6,512 research outputs found
On Rigidity of hypersurfaces with constant curvature functions in warped product manifolds
In this paper, we first investigate several rigidity problems for
hypersurfaces in the warped product manifolds with constant linear combinations
of higher order mean curvatures as well as "weighted'' mean curvatures, which
extend the work \cite{Mon, Brendle,BE} considering constant mean curvature
functions. Secondly, we obtain the rigidity results for hypersurfaces in the
space forms with constant linear combinations of intrinsic Gauss-Bonnet
curvatures . To achieve this, we develop some new kind of Newton-Maclaurin
type inequalities on which may have independent interest.Comment: 24 pages, Ann. Glob. Anal. Geom. to appea
A Generic Transformation to Enable Optimal Repair in MDS Codes for Distributed Storage Systems
We propose a generic transformation that can convert any nonbinary
maximum distance separable (MDS) code into another MDS code
over the same field such that 1) some arbitrarily chosen nodes have the
optimal repair bandwidth and the optimal rebuilding access, 2) for the
remaining nodes, the normalized repair bandwidth and the normalized
rebuilding access (over the file size) are preserved, 3) the sub-packetization
level is increased only by a factor of . Two immediate applications of this
generic transformation are then presented. The first application is that we can
transform any nonbinary MDS code with the optimal repair bandwidth or the
optimal rebuilding access for the systematic nodes only, into a new MDS code
which possesses the corresponding repair optimality for all nodes. The second
application is that by applying the transformation multiple times, any
nonbinary scalar MDS code can be converted into an MDS code
with the optimal repair bandwidth and the optimal rebuilding access for all
nodes, or only a subset of nodes, whose sub-packetization level is also
optimal.Comment: This paper has been published in IEEE Transactions on Information
Theor
Exploring Lexical, Syntactic, and Semantic Features for Chinese Textual Entailment in NTCIR RITE Evaluation Tasks
We computed linguistic information at the lexical, syntactic, and semantic
levels for Recognizing Inference in Text (RITE) tasks for both traditional and
simplified Chinese in NTCIR-9 and NTCIR-10. Techniques for syntactic parsing,
named-entity recognition, and near synonym recognition were employed, and
features like counts of common words, statement lengths, negation words, and
antonyms were considered to judge the entailment relationships of two
statements, while we explored both heuristics-based functions and
machine-learning approaches. The reported systems showed robustness by
simultaneously achieving second positions in the binary-classification subtasks
for both simplified and traditional Chinese in NTCIR-10 RITE-2. We conducted
more experiments with the test data of NTCIR-9 RITE, with good results. We also
extended our work to search for better configurations of our classifiers and
investigated contributions of individual features. This extended work showed
interesting results and should encourage further discussion.Comment: 20 pages, 1 figure, 26 tables, Journal article in Soft Computing
(Spinger). Soft Computing, online. Springer, Germany, 201
Perturbative QCD analysis of Dalitz decays
In the framework of perturbative QCD, we study the Dalitz decays
with large recoil momentum.
Meanwhile, the soft contributions from the small recoil momentum region and the
VMD corrections have also been taken into account. The transition form factors
including the hard and soft contributions as
well as the VMD corrections are calculated for the first time. By analytical
evaluation of the involved one-loop integrals, we find that the transition form
factors are insensitive to both the light quark masses and the shapes of
distribution amplitudes. With the normalized transition form
factors, our results of the branching ratios
and their ratio
are in good
agreement with their experimental data. Furthermore, by the ratio
, we extract the mixing angle of system
and comment on this result briefly. Inputting
the mixing angle extracted from , we predict the
branching ratios
,
and their ratio .Comment: 14 pages, 9 figures and 5 table
Wannier-type photonic higher-order topological corner states induced solely by gain and loss
Photonic crystals have provided a controllable platform to examine excitingly
new topological states in open systems. In this work, we reveal photonic
topological corner states in a photonic graphene with mirror-symmetrically
patterned gain and loss. Such a nontrivial Wannier-type higher-order
topological phase is achieved through solely tuning on-site gain/loss
strengths, which leads to annihilation of the two valley Dirac cones at a
time-reversal-symmetric point, as the gain and loss change the effective
tunneling between adjacent sites. We find that the symmetry-protected photonic
corner modes exhibit purely imaginary energies and the role of the Wannier
center as the topological invariant is illustrated. For experimental
considerations, we also examine the topological interface states near a domain
wall. Our work introduces an interesting platform for non-Hermiticity-induced
photonic higher-order topological insulators, which, with current experimental
technologies, can be readily accessed.Comment: 7 pages, 5 figure
Liquid Metal as Connecting or Functional Recovery Channel for the Transected Sciatic Nerve
In this article, the liquid metal GaInSn alloy (67% Ga, 20.5% In, and 12.5%
Sn by volume) is proposed for the first time to repair the peripheral
neurotmesis as connecting or functional recovery channel. Such material owns a
group of unique merits in many aspects, such as favorable fluidity, super
compliance, high electrical conductivity, which are rather beneficial for
conducting the excited signal of nerve during the regeneration process in vivo.
