5,641 research outputs found

    Compositional Verification for Autonomous Systems with Deep Learning Components

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    As autonomy becomes prevalent in many applications, ranging from recommendation systems to fully autonomous vehicles, there is an increased need to provide safety guarantees for such systems. The problem is difficult, as these are large, complex systems which operate in uncertain environments, requiring data-driven machine-learning components. However, learning techniques such as Deep Neural Networks, widely used today, are inherently unpredictable and lack the theoretical foundations to provide strong assurance guarantees. We present a compositional approach for the scalable, formal verification of autonomous systems that contain Deep Neural Network components. The approach uses assume-guarantee reasoning whereby {\em contracts}, encoding the input-output behavior of individual components, allow the designer to model and incorporate the behavior of the learning-enabled components working side-by-side with the other components. We illustrate the approach on an example taken from the autonomous vehicles domain

    LANDSAT range resource information system project, volume 1

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    There are no author-identified significant results in this report

    The Role of Sirtuin Inhibitors on the Proteomic Responses of the Mussels Mytilus galloprovincialis and Mytilus trossulus to Menadione Induced Oxidative Stress

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    Global climate change imposes physiological constraints on marine ecosystems that can alter the distribution of intertidal organisms. In one such instance, the native cold-adapted mussel Mytilus trossulus is being replaced along its southern range by the invasive warm-adapted Mytilus galloprovincialis. These blue mussels occur throughout rocky intertidal zones where they are subjected to greatly varying environmental conditions known to induce oxidative stress. We hypothesize that while under acute stress, related Mytilus congeners undergo a shift in redox potential from NADH-fueled respiratory pathways to pathways producing NADPH as a way to decrease the production of reactive oxygen species (ROS) and provide reducing equivalents to detoxify ROS. Additionally, we hypothesize that sirtuins (SIRT; a family of NAD-dependent deacetylases) might be involved in the regulation of this metabolic transition. To test the latter, a discovery approach will be used to analyze the proteomic response of M. galloprovincialis and M. trossulus to the pro-oxidant menadione, and sirtuin-inhibitors nicotinamide and suramin. Menadione can induce oxidative stress by increasing endogenous peroxide and superoxide radicals, while suramin and nicotinamde both inhibit sirtuin activity. Organisms were exposed to these compounds in filtered seawater for 8 h, followed by a 24.5 h recovery period under constant aeration. A multivariate analysis utilizing 2D-gel electrophoresis and protein identification via mass spectrometry showed that 18% and 17% of all identified protein spots detected demonstrated changes in abundance in M. galloprovincialis and M. trossulus, respectively. Using matrix-assisted laser desorption ionization (MALDI) tandem time-of-light mass spectrometry, we were able to identify 32-41% of proteins, depending on the species. The two Mytilus congeners showed the greatest differences in changes of protein abundance for oxidative stress proteins (including NADP-dependent isocitrate dehydrogenase). Both congeners showed similar effects in response to simultaneous sirtuin inhibition and MIOS for proteins involved in protein degradation (proteasome), cytoskeletal modifications (actin and tubulin), proteins regulating actin filament growth (F-actin capping protein), amino acid metabolism and stress signaling (G-proteins, small G-proteins and MAPK). Results indicate that protein acetylation plays an important role in the oxidative stress response of M. galloprovincialis. More specifically this suggests that sirtuins play an important role in regulating the general stress response in M. galloprovincialis and thus contribute to the greater stress resistance of this species. Furthermore, changes in the abundance of several molecular chaperones suggest a greater effect of sirtuins in regulating the cellular response to heat stress, which could in part explain why this species is more heat-tolerant than the native M. trossulus

    On Borrowed Time: A Biographical Sketch of Julian Claudius McPheeters

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    The role of metaphor in shaping the identity and agenda of the United Nations: the imagining of an international community and international threat

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    This article examines the representation of the United Nations in speeches delivered by its Secretary General. It focuses on the role of metaphor in constructing a common ‘imagining’ of international diplomacy and legitimising an international organisational identity. The SG legitimises the organisation, in part, through the delegitimisation of agents/actions/events constructed as threatening to the international community and to the well-being of mankind. It is a desire to combat the forces of menace or evil which are argued to motivate and determine the organisational agenda. This is predicated upon an international ideology of humanity in which difference is silenced and ‘working towards the common good’ is emphasised. This is exploited to rouse emotions and legitimise institutional power. Polarisation and antithesis are achieved through the employment of metaphors designed to enhance positive and negative evaluations. The article further points to the constitutive, persuasive and edifying power of topic and situationally-motivated metaphors in speech-making

    Space capsule Patent

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    Manned space capsule configuration for orbital flight and atmospheric reentr

    NASA/American Society for Engineering Education (ASEE) Summer Faculty Fellowship Program, 1985

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    The 1985 NASA/ASEE Summer Faculty Fellowship Research Program was conducted by Texas A&M University and the Johnson Space Center. The ten week program was operated under the auspices of the American Society for Engineering Education (ASEE). The faculty fellows spent the time at JSC engaged in research projects commensurate with their interests and background and worked in collaboration with NASA/JSC colleagues. This document is a compilation of the final reports of their research during the summer of 1985

    TurKit: Tools for iterative tasks on mechanical Turk

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    Mechanical Turk (MTurk) is an increasingly popular web service for paying people small rewards to do human computation tasks. Current uses of MTurk typically post independent parallel tasks. We are exploring an alternative iterative paradigm, in which workers build on or evaluate each other's work. We describe TurKit, a new toolkit for deploying iterative tasks to MTurk, with a familiar imperative programming paradigm that effectively uses MTurk workers as subroutines.National Science Foundation (U.S.). (Grant number IIS-0447800)Quanta Computer (Firm)Massachusetts Institute of Technology. Center for Collective Intelligenc

    Effect of cushion geometry and configuration on the embodied energy of ETFE foil construction

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    The low weight and high spanning capacity of ETFE foil when compared to other translucent cladding materials has potential to reduce the weight of supporting structures and energy embodied in their construction. This paper compares the embodied energy in ETFE cushion panels of different shape, size and configuration, relates these to some built examples. The results are compared with the estimated embodied energy of some built examples of ETFE roofs and from other studies. Factors that influence these are reviewed

    Effects of Differences in Lipid A Structure on TLR4 Pro-Inflammatory Signaling and Inflammasome Activation

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    The vertebrate immune system exists in equilibrium with the microbial world. The innate immune system recognizes pathogen-associated molecular patterns via a family of Toll-like receptors (TLR) that activate cells upon detection of potential pathogens. Because some microbes benefit their hosts, mobilizing the appropriate response, and then controlling that response is critical in the maintenance of health. TLR4 recognizes the various forms of lipid A produced by Gram-negative bacteria. Depending on the structural form of the eliciting lipid A molecule, TLR4 responses range from a highly inflammatory endotoxic response involving inflammasome and other pro-inflammatory mediators, to an inhibitory, protective response. Mounting the correct response against an offending microbe is key to maintaining health when exposed to various bacterial species. Further study of lipid A variants may pave the way to understanding how TLR4 responses are generally able to avoid chronic inflammatory damage
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