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arXiv 2022年

作者： Steinhausen, Matthias Zirwes, Thorsten Ferraro, Federica Scholtissek, Arne Bockhorn, Henning Hasse, Christian Technical University of Darmstadt Department of Mechanical Engineering Simulation of reactive Thermo-Fluid Systems Otto-Berndt-Straße 2 Darmstadt64287 Germany Engler-Bunte-Institute Karlsruhe Institute of Technology Engler-Bunte-Ring 7 Karlsruhe76131 Germany Steinbuch Centre for Computing Karlsruhe Institute of Technology Hermann-von-Helmholtz-Platz 1 Eggenstein-Leopoldshafen76344 Germany

In this study, the thermochemical state during turbulent flame-wall interaction of a stoichiometric methane-air flame is investigated using a fully resolved simulation with detailed chemistry. The turbulent side-wall quenching flame shows both head-on quenching and side-wall quenching-like behavior that significantly affects the CO formation in the near-wall region. The detailed insights from the simulation are used to evaluate a recently proposed flame (tip) vortex interaction mechanism identified from experiments on turbulent side-wall quenching. It describes the entrainment of burnt gases into the fresh gas mixture near the flame’s quenching point. The flame behavior and thermochemical states observed in the simulation are similar to the phenomena observed in the experiments. A novel chemistry manifold is presented that accounts for both the effects of flame dilution due to exhaust gas recirculation in the flame vortex interaction area and enthalpy losses to the wall. The manifold is validated in an a-priori analysis using the simulation results as a reference. The incorporation of exhaust gas recirculation effects in the manifold leads to a significantly increased prediction accuracy in the near-wall regions of flame-vortex interactions. © 2022, CC BY-NC-ND.

关键词： Quenching

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TURBULENT FLAME-WALL INTERACTION OF PREMIXED FLAMES USING QUADRATURE-BASED MOMENT METHODS (QBMM) AND TABULATED CHEMISTRY: AN A PRIORI ANALYSIS

arXiv

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arXiv 2022年

作者： Steinhausen, Matthias Zirwes, Thorsten Ferraro, Federica Popp, Sebastian Zhang, Feichi Bockhorn, Henning Hasse, Christian Technical University of Darmstadt Department of Mechanical Engineering Simulation of reactive Thermo-Fluid Systems Otto-Berndt-Straße 2 Darmstadt64287 Germany Engler-Bunte-Institute Karlsruhe Institute of Technology Engler-Bunte-Ring 7 Karlsruhe76131 Germany Steinbuch Centre for Computing Karlsruhe Institute of Technology Hermann-von-Helmholtz-Platz 1 Eggenstein-Leopoldshafen76344 Germany

Presumed probability density function and transported PDF methods are commonly applied to model the turbulence chemistry interaction in turbulent reacting flows. However, little focus has been given to the turbulence chemistry interaction PDF closure for flame-wall interaction. In this study, a quasi-DNS of a turbulent premixed, stoichiometric methane-air flame ignited in a fully developed turbulent channel flow undergoing side-wall quenching is investigated. The objective of this study is twofold. First, the joint PDF of the progress variable and enthalpy, that needs to be accounted for in turbulence chemistry interaction closure models, is analyzed in the quasi-DNS configuration, both in the core flow and the near-wall region. Secondly, a transported PDF closure model, based on a Conditional Quadrature Method of Moments approach, and a presumed PDF approach are examined in an a priori analysis using the quasi-DNS as a reference both in the context of Reynolds-Averaged Navier Stokes (RANS) and Large-Eddy simulations (LESs). The analysis of the joint PDF demonstrates the high complexity of the reactive scalar distribution in the near-wall region. Here, a high correlation between the progress variable and enthalpy is found, where the flame propagation and quenching are present simultaneously. The transported PDF approach presented in this work, based on the Conditional Quadrature Method of Moments, accounts for the moments of the joint PDF of progress variable and enthalpy coupled to a Quenching-Flamelet Generated Manifold. In the a priori analysis both turbulence chemistry interaction PDF closure models show a high accuracy in the core flow. In the near-wall region, however, only the Conditional Quadrature Method of Moments approach is suitable to predict the flame structures. © 2022, CC BY-NC-ND.

