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Efficient numerical methods for gas network modeling and simulation Netw. Heterog. Media (IF 1.053) Pub Date : 2020-08-26 Yue Qiu; Sara Grundel; Martin Stoll; Peter Benner
We study the modeling and simulation of gas pipeline networks, with a focus on fast numerical methods for the simulation of transient dynamics. The obtained mathematical model of the underlying network is represented by a system of nonlinear differential algebraic equations (DAEs). With our modeling approach, we reduce the number of algebraic constraints, which correspond to the $ (2,2) $ block in
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The selection problem for some first-order stationary Mean-field games Netw. Heterog. Media (IF 1.053) Pub Date : 2020-08-26 Diogo A. Gomes; Hiroyoshi Mitake; Kengo Terai
Here, we study the existence and the convergence of solutions for the vanishing discount MFG problem with a quadratic Hamiltonian. We give conditions under which the discounted problem has a unique classical solution and prove convergence of the vanishing-discount limit to a unique solution up to constants. Then, we establish refined asymptotics for the limit. When those conditions do not hold, the
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Modelling pattern formation through differential repulsion Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Julien Barré; Pierre Degond; Diane Peurichard; Ewelina Zatorska
Motivated by experiments on cell segregation, we present a two-species model of interacting particles, aiming at a quantitative description of this phenomenon. Under precise scaling hypothesis, we derive from the microscopic model a macroscopic one and we analyze it. In particular, we determine the range of parameters for which segregation is expected. We compare our analytical results and numerical
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Swarms dynamics approach to behavioral economy: Theoretical tools and price sequences Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Nicola Bellomo; Sarah De Nigris; Damián Knopoff; Matteo Morini; Pietro Terna
This paper presents a development of the mathematical theory of swarms towards a systems approach to behavioral dynamics of social and economical systems. The modeling approach accounts for the ability of social entities are to develop a specific strategy which is heterogeneously distributed by interactions which are nonlinearly additive. A detailed application to the modeling of the dynamics of prices
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Relative entropy method for the relaxation limit of hydrodynamic models Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 José Antonio Carrillo; Yingping Peng; Aneta Wróblewska-Kamińska
We show how to obtain general nonlinear aggregation-diffusion models, including Keller-Segel type models with nonlinear diffusions, as relaxations from nonlocal compressible Euler-type hydrodynamic systems via the relative entropy method. We discuss the assumptions on the confinement and interaction potentials depending on the relative energy of the free energy functional allowing for this relaxation
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A BGK kinetic model with local velocity alignment forces Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Young-Pil Choi; Seok-Bae Yun
The global Cauchy problem for a local alignment model with a relaxational inter-particle interaction operator is considered. More precisely, we consider the global-in-time existence of weak solutions of BGK model with local velocity-alignment term when the initial data have finite mass, momentum, energy, and entropy. The analysis involves weak/strong compactness based on the velocity moments estimates
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Micro- and macroscopic modeling of crowding and pushing in corridors Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Michael Fischer; Gaspard Jankowiak; Marie-Therese Wolfram
Experiments with pedestrians revealed that the geometry of the domain, as well as the incentive of pedestrians to reach a target as fast as possible have a strong influence on the overall dynamics. In this paper, we propose and validate different mathematical models at the micro- and macroscopic levels to study the influence of both effects. We calibrate the models with experimental data and compare
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Nonlinear stability of stationary solutions to the Kuramoto-Sakaguchi equation with frustration Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Seung-Yeal Ha; Hansol Park; Yinglong Zhang
We study measurable stationary solutions for the kinetic Kuramoto-Sakaguchi (in short K-S) equation with frustration and their stability analysis. In the presence of frustration, the total phase is not a conserved quantity anymore, but it is time-varying. Thus, we can not expect the genuinely stationary solutions for the K-S equation. To overcome this lack of conserved quantity, we introduce new variables
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Mean field models for large data–clustering problems Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Michael Herty; Lorenzo Pareschi; Giuseppe Visconti
We consider mean-field models for data–clustering problems starting from a generalization of the bounded confidence model for opinion dynamics. The microscopic model includes information on the position as well as on additional features of the particles in order to develop specific clustering effects. The corresponding mean–field limit is derived and properties of the model are investigated analytically
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Bounded confidence dynamics and graph control: Enforcing consensus Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 GuanLin Li; Sebastien Motsch; Dylan Weber
A generic feature of bounded confidence type models is the formation of clusters of agents. We propose and study a variant of bounded confidence dynamics with the goal of inducing unconditional convergence to a consensus. The defining feature of these dynamics which we name the No one left behind dynamics is the introduction of a local control on the agents which preserves the connectivity of the interaction
