17,859 research outputs found
Eigenvectors of Z-tensors associated with least H-eigenvalue with application to hypergraphs
Unlike an irreducible -matrices, a weakly irreducible -tensor
can have more than one eigenvector associated with the least
H-eigenvalue. We show that there are finitely many eigenvectors of
associated with the least H-eigenvalue. If is
further combinatorial symmetric, the number of such eigenvectors can be
obtained explicitly by the Smith normal form of the incidence matrix of
. When applying to a connected uniform hypergraph , we prove
that the number of Laplacian eigenvectors of associated with the zero
eigenvalue is equal to the the number of adjacency eigenvectors of
associated with the spectral radius, which is also equal to the number of
signless Laplacian eigenvectors of associated with the zero eigenvalue if
zero is an signless Laplacian eigenvalue
A Combinatorial Method for Computing Characteristic Polynomials of Starlike Hypergraphs
By using the Poisson formula for resultants and the variants of chip-firing
game on graphs, we provide a combinatorial method for computing a class of of
resultants, i.e. the characteristic polynomials of the adjacency tensors of
starlike hypergraphs including hyperpaths and hyperstars,which are given
recursively and explicitly
Normal heat conduction in lattice models with asymmetry harmonic interparticle interactions
We study the thermal conduction behaviors of one-dimensional lattice models
with asymmetry harmonic interparticle interactions in this paper. Normal
thermal conductivity independent of the system size is observed when the
lattice chains are long enough. Because only the harmonic interactions are
involved, the result confirms without ambiguous interpretation that the
asymmetry plays key role in resulting in the normal thermal conduction in
one-dimensional momentum conserving lattices. Both equilibrium and
nonequilibrium simulations are performed to support the conclusion.Comment: 4 pages,3 figure
Review of Smart Meter Data Analytics: Applications, Methodologies, and Challenges
The widespread popularity of smart meters enables an immense amount of
fine-grained electricity consumption data to be collected. Meanwhile, the
deregulation of the power industry, particularly on the delivery side, has
continuously been moving forward worldwide. How to employ massive smart meter
data to promote and enhance the efficiency and sustainability of the power grid
is a pressing issue. To date, substantial works have been conducted on smart
meter data analytics. To provide a comprehensive overview of the current
research and to identify challenges for future research, this paper conducts an
application-oriented review of smart meter data analytics. Following the three
stages of analytics, namely, descriptive, predictive and prescriptive
analytics, we identify the key application areas as load analysis, load
forecasting, and load management. We also review the techniques and
methodologies adopted or developed to address each application. In addition, we
also discuss some research trends, such as big data issues, novel machine
learning technologies, new business models, the transition of energy systems,
and data privacy and security.Comment: IEEE Transactions on Smart Grid, 201
BBU effect in an ERL-FEL two-purpose test facility
Both the Energy Recovery Linac (ERL) and Free Electron laser (FEL) are
considered to be candidates of the fourth generation light source. It is
proposed to combine FEL into an ERL facility to integrate the advantages of
both ERL and FEL, and to realize a compact two-purpose light source. A test
facility to verify this principle is being designed at the Institute of High
Energy Physics, Beijing. One main concern is the beam breakup (BBU) instability
which limits the available beam current. To this end, we developed a numerical
simulation code to calculate the BBU threshold, which is found to have only a
small reduction even in a high-FEL-bunch-charge operation mode, compared with
that in the case with ERL bunches only. However, even with ERL beam current far
below BBU threshold, we observed a fluctuation of the central orbit of the ERL
bunches in the presence of FEL beam. We then present a physical model of BBU
and understand the mechanism of the orbit-fluctuation in an ERL-FEL two-purpose
machine. We found that by choosing an appropriate FEL bunch repetition rate,
the central orbit fluctuation amplitude can be well controlled.Comment: 10 pages, 9 figure
The Production of and in decays
Considering and as and , we
study the productions of and in exclusive weak decays of
meson by the improved Bethe-Salpeter(B-S) Method. Using the relativistic
B-S equation and Mandelstam formalism, we calculate the corresponding decay
form factors. The predictions of the corresponding branching ratios are:
and . That will provide us a new way to observe
the and in the future, as well as to improve the knowledge
of meson decay.Comment: 15 pages, 7 figure
High speed error correction for continuous-variable quantum key distribution with multi-edge type LDPC code
Error correction is a significant step in postprocessing of
continuous-variable quantum key distribution system, which is used to make two
distant legitimate parties share identical corrected keys. We propose an
experiment demonstration of high speed error correction with multi-edge type
low-density parity check (MET-LDPC) codes based on graphic processing unit
(GPU). GPU supports to calculate the messages of MET-LDPC codes simultaneously
and decode multiple codewords in parallel. We optimize the memory structure of
parity check matrix and the belief propagation decoding algorithm to reduce
computational complexity. Our results show that GPU-based decoding algorithm
greatly improves the error correction speed. For the three typical code rate,
i.e., 0.1, 0.05 and 0.02, when the block length is and the iteration
number are 100, 150 and 200, the average error correction speed can be
respectively achieved to 30.39Mbits/s (over three times faster than previous
demonstrations), 21.23Mbits/s and 16.41Mbits/s with 64 codewords decoding in
parallel, which supports high-speed real-time continuous-variable quantum key
distribution system.Comment: 8 pages, 2 figure
The weak decay to and by Bethe-Salpeter method
Considering and as and
states, the semileptonic and nonleptonic of decays to and
are studied by the improved Bethe-Salpeter(B-S) Method. The form
factors of decay are calculated through the overlap integrals of the meson wave
functions in the whole accessible kinematical range. The influence of
relativistic corrections are considered in the exclusive decays. Branching
ratios of weak decays to and are predicted. Some of
the branching ratios are: and . These results may
provide useful information to discover and and the
necessary information for the phenomenological study of physics.Comment: arXiv admin note: substantial text overlap with arXiv:1605.0909
Tur\'an's problem and Ramsey numbers for trees
Let and be the trees on vertices with
,
, and
. In this
paper, for we obtain explicit formulas for \ex(p;T_n^1) and
\ex(p;T_n^2), where \ex(p;L) denotes the maximal number of edges in a graph
of order not containing as a subgraph. Let r(G\sb 1, G\sb 2) be the
Ramsey number of the two graphs and . In this paper we also obtain
some explicit formulas for , where and is a
tree on vertices with .Comment: 21 page
Full Large-Scale Diversity Space Codes for MIMO Optical Wireless Communications
In this paper, we consider a multiple-input-multiple-output optical wireless
communication (MIMO-OWC) system suffering from log-normal fading. In this
scenario, a general criterion for the design of full large-scale diversity
space code (FLDSC) with the maximum likelihood (ML) detector is developed.
Based on our criterion, FLDSC is attained if and only if all the entries of the
space coding matrix are positive. Particularly for MIMO-OWC with
unipolar pulse amplitude modulation (PAM), a closed-form linear FLDSC
satisfying this criterion is attained by smartly taking advantage of some
available properties as well as by developing some new interesting properties
on Farey sequences in number theory to rigorously attack the continuous and
discrete variables mixed max-min problem. In fact, this specific design not
only proves that a repetition code (RC) is the best linear FLDSC, but also
uncovers a significant difference between MIMO radio frequency (RF)
communications and MIMO-OWC that space-only transmission is sufficient for a
full diversity achievement. Computer simulations demonstrate that FLDSC
substantially outperforms spatial multiplexing with the same total optical
power and spectral efficiency and the latter obtains only the small-scale
diversity gain.Comment: accepted by ISIT 201
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