关键词： Quenching

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UML-based combat effectiveness simulation system modeling within MDE

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Journal of systems Engineering and Electronics 2018年第6期29卷 1180-1196页

作者： ZHU Zhi LEI Yonglin SARJOUGHIAN Hessam LI Xiaobo ZHU Yifan Department of Military Modeling and Simulation School of Systems Engineering National University of Defense Technology Arizona Center for Integrated Modeling and Simulation School of Computing Informatics and Decision Systems EngineeringArizona State University

To reduce complexity, the combat effectiveness simulation system(CESS) is often decomposed into static structure,physical behavior, and cognitive behavior, and model abstraction is layered onto domain invariant knowledge(DIK) and application variant knowledge(AVK) levels. This study concentrates on the specification of CESS’s physical behaviors at the DIK level of abstraction, and proposes a model driven framework for efficiently developing simulation models within model-driven engineering(MDE). Technically, this framework integrates the four-layer metamodeling architecture and a set of model transformation techniques with the objective of reducing model heterogeneity and enhancing model continuity. As a proof of concept, a torpedo example is illustrated to explain how physical models are developed following the proposed framework. Finally, a combat scenario is constructed to demonstrate the availability, and a further verification is shown by a reasonable agreement between simulation results and field observations.

关键词： domain specific modeling model-driven development system engineering effectiveness simulation

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The optimality principle "mathematical expectation-var" and its application in the Russian stock market 12

The optimality principle "mathematical expectation-var" and ...

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12th International Conference "Management of Large-Scale System Development", MLSD 2019

作者： Gorelik, Victor Zolotova, Tatiana Dorodnicyn Computing Centre FRC CSC RAS Department of Simulation Systems and Operations Research Moscow Russia Financial University Government of the Russian Federation Department of Data Analysis Moscow Russia

ISBN: (纸本)9781728117300

An approach to the selection of optimality criteria in stochastic investment problems modeled as games with nature with known probabilities of states is proposed. This approach is based on the combination of efficiency criteria (expected payoff) and risk criteria (such as VAR). For the emerging two-criterion problem, the method of a transfer of one criterion into a constraint is used as a method of formalization. The case of pure strategies (the choice of one investment option) and the case of mixed strategies (diversification of investments) are considered. © 2019 IEEE.

关键词： Efficiency

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Asymptotic Bayesian Generalization Error in Latent Dirichlet Allocation and Stochastic Matrix Factorization

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SN Computer Science 2020年第2期1卷 1-22页

作者： Hayashi, Naoki Watanabe, Sumio Simulation & Mining Division NTT DATA Mathematical Systems Inc. 1F Shinano-machi-Renga-kan Shinano-machi 35 Tokyo Shinjuku-Ku 160-0016 Japan Department of Mathematical and Computing Science Tokyo Institute of Technology W8-42 Tokyo 2-12-1 Oookayama Meguro-ku 152-8552 Japan

Latent Dirichlet allocation (LDA) is useful in document analysis, image processing, and many information systems;however, its generalization performance has been left unknown because it is a singular learning machine to which regular statistical theory can not be applied. Stochastic matrix factorization (SMF) is a restricted matrix factorization in which matrix factors are stochastic;the column of the matrix is in a simplex. SMF is being applied to image recognition and text mining. We can understand SMF as a statistical model by which a stochastic matrix of given data is represented by a product of two stochastic matrices, whose generalization performance has also been left unknown because of non-regularity. In this paper, using an algebraic and geometric method, we show the analytic equivalence of LDA and SMF, both of which have the same real log canonical threshold (RLCT), resulting in that they asymptotically have the same Bayesian generalization error and the same log marginal likelihood. Moreover, we derive the upper bound of the RLCT and prove that it is smaller than the dimension of the parameter divided by two, hence the Bayesian generalization errors of them are smaller than those of regular statistical models. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Algebraic geometry Bayesian learning Latent Dirichlet allocation Matrix factorization Singular model Topic model

