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Simultaneous Approximation Terms for Elastic Wave Equations on Nonuniform Grids 25th

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Simultaneous Approximation Terms for Elastic Wave Equations ...

25th International Conference on Domain Decomposition Methods in science and engineering, DD 2018

作者： Gao, Longfei Keyes, David Division of Computer Electrical and Mathematical Sciences and Engineering King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

ISBN: (纸本)9783030567491

Numerical simulation of wave phenomena is routinely used in seismic studies, where simulated wave signals are compared against experimental ones to infer subterranean information. Various wave systems can be used to model wave propagation in earth media. Here, we consider the system of isotropic elastic wave equations described in Section 2. © 2020, Springer Nature Switzerland AG.

关键词： Wave propagation

Predicting Different Types of Imbalanced Intrusion Activities Based on a Multi-Stage Deep Learning Approach

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Predicting Different Types of Imbalanced Intrusion Activitie...

2021 International Conference on Information technology, ICIT 2021

作者： Qaddoura, Raneem Al-Zoubi, Ala'M. Almomani, Iman Faris, Hossam Philadelphia University Faculty of Information Technology Amman Jordan University of Granada School of Science Technology and Engineering Granada Spain Prince Sultan University Computer Science Department Riyadh Saudi Arabia The University of Jordan King Abdullah II School for Information Technology Amman Jordan

ISBN: (纸本)9781665428705

Intrusion Detection Systems for IoT networks have emerged to solve the vulnerabilities caused by the extensive utilization of IoT devices for different applications. Intrusion Detection Systems are not only limited to predicting the existence of intrusion activities apart from the normal ones but it is also extended to identify different types of intrusion activities that allow for a larger scale of recovery actions toward solving this security breach. This study proposes a deep learning approach to detect different types of intrusion activities using a multistage mechanism and an oversampling process which solves the problem of the imbalanced data produced by the IoT devices. This work confirms that the selected classification techniques are not able to detect all types of intrusion for imbalanced data if not combined with the oversampling process. It also compares the proposed approach with other classification and deep learning techniques which consider the oversampling process as part of their pre-processing phase. The results presented in this work show that the proposed approach outperforms the other techniques in terms of Accuracy and G-mean and has an advantage over the other techniques in predicting the different types of intrusion in terms of Precision and Recall. © 2021 IEEE.

关键词： Intrusion detection

SELF-REGULATED BIOLOGICAL TRANSPORTATION STRUCTURES WITH GENERAL ENTROPY DISSIPATION: 2D CASE AND LEAF-SHAPED DOMAIN

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arXiv 2024年

作者： Astuto, Clarissa Markowich, Peter Portaro, Simone Russo, Giovanni Mathematical and Computer Sciences and Engineering Division King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia Department of Mathematics and Computer Sciences University of Catania 95125 Italy Faculty of Mathematics University of Vienna Oskar-Morgenstern-Platz 1 Vienna1090 Austria Department of Mathematics and Computer Sciences University of Catania 95125 Italy

In recent years, the study of biological transportation networks has attracted significant interest, focusing on their self-regulating, demand-driven nature. This paper examines a mathematical model for these networks, featuring nonlinear elliptic equations for pressure and an auxiliary variable, and a reaction-diffusion parabolic equation for the conductivity tensor, introduced in [19]. The model, based on an energy functional with diffusive and metabolic terms, allows for various entropy generating functions, facilitating its application to different biological scenarios. We proved a local well-posedness result for the problem in Hölder spaces employing Schauder and semigroup theory. Then, after a suitable parameter reduction through scaling, we computed the numerical solution for the proposed system using a recently developed ghost nodal finite element method [6]. An interesting aspect emerges when the solution is very articulated and the branches occupy a wide region of the domain. © 2024, CC BY.

关键词： Partial differential equations

Exploring the non-Hermitian topology of exceptional points in lasers and fiber loops

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Exploring the non-Hermitian topology of exceptional points i...

