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Entropy, Volume 19, Issue 3 (March 2017) – 48 articles

Cover Story (view full-size image): Free energy transduction can be obtained when external oscillating fields couple to internal conformational fluctuations contributing to the maintenance of a non-equilibrium state. This would explain the high efficiencies observed in the mechanisms of electrochemical signaling in living cells. The use of structure-based theoretical approaches allows assessing how fluctuation-driven transport occurs in confined systems such as protein channels with unprecedented detail. View this paper
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1619 KiB  
Article
Structure and Dynamics of Water at Carbon-Based Interfaces
by Jordi Martí, Carles Calero and Giancarlo Franzese
Entropy 2017, 19(3), 135; https://doi.org/10.3390/e19030135 - 21 Mar 2017
Cited by 16 | Viewed by 6481
Abstract
Water structure and dynamics are affected by the presence of a nearby interface. Here, first we review recent results by molecular dynamics simulations about the effect of different carbon-based materials, including armchair carbon nanotubes and a variety of graphene sheets—flat and with corrugation—on [...] Read more.
Water structure and dynamics are affected by the presence of a nearby interface. Here, first we review recent results by molecular dynamics simulations about the effect of different carbon-based materials, including armchair carbon nanotubes and a variety of graphene sheets—flat and with corrugation—on water structure and dynamics. We discuss the calculations of binding energies, hydrogen bond distributions, water’s diffusion coefficients and their relation with surface’s geometries at different thermodynamical conditions. Next, we present new results of the crystallization and dynamics of water in a rigid graphene sieve. In particular, we show that the diffusion of water confined between parallel walls depends on the plate distance in a non-monotonic way and is related to the water structuring, crystallization, re-melting and evaporation for decreasing inter-plate distance. Our results could be relevant in those applications where water is in contact with nanostructured carbon materials at ambient or cryogenic temperatures, as in man-made superhydrophobic materials or filtration membranes, or in techniques that take advantage of hydrated graphene interfaces, as in aqueous electron cryomicroscopy for the analysis of proteins adsorbed on graphene. Full article
(This article belongs to the Special Issue Nonequilibrium Phenomena in Confined Systems)
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2828 KiB  
Article
Permutation Entropy: New Ideas and Challenges
by Karsten Keller, Teresa Mangold, Inga Stolz and Jenna Werner
Entropy 2017, 19(3), 134; https://doi.org/10.3390/e19030134 - 21 Mar 2017
Cited by 65 | Viewed by 11985
Abstract
Over recent years, some new variants of Permutation entropy have been introduced and applied to EEG analysis, including a conditional variant and variants using some additional metric information or being based on entropies that are different from the Shannon entropy. In some situations, [...] Read more.
Over recent years, some new variants of Permutation entropy have been introduced and applied to EEG analysis, including a conditional variant and variants using some additional metric information or being based on entropies that are different from the Shannon entropy. In some situations, it is not completely clear what kind of information the new measures and their algorithmic implementations provide. We discuss the new developments and illustrate them for EEG data. Full article
(This article belongs to the Special Issue Entropy and Electroencephalography II)
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907 KiB  
Article
Spectral Entropy Parameters during Rapid Ventricular Pacing for Transcatheter Aortic Valve Implantation
by Tadeusz Musialowicz, Antti Valtola, Mikko Hippeläinen, Jari Halonen and Pasi Lahtinen
Entropy 2017, 19(3), 133; https://doi.org/10.3390/e19030133 - 20 Mar 2017
Cited by 1 | Viewed by 5469
Abstract
The time-frequency balanced spectral entropy of the EEG is a monitoring technique measuring the level of hypnosis during general anesthesia. Two components of spectral entropy are calculated: state entropy (SE) and response entropy (RE). Transcatheter aortic valve implantation (TAVI) is a less invasive [...] Read more.
The time-frequency balanced spectral entropy of the EEG is a monitoring technique measuring the level of hypnosis during general anesthesia. Two components of spectral entropy are calculated: state entropy (SE) and response entropy (RE). Transcatheter aortic valve implantation (TAVI) is a less invasive treatment for patients suffering from symptomatic aortic stenosis with contraindications for open heart surgery. The goal of hemodynamic management during the procedure is to achieve hemodynamic stability with exact blood pressure control and use of rapid ventricular pacing (RVP) that result in severe hypotension. The objective of this study was to examine how the spectral entropy values respond to RVP and other critical events during the TAVI procedure. Twenty one patients undergoing general anesthesia for TAVI were evaluated. The RVP was used twice during the procedure at a rate of 185 ± 9/min with durations of 16 ± 4 s (range 8–22 s) and 24 ± 6 s (range 18–39 s). The systolic blood pressure during RVP was under 50 ± 5 mmHg. Spectral entropy values SE were significantly declined during the RVP procedure, from 28 ± 13 to 23 ± 13 (p < 0.003) and from 29 ± 12 to 24 ± 10 (p < 0.001). The corresponding values for RE were 29 ± 13 vs. 24 ± 13 (p < 0.006) and 30 ± 12 vs. 25 ± 10 (p < 0.001). Both SE and RE values returned to the pre-RVP values after 1 min. Ultra-short hypotension during RVP changed the spectral entropy parameters, however these indices reverted rapidly to the same value before application of RVP. Full article
(This article belongs to the Special Issue Entropy and Electroencephalography II)
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1498 KiB  
Article
Discrepancies between Conventional Multiscale Entropy and Modified Short-Time Multiscale Entropy of Photoplethysmographic Pulse Signals in Middle- and Old- Aged Individuals with or without Diabetes
by Gen-Min Lin, Bagus Haryadi, Chieh-Ming Yang, Shiao-Chiang Chu, Cheng-Chan Yang and Hsien-Tsai Wu
Entropy 2017, 19(3), 132; https://doi.org/10.3390/e19030132 - 18 Mar 2017
Cited by 12 | Viewed by 4705
Abstract
Multiscale entropy (MSE) of physiological signals may reflect cardiovascular health in diabetes. The classic MSE (cMSE) algorithm requires more than 750 signals for the calculations. The modified short-time MSE (sMSE) may have inconsistent outcomes compared with the cMSE at large time scales and [...] Read more.
