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Multipath Components Modeling and Measuring in Device-Free Underground Parking Localization

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Multipath Components Modeling and Measuring in Device-Free U...

IEEE International Conference on Communications in China (ICCC)

作者： Sihai Yang Xing Xiao Xing Wang Zhuoting Chen Menggang Sheng Zhiqiang Yao School of Automation and Electronic Information Xiangtan University Xiangtan China Hunan Province Key Laboratory of Credible Intelligent Navigation and Positioning Key Laboratory of Intelligent Computing and Information Processing of Ministry of Education National Center for Applied Mathematics in Hunan Xiangtan University Xiangtan China School of Mathematics and Computational Science Xiangtan University Xiangtan China

ISBN: (数字)9798350378412

ISBN: (纸本)9798350378429

The Device-Free Localization (DFL) system hold significant application value in NLOS (Non-Line-of-Sight) environments where GPS signals are unavailable. It is a challenge to accurately distinguish whether the changes in spatial signals are caused by the presence of users or the changes of environment, particularly in Non-Line-of-Sight (NLOS) environments without GPS signals. To address this issue, we proposes a DFL method utilizing Multipath Components (MPCs), which involves a detailed analysis of how the presence of users affects the MPCs. Specifically, a calculation method for signal propagation paths using virtual anchors has been developed to accurately construct a user-based diffraction model. An algorithm for extracting MPCs from actual signal measurements was also proposed. The maximum average absolute error between the simulated and measured MPC amplitudes with UWB was 0.9461 dB, validating the possibility of substituting simulation models for actual measurements. Moreover, by utilizing a deep learning network with MPCs as input features, the DFL method achieves a positioning accuracy of 0.44 m in an underground parking with only two sensors. This represents an improvement of $\mathbf{0. 3 5 m}$ over traditional RSS-based fingerprinting localization methods.

关键词： Location awareness Deep learning Accuracy Diffraction Measurement uncertainty Sensor phenomena and characterization Fingerprint recognition

QCLAB++: Simulating Quantum Circuits on GPUs

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arXiv 2023年

作者： Van Beeumen, Roel Camps, Daan Mehta, Neil Applied Mathematics and Computational Research Division Lawrence Berkeley National Laboratory BerkeleyCA United States National Energy Research Scientific Computing Center Lawrence Berkeley National Laboratory BerkeleyCA United States

We introduce qclab++, a light-weight, fully-templated C++ package for GPU-accelerated quantum circuit simulations. The code offers a high degree of portability as it has no external dependencies and the GPU kernels are generated through OpenMP offloading. qclab++ is designed for performance and numerical stability through highly optimized gate simulation algorithms for 1-qubit, controlled 1-qubit, and 2-qubit gates. Furthermore, we also introduce qclab a quantum circuit toolbox for Matlab with a syntax that mimics qclab++. This provides users the flexibility and ease of use of a scripting language like Matlab for studying their quantum algorithms, while offering high-performance GPU acceleration when required. As such, the qclab++ library offers a unique combination of features. We compare the CPU simulator in qclab++ with the GPU kernels generated by OpenMP and observe a speedup of over 40×. Furthermore, we also compare qclab++ to other circuit simulation packages, such as cirq-qsim and qibo, in a series of benchmarks conducted on NERSC’s Perlmutter system and illustrate its competitiveness. Copyright © 2023, The Authors. All rights reserved.

