19,588 research outputs found

    Using Taint Analysis and Reinforcement Learning (TARL) to Repair Autonomous Robot Software

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    It is important to be able to establish formal performance bounds for autonomous systems. However, formal verification techniques require a model of the environment in which the system operates; a challenge for autonomous systems, especially those expected to operate over longer timescales. This paper describes work in progress to automate the monitor and repair of ROS-based autonomous robot software written for an a-priori partially known and possibly incorrect environment model. A taint analysis method is used to automatically extract the data-flow sequence from input topic to publish topic, and instrument that code. A unique reinforcement learning approximation of MDP utility is calculated, an empirical and non-invasive characterization of the inherent objectives of the software designers. By comparing off-line (a-priori) utility with on-line (deployed system) utility, we show, using a small but real ROS example, that it's possible to monitor a performance criterion and relate violations of the criterion to parts of the software. The software is then patched using automated software repair techniques and evaluated against the original off-line utility.Comment: IEEE Workshop on Assured IEEE Workshop on Assured Autonomous Systems, May, 202

    High-Precision Entropy Values for Spanning Trees in Lattices

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    Shrock and Wu have given numerical values for the exponential growth rate of the number of spanning trees in Euclidean lattices. We give a new technique for numerical evaluation that gives much more precise values, together with rigorous bounds on the accuracy. In particular, the new values resolve one of their questions.Comment: 7 pages. Revision mentions alternative approach. Title changed slightly. 2nd revision corrects first displayed equatio

    Standard Model Top Quark Asymmetry at the Fermilab Tevatron

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    Top quark pair production at proton-antiproton colliders is known to exhibit a forward-backward asymmetry due to higher-order QCD effects. We explore how this asymmetry might be studied at the Fermilab Tevatron, including how the asymmetry depends on the kinematics of extra hard partons. We consider results for top quark pair events with one and two additional hard jets. We further note that a similar asymmetry, correlated with the presence of jets, arises in specific models for parton showers in Monte Carlo simulations. We conclude that the measurement of this asymmetry at the Tevatron will be challenging, but important both for our understanding of QCD and for our efforts to model it.Comment: 26 p., 10 embedded figs., comment added, version to appear in PR

    A 233 km Tunnel for Lepton and Hadron Colliders

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    A decade ago, a cost analysis was conducted to bore a 233 km circumference Very Large Hadron Collider (VLHC) tunnel passing through Fermilab. Here we outline implementations of e+e−e^+e^-, ppˉp \bar{p}, and μ+μ−\mu^+ \mu^- collider rings in this tunnel using recent technological innovations. The 240 and 500 GeV e+e−e^+e^- colliders employ Crab Waist Crossings, ultra low emittance damped bunches, short vertical IP focal lengths, superconducting RF, and low coercivity, grain oriented silicon steel/concrete dipoles. Some details are also provided for a high luminosity 240 GeV e+e−e^+ e^- collider and 1.75 TeV muon accelerator in a Fermilab site filler tunnel. The 40 TeV ppˉp \bar{p} collider uses the high intensity Fermilab pˉ\bar{p} source, exploits high cross sections for ppˉp \bar{p} production of high mass states, and uses 2 Tesla ultra low carbon steel/YBCO superconducting magnets run with liquid neon. The 35 TeV muon ring ramps the 2 Tesla superconducting magnets at 9 Hz every 0.4 seconds, uses 250 GV of superconducting RF to accelerate muons from 1.75 to 17.5 TeV in 63 orbits with 71% survival, and mitigates neutrino radiation with phase shifting, roller coaster motion in a FODO lattice.Comment: LaTex, 6 pages, 1 figure, Advanced Accelerator Concepts Workshop, Austin, TX, 10-15 June 201

    Towards high quality text entry on smartwatches

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    Smartwatches now provide users with access to many applications on smartphones direct from their wrists, without the need to touch their smartphone. While applications such as email, messaging, calendar and social networking provide views on the watch, there is normally no text entry method so users cannot reply on the same device. Here we introduce requirements for smartwatch text entry, an optimised alphabetic layout and present a prototype implementation together with preliminary user feedback. While raising some problems, the feedback gives indicates that reasonable quality and speed is achievable on a smartwatch and encourages our future work

    Flows driven by Banach space-valued rough paths

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    We show in this note how the machinery of C^1-approximate flows devised in the work "Flows driven by rough paths", and applied there to reprove and extend most of the results on Banach space-valued rough differential equations driven by a finite dimensional rough path, can be used to deal with rough differential equations driven by an infinite dimensional Banach space-valued weak geometric Holder p-rough paths, for any p>2, giving back Lyons' theory in its full force in a simple way.Comment: 8 page

    Localization Transition of Biased Random Walks on Random Networks

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    We study random walks on large random graphs that are biased towards a randomly chosen but fixed target node. We show that a critical bias strength b_c exists such that most walks find the target within a finite time when b>b_c. For b<b_c, a finite fraction of walks drifts off to infinity before hitting the target. The phase transition at b=b_c is second order, but finite size behavior is complex and does not obey the usual finite size scaling ansatz. By extending rigorous results for biased walks on Galton-Watson trees, we give the exact analytical value for b_c and verify it by large scale simulations.Comment: 4 pages, includes 4 figure

    It takes one to know one: Relationship between lie detection and psychopathy

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    We investigated primary and secondary psychopathy and the ability to detect high-stakes, real-life emotional lies in an on-line experiment (N = 150). Using signal detection analysis, we found that lie detection ability was overall above chance level, there was a tendency towards responding liberally to the test stimuli, and women were more accurate than men Further, sex moderated the relationship between psychopathy and lie detection ability; in men, primary psychopathy had a significant positive correlation with the ability to detect lies, whereas in women there was a significant negative correlation with deception detection. The results are discussed with reference to evolutionary theory and sex differences in processing socio-emotional information
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