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O2iJoin： An Efficient Index-Based Algorithm for Overlap Interval Join

Journal of Computer Science & technology 2018年第5期33卷 1023-1038页

作者： Ji-Zhou Luo Sheng-Fei Shi Guang Yang Hong-Zhi Wang Jian-Zhong Li School of Computer Science and Technology Harbin Institute of Technology Harbin 150001 China Guangdong Key Laboratory of Popular High Performance Computers Key Laboratory of Service Computing and Application Shenzhen 518000 China

Time intervals are often associated with tuples to represent their valid time in temporal relations, where overlap join is crucial for various kinds of queries. Many existing overlap join algorithms use indices based on tree structures such as quad-tree, B＋-tree and interval tree. These algorithms usually have high CPU cost since deep path traversals are unavoidable, which makes them not so competitive as data-partition or plane-sweep based algorithms. This paper proposes an efficient overlap join algorithm based on a new two-layer flat index named as Overlap Interval Inverted Index （i.e., O2i Index）. It uses an array to record the end points of intervals and approximates the nesting structures of intervals via two functions in the first layer, and the second layer uses inverted lists to trace all intervals satisfying the approximated nesting structures. With the help of the new index, the join algorithm only visits the must-be-scanned lists and skips all others. Analyses and experiments on both real and synthetic datasets show that the proposed algorithm is as competitive as the state-of-the-art algorithms.

关键词： overlap interval join temporal relation overlap inverted index join algorithm

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A SIMPLE RIEMANN SOLVER AND high-ORDER GODUNOV SCHEMES FOR HYPERBOLIC SYSTEMS OF CONSERVATION-LAWS

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JOURNAL OF COMPUTATIONAL PHYSICS 1995年第1期121卷 51-65页

作者： DAI, WL WOODWARD, PR School of Physics and Astronomy Supercomputer Institute Army High Performance Computing Research Center University of Minnesota 1100 Washington Avenue South Minneapolis Minnesota 55415

A simple approximate Riemann solver for hyperbolic systems of conservation laws is developed for its use in Godunov schemes. The solver is based on characteristic formulations and is illustrated through Euler and ideal magnetohydrodynamical (MHD) equations. The procedure of a high-order Godunov scheme incorporated with the Riemann solver for one-dimensional hyperbolic systems of conservation laws is described in detail. The correctness of the scheme is shown by comparison with the piecewise parabolic method for Euler equations and by comparison with exact solutions of Riemann problems for ideal MHD equations. The robustness of the scheme is demonstrated through numerical examples involving more than one strong shock at the same time. It is shown that the scheme offers the principle advantages of Godunov schemes: robust operation in the presence of strong waves, thin shock fronts, thin contact and slip surface discontinuities. (C) 1995 Academic Press, Inc.

关键词： Shock waves

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Automatic architecture design for distributed quantum computing

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Chinese Physics B 2024年第12期33卷 45-59页

作者： Ting-Yu Luo Yu-Zhen Zheng Xiang Fu Yu-Xin Deng Shanghai Key Laboratory of Trustworthy Computing East China Normal UniversityShanghai 200062China Institute for Quantum Information&State Key Laboratory of High Performance Computing College of ComputerNational University of Defense TechnologyChangsha 410073China Tianjin Institute of Advanced Technology Tianjin 300459China

In distributed quantum computing(DQC),quantum hardware design mainly focuses on providing as many as possible high-quality inter-chip ***,quantum software tries its best to reduce the required number of remote quantum gates between ***,this“hardware first,software follows”methodology may not fully exploit the potential of *** by classical software-hardware co-design,this paper explores the design space of application-specific DQC *** specifically,we propose Auto Arch,an automated quantum chip network(QCN)structure design *** qubits grouping followed by a customized QCN design,AutoArch can generate a near-optimal DQC architecture suitable for target quantum *** results show that the DQC architecture generated by Auto Arch can outperform other general QCN architectures when executing target quantum algorithms.

关键词： distributed quantum computing quantum architecture quantum circuit partitioning

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A PEEC-informed Deep Learning Approach for Inverse Electromagnetic Problem in Heterogeneous Integrations

A PEEC-informed Deep Learning Approach for Inverse Electroma...

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2023 IEEE Symposium on Electromagnetic Compatibility and Signal/Power Integrity, EMC+SIPI 2023

作者： Jiang, Yang Gao, Richard Xian-Ke Agency for Science Technology and Research Singapore Institute of High Performance Computing Singapore

ISBN: (纸本)9798350309768

In this paper, a partial element equivalent circuit (PEEC) informed deep learning approach is proposed for inverse electromagnetic scattering problems involving finite-sized dielectrics. To balance the enormous learning space and limited computation resources, a partial-relative-permittivity (PRP) model is proposed based on the compact PEEC model, which is capable to reveal the electromagnetic (EM) behavior of three-dimensional (3-D) heterogeneous structures by a 2.5-dimensional (2.5-D) representation. A tailored generative adversarial network (GAN) is developed to learn the intrinsic relation between the PRP model and the near-field information. To imitate the real-world phenomenon with adequate and accurate data, a dedicated training dataset is built numerically. With the GAN model, a PRP model can be interpreted from the measured phaseless magnetic fields at a single frequency, resulting in a broad-band c-PEEC model that is especially useful in power integrity and radiated emission analysis. © 2023 IEEE.

