1,321 research outputs found

    Defend Data Poisoning Attacks on Voice Authentication

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    With the advances in deep learning, speaker verification has achieved very high accuracy and is gaining popularity as a type of biometric authentication option in many scenes of our daily life, especially the growing market of web services. Compared to traditional passwords, "vocal passwords" are much more convenient as they relieve people from memorizing different passwords. However, new machine learning attacks are putting these voice authentication systems at risk. Without a strong security guarantee, attackers could access legitimate users' web accounts by fooling the deep neural network (DNN) based voice recognition models. In this paper, we demonstrate an easy-to-implement data poisoning attack to the voice authentication system, which can hardly be captured by existing defense mechanisms. Thus, we propose a more robust defense method, called Guardian, which is a convolutional neural network-based discriminator. The Guardian discriminator integrates a series of novel techniques including bias reduction, input augmentation, and ensemble learning. Our approach is able to distinguish about 95% of attacked accounts from normal accounts, which is much more effective than existing approaches with only 60% accuracy

    Faster Eigenvector Computation via Shift-and-Invert Preconditioning

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    We give faster algorithms and improved sample complexities for estimating the top eigenvector of a matrix Σ\Sigma -- i.e. computing a unit vector xx such that xTΣx(1ϵ)λ1(Σ)x^T \Sigma x \ge (1-\epsilon)\lambda_1(\Sigma): Offline Eigenvector Estimation: Given an explicit ARn×dA \in \mathbb{R}^{n \times d} with Σ=ATA\Sigma = A^TA, we show how to compute an ϵ\epsilon approximate top eigenvector in time O~([nnz(A)+dsr(A)gap2]log1/ϵ)\tilde O([nnz(A) + \frac{d*sr(A)}{gap^2} ]* \log 1/\epsilon ) and O~([nnz(A)3/4(dsr(A))1/4gap]log1/ϵ)\tilde O([\frac{nnz(A)^{3/4} (d*sr(A))^{1/4}}{\sqrt{gap}} ] * \log 1/\epsilon ). Here nnz(A)nnz(A) is the number of nonzeros in AA, sr(A)sr(A) is the stable rank, gapgap is the relative eigengap. By separating the gapgap dependence from the nnz(A)nnz(A) term, our first runtime improves upon the classical power and Lanczos methods. It also improves prior work using fast subspace embeddings [AC09, CW13] and stochastic optimization [Sha15c], giving significantly better dependencies on sr(A)sr(A) and ϵ\epsilon. Our second running time improves these further when nnz(A)dsr(A)gap2nnz(A) \le \frac{d*sr(A)}{gap^2}. Online Eigenvector Estimation: Given a distribution DD with covariance matrix Σ\Sigma and a vector x0x_0 which is an O(gap)O(gap) approximate top eigenvector for Σ\Sigma, we show how to refine to an ϵ\epsilon approximation using O(var(D)gapϵ) O(\frac{var(D)}{gap*\epsilon}) samples from DD. Here var(D)var(D) is a natural notion of variance. Combining our algorithm with previous work to initialize x0x_0, we obtain improved sample complexity and runtime results under a variety of assumptions on DD. We achieve our results using a general framework that we believe is of independent interest. We give a robust analysis of the classic method of shift-and-invert preconditioning to reduce eigenvector computation to approximately solving a sequence of linear systems. We then apply fast stochastic variance reduced gradient (SVRG) based system solvers to achieve our claims.Comment: Appearing in ICML 2016. Combination of work in arXiv:1509.05647 and arXiv:1510.0889

    Dynamics of Simplest Chiral Gauge Theories

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    Arguably, the simplest chiral gauge theories are SO(10)\mathrm{SO}(10) with NfN_f fermion fields in the spinor representation {\bf 16}. We study their dynamics using their supersymmetric limits perturbed by an infinitesimal anomaly-mediated supersymmetry breaking as a guide. We predict the theory is gapped for Nf=1,2N_f=1,2, while the SU(Nf)\mathrm{SU}(N_f) global symmetry is broken to SO(Nf)\mathrm{SO}(\mathrm{N}_f) for moderately large Nf3N_f \geq 3.Comment: 7 pages,3 figure

    NH Beverage Alcohol Summit

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    In July of 2016, over seventy-five people attended the NH Beverage Alcohol Summit at the Mt. Washington Hotel in Bretton Woods, New Hampshire. Commercial stakeholders initiated the summit, but attendees included stakeholders across the industry including members of the NH State Legislature, the NH Liquor Commission, the NH Department of Resources and Economic Development, the prevention and treatment community, NH beer distributors, retailers, and manufacturers of beer, wine, and liquor.The purpose was three-fold:1. To discuss priorities for the industry across a variety of viewpoints2. To identify actions for mutual benefit among industry players3. To set the stage for future decisions and growth for positive impact in the NH beverage industr

