1,316 research outputs found
Finite-Dimensional Representations of the Quantum Superalgebra U[gl(2/2)]: I. Typical representations at generic
In the present paper we construct all typical finite-dimensional
representations of the quantum Lie superalgebra at generic
deformation parameter . As in the non-deformed case the finite-dimensional
-module obtained is irreducible and can be decomposed
into finite-dimensional irreducible -submodules
Comment: published version. Some formulae are rewritten in more compact for
Irreducible representations of Upq[gl(2/2)]
The two-parametric quantum superalgebra and its
representations are considered. All finite-dimensional irreducible
representations of this quantum superalgebra can be constructed and classified
into typical and nontypical ones according to a proposition proved in the
present paper. This proposition is a nontrivial deformation from the one for
the classical superalgebra gl(2/2), unlike the case of one-parametric
deformations.Comment: Latex, 8 pages. A reference added in v.
Deceiving Google's Cloud Video Intelligence API Built for Summarizing Videos
Despite the rapid progress of the techniques for image classification, video
annotation has remained a challenging task. Automated video annotation would be
a breakthrough technology, enabling users to search within the videos.
Recently, Google introduced the Cloud Video Intelligence API for video
analysis. As per the website, the system can be used to "separate signal from
noise, by retrieving relevant information at the video, shot or per frame"
level. A demonstration website has been also launched, which allows anyone to
select a video for annotation. The API then detects the video labels (objects
within the video) as well as shot labels (description of the video events over
time). In this paper, we examine the usability of the Google's Cloud Video
Intelligence API in adversarial environments. In particular, we investigate
whether an adversary can subtly manipulate a video in such a way that the API
will return only the adversary-desired labels. For this, we select an image,
which is different from the video content, and insert it, periodically and at a
very low rate, into the video. We found that if we insert one image every two
seconds, the API is deceived into annotating the video as if it only contained
the inserted image. Note that the modification to the video is hardly
noticeable as, for instance, for a typical frame rate of 25, we insert only one
image per 50 video frames. We also found that, by inserting one image per
second, all the shot labels returned by the API are related to the inserted
image. We perform the experiments on the sample videos provided by the API
demonstration website and show that our attack is successful with different
videos and images
Finite-Dimensional Representations of the Quantum Superalgebra U[gl(2/2)]: II. Nontypical representations at generic
The construction approach proposed in the previous paper Ref. 1 allows us
there and in the present paper to construct at generic deformation parameter
all finite--dimensional representations of the quantum Lie superalgebra
. The finite--dimensional -modules
constructed in Ref. 1 are either irreducible or indecomposible. If a module
is indecomposible, i.e. when the condition (4.41) in Ref. 1 does not
hold, there exists an invariant maximal submodule of , to say
, such that the factor-representation in the factor-module
is irreducible and called nontypical. Here, in this paper,
indecomposible representations and nontypical finite--dimensional
representations of the quantum Lie superalgebra are considered
and classified as their module structures are analized and the matrix elements
of all nontypical representations are written down explicitly.Comment: Latex file, 49 page
US monetary policy uncertainty drives global business cycles
Though the reactions of economic activities in the US and globally to FED policy are well documented, the global impacts of unexpected changes in the US monetary policy uncertainty are still less understood. Povilas Lastauskas and Anh D. M. Nguyen highlight the role of uncertainty in generating synchronised worldwide contraction and rationalising the global economy’s slow recovery from global financial crisis. Despite [...
Retrieval of interatomic separations of molecules from laser-induced high-order harmonic spectra
We illustrate an iterative method for retrieving the internuclear separations
of N, O and CO molecules using the high-order harmonics generated
from these molecules by intense infrared laser pulses. We show that accurate
results can be retrieved with a small set of harmonics and with one or few
alignment angles of the molecules. For linear molecules the internuclear
separations can also be retrieved from harmonics generated using isotropically
distributed molecules. By extracting the transition dipole moment from the
high-order harmonic spectra, we further demonstrated that it is preferable to
retrieve the interatomic separation iteratively by fitting the extracted dipole
moment. Our results show that time-resolved chemical imaging of molecules using
infrared laser pulses with femtosecond temporal resolutions is possible.Comment: 14 pages, 9 figure
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