9,974 research outputs found
Laundering Money Online: a review of cybercriminals methods
Money laundering is a critical step in the cyber crime process which is
experiencing some changes as hackers and their criminal colleagues continually
alter and optimize payment mechanisms. Conducting quantitative research on
underground laundering activity poses an inherent challenge: Bad guys and their
banks do not share information on criminal pursuits. However, by analyzing
forums, we have identified two growth areas in money laundering: online gaming
and micro laundering.Comment: Industry report, White paper. Tools and Resources for Anti-Corruption
Knowledge, June, 01, 2013. United Nations Office on Drugs and Crime (UNODC
Lax equations in ten dimensional supersymmetric classical Yang-Mills theories
In a recent paper (hep-th/9811108), Saveliev and the author showed that there
exits an on-shell light cone gauge where the non-linear part of the field
equations reduces to a (super) version of Yang's equations which may be solved
by methods inspired by the ones previously developed for self-dual Yang-Mills
equations in four dimensions. Here, the analogy between these latter theories
and the present ones is pushed further by writing down a set of super partial
linear differential equations whose consistency conditions may be derived from
the SUSY Y-M equations in ten dimensions, and which are the analogues of the
Lax pair of Belavin and Zakharov. On the simplest example of the two pole
ansatz, it is shown that the same solution-generating techniques are at work,
as for the derivation of the celebrated multi-instanton solutions carried out
in the late seventies. The present Lax representation, however, is only a
consequence of (instead of being equivalent to) the field equations, in
contrast with the Belavin Zakharov Lax pair.Comment: 8 pages Late
Integrable structures in classical off-shell 10D supersymmetric Yang-Mills theory
The superspace flatness conditions which are equivalent to the field
equations of supersymmetric Yang-Mills theory in ten dimensions have not been
useful so far to derive non trivial classical solutions. Recently, modified
flatness conditions were proposed, which are explicitly integrable
(hep-th/9811108), and are based on the breaking of symmetry SO(9,1) ->
SO(2,1)xSO(7). In this article, we investigate their physical content. To this
end, group-algebraic methods are developed which allow to derive the set of
physical fields and their equations of motion from the superfield expansion of
the supercurl, systematically.
A set of integrable superspace constraints is identified which drastically
reduces the field content of the unconstrained superfield but leaves the
spectrum including the original Yang-Mills vector field completely off-shell. A
weaker set of constraints gives rise to additional fields obeying first order
differential equations. Geometrically, the SO(7) covariant superspace
constraints descend from a truncation of Witten's original linear system to
particular one-parameter families of light-like rays.Comment: 43 pages, 4 figures. Improved version for publicatio
From Single-thread to Multithreaded: An Efficient Static Analysis Algorithm
A great variety of static analyses that compute safety properties of
single-thread programs have now been developed. This paper presents a
systematic method to extend a class of such static analyses, so that they
handle programs with multiple POSIX-style threads. Starting from a pragmatic
operational semantics, we build a denotational semantics that expresses
reasoning a la assume-guarantee. The final algorithm is then derived by
abstract interpretation. It analyses each thread in turn, propagating
interferences between threads, in addition to other semantic information. The
combinatorial explosion, ensued from the explicit consideration of all
interleavings, is thus avoided. The worst case complexity is only increased by
a factor n compared to the single-thread case, where n is the number of
instructions in the program. We have implemented prototype tools, demonstrating
the practicality of the approach
On the Decades-Long Stability of the Interstellar Wind through the Solar System
We have revisited the series of observations recently used to infer a
temporal variation of the interstellar helium flow over the last forty years.
Concerning the recent IBEX-Lo direct detection of Helium neutrals, there are
two types of precise and unambiguous measurements which do not rely on the
exact response of the instrument: the count rate maxima as a function of the
spin angle, which determines the ecliptic latitude of the flow, and the count
rate maxima as a function of IBEX longitude, which determines a tight
relationship between the ecliptic longitude of the flow and its velocity far
from the Sun. These measurements provide parameters (and couples of parameters
in the second case) remarkably similar to the canonical, old values. In
contrast, the preferential choice of a lower velocity and higher longitude
reported before from IBEX data is based only on the count rate variation (at
each spin phase maximum) as a function of the satellite longitude, when
drifting across the region of high fluxes. We have examined the consequences of
dead time counting effects, and conclude that their inclusion at a realistic
level is sufficient to reconcile the data with the old parameters, calling for
further investigations. We discuss the analyses of the STEREO pickup ion (PUI)
data and argue that the statistical method that has been preferred to infer the
neutral flow longitude (instead of the more direct method based on the PUI
maximum flux directions), is not appropriate. Moreover, transport effects may
have been significant at the very weak solar activity level of 2007-2009, in
which case the longitudes of the PUI maxima are only upper limits on the flow
longitude. Finally, we found that the use of some flow longitude determinations
based on UV glow data are not adequate. At variance with recent conclusions we
find no evidence for a temporal variability of the interstellar helium flow.Comment: 8 pages, 3 figures, accepted for publication in Astronomy and
Astrophysic
Self-Recognition in Data Visualization: How People See Themselves in Social Visualizations
Self-recognition is an intimate act performed by people. Inspired by Paul Ricoeur, we reflect upon the action of self-recognition, especially when data visualization represents the observer itself. Along the article, the reader is invited to think about this specific relationship through concepts like the personal identity stored in information systems, the truthfulness at the core of self-recognition, and the mutual-recognition among community members. In the context of highly interdisciplinary research, we unveil two protagonists in data visualization: the designer and the observer - the designer as the creator and the observer as the viewer of a visualization. This article deals with some theoretical aspects behind data visualization, a discipline more complex than normally expected. We believe that data visualization deserves a conceptual framework, and this investigation pursues this intention. For this reason, we look at the designer as not just a technician in the visualization production, but as a contemporary ethnologist - the designer as a professional working in a social environment to comprehend the context and formulate a specific inquiry with the help of appropriate visual languages
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