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A Splitting Method for the Degasperis-Procesi Equation Using an Optimized WENO Scheme and the Fourier Pseudospectral Method

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Advances in Applied Mathematics and Mechanics 2019年第1期11卷 53-71页

作者： Yunrui Guo Wenjing Yang Hong Zhang Ji Wang Songhe Song State Key Laboratory of High Performance Computing College of ComputerNational University of Defense TechnologyChangsha 410073China Department of Mathematics Utrecht UniversityThe Netherlands P.O.Box 80.0103508TAUtrecht Department of Mathematics College of SciencesNational University of Defense TechnologyChangsha 410073China

The Degasperis-Procesi(DP)equation is split into a system of a hyperbolic equation and an elliptic *** the hyperbolic equation,we use an optimized finite difference weighted essentially non-oscillatory(OWENO)*** smoothness measurement is presented to approximate the typical shockpeakon structure in the solution to the DP equation,which evidently reduces the dissipation arising from discontinuities simultaneously removing nonphysical *** the elliptic equation,the Fourier pseudospectral method(FPM)is employed to discretize the high order *** to the combination of the WENO reconstruction and FPM,the splitting method shows an excellent performance in capturing the formation and propagation of shockpeakon *** numerical simulations for different solutions of the DP equation are conducted to illustrate the high accuracy and capability of the method.

关键词： Degasperis-Procesi equation discontinuous solution weighted essentially nonoscillatory method pseudospectral method

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Intrinsic elastic conductors with internal buckled electron pathway for flexible electromagnetic interference shielding and tumor ablation

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Science China Materials 2020年第7期63卷 1318-1329页

作者： Wenqian He Rui Zhang Yuanyuan Cheng Chao Zhang Xiang Zhou Zhuangjian Liu Xiaoyu Hu Zhongsheng Liu Jinkun Sun Yinsong Wang Dong Qian Zunfeng Liu Key Laboratory of Functional Polymer Materials College of PharmacyState Key Laboratory of Medicinal Chemical BiologyNankai UniversityTianjin 300071China Department of Mechanical Engineering University of Texas at DallasRichardsonTX 75080USA Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics(Theranostics) School of PharmacyTianjin Medical UniversityTianjin 300070China Jiangsu Key Laboratory of Bioactive Natural Product Research and State Key Laboratory of Natural Medicines China Pharmaceutical UniversityNanjing 210009China Institute of High Performance Computing A*STAR Research EntitiesSingapore 138632Singapore

The elastic conductor is crucial in wearable electronics and soft *** ideal intrinsic elastic bulk conductors show uniform three-dimensional conductive networks and stable resistance during large stretch.A challenge is that the variation of resistance is high under deformation due to disconnection of conductive pathway for bulk elastic *** strategy is to introduce buckled structure into the conductive network,by self-assembly of a carbon nanotube layer on the interconnecting micropore surface of a prestrained foam,followed by strain *** unfolding of buckles and flattening of micropores contributed to the stability of the resistance under deformation(2.0%resistance variation under 70%strain).Microstructural analysis and finite element analysis illustrated different patterns of two-dimensional buckling structures could be obtained due to the imperfections in the conductive *** as all-directional interconnects,stretchable electromagnetic interference shielding and electrothermal tumor ablation were demonstrated.

关键词： intrinsic elastic conductor buckled structure three-dimensional conductive network electromagnetic interference shielding electrothermal tumor ablation

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HL-LSM: A LSM-Tree Combined with Read Hotness and Learned Index

HL-LSM: A LSM-Tree Combined with Read Hotness and Learned In...

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IEEE International Conference on Big Data

作者： Hong Tan Hui Li Xiaopeng Wang Weixiang Huang Runhuai Huang Shaowen Deng Jianping Wu Shenzhen Graduate School Peking University Shenzhen China Guangdong Provincial Key Laboratory of Ultra High Definition Immersive Media Technology School of Computer & AI FuYao Univ. of Sci. &Tech Fuzhou China Capability & Platform Business Dept China Mobile Internet Co. Ltd Guangzhou China China Telecom Cloud Computing China Telecom Co. Ltd Beijing China China Unicom Global Limited Hong Kong China China Communications Services Construction Co. Ltd GuangZhou China

