29,759 research outputs found
Successive Wyner-Ziv Coding Scheme and its Application to the Quadratic Gaussian CEO Problem
We introduce a distributed source coding scheme called successive Wyner-Ziv
coding. We show that any point in the rate region of the quadratic Gaussian CEO
problem can be achieved via the successive Wyner-Ziv coding. The concept of
successive refinement in the single source coding is generalized to the
distributed source coding scenario, which we refer to as distributed successive
refinement. For the quadratic Gaussian CEO problem, we establish a necessary
and sufficient condition for distributed successive refinement, where the
successive Wyner-Ziv coding scheme plays an important role.Comment: 28 pages, submitted to the IEEE Transactions on Information Theor
Multiple Description Quantization via Gram-Schmidt Orthogonalization
The multiple description (MD) problem has received considerable attention as
a model of information transmission over unreliable channels. A general
framework for designing efficient multiple description quantization schemes is
proposed in this paper. We provide a systematic treatment of the El Gamal-Cover
(EGC) achievable MD rate-distortion region, and show that any point in the EGC
region can be achieved via a successive quantization scheme along with
quantization splitting. For the quadratic Gaussian case, the proposed scheme
has an intrinsic connection with the Gram-Schmidt orthogonalization, which
implies that the whole Gaussian MD rate-distortion region is achievable with a
sequential dithered lattice-based quantization scheme as the dimension of the
(optimal) lattice quantizers becomes large. Moreover, this scheme is shown to
be universal for all i.i.d. smooth sources with performance no worse than that
for an i.i.d. Gaussian source with the same variance and asymptotically optimal
at high resolution. A class of low-complexity MD scalar quantizers in the
proposed general framework also is constructed and is illustrated
geometrically; the performance is analyzed in the high resolution regime, which
exhibits a noticeable improvement over the existing MD scalar quantization
schemes.Comment: 48 pages; submitted to IEEE Transactions on Information Theor
Comparison of instrumental methods for measuring seed hardness of food-grade soybean
Seed hardness is an important factor in determining soybean suitability for natto production. There is no established methodology for testing seed texture of soybeans. The objective of this study was to develop an efficient method by examining different instruments and seed parameters that could be potentially used for testing soybean seed hardness. Five food-grade soybean genotypes with different seed sizes were used to determine seed hardness and water-absorption capacity. Water absorption capacity was expressed by swell ratios for seed weight, seed dimension, and volume of water changes before and after soaking. Seed hardness test was conducted by a one-bite method using two food-texture analyzers: a TMS-2000 equipped with shear cell (SC) and a TA-XT2i equipped with either a single blade (SB), a 2-mm probe (PB), a 75-mm cylinder (CY), or a 16-probe pea rigs (PR). The results showed that hardness testing by CY with ten seeds (CV=0.14), SB with 5 seeds (CV=0.11), and SC with 30 g steamed seeds (CV=0.14) produced dependable and consistent results with low coefficient of variance. However, SC may not be practical for early plant selection in a breeding program due to a relatively large sample requirement. Seed size was negatively, whereas swell ratio by weight and volume was positively, correlated with seed hardness, and therefore, can be used as indirect selection indicators for seed hardness
Interpretations and Implications of the Top Quark Rapidity Asymmetries and
Forward-backward asymmetries and are observed in the
top quark rapidity distribution and in the rapidity distribution of charged
leptons from top quark decay at the Tevatron proton-antiproton collider,
and a charge asymmetry is seen in proton-proton collisions at the Large
Hadron Collider (LHC). In this paper, we update our previous studies of the
Tevatron asymmetries using the most recent data. We provide expectations for
at the LHC based first on model independent extrapolations from the
Tevatron, and second based on new physics models that can explain the Tevatron
asymmetries. We examine the relationship of the two asymmetries and
. We show their connection through the spin correlation
between the charged lepton and the top quark with different polarization
states. We show that the ratio of the two asymmetries provides independent
insight into new physics models that are invoked to fit the top quark
asymmetry. We emphasize the value of the measurement of both asymmetries, and
we conclude that a model which produces more right-handed than left-handed top
quarks is favored by the present Tevatron data.Comment: Some figures changed. A typo in appendix fixed. Published in Physical
Review
Top Quark Polarization As A Probe of Models with Extra Gauge Bosons
New heavy gauge bosons exist in many models of new physics beyond the
standard model of particle physics. Discovery of these W^\prime and Z^\prime
resonances and the establishment of their spins, couplings, and other quantum
numbers would shed light on the gauge structure of the new physics. The
measurement of the polarization of the SM fermions from the gauge boson decays
would decipher the handedness of the coupling of the new states, an important
relic of the primordial new physics symmetry. Since the top quark decays
promptly, its decay preserves spin information. We show how decays of new gauge
bosons into third generation fermions (W^\prime \to tb, Z^\prime\to t\bar{t})
can be used to determine the handedness of the couplings of the new states and
to discriminate among various new physics models
Top Quark Forward-Backward Asymmetry and Same-Sign Top Quark Pairs
The top quark forward-backward asymmetry measured at the Tevatron collider
shows a large deviation from standard model expectations. Among possible
interpretations, a non-universal model is of particular interest as
it naturally predicts a top quark in the forward region of large rapidity. To
reproduce the size of the asymmetry, the couplings of the to
standard model quarks must be large, inevitably leading to copious production
of same-sign top quark pairs at the energies of the Large Hadron Collider
(LHC). We explore the discovery potential for and production in
early LHC experiments at 7-8 TeV and conclude that if {\it no} signal is
observed with 1 fb of integrated luminosity, then a non-universal
alone cannot explain the Tevatron forward-backward asymmetry.Comment: Tevatron limit from same-sign tt search adde
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