Gyroscope precession along general timelike geodesics in a Kerr black hole spacetime

The precession angular velocity of a gyroscope moving along a general geodesic in the Kerr spacetime is analyzed using the geometric properties of the spacetime. Natural frames along the gyroscope world line are explicitly constructed by boosting frames adapted to fundamental observers. A novel geometrical description is given to Marck's construction of a parallel propagated orthonormal frame along a general geodesic, identifying and clarifying the special role played by the Carter family of observers in this general context, thus extending previous discussion for the equatorial plane case.

Hyperbolic-like elastic scattering of spinning particles by a Schwarzschild black hole

The scattering of spinning test particles by a Schwarzschild black hole is studied. The motion is described according to the Mathisson-Papapetrou-Dixon model for extended bodies in a given gravitational background field. The equatorial plane is taken as the orbital plane, the spin vector being orthogonal to it with constant magnitude. The equations of motion are solved analytically in closed form to first-order in spin and the solution is used to compute corrections to the standard geodesic scattering angle as well as capture cross section by the black hole.

Exploring and analyzing the tor hidden services graph

The exploration and analysis of Web graphs has flourished in the recent past, producing a large number of relevant and interesting research results. However, the unique characteristics of the Tor network limit the applicability of standard techniques and demand for specific algorithms to explore and analyze it. The attention of the research community has focused on assessing the security of the Tor infrastructure (i.e., its ability to actually provide the intended level of anonymity) and on discussing what Tor is currently being used for.

Deviation and precession effects in the field of a weak gravitational wave

Deviation and precession effects of a bunch of spinning particles in the field of a weak gravitational plane wave are studied according to the Mathisson-Papapetrou-Dixon (MPD) model. Before the passage of the wave the particles are at rest with an associated spin vector aligned along a given direction with constant magnitude. The interaction with the gravitational wave causes the particles to keep moving on the 2-plane orthogonal to the direction of propagation of the wave, with the transverse spin vector undergoing oscillations around the initial orientation.

CoLLIDE: CLoud Latency-based IDEntification

As services steadily migrate to the Cloud, the availability of an overarching identity framework has become a stringent need. Moreover, such an identity framework is now critical in the Internet of Things. To address this problem, identification solutions have been proposed in the past leveraging software or hardware properties of devices. While those solutions proved feasible, their root of trust was based either within the device or in a remote server.

HyBIS: Advanced introspection for effective windows guest protection

Effectively protecting the WindowsTM OS is a challenging task, since most implementation details are not publicly known. Windows OS has always been the main target of malware that have exploited numerous bugs and vulnerabilities exposed by its implementations. Recent trusted boot and additional integrity checks have rendered the Windows OS less vulnerable to kernel-level rootkits. Nevertheless, guest Windows Virtual Machines are becoming an increasingly interesting attack target.

A multi-origin and multi-destination orienteering problem to manage emergency situations

ThŒe emergencies management in industrial plants is an issue widely discussed in the literature and in the European legislative framework. Despite the large interest shown by the di‚erent actors involved in emergencies management, neither scienti€c nor in industrial €eld, have developed intelligent tools to support the decisions in these particular contexts.

Experimenting an Artificial Bee Colony algorithm to approach the capacitated vehicle routing problem

ThŒis paper is focused on the comparison of results obtained by the resolution of the capacitated vehicle routing problem. A modi€ed algorithm of classical arti€cial bee colony (ABC) is described and implemented in this article, in particular, a new type of neighborhood operator is introduced. Œe idea on the base of ABC is creating an algorithm of Swarm - Intelligence which mimics the behavior of a honey bee swarm.

Mechanisms and nucleation rate of methane hydrate by dynamical nonequilibrium molecular dynamics

We investigate the effects of high solvated-methane concentration on methane-hydrate nucleation at 250 K and 500 atm. We consider solutions at four levels of methane molar fraction in the initial H2O-CH4 solution, ?CH4 = 0.038, 0.044, 0.052, and 0.058, which are higher than (metastable) bulk supersaturation. ?CH4 is controlled independently of the temperature and pressure thanks to the use of special simulation techniques [Phys. Chem. Chem. Phys. 2011, 13, 13177].