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arXiv 2025年

作者： de Hoop, Maarten V. Lassas, Matti Lu, Jinpeng Oksanen, Lauri Zhao, Ziyao Computational and Applied Mathematics and Earth Science Rice University HoustonTX77005 United States Department of Mathematics and Statistics University of Helsinki HelsinkiFI-00014 Finland

We study the inverse problem of determining a Signorini obstacle from boundary measurements for the isotropic elasticity system. We prove that the obstacle can be uniquely determined by a single measurement of displacement and normal stress for the Signorini problem on an open subset of the boundary up to a natural obstruction. In addition to considering the Signorini problem, we develop techniques that can be used to study inverse problems for general differential *** Codes 35R30, 74M15 Copyright © 2025, The Authors. All rights reserved.

关键词： Inverse problems

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A Neural Network Architecture Based on Attention Gate Mechanism for 3D Magnetotelluric Forward Modeling

arXiv

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arXiv 2025年

作者： Zhong, Xin Lin, Weiwei Pan, Kejia Wu, Pinxia Zhang, Jiajing Zhan, Zhiliang Xiao, Wenbo School of information engineering Jiangxi University of Science and Technology Ganzhou341000 China Jiangxi College of Applied Technology Ganzhou341000 China Key Laboratory of Ionic Rare Earth Resources and Environment Ministry of Natural Resources Ganzhou341000 China Hunan Shaofeng Institute for Applied Mathematics Xiangtan411105 China School of Mathematics and Statistics HNP-LAMA Central South University Changsha410083 China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics Beijing100088 China School of science Jiangxi University of Science and Technology Jiangxi Ganzhou341000 China

—Traditional three-dimensional magnetotelluric (MT) numerical forward modeling methods, such as the finite element method (FEM) and finite volume method (FVM), suffer from high computational costs and low efficiency due to limitations in mesh refinement and computational resources. We propose a novel neural network architecture named MTAGU-Net, which integrates an attention gating mechanism for 3D MT forward modeling. Specifically, a dual-path attention gating module is designed based on forward response data images and embedded in the skip connections between the encoder and decoder. This module enables the fusion of critical anomaly information from shallow feature maps during the decoding of deep feature maps, significantly enhancing the network’s capability to extract features from anomalous regions. Furthermore, we introduce a synthetic model generation method utilizing 3D Gaussian random field (GRF), which accurately replicates the electrical structures of real-world geological scenarios with high fidelity. Numerical experiments demonstrate that MTAGU-Net outperforms conventional 3D U-Net in terms of convergence stability and prediction accuracy, with the structural similarity index (SSIM) of the forward response data consistently exceeding 0.98. Moreover, the network can accurately predict forward response data on previously unseen datasets models, demonstrating its strong generalization ability and validating the feasibility and effectiveness of this method in practical applications. Copyright © 2025, The Authors. All rights reserved.

关键词： Decoding

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Prediction of methylene blue dye sorption to sulfonated date palm kernel biochar using statistical regression and machine learning methods and DFT studies

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Journal of Molecular Liquids 2025年 429卷

作者： Aigbe, Uyiosa Osagie Ukhurebor, Kingsley Eghonghon Onyancha, Robert Birundu Osibote, Adelaja Otolorin Hassaan, Mohamed A. ElKatory, Marwa R. Nemr, Ahmed El Center for Space Research North-West University Private Bag X6001 Potchefstroom2531 South Africa National Institute of Theoretical and Computational Science Johannesburg2000 South Africa School of Chemistry & Physics University of KwaZulu-Natal Pietermaritzburg Campus Private Bag X01 Scottsville3209 South Africa Department of Physics Faculty of Science Edo State University Uzairue Edo State Nigeria School of Physics and Earth Science Faculty of Applied Science and Technology Technical University of Kenya Nairobi Kenya College of Graduate Studies School of Interdisciplinary Research and Graduate Studies Muckleneuk Campus University of South Africa Pretoria0003 South Africa Department of Mathematics and Physics Cape Peninsula University of Technology Cape Town South Africa Kayet Bey Alexandria Elanfoushy Egypt Advanced Technology and New Materials Research Institute SRTA-City New Borg El-Arab City 21934 Alexandria Egypt

