3,320 research outputs found

    Effective Universal Unrestricted Adversarial Attacks using a MOE Approach

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    Recent studies have shown that Deep Leaning models are susceptible to adversarial examples, which are data, in general images, intentionally modified to fool a machine learning classifier. In this paper, we present a multi-objective nested evolutionary algorithm to generate universal unrestricted adversarial examples in a black-box scenario. The unrestricted attacks are performed through the application of well-known image filters that are available in several image processing libraries, modern cameras, and mobile applications. The multi-objective optimization takes into account not only the attack success rate but also the detection rate. Experimental results showed that this approach is able to create a sequence of filters capable of generating very effective and undetectable attacks

    Non-thermal leptogenesis with strongly hierarchical right handed neutrinos

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    Assuming the Dirac-type neutrino masses m_D are related to quark or charged lepton masses, neutrino oscillation data indicate that right handed neutrino masses are in general strongly hierarchical. In particular, if m_D is similar to the up-type quark masses, the mass of the lightest right handed neutrino M_1<~10^6 GeV. We show that non-thermal leptogenesis by inflaton decay can yield sufficient baryon asymmetry despite this constraint, and discuss how the asymmetry is correlated with the low energy neutrino masses and CP-violating phases.Comment: 7 pages, 5 figures. v2: added some comments and references, v3: minor corrections and additions, v4: a typo corrected, published versio

    Hiding relativistic degrees of freedom in the early universe

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    We quantify the extent to which extra relativistic energy density can be concealed by a neutrino asymmetry without conflicting with the baryon asymmetry measured by the Wilkinson Microwave Anisotropy Probe (WMAP). In the presence of a large electron neutrino asymmetry, slightly more than seven effective neutrinos are allowed by Big Bang Nucleosynthesis (BBN) and WMAP at 2\sigma. The same electron neutrino degeneracy that reconciles the BBN prediction for the primordial helium abundance with the observationally inferred value also reconciles the LSND neutrino with BBN by suppressing its thermalization prior to BBN.Comment: 5 pages, 5 figure

    Machine learning and domain adaptation to monitor yoghurt fermentation using ultrasonic measurements

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    In manufacturing environments, real-time monitoring of yoghurt fermentation is required to maintain an optimal production schedule, ensure product quality, and prevent the growth of pathogenic bacteria. Ultrasonic sensors combined with machine learning models offer the potential for non-invasive process monitoring. However, methods are required to ensure the models are robust to changing ultrasonic measurement distributions as a result of changing process conditions. As it is unknown when these changes in distribution will occur, domain adaptation methods are needed that can be applied to newly acquired data in real-time. In this work, yoghurt fermentation processes are monitored using non-invasive ultrasonic sensors. Furthermore, a transmission based method is compared to an industrially-relevant non-transmission method which does not require the sound wave to travel through the fermenting yoghurt. Three machine learning algorithms were investigated including fully-connected neural networks, fully-connected neural networks with long short-term memory layers, and convolutional neural networks with long short-term memory layers. Three real-time domain adaptation strategies were also evaluated, namely; feature alignment, prediction alignment, and feature removal. The most accurate method (mean squared error of 0.008 to predict pH during fermentation) was non-transmission based and used convolutional neural networks with long short-term memory layers, and a combination of all three domain adaption methods

    The effect of monovalent (Na+, K+) and divalent (Ca2+, Mg2+) cations on rapeseed oleosome (oil body) extraction and stability at pH 7

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    Oleosomes are storage vehicles of TAGs in plant seeds. They are protected with a phospholipid-protein monolayer and extracted with alkaline aqueous media; however, pH adjustment intensifies the extraction process. Therefore the aim of this work was to investigate the extraction mechanism of rapeseed oleosomes at pH 7 and at the presence of monovalent and divalent cations (Na+, K+, Mg2+, and Ca+2). The oleosome yield at pH 9.5 was 64 wt%, while the yield at pH 7 with H2O was just 43 wt%. The presence of cations at pH 7, significantly enhanced the yield, with K+ giving the highest yield (64 wt%). The cations affected the oleosome interface and their interactions. The presence of monovalent cations resulted in aggregation and minor coalescence, while divalent cations resulted in extensive coalescence. These results help to understand the interactions of oleosomes in their native matrix and design simple extraction processes at neutral conditions

    Update on neutrino mixing in the early Universe

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    From the current cosmological observations of CMB and nuclear abundances we show, with an analytic procedure, that the total effective number of extra neutrino species ΔNÎœtot<0.3\Delta N_{\nu}^{\rm tot}< 0.3. We also describe the possible signatures of non standard effects that could be revealed in future CMB observations. This cosmological information is then applied to neutrino mixing models. Taking into account the recent results from the SNO and SuperKamiokande experiments, disfavouring pure active to sterile neutrino oscillations, we show that all 4 neutrino mixing models, both of 2+2 and 3+1 type, lead to a full thermalization of the sterile neutrino flavor. Moreover such a sterile neutrino production excludes the possibility of an electron neutrino asymmetry generation and we conclude that ΔNÎœtot≃1\Delta N_{\nu}^{\rm tot}\simeq 1, in disagreement with the cosmological bound. This result is valid under the assumption that the initial neutrino asymmetries are small. We suggest the existence of a second sterile neutrino flavor, with mixing properties such to generate a large electron neutrino asymmetry, as a possible way out.Comment: 29 pages, 3 figures; to appear on Phys.Rev.D; added discussion (at page 19) and references; typos correcte
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