1,872 research outputs found
Posing 3D Models from Drawing
Inferring the 3D pose of a character from a drawing is a complex and under-constrained problem. Solving it may help automate various parts of an animation production pipeline such as pre-visualisation. In this paper, a novel way of inferring the 3D pose from a monocular 2D sketch is proposed. The proposed method does not make any external assumptions about the model, allowing it to be used on different types of characters. The inference of the 3D pose is formulated as an optimisation problem and a parallel variation of the Particle Swarm Optimisation algorithm called PARAC-LOAPSO is utilised for searching the minimum. Testing in isolation as well as part of a larger scene, the presented method is evaluated by posing a lamp, a horse and a human character. The results show that this method is robust, highly scalable and is able to be extended to various types of models
Exact Algorithms for Maximum Independent Set
We show that the maximum independent set problem (MIS) on an -vertex graph
can be solved in time and polynomial space, which even is
faster than Robson's -time exponential-space algorithm
published in 1986. We also obtain improved algorithms for MIS in graphs with
maximum degree 6 and 7, which run in time of and
, respectively. Our algorithms are obtained by using fast
algorithms for MIS in low-degree graphs in a hierarchical way and making a
careful analyses on the structure of bounded-degree graphs
Experimental Quantum Teleportation and Multi-Photon Entanglement via Interfering Narrowband Photon Sources
In this letter, we report a realization of synchronization-free quantum
teleportation and narrowband three-photon entanglement through interfering
narrowband photon sources. Since both the single-photon and the entangled
photon pair utilized are completely autonomous, it removes the requirement of
high demanding synchronization technique in long-distance quantum communication
with pulsed spontaneous parametric down-conversion sources. The frequency
linewidth of the three-photon entanglement realized is on the order of several
MHz, which matches the requirement of atomic ensemble based quantum memories.
Such a narrowband multi-photon source will have applications in some advanced
quantum communication protocols and linear optical quantum computation
Fitness-driven deactivation in network evolution
Individual nodes in evolving real-world networks typically experience growth
and decay --- that is, the popularity and influence of individuals peaks and
then fades. In this paper, we study this phenomenon via an intrinsic nodal
fitness function and an intuitive aging mechanism. Each node of the network is
endowed with a fitness which represents its activity. All the nodes have two
discrete stages: active and inactive. The evolution of the network combines the
addition of new active nodes randomly connected to existing active ones and the
deactivation of old active nodes with possibility inversely proportional to
their fitnesses. We obtain a structured exponential network when the fitness
distribution of the individuals is homogeneous and a structured scale-free
network with heterogeneous fitness distributions. Furthermore, we recover two
universal scaling laws of the clustering coefficient for both cases, and , where and refer to the node degree and the
number of active individuals, respectively. These results offer a new simple
description of the growth and aging of networks where intrinsic features of
individual nodes drive their popularity, and hence degree.Comment: IoP Styl
Greenberger-Horne-Zeilinger-type violation of local realism by mixed states
Cluster states are multi-particle entangled states with special entanglement
properties particularly suitable for quantum computation. It has been shown
that cluster states can exhibit Greenberger-Horne-Zeilinger (GHZ)-type
non-locality even when some of their qubits have been lost. In the present
work, we generated a four-photon mixed state, which is equivalent to the
partial, qubit-loss state of an N-qubit cluster state up to some local
transformations. By using this mixed state, we then realize a GHZ-type
violation of local realism. Our results not only demonstrate a mixed state's
GHZ-type non-locality but also exhibit the robustness of cluster states under
qubit-loss conditions.Comment: four pages, five figures, revTe
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