8,609 research outputs found
A note on characterization of Moishezon spaces
In this note a necessary and sufficient condition for a compact complex space X t.o be Moishezon is obtained; it can be seen as the existente of a line bundle L on X such that, for some point x Є X, the first cohomology groups of X with values respectively in [Fórmula disponible al document original]
Simulation of mirror inversion of quantum states in an XY spin chain using NMR
We report an experimental quantum simulation of unitary dynamics of an XY
spin chain with pre-engineered couplings. Using this simulation, we demonstrate
the mirror inversion of quantum states, proposed by Albanese et al. [Phys. Rev.
Lett. 93, 230502 (2004)]. The experiment is performed with a 5-qubit dipolar
coupled spin system using nuclear magnetic resonance techniques. To perform
quantum simulation we make use of the recently proposed unitary operator
decomposition algorithm of Ajoy et al. [Phys. Rev. A 85, 030303 (2012)] along
with numerical pulse optimization techniques. Further, using mirror inversion,
we demonstrate that entangled states can be transferred from one end of the
chain to the other end. The simulations are implemented with high experimental
fidelity, which implies that these kind of simulations may be possible in
larger systems.Comment: 9 pages, 6 figure
Flooding attacks to internet threat monitors (ITM): Modeling and counter measures using botnet and honeypots
The Internet Threat Monitoring (ITM),is a globally scoped Internet monitoring
system whose goal is to measure, detect, characterize, and track threats such
as distribute denial of service(DDoS) attacks and worms. To block the
monitoring system in the internet the attackers are targeted the ITM system. In
this paper we address flooding attack against ITM system in which the attacker
attempt to exhaust the network and ITM's resources, such as network bandwidth,
computing power, or operating system data structures by sending the malicious
traffic. We propose an information-theoretic frame work that models the
flooding attacks using Botnet on ITM. Based on this model we generalize the
flooding attacks and propose an effective attack detection using Honeypots
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