5,736 research outputs found

    Miniaturized haploscope for testing binocular vision

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    Device can reproduce virtually all binocular stimulus conditions (target configuration, vergence angle, and accommodative distance) used to test binocular performance. All subsystems of electronic controls are open-loop and solid-state-controlled and, with the exception of vergence angle drive, utilize dc stepping motors as prime movers. Arrangement is also made for readouts of each variable

    Cost-Effectiveness of Targeted Reemployment Bonuses

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    Targeting reemployment bonus offers to unemployment insurance (UI) claimants identified as most likely to exhaust benefits is estimated to reduce benefit payments. While earlier research indicated that non-targeted reemployment bonus offers would not be good public policy, in this paper we show that targeting bonus offers with profiling models similar to those in state Worker Profiling and Reemployment Services (WPRS) systems can improve their cost effectiveness. Since estimated average benefit payments do not steadily decline as the eligibility screen is gradually tightened, we find that narrow targeting is not optimal. The best candidate to emerge for a targeted reemployment bonus is a low bonus amount with a long qualification period, targeted to the half of profiled claimants most likely to exhaust their UI benefit entitlement.reemployment, bonus, UI, personal, accounts, PRA, unemployment, insurance, Upjohn, Institute, O'Leary, Decker, Wandner

    Effective Governance of Global Financial Markets:An Evolutionary Plan for Reform

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    Runaway electrons, which are generated in a plasma where the induced electric field exceeds a certain critical value, can reach very high energies in the MeV range. For such energetic electrons, radiative losses will contribute significantly to the momentum space dynamics. Under certain conditions, due to radiative momentum losses, a non-monotonic feature - a ‘bump' - can form in the runaway electron tail, creating a potential for bump-on-tail-type instabilities to arise. Here, we study the conditions for the existence of the bump. We derive an analytical threshold condition for bump appearance and give an approximate expression for the minimum energy at which the bump can appear. Numerical calculations are performed to support the analytical derivation

    A mathematical model of a single main rotor helicopter for piloted simulation

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    A mathematical model, suitable for piloted simulation of the flying qualities of helicopters, is a nonlinear, total force and moment model of a single main rotor helicopter. The model has ten degrees of freedom: six rigid body, three rotor flapping, and the rotor rotational degrees of freedom. The rotor model assumes rigid blades with rotor forces and moments radially integrated and summed about the azimuth. The fuselage aerodynamic model uses a detailed representation over a nominal angle of attack and sideslip range of + or - 15 deg., as well as a simplified curve fit at large angles of attack or sideslip. Stabilizing surface aerodynamics are modeled with a lift curve slope between stall limits and a general curve fit for large angles of attack. A generalized stability and control augmentation system is described. Additional computer subroutines provide options for a simplified engine/governor model, atmospheric turbulence, and a linearized six degree of freedom dynamic model for stability and control analysis

    Hadron structure in tau -> KKpi nu_tau decays

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    We analyse the hadronization structure of both vector and axial-vector currents leading to tau -> KKpi nu_tau decays. At leading order in the 1/Nc expansion, and considering only the contribution of the lightest resonances, we work out, within the framework of the resonance chiral Lagrangian, the structure of the local vertices involved in those processes. The couplings in the resonance theory are constrained by imposing the asymptotic behaviour of vector and axial-vector spectral functions ruled by QCD. In this way we predict the hadron spectra and conclude that, contrarily to previous assertions, the vector contribution dominates by far over the axial-vector one in all KKpi charge channels.Comment: 32 pages, 7 figure

    Perturbation analysis of trapped-particle dynamics in axisymmetric dipole geometry

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    The perturbation analysis of the bounce action-angle coordinates (J,ζ)(J,\zeta) for charged particles trapped in an axisymmetric dipole magnetic field is presented. First, the lowest-order bounce action-angle coordinates are derived for deeply-trapped particles in the harmonic-oscillator approximation. Next, the Lie-transform perturbation method is used to derive higher-order anharmonic action-angle corrections. Explicit expressions (with anharmonic corrections) for the canonical parallel coordinates s(J,ζ)s(J,\zeta) and p∄(J,ζ)p_{\|}(J,\zeta) are presented, which satisfy the canonical identity {s,  p∄}(J,ζ)≡1\{s,\; p_{\|}\}(J,\zeta) \equiv 1. Lastly, analytical expressions for the bounce and drift frequencies (which include anharmonic corrections) yield excellent agreement with exact numerical results.Comment: 16 pages, 3 figure

    The Mark 3 Haploscope

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    A computer-operated binocular vision testing device was developed as one part of a system designed for NASA to evaluate the visual function of astronauts during spaceflight. This particular device, called the Mark 3 Haploscope, employs semi-automated psychophysical test procedures to measure visual acuity, stereopsis, phoria, fixation disparity, refractive state and accommodation/convergence relationships. Test procedures are self-administered and can be used repeatedly without subject memorization. The Haploscope was designed as one module of the complete NASA Vision Testing System. However, it is capable of stand-alone operation. Moreover, the compactness and portability of the Haploscope make possible its use in a broad variety of testing environments

    Answers that Have Integrity

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    [EN] Answers to queries in possibly inconsistent databases may not have integrity. We formalize ‘has integrity’ on the basis of a definition of ‘causes’. A cause of an answer is a minimal excerpt of the database that explains why the answer has been given. An answer has integrity if one of its causes does not overlap with any cause of integrity violation.Supported by FEDER and the Spanish grants TIN2009-14460-C03, TIN2010-17139.Decker, H. (2011). Answers that Have Integrity. Lecture Notes in Computer Science. 6834:54-72. https://doi.org/10.1007/978-3-642-23441-5S5472683
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