In this paper a kind of partial subadditivity of the entropy is investigated in probability theory and in matrix theory. We show some new inequalities related to the subadditivity of the standard entropy and its one-parameter generalization in the discrete case. The matrix analogues of the inequalities are also studied. The standard entropy is related to the function −x log x, but here some oth...

A review of the maximum entropy spectral analysis (MESA) method for time series is presented. Then, empirical evidence based on maximum entropy spectra of real seismic data is shown to suggest that M = 2N/ ln 2N is a reasonable a priori choice of the operator length M for discrete time series of length N . Various data examples support this conclusion.

Discrete-time linear time-varying can be represented using infinite dimensional operators. Using this representation the well-known definition of the entropy for time-invariant systems can be extended to this class of systems. In this paper we characterize the controller which minimizes the entropy in the case that full information is available.

We present numerical discretizations which preserve the entropy structure of the analyzed nonlinear diffusive equations. More precisely, we develop numerical schemes for which the discrete entropy is stable or even dissipating. The key idea is to ”translate” entropydissipation methods to the discrete case. We consider two situations. First, an implicit Euler finite-volume approximation of porou...

For the high order numerical approximation of hyperbolic systems of conservation laws, we propose to use as a building principle an entropy diminishing criterion instead of the familiar total variation diminishing criterion introduced by Harten for scalar equations. Based on this new criterion, we derive entropy diminishing projections that ensure, both, the second order of accuracy and all of ...

We present new numerical models for computing transitional or rarefied gas flows as described by the Boltzmann-BGK and BGK-ES equations. We first propose a new discrete-velocity model, based on the entropy minimization principle. This model satisfies the conservation laws and the entropy dissipation. Moreover, the problem of conservation and entropy for axisymmetric flows is investigated. We fi...

The entropy solutions of the compressible Euler equations satisfy a minimum principle for the specific entropy [10]. First order schemes such as Godunov-type and Lax-Friedrichs schemes and the second order kinetic schemes [6] also satisfy a discrete minimum entropy principle. In this paper, we show an extension of the positivity-preserving high order schemes for the compressible Euler equations...

This paper presents a study to achieve discrete entropy consistency using artificial and physical diffusion mechanisms. The study begins with the one-dimensional viscous Burgers equation, specifically looking at the shock results of entropy-conserved fluxes combined with a few choices of artificial and physical viscous diffusions. The approach is then repeated for the Navier–Stokes equations. O...

In this paper we advance the entropy theory of discrete nonautonomous dynamical systems that was initiated by Kolyada and Snoha in 1996. The first part of the paper is devoted to the measure-theoretic entropy theory of general topological systems. We derive several conditions guaranteeing that an initial probability measure, when pushed forward by the system, produces an invariant measure seque...

The entropy solutions of the compressible Euler equations satisfy a minimum principle for the specific entropy [11]. First order schemes such as Godunov-type and Lax-Friedrichs schemes and the second order kinetic schemes [6] also satisfy a discrete minimum entropy principle. In this paper, we show an extension of the positivity-preserving high order schemes for the compressible Euler equations...