In this study, methylene blue (MB) dye adsorption to synthesised sulfonated date palm kernel biochar (SDPKB) was predicted and optimized using statistical-based regression approach (response surface methodology (RSM), machine-learning algorithms (artificial-neural-network (ANN), and adaptive-neuro-fuzzy-inference-system (ANFIS) models), and quantum chemistry calculations performed using density function theory (DFT) to link the electrical properties of the MB dye with the experimental findings. The percentage (%) of MB dye removed using SDPKB was found to be proportional to the biosorbent dosage and interaction time and inversely proportional to the solution pH and initial concentrations based on different used models results. It was observed that these models were accurate and comparable for the prediction of the removal of MB with coefficient of regression (R2) values of 0.9174, 0.9742, and 0.9999, mean square error (MSE) values of 181.71, 94.50, and 0.00000049, and root MSE (RMSE) values of 13.48, 9.72, and 0.0007 for the RSM, ANN, and ANFIS, respectively. The ANFIS model was found to be more effective in the prediction of MB sorption to SDPKB than the other models (ANFIS > ANN > RSM), and it was highly applicable in the sorption process. This study has revealed that the SDPKB can serve as a better biosorbent for MB adsorption. Therefore, this study will serve as a first reference point data that will be of great assistance in industrial effluent management as well as decision-making on the adoption of statistical and machine learning models for adsorption study. © 2025 Elsevier B.V.

关键词： Adversarial machine learning

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Lattice Boltzmann flow simulations with applications of reduced order modeling techniques

Lattice Boltzmann flow simulations with applications of redu...

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International Petroleum Technology Conference 2014: Unlocking Energy Through Innovation, Technology and Capability, IPTC 2014

作者： Brown, Donald L. Li, Jun Calo, Victor M. Ghommem, Mehdi Efendiev, Yalchin Applied Mathematics and Computational Science Earth and Environmental Sciences and Engineering King Abdullah University of Science and Technology Thuwal Saudi Arabia Department of Mathematics ISC Texas A and M University College Station TX United States

ISBN: (纸本)9781632660053

With the recent interest in shale gas, an understanding of the flow mechanisms at the pore scale and beyond is necessary, which has attracted a lot of interest from both industry and academia. One of the suggested algorithms to help understand flow in such reservoirs is the Lattice Boltzmann Method (LBM). The primary advantage of LBM is its ability to approximate complicated geometries with simple algorithmic modificatoins. In this work, we use LBM to simulate the flow in a porous medium. More specifically, we use LBM to simulate a Brinkman type flow. The Brinkman law allows us to integrate fast free-flow and slow-flow porous regions. However, due to the many scales involved and complex heterogeneities of the rock microstructure, the simulation times can be long, even with the speed advantage of using an explicit time stepping method. The problem is two-fold, the computational grid must be able to resolve all scales and the calculation requires a steady state solution implying a large number of timesteps. To help reduce the computational complexity and total simulation times, we use model reduction techniques to reduce the dimension of the system. In this approach, we are able to describe the dynamics of the flow by using a lower dimensional subspace. In this work, we utilize the Proper Orthogonal Decomposition (POD) technique, to compute the dominant modes of the flow and project the solution onto them (a lower dimensional subspace) to arrive at an approximation of the full system at a lowered computational cost. We present a few proof-of-concept examples of the flow field and the corresponding reduced model flow field. Copyright 2014, International Petroleum Technology Conference.

关键词： Flow fields

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A FOLIATED AND REVERSIBLE FINSLER MANIFOLD IS DETERMINED BY ITS BROKEN SCATTERING RELATION

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Pure and applied Analysis 2021年第4期3卷 789-811页

作者： DE HOOP, Maarten V. Ilmavirta, Joonas Lassas, Matti Saksala, Teemu Departments of Computational and Applied Mathematics Earth Science Rice University Houston TX United States Department of Mathematics and Statistics University of Jyväskylä Jyväskylä Finland Department of Mathematics and Statistics University of Helsinki Helsinki Finland Department of Mathematics North Carolina State University Raleigh NC United States

The broken scattering relation consists of the total lengths of broken geodesics that start from the boundary, change direction once inside the manifold, and propagate to the boundary. We show that if two reversible Finsler manifolds satisfying a convex foliation condition have the same broken scattering relation, then they are isometric. This implies that some anisotropic material parameters of the earth can be in principle reconstructed from single scattering measurements at the surface. © 2021, Mathematical sciences Publishers. All rights reserved.

关键词： anisotropic elasticity distance functions Finsler manifold scattering relation

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Elasticity and acoustic velocities of δ−AlOOH at extreme conditions: A methodology assessment

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Physical Review Materials 2024年第10期8卷 103601页

作者： Chenxing Luo (罗晨星) Yang Sun (孙阳) Renata M. Wentzcovitch Department of Applied Physics and Applied Mathematics Department of Physics Department of Earth and Environmental Sciences Lamont–Doherty Earth Observatory Data Science Institute Center for Computational Quantum Physics

Hydrous phases play a fundamental role in the deep-water cycle on earth. Understanding their stability and thermoelastic properties is essential for constraining their abundance using seismic tomography. However, determining their elastic properties at extreme conditions is notoriously challenging. The challenges stem from the complex behavior of hydrogen bonds under high pressures and temperatures (P,Ts). In this study, we evaluate how advanced molecular dynamics simulation techniques can address these challenges by investigating the adiabatic elasticity and acoustic velocities of δ−AlOOH, a critical and prototypical high-pressure hydrous phase. We compared the performances of three methods to assess their viability and accuracy. The thermoelastic tensor was computed up to 140 GPa and temperatures up to 2700 K using molecular dynamics with a DeePMD machine-learning interatomic potential based on the SCAN meta-GGA functional. The excellent agreement with ambient condition single-crystal ultrasound measurements and the correct description of velocity changes induced by H-bond disorder-symmetrization transition observed at 10 GPa in Brillouin scattering measurements underscores the accuracy and efficacy of our approach.

