24,104 research outputs found
Interference Alignment for the Multi-Antenna Compound Wiretap Channel
We study a wiretap channel model where the sender has transmit antennas
and there are two groups consisting of and receivers respectively.
Each receiver has a single antenna. We consider two scenarios. First we
consider the compound wiretap model -- group 1 constitutes the set of
legitimate receivers, all interested in a common message, whereas group 2 is
the set of eavesdroppers. We establish new lower and upper bounds on the secure
degrees of freedom. Our lower bound is based on the recently proposed
\emph{real interference alignment} scheme. The upper bound provides the first
known example which illustrates that the \emph{pairwise upper bound} used in
earlier works is not tight.
The second scenario we study is the compound private broadcast channel. Each
group is interested in a message that must be protected from the other group.
Upper and lower bounds on the degrees of freedom are developed by extending the
results on the compound wiretap channel.Comment: Minor edits. Submitted to IEEE Trans. Inf. Theor
Data-Driven Chance Constrained Optimization under Wasserstein Ambiguity Sets
We present a data-driven approach for distributionally robust chance
constrained optimization problems (DRCCPs). We consider the case where the
decision maker has access to a finite number of samples or realizations of the
uncertainty. The chance constraint is then required to hold for all
distributions that are close to the empirical distribution constructed from the
samples (where the distance between two distributions is defined via the
Wasserstein metric). We first reformulate DRCCPs under data-driven Wasserstein
ambiguity sets and a general class of constraint functions. When the
feasibility set of the chance constraint program is replaced by its convex
inner approximation, we present a convex reformulation of the program and show
its tractability when the constraint function is affine in both the decision
variable and the uncertainty. For constraint functions concave in the
uncertainty, we show that a cutting-surface algorithm converges to an
approximate solution of the convex inner approximation of DRCCPs. Finally, for
constraint functions convex in the uncertainty, we compare the feasibility set
with other sample-based approaches for chance constrained programs.Comment: A shorter version is submitted to the American Control Conference,
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Continuous wavelet transform on local fields
The main objective of this paper is to define the mother wavelet on local
fields and study the continuous wavelet transform (CWT) and some of their basic
properties. its inversion formula, the Parseval relation and associated
convolution are also studied
A Search for the Higgs Boson in H->ZZ->2leptons 2jets Mode
A search for the Standard Model Higgs boson decaying to two Z bosons with
subsequent decay to a final state with two leptons and two quark-jets,
H->ZZ->2l 2jets, where \ell = e, {\mu}, is discussed. It is based on an
integrated luminosity of 1 fb-1 of proton-proton collision data at center of
mass energy sqrt(s) = 7 TeV collected by the CMS experiment at the LHC. The
data are compared to the expected Standard Model backgrounds. No evidence for
the Higgs boson is found and upper limits are placed on its production cross
section over the range of masses between 200 GeV and 600 GeV.Comment: To appear in the Proceedings of the DPF 2011 Conferenc
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