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Progress in Electromagnetic Research Symposium (PIERS)

作者： Ping Li Yifei Shi Hakan Bagci Department of Electrical and Computer Engineering Purdue University West Lafayette IN USA Division of Computer Electrical and Mathematical Sciences and Engineering King Abdullah University of Science and Technology (KAUST) Saudi Arabia Center for Uncertainty Quantification in Computational Science and Engineering King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia

ISBN: (纸本)9781509060948

Summary form only given. The discontinuous Galerkin time-domain (DGTD) method is gaining popularity among computational electromagnetics (CEM) practitioners. This can be attributed to the fact that it has several advantages over the classical finite element method. The DGTD method realizes “information exchange” between neighboring spatial discretization elements using numerical flux. Therefore all spatial operations are localized within a given element leading to a block-diagonal mass matrix which is inverted very efficiently only once before the time marching starts. Consequently, if an explicit time integrator is used, the DGTD method becomes high compact and efficient. Despite these advantages, the use of the DGTD method for analyzing electromagnetic field interactions on microwave systems loaded with cables/thin wires has been very limited. Direct application of the DGTD method for solving Maxwell equation on such structures will result in a rather inefficient simulation tool since the DGTD will call for a very fine discretization in the proximity of thin wires. To overcome this problem, in this work, electromagnetic field interactions on thin wires are modeled using the modified telegrapher's equation (MTEs), which describe a simplified relation between transient voltage and current distributions along a given thin wire. Like Maxwell equations, MTEs describes a hyperbolic system of equations, which are discretized using the one-dimensional (1D) DGTD method. The coupling between the two matrix systems resulting from the discretization of Maxwell equations and MTEs using 3D and 1D DGTD methods is realized by introducing equivalent source terms in each equation set. A weighted electric field obtained from the 3D discretization around the wire is introduced as a voltage source in the MTEs. A volume current density obtained from the 1D discretization on the wire is introduced as a current source in the Maxwell equation describing the Ampere's law equation, respecti

关键词： Wires Mathematical model Electromagnetics Microwave theory and techniques STEM Maxwell equations Three-dimensional displays

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Euclid preparation: II. The EuclidEmulator – A tool to compute the cosmology dependence of the nonlinear matter power spectrum

arXiv

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arXiv 2018年

作者： Knabenhans, Mischa Stadel, Joachim Marelli, Stefano Potter, Doug Teyssier, Romain Legrand, Laurent Schneider, Aurel Sudret, Bruno Blot, Linda Awan, Saeeda Burigana, Carlo Carvalho, Carla Sofia Kurki-Suonio, Hannu Sirri, Gabriele Institute for Computational Science University of Zurich Winterthurerstrasse 190 Zurich8057 Switzerland Chair of Risk Safety and Uncertainty Quantification Dept. of Civil Engineering ETH Zurich Stefano-Franscini-Platz 5 Zurich8093 Switzerland Kapteyn Astronomical Institute University of Groningen Landleven 12 Groningen9747 Netherlands Institute for Particle Physics and Astrophysics Dept. of Physics ETH Zurich Wolfgang-Pauli-Strasse 27 Zurich8093 Switzerland Campus UAB Carrer de Can Magrans s/n Barcelona08193 Spain Barcelona08034 Spain Mullard Space Science Laboratory University College London Holmbury St. Mary DorkingRH5 6NT United Kingdom INAF Istituto di Radioastronomia Via Piero Gobetti 101 BolognaI-40129 Italy Dipartimento di Fisica e Scienze della Terra Università di Ferrara Via Giuseppe Saragat 1 FerraraI-44122 Italy Istituto Nazionale di Fisica Nucleare Sezione di Bologna Via Irnerio 46 BolognaI-40126 Italy Instituto de Astrofísica e Ciências do Espaço Faculdade de Ciências Universidade de Lisboa Tapada da Ajuda LisboaPT-1349-018 Portugal Department of Physics Helsinki Institute of Physics University of Helsinki Gustaf Hällströmin katu 2 00014 Finland INFN - Bologna Istituto Nazionale di Fisica Nucleare V.le Berti Pichat 6/2 Bologna40127 Italy