2023 Conference on Lasers and Electro-Optics Europe and European Quantum Electronics Conference, CLEO/Europe-EQEC 2023

作者： Schumer, Alexander Nasari, Hadiseh Liu, Yuzhou G.N. Lopez-Galmiche, Gisela Leshin, Jason Lopez-Aviles, Helena E. Ding, Lei Alahmadi, Yousef Hassan, Absar U. Zhong, Qi Rotter, Stefan LiKamWa, Patrick Christodoulides, Demetrios N. Khajavikhan, Mercedeh ViennaA-1040 Austria Ming Hsieh Department of Electrical and Computer Engineering University of Southern California Los AngelesCA90089 United States CREOL The College of Optics & Photonics University of Central Florida OrlandoFL United States Center of Excellence for Telecomm Applications Joint Centers of Excellence Program King Abdul Aziz City for Science and Technology Riyadh11442 Saudi Arabia Department of Physics & Astronomy University of Southern California Los AngelesCA United States

ISBN: (纸本)9798350345995

When non-Hermitian eigenvalue surfaces form intertwined Riemann surfaces, the corresponding non-Hermitian singularities, also know as exceptional points (EPs), are located at the center of this specific topology. Various experimental platforms have recently been presented in which interesting new physics associated with these branch point singularities can be explored. In particular, it has been shown that dynamically encircling EPs may lead to a so-called chiral state transfer. The chirality in this context refers to the fact that in such an encircling protocol, the final state at the end of an EP-enclosing loop solely depends on the encircling direction (clockwise or counterclockwise), but not on the initial state. Such a chiral behavior is intrinsically linked to the state vector deviating from adiabatically following the system's eigenstates associated with the eigenvalue surfaces;instead, due to the non-Hermitian violation of the adiabatic theorem, non-adiabatic jumps let the system undergo transitions from lossy eigenstates to eigenstates with gain. Here, we present two experiments that implement concepts that go beyond this established paradigm. © 2023 IEEE.

关键词： Topology

On the Internal Resonance Modes of Time Domain Surface Integral Equations for Acoustic Transmission Problems

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On the Internal Resonance Modes of Time Domain Surface Integ...

General Assembly and Scientific Symposium, URSI

作者： Rui Chen Hakan Bagci Division of Computer Electrical and Mathematical Science and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia

The internal resonance problem pertinent to time domain surface integral equations (SIEs) for analyzing transient acoustic scattering from penetrable objects is investigated. The first equation considered here is constructed by combining SIE representations of the internal and external problems via the continuity of the velocity potential and its normal derivative. Just like its frequency-domain counterpart, this equation suffers from the internal resonance problem. But it is demonstrated in this work that, unlike the frequency-domain solution, by increasing the accuracy of the discretization, the amplitude of these spurious modes can be suppressed to a level that does not significantly affect the solution. The second equation considered here is obtained by linearly combining the first equation with its normal derivative and its solution is completely free from spurious internal resonance modes.

关键词： Frequency-domain analysis Integral equations Acoustic scattering Acoustics Time-domain analysis Transient analysis

Online Federated Learning via Non-Stationary Detection and Adaptation amidst Concept Drift

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arXiv 2022年

作者： Ganguly, Bhargav Aggarwal, Vaneet The School of Industrial Engineering Purdue University West LafayetteIN47907 United States Computer Science King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

Federated Learning (FL) is an emerging domain in the broader context of artificial intelligence research. Methodologies pertaining to FL assume distributed model training, consisting of a collection of clients and a server, with the main goal of achieving optimal global model with restrictions on data sharing due to privacy concerns. It is worth highlighting that the diverse existing literature in FL mostly assume stationary data generation processes;such an assumption is unrealistic in real-world conditions where concept drift occurs due to, for instance, seasonal or period observations, faults in sensor measurements. In this paper, we introduce a multiscale algorithmic framework which combines theoretical guarantees of FedAvg and FedOMD algorithms in near stationary settings with a non-stationary detection and adaptation technique to ameliorate FL generalization performance in the presence of concept drifts. We present a multi-scale algorithmic framework leading to (Equation presented) dynamic regret for T rounds with an underlying general convex loss function, where L is the number of times non-stationary drifts occurred and ∆ is the cumulative magnitude of drift experienced within T rounds. Copyright © 2022, The Authors. All rights reserved.