Multiscale entropy (MSE) of physiological signals may reflect cardiovascular health in diabetes. The classic MSE (cMSE) algorithm requires more than 750 signals for the calculations. The modified short-time MSE (sMSE) may have inconsistent outcomes compared with the cMSE at large time scales and in a disease status. Therefore, we compared the cMSE of 1500 (cMSE1500) consecutive and 1000 photoplethysmographic (PPG) pulse amplitudes with the sMSE of 500 PPG (sMSE500) pulse amplitudes of bilateral fingertips among middle- to old-aged individuals with or without type 2 diabetes. We discovered that cMSE1500 had the smallest value across scale factors 1–10, followed by cMSE1000, and then sMSE500 in both hands. The cMSE1500, cMSE1000 and sMSE500 did not differ at each scale factor in both hands of persons without diabetes and in the dominant hand of those with diabetes. In contrast, the sMSE500 differed at all scales 1–10 in the non-dominant hand with diabetes. In conclusion, autonomic dysfunction, prevalent in the non-dominant hand which had a low local physical activity in the person with diabetes, might be imprecisely evaluated by the sMSE; therefore, using more PPG signal numbers for the cMSE is preferred in such a situation. Full article
(This article belongs to the Special Issue Entropy and Cardiac Physics II)
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900 KiB  
Article
Information Submanifold Based on SPD Matrices and Its Applications to Sensor Networks
by Hao Xu, Huafei Sun and Aung Naing Win
Entropy 2017, 19(3), 131; https://doi.org/10.3390/e19030131 - 17 Mar 2017
Cited by 1 | Viewed by 4425
Abstract
In this paper, firstly, manifoldPD(n)consisting of alln×nsymmetric positive-definite matrices is introduced based on matrix information geometry; Secondly, the geometrical structures of information submanifold ofPD(n)are presented including metric, [...] Read more.
In this paper, firstly, manifoldPD(n)consisting of alln×nsymmetric positive-definite matrices is introduced based on matrix information geometry; Secondly, the geometrical structures of information submanifold ofPD(n)are presented including metric, geodesic and geodesic distance; Thirdly, the information resolution with sensor networks is presented by three classical measurement models based on information submanifold; Finally, the bearing-only tracking by single sensor is introduced by the Fisher information matrix. The preliminary analysis results introduced in this paper indicate that information submanifold is able to offer consistent and more comprehensive means to understand and solve sensor network problems for targets resolution and tracking, which are not easily handled by some conventional analysis methods. Full article
(This article belongs to the Special Issue Information Geometry II)
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4315 KiB  
Article
Quantitative EEG Markers of Entropy and Auto Mutual Information in Relation to MMSE Scores of Probable Alzheimer’s Disease Patients
by Carmina Coronel, Heinrich Garn, Markus Waser, Manfred Deistler, Thomas Benke, Peter Dal-Bianco, Gerhard Ransmayr, Stephan Seiler, Dieter Grossegger and Reinhold Schmidt
Entropy 2017, 19(3), 130; https://doi.org/10.3390/e19030130 - 17 Mar 2017
Cited by 35 | Viewed by 7053
Abstract
Analysis of nonlinear quantitative EEG (qEEG) markers describing complexity of signal in relation to severity of Alzheimer’s disease (AD) was the focal point of this study. In this study, 79 patients diagnosed with probable AD were recruited from the multi-centric Prospective Dementia Database [...] Read more.
Analysis of nonlinear quantitative EEG (qEEG) markers describing complexity of signal in relation to severity of Alzheimer’s disease (AD) was the focal point of this study. In this study, 79 patients diagnosed with probable AD were recruited from the multi-centric Prospective Dementia Database Austria (PRODEM). EEG recordings were done with the subjects seated in an upright position in a resting state with their eyes closed. Models of linear regressions explaining disease severity, expressed in Mini Mental State Examination (MMSE) scores, were analyzed by the nonlinear qEEG markers of auto mutual information (AMI), Shannon entropy (ShE), Tsallis entropy (TsE), multiscale entropy (MsE), or spectral entropy (SpE), with age, duration of illness, and years of education as co-predictors. Linear regression models with AMI were significant for all electrode sites and clusters, where R 2 is 0.46 at the electrode site C3, 0.43 at Cz, F3, and central region, and 0.42 at the left region. MsE also had significant models at C3 with R 2 > 0.40 at scales τ = 5 and τ = 6 . ShE and TsE also have significant models at T7 and F7 with R 2 > 0.30 . Reductions in complexity, calculated by AMI, SpE, and MsE, were observed as the MMSE score decreased. Full article
(This article belongs to the Special Issue Entropy and Electroencephalography II)
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889 KiB  
Article
Distance-Based Lempel–Ziv Complexity for the Analysis of Electroencephalograms in Patients with Alzheimer’s Disease
by Samantha Simons and Daniel Abásolo
Entropy 2017, 19(3), 129; https://doi.org/10.3390/e19030129 - 17 Mar 2017
Cited by 29 | Viewed by 5491
Abstract
The analysis of electroencephalograms (EEGs) of patients with Alzheimer’s disease (AD) could contribute to the diagnosis of this dementia. In this study, a new non-linear signal processing metric, distance-based Lempel–Ziv complexity (dLZC), is introduced to characterise changes between pairs of electrodes in EEGs [...] Read more.
