Editorial

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74 KiB

Open AccessEditorial

Editor-in-Chief's Report

by Michel Petitjean

Entropy 2006, 8(2), 110-112; https://doi.org/10.3390/e8020110 - 14 Jun 2006

Cited by 1 | Viewed by 3709

Abstract

Entropy has been launched in 1999 by Dr. Shu-Kun Lin, and it is now in its eight year.[...] Full article

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192 KiB

Open AccessArticle

Entropy Generation in Pressure Gradient Assisted Couette Flow with Different Thermal Boundary Conditions

by Abdul Aziz

Entropy 2006, 8(2), 50-62; https://doi.org/10.3390/e8020050 - 04 May 2006

Cited by 29 | Viewed by 9843

Abstract

The present paper is concerned with an analytical study of entropy generation in viscous, incompressible Couette flow between a stationary plate and a moving plate. The flow induced by the moving plate is assisted by a constant pressure gradient along the flow direction. [...] Read more.

The present paper is concerned with an analytical study of entropy generation in viscous, incompressible Couette flow between a stationary plate and a moving plate. The flow induced by the moving plate is assisted by a constant pressure gradient along the flow direction. Four different combinations of thermal boundary conditions are investigated: (a) plates at different temperatures, (b) stationary plate at a fixed temperature and moving plate subjected to a constant heat flux, (c) stationary plate at a fixed temperature and convection at the moving plate, and (d) convection at both plates. Besides the velocity and temperature profiles, dimensionless results are presented for the entropy generated due to heat transfer, the entropy generated due to viscous dissipation, and the total entropy generation. These results illustrate the effect of pressure gradient, temperature asymmetry, heat flux, convection Biot numbers, and ambient temperatures. For certain combinations of thermal variables, the total entropy generated is minimized. Full article

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109 KiB

Open AccessArticle

Entropy and Energy in Quantum Measurement

by Andreas E. Schlatter

Entropy 2006, 8(2), 63-66; https://doi.org/10.3390/e8020063 - 12 May 2006

Cited by 3 | Viewed by 4305

Abstract

On the basis of the classical axioms of non relativistic quantum mechanics, we develop a model for the interplay between energy and entropy in the process of quantum measurement and shed light on the scope of some of the axioms with regard to [...] Read more.

On the basis of the classical axioms of non relativistic quantum mechanics, we develop a model for the interplay between energy and entropy in the process of quantum measurement and shed light on the scope of some of the axioms with regard to the measurement problem. Full article

215 KiB

Open AccessArticle

Inference with the Median of a Prior

by Adel Mohammadpour and Ali Mohammad-Djafari

Entropy 2006, 8(2), 67-87; https://doi.org/10.3390/e8020067 - 13 Jun 2006

Cited by 1 | Viewed by 6047

Abstract

We consider the problem of inference on one of the two parameters of a probability distribution when we have some prior information on a nuisance parameter. When a prior probability distribution on this nuisance parameter is given, the marginal distribution is the classical [...] Read more.

We consider the problem of inference on one of the two parameters of a probability distribution when we have some prior information on a nuisance parameter. When a prior probability distribution on this nuisance parameter is given, the marginal distribution is the classical tool to account for it. If the prior distribution is not given, but we have partial knowledge such as a fixed number of moments, we can use the maximum entropy principle to assign a prior law and thus go back to the previous case. In this work, we consider the case where we only know the median of the prior and propose a new tool for this case. This new inference tool looks like a marginal distribution. It is obtained by first remarking that the marginal distribution can be considered as the mean value of the original distribution with respect to the prior probability law of the nuisance parameter, and then, by using the median in place of the mean. Full article

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373 KiB

Open AccessArticle

Symmetry Studies and Decompositions of Entropy

by Marlos Viana

Entropy 2006, 8(2), 88-109; https://doi.org/10.3390/e8020088 - 14 Jun 2006

Cited by 8 | Viewed by 5342

Abstract

This paper describes a group-theoretic method for decomposing the entropy of a finite ensemble when symmetry considerations are of interest. The cases in which the elements in the ensemble are indexed by {1,2,...,n} and by the permutations of a finite set are considered [...] Read more.

This paper describes a group-theoretic method for decomposing the entropy of a finite ensemble when symmetry considerations are of interest. The cases in which the elements in the ensemble are indexed by {1,2,...,n} and by the permutations of a finite set are considered in detail and interpreted as particular cases of ensembles with elements indexed by a set subject to the actions of a finite group. Decompositions for the entropy in binary ensembles and in ensembles indexed by short DNA words are discussed. Graphical descriptions of the decompositions of the entropy in geological samples are illustrated. The decompositions derived in the present cases follow from a systematic data analytic tool to study entropy data in the presence of symmetry considerations. Full article

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100 KiB

Open AccessLetter

Remarks on the Compatibility of Opposite Arrows of Time II

by H. D. Zeh

Entropy 2006, 8(2), 44-49; https://doi.org/10.3390/e8010044 - 05 Apr 2006

Cited by 7 | Viewed by 5973

Abstract

In a series of papers [1,2,3], Lawrence Schulman presented examples which demonstrate the compatibility of opposite arrows of time in various situations. In a previous letter to this journal [4] I questioned some of them for not being realistic in spite of being [...] Read more.

In a series of papers [1,2,3], Lawrence Schulman presented examples which demonstrate the compatibility of opposite arrows of time in various situations. In a previous letter to this journal [4] I questioned some of them for not being realistic in spite of being logically correct. Schulman replied [5] to these objections in a letter directly succeeding my one. I am here trying to clarify some aspects of the dispute, thereby further explaining and supporting my previous conclusions. Full article

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Entropy, Volume 8, Issue 2 (June 2006) – 6 articles , Pages 44-112

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