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IEEE Conference on Vehicular Technology (VTC)

作者： Tamer E. Fahim Sherif I. Rabia Ahmed H. Abd El-Malek Waheed K. Zahra Institute of Basic and Applied Sciences Egypt-Japan University of Science and Technology (E-JUST) Alexandria Egypt Department of Engineering Mathematics and Physics Faculty of Engineering Alexandria University Alexandria Egypt Department of Electronics and Communications Engineering Egypt-Japan University of Science and Technology (E-JUST) Alexandria Egypt Department of Engineering Physics and Mathematics Faculty of Engineering Tanta University Tanta Egypt

ISBN: (数字)9798331517786

ISBN: (纸本)9798331517793

Currently, the pervasive adoption of internet of things technology sheds light on the significance of real-time status update systems. The age of information (AoI) metric has been devised to reflect the strict information timeliness of such systems. Bufferless packet management scheme has demonstrated higher effectiveness in the AoI minimization. However, the existing preemptive (PR) and non-preemptive (NP) service disciplines operate independently of the system state, thereby reducing the system’s adaptability to varying system parameter settings, such as service time distribution and traffic loading condition. Therefore, we propose an elapsed-time-based hybrid PR/NP discipline to govern the service preemptions in a single-source M/Er/1/1 queueing scheme. The preemption is declined when the elapsed service time surpasses a predetermined threshold (controlling parameter). The average AoI is analyzed using the stochastic hybrid system approach. The numerical study demonstrated that the proposed discipline, owing to its threshold parameter, fulfills the optimality of the AoI performance, especially under highly dispersed Erlang service time distributions and higher traffic loading conditions.

关键词： Measurement Vehicular and wireless technologies Loading Stochastic processes Performance gain Information age Minimization Real-time systems Time factors Optimization

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Electronic properties of 2D materials and their junctions

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Nano Materials science 2024年第1期6卷 1-23页

作者： Taposhree Dutta Neha Yadav Yongling Wu Gary J.Cheng Xiu Liang Seeram Ramakrishna Aoussaj Sbai Rajeev Gupta Aniruddha Mondal Zheng Hongyu Ashish Yadav Department of Chemistry Indian Institute of Engineering Science and TechnologyShibpurWest Bengal711103India Center for Advanced Laser Manufacturing(CALM) Shandong University of TechnologyZibo255000PR China School of Industrial Engineering Purdue University315 N.Grant St.West LafayetteIN47907United States Birck Nanotechnology Center Purdue University1205 W State St.West LafayetteIN47907United States Advanced Materials Institute Qilu University of TechnologyShandong Academy of SciencesJinan250014PR China Nanoscience and Nanotechnology Initiative National University of Singapore10 Kent Ridge Crescent119260Singapore Faculty of Applied Phsyics and Mathematics Gdansk University of Technology Narutowicza 11/1280233GdanskPoland Department of Physics School of EngineeringUniversity of Petroleum&Energy StudiesDehradun248007UttarakhandIndia Department of Physics National Institute of Technology DurgapurDurgapur713209West BengalIndia

With an extensive range of distinctive features at nano meter-scale thicknesses,two-dimensional(2D)materials drawn the attention of the scientific *** tremendous advancements in exploratory research on 2D materials,knowledge of 2D electrical transport and carrier dynamics still in its ***,here we highlighted the electrical characteristics of 2D materials with electronic band structure,electronic transport,dielectric constant,carriers *** atomic thinness of 2D materials makes substantially scaled field-effect transistors(FETs)with reduced short-channel effects conceivable,even though strong carrier mobility required for high performance,low-voltage device *** also discussed here about factors affecting 2D materials which easily enhanced the activity of those materials for various ***,Those 2D materials used in state-of-the-art electrical and optoelectronic devices because of the extensive nature of their electronic band structure.2D materials offer unprecedented freedom for the design of novel p-n junction device topologies in contrast to conventional bulk *** also,describe the numerous 2D p-n junctions,such as homo junction and hetero junction including mixed dimensional ***,we talked about the problems and potential for the future.