ISBN: (数字)9798350362480

ISBN: (纸本)9798350362497

Log-Structured Merge Tree (LSM-Tree) is widely employed in key-value (kv) store owing to its exceptional performance in write-intensive workloads. LSMTree appends kv pairs to memory initially, and only when the memory capacity reaches a threshold does it flush the data to disk. However, in comparison to write, read operations often entail more disk access, resulting in relatively a slower response speed. Although LSM-Tree utilizes an index structure to expedite read operations, its performance enhancement remains limited. In addition, LSM-Tree fails to consider the read hotness of each sorted string table (SSTable) during compaction, leading to significant fluctuations in performance. This paper introduces HL-LSM, a novel LSM-Tree. HL-LSM utilizes learned index to replace original index to save system overhead and improve read performance. Moreover, a lightweight read hotness statistics is devised to optimize the compaction and assess the feasibility of each SSTable in constructing a learned index. In order to evaluate the performance of HL-LSM, we constructed a system prototype, HLDB, based on Wisckey. Experiment demonstrates that in read-intensive scenarios, HLDB is able to reduce the overall system latency by nearly 10% compared to Wisckey. Furthermore, it was observed that the optimization effect of HL-LSM improves as the variance of hotness value distribution increases.

关键词： Fluctuations System performance Prototypes Big Data Compaction Indexes Optimization

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Helicity‐dependent THz emission induced by ultrafast spin photocurrent in nodal‐line semimetal candidate Mg3Bi2

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Opto-Electronic Advances 2020年第12期3卷 9-16页

作者： Mingyu Tong Yuze Hu Xiangnan Xie Xiegang Zhu Zhenyu Wang Xiang'ai Cheng Tian Jiang College of Advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 410073China National Innovation Institute of Defense Technology Academy of Military Sciences PLA ChinaBeijing 100010China State Key Laboratory of High Performance Computing College of ComputerNational University of Defense TechnologyChangsha 410073China Beijing Academy of Quantum Information Sciences Beijing 100193China Science and Technology on Surface Physics and Chemistry Laboratory Jiangyou 621908China

Helicity-dependent ultrafast spin current generated by circularly polarized photons in topological materials holds the crux to many technological improvements,such as quantum communications,on-chip communication processing and ***,we present the manipulation of helicity-dependent terahertz emission generated in a nodal line semimetal candidate Mg3Bi2 by using photon polarization *** terahertz emission is mainly ascribed to the helicity-dependent photocurrent that is originated from circular photogalvanic effects,and the helicity-independent photocurrent that is attributed to linear photogalvanic *** work will inspire more explorations into novel nodal line semimetals and open up new opportunities for developing ultrafast optoelectronics in the topological system.

关键词： terahertz spin photocurrent nodal-line semimetal topological material

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Sketch2Relief: Generating Bas-relief from Sketches with Deep Generative Networks

Sketch2Relief: Generating Bas-relief from Sketches with Deep...

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International Conference on Tools for Artificial Intelligence (ICTAI)

作者： Shizhe Zhou Zeyu Liu Key Laboratory of High Performance Computing and Stochastic Information Processing Ministry of Education of China College of Computer Science and Electronic Engineering Hunan University Changsha China

ISBN: (数字)9781728192284

ISBN: (纸本)9781728185361

We present a novel sketch-based system for generating digital bas-relief sculptures. All existing computational methods for generating digital bas-reliefs first require the input of a three-dimensional (3D) scene, thus preventing artists from freely creating or exploring designs when 3D data are not available. Motivated by this limitation, we propose a generative adversarial network (GAN)-based sketch modeling system for generating digital bas-reliefs from freehand user sketches (see Figure 1, 5). The basic tool underpinning the interface is a conditional GAN (cGAN) that digitally learns a functional map from a contour image to a 3D model for any given viewpoint of the corresponding bas-relief model. When using our system for designing bas-reliefs, the user only needs to draw 2D sketch lines without having to designate any additional hints on the lines. The interface returns bas-relief results in interactive time (500 ms per bas-relief on average). We tested the quality and robustness of our approach with extensive and comprehensive experiments. By carefully analyzing the results, we verified that our system can faithfully reconstruct bas-reliefs from a test dataset and can generate completely new reliefs from raw amateur sketches.

关键词： Solid modeling Three-dimensional displays Two dimensional displays Neural networks Tools Generative adversarial networks Robustness

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HeadCap: A Hierarchical Encoder-And-Decoder Image Captioning Model

HeadCap: A Hierarchical Encoder-And-Decoder Image Captioning...

