13,405 research outputs found

    Medical Image Segmentation Based on Multi-Modal Convolutional Neural Network: Study on Image Fusion Schemes

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    Image analysis using more than one modality (i.e. multi-modal) has been increasingly applied in the field of biomedical imaging. One of the challenges in performing the multimodal analysis is that there exist multiple schemes for fusing the information from different modalities, where such schemes are application-dependent and lack a unified framework to guide their designs. In this work we firstly propose a conceptual architecture for the image fusion schemes in supervised biomedical image analysis: fusing at the feature level, fusing at the classifier level, and fusing at the decision-making level. Further, motivated by the recent success in applying deep learning for natural image analysis, we implement the three image fusion schemes above based on the Convolutional Neural Network (CNN) with varied structures, and combined into a single framework. The proposed image segmentation framework is capable of analyzing the multi-modality images using different fusing schemes simultaneously. The framework is applied to detect the presence of soft tissue sarcoma from the combination of Magnetic Resonance Imaging (MRI), Computed Tomography (CT) and Positron Emission Tomography (PET) images. It is found from the results that while all the fusion schemes outperform the single-modality schemes, fusing at the feature level can generally achieve the best performance in terms of both accuracy and computational cost, but also suffers from the decreased robustness in the presence of large errors in any image modalities.Comment: Zhe Guo and Xiang Li contribute equally to this wor

    O-operators on associative algebras and associative Yang–Baxter equations

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    An O-operator on an associative algebra is a generalization of a Rota–Baxter operator that plays an important role in the Hopf algebra approach of Connes and Kreimer to the renormalization of quantum field theory. It is also the associative analog of an O-operator on a Lie algebra in the study of the classical Yang–Baxter equation. We introduce the concept of an extended O-operator on an associative algebra whose Lie algebra analog has been applied to generalized Lax pairs and PostLie algebras. We study algebraic structures coming from extended O-operators. Continuing the work of Aguiar deriving Rota–Baxter operators from the associative Yang–Baxter equation, we show that its solutions correspond to extended O-operators through a duality. We also establish a relationship of extended O-operators with the generalized associative Yang–Baxter equation

    Teleporting a rotation on remote photons

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    Quamtum remote rotation allows implement local quantum operation on remote systems with shared entanglement. Here we report an experimental demonstration of remote rotation on single photons using linear optical element. And the local dephase is also teleported during the process. The scheme can be generalized to any controlled rotation commutes with σz\sigma_{z}.Comment: 5 pages, 4 figure

    Annihilation Rates of Heavy 11^{--} S-wave Quarkonia in Salpeter Method

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    The annihilation rates of vector 11^{--} charmonium and bottomonium 3S1^3S_1 states Ve+eV \rightarrow e^+e^- and V3γV\rightarrow 3\gamma, VγggV \rightarrow \gamma gg and V3gV \rightarrow 3g are estimated in the relativistic Salpeter method. We obtained Γ(J/ψ3γ)=6.8×104\Gamma(J/\psi\rightarrow 3\gamma)=6.8\times 10^{-4} keV, Γ(ψ(2S)3γ)=2.5×104\Gamma(\psi(2S)\rightarrow 3\gamma)=2.5\times 10^{-4} keV, Γ(ψ(3S)3γ)=1.7×104\Gamma(\psi(3S)\rightarrow 3\gamma)=1.7\times 10^{-4} keV, Γ(Υ(1S)3γ)=1.5×105\Gamma(\Upsilon(1S)\rightarrow 3\gamma)=1.5\times 10^{-5} keV, Γ(Υ(2S)3γ)=5.7×106\Gamma(\Upsilon(2S)\rightarrow 3\gamma)=5.7\times 10^{-6} keV, Γ(Υ(3S)3γ)=3.5×106\Gamma(\Upsilon(3S)\rightarrow 3\gamma)=3.5\times 10^{-6} keV and Γ(Υ(4S)3γ)=2.6×106\Gamma(\Upsilon(4S)\rightarrow 3\gamma)=2.6\times 10^{-6} keV. In our calculations, special attention is paid to the relativistic correction, which is important and can not be ignored for excited 2S2S, 3S3S and higher excited states.Comment: 10 pages,2 figures, 5 table

    Achieving quantum precision limit in adaptive qubit state tomography

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    The precision limit in quantum state tomography is of great interest not only to practical applications but also to foundational studies. However, little is known about this subject in the multiparameter setting even theoretically due to the subtle information tradeoff among incompatible observables. In the case of a qubit, the theoretic precision limit was determined by Hayashi as well as Gill and Massar, but attaining the precision limit in experiments has remained a challenging task. Here we report the first experiment which achieves this precision limit in adaptive quantum state tomography on optical polarization qubits. The two-step adaptive strategy employed in our experiment is very easy to implement in practice. Yet it is surprisingly powerful in optimizing most figures of merit of practical interest. Our study may have significant implications for multiparameter quantum estimation problems, such as quantum metrology. Meanwhile, it may promote our understanding about the complementarity principle and uncertainty relations from the information theoretic perspective.Comment: 9 pages, 4 figures; titles changed and structure reorganise
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