The analysis of electroencephalograms (EEGs) of patients with Alzheimer’s disease (AD) could contribute to the diagnosis of this dementia. In this study, a new non-linear signal processing metric, distance-based Lempel–Ziv complexity (dLZC), is introduced to characterise changes between pairs of electrodes in EEGs in AD. When complexity in each signal arises from different sub-sequences, dLZC would be greater than when similar sub-sequences are present in each signal. EEGs from 11 AD patients and 11 age-matched control subjects were analysed. The dLZC values for AD patients were lower than for control subjects for most electrode pairs, with statistically significant differences (p < 0.01, Student’s t-test) in 17 electrode pairs in the distant left, local posterior left, and interhemispheric regions. Maximum diagnostic accuracies with leave-one-out cross-validation were 77.27% for subject-based classification and 78.25% for epoch-based classification. These findings suggest not only that EEGs from AD patients are less complex than those from controls, but also that the richness of the information contained in pairs of EEGs from patients is also lower than in age-matched controls. The analysis of EEGs in AD with dLZC may increase the insight into brain dysfunction, providing complementary information to that obtained with other complexity and synchrony methods. Full article
(This article belongs to the Special Issue Symbolic Entropy Analysis and Its Applications)
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890 KiB  
Article
Pairs Generating as a Consequence of the Fractal Entropy: Theory and Applications
by Alexandru Grigorovici, Elena Simona Bacaita, Viorel Puiu Paun, Constantin Grecea, Irina Butuc, Maricel Agop and Ovidiu Popa
Entropy 2017, 19(3), 128; https://doi.org/10.3390/e19030128 - 17 Mar 2017
Cited by 9 | Viewed by 4515
Abstract
In classical concepts, theoretical models are built assuming that the dynamics of the complex system’s stuctural units occur on continuous and differentiable motion variables. In reality, the dynamics of the natural complex systems are much more complicated. These difficulties can be overcome in [...] Read more.
In classical concepts, theoretical models are built assuming that the dynamics of the complex system’s stuctural units occur on continuous and differentiable motion variables. In reality, the dynamics of the natural complex systems are much more complicated. These difficulties can be overcome in a complementary approach, using the fractal concept and the corresponding non-differentiable theoretical model, such as the scale relativity theory or the extended scale relativity theory. Thus, using the last theory, fractal entropy through non-differentiable Lie groups was established and, moreover, the pairs generating mechanisms through fractal entanglement states were explained. Our model has implications in the dynamics of biological structures, in the form of the “chameleon-like” behavior of cholesterol. Full article
(This article belongs to the Special Issue Symbolic Entropy Analysis and Its Applications)
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359 KiB  
Article
Fractional Jensen–Shannon Analysis of the Scientific Output of Researchers in Fractional Calculus
by José A. Tenreiro Machado and António Mendes Lopes
Entropy 2017, 19(3), 127; https://doi.org/10.3390/e19030127 - 17 Mar 2017
Cited by 23 | Viewed by 4906
Abstract
This paper analyses the citation profiles of researchers in fractional calculus. Different metrics are used to quantify the dissimilarities between the data, namely the Canberra distance, and the classical and the generalized (fractional) Jensen–Shannon divergence. The information is then visualized by means of [...] Read more.
This paper analyses the citation profiles of researchers in fractional calculus. Different metrics are used to quantify the dissimilarities between the data, namely the Canberra distance, and the classical and the generalized (fractional) Jensen–Shannon divergence. The information is then visualized by means of multidimensional scaling and hierarchical clustering. The mathematical tools and metrics allow for direct comparison and visualization of researchers based on their relative positioning and on patterns displayed in two- or three-dimensional maps. Full article
(This article belongs to the Special Issue Complex Systems and Fractional Dynamics)
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3239 KiB  
Article
Friction, Free Axes of Rotation and Entropy
by Alexander Kazachkov, Victor Multanen, Viktor Danchuk, Mark Frenkel and Edward Bormashenko
Entropy 2017, 19(3), 123; https://doi.org/10.3390/e19030123 - 17 Mar 2017
Cited by 4 | Viewed by 5273
Abstract
Friction forces acting on rotators may promote their alignment and therefore eliminate degrees of freedom in their movement. The alignment of rotators by friction force was shown by experiments performed with different spinners, demonstrating how friction generates negentropy in a system of rotators. [...] Read more.
Friction forces acting on rotators may promote their alignment and therefore eliminate degrees of freedom in their movement. The alignment of rotators by friction force was shown by experiments performed with different spinners, demonstrating how friction generates negentropy in a system of rotators. A gas of rigid rotators influenced by friction force is considered. The orientational negentropy generated by a friction force was estimated with the Sackur-Tetrode equation. The minimal change in total entropy of a system of rotators, corresponding to their eventual alignment, decreases with temperature. The reported effect may be of primary importance for the phase equilibrium and motion of ubiquitous colloidal and granular systems. Full article
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282 KiB  
Article
Identity Based Generalized Signcryption Scheme in the Standard Model
by Xiaoqin Shen, Yang Ming and Jie Feng
Entropy 2017, 19(3), 121; https://doi.org/10.3390/e19030121 - 17 Mar 2017
Cited by 11 | Viewed by 3991
Abstract
Generalized signcryption (GSC) can adaptively work as an encryption scheme, a signature scheme or a signcryption scheme with only one algorithm. It is more suitable for the storage constrained setting. In this paper, motivated by Paterson–Schuldt’s scheme, based on bilinear pairing, we first [...] Read more.
