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Publications (10 of 78) Show all publications
Lind, M. & Muntean, A. (2018). A Priori Feedback Estimates for Multiscale Reaction-Diffusion Systems. Numerical Functional Analysis and Optimization, 39(4), 413-437
Open this publication in new window or tab >>A Priori Feedback Estimates for Multiscale Reaction-Diffusion Systems
2018 (English)In: Numerical Functional Analysis and Optimization, ISSN 0163-0563, E-ISSN 1532-2467, Vol. 39, no 4, p. 413-437Article in journal (Refereed) Published
Abstract [en]

We study the approximation of a multiscale reaction–diusion system posed on both macroscopic and microscopic space scales. The coupling between the scales is done through micro– macro ux conditions. Our target system has a typical structure for reaction–diusion ow problems in media with distributed microstructures (also called, double porosity materials). Besides ensuring basic estimates for the convergence of two-scale semidiscrete Galerkin approximations, we provide a set of a priori feedback estimates and a local feedback error estimator that help in designing a distributed-high-errors strategy to allow for a computationally ecient zooming in and out from microscopic structures. The error control on the feedback estimates relies on two-scale-energy, regularity, and interpolation estimates as well as on a ne bookeeping of the sources responsible with the propagation of the (multiscale) approximation errors. The working technique based on a priori feedback estimates is in principle applicable to a large class of systems of PDEs with dual structure admitting strong solutions. A

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
Feedback nite element method, Galerkin approximation, micro–macro coupling, multiscale reaction–diusion systems
National Category
Mathematics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-62808 (URN)10.1080/01630563.2017.1369996 (DOI)
Available from: 2017-08-25 Created: 2017-08-25 Last updated: 2018-05-22Bibliographically approved
Muntean, A. & Seidman, T. I. (2018). Asymptotics of diffusion-limited fast reactions. Quarterly of Applied Mathematics, 76, 199-213
Open this publication in new window or tab >>Asymptotics of diffusion-limited fast reactions
2018 (English)In: Quarterly of Applied Mathematics, ISSN 0033-569X, E-ISSN 1552-4485, Vol. 76, p. 199-213Article in journal (Refereed) Published
Place, publisher, year, edition, pages
American Mathematical Society (AMS), 2018
Keywords
Fast reaction, diffusion, asymptotics
National Category
Mathematics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-47555 (URN)10.1090/qam/1496 (DOI)
Available from: 2016-12-25 Created: 2016-12-25 Last updated: 2018-05-23Bibliographically approved
Gruetzner, S. & Muntean, A. (2018). Brief Introduction to Damage Mechanics and its Relation to Deformations. In: van Meurs, Patrick, Kimura, Masato, Notsu, Hirofumi (Ed.), Mathematical Analysis of Continuum Mechanics and Industrial Applications II: Proceedings of the International Conference CoMFoS16 (pp. 115-124). Springer
Open this publication in new window or tab >>Brief Introduction to Damage Mechanics and its Relation to Deformations
2018 (English)In: Mathematical Analysis of Continuum Mechanics and Industrial Applications II: Proceedings of the International Conference CoMFoS16 / [ed] van Meurs, Patrick, Kimura, Masato, Notsu, Hirofumi, Springer, 2018, p. 115-124Chapter in book (Refereed)
Abstract [en]

We discuss some principle concepts of damage mechanics and outline a possibility to address the open question of the damage-to-deformation relation by suggesting a parameter identification setting. To this end, we introduce a variable motivated by the physical damage phenomenon and comment on its accessibility through measurements. We give an extensive survey on analytic results and present an isotropic irreversible partial damage model in a dynamic mechanical setting in form of a second order hyperbolic equation coupled with an ordinary differential equation for the damage evolution. We end with a note on a possible parameter identification setting.

Place, publisher, year, edition, pages
Springer, 2018
Series
Mathematics for Industry, ISSN 2198-350X ; 30
Keywords
damage, mechanics of solids, non-linear differential equations, parameter identification
National Category
Mathematics
Research subject
Materials Engineering; Mathematics
Identifiers
urn:nbn:se:kau:diva-63936 (URN)978-981-10-6283-4 (ISBN)
Available from: 2017-09-24 Created: 2017-09-24 Last updated: 2018-06-28Bibliographically approved
Muntean, A. & Reichelt, S. (2018). Corrector estimates for a thermo-diffusion model with weak thermal coupling. Multiscale Modeling & simulation, 16(2), 807-832
Open this publication in new window or tab >>Corrector estimates for a thermo-diffusion model with weak thermal coupling
2018 (English)In: Multiscale Modeling & simulation, ISSN 1540-3459, E-ISSN 1540-3467, Vol. 16, no 2, p. 807-832Article in journal (Refereed) Published
Abstract [en]