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International Conference on Intelligent computing, Automation and Systems (ICICAS)

作者： Wenjing Yang Shiwei Wang Long Lan Institute for Quantum Information & State Key Laboratory of High Performance Computing National University of Defense Technology Changsha China Yunnan North Optical & Electronic Instrument Co. Ltd Kunming China

The following topics are dealt with: power grids; learning (artificial intelligence); power engineering computing; feature extraction; deep learning (artificial intelligence); image classification; image segmentation;... 详细信息

关键词： Bridges Visualization Automation Semantics Computer architecture Feature extraction Decoding

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Optimization of a global seventh-order dissipative compact finite-difference scheme by a genetic algorithm

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Applied Mathematics and Mechanics(English Edition) 2018年第11期39卷 1679-1690页

作者： Yu LIN Yaming CHEN Chuanfu XU Xiaogang DENG College of Computer National University of Defense Technology College of Aerospace Science and Engineering National University of Defense Technology State Key Laboratory of High Performance Computing National University of Defense Technology

A global seventh-order dissipative compact finite-difference scheme is optimized in terms of time stability. The dissipative parameters appearing in the boundary closures are assumed to be different, resulting in an optimization problem with several parameters determined by applying a generic algorithm. The optimized schemes are analyzed carefully from the aspects of the eigenvalue distribution, the ε-pseudospectra, the short time behavior, and the Fourier analysis. Numerical experiments for the Euler equations are used to show the effectiveness of the final recommended scheme.

关键词： high-order dissipative compact finite-difference scheme genetic algorithm time stable

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Chiral Phosphoric Acid Catalyzed Asymmetric Hydrolysis of Biaryl Oxazepines for the Synthesis of Axially Chiral Biaryl Amino Phenol Derivatives

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Angewandte Chemie 2023年第39期135卷

作者： Liwen Wei Jiaomeng Li Yi Zhao Qinglong Zhou Zhikang Wei Yuhang Chen Dr. Xinglong Zhang Prof. Dr. Xing Yang Key Laboratory of Chemical Biology and Traditional Chinese Medicine (Ministry of Educational of China) Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province College of Chemistry and Chemical Engineering Hunan Normal University Changsha 410081 P. R. China Institute of High Performance Computing Agency for Science Technology and Research (A*STAR) Singapore 138632 Singapore

The development of catalytic asymmetric reaction with water as the reactant is challenging due to the reactivity- and stereoselectivity-control issues resulted from the low nucleophilicity and the small size of water. We disclose herein a chiral phosphoric acid (CPA) catalyzed atroposelective ring-opening reaction of biaryl oxazepines with water. A series of biaryl oxazepines undergo the CPA catalyzed asymmetric hydrolysis in a highly enantioselective manner. The key for the success of this reaction is the use of a new SPINOL-derived CPA catalyst and the high reactivity of biaryl oxazepine substrates towards water under acidic conditions. Density functional theory calculations suggest that the reaction proceeds via a dynamic kinetic resolution pathway and the CPA catalyzed addition of water to the imine group is both enantio- and rate-determining.

关键词： Atropisomerism Bridged Biaryls Hydrolysis Organocatalysis Ring-Opening

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ECML: An Ensemble Cascade Metric Learning Mechanism towards Face Verification

arXiv

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arXiv 2020年

作者： Xiong, Fu Xiao, Yang Cao, Zhiguo Wang, Yancheng Zhou, Joey Tianyi Wu, Jianxin National Key Laboratory of Science and Technology on Multispectral Information Processing School of Artificial Intelligence and Automation Huazhong University of Science and Technology Wuhan430074 China Institute of High Performance Computing A*STAR Singapore Singapore National Key Laboratory for Novel Software Technology Nanjing University Nanjing210023 China

Face verification can be regarded as a 2-class fine-grained visual recognition problem. Enhancing the feature’s discriminative power is one of the key problems to improve its performance. Metric learning technology is often applied to address this need, while achieving a good tradeoff between underfitting and overfitting plays the vital role in metric learning. Hence, we propose a novel ensemble cascade metric learning (ECML) mechanism. In particular, hierarchical metric learning is executed in the cascade way to alleviate underfitting. Meanwhile, at each learning level, the features are split into non-overlapping groups. Then, metric learning is executed among the feature groups in the ensemble manner to resist overfitting. Considering the feature distribution characteristics of faces, a robust Mahalanobis metric learning method (RMML) with closed-form solution is additionally proposed. It can avoid the computation failure issue on inverse matrix faced by some well-known metric learning approaches (e.g., KISSME). Embedding RMML into the proposed ECML mechanism, our metric learning paradigm (EC-RMML) can run in the one-pass learning manner. Experimental results demonstrate that EC-RMML is superior to state-of-the-art metric learning methods for face verification. And, the proposed ensemble cascade metric learning mechanism is also applicable to other metric learning approaches. Copyright © 2020, The Authors. All rights reserved.