Generalized signcryption (GSC) can adaptively work as an encryption scheme, a signature scheme or a signcryption scheme with only one algorithm. It is more suitable for the storage constrained setting. In this paper, motivated by Paterson–Schuldt’s scheme, based on bilinear pairing, we first proposed an identity based generalized signcryption (IDGSC) scheme in the standard model. To the best of our knowledge, it is the first scheme that is proven secure in the standard model. Full article
(This article belongs to the Section Information Theory, Probability and Statistics)
244 KiB  
Article
Nonequilibrium Thermodynamics and Scale Invariance
by Leonid M. Martyushev and Vladimir Celezneff
Entropy 2017, 19(3), 126; https://doi.org/10.3390/e19030126 - 16 Mar 2017
Cited by 5 | Viewed by 4432
Abstract
A variant of continuous nonequilibrium thermodynamic theory based on the postulate of the scale invariance of the local relation between generalized fluxes and forces is proposed here. This single postulate replaces the assumptions on local equilibrium and on the known relation between thermodynamic [...] Read more.
A variant of continuous nonequilibrium thermodynamic theory based on the postulate of the scale invariance of the local relation between generalized fluxes and forces is proposed here. This single postulate replaces the assumptions on local equilibrium and on the known relation between thermodynamic fluxes and forces, which are widely used in classical nonequilibrium thermodynamics. It is shown here that such a modification not only makes it possible to deductively obtain the main results of classical linear nonequilibrium thermodynamics, but also provides evidence for a number of statements for a nonlinear case (the maximum entropy production principle, the macroscopic reversibility principle, and generalized reciprocity relations) that are under discussion in the literature. Full article
(This article belongs to the Section Thermodynamics)
446 KiB  
Article
Packer Detection for Multi-Layer Executables Using Entropy Analysis
by Munkhbayar Bat-Erdene, Taebeom Kim, Hyundo Park and Heejo Lee
Entropy 2017, 19(3), 125; https://doi.org/10.3390/e19030125 - 16 Mar 2017
Cited by 23 | Viewed by 8941
Abstract
Packing algorithms are broadly used to avoid anti-malware systems, and the proportion of packed malware has been growing rapidly. However, just a few studies have been conducted on detection various types of packing algorithms in a systemic way. Following this understanding, we elaborate [...] Read more.
Packing algorithms are broadly used to avoid anti-malware systems, and the proportion of packed malware has been growing rapidly. However, just a few studies have been conducted on detection various types of packing algorithms in a systemic way. Following this understanding, we elaborate a method to classify packing algorithms of a given executable into three categories: single-layer packing, re-packing, or multi-layer packing. We convert entropy values of the executable file loaded into memory into symbolic representations, for which we used SAX (Symbolic Aggregate Approximation). Based on experiments of 2196 programs and 19 packing algorithms, we identify that precision (97.7%), accuracy (97.5%), and recall ( 96.8%) of our method are respectively high to confirm that entropy analysis is applicable in identifying packing algorithms. Full article
(This article belongs to the Special Issue Symbolic Entropy Analysis and Its Applications)
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817 KiB  
Article
Witnessing Multipartite Entanglement by Detecting Asymmetry
by Davide Girolami and Benjamin Yadin
Entropy 2017, 19(3), 124; https://doi.org/10.3390/e19030124 - 16 Mar 2017
Cited by 40 | Viewed by 5066
Abstract
The characterization of quantum coherence in the context of quantum information theory and its interplay with quantum correlations is currently subject of intense study. Coherence in a Hamiltonian eigenbasis yields asymmetry, the ability of a quantum system to break a dynamical symmetry generated [...] Read more.
The characterization of quantum coherence in the context of quantum information theory and its interplay with quantum correlations is currently subject of intense study. Coherence in a Hamiltonian eigenbasis yields asymmetry, the ability of a quantum system to break a dynamical symmetry generated by the Hamiltonian. We here propose an experimental strategy to witness multipartite entanglement in many-body systems by evaluating the asymmetry with respect to an additive Hamiltonian. We test our scheme by simulating asymmetry and entanglement detection in a three-qubit Greenberger–Horne–Zeilinger (GHZ) diagonal state. Full article
(This article belongs to the Special Issue Information Geometry II)
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6948 KiB  
Article
On Hölder Projective Divergences
by Frank Nielsen, Ke Sun and Stéphane Marchand-Maillet
Entropy 2017, 19(3), 122; https://doi.org/10.3390/e19030122 - 16 Mar 2017
Cited by 16 | Viewed by 6288
Abstract
We describe a framework to build distances by measuring the tightness of inequalities and introduce the notion of proper statistical divergences and improper pseudo-divergences. We then consider the Hölder ordinary and reverse inequalities and present two novel classes of Hölder divergences and pseudo-divergences [...] Read more.