关键词： 2D materials Electrical properties p-n junctions Mixed hereto junctions Homo junctions Electrical transport

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Learning the solution operator of two-dimensional incompressible Navier-Stokes equations using physics-aware convolutional neural networks

arXiv

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arXiv 2023年

作者： Grimm, Viktor Heinlein, Alexander Klawonn, Axel Department of Mathematics and Computer Science University of Cologne Weyertal 86-90 Köln50931 Germany Center for Data and Simulation Science University of Cologne Köln50923 Germany Delft Institute of Applied Mathematics Delft University of Technology Mekelweg 4 Delft2628 CD Netherlands

In recent years, the concept of introducing physics to machine learning has become widely popular. Most physics-inclusive ML-techniques however are still limited to a single geometry or a set of parametrizable geometries. Thus, there remains the need to train a new model for a new geometry, even if it is only slightly modified. With this work we introduce a technique with which it is possible to learn approximate solutions to the steady-state Navier–Stokes equations in varying geometries without the need of parametrization. This technique is based on a combination of a U-Net-like CNN and well established discretization methods from the field of the finite difference method. The results of our physics-aware CNN are compared to a state-of-the-art data-based approach. Additionally, it is also shown how our approach performs when combined with the data-based *** Codes 35Q30, 68T07, 68T10, 65N22 Copyright © 2023, The Authors. All rights reserved.

关键词： Machine learning

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An Asymptotic-Preserving Method for the Three-Temperature Radiative Transfer Model

SSRN

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SSRN 2024年

作者： Li, Ruo Li, Weiming Liang, Shengtong Shao, Yuehan Tang, Min Wang, Yanli CAPT LMAM School of Mathematical Sciences Peking University Beijing China Institute of Applied Physics and Computational Mathematics Beijing China School of Mathematical Sciences Peking University Beijing China Institute of Natural Sciences School of Mathematics Shanghai Jiaotong University Shanghai China Beijing Computational Science Research Center Beijing China

We present an asymptotic-preserving (AP) numerical method for solving the three-temperature radiative transfer model, which holds significant importance in inertial confinement fusion. A carefully designed splitting method is developed that can provide a general framework of the extending AP schemes for the gray radiative transport equation to the more complex three-temperature radiative transfer model. The proposed scheme captures two important limiting models: the three-temperature radiation diffusion equation (3TRDE) when opacity approaches infinity and the two-temperature limit when the ion-electron coupling coefficient goes to infinity. We have rigorously demonstrated the AP property and energy conservation characteristics of the proposed scheme and its efficiency has been validated through a series of benchmark tests in the numerical part. © 2024, The Authors. All rights reserved.

关键词： Radiative transfer

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Organic room-temperature polariton condensate in a higher-order topological lattice

arXiv

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arXiv 2024年

作者： Bennenhei, Christoph Shan, Hangyong Struve, Marti Kunte, Nils Eilenberger, Falk Ohmer, Jürgen Fischer, Utz Schumacher, Stefan Ma, Xuekai Schneider, Christian Esmann, Martin Institute of Physics School of Mathematics and Science Carl von Ossietzky Universität Oldenburg Oldenburg26129 Germany Institute of Applied Physics Abbe Center of Photonics Friedrich Schiller University Jena Jena07743 Germany Fraunhofer-Institute for Applied Optics and Precision Engineering IOF Jena07743 Germany Max-Planck-School of Photonics Jena07743 Germany Department of Biochemistry University of Würzburg Würzburg97074 Germany Paderborn University Paderborn33098 Germany

Organic molecule exciton-polaritons in photonic lattices are a versatile platform to emulate unconventional phases of matter at ambient conditions, including protected interface modes in topological insulators. Here, we investigate bosonic condensation in the most prototypical higher-order topological lattice: a 2D-version of the Su-Schrieffer-Heeger (SSH) model, supporting both 0D and 1D topological modes. We study fluorescent protein-filled, structured microcavities defining a staggered photonic trapping potential and observe the resulting first- and higher-order topologically protected modes via spatially resolved photoluminescence spectroscopy. We account for the spatial mode patterns by tight-binding calculations and theoretically characterize the topological invariants of the lattice. Under strong optical pumping, we observe bosonic condensation into the topological modes. Via interferometric measurements, we map the spatial first-order coherence in the protected 1D modes extending over 10µm. Our findings pave the way towards organic on-chip polaritonics using higher-order topology as a tool for the generation of robustly confined polaritonic lasing states. Copyright © 2024, The Authors. All rights reserved.

