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Urban Remote Sensing Joint Event

作者： Dimitris Poursanidis Emmanouil Panagiotakis Nektarios Chrysoulakis Remote Sensing Lab Institute of Applied and Computational Mathematics Foundation for Research and Technology Hellas Heraklion Crete Greece

New spaceborne imaging spectrometers will provide great opportunities for mapping urban materials. We use the PRISMA Hyperspectral Imagery to estimate the fractional covers of key urban classes at two levels of details. Impervious, pervious and vegetation at level I where at level II we split the class Impervious to manmade surfaces (cement, asphalt, and metal roofs), the class pervious to soil and non-photosynthetic vegetation (NPV) and the class vegetation into and high and low canopy. The use of Random Forests Regression with synthetically mixed training data generated from the image-based spectral library was used for fraction mapping. Mean Absolute Error for all classes, at both levels, was lower than 18%. All classes at level I achieve error values close to 10% while at level II the majority achieves close to 11% with the lowest (5%) to be for the class "metals" and the highest (17%) to be at the class "soil" which has been overestimated across the urbanscape. We resume that the combination of RFR and synthetically mixed training data generated from the image-based library can allow a generalized urban fraction mapping across various cities of same typology and region when field-based data are absent.

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Competition among the two-plasmon decay of backscattered light,filamentation of the electron-plasma wave and side stimulated Raman scattering

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High Power Laser Science and Engineering 2023年第6期11卷 87-94页

作者： K.Q.Pan Z.C.Li L.Guo T.Gong S.W.Li D.Yang C.Y.Zheng B.H.Zhang X.T.He Laser Fusion Research Center China Academy of Engineering PhysicsMianyangChina Center for Applied Physics and Technology Peking UniversityBeijingChina Institute of Applied Physics and Computational Mathematics BeijingChina

Competition among the two-plasmon decay(TPD)of backscattered light of stimulated Raman scattering(SRS),filamentation of the electron-plasma wave(EPW)and forward side SRS is investigated by two-dimensional particlein-cell *** previous work[*** et al.,*** 58,096035(2018)]showed that in a plasma with the density near 1/10 of the critical density,the backscattered light would excite the TPD,which results in suppression of the backward ***,this work further shows that when the laser intensity is so high(>10^(16)W/cm^(2))that the backward SRS cannot be totally suppressed,filamentation of the EPW and forward side SRS will be *** the TPD of the backscattered light only occurs in the early stage and is suppressed in the latter *** distribution functions further show that trapped-particle-modulation instability should be responsible for filamentation of the *** research can promote the understanding of hot-electron generation and SRS saturation in inertial confinement fusion experiments.

关键词： laser plasma instability inertial confinement fusion high energy density physics particle-in-cell simulation super-hot electrons

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Inverted pin beams for robust propagation through atmospheric turbulence

Inverted pin beams for robust propagation through atmospheri...

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CLEO: Science and Innovations in CLEO 2024, CLEO: S and I 2024 - Part of Conference on Lasers and Electro-Optics

作者： Droulias, Sotiris Loulakis, Michalis Papazoglou, Dimitris G. Tzortzakis, Stelios Chen, Zhigang Efremidis, Nikolaos K. Institute of Applied and Computational Mathematics Foundation for Research and Technology - Hellas Crete Heraklion70013 Greece Department of Digital Systems University of Piraeus Piraeus18534 Greece Institute of Electronic Structure and Laser Foundation for Research and Technology - Hellas P.O. Box 1527 Crete Heraklion71110 Greece Department of Materials Science and Technology University of Crete Crete Heraklion700 13 Greece MOE Key Laboratory of Weak-Light Nonlinear Photonics TEDA Applied Physics Institute School of Physics Nankai University Tianjin300457 China Collaborative Innovation Center of Extreme Optics Shanxi University Shanxi Taiyuan030006 China Department of Applied Mathematics University of Crete Heraklion71409 Greece

We introduce a new class of beams the "inverted pin beams". We show that in atmospheric turbulence inverted pin beams outperform (have reduced scintillations) other classes of beams in moderate to strong flu...

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Inverted pin beams for robust propagation through atmospheric turbulence

Inverted pin beams for robust propagation through atmospheri...