We present a new power spectrum emulator named EuclidEmulator that estimates the nonlinear correction to the linear dark matter power spectrum depending on the six cosmological parameters ωb, ωm, ns, h, w0 and σ8. It is constructed using the uncertainty quantification software UQLab using a spectral decomposition method called polynomial chaos expansion. All steps in its construction have been tested and optimized: the large high-resolution N-body simulations carried out with PKDGRAV3 were validated using a simulation from the Euclid Flagship campaign and demonstrated to have converged up to wavenumbers k ≈ 5 hMpc−1 for redshifts z ≤ 5. The emulator is based on 100 input cosmologies simulated in boxes of (1250Mpc/h)3 using 20483 particles. We show that by creating mock emulators it is possible to successfully predict and optimize the performance of the final emulator prior to performing any N-body simulations. The absolute accuracy of the final nonlinear power spectrum is as good as one obtained with N-body simulations, conservatively, ∼ 1% for k . 1 hMpc−1 and z . 1. This enables efficient forward modeling in the nonlinear regime allowing for estimation of cosmological parameters using Markov Chain Monte Carlo (MCMC) methods. EuclidEmulator has been compared to HALOFIT, CosmicEmu and NGenHalofit, and shown to be more accurate than these other approaches. This work paves a new way for optimal construction of future emulators that also consider other cosmological observables, use higher resolution input simulations and investigate higher dimensional cosmological parameter spaces. Copyright © 2018, The Authors. All rights reserved.

关键词： Cosmology

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A stochastic maximum principle for risk-sensitive mean-field type control

A stochastic maximum principle for risk-sensitive mean-field...

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作者： Djehiche, Boualem Tembine, Hamidou Tempone, Raul Department of Mathematics KTH Royal Institute of Technology Stockholm100 44 Sweden Center for Interdisciplinary Studies in Security and Privacy Electrical and Computer Engineering Polytechnic School of Engineering New York University NY10003 United States Division of Engineering Saadiyat Island New York University Abu Dhabi Abu Dhabi United Arab Emirates SRI Uncertainty Quantification Center in Computational Science and Engineering CEMSE King Abdullah University of Science and Technology Thuwai Jeddah23955-6900 Saudi Arabia

In this paper we study mean-field type control problems with risk-sensitive performance functionals. We establish a stochastic maximum principle (SMP) for optimal control of stochastic differential equations (SDEs) of mean-field type, in which the drift and the diffusion coefficients as well as the performance functional depend not only on the state and the control but also on the mean of the distribution of the state. Our result extends the risk-sensitive SMP (without mean-field coupling) of Lim and Zhou (2005), derived for feedback (or Markov) type optimal controls, to optimal control problems for non-Markovian dynamics which may be time-inconsistent in the sense that the Bellman optimality principle does not hold. In our approach to the risk-sensitive SMP, the smoothness assumption on the value-function imposed in Lim and Zhou (2005) needs not be satisfied. For a general action space a Peng's type SMP is derived, specifying the necessary conditions for optimality. Two examples are carried out to illustrate the proposed risk-sensitive mean-field type SMP under linear stochastic dynamics with exponential quadratic cost function. Explicit solutions are given for both mean-field free and mean-field models. © 1963-2012 IEEE.

关键词： Maximum principle

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Exponential stability of shallow water equations with arbitrary time dependent action

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International Journal of Dynamics and Control 2014年第3期2卷 247-253页

作者： Dia, Ben Mansour SRI Center for Uncertainty Quantification in Computational Science and Engineering CEMSE King Abdullah University of Sciences and Technology Thuwal23955-6900 Saudi Arabia

In this paper, we examine an exponential stability result in L2- norm of the classical solution of shallow water equations. By using Riemann analysis with sub-critical flow condition, we show that only one boundary control law suffices to achieve the exponential stability. For that, we provide a sufficient dissipative condition as second order polynomial inequality with respect to the boundary control law which relies on the setting of a non-increasing arbitrary action. © 2014, Springer-Verlag Berlin Heidelberg.

关键词： Equations of motion

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Nonasymptotic mean-field games 19

Nonasymptotic mean-field games

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19th IFAC World Congress on International Federation of Automatic Control, IFAC 2014

作者： Tembine, Hamidou KAUST Strategic Research Initiative Center for Uncertainty Quantification in Computational Science and Engineering CEMSE KAUST Saudi Arabia

ISBN: (纸本)9783902823625

Mean-field games have been studied under the assumption of very large number of players. For such large systems, the basic idea consists to approximate large games by a stylized game model with a continuum of players. The approach has been shown to be useful in some applications. However, the stylized game model with continuum of decision-makers is rarely observed in practice and the approximation proposed in the asymptotic regime is meaningless for networked systems with few entities. In this paper we propose a mean-field framework that is suitable not only for large systems but also for a small world with few number of entities. The applicability of the proposed framework is illustrated through a dynamic auction with asymmetric valuation distributions. © IFAC.

关键词： Game theory

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Fast distributed strategic learning for global optima in queueing access games 19

Fast distributed strategic learning for global optima in que...

