1,987 research outputs found

    Practical Hidden Voice Attacks against Speech and Speaker Recognition Systems

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    Voice Processing Systems (VPSes), now widely deployed, have been made significantly more accurate through the application of recent advances in machine learning. However, adversarial machine learning has similarly advanced and has been used to demonstrate that VPSes are vulnerable to the injection of hidden commands - audio obscured by noise that is correctly recognized by a VPS but not by human beings. Such attacks, though, are often highly dependent on white-box knowledge of a specific machine learning model and limited to specific microphones and speakers, making their use across different acoustic hardware platforms (and thus their practicality) limited. In this paper, we break these dependencies and make hidden command attacks more practical through model-agnostic (blackbox) attacks, which exploit knowledge of the signal processing algorithms commonly used by VPSes to generate the data fed into machine learning systems. Specifically, we exploit the fact that multiple source audio samples have similar feature vectors when transformed by acoustic feature extraction algorithms (e.g., FFTs). We develop four classes of perturbations that create unintelligible audio and test them against 12 machine learning models, including 7 proprietary models (e.g., Google Speech API, Bing Speech API, IBM Speech API, Azure Speaker API, etc), and demonstrate successful attacks against all targets. Moreover, we successfully use our maliciously generated audio samples in multiple hardware configurations, demonstrating effectiveness across both models and real systems. In so doing, we demonstrate that domain-specific knowledge of audio signal processing represents a practical means of generating successful hidden voice command attacks

    TRICHOTOMOUS CHOICE: A POSSIBLE SOLUTION TO DUAL RESPONSE OBJECTIVES IN DICHOTOMOUS CHOICE CONTINGENT VALUATION QUESTIONS

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    We investigate the possibility that some respondents to a dichotomous choice question vote YES, even though they would not pay the posted dollar amount in order to register support for the project or policy. A trichotomous choice question format is proposed to determine if allowing respondents the opportunity to vote in favor of a project at an amount less than their bid affects estimated willingness to pay. Using univariate and multivariate tests, we find the trichotomous choice question format reduces the number of YES responses and produces a statistically significant decrease in willingness to pay for an open-space program.Research Methods/ Statistical Methods,

    The role of HER1-HER4 and EGFRvIII in hormone-refractory prostate cancer

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    <b>Purpose</b>: The role of the type I receptor tyrosine kinase (HER) family in progression of prostate cancer is controversial. Breast cancer studies show that these receptors should be investigated as a family. The current study investigates expression of HER1-HER4 and EGFRvIII in matched hormone-sensitive and hormone-refractory prostate tumors. <b>Experimental Design</b>: Immunohistochemical analysis was used to investigate protein expression of HER1-HER4, EGFRvIII, and phosphorylated Akt (pAkt) in matched hormone-sensitive and hormone-refractory prostate tumors. <b>Results</b>: Surprisingly, high HER2 membrane expression in hormone-sensitive tumors was associated with an increased time to biochemical relapse (<i>P</i> = 0.0003), and this translated into longer overall survival (<i>P</i> = 0.0021). Consistent with other studies, HER4 membrane expression in hormone-sensitive tumors was associated with longer time to biochemical relapse (<i>P</i> = 0.042), and EGFRvIII membrane expression was associated with shorter time to biochemical relapse (<i>P</i> = 0.015). An increase in pAkt expression was associated with reduced survival (<i>P</i> = 0.0098). Multivariate analysis showed that HER2 was an independent positive predictive marker of time to relapse in hormone-sensitive prostate tumors (<i>P</i> = 0.014). In contrast, high HER2 expression in hormone-refractory tumors was associated with decreased time to death from biochemical relapse (<i>P</i> = 0.039), and EGFRvIII nuclear expression was associated with decreased time to death from biochemical relapse and decreased overall survival (<i>P</i> = 0.02 and <i>P</i> = 0.005). <b>Conclusion</b>: These results suggest that the HER family may have multiple roles in prostate cancer, and that expression of the proteins alone is insufficient to predict the biological response that they may elicit

