108,534 research outputs found
Fraunhofer diffraction at the two-dimensional quadratically distorted (QD) Grating
A two-dimensional (2D) mathematical model of quadratically distorted (QD)
grating is established with the principles of Fraunhofer diffraction and
Fourier optics. Discrete sampling and bisection algorithm are applied for
finding numerical solution of the diffraction pattern of QD grating. This 2D
mathematical model allows the precise design of QD grating and improves the
optical performance of simultaneous multiplane imaging system.Comment: 4 pages, 6 figure
Inequalities of Hermite-Hadamard type for extended -convex functions and applications to means
In the paper, the authors introduce a new concept "extended -convex
functions", establish some new integral inequalities of Hermite-Hadamard type
for this kind of functions, and apply these inequalities to derive some
inequalities of special means.Comment: 17 page
Gradient Estimate on the Neumann Semigroup and Applications
We prove the following sharp upper bound for the gradient of the Neumann
semigroup on a -dimensional compact domain \OO with boundary either
-smooth or convex:
\|\nn P_t\|_{1\to \infty}\le \ff{c}{t^{(d+1)/2}},\ \ t>0, where is
a constant depending on the domain and is the operator
norm from L^1(\OO) to L^\infty(\OO). This estimate implies a Gaussian type
point-wise upper bound for the gradient of the Neumann heat kernel, which is
applied to the study of the Hardy spaces, Riesz transforms, and regularity of
solutions to the inhomogeneous Neumann problem on compact convex domains
Half-arc-transitive graphs of prime-cube order of small valencies
A graph is called {\em half-arc-transitive} if its full automorphism group
acts transitively on vertices and edges, but not on arcs. It is well known that
for any prime there is no tetravalent half-arc-transitive graph of order
or . Xu~[Half-transitive graphs of prime-cube order, J. Algebraic
Combin. 1 (1992) 275-282] classified half-arc-transitive graphs of order
and valency . In this paper we classify half-arc-transitive graphs of order
and valency or . In particular, the first known infinite family of
half-arc-transitive Cayley graphs on non-metacyclic -groups is constructed.Comment: 13 page
Learning to Rank Binary Codes
Binary codes have been widely used in vision problems as a compact feature
representation to achieve both space and time advantages. Various methods have
been proposed to learn data-dependent hash functions which map a feature vector
to a binary code. However, considerable data information is inevitably lost
during the binarization step which also causes ambiguity in measuring sample
similarity using Hamming distance. Besides, the learned hash functions cannot
be changed after training, which makes them incapable of adapting to new data
outside the training data set. To address both issues, in this paper we propose
a flexible bitwise weight learning framework based on the binary codes obtained
by state-of-the-art hashing methods, and incorporate the learned weights into
the weighted Hamming distance computation. We then formulate the proposed
framework as a ranking problem and leverage the Ranking SVM model to offline
tackle the weight learning. The framework is further extended to an online mode
which updates the weights at each time new data comes, thereby making it
scalable to large and dynamic data sets. Extensive experimental results
demonstrate significant performance gains of using binary codes with bitwise
weighting in image retrieval tasks. It is appealing that the online weight
learning leads to comparable accuracy with its offline counterpart, which thus
makes our approach practical for realistic applications
Improved Analytical Delay Models for RC-Coupled Interconnects
As the process technologies scale into deep submicron region, crosstalk delay
is becoming increasingly severe, especially for global on-chip buses. To cope
with this problem, accurate delay models of coupled interconnects are needed.
In particular, delay models based on analytical approaches are desirable,
because they not only are largely transparent to technology, but also
explicitly establish the connections between delays of coupled interconnects
and transition patterns, thereby enabling crosstalk alleviating techniques such
as crosstalk avoidance codes (CACs). Unfortunately, existing analytical delay
models, such as the widely cited model in [1], have limited accuracy and do not
account for loading capacitance. In this paper, we propose analytical delay
models for coupled interconnects that address these disadvantages. By
accounting for more wires and eschewing the Elmore delay, our delay models
achieve better accuracy than the model in [1].Comment: 10 pages, 2 figure
On the minimal affinizations over the quantum affine algebras of type
In this paper, we study the minimal affinizations over the quantum affine
algebras of type by using the theory of cluster algebras. We show that
the -characters of a large family of minimal affinizations of type
satisfy some systems of equations. These equations correspond to mutation
equations of some cluster algebras. Furthermore, we show that the minimal
affinizations in these equations correspond to cluster variables in these
cluster algebras.Comment: arXiv admin note: substantial text overlap with arXiv:1501.00146,
arXiv:1502.0242
A new example of limit variety of aperiodic monoids
A limit variety is a variety that is minimal with respect to being
non-finitely based. The two limit varieties of Marcel Jackson are the only
known examples of limit varieties of aperiodic monoids. Our previous work had
shown that there exists a limit subvariety of aperiodic monoids that is
different from Marcel Jackson's limit varieties. In this paper, we introduce a
new limit variety of aperiodic monoids.Comment: 16 pages, 1 figur
Rapid heating and cooling in two-dimensional Yukawa systems
Simulations are reported to investigate solid superheating and liquid
supercooling of two-dimensional (2D) systems with a Yukawa interparticle
potential. Motivated by experiments where a dusty plasma is heated and then
cooled suddenly, we track particle motion using a simulation with Langevin
dynamics. Hysteresis is observed when the temperature is varied rapidly in a
heating and cooling cycle. As in the experiment, transient solid superheating,
but not liquid supercooling, is observed. Solid superheating, which is
characterized by solid structure above the melting point, is found to be
promoted by a higher rate of temperature increase.Comment: 7 pages, 5 figure
Effect of interaction strength on the evolution of cooperation
Cooperative behaviors are ubiquitous in nature,which is a puzzle to
evolutionary biology,because the defector always gains more benefit than the
cooperator,thus,the cooperator should decrease and vanish over time.This
typical "prisoners' dilemma" phenomenon has been widely researched in recent
years.The interaction strength between cooperators and defectors is introduced
in this paper(in human society,it can be understood as the tolerance of
cooperators).We find that only when the maximum interaction strength is between
two critical values,the cooperator and defector can coexist,otherwise, 1) if it
is greater than the upper value,the cooperator will vanish, 2) if it is less
than the lower value,a bistable state will appear
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