14,177 research outputs found

    Adaptive just-in-time code diversification

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    We present a method to regenerate diversified code dynamically in a Java bytecode JIT compiler, and to update the diversification frequently during the execution of the program. This way, we can significantly reduce the time frame in which attackers can let a program leak useful address space information and subsequently use the leaked information in memory exploits. A proof of concept implementation is evaluated, showing that even though code is recompiled frequently, we can achieved smaller overheads than the previous state of the art, which generated diversity only once during the whole execution of a program

    β\beta-decay half-lives of neutron-rich nuclei and matter flow in the rr-process

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    The β\beta-decay half-lives of neutron-rich nuclei with 20⩽Z⩽5020 \leqslant Z \leqslant 50 are systematically investigated using the newly developed fully self-consistent proton-neutron quasiparticle random phase approximation (QRPA), based on the spherical relativistic Hartree-Fock-Bogoliubov (RHFB) framework. Available data are reproduced by including an isospin-dependent proton-neutron pairing interaction in the isoscalar channel of the RHFB+QRPA model. With the calculated β\beta-decay half-lives of neutron-rich nuclei a remarkable speeding up of rr-matter flow is predicted. This leads to enhanced rr-process abundances of elements with A≳140A \gtrsim 140, an important result for the understanding of the origin of heavy elements in the universe.Comment: 14 pages, 4 figure

    Vanishing viscosity limits for the degenerate lake equations with Navier boundary conditions

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    The paper is concerned with the vanishing viscosity limit of the two-dimensional degenerate viscous lake equations when the Navier slip conditions are prescribed on the impermeable boundary of a simply connected bounded regular domain. When the initial vorticity is in the Lebesgue space LqL^q with 2<q≤∞2<q\le\infty, we show the degenerate viscous lake equations possess a unique global solution and the solution converges to a corresponding weak solution of the inviscid lake equations. In the special case when the vorticity is in L∞L^\infty, an explicit convergence rate is obtained

    High-speed measurement of rotational anisotropy nonlinear optical harmonic generation using position sensitive detection

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    We present a method of performing high-speed rotational anisotropy nonlinear optical harmonic generation experiments at rotational frequencies of several hertz by projecting the harmonic light reflected at different angles from a sample onto a stationary position sensitive detector. The high rotational speed of the technique, 10310^3 to 10410^4 times larger than existing methods, permits precise measurements of the crystallographic and electronic symmetries of samples by averaging over low frequency laser power, beam pointing, and pulse width fluctuations. We demonstrate the sensitivity of our technique by resolving the bulk four-fold rotational symmetry of GaAs about its [001] axis using second harmonic generation
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