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2024 Conference on Lasers and Electro-Optics, CLEO 2024

ISBN: (纸本)9781957171395

关键词： Laser beams

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Plasticity and melting characteristics of metal Al with Ti-cluster under shock loading

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Chinese Physics B 2021年第7期30卷 200-208页

作者： Dong-Lin Luan Ya-Bin Wang Guo-Meng Li Lei Yuan Jun Chen School of Mechatronic Engineering Beijing Institute of TechnologyBeijing 100081China System Engineering Research Institute Beijing 100094China Beijing Special Vehicle Research Institute Beijing 100072China Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Center for Applied Physics and Technology Peking UniversityBeijing 100871China

Impurity agglomeration has a significant influence on shock response of metal *** this paper,the mechanism of Ti-clusters in metal Al under shock loading is investigated by non-equilibrium molecular dynamics *** results show that the Ti-cluster has obvious effects on the dislocation initiation and melting of bulk ***,the Ti clusters induces the strain concentrate and leads the dislocations to be initiated from the interface of Ti ***,dislocation distribution from the Ti-cluster model results in a formation of a grid-like structure,while the dislocation density is reduced compared with that from the perfect Al ***,the critical shock velocity of dislocation from the Ti-cluster model is lower than from perfect Al ***,it is also found that the temperature near the interface of Ti-cluster is100 K–150 K higher than in the other areas,which means that Ti-cluster interface melts earlier than the bulk area.

关键词： molecular dynamics impurity cluster dislocation shock loading

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Stabilizing oxygen vacancies and promoting electrostrain in leadfree potassium niobate-based piezoelectrics over wide temperature ranges

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Journal of Advanced Ceramics 2024年第12期13卷 1965-1973页

作者： Bingcheng Luo Wei Feng Suwei Dai Hongzhou Song Yunyi Wu Jie Zhang College of Science China Agricultural UniversityBeijing 100083China State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China School of Materials Science and Technology China University of Geosciences BeijingBeijing 100083China Institute of Applied Physics and Computational Mathematics Beijing 100094China Research Center for Comprehensive Energy Technology CTG Science and Technology Research InstituteBeijing 100038China Research Center for Metamaterials Wuzhen LaboratoryJiaxing 314500China

Piezoelectric ceramics provide high strain and large driving forces in actuators.A large electrostrain can be realized by the introduction of point defects such as vacancies,interstitial defects,and substitution *** Mn doping,a significant increase in the reversible electrostrain from 0.05%to 0.17%could be achieved in potassium niobite lead-free piezoelectric *** origins of the large electrostrain were analyzed via in situ X-ray diffraction(XRD)under an electric *** electrostrain and other typical electrical properties of the samples were measured at various temperatures,which enabled the ceramics to perform under a very wide temperature range,such as−80–130℃ for the 0.5 mol%Mn-doped sample with low dielectric loss(≤0.02).More importantly,combined with characterizations of the defect behavior by thermally stimulated depolarization current(TSDC),the failure mechanisms of electrostrain in a hightemperature environment could be revealed,which was associated with synergistic damage to the defects caused by the electric field and high *** results can provide good ideas and a basis for the design of piezoelectric materials with good electrostrain stability over a wide temperature range.

关键词： piezoelectric ceramic lead-free point defect electrostrain thermally stimulated depolarization current(TSDC)

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Detecting and Exploiting Unit Commitment Structures in MIPs 6

Detecting and Exploiting Unit Commitment Structures in MIPs

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6th International Conference on Power and Energy technology, ICPET 2024

作者： Su, Zhao-Gang Chen, Sheng-Jie Li, Yu-Fei Chen, Liang Kou, Caixia Cai, Zhi Institute of Computational Mathematics and Scientific/Engineering Computing Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China Institute of Applied Mathematics Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China College of Sciences Beijing University of Posts and Telecommunications Beijing China Beijing Key Laboratory of Research and System Evaluation of Power Dispatching Automation Technology China Electric Power Research Institute Beijing China

ISBN: (纸本)9798350375855

The unit commitment (UC) problem has been extensively researched in the literature, which is typically formulated as a mixed integer programming (MIP) problem. However, current studies lack effective methods to identify potential UC problem structures within a general MIP problem, making it challenging to leverage well-established valid inequalities for UC problems to accelerate the solution process. In this paper, we present a novel detection method that automatically identifies UC structures within an MIP problem by analyzing the relationships between variables and constraints. Moreover, we enhance the MIP formulation by incorporating three well-studied classes of valid inequalities as cutting planes, based on the identified UC structures. Our experiments demonstrate that our proposed UC detection method greatly improves computational efficacy of a standard MIP solver compared to the default setting. © 2024 IEEE.

