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PU-Flow: a Point Cloud Upsampling Network with Normalizing Flows

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arXiv 2021年

作者： Mao, Aihua Du, Zihui Hou, Junhui Duan, Yaqi Liu, Yong-Jin He, Ying School of Computer Science and Engineering South China University of Technology Guangzhou China The Department of Computer Science City University of Hong Kong Hong Kong BNRist MOE-Key Laboratory of Pervasive Computing Department of Computer Science and Technology Tsinghua University Beijing China School of Computer Science and Engineering Nanyang Technological University Singapore

Point cloud upsampling aims to generate dense point clouds from given sparse ones, which is a challenging task due to the irregular and unordered nature of point sets. To address this issue, we present a novel deep learning-based model, called PU-Flow, which incorporates normalizing flows and weight prediction techniques to produce dense points uniformly distributed on the underlying surface. Specifically, we exploit the invertible characteristics of normalizing flows to transform points between Euclidean and latent spaces and formulate the upsampling process as ensemble of neighbouring points in a latent space, where the ensemble weights are adaptively learned from local geometric context. Extensive experiments show that our method is competitive and, in most test cases, it outperforms state-of-the-art methods in terms of reconstruction quality, proximity-to-surface accuracy, and computation efficiency. The source code will be publicly available at https://***/unknownue/pu-flow. Copyright © 2021, The Authors. All rights reserved.

关键词： Signal sampling

Quark Transverse Spin-Momentum Correlation of the Pion from Lattice QCD: The Boer-Mulders Function

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arXiv 2024年

作者： Walter, Lisa Hua, Jun Lahrtz, Sebastian Ma, Lingquan Schäfer, Andreas Shu, Hai-Tao Su, Yushan Sun, Peng Wang, Wei Xiong, Xiaonu Yang, Yi-Bo Zhang, Jian-Hui Zhang, Qi-An Institut für Theoretische Physik Universität Regensburg RegensburgD-93040 Germany Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangzhou510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangzhou510006 China Center of Advanced Quantum Studies Department of Physics Beijing Normal University Beijing100875 China Key Laboratory of Quark & Lepton Physics MOE Institute of Particle Physics Central China Normal University Wuhan430079 China Department of Physics University of Maryland College ParkMD20742 United States Institute of Modern Physics Chinese Academy of Sciences Gansu Province Lanzhou730000 China INPAC Key Laboratory for Particle Astrophysics and Cosmology MOE Shanghai Key Laboratory for Particle Physics and Cosmology School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Institute of Modern Physics Chinese Academy of Sciences Guangdong Province Huizhou516000 China School of Physics and Electronics Central South University Changsha418003 China CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing100190 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCAS Hangzhou310024 China International Centre for Theoretical Physics Asia-Pacific Hangzhou Beijing China University of Chinese Academy of Sciences School of Physical Sciences Beijing100049 China School of Science and Engineering The Chinese University of Hong Kong Shenzhen518172 China School of Physics Beihang University Beijing102206 China

We present the first lattice QCD calculation of the quark transverse spin-momentum correlation, i.e., the T-odd Boer-Mulders function, of the pion, using large-momentum effective theory (LaMET). The calculation is done at three lattice spacings a = {0.098, 0.085, 0.064} fm and pion masses ∼ 350 MeV, with pion momenta up to 1.8 GeV. The matrix elements are renormalized in a state-of-the-art scheme and extrapolated to the continuum and infinite momentum limit. We have implemented the perturbative matching up to the next-to-next-to-leading order and carried out a renormalization-group resummation. Our results provide valuable input for phenomenological analyses of the Boer-Mulders single-spin asymmetry. © 2024, CC BY.