We describe a framework to build distances by measuring the tightness of inequalities and introduce the notion of proper statistical divergences and improper pseudo-divergences. We then consider the Hölder ordinary and reverse inequalities and present two novel classes of Hölder divergences and pseudo-divergences that both encapsulate the special case of the Cauchy–Schwarz divergence. We report closed-form formulas for those statistical dissimilarities when considering distributions belonging to the same exponential family provided that the natural parameter space is a cone (e.g., multivariate Gaussians) or affine (e.g., categorical distributions). Those new classes of Hölder distances are invariant to rescaling and thus do not require distributions to be normalized. Finally, we show how to compute statistical Hölder centroids with respect to those divergences and carry out center-based clustering toy experiments on a set of Gaussian distributions which demonstrate empirically that symmetrized Hölder divergences outperform the symmetric Cauchy–Schwarz divergence. Full article
(This article belongs to the Special Issue Information Geometry II)
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300 KiB  
Article
Variational Principle for Relative Tail Pressure
by Xianfeng Ma and Ercai Chen
Entropy 2017, 19(3), 120; https://doi.org/10.3390/e19030120 - 15 Mar 2017
Cited by 2 | Viewed by 3534
Abstract
We introduce the relative tail pressure to establish a variational principle for continuous bundle random dynamical systems. We also show that the relative tail pressure is conserved by the principal extension. Full article
(This article belongs to the Special Issue Entropic Properties of Dynamical Systems)
2904 KiB  
Article
Thermoeconomic Optimization of an Irreversible Novikov Plant Model under Different Regimes of Performance
by Juan Carlos Pacheco-Paez, Fernando Angulo-Brown and Marco Antonio Barranco-Jiménez
Entropy 2017, 19(3), 118; https://doi.org/10.3390/e19030118 - 15 Mar 2017
Cited by 13 | Viewed by 4054
Abstract
The so-called Novikov power plant model has been widely used to represent some actual power plants, such as nuclear electric power generators. In the present work, a thermo-economic study of a Novikov power plant model is presented under three different regimes of performance: [...] Read more.
The so-called Novikov power plant model has been widely used to represent some actual power plants, such as nuclear electric power generators. In the present work, a thermo-economic study of a Novikov power plant model is presented under three different regimes of performance: maximum power (MP), maximum ecological function (ME) and maximum efficient power (EP). In this study, different heat transfer laws are used: The Newton’s law of cooling, the Stefan–Boltzmann radiation law, the Dulong–Petit’s law and another phenomenological heat transfer law. For the thermoeconomic optimization of power plant models, a benefit function defined as the quotient of an objective function and the total economical costs is commonly employed. Usually, the total costs take into account two contributions: a cost related to the investment and another stemming from the fuel consumption. In this work, a new cost associated to the maintenance of the power plant is also considered. With these new total costs, it is shown that under the maximum ecological function regime the plant improves its economic and energetic performance in comparison with the other two regimes. The methodology used in this paper is within the context of finite-time thermodynamics. Full article
(This article belongs to the Section Thermodynamics)
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353 KiB  
Letter
Specific Emitter Identification Based on the Natural Measure
by Yongqiang Jia, Shengli Zhu and Lu Gan
Entropy 2017, 19(3), 117; https://doi.org/10.3390/e19030117 - 15 Mar 2017
Cited by 15 | Viewed by 5127
Abstract
Specific emitter identification (SEI) techniques are often used in civilian and military spectrum-management operations, and they are also applied to support the security and authentication of wireless communication. In this letter, a new SEI method based on the natural measure of the one-dimensional [...] Read more.
Specific emitter identification (SEI) techniques are often used in civilian and military spectrum-management operations, and they are also applied to support the security and authentication of wireless communication. In this letter, a new SEI method based on the natural measure of the one-dimensional component of the chaotic system is proposed. We find that the natural measures of the one-dimensional components of higher dimensional systems exist and that they are quite diverse for different systems. Based on this principle, the natural measure is used as an RF fingerprint in this letter. The natural measure can solve the problems caused by a small amount of data and a low sample rate. The Kullback–Leibler divergence is used to quantify the difference between the natural measures obtained from diverse emitters and classify them. The data obtained from real application are exploited to test the validity of the proposed method. Experimental results show that the proposed method is not only easy to operate, but also quite effective, even though the amount of data is small and the sample rate is low. Full article
(This article belongs to the Section Information Theory, Probability and Statistics)
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3458 KiB  
Article
Fluctuation-Driven Transport in Biological Nanopores. A 3D Poisson–Nernst–Planck Study
by Marcel Aguilella-Arzo, María Queralt-Martín, María-Lidón Lopez and Antonio Alcaraz
Entropy 2017, 19(3), 116; https://doi.org/10.3390/e19030116 - 14 Mar 2017
Cited by 8 | Viewed by 5730
Abstract
Living systems display a variety of situations in which non-equilibrium fluctuations couple to certain protein functions yielding astonishing results. Here we study the bacterial channel OmpF under conditions similar to those met in vivo, where acidic resistance mechanisms are known to yield oscillations [...] Read more.
Living systems display a variety of situations in which non-equilibrium fluctuations couple to certain protein functions yielding astonishing results. Here we study the bacterial channel OmpF under conditions similar to those met in vivo, where acidic resistance mechanisms are known to yield oscillations in the electric potential across the cell membrane. We use a three-dimensional structure-based theoretical approach to assess the possibility of obtaining fluctuation-driven transport. Our calculations show that remarkably high voltages would be necessary to observe the actual transport of ions against their concentration gradient. The reasons behind this are the mild selectivity of this bacterial pore and the relatively low efficiencies of the oscillating signals characteristic of membrane cells (random telegraph noise and thermal noise). Full article
(This article belongs to the Special Issue Nonequilibrium Phenomena in Confined Systems)
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5358 KiB  
Article
A Model of Mechanothermodynamic Entropy in Tribology
by Leonid A. Sosnovskiy and Sergei S. Sherbakov
Entropy 2017, 19(3), 115; https://doi.org/10.3390/e19030115 - 14 Mar 2017
Cited by 31 | Viewed by 5119
Abstract
A brief analysis of entropy concepts in continuum mechanics and thermodynamics is presented. The methods of accounting for friction, wear and fatigue processes in the calculation of the thermodynamic entropy are described. It is shown that these and other damage processes of solids [...] Read more.