    Continued monitoring of acute kidney injury survivors might not be necessary in those regaining an estimated glomerular filtration rate > 60 mL/min at 1 year

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    Background. Severe acute kidney injury (AKI) among hospitalized patients often necessitates initiation of short-term dialysis. Little is known about the long-term outcome of those who recover to normal renal function. The aim of this study was to determine the long-term renal outcome of patients experiencing AKI requiring dialysis secondary to hypoperfusion injury and/or sepsis who recovered to apparently normal renal function. Methods. All adult patients with AKI requiring dialysis in our centre between 1 January 1980 and 31 December 2010 were identified. We included patients who had estimated glomerular filtration rate (eGFR) >60 mL/min/1.73 m2 12 months or later after the episode of AKI. Patients were followed up until 3 March 2015. The primary outcome was time to chronic kidney disease (CKD) (defined as eGFR persistently <60 mL/min/1.73 m2) from first dialysis for AKI. Results. Among 2922 patients with a single episode of dialysis-requiring AKI, 396 patients met the study inclusion criteria. The mean age was 49.8 (standard deviation 16.5) years and median follow-up was 7.9 [interquartile range (IQR) 4.8–12.7] years. Thirty-five (8.8%) of the patients ultimately developed CKD after a median of 5.3 (IQR 2.8–8.0) years from first dialysis for AKI giving an incidence rate of 1 per 100 person-years. Increasing age, diabetes and vascular disease were associated with higher risk of progression to CKD [adjusted hazard ratios (95% confidence interval): 1.06 (1.03, 1.09), 3.05 (1.41, 6.57) and 3.56 (1.80, 7.03), respectively]. Conclusions. Recovery from AKI necessitating in-hospital dialysis was associated with a very low risk of progression to CKD. Most of the patients who progressed to CKD had concurrent medical conditions meriting monitoring of renal function. Therefore, it seems unlikely that regular follow-up of renal function is beneficial in patients who recover to eGFR >60 mL/min/1.73 m2 by 12 months after an episode of AKI

    Renal replacement modality and stroke risk in end-stage renal disease—a national registry study

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    Background: The risk of stroke in end-stage renal disease (ESRD) on renal replacement therapy (RRT) is up to 10-fold greater than the general population. However, whether this increased risk differs by RRT modality is unclear. Methods: We used data contained in the Scottish Renal Registry and the Scottish Stroke Care Audit to identify stroke in all adult patients who commenced RRT for ESRD from 2005 to 2013. Incidence rate was calculated and regression analyses were performed to identify variables associated with stroke. We explored the effect of RRT modality at initiation and cumulative dialysis exposure by time-dependent regression analysis, using transplant recipients as the reference group. Results: A total of 4957 patients commenced RRT for ESRD. Median age was 64.5 years, 41.5% were female and 277 patients suffered a stroke (incidence rate was 18.6/1000 patient-years). Patients who had stroke were older, had higher blood pressure and were more likely to be female and have diabetes. On multivariable regression older age, female sex, diabetes and higher serum phosphate were associated with risk of stroke. RRT modality at initiation was not. On time-dependent analysis, haemodialysis (HD) exposure was independently associated with increased risk of stroke. Conclusions: In patients with ESRD who initiate RRT, HD use independently increases risk of stroke compared with transplantation. Use of peritoneal dialysis did not increase risk on adjusted analysis

    End stage renal disease and survival in people with diabetes:a national database linkage study

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    © The Author 2014. Published by Oxford University Press on behalf of the Association of Physicians. Funding This work was supported by the Wellcome Trust through the Scottish Health Informatics Programme (SHIP). The SHIP is collaboration between the Universities of Aberdeen, Dundee, Edinburgh, Glasgow and St Andrews and the Information Services Division of National Health Service National Service Scotland. Funding for diabetes register linkage and data extraction was provided by the Chief Scientist’s Office of the Scottish Government. The Scottish Diabetes Research Network receives financial support from National Health Services Research Scotland. The Scottish Renal Registry is funded by the Information Services Division of National Health Service National Services Scotland but relies heavily on the goodwill of the contributing renal units who spent a large amount time working with Scottish Renal Registry staff to ensure that the data held within the register are accurate and complete.Peer reviewedPublisher PD