关键词： Circuit simulation

Study on the structure, elasticity, and thermal conductivity of orthocarbonate Sr₂CO₄

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Results in Physics 2024年 61卷

作者： Liu, Zi-Jiang Ju, Jia-Qi Dou, Xi-Long Jin, Neng-Zhi Zhang, Cai-Rong Wang, Xiao-Yun Wu, Liang School of Mathematics and Physics Lanzhou Jiaotong University Lanzhou 730070 China Key Laboratory of Cloud Computing of Gansu Province Gansu Computing Center Lanzhou 730030 China Department of Applied Physics Lanzhou University of Technology Lanzhou 730050 China

Orthocarbonate Sr2CO4 is a recently discovered Sr-carbonate that plays a crucial role in understanding the global long-term carbon cycle. In this work, the structure, equation of state, elasticity, and thermal conduct... 详细信息

Orthocarbonate Sr₂CO₄ is a recently discovered Sr-carbonate that plays a crucial role in understanding the global long-term carbon cycle. In this work, the structure, equation of state, elasticity, and thermal conductivity of Sr₂CO₄ were studied by first-principles calculations. The results show that the surfaces of the SrO₉ and SrO₁₁ polyhedrons, which make up Sr₂CO₄, are composed of triangles and quadrangles. By comparison with other alkaline earth metal orthocarbonates, SrCO₃ polymorphs, and the Preliminary Reference Earth Model (PREM), Sr₂CO₄ is found to be a carbonate with high density, low wave velocity, low anisotropy, and low thermal conductivity in the entire Earth's mantle. This study may help to understand the high-pressure behavior of alkaline earth metal orthocarbonates in the Earth's interior. © 2024 The Author(s)

关键词： Anisotropy Elasticity Sr2CO4 Structure Thermal conductivity

Efficient Quantum Counting and Quantum Content-Addressable Memory for DNA similarity

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arXiv 2023年

作者： Balewski, Jan Klymko, Katherine Camps, Daan Tritt, Andrew National Energy Research Scientific Computing Center Lawrence Berkeley National Laboratory BerkeleyCA United States Applied Mathematics and Computational Research Division Lawrence Berkeley National Laboratory BerkeleyCA United States

We present QCAM, a quantum analogue of Content-Addressable Memory (CAM), useful for finding matches in two sequences of bit-strings. Our QCAM implementation takes advantage of Grover’s search algorithm and proposes a highly-optimized quantum circuit implementation of the QCAM oracle. Our circuit construction uses the parallel uniformly controlled rotation gates, which were used in previous work to generate QBArt encodings. These circuits have a high degree of quantum parallelism which reduces their critical depth. The optimal number of repetitions of the Grover iterator used in QCAM depends on the number of true matches and hence is input dependent. We additionally propose a hardware-efficient implementation of the quantum counting algorithm (HEQC) that can infer the optimal number of Grover iterations from the measurement of a single observable. We demonstrate the QCAM application for computing the Jaccard similarity between two sets of k-mers obtained from two DNA sequences. Copyright © 2023, The Authors. All rights reserved.

关键词： DNA

The ESPRIT algorithm under high noise: Optimal error scaling and noisy super-resolution

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arXiv 2024年

作者： Ding, Zhiyan Epperly, Ethan N. Lin, Lin Zhang, Ruizhe Department of Mathematics University of California Berkeley United States Department of Computing and Mathematical Sciences California Institute of Technology PasadenaCA United States Applied Mathematics and Computational Research Division Lawrence Berkeley National Laboratory United States Challenge Institute for Quantum Computation University of California Berkeley United States Simons Institute for the Theory of Computing United States

Subspace-based signal processing techniques, such as the Estimation of Signal Parameters via Rotational Invariant Techniques (ESPRIT) algorithm, are popular methods for spectral estimation. These algorithms can achieve the so-called super-resolution scaling under low noise conditions, surpassing the well-known Nyquist limit. However, the performance of these algorithms under high-noise conditions is not as well understood. Existing state-of-the-art analysis indicates that ESPRIT and related algorithms can be resilient even for signals where each observation is corrupted by statistically independent, mean-zero noise of size O(1), but these analyses only show that the error ∊ decays at a slow rate ∊ = O͂(n−1/2) with respect to the cutoff frequency n (i.e., the maximum frequency of the measurements). In this work, we prove that under certain assumptions, the ESPRIT algorithm can attain a significantly improved error scaling ∊ = O͂(n−3/2), exhibiting noisy super-resolution scaling beyond the Nyquist limit ∊ = O(n−1) given by the Nyquist-–Shannon sampling theorem. We further establish a theoretical lower bound and show that this scaling is optimal. Our analysis introduces novel matrix perturbation results, which could be of independent interest. © 2024, CC BY.

