Next Issue
Previous Issue

E-Mail Alert

Add your e-mail address to receive forthcoming issues of this journal:

Journal Browser

Journal Browser

Table of Contents

Entropy, Volume 18, Issue 10 (October 2016)

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Readerexternal link to open them.
View options order results:
result details:
Displaying articles 1-37
Export citation of selected articles as:
Open AccessArticle A Robust Sparse Adaptive Filtering Algorithm with a Correntropy Induced Metric Constraint for Broadband Multi-Path Channel Estimation
Entropy 2016, 18(10), 380; https://doi.org/10.3390/e18100380
Received: 27 August 2016 / Revised: 15 October 2016 / Accepted: 20 October 2016 / Published: 24 October 2016
Cited by 12 | PDF Full-text (3004 KB) | HTML Full-text | XML Full-text
Abstract
A robust sparse least-mean mixture-norm (LMMN) algorithm is proposed, and its performance is appraised in the context of estimating a broadband multi-path wireless channel. The proposed algorithm is implemented via integrating a correntropy-induced metric (CIM) penalty into the conventional LMMN algorithm to modify
[...] Read more.
A robust sparse least-mean mixture-norm (LMMN) algorithm is proposed, and its performance is appraised in the context of estimating a broadband multi-path wireless channel. The proposed algorithm is implemented via integrating a correntropy-induced metric (CIM) penalty into the conventional LMMN algorithm to modify the basic cost function, which is denoted as the CIM-based LMMN (CIM-LMMN) algorithm. The proposed CIM-LMMN algorithm is derived in detail within the kernel framework. The updating equation of CIM-LMMN can provide a zero attractor to attract the non-dominant channel coefficients to zeros, and it also gives a tradeoff between the sparsity and the estimation misalignment. Moreover, the channel estimation behavior is investigated over a broadband sparse multi-path wireless channel, and the simulation results are compared with the least mean square/fourth (LMS/F), least mean square (LMS), least mean fourth (LMF) and the recently-developed sparse channel estimation algorithms. The channel estimation performance obtained from the designated sparse channel estimation demonstrates that the CIM-LMMN algorithm outperforms the recently-developed sparse LMMN algorithms and the relevant sparse channel estimation algorithms. From the results, we can see that our CIM-LMMN algorithm is robust and is superior to these mentioned algorithms in terms of both the convergence speed rate and the channel estimation misalignment for estimating a sparse channel. Full article
(This article belongs to the Special Issue Maximum Entropy and Its Application II)
Figures

Figure 1

Open AccessArticle A Novel Sequence-Based Feature for the Identification of DNA-Binding Sites in Proteins Using Jensen–Shannon Divergence
Entropy 2016, 18(10), 379; https://doi.org/10.3390/e18100379
Received: 30 July 2016 / Revised: 19 October 2016 / Accepted: 20 October 2016 / Published: 24 October 2016
Cited by 2 | PDF Full-text (1170 KB) | HTML Full-text | XML Full-text
Abstract
The knowledge of protein-DNA interactions is essential to fully understand the molecular activities of life. Many research groups have developed various tools which are either structure- or sequence-based approaches to predict the DNA-binding residues in proteins. The structure-based methods usually achieve good results,
[...] Read more.
The knowledge of protein-DNA interactions is essential to fully understand the molecular activities of life. Many research groups have developed various tools which are either structure- or sequence-based approaches to predict the DNA-binding residues in proteins. The structure-based methods usually achieve good results, but require the knowledge of the 3D structure of protein; while sequence-based methods can be applied to high-throughput of proteins, but require good features. In this study, we present a new information theoretic feature derived from Jensen–Shannon Divergence (JSD) between amino acid distribution of a site and the background distribution of non-binding sites. Our new feature indicates the difference of a certain site from a non-binding site, thus it is informative for detecting binding sites in proteins. We conduct the study with a five-fold cross validation of 263 proteins utilizing the Random Forest classifier. We evaluate the functionality of our new features by combining them with other popular existing features such as position-specific scoring matrix (PSSM), orthogonal binary vector (OBV), and secondary structure (SS). We notice that by adding our features, we can significantly boost the performance of Random Forest classifier, with a clear increment of sensitivity and Matthews correlation coefficient (MCC). Full article
(This article belongs to the Special Issue Entropy on Biosignals and Intelligent Systems)
Figures

