13,530 research outputs found

    PerfWeb: How to Violate Web Privacy with Hardware Performance Events

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    The browser history reveals highly sensitive information about users, such as financial status, health conditions, or political views. Private browsing modes and anonymity networks are consequently important tools to preserve the privacy not only of regular users but in particular of whistleblowers and dissidents. Yet, in this work we show how a malicious application can infer opened websites from Google Chrome in Incognito mode and from Tor Browser by exploiting hardware performance events (HPEs). In particular, we analyze the browsers' microarchitectural footprint with the help of advanced Machine Learning techniques: k-th Nearest Neighbors, Decision Trees, Support Vector Machines, and in contrast to previous literature also Convolutional Neural Networks. We profile 40 different websites, 30 of the top Alexa sites and 10 whistleblowing portals, on two machines featuring an Intel and an ARM processor. By monitoring retired instructions, cache accesses, and bus cycles for at most 5 seconds, we manage to classify the selected websites with a success rate of up to 86.3%. The results show that hardware performance events can clearly undermine the privacy of web users. We therefore propose mitigation strategies that impede our attacks and still allow legitimate use of HPEs

    The RUTH Gripper: systematic object-invariant prehensile in-hand manipulation via reconfigurable underactuation

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    We introduce a reconfigurable underactuated robothand able to perform systematic prehensile in-hand manipu-lations regardless of object size or shape. The hand utilisesa two-degree-of-freedom five-bar linkage as the palm of thegripper, with three three-phalanx underactuated fingers—jointlycontrolled by a single actuator—connected to the mobile revolutejoints of the palm. Three actuators are used in the robot handsystem, one for controlling the force exerted on objects by thefingers and two for changing the configuration of the palm.This novel layout allows decoupling grasping and manipulation,facilitating the planning and execution of in-hand manipulationoperations. The reconfigurable palm provides the hand withlarge grasping versatility, and allows easy computation of amap between task space and joint space for manipulation basedon distance-based linkage kinematics. The motion of objects ofdifferent sizes and shapes from one pose to another is thenstraightforward and systematic, provided the objects are keptgrasped. This is guaranteed independently and passively by theunderactuated fingers using a custom tendon routing method,which allows no tendon length variation when the relative fingerbase position changes with palm reconfigurations. We analysethe theoretical grasping workspace and manipulation capabilityof the hand, present algorithms for computing the manipulationmap and in-hand manipulation planning, and evaluate all theseexperimentally. Numerical and empirical results of several ma-nipulation trajectories with objects of different size and shapeclearly demonstrate the viability of the proposed concept

    Ceratocystis fimbriata alters root system architecture and causes symptom development only in detached storage roots in Bayou Belle and Beauregard sweet potato

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    Little is known about how the sweet potato (Ipomoea batatas) root system responds to Ceratocystis fimbriata in the growth substrate. Understanding whether the fungus affects the root system before harvest of storage roots (SR) could guide timing of management efforts. Cuttings of cultivars Bayou Belle and Beauregard, both previously considered susceptible to black rot, were in unamended or infested sand. At the onset of SR formation, effects on first- and second-order lateral root (LR) length and number among and within treatments, cultivars and replicate experiments were recorded. First-order LR length in inoculated Bayou Belle plants was 31% greater than in inoculated plants of cultivar Beauregard in Expt 1, but there were no differences in Expt 2. Second-order LR length varied among, and within, cultivars, inoculum treatments and experiments in Expts 1 and 2. At 49 days after planting in Expt 1, only inoculated plants had necrotic lesions on stems in both cultivars, with more than twice as many recorded on Bayou Belle than Beauregard. SR had no lesions at harvest. Detached SR originating from inoculated treatments and stored in sampling bags for 25 days developed black rot lesions at either end of the SR (45% and 31% of total in Expt 1 and Expt 2, respectively) or elsewhere, including those centred on LR emergence sites or lenticels (55% and 69%, respectively). Exposing developing plants to inoculation may reveal differences in SR susceptibility not found when harvested SR are wounded and inoculated

    Coupling of effective one-dimensional two-level atoms to squeezed light

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    A cavity QED system is analyzed which duplicates the dynamics of a two-level atom in free space interacting exclusively with broadband squeezed light. We consider atoms in a three or four-level Lambda-configuration coupled to a high-finesse optical cavity which is driven by a squeezed light field. Raman transitions are induced between a pair of stable atomic ground states via the squeezed cavity mode and coherent driving fields. An analysis of the reduced master equation for the atomic ground states shows that a three-level atomic system has insufficient parameter flexibility to act as an effective two-level atom interacting exclusively with a squeezed reservoir. However, the inclusion of a fourth atomic level, coupled dispersively to one of the two ground states by an auxiliary laser field, introduces an extra degree of freedom and enables the desired interaction to be realised. As a means of detecting the reduced quadrature decay rate of the effective two-level system, we examine the transmission spectrum of a weak coherent probe field incident upon the cavity