    The Minimal Length of a Lagrangian Cobordism between Legendrians

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    To investigate the rigidity and flexibility of Lagrangian cobordisms between Legendrian submanifolds, we investigate the minimal length of such a cobordism, which is a 11-dimensional measurement of the non-cylindrical portion of the cobordism. Our primary tool is a set of real-valued capacities for a Legendrian submanifold, which are derived from a filtered version of Legendrian Contact Homology. Relationships between capacities of Legendrians at the ends of a Lagrangian cobordism yield lower bounds on the length of the cobordism. We apply the capacities to Lagrangian cobordisms realizing vertical dilations (which may be arbitrarily short) and contractions (whose lengths are bounded below). We also study the interaction between length and the linking of multiple cobordisms as well as the lengths of cobordisms derived from non-trivial loops of Legendrian isotopies.Comment: 33 pages, 9 figures. v2: Minor corrections in response to referee comments. More general statement in Proposition 3.3 and some reorganization at the end of Section

    Spin polarization and magneto-luminescence of confined electron-hole systems

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    A BCS-like variational wave-function, which is exact in the infinite field limit, is used to study the interplay among Zeeman energies, lateral confinement and particle correlations induced by the Coulomb interactions in strongly pumped neutral quantum dots. Band mixing effects are partially incorporated by means of field-dependent masses and g-factors. The spin polarization and the magneto-luminescence are computed as functions of the number of electron-hole pairs present in the dot and the applied magnetic field.Comment: To appear in Phys. Rev.

    Correlated sampling in quantum Monte Carlo: a route to forces

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    In order to find the equilibrium geometries of molecules and solids and to perform ab initio molecular dynamics, it is necessary to calculate the forces on the nuclei. We present a correlated sampling method to efficiently calculate numerical forces and potential energy surfaces in diffusion Monte Carlo. It employs a novel coordinate transformation, earlier used in variational Monte Carlo, to greatly reduce the statistical error. Results are presented for first-row diatomic molecules.Comment: 5 pages, 2 postscript figure

    Collection and determinants of patient reported outcome measures in haemodialysis patients in Scotland

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    Background: Patient reported outcome measures (PROMs) can evaluate the quality of health in patients with established renal failure. There is limited experience of their use within national renal registries.Aim: To describe the Scottish Renal Registry’s (SRR) experience of collecting PROMS in the haemodialysis population and correlate PROMS to demographic and clinical parameters.Design: Retrospective observational cross-sectional study.Methods: Haemodialysis patients in Scotland were invited to complete the KDQOL™-36 questionnaire on the day of the annual SRR census in 2015 and 2016. Questionnaires were linked to census demographic and clinical variables.Results: In 2016 738 questionnaires were linked to census data (39% of prevalent haemodialysis population). Response rates differed with age (≥ 65 years 42%, < 65 years 36%) [χ2 p=0.006]; duration of renal replacement therapy (<1 year 46%, ≥1 < 5 years 38%, ≥ 5 years 33%) [χ2 p=0.002] and social class (Scottish Index of Multiple Deprivation (SIMD) Class 1 32%, Class 2 41%, Class 3 40%, Class 4 48%, Class 5 40%) [χ2 p<0.001]. There were significant differences in PROMs with age, SIMD quintile and primary renal diagnosis. Achieving a urea reduction ratio of >65% and dialysing through arteriovenous access were associated with significantly higher PROMs. PROMs were not affected by haemoglobin or phosphate concentration.Conclusions: Routine collection of PROMs is feasible and can identify potentially under-recognised and treatable determinants to quality of life. The association between attaining recommended standards of care and improved PROMs is striking. Individual and population-wide strategies are required to improve PROMs
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