关键词： Inverse problems

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Observation of quantum oscillations near the Mott-Ioffe-Regel limit in CaAs3

arXiv

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arXiv 2024年

作者： Wang, Yuxiang Zhao, Minhao Zhang, Jinglei Wu, Wenbin Li, Shichao Zhang, Yong Jiang, Wenxiang Joseph, Nesta Benno Xu, Liangcai Mou, Yicheng Yang, Yunkun Leng, Pengliang Zhang, Yong Pi, Li Suslov, Alexey Ozerov, Mykhaylo Wyzula, Jan Orlita, Milan Zhu, Fengfeng Zhang, Yi Kou, Xufeng Zhu, Zengwei Narayan, Awadhesh Qian, Dong Wen, Jinsheng Yuan, Xiang Xiu, Faxian Zhang, Cheng State Key Laboratory of Surface Physics Institute for Nanoelectronic Devices and Quantum Computing Fudan University Shanghai200433 China State Key Laboratory of Surface Physics Department of Physics Fudan University Shanghai200433 China Shanghai Qi Zhi Institute 41st Floor AI Tower No. 701 Yunjin Road Xuhui District Shanghai200232 China Anhui Province Key Laboratory of Condensed Matter Physics at Extreme Conditions High Magnetic Field Laboratory of the Chinese Academy of Sciences Hefei230031 China State Key Laboratory of Precision Spectroscopy East China Normal University Shanghai200241 China National Laboratory of Solid State Microstructures Department of Physics Nanjing University Nanjing210093 China School of Physics and Astronomy Shanghai Jiao Tong University Shanghai200240 China Solid State and Structural Chemistry Unit Indian Institute of Science Bangalore560012 India Wuhan National High Magnetic Field Center School of Physics Huazhong University of Science and Technology Wuhan430074 China School of Information Science and Technology ShanghaiTech University Shanghai201210 China National High Magnetic Field Laboratory TallahasseeFL32310 United States LNCMI-CNRS UPR3228 Université Grenoble Alpes Université Toulouse 3 INSA Toulouse EMFL 25 rue des Martyrs BP166 Grenoble38042 Cedex 9 France International Center for Quantum Materials School of Physics Peking University Beijing100871 China School of Physics and Electronic Science East China Normal University Shanghai200241 China Zhangjiang Fudan International Innovation Center Fudan University Shanghai201210 China Shanghai Research Center for Quantum Sciences Shanghai201315 China

The Mott-Ioffe-Regel limit sets the lower bound of carrier mean free path for coherent quasiparticle transport.1,2 Metallicity beyond this limit is of great interest because it is often closely related to quantum criticality and unconventional superconductivity.3–5 Progress along this direction mainly focuses on the strange-metal behaviors originating from the evolution of quasiparticle scattering rate such as linear-in-temperature resistivity4, while the quasiparticle coherence phenomena in this regime are much less explored due to the short mean free path at the diffusive bound. Here we report the observation of quantum oscillations from Landau quantization near the Mott-Ioffe-Regel limit in CaAs3. Despite the insulator-like temperature dependence of resistivity, CaAs3 presents giant magnetoresistance and prominent Shubnikov–de Haas oscillations from Fermi surfaces, indicating highly-coherent band transport. In contrast, the quantum oscillation is absent in the magnetic torque. The quasiparticle effective mass increases systematically with magnetic fields, manifesting a much larger value than the expectation given by magneto-infrared spectroscopy. It suggests a strong many-body renormalization effect near Fermi surface. We find that these unconventional behaviors may be explained by the interplay between the mobility edge and the van Hove singularity, which results in the formation of coherent cyclotron orbits emerging at the diffusive bound. Our results call for further study on the electron correlation effect of the van Hove singularity. © 2024, CC BY.

关键词： Infrared spectroscopy

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