The present work deals with the derivation of corrector estimates for the two-scale homogenization of a thermodiffusion model with weak thermal coupling posed in a heterogeneous medium endowed with periodically arranged high-contrast microstructures. The term “weak thermal coupling” refers here to the variable scaling in terms of the small homogenization parameter $\varepsilon$ of the heat conduction-diffusion interaction terms, while the “high-contrast” is considered particularly in terms of the heat conduction properties of the composite material. As a main target, we justify the first-order terms of the multiscale asymptotic expansions in the presence of coupled fluxes, induced by the joint contribution of Sorret and Dufour-like effects. The contrasting heat conduction combined with cross coupling leads to the main mathematical difficulty in the system. Our approach relies on the method of periodic unfolding combined with $\varepsilon$-independent estimates for the thermal and concentration fields and for their coupled fluxes.

Place, publisher, year, edition, pages
Society for Industrial and Applied Mathematics, 2018
National Category
Mathematics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-65815 (URN)10.1137/16M109538X (DOI)000436998500009 ()
Available from: 2018-01-25 Created: 2018-01-25 Last updated: 2018-09-05Bibliographically approved
Richardson, O., Jalba, A. & Muntean, A. (2018). Effects of Environment Knowledge in Evacuation Scenarios Involving Fire and Smoke: A Multiscale Modelling and Simulation Approach. Fire technology, 1-22
Open this publication in new window or tab >>Effects of Environment Knowledge in Evacuation Scenarios Involving Fire and Smoke: A Multiscale Modelling and Simulation Approach
2018 (English)In: Fire technology, ISSN 0015-2684, E-ISSN 1572-8099, p. 1-22Article in journal (Refereed) Epub ahead of print
Abstract [en]

We study the evacuation dynamics of a crowd evacuating from a complex geometry in the presence of a fire as well as of a slowly spreading smoke curtain.The crowd is composed of two kinds of individuals: those who know the layout of the building, and those who do not and rely exclusively on potentially informed neighbors to identify a path towards the exit. We aim to capture the effect the knowledge of the environment has on the interaction between evacuees and their residence time in the presence of fire and evolving smoke. Our approach is genuinely multiscale—we employ a two-scale model that is able to distinguish between compressible and incompressible pedestrian flow regimes and allows for micro and macro pedestrian dynamics. Simulations illustrate the expected qualitative behavior of the model. We finish with observations on how mixing evacuees with different levels of knowledge impacts important evacuation aspects.

Place, publisher, year, edition, pages
Springer, 2018
Keywords
Crowd dynamics, Environment knowledge, Evacuation, Fire and smoke dynamics, Particle methods, Transport processes, Incompressible flow, Smoke, Transport process, Fires
National Category
Mathematics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-68390 (URN)10.1007/s10694-018-0743-x (DOI)2-s2.0-85048553425 (Scopus ID)
Available from: 2018-07-04 Created: 2018-07-04 Last updated: 2018-08-15Bibliographically approved
Muntean, A., Cirillo, E. & van Santen, R. (2018). Particle-based modeling of flow through obstacles. In: Procceedings of ICMS, Eindhoven, NL: . World Scientific
Open this publication in new window or tab >>Particle-based modeling of flow through obstacles
2018 (English)In: Procceedings of ICMS, Eindhoven, NL, World Scientific, 2018Chapter in book (Refereed)
Place, publisher, year, edition, pages
World Scientific, 2018
National Category
Robotics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-65989 (URN)
Available from: 2018-01-29 Created: 2018-01-29 Last updated: 2018-06-27
Muntean, A. (2018). Preface. Applicable Analysis, 97(1), 1-2
Open this publication in new window or tab >>Preface
2018 (English)In: Applicable Analysis, ISSN 0003-6811, E-ISSN 1563-504X, Vol. 97, no 1, p. 1-2Article in journal (Refereed) Published
Place, publisher, year, edition, pages
Taylor & Francis, 2018
National Category
Natural Sciences Mathematics
Research subject
Mathematics; Mathematics
Identifiers
urn:nbn:se:kau:diva-65303 (URN)10.1080/00036811.2017.1397317 (DOI)
Note

Preface for the Special Issue "Multiscale Inverse Problems"

Available from: 2017-12-01 Created: 2017-12-01 Last updated: 2017-12-04Bibliographically approved
Lind, M., Muntean, A. & Richardson, O. (2018). Well-posedness and inverse Robin estimate for a multiscale elliptic/parabolic system. Applicable Analysis, 97(1), 89-106
Open this publication in new window or tab >>Well-posedness and inverse Robin estimate for a multiscale elliptic/parabolic system
2018 (English)In: Applicable Analysis, ISSN 0003-6811, E-ISSN 1563-504X, Vol. 97, no 1, p. 89-106Article in journal (Refereed) Published
Abstract [en]

