6,641 research outputs found
Jar Decoding: Non-Asymptotic Converse Coding Theorems, Taylor-Type Expansion, and Optimality
Recently, a new decoding rule called jar decoding was proposed; under jar
decoding, a non-asymptotic achievable tradeoff between the coding rate and word
error probability was also established for any discrete input memoryless
channel with discrete or continuous output (DIMC). Along the path of
non-asymptotic analysis, in this paper, it is further shown that jar decoding
is actually optimal up to the second order coding performance by establishing
new non-asymptotic converse coding theorems, and determining the Taylor
expansion of the (best) coding rate of finite block length for
any block length and word error probability up to the second
order. Finally, based on the Taylor-type expansion and the new converses, two
approximation formulas for (dubbed "SO" and "NEP") are
provided; they are further evaluated and compared against some of the best
bounds known so far, as well as the normal approximation of
revisited recently in the literature. It turns out that while the normal
approximation is all over the map, i.e. sometime below achievable bounds and
sometime above converse bounds, the SO approximation is much more reliable as
it is always below converses; in the meantime, the NEP approximation is the
best among the three and always provides an accurate estimation for . An important implication arising from the Taylor-type expansion of
is that in the practical non-asymptotic regime, the optimal
marginal codeword symbol distribution is not necessarily a capacity achieving
distribution.Comment: submitted to IEEE Transaction on Information Theory in April, 201
Extremal RN/CFT in Both Hands Revisited
We study RN/CFT correspondence for four dimensional extremal
Reissner-Nordstrom black hole. We uplift the 4d RN black hole to a 5d rotating
black hole and make a geometric regularization of the 5d space-time. Both hands
central charges are obtained correctly at the same time by Brown-Henneaux
technique.Comment: 10 pages, no figur
Crystal structure of the 3C protease from South African Territories type 2 foot-and-mouth disease virus
The replication of foot-and-mouth disease virus (FMDV) is dependent on the virus-encoded 3C protease (3Cpro). As in other picornaviruses, 3Cpro performs most of the proteolytic processing of the polyprotein expressed from the single open reading frame in the RNA genome of the virus. Previous work revealed that the 3Cpro from serotype A – one of the seven serotypes of FMDV – adopts a trypsin-like fold. Phylogenetically the FMDV serotypes are grouped into two clusters, with O, A, C, and Asia 1 in one, and the three South African Territories serotypes, (SAT-1, SAT-2 and SAT-3) in another. We report here the cloning, expression and purification of 3C proteases from four SAT serotype viruses (SAT2/GHA/8/91, SAT1/NIG/5/81, SAT1/UGA/1/97, and SAT2/ZIM/7/83) and the crystal structure at 3.2 Å resolution of 3Cpro from SAT2/GHA/8/91)
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