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19th IFAC World Congress on International Federation of Automatic Control, IFAC 2014

作者： Tembine, Hamidou KAUST Strategic Research Initiative Center for Uncertainty Quantification in Computational Science and Engineering CEMSE KAUST Saudi Arabia

ISBN: (纸本)9783902823625

In this paper we examine combined fully distributed payoff and strategy learning (CODIPAS) in a queue-aware access game over a graph. The classical strategic learning analysis relies on vanishing or small learning rate and uses stochastic approximation tool to derive steady states and invariant sets of the underlying learning process. Here, the stochastic approximation framework does not apply due to non-vanishing learning rate. We propose a direct proof of convergence of the process. Interestingly, the convergence time to one of the global optima is almost surely finite and we explicitly characterize the convergence time. We show that pursuit-based CODIPAS learning is much faster than the classical learning algorithms in games. We extend the methodology to coalitional learning and proves a very fast formation of coalitions for queue-aware access games where the action space is dynamically changing depending on the location of the user over a graph. © IFAC.

关键词： Learning algorithms

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Cooperative mean-field type games 19

Cooperative mean-field type games

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19th IFAC World Congress on International Federation of Automatic Control, IFAC 2014

作者： Cissé, Abdoul Karim Tembine, Hamidou GrIIsG - ISG International Business School Paris France SRI - Center for Uncertainty Quantification in Computational Science and Engineering CEMSE KAUST Saudi Arabia

ISBN: (纸本)9783902823625

In the standard formulation of a game, a player's payoff function depends on the states and actions of all the players. Yet, real world applications suggest to consider also a functional of the probability measure of states and actions of all the players. In this paper, we consider cooperative mean-field type games in which the state dynamics and the payoffs depend not only on the state and actions but also on their probability measure. We establish stochastic maximum principle and provide a time-dependent payoff allocation procedure for coalitions. The allocated payoff considers not only fairness property but also the cost of making the coalition. Finally, time consistency and subgame perfectness solution concept equations are established. © IFAC.

关键词： Stochastic systems

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Euclid preparation: IX. EuclidEmulator2 – Power spectrum emulation with massive neutrinos and self-consistent dark energy perturbations

arXiv

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arXiv 2020年

作者： Knabenhansz, M. Stadel, J. Potter, D. Dakin, J. Hannestad, S. Tram, T. Marelli, S. Schneider, A. Teyssier, R. Andreon, S. Auricchio, N. Baccigalupi, C. Balaguera-Antolínez, A. Baldi, M. Bardelli, S. Battaglia, P. Bender, R. Biviano, A. Bodendorf, C. Bozzo, E. Branchini, E. Brescia, M. Burigana, C. Cabanac, R. Camera, S. Capobianco, V. Cappi, A. Carbone, C. Carretero, J. Carvalho, C.S. Casas, R. Casas, S. Castellano, M. Castignani, G. Cavuoti, S. Cledassou, R. Colodro-Conde, C. Congedo, G. Conselice, C.J. Conversi, L. Copin, Y. Corcione, L. Coupon, J. Courtois, H.M. da Silva, A. de la Torre, S. Di Ferdinando, D. Duncan, C.A.J. Dupac, X. Fabbian, G. Farrens, S. Ferreira, P.G. Finelli, F. Frailis, M. Franceschi, E. Galeotta, S. Garilli, B. Giocoli, C. Gozaliasl, G. Graciá-Carpio, J. Grupp, F. Guzzo, L. Holmes, W. Hormuth, F. Israel, H. Jahnke, K. Keihanen, E. Kermiche, S. Kirkpatrick, C.C. Kubik, B. Kunz, M. Kurki-Suonio, H. Ligori, S. Lilje, P.B. Lloro, I. Maino, D. Marggraf, O. Markovic, K. Martinet, N. Marulli, F. Massey, R. Mauri, N. Maurogordato, S. Medinaceli, E. Meneghetti, M. Metcalf, B. Meylan, G. Moresco, M. Morin, B. Moscardini, L. Munari, E. Neissner, C. Niemi, S.M. Padilla, C. Paltani, S. Pasian, F. Patrizii, L. Pettorino, V. Pires, S. Polenta, G. Poncet, M. Raison, F. Renzi, A. Rhodes, J. Riccio, G. Romelli, E. Roncarelli, M. Saglia, R. Sánchez, A.G. Sapone, D. Schneider, P. Scottez, V. Secroun, A. Serrano, S. Sirignano, C. Sirri, G. Stanco, L. Sureau, F. Tallada Crespí, P. Taylor, A.N. Tenti, M. Tereno, I. Toledo-Moreo, R. Torradeflot, F. Valenziano, L. Valiviita, J. Vassallo, T. Viel, M. Wang, Y. Welikala, N. Whittaker, L. Zacchei, A. Zucca, E. Institute for Computational Science University of Zurich Winterthurerstrasse 190 Zurich8057 Switzerland Department of Physics and Astronomy University of Aarhus Ny Munkegade 120 Aarhus CDK-8000 Denmark Risk Safety and Uncertainty Quantification Dept. of Civil Engineering ETH Zurich Stefano-Franscini-Platz 5 Zurich8093 Switzerland Institute for Particle Physics and Astrophysics Dept. of Physics ETH Zurich Wolfgang-Pauli-Strasse 27 Zurich8093 Switzerland INAF-Osservatorio Astronomico di Brera via Brera 28 MilanoI-20122 Italy INAF-Osservatorio di Astrofisica e Scienza dello Spazio di Bologna via Piero Gobetti 93/3 BolognaI-40129 Italy SISSA International School for Advanced Studies via Bonomea 265 Trieste TSI-34136 Italy INFN Sezione di Trieste via Valerio 2 Trieste TSI-34127 Italy INAF-Osservatorio Astronomico di Trieste via G. B. Tiepolo 11 TriesteI-34131 Italy Universidad de la Laguna E-38206 San Cristóbal de La Laguna Tenerife Spain Instituto de Astrofísica de Canarias Calle vía Làctea s/n San Cristóbal de la Laguna Tenerife38204 Spain via Gobetti 93/3 BolognaI-40127 Italy Dipartimento di Fisica e Astronomia Universitá di Bologna via Gobetti 93/2 BolognaI-40129 Italy INFN-Sezione di Bologna viale Berti Pichat 6/2 BolognaI-40127 Italy INAF-IASF Bologna via Piero Gobetti 101 BolognaI-40129 Italy Universitäts-Sternwarte München Fakultät für Physik Ludwig-Maximilians-Universität München Scheinerstrasse 1 München81679 Germany Max Planck Institute for Extraterrestrial Physics Giessenbachstr. 1 GarchingD-85748 Germany IFPU Institute for Fundamental Physics of the Universe via Beirut 2 Trieste34151 Italy Department of Astronomy University of Geneva ch. d’Écogia 16 VersoixCH-1290 Switzerland INFN-Sezione di Roma Tre via della Vasca Navale 84 RomaI-00146 Italy Department of Mathematics and Physics Roma Tre University via della Vasca Navale 84 RomeI-00146 Italy INAF-Osservatorio Astronomico di Roma via Frascati 33 Montepo

