23 research outputs found

    Towards Formally Verified Compilation of Tag-Based Policy Enforcement

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    Hardware-assisted reference monitoring is receiving increasing attention as a way to improve the security of existing software. One example is the PIPE architecture extension, which attaches metadata tags to register and memory values and executes tag-based rules at each machine instruction to enforce a software-defined security policy. To use PIPE effectively, engineers should be able to write security policies in terms of source-level concepts like functions, local variables, and structured control operators, which are not visible at machine level. It is the job of the compiler to generate PIPE-aware machine code that enforces these source-level policies. The compiler thus becomes part of the monitored system’s trusted computing base---and hence a prime candidate for verification. To formalize compiler correctness in this setting, we extend the source language semantics with its own form of user-specified tag-based monitoring, and show that the compiler preserves that monitoring behavior. The challenges of compilation include mapping source-level monitoring policies to instruction-level tag rules, preserving fail-stop behaviors, and satisfying the surprisingly complex preconditions for conventional optimizations. In this paper, we describe the design and verification of Tagine, a small prototype compiler that translates a simple tagged WHILE language to a tagged register transfer language and performs simple optimizations. Tagine is based on the RTLgen and Deadcode phases of the CompCert compiler, and hence is written and verified in Coq. This work is a first step toward verification of a full-scale compiler for a realistic tagged source language

    Novel loci associated with usual sleep duration: The CHARGE Consortium Genome-Wide Association Study

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    Usual sleep duration is a heritable trait correlated with psychiatric morbidity, cardiometabolic disease and mortality, although little is known about the genetic variants influencing this trait. A genome-wide association study (GWAS) of usual sleep duration was conducted using 18 population-based cohorts totaling 47 180 individuals of European ancestry. Genome-wide significant association was identified at two loci. The strongest is located on chromosome 2, in an intergenic region 35- to 80-kb upstream from the thyroid-specific transcription factor PAX8 (lowest P=1.1 × 10 -9). This finding was replicated in an African-American sample of 4771 individuals (lowest P=9.3 × 10 -4). The strongest combined association was at rs1823125 (P=1.5 × 10 -10, minor allele frequency 0.26 in the discovery sample, 0.12 in the replication sample), with each copy of the minor allele associated with a sleep duration 3.1 min longer per night. The alleles associated with longer sleep duration were associated in previous GWAS with a more favorable metabolic profile and a lower risk of attention deficit hyperactivity disorder. Understanding the mechanisms underlying these associations may help elucidate biological mechanisms influencing sleep duration and its association with psychiatric, metabolic and cardiovascular disease

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    Observation of WWWWWW Production in pppp Collisions at s\sqrt s =13  TeV with the ATLAS Detector

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    International audienceThis Letter reports the observation of WWWWWW production and a measurement of its cross section using 139 fb1^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWWWWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWWWWW production cross section is measured to be 820±100(stat)±80(syst)820 \pm 100\,\text{(stat)} \pm 80\,\text{(syst)} fb, approximately 2.6 standard deviations from the predicted cross section of 511±18511 \pm 18 fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy

    Observation of WWWWWW Production in pppp Collisions at s\sqrt s =13  TeV with the ATLAS Detector

    No full text
    International audienceThis Letter reports the observation of WWWWWW production and a measurement of its cross section using 139 fb1^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWWWWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWWWWW production cross section is measured to be 820±100(stat)±80(syst)820 \pm 100\,\text{(stat)} \pm 80\,\text{(syst)} fb, approximately 2.6 standard deviations from the predicted cross section of 511±18511 \pm 18 fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy

    Observation of WWWWWW Production in pppp Collisions at s\sqrt s =13  TeV with the ATLAS Detector

    No full text
    International audienceThis Letter reports the observation of WWWWWW production and a measurement of its cross section using 139 fb1^{-1} of proton-proton collision data recorded at a center-of-mass energy of 13 TeV by the ATLAS detector at the Large Hadron Collider. Events with two same-sign leptons (electrons or muons) and at least two jets, as well as events with three charged leptons, are selected. A multivariate technique is then used to discriminate between signal and background events. Events from WWWWWW production are observed with a significance of 8.0 standard deviations, where the expectation is 5.4 standard deviations. The inclusive WWWWWW production cross section is measured to be 820±100(stat)±80(syst)820 \pm 100\,\text{(stat)} \pm 80\,\text{(syst)} fb, approximately 2.6 standard deviations from the predicted cross section of 511±18511 \pm 18 fb calculated at next-to-leading-order QCD and leading-order electroweak accuracy
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