14,717 research outputs found
On stability of the Hamiltonian index under contractions and closures
The hamiltonian index of a graph is the smallest integer such that the -th iterated line graph of is hamiltonian. We first show that, with one exceptional case, adding an edge to a graph cannot increase its hamiltonian index. We use this result to prove that neither the contraction of an -contractible subgraph of a graph nor the closure operation performed on (if is claw-free) affects the value of the hamiltonian index of a graph
Consensus analysis of multiagent networks via aggregated and pinning approaches
This is the post-print version of of the Article - Copyright @ 2011 IEEEIn this paper, the consensus problem of multiagent nonlinear directed networks (MNDNs) is discussed in the case that a MNDN does not have a spanning tree to reach the consensus of all nodes. By using the Lie algebra theory, a linear node-and-node pinning method is proposed to achieve a consensus of a MNDN for all nonlinear functions satisfying a given set of conditions. Based on some optimal algorithms, large-size networks are aggregated to small-size ones. Then, by applying the principle minor theory to the small-size networks, a sufficient condition is given to reduce the number of controlled nodes. Finally, simulation results are given to illustrate the effectiveness of the developed criteria.This work was jointly supported by CityU under a research grant (7002355) and GRF funding (CityU 101109)
Leveraging Contextual Cues for Generating Basketball Highlights
The massive growth of sports videos has resulted in a need for automatic
generation of sports highlights that are comparable in quality to the
hand-edited highlights produced by broadcasters such as ESPN. Unlike previous
works that mostly use audio-visual cues derived from the video, we propose an
approach that additionally leverages contextual cues derived from the
environment that the game is being played in. The contextual cues provide
information about the excitement levels in the game, which can be ranked and
selected to automatically produce high-quality basketball highlights. We
introduce a new dataset of 25 NCAA games along with their play-by-play stats
and the ground-truth excitement data for each basket. We explore the
informativeness of five different cues derived from the video and from the
environment through user studies. Our experiments show that for our study
participants, the highlights produced by our system are comparable to the ones
produced by ESPN for the same games.Comment: Proceedings of ACM Multimedia 201
Primordial Lepton Family Asymmtries in Seesaw Model
In leptogenesis scenario, the decays of heavy Majorana neutrinos generate
lepton family asymmetries, and . They are sensitive to
CP violating phases in seesaw models. The time evolution of the lepton family
asymmetries are derived by solving Boltzmann equations. By taking a minimal
seesaw model, we show how each family asymmetry varies with a CP violating
phase. For instance, we find the case that the lepton asymmetry is dominated by
or depending on the choice of the CP violating phase. We
also find the case that the signs of lepton family asymmetries and
are opposite each other. Their absolute values can be larger than
the total lepton asymmetry and the baryon asymmetry may result from the
cancellation of the lepton family asymmetries.Comment: 26 pages, 8 figures, ptp.styl
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