We present a new, updated version of the EuclidEmulator (called EuclidEmulator2), a fast and accurate predictor for the nonlinear correction of the matter power spectrum. Percent-level accurate emulation is now supported in the eight-dimensional parameter space of w0waCDM+ ∑ mv models between redshift z = 0 and z = 3 for spatial scales within the range 0.01 ℎ Mpc−1 ≤ k ≤ 10 ℎ Mpc−1. In order to achieve this level of accuracy, we have had to improve the quality of the underlying N-body simulations used as training data: (i) we use self-consistent linear evolution of non-dark matter species such as massive neutrinos, photons, dark energy and the metric field, (ii) we perform the simulations in the so-called N-body gauge, which allows one to interpret the results in the framework of general relativity, (iii) we run over 250 high-resolution simulations with 30003 particles in boxes of 1(ℎ−1 Gpc)3 volumes based on paired-and-fixed initial conditions and (iv) we provide a resolution correction that can be applied to emulated results as a post-processing step in order to drastically reduce systematic biases on small scales due to residual resolution effects in the simulations. We find that the inclusion of the dynamical dark energy parameter wa significantly increases the complexity and expense of creating the emulator. The high fidelity of EuclidEmulator2 is tested in various comparisons against N-body simulations as well as alternative fast predictors like HALOFIT, HMCode and CosmicEmu. A blind test is successfully performed against the Euclid Flagship v2.0 simulation. Nonlinear correction factors emulated with EuclidEmulator2 are accurate at the level of 1% or better for 0.01 ℎ Mpc−1 ≤ k ≤ 10 ℎ Mpc−1 and z ≤ 3 compared to high-resolution dark matter only simulations. EuclidEmulator2 is publicly available at https://***/miknab/EuclidEmulator2. © 2020, CC-BY-NC-SA.

关键词： Power spectrum

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Fast Distributed Strategic Learning for Global Optima in Queueing Access Games

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IFAC Proceedings Volumes 2014年第3期47卷 7055-7060页

作者： Hamidou Tembine KAUST Strategic Research Initiative Center for Uncertainty Quantification in Computational Science and Engineering CEMSE KAUST

关键词： Coalitional learning queue access control

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Nonasymptotic Mean-Field Games

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IFAC Proceedings Volumes 2014年第3期47卷 8989-8994页

作者： Hamidou Tembine KAUST Strategic Research Initiative Center for Uncertainty Quantification in Computational Science and Engineering CEMSE KAUST

关键词： non-asymptotic mean-field game theory

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