关键词： Microcavities

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An asymptotic-preserving method for the three-temperature radiative transfer model

arXiv

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arXiv 2024年

作者： Li, Ruo Li, Weiming Liang, Shengtong Shao, Yuehan Tang, Min Wang, Yanli CAPT LMAM & School of Mathematical Sciences Peking University Beijing China Institute of Applied Physics and Computational Mathematics Beijing China School of Mathematical Sciences Peking University Beijing China Institute of Natural Sciences School of Mathematics Shanghai Jiaotong University Shanghai China Beijing Computational Science Research Center Beijing China

We present an asymptotic-preserving (AP) numerical method for solving the three-temperature radiative transfer model, which holds significant importance in inertial confinement fusion. A carefully designed splitting method is developed that can provide a general framework of extending AP schemes for the gray radiative transport equation to the more complex three-temperature radiative transfer model. The proposed scheme captures two important limiting models: the three-temperature radiation diffusion equation (3TRDE) when opacity approaches infinity and the two-temperature limit when the ion-electron coupling coefficient goes to infinity. We have rigorously demonstrated the AP property and energy conservation characteristics of the proposed scheme and its efficiency has been validated through a series of benchmark tests in the numerical part. © 2024, CC0.

关键词： Radiative transfer

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Ab initio study on the stability and elasticity of brucite

arXiv

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arXiv 2023年

作者： Wang, Hongjin Luo, Chenxing Wentzcovitch, Renata M. Department of Applied Physics and Applied Mathematics Columbia University New YorkNY10027 United States Department of Earth and Environmental Sciences Columbia University New YorkNY10027 United States Lamont–Doherty Earth Observatory Columbia University PalisadesNY10964 United States Data Science Institute Columbia University New YorkNY10027 United States

Brucite (Mg(OH)2) is a mineral of great interest owing to its various applications and roles in geological processes. Its structure, behavior under different conditions, and unique properties have been the subject of numerous studies and persistent debate. As a stable hydrous phase in subduction zones, its elastic anisotropy can significantly contribute to the seismological properties of these regions. We performed ab initio calculations to investigate brucite’s stability, elasticity, and acoustic velocities. We tested several exchange-correlation functionals and managed to obtain stable phonons for the P3¯ phase with r2SCAN for the first time at all relevant pressures up to the mantle transition zone. We show that r2SCAN performs very well in brucite, reproducing the experimental equation of state and several key structure parameters related to hydrogen positions. The room temperature elasticity results in P3¯ reproduces the experimental results at ambient pressure. These results, together with the stable phonon dispersion of P3¯ at all relevant pressures, indicate P3¯ is the stable candidate phase not only at elevated pressures but also at ambient conditions. The success of r2SCAN in brucite, suggests this functional should be suitable for other challenging layer-structured minerals, e.g., serpentines, of great geophysical significance. Copyright © 2023, The Authors. All rights reserved.

关键词： Elasticity

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Predicting Ground State Properties: Constant Sample Complexity and Deep Learning Algorithms

arXiv

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arXiv 2024年

作者： Wanner, Marc Lewis, Laura Bhattacharyya, Chiranjib Dubhashi, Devdatt Gheorghiu, Alexandru Department of Computer Science and Engineering Chalmers University of Technology University of Gothenburg Gothenburg Sweden Department of Applied Mathematics and Theoretical Physics University of Cambridge Cambridge United Kingdom Department of Computer Science and Automation Indian Institute of Science Bangalore India Department of Computer Science and Engineering Chalmers University of Technology Gothenburg Sweden

