1,321 research outputs found
Defend Data Poisoning Attacks on Voice Authentication
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
We give faster algorithms and improved sample complexities for estimating the
top eigenvector of a matrix -- i.e. computing a unit vector such
that :
Offline Eigenvector Estimation: Given an explicit with , we show how to compute an approximate top
eigenvector in time and . Here is the number of nonzeros in ,
is the stable rank, is the relative eigengap. By separating the
dependence from the 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 and . Our second running
time improves these further when .
Online Eigenvector Estimation: Given a distribution with covariance
matrix and a vector which is an approximate top
eigenvector for , we show how to refine to an approximation
using samples from . Here is a
natural notion of variance. Combining our algorithm with previous work to
initialize , we obtain improved sample complexity and runtime results
under a variety of assumptions on .
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
Arguably, the simplest chiral gauge theories are with
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 , while the global symmetry is broken to
for moderately large .Comment: 7 pages,3 figure
NH Beverage Alcohol Summit
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
The long-root elements in Lie algebras of Chevalley type have been well
studied and can be characterized as extremal elements, that is, elements
such that the image of (\ad x)^2 lies in the subspace spanned by . 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 the graph is a path of length ,
and for the graph is the triangle connected to a path of length .Comment: 26 pages, 6 figure
Establishing disability weights for congenital pediatric surgical conditions: A multi-modal approach
__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
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
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
<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
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
- …