关键词： Mixed-integer linear programming

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Molecule opacity study on low-lying states of CS

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Chinese Physics B 2022年第10期31卷 362-370页

作者： Rui Li Jiqun Sang Xiaohe Lin Jianjun Li Guiying Liang Yong Wu Department of Physics College of ScienceQiqihar UniversityQiqihar 161006China National Key Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China Faculty of Foundation Space Engineering UniversityBeijing 101416China School of Data Science and Artificial Intelligence Jilin Engineering Normal UniversityChangchun 130052China HEDPS Center for Applied Physics and TechnologyPeking UniversityBeijing 100084China

CS molecule, which plays a key role in atmospheric and astrophysical circumstances, has drawn great attention for long time. Owing to its large state density, the detailed information of the electronic structure of CS is still lacking. In this work, the high-level MRCI+Q method is used to compute the potential energy curves, dipole moments and transition dipole moments of singlet and triplet states correlated with the lowest dissociation limit of CS, based on which high accurate vibration-rotation levels and spectroscopic constants of bound states are evaluated. The opacity of CS relevant to atmospheric circumstance is computed at a pressure of 100 atms for different temperatures. With the increase of temperature,band systems from different transitions mingle with each other, and band boundaries become blurred, which are originated from the increased population on vibrational excited states and electronic excited states at high temperature.

关键词： CS transition dipole moment opacity excited state

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A POSTERIORI CERTIFICATION FOR PHYSICS-INFORMED NEURAL NETWORKS

arXiv

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arXiv 2025年

作者： Ernst, Lewin Rekatsinas, Nikolaos Urban, Karsten Institute for Numerical Mathematics Ulm University Helmholtzstr. 20 Ulm89081 Germany Institute of Applied and Computational Mathematics Foundation of Research and Technology Nikolaou Plastira 100 Vassilika Vouton Crete HeraklionGR 70013 Greece

We propose rigorous lower and upper bounds for a PINN approximation to PDEs by efficiently computing the Riesz representations of suitable extension and restrictions of the PINN residual towards geometrically simpler domains, which are either embedded or enveloping the original domain. Error bounds are proven and detailed for elliptic as well as parabolic problems. Numerical experiments show the good quantitative behaviour of the derived upper and lower error *** Codes 35J20, 65M15, 68T07 Copyright © 2025, The Authors. All rights reserved.

关键词： Partial differential equations

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Application of a p-version curved C^(1)finite element based on the nonlocal Kirchhoff plate theory to the vibration analysis of irregularly shaped nanoplates

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Science China(Technological Sciences) 2023年第10期66卷 3025-3047页

作者： XIANG Wei NI Hua TIAN YiFeng WU Yang LIU Bo School of Mechanical Engineering Southwest Jiaotong UniversityChengdu 610031China Technology and Equipment of Rail Transit Operation and Maintenance Key Laboratory of Sichuan Province Chengdu 610031China Southwest China Research Institute of Electronic Equipment Chengdu 610036China CAEP Software Center for High Performance Numerical Simulation Beijing 100088China Institute of Applied Physics and Computational Mathematics Beijing 100088China The Solid Mechanics Research Centre Beihang University(BUAA)Beijing 100191China

Nanoplates have been widely used as elementary components for ultrasensitive and ultrafine resolution applications in the field of nano-electro-mechanical systems because of their potentially remarkable mechanical *** accurate analysis of their mechanical behavior is currently of particular interest in the function design and reliability analysis of nano-scaled *** examine the size-dependent bending and vibration behavior of nanoplates with curvilinear and irregular shapes,a new p-version curved C^(1)finite element is formulated in the framework of the nonlocal Kirchhoff plate *** newly developed element not only enables an accurate geometry representation and easy mesh generation of curvilinear domains but also overcomes the difficulty of imposing C^(1)conformity required by the nonlocal Kirchhoff plate model,particularly on the curvilinear inter-element *** examples show that this element can produce an exponential rate of convergence even when curved elements are used in the domain *** numerical results are presented for nanoplates with various geometric shapes,including rectangular,circular,elliptic,annular,and *** high accuracy of the present element is verified by comparing the obtained results with analytical and numerical results in the ***,a comprehensive parametric analysis is conducted to investigate the influences of nonlocal parameters,plate dimensions,and boundary conditions on the nonlocal behavior of *** present element can be envisaged to allow large-scale mechanical simulations of nanoplates,with a guarantee of accuracy and efficiency.

关键词： nanoplates nonlocal theory p-version finite element method C^(1)conformity irregular shape

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