    Strategic Players for Identifying Optimal Social Network Intervention Subjects

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    We present a method whereby social network ties are used to identify behavioral leaders who are situated in the network such that these individuals are: 1) able to influence other individuals who are in need of and most receptive to intervention, thereby optimizing the impact of the intervention; and 2) not embedded with ties to individuals that are likely to be behaviorally antagonistic to the intervention or that would compromise the optimal impact of intervention. In this study we developed a method that we call Strategic Players, which is a solution for identifying a set of players who are close to a target subset of the network (i.e., the target group), and far away from the subset we wish to avoid (i.e. the avoid group), where the proximity to either the target or avoid group may be facilitated by network members who are in neither group (i.e. the neutral group). This solution seeks to maximize the diffusion of the behavior to the target group while minimizing contact and influence to the avoid group. We apply this method to two different social networks, and one simulated social network

    Shed urinary ALCAM is an independent prognostic biomarker of three-year overall survival after cystectomy in patients with bladder cancer.

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    Proteins involved in tumor cell migration can potentially serve as markers of invasive disease. Activated Leukocyte Cell Adhesion Molecule (ALCAM) promotes adhesion, while shedding of its extracellular domain is associated with migration. We hypothesized that shed ALCAM in biofluids could be predictive of progressive disease. ALCAM expression in tumor (n = 198) and shedding in biofluids (n = 120) were measured in two separate VUMC bladder cancer cystectomy cohorts by immunofluorescence and enzyme-linked immunosorbent assay, respectively. The primary outcome measure was accuracy of predicting 3-year overall survival (OS) with shed ALCAM compared to standard clinical indicators alone, assessed by multivariable Cox regression and concordance-indices. Validation was performed by internal bootstrap, a cohort from a second institution (n = 64), and treatment of missing data with multiple-imputation. While ALCAM mRNA expression was unchanged, histological detection of ALCAM decreased with increasing stage (P = 0.004). Importantly, urine ALCAM was elevated 17.0-fold (P < 0.0001) above non-cancer controls, correlated positively with tumor stage (P = 0.018), was an independent predictor of OS after adjusting for age, tumor stage, lymph-node status, and hematuria (HR, 1.46; 95% CI, 1.03-2.06; P = 0.002), and improved prediction of OS by 3.3% (concordance-index, 78.5% vs. 75.2%). Urine ALCAM remained an independent predictor of OS after accounting for treatment with Bacillus Calmette-Guerin, carcinoma in situ, lymph-node dissection, lymphovascular invasion, urine creatinine, and adjuvant chemotherapy (HR, 1.10; 95% CI, 1.02-1.19; P = 0.011). In conclusion, shed ALCAM may be a novel prognostic biomarker in bladder cancer, although prospective validation studies are warranted. These findings demonstrate that markers reporting on cell motility can act as prognostic indicators

    Momentum-Dependent Mean Field Based Upon the Dirac-Brueckner Approach for Nuclear Matter

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    A momentum-dependent mean field potential, suitable for application in the transport-model description of nucleus-nucleus collisions, is derived in a microscopic way. The derivation is based upon the Bonn meson-exchange model for the nucleon-nucleon interaction and the Dirac-Brueckner approach for nuclear matter. The properties of the microscopic mean field are examined and compared with phenomenological parametrizations which are commonly used in transport-model calculations.Comment: 15 pages text (RevTex) and 4 figures (postscript in a separate uuencoded file), UI-NTH-930

    Extracting Spatial Information from Noise Measurements of Multi-Spatial-Mode Quantum States

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    We show that it is possible to use the spatial quantum correlations present in twin beams to extract information about the shape of a mask in the path of one of the beams. The scheme, based on noise measurements through homodyne detection, is useful in the regime where the number of photons is low enough that direct detection with a photodiode is difficult but high enough that photon counting is not an option. We find that under some conditions the use of quantum states of light leads to an enhancement of the sensitivity in the estimation of the shape of the mask over what can be achieved with a classical state with equivalent properties (mean photon flux and noise properties). In addition, we show that the level of enhancement that is obtained is a result of the quantum correlations and cannot be explained with only classical correlations

    Spallation-Like Phenomenon Induced By Laser Shock Peening Surface Treatment On 7050 Aluminum Alloy

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    Laser shock peening (LSP) is a promising surface treatment for fatigue life extension of metallic materials. The benefits include deeper residual stresses (>1 mm) and a smoother surface finish than conventional glass bead peening. However, fatigue tests on 7050 aluminium alloy specimens have shown that LSP may cause a reduction in life due to internal cracking generated during the process. A series of tests were carried out to identify any technological risks such as internal cracking associated with the use of LSP. Numerical modelling was also carried out and the results of this numerical prediction agreed well with the experimental results
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