关键词： Integral equations

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Modeling probabilistic radar rainfall estimation at ungauged locations based on spatiotemporal errors which correspond to gauged data

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Hydrology Research 2015年第1期46卷 39-59页

作者： Wu, Shiang-Jen Lien, Ho-Cheng Hsu, Chih-Tsung Chang, Che-Hao Shen, Jhih-Cyuan National Center for High-Performance Computing Hsinchu30076 Taiwan Department of Civil Engineering National Taipei University of Technology Taipei10608 Taiwan

This study presents a probabilistic radar rainfall estimation (PRRE) model to quantify the reliability and accuracy of the resulting radar rainfall estimates at ungauged locations from a radar-based quantitative precipitation estimation (QPE) model. This model primarily estimates the quantiles of the radar rainfall errors at ungauged locations by incorporating seven spatiotemporal variogram models with a nonparametric sample quantile estimate method based on the radar rainfall errors at rain gauges. Then, by adding the resulting error quantiles to the radar rainfall estimates, the corresponding radar rainfall quantiles can be obtained. The QPE system Quantitative Precipitation Estimation Using Multiple Sensors (QPESUMS) provides hourly observed and radar precipitation for three typhoons in the Shinmen reservoir watershed in Northern Taiwan, which are used in the model development and validation. The results indicate that the proposed PRRE model can quantify the spatial and temporal variations of radar rainfall estimates at ungauged locations provided by the QPESUMS system. Also, its reliability and accuracy could be evaluated based on a 95% confidence interval and occurrence probability resulting from the cumulative probability distribution established by the proposed PRRE model. © IWA Publishing 2015.

关键词： Errors

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CRL： Efficient Concurrent Regeneration Codes with Local Reconstruction in Geo-Distributed Storage Systems

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Journal of Computer Science & technology 2018年第6期33卷 1140-1151页

作者： Quan-Qing Xu Wei-Ya Xi Khai Leong Yong Chao Jin Institute of High Performance Computing Agency for Science Technology and Research Singapore 138632 Singapore Data Storage Institute Agency for Science Technology and Research Singapore 138632 Singapore Institute for Infocomm Research Agency for Science Technology and Research Singapore 138632 Singapore

As a typical erasure coding choice, Reed-Solomon （RS） codes have such high repair cost that there is a penaltyfor high reliability and storage efficiency, thereby they are not suitable in geo-distributed storage systems. We present anovel family of concurrent regeneration codes with local reconstruction （CRL） in this paper. The CRL codes enjoy threebenefits. Firstly, they are able to minimize the network bandwidth for node repair. Secondly, they can reduce the numberof accessed nodes by calculating parities from a subset of data chunks and using an implied parity chunk. Thirdly, they arefaster than existing erasure codes for reconstruction in geo-distributed storage systems. In addition, we demonstrate howthe CRL codes overcome the limitations of the Reed-Solomon codes. We also illustrate analytically that they are excellent inthe trade-off between chunk locality and minimum distance. Furthermore, we present theoretical analysis including latencyanalysis and reliability analysis for the CRL codes. By using quantity comparisons, we prove that CRL（6, 2, 2） is only0.657x of Azure LRC（6, 2, 2）, where there are six data chunks, two global parities, and two local parities, and CRL（10,4, 2） is only 0.656x of HDFS-Xorbas（10, 4, 2）, where there are 10 data chunks, four local parities, and two global paritiesrespectively, in terms of data reconstruction times. Our experimental results show the performance of CRL by conductingperformance evaluations in both two kinds of environments： 1） it is at least 57.25% and 66.85% more than its competitorsin terms of encoding and decoding throughputs in memory, and 2） it has at least 1.46x and 1.21x higher encoding anddecoding throughputs than its competitors in JBOD （Just a Bunch Of Disks）. We also illustrate that CRL is 28.79% and30.19% more than LRC on encoding and decoding throughputs in a geo-distributed environment.

关键词： concurrent regeneration code local reconstruction geo-distributed storage system

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Solving traveling salesman problems by genetic algorithms

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自然科学进展（英文版） 2003年第2期13卷 135-141页

作者： LIANG Yanchun GE Hongwei Zhou Chunguang LEE Heow Pueh LIN Wuzhong LIM Siak Piang LEE Kwok Hong College of Computer Science and Technology Jilin University Changchun 130012 China Key Laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences Beijing 100080 China Institute of High Performance Computing Singapore 117528 Singapore College of Mathematics Science Jilin University Changchun 130012 China College of Computer Science and Technology Jilin University Changchun 130012 China Institute of High Performance Computing Singapore 117528 Singapore Department of Mechanical Engineering National University of Singapore Singapore 119260 Singapore

The gene section ordering on solving traveling salesman problems is analyzed by numerical experiments. Some improved crossover operations are presented. Several combinations of genetic operations are examined and the functions of these operations are analyzed. The essentiality of the ordering of the gene section and the significance of the evolutionary inversion operation are discussed. Some results and conclusions are obtained and given, which provide useful information for the implementation of the genetic operations for solving the traveling salesman problem.

