80,314 research outputs found
Fast Min-Sum Algorithms for Decoding of LDPC over GF(q)
In this paper, we present a fast min-sum algorithm for decoding LDPC codes
over GF(q). Our algorithm is different from the one presented by David Declercq
and Marc Fossorier in ISIT 05 only at the way of speeding up the horizontal
scan in the min-sum algorithm. The Declercq and Fossorier's algorithm speeds up
the computation by reducing the number of configurations, while our algorithm
uses the dynamic programming instead. Compared with the configuration reduction
algorithm, the dynamic programming one is simpler at the design stage because
it has less parameters to tune. Furthermore, it does not have the performance
degradation problem caused by the configuration reduction because it searches
the whole configuration space efficiently through dynamic programming. Both
algorithms have the same level of complexity and use simple operations which
are suitable for hardware implementations.Comment: Accepted by IEEE Information Theory Workshop, Chengdu, China, 200
MSSM Anatomy of the Polarization Puzzle in B --> phi K* Decays
We analyze the polarization puzzle in the Minimal
Supersymmetric Standard Model (MSSM) including the neutral Higgs boson (NHB)
contributions. To calculate the non-factorizable contributions to hadronic
matrix elements of operators, we have used the QCD factorization framework to
the order. It is shown that the recent experimental results of the
polarization fractions in decays, which are difficult to be
explained in SM, could be explained in MSSM if there are flavor non-diagonal
squark mass matrix elements of 2nd and 3rd generations, which also satisfy all
relevant constraints from known experiments (, etc.). We have shown
in details that the experimental results can be accommodated with the flavor
non-diagonal mass insertion of chirality RL, RL+LR, RR, or LL+ RR when the NHB
contributions as well as corrections of hadronic matrix
elements of operators are included. However the branching ratios for the decay
are smaller than the experimental measurements.Comment: 15 pages, 5 figures, minor revision and references adde
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