关键词： E-learning

Robust globally divergence-free HDG finite element method for steady thermally coupled incompressible MHD flow

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arXiv 2024年

作者： Zhang, Min Zhu, Zimo Zhai, Qijia Xie, Xiaoping Institute of Mathematics Henan Academy of Sciences Zhengzhou450046 China College of Mathematies and Information Science Henan Normal University Xinxiang453007 China Chengdu aircraft design and Research Institute Chengdu610041 China School of Mathematics Sichuan University Chengdu610064 China Computer Electrical and Mathematical Science and Engineering Division King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

This paper develops an hybridizable discontinuous Galerkin (HDG) finite element method of arbitrary order for the steady thermally coupled incompressible Magnetohydrodynamics (MHD) flow. The HDG scheme uses piecewise polynomials of degrees k(k ≥ 1), k, k − 1, k − 1 and k respectively for the approximations of the velocity, the magnetic field, the pressure, the magnetic pseudo-pressure, and the temperature in the interior of elements, and uses piecewise polynomials of degree k for their numerical traces on the interfaces of elements. The method is shown to yield globally divergence-free approximations of the velocity and magnetic fields. Existence and uniqueness results for the discrete scheme are given and optimal a priori error estimates are derived. Numerical experiments are provided to verify the obtained theoretical results. © 2024, CC BY.

关键词： Galerkin methods

∂H: Differentiable Holography

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Research Square

Research Square 2023年

作者： Chen, Ni Wang, Congli Heidrich, Wolfgang Wyant College of Optical Sciences University of Arizona TucsonAZ85721 United States Department of Electrical Engineering & Computer Sciences University of California BerkeleyCA94720 United States Visual Computing Center King Abdullah University of Science and Technology Thuwal23955 Saudi Arabia

Over the past decade, the field of holography has gained significant ground due to advances in computational imaging. However, the utilization of computational tools is hampered by the mismatch between experimental setups and the conceptual model. We present differentiable holography (∂H), a novel framework for automatically self-calibrating experimental imperfections in inverse holographic imaging. The technique is demonstrated on auto-focused complex field imaging from a single intensity-only inline hologram. © 2023, CC BY.

关键词： Inverse problems

Learning Photometric Feature Transform for Free-form Object Scan

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arXiv 2023年

作者： Feng, Xiang Kang, Kaizhang Pei, Fan Ding, Huakeng You, Jinjiang Tan, Ping Zhou, Kun Wu, Hongzhi The State Key Lab of CAD & CG Zhejiang University Hangzhou310058 China Department of Electronic and Computer Engineering The Hong Kong University of Science and Technology Hong Kong The Visual Computing Center King Abdullah University of Science and Technology Thuwal23955-6900 Saudi Arabia

We propose a novel framework to automatically learn to aggregate and transform photometric measurements from multiple unstructured views into spatially distinctive and view-invariant low-level features, which are subsequently fed to a multi-view stereo pipeline to enhance 3D reconstruction. The illumination conditions during acquisition and the feature transform are jointly trained on a large amount of synthetic data. We further build a system to reconstruct both the geometry and anisotropic reflectance of a variety of challenging objects from hand-held scans. The effectiveness of the system is demonstrated with a lightweight prototype, consisting of a camera and an array of LEDs, as well as an off-the-shelf tablet. Our results are validated against reconstructions from a professional 3D scanner and photographs, and compare favorably with state-of-the-art techniques. Copyright © 2023, The Authors. All rights reserved.

关键词： Stereo image processing