A brief analysis of entropy concepts in continuum mechanics and thermodynamics is presented. The methods of accounting for friction, wear and fatigue processes in the calculation of the thermodynamic entropy are described. It is shown that these and other damage processes of solids are more adequately described by tribo-fatigue entropy. It was established that mechanothermodynamic entropy calculated as the sum of interacting thermodynamic and tribo-fatigue entropy components has the most general character. Examples of usage (application) of tribo-fatigue and mechanothermodynamic entropies for practical analysis of wear and fatigue processes are given. Full article
(This article belongs to the Special Issue Entropy Application in Tribology)
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1094 KiB  
Article
Recoverable Random Numbers in an Internet of Things Operating System
by Taeill Yoo, Ju-Sung Kang and Yongjin Yeom
Entropy 2017, 19(3), 113; https://doi.org/10.3390/e19030113 - 13 Mar 2017
Cited by 8 | Viewed by 6426
Abstract
Over the past decade, several security issues with Linux Random Number Generator (LRNG) on PCs and Androids have emerged. The main problem involves the process of entropy harvesting, particularly at boot time. An entropy source in the input pool of LRNG is not [...] Read more.
Over the past decade, several security issues with Linux Random Number Generator (LRNG) on PCs and Androids have emerged. The main problem involves the process of entropy harvesting, particularly at boot time. An entropy source in the input pool of LRNG is not transferred into the non-blocking output pool if the entropy counter of the input pool is less than 192 bits out of 4098 bits. Because the entropy estimation of LRNG is highly conservative, the process may require more than one minute for starting the transfer. Furthermore, the design principle of the estimation algorithm is not only heuristic but also unclear. Recently, Google released an Internet of Things (IoT) operating system called Brillo based on the Linux kernel. We analyze the behavior of the random number generator in Brillo, which inherits that of LRNG. In the results, we identify two features that enable recovery of random numbers. With these features, we demonstrate that random numbers of 700 bytes at boot time can be recovered with the success probability of 90% by using time complexity for 5.20 × 2 40 trials. Therefore, the entropy of random numbers of 700 bytes is merely about 43 bits. Since the initial random numbers are supposed to be used for sensitive security parameters, such as stack canary and key derivation, our observation can be applied to practical attacks against cryptosystem. Full article
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836 KiB  
Article
Quantum Probabilities as Behavioral Probabilities
by Vyacheslav I. Yukalov and Didier Sornette
Entropy 2017, 19(3), 112; https://doi.org/10.3390/e19030112 - 13 Mar 2017
Cited by 29 | Viewed by 5943
Abstract
We demonstrate that behavioral probabilities of human decision makers share many common features with quantum probabilities. This does not imply that humans are some quantum objects, but just shows that the mathematics of quantum theory is applicable to the description of human decision [...] Read more.
We demonstrate that behavioral probabilities of human decision makers share many common features with quantum probabilities. This does not imply that humans are some quantum objects, but just shows that the mathematics of quantum theory is applicable to the description of human decision making. The applicability of quantum rules for describing decision making is connected with the nontrivial process of making decisions in the case of composite prospects under uncertainty. Such a process involves deliberations of a decision maker when making a choice. In addition to the evaluation of the utilities of considered prospects, real decision makers also appreciate their respective attractiveness. Therefore, human choice is not based solely on the utility of prospects, but includes the necessity of resolving the utility-attraction duality. In order to justify that human consciousness really functions similarly to the rules of quantum theory, we develop an approach defining human behavioral probabilities as the probabilities determined by quantum rules. We show that quantum behavioral probabilities of humans do not merely explain qualitatively how human decisions are made, but they predict quantitative values of the behavioral probabilities. Analyzing a large set of empirical data, we find good quantitative agreement between theoretical predictions and observed experimental data. Full article
(This article belongs to the Special Issue Foundations of Quantum Mechanics)
342 KiB  
Article
The Two-Time Interpretation and Macroscopic Time-Reversibility
by Yakir Aharonov, Eliahu Cohen and Tomer Landsberger
Entropy 2017, 19(3), 111; https://doi.org/10.3390/e19030111 - 12 Mar 2017
Cited by 35 | Viewed by 8118
Abstract
The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming that unlike the thermodynamic arrow of time, it can lead to reversible dynamics [...] Read more.
The two-state vector formalism motivates a time-symmetric interpretation of quantum mechanics that entails a resolution of the measurement problem. We revisit a post-selection-assisted collapse model previously suggested by us, claiming that unlike the thermodynamic arrow of time, it can lead to reversible dynamics at the macroscopic level. In addition, the proposed scheme enables us to characterize the classical-quantum boundary. We discuss the limitations of this approach and its broad implications for other areas of physics. Full article
(This article belongs to the Special Issue Limits to the Second Law of Thermodynamics: Experiment and Theory)
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681 KiB  
Article
The Gibbs Paradox, the Landauer Principle and the Irreversibility Associated with Tilted Observers
by Luis Herrera
Entropy 2017, 19(3), 110; https://doi.org/10.3390/e19030110 - 11 Mar 2017
Cited by 35 | Viewed by 4574
Abstract
It is well known that, in the context of General Relativity, some spacetimes, when described by a congruence of comoving observers, may consist of a distribution of a perfect (non–dissipative) fluid, whereas the same spacetime as seen by a “tilted” (Lorentz–boosted) congruence of [...] Read more.