关键词： genetic algorithms traveling salesman problem gene section evolutionary inversion genetic operations

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A Layer-Based Mesh Generator and Scheme for 3D Printing Simulation

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Computer Modeling in Engineering & Sciences 2019年第8期120卷 363-374页

作者： Ming-Hsiao Lee Shou-I Chen Wen-Hwa Chen Ying Mao National Center for High-performance Computing NARLHsinchu 30013Taiwan China University of Technology TaipeiTaiwan National Tsing Hua University Hsinchu 30013Taiwan

3D Printing,also called Additive Manufacturing,has become a promising manufacturing method to produce parts in various fields as it can produce parts even with very irregular shapes in a relatively shorter process and ***,during the printing process,some problems could decrease the accuracy and quality of the printed parts,such as warpage due to thermal strains,deformation due to inadequate supports,*** finite element method is most commonly adopted to evaluate engineering problems in advance to reduce possible failures;however,the element meshes,needed for analyses,are always irregularly distributed,especially for irregular objects,and cannot match the layer-by-layer growing shapes of the printed parts in the 3D printing *** a proper element mesh,the analysis cannot be *** overcome this problem,a layer-based mesh generator combined with a corresponding scheme for the 3D Printing simulation is proposed and *** the proposed methods,the analysis models can be designed and generated to match the growing shapes,i.e.,layer-by-layer,and used to simulate the layer-by-layer growing behavior in the 3D printing ***,the proposed schemes directly adopt the Stereo-Lithography(STL)formatted geometric data as the geometry model on which the mesh generation and simulation are *** makes them even easier to use since the STL geometry format is a De facto standard format used in the 3D printing *** simulation cases have been conducted to demonstrate the effectiveness and efficiency of these proposed schemes.

关键词： 3D printing mesh generator layer-by-layer layer-based

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LOCAL SUPERCONVERGENCE OF CONTINUOUS GALERKIN SOLUTIONS FOR DELAY DIFFERENTIAL EQUATIONS OF PANTOGRAPH TYPE

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Journal of Computational Mathematics 2016年第2期34卷 186-199页

作者： Xiuxiu Xu Qiumei Huang Hongtao Chen Beijing Institute for Scientific and Engineering Computing Beijing University of Technology Beijing 100124 China School of Mathematical Sciences and Fujian Provincial Key Laboratory on Mathematical Modeling and High Performance Scientific Computing Xiamen University Xiamen 361005 China

This paper is concerned with the superconvergent points of the continuous Galerkin solutions for delay differential equations of pantograph type. We prove the local nodal superconvergence of continuous Galerkin solutions under uniform meshes and locate all the superconvergent points based on the supercloseness between the continuous Galerkin solution U and the interpolation Hhu of the exact solution u. The theoretical results are illustrated by numerical examples.

关键词： Pantograph delay differential equations Uniform mesh Continuous Galerkinmethods Supercloseness Superconvergence.

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Solving the subset sum problem by the quantum Ising model with variational quantum optimization based on conditional values at risk

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Science China(Physics,Mechanics & Astronomy) 2024年第8期67卷 43-55页

作者： Qilin Zheng Miaomiao Yu Pingyu Zhu Yan Wang Weihong Luo Ping Xu Institute for Quantum Information and State Key Laboratory of High Performance Computing College of Computer Science and TechnologyNational University of Defense TechnologyChangsha 410073China Hefei National Laboratory Hefei 230088China

The subset sum problem is a combinatorial optimization problem,and its complexity belongs to the nondeterministic polynomial time complete(NP-Complete)*** problem is widely used in encryption,planning or scheduling,and integer *** accurate search algorithm with polynomial time complexity has not been found,which makes it challenging to be solved on classical *** effectively solve this problem,we translate it into the quantum Ising model and solve it with a variational quantum optimization method based on conditional values at *** proposed model needs only n qubits to encode 2ndimensional search space,which can effectively save the encoding quantum *** model inherits the advantages of variational quantum algorithms and can obtain good performance at shallow circuit depths while being robust to noise,and it is convenient to be deployed in the Noisy Intermediate Scale Quantum *** investigate the effects of the scalability,the variational ansatz type,the variational depth,and noise on the ***,we also discuss the performance of the model under different conditional values at *** computer simulation,the scale can reach more than nine *** selecting the noise type,we construct simulators with different QVs and study the performance of the model with *** addition,we deploy the model on a superconducting quantum computer of the Origin Quantum technology Company and successfully solve the subset sum *** model provides a new perspective for solving the subset sum problem.

关键词： subset sum problem quantum Ising model conditional values at risk variational quantum optimization

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