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Assembly Theory Reduced to Shannon entropy and Rendered Redundant by Naive Statistical Algorithms

arXiv

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arXiv 2024年

作者： Ozelim, Luan Uthamacumaran, Abicumaran Abrahão, Felipe S. Hernández-Orozco, Santiago Kiani, Narsis A. Tegnér, Jesper Zenil, Hector Oxford Immune Algorithmics Oxford University Innovation United Kingdom Center for Logic Epistemology and The History of Science University of Campinas Brazil DEXL National Laboratory for Scientific Computing Brazil Department of Oncology-Pathology Center for Molecular Medicine Karolinska Institutet Sweden Algorithmic Dynamics Lab Karolinska Institutet Sweden King’s College London United Kingdom Dept. Physics and Psychology Concordia University Canada McGill University Neurosurgical Simulation and Artificial Intelligence Learning Centre Canada Living Systems Lab KAUST Saudi Arabia School of Biomedical Engineering and Imaging Sciences King’s Institute for Artificial Intelligence King’s College London United Kingdom

We respond to arguments against our critique of Assembly Theory that claim to show its divergence from popular compression. We have proven that any implementation of the concept of ‘copy number’ underlying Assembly Theory (AT) and its assembly index (Ai) is equivalent to Shannon entropy, and not fundamentally or methodologically different from algorithms like ZIP compression. Here we show that the weak empirical correlation between Ai and LZW, which the authors have offered as a defence is based on an incomplete and misleading experiment. When the experiment is completed, the fast asymptotic convergence to LZ compression and Shannon entropy is undeniable, just as their mathematical proof of equivalence remains undisputed. This contribution completes the theoretical and empirical demonstration that any variation of the copy-number concept underlying AT, which entails counting the number of object repetitions ‘to arrive at a measure for life,’ is equivalent to statistical compression and Shannon entropy. We demonstrate that the authors’ ‘we-are-better-because-we-are-worse’ argument against compression does not withstand basic scrutiny, and that their empirical results separating organic from inorganic compounds have not only been previously reported, sans claims to unify physics and biology, but are driven solely by molecular length– which they did not control for– rather than by any particular feature of life captured by Assembly Theory or their index. Finally, we show that Ai is a particular case of our Block Decomposition Method, introduced almost a decade earlier, and that arguments attributing special stochastic properties to Ai are misleading, since the properties of Ai are not unique, but rather exactly the same as those that Shannon entropy possesses and for which it was designed in the first place–for the quantification of uncertainty–and which we have proven to be equivalent to Ai. Shannon entropy is already not only equipped with stochasticity but was desig

关键词： Stochastic systems

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Nonequilibrium cavity QED model accounting for dipole-dipole interaction in strong-, ultrastrong-, and deep-strong-coupling regimes

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Physical Review A 2020年第1期102卷 013701-013701页

作者： Asha Devi Sarath D. Gunapala Mark I. Stockman Malin Premaratne Advanced Computing and Simulation Laboratory Department of Electrical and Computer Systems Engineering Monash University Clayton Victoria 3800 Australia Jet Propulsion Laboratory California Institute of Technology Pasadena California 91109 USA Department of Physics and Astronomy Georgia State University Atlanta Georgia 30303 USA

We propose a generalized system of nonequilibrium cavity QED with interacting dipoles coupled to a single-mode of an electromagnetic field in strong-, ultrastrong-, and deep-strong-coupling regimes. To illustrate the applicability of the system, an extended Dicke model is developed for atoms undergoing Raman transitions between the ground states in the presence of laser fields and considering dipole-dipole interactions; the latter has been neglected in many previous works. We have studied the effect of a ferroelectric and an antiferroelectric arrangement on the phase transition for both a finite and an infinite number of dipoles. An additional superradiant phase is observed in the deep-strong-coupling regime due to influence of the dipole-dipole interaction term. A high degree of dipole-dipole entanglement occurs for the antiferroelectric arrangement in the deep-strong regime, whereas it gets disentangled quite rapidly for the ferroelectric arrangement. A sharp transition of system parameters is observed in the ultrastrong-coupling regime and beyond. The dipole-dipole interaction also influences the spectra of the system, inducing a significant shift in the peaks, and modifies the average number of photons emitted.