Figure 1

Open AccessArticle Second Law Analysis of Nanofluid Flow within a Circular Minichannel Considering Nanoparticle Migration
Entropy 2016, 18(10), 378; https://doi.org/10.3390/e18100378
Received: 19 August 2016 / Revised: 14 October 2016 / Accepted: 18 October 2016 / Published: 21 October 2016
PDF Full-text (7083 KB) | HTML Full-text | XML Full-text
Abstract
In the current research, entropy generation for the water–alumina nanofluid flow is studied in a circular minichannel for the laminar regime under constant wall heat flux in order to evaluate irreversibilities arising from friction and heat transfer. To this end, simulations are carried
[...] Read more.
In the current research, entropy generation for the water–alumina nanofluid flow is studied in a circular minichannel for the laminar regime under constant wall heat flux in order to evaluate irreversibilities arising from friction and heat transfer. To this end, simulations are carried out considering the particle migration effects. Due to particle migration, the nanoparticles incorporate non-uniform distribution at the cross-section of the pipe, such that the concentration is larger at central areas. The concentration non-uniformity increases by augmenting the mean concentration, particle size, and Reynolds number. The rates of entropy generation are evaluated both locally and globally (integrated). The obtained results show that particle migration changes the thermal and frictional entropy generation rates significantly, particularly at high Reynolds numbers, large concentrations, and coarser particles. Hence, this phenomenon should be considered in examinations related to energy in the field of nanofluids. Full article
(This article belongs to the Special Issue Limits to the Second Law of Thermodynamics: Experiment and Theory)
Figures

Figure 1

Open AccessArticle Isothermal Oxidation of Aluminized Coatings on High-Entropy Alloys
Entropy 2016, 18(10), 376; https://doi.org/10.3390/e18100376
Received: 31 July 2016 / Revised: 7 October 2016 / Accepted: 14 October 2016 / Published: 20 October 2016
PDF Full-text (17446 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The isothermal oxidation resistance of Al0.2Co1.5CrFeNi1.5Ti0.3 high-entropy alloy is analyzed and the microstructural evolution of the oxide layer is studied. The limited aluminum, about 3.6 at %, leads to the non-continuous alumina. The present alloy is
[...] Read more.
The isothermal oxidation resistance of Al0.2Co1.5CrFeNi1.5Ti0.3 high-entropy alloy is analyzed and the microstructural evolution of the oxide layer is studied. The limited aluminum, about 3.6 at %, leads to the non-continuous alumina. The present alloy is insufficient for severe circumstances only due to chromium oxide that is 10 μm after 1173 K for 360 h. Thus, the aluminized high-entropy alloys (HEAs) are further prepared by the industrial packing cementation process at 1273 K and 1323 K. The aluminizing coating is 50 μm at 1273 K after 5 h. The coating growth is controlled by the diffusion of aluminum. The interdiffusion zone reveals two regions that are the Ti-, Co-, Ni-rich area and the Fe-, Cr-rich area. The oxidation resistance of aluminizing HEA improves outstandingly, and sustains at 1173 K and 1273 K for 441 h without any spallation. The alumina at the surface and the stable interface contribute to the performance of this Al0.2Co1.5CrFeNi1.5Ti0.3 alloy. Full article
(This article belongs to the Special Issue High-Entropy Alloys and High-Entropy-Related Materials)
Figures