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Kinetic modelling of multiple interactions in socio-economic systems Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Giuseppe Toscani; Andrea Tosin; Mattia Zanella
Unlike the classical kinetic theory of rarefied gases, where microscopic interactions among gas molecules are described as binary collisions, the modelling of socio-economic phenomena in a multi-agent system naturally requires to consider, in various situations, multiple interactions among the individuals. In this paper, we collect and discuss some examples related to economic and gambling activities
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Synchronization of a Kuramoto-like model for power grids with frustration Netw. Heterog. Media (IF 1.053) Pub Date : 2020-09-09 Xiaoxue Zhao; Zhuchun Li
We discuss the complete synchronization for a Kuramoto-like model for power grids with frustration. For identical oscillators without frustration, it will converge to complete phase and frequency synchronization exponentially fast if the initial phases are distributed in a half circle. For nonidentical oscillators with frustration, we present a framework leading to complete frequency synchronization
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Simultaneous observability of infinitely many strings and beams Netw. Heterog. Media (IF 1.053) Pub Date : 2020-08-13 Vilmos Komornik; Anna Chiara Lai; Paola Loreti
We investigate the simultaneous observability of infinite systems of vibrating strings or beams having a common endpoint where the observation is taking place. Our results are new even for finite systems because we allow the vibrations to take place in independent directions. Our main tool is a vectorial generalization of some classical theorems of Ingham, Beurling and Kahane in nonharmonic analysis
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Homogenization of multivalued monotone operators with variable growth exponent Netw. Heterog. Media (IF 1.053) Pub Date : 2020-05-19 Svetlana Pastukhova; Valeria Chiadò Piat
We consider the Dirichlet problem for an elliptic multivalued maximal monotone operator $ {\mathcal A}_\varepsilon $ satisfying growth estimates of power type with a variable exponent. This exponent $ p_\varepsilon(x) $ and also the symbol of the operator $ {\mathcal A}_\varepsilon $ oscillate with a small period $ \varepsilon $ with respect to the space variable $ x $. We prove a homogenization result
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The band-gap structure of the spectrum in a periodic medium of masonry type Netw. Heterog. Media (IF 1.053) Pub Date : 2020-07-12 Günter Leugering; Sergei A. Nazarov; Jari Taskinen
We consider the spectrum of a class of positive, second-order elliptic systems of partial differential equations defined in the plane $ \mathbb{R}^2 $. The coefficients of the equation are assumed to have a special form, namely, they are doubly periodic and of high contrast. More precisely, the plane $ \mathbb{R}^2 $ is decomposed into an infinite union of the translates of the rectangular periodicity
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Perturbation analysis of the effective conductivity of a periodic composite Netw. Heterog. Media (IF 1.053) Pub Date : 2020-07-12 Paolo Luzzini; Paolo Musolino
We consider the effective conductivity $ \lambda^{\mathrm{eff}} $ of a periodic two-phase composite obtained by introducing into an infinite homogeneous matrix a periodic set of inclusions of a different material. Then we study the behavior of $ \lambda^{\mathrm{eff}} $ upon perturbation of the shape of the inclusions, of the periodicity structure, and of the conductivity of each material.
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New coupling conditions for isentropic flow on networks Netw. Heterog. Media (IF 1.053) Pub Date : 2020-07-12 Yannick Holle; Michael Herty; Michael Westdickenberg
We introduce new coupling conditions for isentropic flow on networks based on an artificial density at the junction. The new coupling conditions can be derived from a kinetic model by imposing a condition on energy dissipation. Existence and uniqueness of solutions to the generalized Riemann and Cauchy problem are proven. The result for the generalized Riemann problem is globally in state space. Furthermore
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Deep neural network approach to forward-inverse problems Netw. Heterog. Media (IF 1.053) Pub Date : 2020-04-30 Hyeontae Jo; Hwijae Son; Hyung Ju Hwang; Eun Heui Kim
In this paper, we construct approximated solutions of Differential Equations (DEs) using the Deep Neural Network (DNN). Furthermore, we present an architecture that includes the process of finding model parameters through experimental data, the inverse problem. That is, we provide a unified framework of DNN architecture that approximates an analytic solution and its model parameters simultaneously
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Comparative study of macroscopic traffic flow models at road junctions Netw. Heterog. Media (IF 1.053) Pub Date : 2020-04-30 Paola Goatin; Elena Rossi
We qualitatively compare the solutions of a multilane model with those produced by the classical Lighthill-Whitham-Richards equation with suitable coupling conditions at simple road junctions. The numerical simulations are based on the Godunov and upwind schemes. Several tests illustrate the models' behaviour in different realistic situations.
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A new mixed finite element method for the n-dimensional Boussinesq problem with temperature-dependent viscosity Netw. Heterog. Media (IF 1.053) Pub Date : 2020-04-10 Javier A. Almonacid; Gabriel N. Gatica; Ricardo Oyarzúa; Ricardo Ruiz-Baier
In this paper we propose a new mixed-primal formulation for heat-driven flows with temperature-dependent viscosity modeled by the stationary Boussinesq equations. We analyze the well-posedness of the governing equations in this mathematical structure, for which we employ the Banach fixed-point theorem and the generalized theory of saddle-point problems. The motivation is to overcome a drawback in a
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