2,432 research outputs found
Locational wireless and social media-based surveillance
The number of smartphones and tablets as well as the volume of traffic generated by these devices has been growing constantly over the past decade and this growth is predicted to continue at an increasing rate over the next five years. Numerous native features built into contemporary smart devices enable highly accurate digital fingerprinting techniques. Furthermore, software developers have been taking advantage of locational capabilities of these devices by building applications and social media services that enable convenient sharing of information tied to geographical locations. Mass online sharing resulted in a large volume of locational and personal data being publicly available for extraction. A number of researchers have used this opportunity to design and build tools for a variety of uses – both respectable and nefarious. Furthermore, due to the peculiarities of the IEEE 802.11 specification, wireless-enabled smart devices disclose a number of attributes, which can be observed via passive monitoring. These attributes coupled with the information that can be extracted using social media APIs present an opportunity for research into locational surveillance, device fingerprinting and device user identification techniques. This paper presents an in-progress research study and details the findings to date
Verification of primitive Sub-Ghz RF replay attack techniques based on visual signal analysis
As the low-cost options for radio traffic capture, analysis and transmission are becoming available, some security researchers have developed open-source tools that potentially make it easier to assess the security of the devices that rely on radio communications without the need for extensive knowledge and understanding of the associated concepts. Recent research in this area suggests that primitive visual analysis techniques may be applied to decode selected radio signals successfully. This study builds upon the previous research in the area of sub-GHz radio communications and aims to outline the associated methodology as well as verify some of the reported techniques for carrying out radio frequency replay attacks using low-cost materials and freely available software
A Grand Old Church Rose in the East: The Church of God in Christ (COGIC) in East Texas
This essay traces the history of the Church of God in Christ and its early beginnings in East Texas
Strong quantum effects in an almost classical antiferromagnet on a kagome lattice
Two ubiquitous features of frustrated spin systems stand out: massive
degeneracy of their ground states and flat, or dispersionless, excitation
branches. In real materials, the former is frequently lifted by secondary
interactions or quantum fluctuations, in favor of an ordered or spin-liquid
state, but the latter often survive. We demonstrate that flat modes may
precipitate remarkably strong quantum effects even in the systems that are
otherwise written off as almost entirely classical. The resultant spectral
features should be reminiscent of the quasiparticle breakdown in quantum
systems, only here the effect is strongly amplified by the flatness of
spin-excitation branches, leading to the damping that is not vanishingly small
even at . We provide a theoretical analysis of excitation spectrum
of the iron-jarosite to illustrate our findings and to suggest further
studies of this and other frustrated spin systems.Comment: 7 pages, accepted to PR
The zombies strike back: Towards client-side beef detection
A web browser is an application that comes bundled with every consumer operating system, including both desktop and mobile platforms. A modern web browser is complex software that has access to system-level features, includes various plugins and requires the availability of an Internet connection. Like any multifaceted software products, web browsers are prone to numerous vulnerabilities. Exploitation of these vulnerabilities can result in destructive consequences ranging from identity theft to network infrastructure damage. BeEF, the Browser Exploitation Framework, allows taking advantage of these vulnerabilities to launch a diverse range of readily available attacks from within the browser context. Existing defensive approaches aimed at hardening network perimeters and detecting common threats based on traffic analysis have not been found successful in the context of BeEF detection. This paper presents a proof-of-concept approach to BeEF detection in its own operating environment – the web browser – based on global context monitoring, abstract syntax tree fingerprinting and real-time network traffic analysis
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Rethinking α-RuCl3
We argue that several empirical constraints strongly restrict parameters of the effective microscopic spin model describing α-RuCl3. In particular, such constraints dictate a substantial positive off-diagonal anisotropic coupling Γ′>0, not anticipated previously. The renormalization by quantum fluctuations allows to reconcile larger values of the advocated bare parameters with their earlier assessments and provides a consistent description of the field evolution of spin excitations in the paramagnetic phase. We assert that large anisotropic terms inevitably result in strong anharmonic coupling of magnons, necessarily leading to broad features in their spectra due to decays, in accord with the observations in α-RuCl3. Using duality transformations, we explain the origin of the pseudo-Goldstone mode that is ubiquitous to the studied parameter space and is present in α-RuCl3. Our analysis offers a description of α-RuCl3 as an easy-plane ferromagnet with antiferromagnetic further-neighbor and strong off-diagonal couplings, which is in a fluctuating zigzag ground state proximate to an incommensurate phase that is continuously connected to a ferromagnetic one
Charge Stripe in an Antiferromagnet: 1d Band of Composite Excitations
With the help of analytical and numerical studies of the - model we
argue that the charge stripe in an antiferromagnetic insulator should be
understood as a system of holon-spin-polaron excitations condensed at the
self-induced antiphase domain wall. The structure of such a charge excitation
is studied in detail with numerical and analytical results for various
quantities being in a very close agreement. An analytical picture of these
excitations occupying an effective 1D stripe band is also in a very good accord
with numerical data. The emerging concept advocates the primary role of the
kinetic energy in favoring the stripe as a ground state. A comparative analysis
suggests the effect of pairing and collective meandering on the energetics of
the stripe formation to be secondary.Comment: 5 pages, 3 figures, proceedings of SCES'01 conference, Ann Arbor,
2001, to be published in Physica
Thermal conductivity in large- two-dimensional antiferromagnets: Role of phonon scattering
Motivated by the recent heat transport experiments in 2D antiferromagnets,
such as LaCuO, where the exchange coupling is larger than the Debye
energy , we discuss different types of relaxation processes for
magnon heat current with a particular focus on coupling to 3D phonons. We study
thermal conductivity by these in-plane magnetic excitations using two distinct
techniques, Boltzmann formalism within the relaxation-time approximation and
memory-function approach. Within these approaches, a close consideration is
given to the scattering of magnons by both acoustic and optical branches of
phonons. A remarkable accord between the two methods with regards to the
asymptotic behavior of the effective relaxation rates is demonstrated.
Additional scattering mechanisms, due to grain boundaries, impurities, and
finite correlation length in the paramagnetic phase, are discussed and included
in the calculations of the thermal conductivity . Again, we
demonstrate a close similarity of the results from the two techniques of
calculating . Our complementary approach strongly suggests that
scattering from optical or zone-boundary phonons is important for magnon heat
current relaxation in a high temperature window of .Comment: 21+ pages, 16 figure
The representations of the Hubbard algebra in terms of spin-fermion operators and motion of a hole in an antiferromagnetic state
The representation of the Hubbard operators in terms of the
spin operators and the fermion operator with spin
is proposed.
In the low-energy limit this representation is reduced to the representation
following from the Hubbard diagramm technique. In framework of this approach
motion of a hole in an antiferromagnetic state of the t-J model is considered.
It is shown that the primary hole energy is strongly renormalized and the band
width has an order of J rather than t.
The functional integral for the strongly correlated model induced by the
obtained representation is formulated. The representation of the total Hubbard
algebra for states in the lower and the upper Hubbard bands is formulated in
terms of the spin and two fermion fields with spin
is formulated.Comment: 12 pp. (LATEX
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