It is well known that, in the context of General Relativity, some spacetimes, when described by a congruence of comoving observers, may consist of a distribution of a perfect (non–dissipative) fluid, whereas the same spacetime as seen by a “tilted” (Lorentz–boosted) congruence of observers may exhibit the presence of dissipative processes. As we shall see, the appearance of entropy-producing processes are related to the high dependence of entropy on the specific congruence of observers. This fact is well illustrated by the Gibbs paradox. The appearance of such dissipative processes, as required by the Landauer principle, are necessary in order to erase the different amount of information stored by comoving observers, with respect to tilted ones. Full article
(This article belongs to the Special Issue Advances in Relativistic Statistical Mechanics)
2486 KiB  
Article
Entropy Generation Analysis and Performance Evaluation of Turbulent Forced Convective Heat Transfer to Nanofluids
by Yu Ji, Hao-Chun Zhang, Xie Yang and Lei Shi
Entropy 2017, 19(3), 108; https://doi.org/10.3390/e19030108 - 11 Mar 2017
Cited by 55 | Viewed by 8101
Abstract
The entropy generation analysis of fully turbulent convective heat transfer to nanofluids in a circular tube is investigated numerically using the Reynolds Averaged Navier–Stokes (RANS) model. The nanofluids with particle concentration of 0%, 1%, 2%, 4% and 6% are treated as single phases [...] Read more.
The entropy generation analysis of fully turbulent convective heat transfer to nanofluids in a circular tube is investigated numerically using the Reynolds Averaged Navier–Stokes (RANS) model. The nanofluids with particle concentration of 0%, 1%, 2%, 4% and 6% are treated as single phases of effective properties. The uniform heat flux is enforced at the tube wall. To confirm the validity of the numerical approach, the results have been compared with empirical correlations and analytical formula. The self-similarity profiles of local entropy generation are also studied, in which the peak values of entropy generation by direct dissipation, turbulent dissipation, mean temperature gradients and fluctuating temperature gradients for different Reynolds number as well as different particle concentration are observed. In addition, the effects of Reynolds number, volume fraction of nanoparticles and heat flux on total entropy generation and Bejan number are discussed. In the results, the intersection points of total entropy generation for water and four nanofluids are observed, when the entropy generation decrease before the intersection and increase after the intersection as the particle concentration increases. Finally, by definition of Ep, which combines the first law and second law of thermodynamics and attributed to evaluate the real performance of heat transfer processes, the optimal Reynolds number Reop corresponding to the best performance and the advisable Reynolds number Read providing the appropriate Reynolds number range for nanofluids in convective heat transfer can be determined. Full article
(This article belongs to the Special Issue Entropy in Computational Fluid Dynamics)
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1862 KiB  
Article
Formulation of Exergy Cost Analysis to Graph-Based Thermal Network Models
by Stefano Coss, Elisa Guelpa, Etienne Letournel, Olivier Le-Corre and Vittorio Verda
Entropy 2017, 19(3), 109; https://doi.org/10.3390/e19030109 - 10 Mar 2017
Cited by 9 | Viewed by 4730
Abstract
Information from exergy cost analysis can be effectively used in the design and management of modern district heating networks (DHNs) since it allows to properly account for the irreversibilities in energy conversion and distribution. Nevertheless, this requires the development of suitable graph-based approaches [...] Read more.
Information from exergy cost analysis can be effectively used in the design and management of modern district heating networks (DHNs) since it allows to properly account for the irreversibilities in energy conversion and distribution. Nevertheless, this requires the development of suitable graph-based approaches that are able to effectively consider the network topology and the variations of the physical properties of the heating fluid on a time-dependent basis. In this work, a formulation of exergetic costs suitable for large graph-based networks is proposed, which is consistent with the principles of exergetic costing. In particular, the approach is more compact in comparison to straightforward approaches of exergetic cost formulation available in the literature, especially when applied to fluid networks. Moreover, the proposed formulation is specifically considering transient operating conditions, which is a crucial feature and a necessity for the analysis of future DHNs. Results show that transient effects of the thermodynamic behavior are not negligible for exergy cost analysis, while this work offers a coherent approach to quantify them. Full article
(This article belongs to the Special Issue Thermoeconomics for Energy Efficiency)
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3660 KiB  
Article
Physical Intelligence and Thermodynamic Computing
by Robert L. Fry
Entropy 2017, 19(3), 107; https://doi.org/10.3390/e19030107 - 9 Mar 2017
Cited by 14 | Viewed by 8837
Abstract
This paper proposes that intelligent processes can be completely explained by thermodynamic principles. They can equally be described by information-theoretic principles that, from the standpoint of the required optimizations, are functionally equivalent. The underlying theory arises from two axioms regarding distinguishability and causality. [...] Read more.
