1,415 research outputs found
Path diversity improves the identification of influential spreaders
Identifying influential spreaders in complex networks is a crucial problem
which relates to wide applications. Many methods based on the global
information such as -shell and PageRank have been applied to rank spreaders.
However, most of related previous works overwhelmingly focus on the number of
paths for propagation, while whether the paths are diverse enough is usually
overlooked. Generally, the spreading ability of a node might not be strong if
its propagation depends on one or two paths while the other paths are dead
ends. In this Letter, we introduced the concept of path diversity and find that
it can largely improve the ranking accuracy. We further propose a local method
combining the information of path number and path diversity to identify
influential nodes in complex networks. This method is shown to outperform many
well-known methods in both undirected and directed networks. Moreover, the
efficiency of our method makes it possible to be applied to very large systems.Comment: 6 pages, 6 figure
Topological Excitation in Skyrme Theory
Based on the -mapping topological current theory and the decomposition
of gauge potential theory, we investigate knotted vortex lines and monopoles in
Skyrme theory and simply discuss the branch processes (splitting, merging and
intersection) during the evolution of the monopoles.Comment: 10 pages, 0 figure
Submodular Load Clustering with Robust Principal Component Analysis
Traditional load analysis is facing challenges with the new electricity usage
patterns due to demand response as well as increasing deployment of distributed
generations, including photovoltaics (PV), electric vehicles (EV), and energy
storage systems (ESS). At the transmission system, despite of irregular load
behaviors at different areas, highly aggregated load shapes still share similar
characteristics. Load clustering is to discover such intrinsic patterns and
provide useful information to other load applications, such as load forecasting
and load modeling. This paper proposes an efficient submodular load clustering
method for transmission-level load areas. Robust principal component analysis
(R-PCA) firstly decomposes the annual load profiles into low-rank components
and sparse components to extract key features. A novel submodular cluster
center selection technique is then applied to determine the optimal cluster
centers through constructed similarity graph. Following the selection results,
load areas are efficiently assigned to different clusters for further load
analysis and applications. Numerical results obtained from PJM load demonstrate
the effectiveness of the proposed approach.Comment: Accepted by 2019 IEEE PES General Meeting, Atlanta, G
Self-dual Vortices in the Abelian Chern-Simons Model with Two Complex Scalar Fields
Making use of -mapping topological current method, we discuss the
self-dual vortices in the Abelian Chern-Simons model with two complex scalar
fields. For each scalar field, an exact nontrivial equation with a topological
term which is missing in many references is derived analytically. The general
angular momentum is obtained. The magnetic flux which relates the two scalar
fields is calculated. Furthermore, we investigate the vortex evolution
processes, and find that because of the present of the vortex molecule, these
evolution processes is more complicated than the vortex evolution processes in
the corresponding single scalar field model.Comment: 9 pages, no figure
Fermions on Thick Branes in the Background of Sine-Gordon Kinks
A class of thick branes in the background of sine-Gordon kinks with a scalar
potential was constructed by R. Koley and S.
Kar [Classical Quantum Gravity \textbf{22}, 753 (2005)]. In this paper, in the
background of the warped geometry, we investigate the issue of localization of
spin half fermions on these branes in the presence of two types of
scalar-fermion couplings: and . By presenting the mass-independent potentials in the corresponding
Schr\"{o}dinger equations, we obtain the lowest Kaluza--Klein (KK) modes and a
continuous gapless spectrum of KK states with for both types of
couplings. For the Yukawa coupling , the effective
potential of the right chiral fermions for positive and is always
positive, hence only the effective potential of the left chiral fermions could
trap the corresponding zero mode. This is a well-known conclusion which had
been discussed extensively in the literature. However, for the coupling
, the effective potential of the right chiral
fermions for positive and is no longer always positive. Although the
value of the potential at the location of the brane is still positive, it has a
series of wells and barriers on each side, which ensures that the right chiral
fermion zero mode could be trapped. Thus we may draw the remarkable conclusion:
for positive and , the potentials of both the left and right chiral
fermions could trap the corresponding zero modes under certain restrictions.Comment: 22 pages, 21 figures, published version to appear in Phys. Rev.
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