1,674 research outputs found

    Efficient Multi-level Correlating for Visual Tracking

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    Correlation filter (CF) based tracking algorithms have demonstrated favorable performance recently. Nevertheless, the top performance trackers always employ complicated optimization methods which constraint their real-time applications. How to accelerate the tracking speed while retaining the tracking accuracy is a significant issue. In this paper, we propose a multi-level CF-based tracking approach named MLCFT which further explores the potential capacity of CF with two-stage detection: primal detection and oriented re-detection. The cascaded detection scheme is simple but competent to prevent model drift and accelerate the speed. An effective fusion method based on relative entropy is introduced to combine the complementary features extracted from deep and shallow layers of convolutional neural networks (CNN). Moreover, a novel online model update strategy is utilized in our tracker, which enhances the tracking performance further. Experimental results demonstrate that our proposed approach outperforms the most state-of-the-art trackers while tracking at speed of exceeded 16 frames per second on challenging benchmarks.Comment: Accepted by ACCV'201

    Supercooling-enabled giant and tunable thermal rectification ratio of a phase change thermal diode

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    Phase change thermal diodes (PCTD) suffer from fairly low thermal rectification ratio, which hampers their widespread utilization as thermal management and control units for cutting-edge technologies, encompassing photovoltaics, thermoelectric modules, batteries and other miniaturized electronic products, etc. It is thus indispensable to explore a high-performance PCTD. Herein, a tunable and scalable PCTD is modeled, theoretically analyzed, fabricated and experimentally executed, accessing an unprecedented giant thermal rectification ratio of 3.0 at ambient temperature. With optimized length ratio and feasible assembly of two phase change terminals, the emerging physical states of thermal media continuously contribute to align the convective-intensified thermal conductive profiles, mandatory for heat flux manipulation within temperature bias of 10~40 {\deg}C. The most significant finding discloses the fact that supercooling elongates the overall workable temperature bias range, while manual supercooling release allows to tune the thermal rectification ratio at any temperature bias within 10~33 {\deg}C. Integrating the conventional asymmetric thermal transport mechanism with state-specific heat transfer hysteresis helps establish the novel governing mechanism

    Kazhdan-Lusztig coefficients for the lowest two-sided cell of type G2~\tilde{G_{2}}

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    This paper studies the Kazhdan-Lusztig coefficients μ(u,w)\mu(u,w) of the Kazhdan-Lusztig polynomials Pu,wP_{u,w} for the lowest cell c0{c_{0}} of an affine Weyl group of type G2~\widetilde{G_{2}} and gives an estimation μ(u,w)⩽3\mu(u,w)\leqslant 3 for u,w∈c0u,w\in c_{0}.Comment: 96 page

    Learning Cascaded Siamese Networks for High Performance Visual Tracking

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    Visual tracking is one of the most challenging computer vision problems. In order to achieve high performance visual tracking in various negative scenarios, a novel cascaded Siamese network is proposed and developed based on two different deep learning networks: a matching subnetwork and a classification subnetwork. The matching subnetwork is a fully convolutional Siamese network. According to the similarity score between the exemplar image and the candidate image, it aims to search possible object positions and crop scaled candidate patches. The classification subnetwork is designed to further evaluate the cropped candidate patches and determine the optimal tracking results based on the classification score. The matching subnetwork is trained offline and fixed online, while the classification subnetwork performs stochastic gradient descent online to learn more target-specific information. To improve the tracking performance further, an effective classification subnetwork update method based on both similarity and classification scores is utilized for updating the classification subnetwork. Extensive experimental results demonstrate that our proposed approach achieves state-of-the-art performance in recent benchmarks.Comment: Accepted for IEEE 26th International Conference on Image Processing (ICIP 2019

    Precision study on ZZγZZ\gamma production including ZZ-boson leptonic decays at the ILC

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    We report on the precision predictions for the e+e−→ZZγe^+e^-\to ZZ\gamma process including ZZ-boson leptonic decays at the ILC in the standard model (SM). The calculation includes the full next-to-leading (NLO) electroweak (EW) corrections and high order initial state radiation (h.o.ISR) contributions. We find that the NLO EW corrections heavily suppress the LO cross section, and the h.o.ISR effects are notable near the threshold while become small in high energy region. We present the LO and the NLO EW+h.o.ISR corrected distributions of the transverse momenta of final ZZ-boson and photon as well as the ZZ-pair invariant mass, and investigate the corresponding NLO EW and h.o.ISR relative corrections. We also study the leptonic decays of the final ZZ-boson pair by adopting the {\sc MadSpin} method where the spin correlation effect is involved. We conclude that both the h.o.ISR effects and the NLO EW corrections are important in exploring the ZZγZZ\gamma production at the ILC.Comment: 8 pages, 13 figures. To match the published version in Eur.Phys.J. C76 (2016) 2, 7

    Experimental test of Heisenberg's measurement uncertainty relation based on statistical distances

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    Incompatible observables can be approximated by compatible observables in joint measurement or measured sequentially, with constrained accuracy as implied by Heisenberg's original formulation of the uncertainty principle. Recently, Busch, Lahti, and Werner proposed inaccuracy trade-off relations based on statistical distances between probability distributions of measurement outcomes [Phys. Rev. Lett. 111, 160405 (2013); Phys. Rev. A 89, 012129 (2014)]. Here we reform their theoretical framework, derive an improved relation for qubit measurement, and perform an experimental test on a spin system. The relation reveals that the worst-case inaccuracy is tightly bounded from below by the incompatibility of target observables, and is verified by the experiment employing joint measurement in which two compatible but typically non-commutative observables on one qubit are measured simultaneously