    Extremal Presentations for Classical Lie Algebras

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    The long-root elements in Lie algebras of Chevalley type have been well studied and can be characterized as extremal elements, that is, elements xx such that the image of (\ad x)^2 lies in the subspace spanned by xx. In this paper, assuming an algebraically closed base field of characteristic not 2, we find presentations of the Lie algebras of classical Chevalley type by means of minimal sets of extremal generators. The relations are described by simple graphs on the sets. For example, for CnC_n the graph is a path of length 2n2n, and for AnA_n the graph is the triangle connected to a path of length n3n-3.Comment: 26 pages, 6 figure

    Establishing disability weights for congenital pediatric surgical conditions: A multi-modal approach

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    __Background:__ Burden of disease (BoD) as measured by Disability-Adjusted Life Years (DALYs) is one of the criteria for priority-setting in health care resource allocation. DALYs incorporate disability weights (DWs), which are currently expert-derived estimates or non-existent for most pediatric surgical conditions. The objective of this study is to establish DWs for a subset of key pediatric congenital anomalies using a range of health valuation metrics with caregivers in both high- and low-resource settings. __Method:__ We described 15 health states to health professionals (physicians, nurses, social workers, and therapists) and community caregivers in Kenya and Canada. The health states summaries were expert- and community-derived, consisting of a narrated description of the disease and a functional profile described in EQ-5D-5 L style. DWs for each health state were elicited using four health valuation exercises (preference ranking, visual analogue scale (VAS), paired comparison (PC), and time trade-off (TTO)). The PC data were anchored internally to the TTO and externally to existing data to yield DWs for each health state on a scale from 0 (health) to 1 (dead). Any differences in DWs between the two countries were analyzed. __Results:__ In total, 154 participants, matched by profession, were recruited from Kijabe, Kenya (n = 78) and Hamilton, Canada (n = 76). Overall calculated DWs for 15 health states ranged from 0.13 to 0.77, with little difference between countries (intra-class coefficient 0.97). However, DWs generated in Kenya for severe hypospadias and undescended testes were higher than Canadian-derived DWs (p = 0.04 and p < 0.003, respectively). __Conclusions:__ We have derived country-specific DWs for pediatric congenital anomalies using several low-cost methods and inter-professional and community caregivers. The TTO-anchored PC method appears best suited for future use. The majority of DWs do not appear to differ significantly between the two cultural contexts and could be used to inform further work of estimating the burden of global pediatric surgical disease. Care should be taken in comparing the DWs obtained in the current study to the existent list of DWs because methodological differences may impact on their compatibility

    Improving Strength Properties of Paper Utilizing Mycelia Fungus

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    Alternatives to the traditional sack grade of paper used for grocery bags was investigated for use in the commercial market. This project investigated the use of mycelium in conjunction with wood-based pulps to produce a structurally enhanced paper sheet. The study included creating and testing a fibrous sheet containing a network of mycelium. Three mycelium types were used: Reishi (Ganoderma Lucidum), Pearl (Pleurotus Ostreatus var. Columbus), and Enoki (Flammulina Velutipes). All three require similar growth conditions but have different growth patterns. Three major trials were run, providing the mycelium with different growth conditions and medium. The first was a simple inoculation. The second was an inoculation of filter paper that was then stored in petri dishes to help reduce the mold growth discovered in the first trial. And the third was an inoculation of pulp slurries that were left to grow before being converted into small sheets. The slurry samples were made with both bleached and unbleached pulp to see if the type of pulp affected the growth. The mechanical properties of the developed materials were evaluated and compared to control samples of each pulp medium. Testing of the mycelium sheets was minimal because of poor growth, mold buildup, and an insubstantial number of samples per trial. Visual inspection under a microscope with 2x magnification and low angle light revealed areas of shiny, hairlike tendrils, protruding off the surface. In some cases, the tendrils appeared to grow over dark mold spots. Under visual inspection only, Pearl had the most clear and substantial growth. After visual inspection, the sheets were tested mechanically in hopes of more sufficient data; the grammage and tensile strength were measured. Strength comparisons were separated based on the inoculation method--inoculated onto pre-formed sheets or added to pulp slurry. The collected data indicated that Reishi grown on bleached pulp was the strongest. In general, inoculated samples of pulp turned out stronger than the original or plain sheets for bleached pulp and weaker for unbleached pulp

