3,337 research outputs found
Physical Adversarial Attacks Against End-to-End Autoencoder Communication Systems
We show that end-to-end learning of communication systems through deep neural
network (DNN) autoencoders can be extremely vulnerable to physical adversarial
attacks. Specifically, we elaborate how an attacker can craft effective
physical black-box adversarial attacks. Due to the openness (broadcast nature)
of the wireless channel, an adversary transmitter can increase the
block-error-rate of a communication system by orders of magnitude by
transmitting a well-designed perturbation signal over the channel. We reveal
that the adversarial attacks are more destructive than jamming attacks. We also
show that classical coding schemes are more robust than autoencoders against
both adversarial and jamming attacks. The codes are available at [1].Comment: to appear at IEEE Communications Letter
An Empirical Analysis of Imports of Iran: Are Imports, Exchange Rate and GDP Cointegrated?
This paper investigates the effect of exchange rate and other variables such as world GDP, domestic GDP and Inflation on Iran’s Imports using cointegration method suggested by Gregory and Hansen. The empirical analysis indicates that there is a long run relationship between imports and these variables as they are cointegrated and there is an evidence of a structural shift during 1995. The empirical results indicate that the variables have expected signs. In view of these findings some policy suggestions have been made
The main transition in the Pink membrane model: finite-size scaling and the influence of surface roughness
We consider the main transition in single-component membranes using computer
simulations of the Pink model [D. Pink {\it et al.}, Biochemistry {\bf 19}, 349
(1980)]. We first show that the accepted parameters of the Pink model yield a
main transition temperature that is systematically below experimental values.
This resolves an issue that was first pointed out by Corvera and co-workers
[Phys. Rev. E {\bf 47}, 696 (1993)]. In order to yield the correct transition
temperature, the strength of the van der Waals coupling in the Pink model must
be increased; by using finite-size scaling, a set of optimal values is
proposed. We also provide finite-size scaling evidence that the Pink model
belongs to the universality class of the two-dimensional Ising model. This
finding holds irrespective of the number of conformational states. Finally, we
address the main transition in the presence of quenched disorder, which may
arise in situations where the membrane is deposited on a rough support. In this
case, we observe a stable multi-domain structure of gel and fluid domains, and
the absence of a sharp transition in the thermodynamic limit.Comment: submitted to PR
Thermodynamics of string black hole with hyperscaling violation
In this paper, we start with black brane and construct specific space-time
which violates hyperscaling. In order to obtain the string solution we apply
Null-Melvin-Twist and -reduction. By using the difference action method we
study thermodynamics of system to obtain Hawking-Page phase transition. In
order to have hyperscaling violation we need to consider
In that case the free energy is always negative and our solution is thermal
radiation without a black hole. Therefore we find that there is not any
Hawking-Page transition. Also, we discuss the stability of system and all
thermodynamical quantities.Comment: 12 pages. Accepted for publication in EPJ
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