22,739 research outputs found
Self-Tuning and de Sitter Brane Intersections in the 6-Dimensional Brane Models
We study the self-tuning of general brane junctions and brane networks on the
6-dimensional space-time. For the general brane junctions, there may exist one
fine-tuning among the brane tensions. For the brane networks, similar to the
5-dimensional self-tuning brane models, the brane tensions can be set
arbitrarily and there exists the singularity for the metric and bulk scalar.
And if we want to regularize the singularity, we will introduce the fine-tuning
among the brane tensions. In addition, because the 4-dimensional cosmological
constant we observe may be positive and very small, we discuss the brane
network with de Sitter brane intersections by introducing a bulk scalar.Comment: Latex, 11 page
Iterative Soft Input Soft Output Decoding of Reed-Solomon Codes by Adapting the Parity Check Matrix
An iterative algorithm is presented for soft-input-soft-output (SISO)
decoding of Reed-Solomon (RS) codes. The proposed iterative algorithm uses the
sum product algorithm (SPA) in conjunction with a binary parity check matrix of
the RS code. The novelty is in reducing a submatrix of the binary parity check
matrix that corresponds to less reliable bits to a sparse nature before the SPA
is applied at each iteration. The proposed algorithm can be geometrically
interpreted as a two-stage gradient descent with an adaptive potential
function. This adaptive procedure is crucial to the convergence behavior of the
gradient descent algorithm and, therefore, significantly improves the
performance. Simulation results show that the proposed decoding algorithm and
its variations provide significant gain over hard decision decoding (HDD) and
compare favorably with other popular soft decision decoding methods.Comment: 10 pages, 10 figures, final version accepted by IEEE Trans. on
Information Theor
Finding Relevant Answers in Software Forums
AbstractāOnline software forums provide a huge amount of valuable content. Developers and users often ask questions and receive answers from such forums. The availability of a vast amount of thread discussions in forums provides ample opportunities for knowledge acquisition and summarization. For a given search query, current search engines use traditional information retrieval approach to extract webpages containin
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