关键词： Cutoff frequency

MATRIX-FREE GPU-ACCELERATED SADDLE-POINT SOLVERS FOR HIGH-ORDER PROBLEMS IN H(div)

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arXiv 2023年

作者： Pazner, Will Kolev, Tzanio Vassilevski, Panayot Fariborz Maseeh Department of Mathematics and Statistics Portland State University PortlandOR United States Center for Applied Scientific Computing Lawrence Livermore National Laboratory LivermoreCA United States

This work describes the development of matrix-free GPU-accelerated solvers for high-order finite element problems in H(div). The solvers are applicable to grad-div and Darcy problems in saddle-point formulation, and have applications in radiation diffusion and porous media flow problems, among others. Using the interpolation–histopolation basis (cf. SIAM J. Sci. Comput., 45 (2023), A675–A702), efficient matrix-free preconditioners can be constructed for the (1, 1)-block and Schur complement of the block system. With these approximations, block-preconditioned MINRES converges in a number of iterations that is independent of the mesh size and polynomial degree. The approximate Schur complement takes the form of an M-matrix graph Laplacian, and therefore can be well-preconditioned by highly scalable algebraic multigrid methods. High-performance GPU-accelerated algorithms for all components of the solution algorithm are developed, discussed, and benchmarked. Numerical results are presented on a number of challenging test cases, including the "crooked pipe" grad-div problem, the SPE10 reservoir modeling benchmark problem, and a nonlinear radiation diffusion test case. Copyright © 2023, The Authors. All rights reserved.

关键词： Porous materials

An extended sequential quadratic method with extrapolation

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arXiv 2023年

作者： Zhang, Yongle Pong, Ting Kei Xu, Shiqi Department of Mathematics Visual Computing and Virtual Reality Key Laboratory of Sichuan Province Sichuan Normal University Chengdu China Department of Applied Mathematics the Hong Kong Polytechnic University Hong Kong Hong Kong Department of Mathematics Sichuan Normal University Chengdu China

We revisit and adapt the extended sequential quadratic method (ESQM) in [3] for solving a class of difference-of-convex optimization problems whose constraints are defined as the intersection of level sets of Lipschitz differentiable functions and a simple compact convex set. Particularly, for this class of problems, we develop a variant of ESQM, called ESQM with extrapolation (ESQMe), which incorporates Nesterov's extrapolation techniques for empirical acceleration. Under standard constraint qualifications, we show that the sequence generated by ESQMe clusters at a critical point if the extrapolation parameters are uniformly bounded above by a certain threshold. Convergence of the whole sequence and the convergence rate are established by assuming Kurdyka- Lojasiewicz (KL) property of a suitable potential function and imposing additional differentiability assumptions on the objective and constraint functions. In addition, when the objective and constraint functions are all convex, we show that linear convergence can be established if a certain exact penalty function is known to be a KL function with exponent 1/2;we also discuss how the KL exponent of such an exact penalty function can be deduced from that of the original extended objective (i.e., sum of the objective and the indicator function of the constraint set). Finally, we perform numerical experiments to demonstrate the empirical acceleration of ESQMe over a basic version of ESQM, and illustrate its effectiveness by comparing with the natural competing algorithm SCPls from [35]. Copyright © 2023, The Authors. All rights reserved.