    WWZ/γWWZ/\gamma production in large extra dimensions model at LHC and ILC

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    We investigate the effect induced by the Kaluza-Klein (KK) graviton in the W+W−γ/ZW^+W^-\gamma/Z production in the framework of the large extra dimensions (LED) model at both the CERN Large Hadron Collider (LHC) and the International Linear Collider (ILC). The integrated cross sections and various kinematic distributions in the LED model are presented and compared with those in the standard model. The results show that the contributions from KK-graviton exchange remarkably affect the observables of the triple gauge boson (W+W−γ/ZW^+W^-\gamma/Z) production processes at both the ILC and the LHC, particularly either in the high transverse momentum region or in the central rapidity region. We also find that the relative LED discrepancy for the W+W−γ/ZW^+W^-\gamma/Z production at the LHC is generally larger than that at the ILC due to the additional LED contribution via gggg fusion subprocess and the KK-graviton exchanging resonant effect induced by the continuous large colliding energy in pppp collision. We conclude that the W+W−γW^{+}W^{-}\gamma and W+W−ZW^{+}W^{-}Z productions at the LHC could have the distinct advantage over at the ILC from the aspect of effectively exploring the LED signal in measuring W+W−γ/ZW^+W^-\gamma/Z production.Comment: 23 pages, 19 figure

    Probing the littlest Higgs model with TT parity using di-Higgs events through ZHZ_H-pair production at the LHC in NLO QCD

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    We investigate the di-Higgs events through ZHZ_H-pair production at the CERN Large Hadron Collider including the pure next-to-leading order (NLO) QCD correction and the gggg-fusion contribution in the framework of the littlest Higgs model with TT parity. We employ the diagram subtraction scheme in the QCD NLO calculations to avoid double counting and keep the convergence of the perturbative QCD description for the ZHZ_H-pair production. We investigate the dependence of the leading order and QCD corrected integrated cross sections on the renormalization/factorization scale, and find that the total QCD corrections slightly reduce the scale uncertainty in the plotted range. By considering the subsequent decays of the intermediately produced ZHZ_H bosons and adopting the exclusive four-bb-jet event selection criterion, the QCD correction provides considerable enhancement of the kinematic distributions for final decay products. We find that it is possible to select the signature of the ZHZ_H-pair production from possible standard model background by taking proper kinematic cuts.Comment: 30 pages, 14 figure

    Precision study of W−W+HW^-W^+H production including parton shower effects at the CERN Large Hadron Collider

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    The precision study of W−W+HW^-W^+H production with subsequent W±→l±νl(−)W^{\pm} \rightarrow l^{\pm} \overset{ _{(-)}}{\nu_{l}} and H→bbˉH \rightarrow b\bar{b} decays at the LHC can help us to study the Higgs gauge couplings and to search for new physics beyond the SM. In this paper, we calculate the shower-matched NLO QCD correction and the EW corrections from the qqˉq\bar{q} annihilation and photon-induced channels to the W−W+HW^-W^+H production at the 14 TeV14~ {\rm TeV} LHC, and deal with the subsequent decays of Higgs and W±W^{\pm} bosons by adopting the {\sc MadSpin} method. Both the integrated cross section and some kinematic distributions of W±W^{\pm}, HH and their decay products are provided. We find that the QCD correction enhances the LO differential cross section significantly, while the EW correction from the qqˉq\bar{q} annihilation channel obviously suppresses the LO differential cross section, especially in the high energy phase-space region due to the Sudakov effect. The qγq\gamma- and γγ\gamma\gamma-induced relative corrections are positive, and insensitive to the transverse momenta of W±W^{\pm}, HH and their decay products. These photon-induced corrections compensate the negative qqˉq\bar{q}-initiated EW correction, and become the dominant EW contribution as the increment of the pppp colliding energy. The parton shower (PS) effects on the kinematic distributions are nonnegligible. The PS relative correction to the bb-jet transverse momentum distribution can exceed 100%100\% in the high pT,bp_{T, b} region. We also investigate the scale and PDF uncertainties, and find that the theoretical error of the QCD+EW+qγ+γγ{\rm QCD}+{\rm EW}+q\gamma+\gamma\gamma corrected integrated cross section mainly comes from the renormalization scale dependence of the QCD correction.Comment: 31 pages, 13 figures, to be published in Chinese Physics

    A Complementary Tracking Model with Multiple Features

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    Discriminative Correlation Filters based tracking algorithms exploiting conventional handcrafted features have achieved impressive results both in terms of accuracy and robustness. Template handcrafted features have shown excellent performance, but they perform poorly when the appearance of target changes rapidly such as fast motions and fast deformations. In contrast, statistical handcrafted features are insensitive to fast states changes, but they yield inferior performance in the scenarios of illumination variations and background clutters. In this work, to achieve an efficient tracking performance, we propose a novel visual tracking algorithm, named MFCMT, based on a complementary ensemble model with multiple features, including Histogram of Oriented Gradients (HOGs), Color Names (CNs) and Color Histograms (CHs). Additionally, to improve tracking results and prevent targets drift, we introduce an effective fusion method by exploiting relative entropy to coalesce all basic response maps and get an optimal response. Furthermore, we suggest a simple but efficient update strategy to boost tracking performance. Comprehensive evaluations are conducted on two tracking benchmarks demonstrate and the experimental results demonstrate that our method is competitive with numerous state-of-the-art trackers. Our tracker achieves impressive performance with faster speed on these benchmarks.Comment: Accepted by IVPAI 201
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