关键词： Momentum

Tuning Ru–O Coordination for Switching Redox Centers in Acidic Oxygen Evolution Electrocatalysis

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Angewandte Chemie 2025年

作者： Yajing Mu Jinchang Fan Tianyi Gao Lina Wang Lei Zhang Xiaoxin Zou Weitao Zheng Yong-Wei Zhang Zhi Gen Yu Xiaoqiang Cui School of Materials Science and Engineering Key Laboratory of Automobile Materials of MOE Jilin University Changchun 130012 China State Key Laboratory of Inorganic Synthesis and Preparative Chemistry College of Chemistry Jilin University Changchun 130012 China Institute of High Performance Computing (IHPC) Agency for Science Technology and Research (A*STAR) 1 Fusionopolis Way #16-16 Connexis Singapore 138632 Republic of Singapore

Avoiding lattice oxygen involvement (oxygen redox) while promoting the coupling of adjacent adsorbed oxygen (metal redox) during the acidic oxygen evolution reaction (OER) is essential for gaining high activity and robust stability in RuO 2 -based catalysts but remains elusive. Here, we present a precise strategy to selectively activate the metal redox process while suppressing the undesired oxygen redox pathway by fine-tuning the Ru–O coordination number in amorphous RuO x . The optimized catalyst exhibits outstanding acidic OER performance, achieving a low overpotential of 215 mV at 10 mA cm −2 and maintaining stability for 300 h with a negligible degradation rate of 100 µV h −1 . X-ray absorption measurements and multiple operando spectra reveal that only Ru 2 –O 11 moieties can selectively activate the metal redox process, whereas Ru 2 –O 9 and Ru 2 –O 8 moieties either trigger both redox pathways or bypass them. Theoretical calculations reveal that Ru 2 –O 11 moiety reduces crystal field splitting energy at active Ru sites, disables lattice oxygen activation, and lowers the energy barrier for oxygen coupling. The strategy developed in this work offers new avenues for switching redox centers and refining OER mechanisms to enhance catalytic performance and long-term stability.

关键词： Amorphous structures Coordination number Electrocatalysis Oxygen evolution reaction Ruthenium oxides

A Tent Lévy Flying Sparrow Search Algorithm for Feature Selection: A COVID-19 Case Study

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arXiv 2022年

作者： Yang, Qinwen Gao, Yuelin Song, Yanjie School of Computer Science and Engineering North Minzu University Yinchuan750021 China School of Mathematics and Information Science North Minzu University Yinchuan750021 China Ningxia Key Laboratory of Intelligent Information and Big Data Processing Yinchuan750021 China Ningxia Province Cooperative Innovation Center of Scientific Computing and Intelligent in Formation Processing North Minzu University Yinchuan750021 China College of Systems Engineering National University of Defense Technology Changsha410073 China

The "Curse of Dimensionality" induced by the rapid development of information science, might have a negative impact when dealing with big datasets. In this paper, we propose a variant of the sparrow search algorithm (SSA), called Tent Lévy flying sparrow search algorithm (TFSSA), and use it to select the best subset of features in the packing pattern for classification purposes. SSA is a recently proposed algorithm that has not been systematically applied to feature selection problems. After verification by the CEC2020 benchmark function, TFSSA is used to select the best feature combination to maximize classification accuracy and minimize the number of selected features. The proposed TFSSA is compared with nine algorithms in the literature. Nine evaluation metrics are used to properly evaluate and compare the performance of these algorithms on twenty-one datasets from the UCI repository. Furthermore, the approach is applied to the coronavirus disease (COVID-19) dataset, yielding the best average classification accuracy and the average number of feature selections, respectively, of 93.47% and 2.1. Experimental results confirm the advantages of the proposed algorithm in improving classification accuracy and reducing the number of selected features compared to other wrapper-based algorithms. Copyright © 2022, The Authors. All rights reserved.

关键词： COVID-19

Nonperturbative determination of the Collins-Soper kernel from quasitransverse-momentum-dependent wave functions

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Physical Review D 2022年第3期106卷 034509-034509页