Figure 1

Open AccessArticle Non-Asymptotic Confidence Sets for Circular Means
Entropy 2016, 18(10), 375; https://doi.org/10.3390/e18100375
Received: 15 July 2016 / Revised: 10 October 2016 / Accepted: 13 October 2016 / Published: 20 October 2016
Cited by 1 | PDF Full-text (345 KB) | HTML Full-text | XML Full-text
Abstract
The mean of data on the unit circle is defined as the minimizer of the average squared Euclidean distance to the data. Based on Hoeffding’s mass concentration inequalities, non-asymptotic confidence sets for circular means are constructed which are universal in the sense that
[...] Read more.
The mean of data on the unit circle is defined as the minimizer of the average squared Euclidean distance to the data. Based on Hoeffding’s mass concentration inequalities, non-asymptotic confidence sets for circular means are constructed which are universal in the sense that they require no distributional assumptions. These are then compared with asymptotic confidence sets in simulations and for a real data set. Full article
(This article belongs to the Special Issue Differential Geometrical Theory of Statistics) Printed Edition available
Figures

Figure 1

Open AccessArticle On the Virtual Cell Transmission in Ultra Dense Networks
Entropy 2016, 18(10), 374; https://doi.org/10.3390/e18100374
Received: 25 June 2016 / Revised: 30 September 2016 / Accepted: 14 October 2016 / Published: 20 October 2016
Cited by 1 | PDF Full-text (4763 KB) | HTML Full-text | XML Full-text
Abstract
Ultra dense networks (UDN) are identified as one of the key enablers for 5G, since they can provide an ultra high spectral reuse factor exploiting proximal transmissions. By densifying the network infrastructure equipment, it is highly possible that each user will have one
[...] Read more.
Ultra dense networks (UDN) are identified as one of the key enablers for 5G, since they can provide an ultra high spectral reuse factor exploiting proximal transmissions. By densifying the network infrastructure equipment, it is highly possible that each user will have one or more dedicated serving base station antennas, introducing the user-centric virtual cell paradigm. However, due to irregular deployment of a large amount of base station antennas, the interference environment becomes rather complex, thus introducing severe interferences among different virtual cells. This paper focuses on the downlink transmission scheme in UDN where a large number of users and base station antennas is uniformly spread over a certain area. An interference graph is first created based on the large-scale fadings to give a potential description of the interference relationship among the virtual cells. Then, base station antennas and users in the virtual cells within the same maximally-connected component are grouped together and merged into one new virtual cell cluster, where users are jointly served via zero-forcing (ZF) beamforming. A multi-virtual-cell minimum mean square error precoding scheme is further proposed to mitigate the inter-cluster interference. Additionally, the interference alignment framework is proposed based on the low complexity virtual cell merging to eliminate the strong interference between different virtual cells. Simulation results show that the proposed interference graph-based virtual cell merging approach can attain the average user spectral efficiency performance of the grouping scheme based on virtual cell overlapping with a smaller virtual cell size and reduced signal processing complexity. Besides, the proposed user-centric transmission scheme greatly outperforms the BS-centric transmission scheme (maximum ratio transmission (MRT)) in terms of both the average user spectral efficiency and edge user spectral efficiency. What is more, interference alignment based on the low complexity virtual cell merging can achieve much better performance than ZF and MRT precoding in terms of average user spectral efficiency. Full article
Figures

Figure 1

Open AccessCorrection Correction: Jacobsen, C.S., et al. Continuous Variable Quantum Key Distribution with a Noisy Laser. Entropy 2015, 17, 4654–4663
Entropy 2016, 18(10), 373; https://doi.org/10.3390/e18100373
Received: 8 October 2016 / Accepted: 14 October 2016 / Published: 20 October 2016
PDF Full-text (1337 KB) | HTML Full-text | XML Full-text Figures

Figure 1

Open AccessArticle Point Information Gain and Multidimensional Data Analysis
Entropy 2016, 18(10), 372; https://doi.org/10.3390/e18100372
Received: 1 August 2016 / Revised: 17 September 2016 / Accepted: 14 October 2016 / Published: 19 October 2016
Cited by 5 | PDF Full-text (4329 KB) | HTML Full-text | XML Full-text
Abstract
We generalize the point information gain (PIG) and derived quantities, i.e., point information gain entropy (PIE) and point information gain entropy density (PIED), for the case of the Rényi entropy and simulate the behavior of PIG for typical distributions. We also use these
[...] Read more.
We generalize the point information gain (PIG) and derived quantities, i.e., point information gain entropy (PIE) and point information gain entropy density (PIED), for the case of the Rényi entropy and simulate the behavior of PIG for typical distributions. We also use these methods for the analysis of multidimensional datasets. We demonstrate the main properties of PIE/PIED spectra for the real data with the examples of several images and discuss further possible utilizations in other fields of data processing. Full article
(This article belongs to the Section Information Theory)
Figures