关键词： Elasticity Geophysics High-pressure studies Hydrogen bonds Disordered systems Minerals Molecular dynamics

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Subsalt imaging with internal multiples 78

Subsalt imaging with internal multiples

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78th Society of Exploration Geophysicists International Exposition and Annual Meeting, SEG 2008

作者： Malcolm, Alison E. Ursin, Bjørn De Hoop, Maarten V. Department of Earth Atmospheric and Planetary Sciences MIT United States Department of Petroleum Engineering and Applied Geophysics Norwegian University of Science and Technology Norway Center for Computational and Applied Mathematics Geo-Mathematical Imaging Group Purdue University United States

ISBN: (纸本)9781605607856

If singly scattered seismic waves illuminate the entirety of a subsurface structure of interest, standard methods can be applied to image it. In many cases, subsalt imaging for example, a combination of restricted acquisition geometry and imperfect velocity models results in regions of the model that are not illuminated with singly scattered waves. We present an approach to use multiply scattered waves to illuminate such structures, and illustrate the method by creating images of the base of salt with an erroneous velocity model. This method builds upon past work in which methods to predict artifacts in imaging from multiply scattered waves have been developed and shares similarities with current techniques of imaging with surface-related multiples. Copyright © (2008) by the Society of Exploration Geophysicists All rights reserved.

关键词： Subsalt imaging

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A simulation study of protons heated by left/right-handed Alfvén waves generated by electromagnetic proton-proton instability

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Plasma science and Technology 2021年第12期23卷 55-62页

作者： Jiansheng YAO Yingkui ZHAO Difa YE Yi LI Lihui CHAI Jicheng SUN Institute of Applied Physics and Computational Mathematics Beijing 100088People's Republic of China CAS Key Lab of Geospace Environment School of Earth and Space SciencesUniversity of Science and Technology of ChinaHefei 230026People's Republic of China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029People's Republic of China Key Laboratory of Polar Science Ministry of Natural ResourcesShanghai 200020People's Republic of China MNR Key Laboratory for Polar Science Polar Research Institute of ChinaShanghai 200136People's Republic of China

Most protons in the solar wind belong to one of two different populations,the less dense beam protons and the denser core *** beam protons,with a velocity of(1-2)V_(A)(V_(A)is the local Alfvén speed),always drift relative to the core protons;this kind of distribution is unstable and stimulates several kinds of wave *** this study,using a 2 D hybrid simulation model,we find that the original right-handed elliptically polarized Alfvén waves become linearly polarized,and eventually become right-handed and circularly *** that linearly polarized waves are a superposition of left-handed and right-handed waves,cyclotron resonance in the right-handed/left-handed component heats beam/core protons *** resonance between beam protons and right-handed polarized waves is stronger when the beam relative density is lower,resulting in more dramatic perpendicular heating of beam protons,whereas the situation is reversed when the beam relative density is larger.

关键词： proton/proton instability hybrid simulation Alfvén waves

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Agent-based Algorithm for Spatial Distribution of Objects

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Procedia Computer science 2012年 9卷 1494-1502页

作者： Nathan Collier Marcin Sieniek Applied Mathematics and Computational Science and Earth and Environmental Sciences and Engineering King Abdullah University of Science and Technology Thuwal Saudi Arabia AGH University of Science and Technology Kraków Poland

In this paper we present an agent-based algorithm for the spatial distribution of objects. The algorithm is a generalization of the bubble mesh algorithm, initially created for the point insertion stage of the meshing process of the finite element method. The bubble mesh algorithm treats objects in space as bubbles, which repel and attract each other. The dynamics of each bubble are approximated by solving a series of ordinary differential equations. We present numerical results for a meshing application as well as a graph visualization application.

关键词： bubble mesh meshing graph visualization agent-based

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Mixed ray transform on simple 2-dimensional riemannian manifolds

arXiv

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arXiv 2018年

作者： de Hoop, Maarten V. Saksala, Teemu Zhai, Jian Simons Chair in Computational and Applied Mathematics and Earth Science Rice University HoustonTX77005 United States Department of Computational and Applied Mathematics Rice University HoustonTX77005 United States

We characterize the kernel of the mixed ray transform on simple 2-dimensional Riemannian manifolds, that is, on simple surfaces for tensors of any order.53C22 53C65 Copyright © 2018, The Authors. All rights reser...

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