It was found that the measured electroneurographic signal from the transected
bullfrog sciatic nerve reconnected by the liquid metal after the electrical
stimulation was close to that from the intact sciatic nerve. The control
experiments through replacement of GaInSn with the conventionally used Riger
Solution revealed that Riger Solution could not be competitive with the liquid
metal in the performance as functional recovery channel. In addition, through
evaluation of the basic electrical property, the material GaInSn works more
suitable for the conduction of the weak electroneurographic signal as its
impedance was several orders lower than that of the well-known Riger Solution.
Further, the visibility under the plain radiograph of such material revealed
the high convenience in performing secondary surgery. This new generation nerve
connecting material is expected to be important for the functional recovery
during regeneration of the injured peripheral nerve and the optimization of
neurosurgery in the near future
A penrose inequality for graphs over Kottler space
In this work, we prove an optimal Penrose inequality for asymptotically
locally hyperbolic manifolds which can be realized as graphs over Kottler
space. Such inequality relies heavily on an optimal weighted Alexandrov-Fenchel
inequality for the mean convex star shaped hypersurfaces in Kottler space
Radiative decays of bottomonia into charmonia and light mesons
In the framework of nonrelativistic QCD, we study the radiative decays of
bottomonia into charmonia, including ,
, , and . We give predictions for their branching ratios with numerical
calculations. E.g., we predict the branching ratio for
is about . As a phenomenological model study, we further
extend our calculation to the radiative decays of bottomonia into light mesons
by assuming the , and other light mesons to be
described by nonrelativistic bound states with constituent
quark masses. The calculated branching ratios for
and are roughly consistent with the CLEO data.
Comparisons with radiative decays of charmonium into light mesons such as
are also given. In all calculations the QED
contributions are taken into account and found to be significant in some
processes
Spectral operators of matrices: semismoothness and characterizations of the generalized Jacobian
Spectral operators of matrices proposed recently in [C. Ding, D.F. Sun, J.
Sun, and K.C. Toh, Math. Program. {\bf 168}, 509--531 (2018)] are a class of
matrix valued functions, which map matrices to matrices by applying a
vector-to-vector function to all eigenvalues/singular values of the underlying
matrices. Spectral operators play a crucial role in the study of various
applications involving matrices such as matrix optimization problems (MOPs)
{that include semidefinite programming as one of the most important example
classes}. In this paper, we will study more fundamental first- and second-order
properties of spectral operators, including the Lipschitz continuity,
-order B(ouligand)-differentiability (), -order
G-semismoothness (), and characterization of generalized
Jacobians.Comment: 25 pages. arXiv admin note: substantial text overlap with
arXiv:1401.226
Graphic Method for Arbitrary -body Phase Space
In quantum field theory, the phase space integration is an essential part in
all theoretical calculations of cross sections and decay widths. It is also
needed for computing the imaginary part of a physical amplitude. A key problem
is to get the phase space formula expressed in terms of any chosen invariant
masses in an -body system. We propose a graphic method to quickly get the
phase space formula of any given invariant masses intuitively for an arbitrary
-body system in general -dimensional spacetime, with the involved momenta
in any reference frame. The method also greatly simplifies the phase space
calculation just as what Feynman diagrams do in calculating scattering
amplitudes.Comment: More explanations, generalization to the general spacetime dimensions
include
- …