作者： Min-Huan Chu Zhi-Fu Deng Jun Hua Xiangdong Ji Andreas Schäfer Yushan Su Peng Sun Wei Wang Yi-Bo Yang Jun Zeng Jialu Zhang Jian-Hui Zhang Qi-An Zhang Yang Yuanqing Scientific Computing Center Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 200240 China INPAC Key Laboratory for Particle Astrophysics and Cosmology (MOE) Shanghai Key Laboratory for Particle Physics and Cosmology School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China Guangdong Provincial Key Laboratory of Nuclear Science Institute of Quantum Matter South China Normal University Guangzhou 510006 China Guangdong-Hong Kong Joint Laboratory of Quantum Matter Southern Nuclear Science Computing Center South China Normal University Guangzhou 510006 China Department of Physics University of Maryland College Park Maryland 20742 USA Center for Nuclear Femtography 1201 New York Avenue NW Washington D.C. 20005 USA Institut für Theoretische Physik Universität Regensburg D-93040 Regensburg Germany Nanjing Normal University Nanjing Jiangsu 210023 China CAS Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China School of Fundamental Physics and Mathematical Sciences Hangzhou Institute for Advanced Study UCAS Hangzhou 310024 China International Centre for Theoretical Physics Asia-Pacific Beijing/Hangzhou China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China Department of Physics Center of Advanced Quantum Studies Beijing Normal University Beijing 100875 China School of Physics Beihang University Beijing 102206 China Key Laboratory for Particle Astrophysics and Cosmology (MOE) Shanghai Key Laboratory for Particle Physics and Cosmology Tsung-Dao Lee Institute Shanghai Jiao Tong University Shanghai 200240 China

In the framework of large-momentum effective theory at one-loop matching accuracy, we perform a lattice calculation of the Collins-Soper kernel, which governs the rapidity evolution of transverse-momentum-dependent (TMD) distributions. We first obtain the quasi-TMD wave functions at three different meson momenta, on a lattice with valence clover quarks on a dynamical highly improved staggered quark sea and lattice spacing a=0.12 fm from the MILC Collaboration, and renormalize the pertinent linear divergences using Wilson loops. Through one-loop matching to the light-cone wave functions, we determine the Collins-Soper kernel with transverse separation up to 0.6 fm. We study the systematic uncertainties from operator mixing and scale dependence, as well as the impact from higher power corrections. Our results potentially allow for a determination of the soft function and other transverse-momentum-dependent quantities at one-loop accuracy.

关键词： Lattice QCD

High-order finite element methods for interface problems: Theory and implementations 12th

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High-order finite element methods for interface problems: Th...

12th International Conference on Spectral and High-Order Methods, ICOSAHOM 2018

作者： Xiao, Yuanming Zhai, Fangman Zhang, Linbo Zheng, Weiying Department of Mathematics Nanjing University Nanjing China Department of Applied Mathematics Nanjing Forestry University Nanjing China State Key Laboratory of Scientific and Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China School of Mathematical Sciences University of Chinese Academy of Sciences Beijing China

ISBN: (纸本)9783030396466

We propose arbitrary order extended finite element (XFE) methods for solving both two and three dimensional elliptic interface problems. The meshes in our methods do not need to fit the interface and discontinuous Galerkin (DG) schemes are used in the vicinity of the interface to incorporate the transmission conditions between subdomains. Optimal error estimates in the piecewise H1-norm and in the L2-norm are rigorously proved for the scheme. Two implementation aspects are addressed in this paper: (1) An optimal multigrid solver is introduced for the generated linear system, which converges uniformly with respect to the mesh size. (2) A high order algorithm is presented to compute the integral over elements intersecting the interface. Numerical experiments are reported to support the theoretical results. © 2020, The Author(s).

关键词： Linear systems

Factoring integers with sublinear resources on a superconducting quantum processor

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arXiv 2022年

作者： Yan, Bao Tan, Ziqi Wei, Shijie Jiang, Haocong Wang, Weilong Wang, Hong Luo, Lan Duan, Qianheng Liu, Yiting Shi, Wenhao Fei, Yangyang Meng, Xiangdong Han, Yu Shan, Zheng Chen, Jiachen Zhu, Xuhao Zhang, Chuanyu Jin, Feitong Li, Hekang Song, Chao Wang, Zhen Ma, Zhi Wang, H. Long, Gui-Lu State Key Laboratory of Mathematical Engineering and Advanced Computing Zhengzhou450001 China State Key Laboratory of Low-Dimensional Quantum Physics Department of Physics Tsinghua University Beijing100084 China School of Physics ZJU-Hangzhou Global Scientific and Technological Innovation Center Interdisciplinary Center for Quantum Information Zhejiang Province Key Laboratory of Quantum Technology and Device Zhejiang University Hangzhou310000 China Beijing Academy of Quantum Information Sciences Beijing100193 China Institute of Information Technology Information Engineering University Zhengzhou450001 China Beijing National Research Center for Information Science and Technology School of Information Tsinghua University Beijing100084 China Frontier Science Center for Quantum Information Beijing100084 China