关键词： Extrapolation

Adaptive time-stepping and maximum-principle preserving Lagrangian schemes for gradient flows

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arXiv 2025年

作者： Liu, Qianqian Chen, Wenbin Shen, Jie Cheng, Qing School of Mathematical Sciences Fudan University Shanghai200433 China Shanghai Key Laboratory for Contemporary Applied Mathematics School of Mathematical Sciences Fudan University Shanghai200433 China Eastern Institute of Technology Zhejiang Ningbo315200 China Key Laboratory of Intelligent Computing and Application Tongji University Ministry of Education Department of Mathematics Tongji University Shanghai200092 China

We develop in this paper an adaptive time-stepping approach for gradient flows with distinct treatments for conservative and non-conservative dynamics. For the non-conservative gradient flows in Lagrangian coordinates, we propose a modified formulation augmented by auxiliary terms to guarantee positivity of the determinant, and prove that the corresponding adaptive second-order Backward Difference Formulas (BDF2) scheme preserves energy stability and the maximum principle under the time-step ratio constraint 0 n ≤ rmax ≤ 32. On the other hand, for the conservative Wasserstein gradient flows in Lagrangian coordinates, we propose an adaptive BDF2 scheme which is shown to be energy dissipative, and positivity preserving under the time-step ratio constraint 0 n ≤ rmax ≤ 3+√217 in 1D and 0 n ≤ rmax ≤ 54 in 2D, respectively. We also present ample numerical simulations in 1D and 2D to validate the efficiency and accuracy of the proposed *** Codes 35K55, 35K65, 65M06, 65M12 Copyright © 2025, The Authors. All rights reserved.

关键词： Lagrange multipliers

Rectangular multiple-relaxation-time lattice Boltzmann method for the Navier-Stokes and nonlinear convection-diffusion equations: General equilibrium and some important issues

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Physical Review E 2023年第1期108卷 015304-015304页

作者： Zhenhua Chai (柴振华) Xiaolei Yuan (袁晓垒) Baochang Shi (施保昌) School of Mathematics and Statistics Huazhong University of Science and Technology Wuhan 430074 China Institute of Interdisciplinary Research for Mathematics and Applied Science Huazhong University of Science and Technology Wuhan 430074 China Hubei Key Laboratory of Engineering Modeling and Scientific Computing Huazhong University of Science and Technology Wuhan 430074 China College of Mathematics and Information Science Hebei University Baoding 071002 China

In this paper, we develop a general rectangular multiple-relaxation-time lattice Boltzmann (RMRT-LB) method for the Navier-Stokes equations (NSEs) and nonlinear convection-diffusion equation (NCDE) by extending our recent unified framework of the multiple-relaxation-time lattice Boltzmann (MRT-LB) method [Chai and Shi, Phys. Rev. E 102, 023306 (2020)], where an equilibrium distribution function (EDF) [Lu et al., Philos. Trans. R. Soc. A 369, 2311 (2011)] on a rectangular lattice is utilized. The anisotropy of the lattice tensor on a rectangular lattice leads to anisotropy of the third-order moment of the EDF, which is inconsistent with the isotropy of the viscous stress tensor of the NSEs. To eliminate this inconsistency, we extend the relaxation matrix related to the dynamic and bulk viscosities. As a result, the macroscopic NSEs can be recovered from the RMRT-LB method through the direct Taylor expansion method. Whereas the rectangular lattice does not lead to the change of the zero-, first- and second-order moments of the EDF, the unified framework of the MRT-LB method can be directly applied to the NCDE. It should be noted that the RMRT-LB model for NSEs can be derived on the rDdQq (q discrete velocities in d-dimensional space, d≥1) lattice, including rD2Q9, rD3Q19, and rD3Q27 lattices, while there are no rectangular D3Q13 and D3Q15 lattices within this framework of the RMRT-LB method. Thanks to the block-lower triangular relaxation matrix introduced in the unified framework, the RMRT-LB versions (if existing) of the previous MRT-LB models can be obtained, including those based on raw (natural) moment, central moment, Hermite moment, and central Hermite moment. It is also found that when the parameter cs is an adjustable parameter in the standard or rectangular lattice, the present RMRT-LB method becomes a kind of MRT-LB method for the NSEs and NCDE, and the commonly used MRT-LB models on the DdQq lattice are only its special cases. We also perform some numeric

关键词： Lattice-Boltzmann methods