关键词： Atoms, ions, & molecules in cavities Cavity quantum electrodynamics Nanophotonics

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Optically controlled quantum thermal gate

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Physical Review B 2020年第24期101卷 245402-245402页

作者： Ravi T. Wijesekara Sarath D. Gunapala Mark I. Stockman Malin Premaratne Advanced Computing and Simulation Laboratory(AχL) Department of Electrical and Computer Systems Engineering Monash University Clayton Victoria 3800 Australia Jet Propulsion Laboratory California Institute of Technology Pasadena California 91109 USA Department of Physics and Astronomy Georgia State University Atlanta Georgia 30303 USA

The ability to actively control heat flows in the nanoscale can open up a plethora of opportunities for applications that require thermal management and regulation. We show that it is possible to build a three-terminal quantum thermal gating device which regulates the thermal conductivity between two of its terminals in response to light incident upon the remaining terminal. We model our device as three mutually coupled two-level systems which interact thermally and optically with their environment. To incorporate the thermal interactions of our device, we adopt an open quantum systems framework under the Born-Markov approximation. We subsequently use detailed quantum mechanical state analysis to illustrate its operating principle. Through numerical simulations, we further explore the nonlinear relationship between the optical field amplitude and the thermal conductivity of the device in the steady-state regime. Based on our investigations, we find that the energy-gating behavior of our device is highly efficient in that it can control a significantly larger thermal energy flow compared to the amount of energy it absorbs from the optical field in the process. The approach we have taken to analyze the system, in particular the graphical representations we developed to intuitively and concisely represent the quantum states, energy flows, and the relationships between them, could be of value in analyzing other similar thermo-optical systems. Thus, we envision that both the device concept and its analysis technique would be useful to researchers working in this area.

关键词： Electronic transitions Open quantum systems Thermal properties Transistors

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Broken poloidal symmetry and plasmonic eigenmodes on a torus

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Physical Review B 2020年第11期101卷 115426-115426页

作者： Tharindu Warnakula Sarath D. Gunapala Mark I. Stockman Malin Premaratne Advanced Computing and Simulation Laboratory (AχL) Department of Electrical and Computer Systems Engineering Monash University Clayton Vic 3800 Australia Jet Propulsion Laboratory California Institute of Technology Pasadena California 91109 USA Department of Physics and Astronomy Georgia State University Atlanta Georgia 30303 USA

We study the poloidal modes (modes whose variations are strictly along the direction of the torus axis) of toroidal nanoparticles. We show that the modes may be understood in terms of the symmetry breaking that occurs when an infinite cylinder is folded to form a torus. This symmetry breaking results in the splitting of the transverse cylinder modes into two distinct sets of modes on a torus. One set of these modes was known to exist already. We show the existence of the second set and also analytically derive the surface charge structure for that set of modes. We also consolidate recent advances made in studying the modal structure on torus particles and complete our understanding of the plasmonic modes of a torus.

关键词： Electromagnetic field calculations Plasmonics Surface plasmons Nanoparticles

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Augmenting photoluminescence of monolayer MoS_(2) using high order modes in a metal dimer-on-film nanocavity

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Photonics Research 2021年第4期9卷 501-506页

作者： Shiyin Cao Liping Hou Qifa Wang Chenyang Li Weixing Yu Xuetao Gan Kaihui Liu Malin Premaratne Fajun Xiao Jianlin Zhao MOE Key Laboratory of Material Physics and Chemistry under Extraordinary Conditions and Shaanxi Key Laboratory of Optical Information TechnologySchool of Physical Science and TechnologyNorthwestern Polytechnical UniversityXi’an 710129China Key Laboratory of Spectral Imaging Technology of Chinese Academy of Sciences Xi’an 710119China State Key Laboratory for Mesoscopic Physics Collaborative Innovation Centre of Quantum MatterSchool of PhysicsPeking UniversityBeijing 100871China Advanced Computing and Simulation Laboratory(AχL) Department of Electrical and Computer Systems EngineeringMonash UniversityClaytonVIC 3800Australia

Plasmonic particle-on-film nanocavities,supporting gap modes with ultra-small volume,provide a great solution to boost light–matter interactions at the *** this work,we report on the photoluminescence(PL)enhancement of monolayer MoS_(2) using high order modes of an Au nanosphere dimer-on-film nanocavity(DoFN).The high order plasmon modes,consisting of two bonding quadrupoles in the dimer and their images in the Au film,are revealed by combining the polarization-resolved scattering spectra with the numerical *** integrating the monolayer MoS_(2) into the DoFN,these high order modes are used to enhance PL intensity through simultaneously boosting the absorption and emission processes,producing a 1350-fold enhancement *** opens an avenue to enhance the light–matter interaction with high order plasmon modes and may find applications in future optoelectronics and nanophotonics devices.

关键词： cavity high integrating

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