    High-Speed Thermographic Analysis of Diesel Injector Nozzle Tip Temperature

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    The temperature of fuel injectors can affect the flow inside nozzles and the subsequent spray and liquid films on the injector tips. These processes are known to impact fuel mixing, combustion and the formation of deposits that can cause engines to go off calibration. However, there is a lack of experimental data for the transient evolution of nozzle temperature throughout engine cycles and the effect of operating conditions on injector tip temperature. Although some measurements of engine surface temperature exist, they have relatively low temporal resolutions and cannot be applied to production injectors due to the requirement for a specialist coating which can interfere with the orifice geometry. To address this knowledge gap, we have developed a high-speed infrared imaging approach to measure the temperature of the nozzle surface inside an optical diesel engine. We investigated ways of increasing the emissivity of the nozzle surface with minimal intrusion by applying thin carbon coatings. We compare our measurements with those from a production injector that was instrumented with internal thermocouples. Our steady-state off-engine investigation showed that nozzle surface temperature measured by infrared imaging could yield data at 1200 fps with uncertainties of #x0002B;20K to -1K compared to simultaneous thermocouple measurements. We applied this approach to an optical diesel engine to investigate the effect of injection duration and increased swirl ratio on injector nozzle temperature and surface homogeneity.</p

    A fruit quality gene map of Prunus

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    <p>Abstract</p> <p>Background</p> <p><it>Prunus </it>fruit development, growth, ripening, and senescence includes major biochemical and sensory changes in texture, color, and flavor. The genetic dissection of these complex processes has important applications in crop improvement, to facilitate maximizing and maintaining stone fruit quality from production and processing through to marketing and consumption. Here we present an integrated fruit quality gene map of <it>Prunus </it>containing 133 genes putatively involved in the determination of fruit texture, pigmentation, flavor, and chilling injury resistance.</p> <p>Results</p> <p>A genetic linkage map of 211 markers was constructed for an intraspecific peach (<it>Prunus persica</it>) progeny population, Pop-DG, derived from a canning peach cultivar 'Dr. Davis' and a fresh market cultivar 'Georgia Belle'. The Pop-DG map covered 818 cM of the peach genome and included three morphological markers, 11 ripening candidate genes, 13 cold-responsive genes, 21 novel EST-SSRs from the ChillPeach database, 58 previously reported SSRs, 40 RAFs, 23 SRAPs, 14 IMAs, and 28 accessory markers from candidate gene amplification. The Pop-DG map was co-linear with the <it>Prunus </it>reference T × E map, with 39 SSR markers in common to align the maps. A further 158 markers were bin-mapped to the reference map: 59 ripening candidate genes, 50 cold-responsive genes, and 50 novel EST-SSRs from ChillPeach, with deduced locations in Pop-DG via comparative mapping. Several candidate genes and EST-SSRs co-located with previously reported major trait loci and quantitative trait loci for chilling injury symptoms in Pop-DG.</p> <p>Conclusion</p> <p>The candidate gene approach combined with bin-mapping and availability of a community-recognized reference genetic map provides an efficient means of locating genes of interest in a target genome. We highlight the co-localization of fruit quality candidate genes with previously reported fruit quality QTLs. The fruit quality gene map developed here is a valuable tool for dissecting the genetic architecture of fruit quality traits in <it>Prunus </it>crops.</p

    WHOI Hawaii Ocean Timeseries Station (WHOTS) : WHOTS-10 2013 mooring turnaround cruise report

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    The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries Site (WHOTS), 100 km north of Oahu, Hawaii, is intended to provide long-term, high-quality air-sea fluxes as a part of the NOAA Climate Observation Program. The WHOTS mooring also serves as a coordinated part of the Hawaii Ocean Timeseries (HOT) program, contributing to the goals of observing heat, fresh water and chemical fluxes at a site representative of the oligotrophic North Pacific Ocean. The approach is to maintain a surface mooring outfitted for meteorological and oceanographic measurements at a site near 22.75°N, 158°W by successive mooring turnarounds. These observations will be used to investigate air–sea interaction processes related to climate variability. This report documents recovery of the ninth WHOTS mooring (WHOTS-9) and deployment of the tenth mooring (WHOTS-10). Both moorings used Surlyn foam buoys as the surface element and were outfitted with two Air–Sea Interaction Meteorology (ASIMET) systems. Each ASIMET system measures, records, and transmits via Argos satellite the surface meteorological variables necessary to compute air–sea fluxes of heat, moisture and momentum. The upper 155 m of the moorings were outfitted with oceanographic sensors for the measurement of temperature, conductivity and velocity in a cooperative effort with R. Lukas of the University of Hawaii. A pCO2 system and ancillary sensors were installed on the buoys in cooperation with Chris Sabine at the Pacific Marine Environmental Laboratory. A set of radiometers were installed in cooperation with Sam Laney at WHOI. The WHOTS mooring turnaround was done on the NOAA ship Hi’ialakai by the Upper Ocean Processes Group of the Woods Hole Oceanographic Institution. The cruise took place between 9 and 16 July 2013. Operations began with deployment of the WHOTS-10 mooring on 10 July. This was followed by meteorological intercomparisons and CTDs. Recovery of the WHOTS-9 mooring took place on 14 July. This report describes these cruise operations, as well as some of the in-port operations and pre-cruise buoy preparations.Funding was provided by the National Oceanic and Atmospheric Administration under Grant. No. NA090AR4320129 and the Cooperative Institute for the North Atlantic Region (CINAR
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