This paper proposes that intelligent processes can be completely explained by thermodynamic principles. They can equally be described by information-theoretic principles that, from the standpoint of the required optimizations, are functionally equivalent. The underlying theory arises from two axioms regarding distinguishability and causality. Their consequence is a theory of computation that applies to the only two kinds of physical processes possible—those that reconstruct the past and those that control the future. Dissipative physical processes fall into the first class, whereas intelligent ones comprise the second. The first kind of process is exothermic and the latter is endothermic. Similarly, the first process dumps entropy and energy to its environment, whereas the second reduces entropy while requiring energy to operate. It is shown that high intelligence efficiency and high energy efficiency are synonymous. The theory suggests the usefulness of developing a new computing paradigm called Thermodynamic Computing to engineer intelligent processes. The described engineering formalism for the design of thermodynamic computers is a hybrid combination of information theory and thermodynamics. Elements of the engineering formalism are introduced in the reverse-engineer of a cortical neuron. The cortical neuron provides perhaps the simplest and most insightful example of a thermodynamic computer possible. It can be seen as a basic building block for constructing more intelligent thermodynamic circuits. Full article
(This article belongs to the Special Issue Maximum Entropy and Its Application II)
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233 KiB  
Article
On Quantum Collapse as a Basis for the Second Law of Thermodynamics
by Ruth E. Kastner
Entropy 2017, 19(3), 106; https://doi.org/10.3390/e19030106 - 9 Mar 2017
Cited by 13 | Viewed by 7235
Abstract
It was first suggested by David Z. Albert that the existence of a real, physical non-unitary process (i.e., “collapse”) at the quantum level would yield a complete explanation for the Second Law of Thermodynamics (i.e., the increase in entropy over time). The contribution [...] Read more.
It was first suggested by David Z. Albert that the existence of a real, physical non-unitary process (i.e., “collapse”) at the quantum level would yield a complete explanation for the Second Law of Thermodynamics (i.e., the increase in entropy over time). The contribution of such a process would be to provide a physical basis for the ontological indeterminacy needed to derive the irreversible Second Law against a backdrop of otherwise reversible, deterministic physical laws. An alternative understanding of the source of this possible quantum “collapse” or non-unitarity is presented herein, in terms of the Transactional Interpretation (TI). The present model provides a specific physical justification for Boltzmann’s often-criticized assumption of molecular randomness (Stosszahlansatz), thereby changing its status from an ad hoc postulate to a theoretically grounded result, without requiring any change to the basic quantum theory. In addition, it is argued that TI provides an elegant way of reconciling, via indeterministic collapse, the time-reversible Liouville evolution with the time-irreversible evolution inherent in so-called “master equations” that specify the changes in occupation of the various possible states in terms of the transition rates between them. The present model is contrasted with the Ghirardi–Rimini–Weber (GRW) “spontaneous collapse” theory previously suggested for this purpose by Albert. Full article
(This article belongs to the Special Issue Entropy, Time and Evolution)
912 KiB  
Article
Brownian Dynamics Computational Model of Protein Diffusion in Crowded Media with Dextran Macromolecules as Obstacles
by Pablo M. Blanco, Mireia Via, Josep Lluís Garcés, Sergio Madurga and Francesc Mas
Entropy 2017, 19(3), 105; https://doi.org/10.3390/e19030105 - 9 Mar 2017
Cited by 16 | Viewed by 6305
Abstract
The high concentration of macromolecules (i.e., macromolecular crowding) in cellular environments leads to large quantitative effects on the dynamic and equilibrium biological properties. These effects have been experimentally studied using inert macromolecules to mimic a realistic cellular medium. In this paper, two different [...] Read more.
The high concentration of macromolecules (i.e., macromolecular crowding) in cellular environments leads to large quantitative effects on the dynamic and equilibrium biological properties. These effects have been experimentally studied using inert macromolecules to mimic a realistic cellular medium. In this paper, two different experimental in vitro systems of diffusing proteins which use dextran macromolecules as obstacles are computationally analyzed. A new model for dextran macromolecules based on effective radii accounting for macromolecular compression induced by crowding is proposed. The obtained results for the diffusion coefficient and the anomalous diffusion exponent exhibit good qualitative and generally good quantitative agreement with experiments. Volume fraction and hydrodynamic interactions are found to be crucial to describe the diffusion coefficient decrease in crowded media. However, no significant influence of the hydrodynamic interactions in the anomalous diffusion exponent is found. Full article
(This article belongs to the Special Issue Nonequilibrium Phenomena in Confined Systems)
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976 KiB  
Article
Complexity and Vulnerability Analysis of the C. Elegans Gap Junction Connectome
by James M. Kunert-Graf, Nikita A. Sakhanenko and David J. Galas
Entropy 2017, 19(3), 104; https://doi.org/10.3390/e19030104 - 8 Mar 2017
Cited by 4 | Viewed by 5894
Abstract
We apply a network complexity measure to the gap junction network of the somatic nervous system of C. elegans and find that it possesses a much higher complexity than we might expect from its degree distribution alone. This “excess” complexity is seen to [...] Read more.
We apply a network complexity measure to the gap junction network of the somatic nervous system of C. elegans and find that it possesses a much higher complexity than we might expect from its degree distribution alone. This “excess” complexity is seen to be caused by a relatively small set of connections involving command interneurons. We describe a method which progressively deletes these “complexity-causing” connections, and find that when these are eliminated, the network becomes significantly less complex than a random network. Furthermore, this result implicates the previously-identified set of neurons from the synaptic network’s “rich club” as the structural components encoding the network’s excess complexity. This study and our method thus support a view of the gap junction Connectome as consisting of a rather low-complexity network component whose symmetry is broken by the unique connectivities of singularly important rich club neurons, sharply increasing the complexity of the network. Full article
(This article belongs to the Special Issue Complexity, Criticality and Computation (C³))
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