classic compact objects taken in a laboratory setting, to outdoor architectural scenes, landscapes, and cultural heritage sites. The accuracy of its reconstructions has also been measured on the dense multiview benchmark proposed by Strecha et al., showing the results to compare more than favorably with the current state-of-the-art methods.     

Robust Estimation for an Inverse Problem Arising in Multiview Geometry

We propose a new approach to the problem of robust estimation for a class of inverse problems arising in multiview geometry. Inspired by recent advances in the statistical theory of recovering sparse vectors, we define our estimator as a Bayesian maximum a posteriori with multivariate Laplace prior on the vector describing the outliers. This leads to an estimator in which the fidelity to the data is measured by the L _??-norm while the regularization is done by the L ₁-norm. The proposed procedure is fairly fast since the outlier removal is done by solving one linear program (LP). An important difference compared to existing algorithms is that for our estimator it is not necessary to specify neither the number nor the proportion of the outliers; only an upper bound on the maximal measurement error for the inliers should be specified. We present theoretical results assessing the accuracy of our procedure, as well as numerical examples illustrating its efficiency on synthetic and real data.     

Argon Attenuates Multiorgan Failure in Relation with HMGB1 Inhibition

Argon inhalation attenuates multiorgan failure (MOF) after experimental ischemic injury. We hypothesized that this protection could involve decreased High Mobility Group Box 1 (HMGB1) systemic release. We investigated this issue in an animal model of MOF induced by aortic cross-clamping. Anesthetized rabbits were submitted to supra-coeliac aortic cross-clamping for 30 min, followed by 300 min of reperfusion. They were randomly divided into three groups (n = 7/group). The Control group inhaled nitrogen (70%) and oxygen (30%). The Argon group was exposed to a mixture of argon (70%) and oxygen (30%). The last group inhaled nitrogen/oxygen (70/30%) with an administration of the HMGB1 inhibitor glycyrrhizin (4 mg/kg i.v.) 5 min before aortic unclamping. At the end of follow-up, cardiac output was significantly higher in Argon and Glycyrrhizin vs. Control (60 ± 4 and 49 ± 4 vs. 33 ± 8 mL/kg/min, respectively). Metabolic acidosis was attenuated in Argon and Glycyrrhizin vs. Control, along with reduced amount of norepinephrine to reverse arterial hypotension. This was associated with reduced interleukin-6 and HMGB1 plasma concentration in Argon and Glycyrrhizin vs. Control. End-organ damages were also attenuated in the liver and kidney in Argon and Glycyrrhizin vs. Control, respectively. Argon inhalation reduced HMGB1 blood level after experimental aortic cross-clamping and provided similar benefits to direct HMGB1 inhibition.     

CMOS pixels for subretinal implantable prothesis

This work reports on the design, fabrication, and characterization of CMOS pixels for subretinal implants, which seems to be an effective way to recover visual capabilities in some types of blindness. Two possible approaches are presented for CMOS pixel implementation: 1) an approach based on a light-controlled oscillator (LICOS) using a ring oscillator with an odd number of inverters and 2) an approach based on distributing a square signal at each pixel that filters out a number of pulses depending of the light intensity wave across the chip (WATCH). Both types of pixels fabricated in 0.35-/spl mu/m CMOS demonstrate good mimic of the electrical behavior of human retina, with low-power consumption (typically 1 mW for a 14/spl times/14 matrix of pixels) and having small dimensions (75/spl times/78.5 /spl mu/m/sup 2/ for LICOS and 70/spl times/50 /spl mu/m/sup 2/ for WATCH), which make them suitable for practical implants. Experimental validation is reported on physiological solutions. Because of its characteristic, the proposed matrix of pixels could be considered as one of the first stand-alone highly integrated solutions for subretinal implant chips.     

A rapid and reliable method for metabolite extraction in yeast using boiling buffered ethanol

A simple and reliable method for the efficient inactivation of metabolism and for quantitative metabolite extraction from yeast cells is presented. It is based on the use of a boiling solution made of 75% ethanol (volume/final volume) buffered with 70 mm-Hepes (final concentration), pH 7·5, to guarantee the stability throughout the whole procedure of a large variety of metabolites, including all glycolytic intermediates, nucleotides, pyridine nucleotides and organic acids compounds. The extraction is fast, requiring only 3 min incubation of yeast cells in the ethanol-buffered mixture maintained at 80°C. It can be carried out either directly by spraying the cells into the boiling mixture, or after quenching the whole culture in 60% methanol kept at −40°C. Extracts are subsequently concentrated by evaporation under partial vacuum and the residue is resuspended in a small volume of water. This concentration step and the use of a highly sensitive analytical method allow us to quantify metabolites in less than 10 mg dry weight cells. This method, which can be applied to other fungi, could be very helpful for the determination of true metabolites in mutants generated through the EUROFAN programme and for metabolic flux analysis. © 1997 John Wiley & Sons, Ltd.