A fundamental problem in quantum many-body physics is that of finding ground states of local Hamiltonians. A number of recent works gave provably efficient machine learning (ML) algorithms for learning ground states. Specifically, Huang et al. in [1], introduced an approach for learning properties of the ground state of an n-qubit gapped local Hamiltonian H from only nO(1) data points sampled from Hamiltonians in the same phase of matter. This was subsequently improved by Lewis et al. in [2], to O(log n) samples when the geometry of the n-qubit system is known. In this work, we introduce two approaches that achieve a constant sample complexity, independent of system size n, for learning ground state properties. Our first algorithm consists of a simple modification of the ML model used by Lewis et al. and applies to a property of interest known in advance. Our second algorithm, which applies even if a description of the property is not known, is a deep neural network model. While empirical results showing the performance of neural networks have been demonstrated, to our knowledge, this is the first rigorous sample complexity bound on a neural network model for predicting ground state properties. We also perform numerical experiments on systems of up to 45 qubits that confirm the improved scaling of our approach compared to [1, 2]. © 2024, CC BY.

关键词： Qubits

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Periodic Normal Forms for Bifurcations of Limit Cycles in DDEs

arXiv

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arXiv 2023年

作者： Lentjes, Bram Spek, Len Bosschaert, Maikel M. Kuznetsov, Yuri A. Department of Mathematics Hasselt University Diepenbeek Campus Diepenbeek3590 Belgium Department of Applied Mathematics University of Twente Enschede7500 AE Netherlands Data Science Institute Hasselt University Diepenbeek Campus Diepenbeek3590 Belgium Department of Mathematics Utrecht University Utrecht3508 TA Netherlands

A recent work [39] by the authors on the existence of a periodic smooth finite-dimensional center manifold near a nonhyperbolic cycle in delay differential equations motivates the derivation of periodic normal forms. In this paper, we prove the existence of a special coordinate system on the center manifold that will allow us to describe the local dynamics on the center manifold near the cycle in terms of these periodic normal forms. To construct the linear part of this coordinate system, we prove the existence of time periodic smooth Jordan chains for the original and adjoint system. Moreover, we establish duality and spectral relations between both systems by using tools from the theory of delay equations and Volterra integral equations, dual perturbation theory, duality theory and evolution *** Codes 34C20, 34K13, 34K17, 34K18, 34K19 © 2023, CC BY.

关键词： Differential equations

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Critical latitude in global quasi-geostrophic flow on a rotating sphere

arXiv

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arXiv 2024年

作者： Franken, Arnout D. Luesink, Erwin Ephrati, Sagy R. Geurts, Bernard J. Mathematics of Multiscale Modelling and Simulation Department of Applied Mathematics Faculty EEMCS University of Twente PO Box 217 Enschede7500 AE Netherlands Korteweg-de-Vries Institute University of Amsterdam PO Box 94248 Science Park 107 Amsterdam1090 GE Netherlands Department of Mathematical Sciences Chalmers University of Technology Gothenburg412 96 Sweden Multiscale Physics Center for Computational Energy Research Department of Applied Physics Eindhoven University of Technology Eindhoven Netherlands

In this paper, we study geostrophic turbulence without external forcing or dissipation, using a Casimir-preserving numerical method. The research examines the formation of large zonal jets, common in geophysical flows, especially in giant gas planets. These jets form due to the east-west stretching of vortices, influenced by the gradient of the Coriolis parameter, leading to a critical latitude beyond which jets do not form. Using a global quasi-geostrophic model with a fully latitude-dependent Coriolis parameter, we investigate this critical latitude, which is theorized to depend only on the product of the Rossby number and the Lamb parameter. By simulating random flow fields, the critical latitude was identified through zonally averaged zonal velocity profiles. Results align with geostrophic theory, especially near typical Rossby and Lamb parameter values for Earth’s atmosphere. However, in the regime of weak rotation (high Rossby numbers) and strong stratification (high Lamb values), no clear critical latitude emerges;instead, zonal jet amplitude and width decrease gradually towards the poles. This research paves the way for further study of jet dynamics under a fully latitude-dependent Coriolis parameter. Copyright © 2024, The Authors. All rights reserved.

关键词： Miocene

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