Figure 1

Open AccessArticle Study on the Stability and Entropy Complexity of an Energy-Saving and Emission-Reduction Model with Two Delays
Entropy 2016, 18(10), 371; https://doi.org/10.3390/e18100371
Received: 2 August 2016 / Revised: 13 October 2016 / Accepted: 13 October 2016 / Published: 19 October 2016
Cited by 1 | PDF Full-text (7021 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, we build a model of energy-savings and emission-reductions with two delays. In this model, it is assumed that the interaction between energy-savings and emission-reduction and that between carbon emissions and economic growth are delayed. We examine the local stability and
[...] Read more.
In this paper, we build a model of energy-savings and emission-reductions with two delays. In this model, it is assumed that the interaction between energy-savings and emission-reduction and that between carbon emissions and economic growth are delayed. We examine the local stability and the existence of a Hopf bifurcation at the equilibrium point of the system. By employing System Complexity Theory, we also analyze the impact of delays and the feedback control on stability and entropy of the system are analyzed from two aspects: single delay and double delays. In numerical simulation section, we test the theoretical analysis by using means bifurcation diagram, the largest Lyapunov exponent diagrams, attractor, time-domain plot, Poincare section plot, power spectrum, entropy diagram, 3-D surface chart and 4-D graph, the simulation results demonstrating that the inappropriate changes of delays and the feedback control will result in instability and fluctuation of carbon emissions. Finally, the bifurcation control is achieved by using the method of variable feedback control. Hence, we conclude that the greater the value of the control parameter, the better the effect of the bifurcation control. The results will provide for the development of energy-saving and emission-reduction policies. Full article
(This article belongs to the Section Complexity)
Figures

