Adaptive just-in-time code diversification

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

PSR B0826-34: Sometimes a rotating radio transient

We report on the detection of sporadic, strong single pulses co-existing with a periodic weak emission in the duration of weak mode of PSR B0826-34. The intensities and durations of these pulses are comparable with that of the sub-pulses in the strong mode, and these pulses are distributed within the phase ranges of the main-pulse and interpulse of the strong-mode average profile. These results suggest that there are most possibly sporadic, very short timescale turn-on of strong-mode emission during the weak-mode state of the pulsar. The emission features of the bursts of strong pulses of PSR B0826-34 during its weak-mode state are similar to those of the rotating radio transients (RRATs). PSR B0826-34 is the second pulsar known which oscillates between pulsar-like and RRAT-like modes.Comment: 11 pages, 4 figures; 2012, ApJ, 759, L

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

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, $10^3$ to $10^4$ 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

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

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 $L^q$ with $2<q\le\infty$, 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 $L^\infty$, an explicit convergence rate is obtained