Shor’s algorithm has seriously challenged information security based on public key cryptosystems. However, to break the widely used RSA-2048 scheme, one needs millions of physical qubits, which is far beyond current technical capabilities. Here, we report a universal quantum algorithm for integer factorization by combining the classical lattice reduction with a quantum approximate optimization algorithm (QAOA). The number of qubits required is O(logN/loglogN), which is sublinear in the bit length of the integer N, making it the most qubit-saving factorization algorithm to date. We demonstrate the algorithm experimentally by factoring integers up to 48 bits with 10 superconducting qubits, the largest integer factored on a quantum device. We estimate that a quantum circuit with 372 physical qubits and a depth of thousands is necessary to challenge RSA-2048 using our algorithm. Our study shows great promise in expediting the application of current noisy quantum computers, and paves the way to factor large integers of realistic cryptographic significance. © 2022, CC BY-NC-ND.

关键词： Qubits

Uniqueness and uniform structural stability of poiseuille flows in a periodic pipe with Navier boundary conditions

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arXiv 2021年

作者： Wang, Yun Xie, Chunjing School of Mathematical Sciences Center for Dynamical Systems and Differential Equations Soochow University Suzhou China School of Mathematical Sciences Institute of Natural Sciences Ministry of Education Key Laboratory of Scientific and Engineering Computing Shanghai Jiao Tong University 800 Dongchuan Road Shanghai China

In this paper, we prove the uniqueness and structural stability of Poiseuille flows for axisymmetric solutions of steady Navier-Stokes system supplemented with Navier boundary conditions in a periodic pipe. Moreover, the stability is uniform with respect to both the flux and the slip coefficient of Navier boundary conditions. It is also showed that the non-zero frequency part of the velocity is bounded by a power function of the flux with negative power as long as the flux is suitably large. One of the key ingredients of the analysis is to prove the uniform linear structural stability, where the analysis for the boundary layers and the swirl velocity corresponding to the flux and the slip coefficients in different regimes plays a crucial role. Copyright © 2021, The Authors. All rights reserved.

关键词： Navier Stokes equations

Cramér-rao bound optimization for joint radar-communication design

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arXiv 2021年

作者： Liu, Fan Liu, Ya-Feng Li, Ang Masouros, Christos Eldar, Yonina C. The Department of Electrical and Electronic Engineering Southern University of Science and Technology Shenzhen518055 China The State Key Laboratory of Scientific and Engineering Computing Institute of Computational Mathematicsand Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing100190 China The School of Information and Communications Engineering Faculty of Electronic and Information Engineering Xi’an Jiaotong University Xi’anShaanxi710049 China The Department of Electronic and Electrical Engineering University College London LondonWC1E 7JE United Kingdom The Faculty of Mathematics and Computer Science Weizmann Institute of Science Rehovot Israel

In this paper, we propose multi-input multi-output (MIMO) beamforming designs towards joint radar sensing and multi-user communications. We employ the Cramér-Rao bound (CRB) as a performance metric of target estimation, under both point and extended target scenarios. We then propose minimizing the CRB of radar sensing while guaranteeing a pre-defined level of signal-to-interference-plus-noise ratio (SINR) for each communication user. For the single-user scenario, we derive a closed form for the optimal solution for both cases of point and extended targets. For the multi-user scenario, we show that both problems can be relaxed into semidefinite programming by using the semidefinite relaxation approach, and prove that the global optimum can always be obtained. Finally, we demonstrate numerically that the globally optimal solutions are reachable via the proposed methods, which provide significant gains in target estimation performance over state-of-the-art benchmarks. Copyright © 2021, The Authors. All rights reserved.

关键词： Signal to noise ratio