Figure 1

Open AccessFeature PaperArticle From Tools in Symplectic and Poisson Geometry to J.-M. Souriau’s Theories of Statistical Mechanics and Thermodynamics
Entropy 2016, 18(10), 370; https://doi.org/10.3390/e18100370
Received: 28 July 2016 / Revised: 30 September 2016 / Accepted: 5 October 2016 / Published: 19 October 2016
Cited by 3 | PDF Full-text (450 KB) | HTML Full-text | XML Full-text
Abstract
I present in this paper some tools in symplectic and Poisson geometry in view of their applications in geometric mechanics and mathematical physics. After a short discussion of the Lagrangian an Hamiltonian formalisms, including the use of symmetry groups, and a presentation of
[...] Read more.
I present in this paper some tools in symplectic and Poisson geometry in view of their applications in geometric mechanics and mathematical physics. After a short discussion of the Lagrangian an Hamiltonian formalisms, including the use of symmetry groups, and a presentation of the Tulczyjew’s isomorphisms (which explain some aspects of the relations between these formalisms), I explain the concept of manifold of motions of a mechanical system and its use, due to J.-M. Souriau, in statistical mechanics and thermodynamics. The generalization of the notion of thermodynamic equilibrium in which the one-dimensional group of time translations is replaced by a multi-dimensional, maybe non-commutative Lie group, is fully discussed and examples of applications in physics are given. Full article
(This article belongs to the Special Issue Differential Geometrical Theory of Statistics) Printed Edition available
Open AccessArticle Chemical Reactions Using a Non-Equilibrium Wigner Function Approach
Entropy 2016, 18(10), 369; https://doi.org/10.3390/e18100369
Received: 13 July 2016 / Revised: 14 September 2016 / Accepted: 13 October 2016 / Published: 19 October 2016
PDF Full-text (415 KB) | HTML Full-text | XML Full-text
Abstract
A three-dimensional model of binary chemical reactions is studied. We consider an ab initio quantum two-particle system subjected to an attractive interaction potential and to a heat bath at thermal equilibrium at absolute temperature T>0. Under the sole action of
[...] Read more.
A three-dimensional model of binary chemical reactions is studied. We consider an ab initio quantum two-particle system subjected to an attractive interaction potential and to a heat bath at thermal equilibrium at absolute temperature T > 0 . Under the sole action of the attraction potential, the two particles can either be bound or unbound to each other. While at T = 0 , there is no transition between both states, such a transition is possible when T > 0 (due to the heat bath) and plays a key role as k B T approaches the magnitude of the attractive potential. We focus on a quantum regime, typical of chemical reactions, such that: (a) the thermal wavelength is shorter than the range of the attractive potential (lower limit on T) and (b) ( 3 / 2 ) k B T does not exceed the magnitude of the attractive potential (upper limit on T). In this regime, we extend several methods previously applied to analyze the time duration of DNA thermal denaturation. The two-particle system is then described by a non-equilibrium Wigner function. Under Assumptions (a) and (b), and for sufficiently long times, defined by a characteristic time scale D that is subsequently estimated, the general dissipationless non-equilibrium equation for the Wigner function is approximated by a Smoluchowski-like equation displaying dissipation and quantum effects. A comparison with the standard chemical kinetic equations is made. The time τ required for the two particles to transition from the bound state to unbound configurations is studied by means of the mean first passage time formalism. An approximate formula for τ, in terms of D and exhibiting the Arrhenius exponential factor, is obtained. Recombination processes are also briefly studied within our framework and compared with previous well-known methods. Full article
Open AccessArticle A Hydrodynamic Model for Silicon Nanowires Based on the Maximum Entropy Principle
Entropy 2016, 18(10), 368; https://doi.org/10.3390/e18100368
Received: 14 July 2016 / Revised: 6 September 2016 / Accepted: 30 September 2016 / Published: 19 October 2016
Cited by 6 | PDF Full-text (566 KB) | HTML Full-text | XML Full-text
Abstract
Silicon nanowires (SiNW) are quasi-one-dimensional structures in which the electrons are spatially confined in two directions, and they are free to move along the axis of the wire. The spatial confinement is governed by the Schrödinger–Poisson system, which must be coupled to the
[...] Read more.
Silicon nanowires (SiNW) are quasi-one-dimensional structures in which the electrons are spatially confined in two directions, and they are free to move along the axis of the wire. The spatial confinement is governed by the Schrödinger–Poisson system, which must be coupled to the transport in the free motion direction. For devices with the characteristic length of a few tens of nanometers, the transport of the electrons along the axis of the wire can be considered semiclassical, and it can be dealt with by the multi-sub-band Boltzmann transport equations (MBTE). By taking the moments of the MBTE, a hydrodynamic model has been formulated, where explicit closure relations for the fluxes and production terms (i.e., the moments on the collisional operator) are obtained by means of the maximum entropy principle of extended thermodynamics, including the scattering of electrons with phonons, impurities and surface roughness scattering. Numerical results are shown for a SiNW transistor. Full article
(This article belongs to the Special Issue Maximum Entropy Principle and Semiconductors)
Figures

Figure 1

Open AccessArticle Methodology for Simulation and Analysis of Complex Adaptive Supply Network Structure and Dynamics Using Information Theory
Entropy 2016, 18(10), 367; https://doi.org/10.3390/e18100367
Received: 27 July 2016 / Revised: 4 October 2016 / Accepted: 12 October 2016 / Published: 18 October 2016
Cited by 2 | PDF Full-text (2100 KB) | HTML Full-text | XML Full-text
Abstract
Supply networks existing today in many industries can behave as complex adaptive systems making them more difficult to analyze and assess. Being able to fully understand both the complex static and dynamic structures of a complex adaptive supply network (CASN) are key to
[...] Read more.
Supply networks existing today in many industries can behave as complex adaptive systems making them more difficult to analyze and assess. Being able to fully understand both the complex static and dynamic structures of a complex adaptive supply network (CASN) are key to being able to make more informed management decisions and prioritize resources and production throughout the network. Previous efforts to model and analyze CASN have been impeded by the complex, dynamic nature of the systems. However, drawing from other complex adaptive systems sciences, information theory provides a model-free methodology removing many of those barriers, especially concerning complex network structure and dynamics. With minimal information about the network nodes, transfer entropy can be used to reverse engineer the network structure while local transfer entropy can be used to analyze the network structure’s dynamics. Both simulated and real-world networks were analyzed using this methodology. Applying the methodology to CASNs allows the practitioner to capitalize on observations from the highly multidisciplinary field of information theory which provides insights into CASN’s self-organization, emergence, stability/instability, and distributed computation. This not only provides managers with a more thorough understanding of a system’s structure and dynamics for management purposes, but also opens up research opportunities into eventual strategies to monitor and manage emergence and adaption within the environment. Full article
(This article belongs to the Special Issue Transfer Entropy II)
Figures