We establish the well-posedness of a coupled micro–macro parabolic– elliptic system modeling the interplay between two pressures in a gas–liquid mixture close to equilibrium that is filling a porous media with distributed microstructures. Additionally, we prove a local stability estimate for the inverse micro–macro Robin problem, potentially useful in identifying quantitatively a micro–macro interfacial Robin transfer coefficient given microscopic measurements on accessible fixed interfaces. To tackle the solvability issue we use two-scale energy estimates and twoscale regularity/compactness arguments cast in the Schauder’s fixed point theorem. A number of auxiliary problems, regularity, and scaling arguments are used in ensuring the suitable Fréchet differentiability of the solution and the structure of the inverse stability estimate.

Place, publisher, year, edition, pages
Taylor & Francis, 2018
Keywords
Upscaled porous media, two-scale PDE, inverse micro–macro Robin problem
National Category
Mathematics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-62809 (URN)10.1080/00036811.2017.1364366 (DOI)
Available from: 2017-08-25 Created: 2017-08-25 Last updated: 2018-06-12Bibliographically approved
Eden, M. & Muntean, A. (2017). Corrector estimates for the homogenization of a two-scale thermoelasticity problem with a priori known phase transformations. Electronic Journal of Differential Equations (57), 1-21
Open this publication in new window or tab >>Corrector estimates for the homogenization of a two-scale thermoelasticity problem with a priori known phase transformations
2017 (English)In: Electronic Journal of Differential Equations, ISSN 1550-6150, E-ISSN 1072-6691, no 57, p. 1-21Article in journal (Refereed) Published
Abstract [en]

We investigate corrector estimates for the solutions of a thermoelasticity problem posed in a highly heterogeneous two-phase medium and its corresponding two-scale thermoelasticity model which was derived in [11] by two-scale convergence arguments. The medium in question consists of a connected matrix with disconnected, initially periodically distributed inclusions separated by a sharp interface undergoing a priori known phase transformations. While such estimates seem not to be obtainable in the fully coupled setting, we show that for some simplified scenarios optimal convergence rates can be proven rigorously. The main technique for the proofs are energy estimates using special reconstructions of two-scale functions and particular operator estimates for periodic functions with zero average. Here, additional regularity results for the involved functions are necessary.

Keywords
Homogenization; two-phase thermoelasticity; corrector estimates; time-dependent domains; distributed microstructures
National Category
Mathematical Analysis
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-47970 (URN)000395716400001 ()
Available from: 2017-02-17 Created: 2017-02-17 Last updated: 2018-08-20
Cirillo, E., Colangeli, M. & Muntean, A. (2017). Trapping in bottlenecks: Interplay between microscopic dynamics and large scale effects. Physica A: Statistical Mechanics and its Applications, 488(11), 30-38
Open this publication in new window or tab >>Trapping in bottlenecks: Interplay between microscopic dynamics and large scale effects
2017 (English)In: Physica A: Statistical Mechanics and its Applications, ISSN 0378-4371, E-ISSN 1873-2119, Vol. 488, no 11, p. 30-38Article in journal (Refereed) Published
Abstract [en]

We investigate the appearance of trapping states in pedestrian flows through bottlenecks as a result of the interplay between the geometry of the system and the microscopic stochastic dynamics. We model the flow through a bottleneck via a Zero Range Process on a one-dimensional periodic lattice. Particle are removed from the lattice sites with rates proportional to the local occupation numbers. The bottleneck is modeled by a particular site of the lattice whose updating rate saturates to a constant value as soon as the local occupation number exceeds a fixed threshold. We show that for any finite value of the threshold the stationary particle current saturates to the limiting bottleneck rate when the total particle density in the system exceeds a critical value corresponding to the bottleneck rate itself.

Place, publisher, year, edition, pages
Elsevier, 2017
Keywords
Pedestrian flows through bottlenecks, Trapping, Condensation, Stochastic modeling, Interacting particle systems
National Category
Mathematics
Research subject
Mathematics
Identifiers
urn:nbn:se:kau:diva-56724 (URN)10.1016/j.physa.2017.07.001 (DOI)
Note

Fulltexten är den inskickade versionen och har inte genomgått peer-review.

Available from: 2017-07-03 Created: 2017-07-03 Last updated: 2017-12-07Bibliographically approved
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ORCID iD: ORCID iD iconorcid.org/0000-0002-1160-0007

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