Figure 1

Open AccessArticle Intelligent Security IT System for Detecting Intruders Based on Received Signal Strength Indicators
Entropy 2016, 18(10), 366; https://doi.org/10.3390/e18100366
Received: 10 September 2016 / Revised: 10 October 2016 / Accepted: 10 October 2016 / Published: 16 October 2016
Cited by 2 | PDF Full-text (4742 KB) | HTML Full-text | XML Full-text
Abstract
Given that entropy-based IT technology has been applied in homes, office buildings and elsewhere for IT security systems, diverse kinds of intelligent services are currently provided. In particular, IT security systems have become more robust and varied. However, access control systems still depend
[...] Read more.
Given that entropy-based IT technology has been applied in homes, office buildings and elsewhere for IT security systems, diverse kinds of intelligent services are currently provided. In particular, IT security systems have become more robust and varied. However, access control systems still depend on tags held by building entrants. Since tags can be obtained by intruders, an approach to counter the disadvantages of tags is required. For example, it is possible to track the movement of tags in intelligent buildings in order to detect intruders. Therefore, each tag owner can be judged by analyzing the movements of their tags. This paper proposes a security approach based on the received signal strength indicators (RSSIs) of beacon-based tags to detect intruders. The normal RSSI patterns of moving entrants are obtained and analyzed. Intruders can be detected when abnormal RSSIs are measured in comparison to normal RSSI patterns. In the experiments, one normal and one abnormal scenario are defined for collecting the RSSIs of a Bluetooth-based beacon in order to validate the proposed method. When the RSSIs of both scenarios are compared to pre-collected RSSIs, the RSSIs of the abnormal scenario are about 61% more different compared to the RSSIs of the normal scenario. Therefore, intruders in buildings can be detected by considering RSSI differences. Full article
Figures

Figure 1

Open AccessArticle Boltzmann Sampling by Degenerate Optical Parametric Oscillator Network for Structure-Based Virtual Screening
Entropy 2016, 18(10), 365; https://doi.org/10.3390/e18100365
Received: 3 September 2016 / Revised: 10 October 2016 / Accepted: 11 October 2016 / Published: 13 October 2016
Cited by 4 | PDF Full-text (984 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A structure-based lead optimization procedure is an essential step to finding appropriate ligand molecules binding to a target protein structure in order to identify drug candidates. This procedure takes a known structure of a protein-ligand complex as input, and structurally similar compounds with
[...] Read more.
A structure-based lead optimization procedure is an essential step to finding appropriate ligand molecules binding to a target protein structure in order to identify drug candidates. This procedure takes a known structure of a protein-ligand complex as input, and structurally similar compounds with the query ligand are designed in consideration with all possible combinations of atomic species. This task is, however, computationally hard since such combinatorial optimization problems belong to the non-deterministic nonpolynomial-time hard (NP-hard) class. In this paper, we propose the structure-based lead generation and optimization procedures by a degenerate optical parametric oscillator (DOPO) network. Results of numerical simulation demonstrate that the DOPO network efficiently identifies a set of appropriate ligand molecules according to the Boltzmann sampling law. Full article
(This article belongs to the collection Quantum Information)
Figures

Figure 1

Back to Top