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1
Korpyś, Mateusz, Anna Gancarczyk, Marzena Iwaniszyn, Katarzyna Sindera, Przemysław J. Jodłowski e Andrzej Kołodziej. "Analysis of Entropy Production in Structured Chemical Reactors: Optimization for Catalytic Combustion of Air Pollutants". Entropy 22, n. 9 (11 settembre 2020): 1017. http://dx.doi.org/10.3390/e22091017.
Abstract (sommario):
Optimization of structured reactors is not without some difficulties due to highly random economic issues. In this study, an entropic approach to optimization is proposed. The model of entropy production in a structured catalytic reactor is introduced and discussed. Entropy production due to flow friction, heat and mass transfer and chemical reaction is derived and referred to the process yield. The entropic optimization criterion is applied for the case of catalytic combustion of methane. Several variants of catalytic supports are considered including wire gauzes, classic (long-channel) and short-channel monoliths, packed bed and solid foam. The proposed entropic criterion may indicate technically rational solutions of a reactor process that is as close as possible to the equilibrium, taking into account all the process phenomena such as heat and mass transfer, flow friction and chemical reaction.
2
Tseng, Chih-Yuan. "Entropic criterion for model selection". Physica A: Statistical Mechanics and its Applications 370, n. 2 (ottobre 2006): 530–38. http://dx.doi.org/10.1016/j.physa.2006.03.024.
3
SU, HONG-YI, JING-LING CHEN, CHUNFENG WU, DONG-LING DENG e C. H. OH. "DETECTING EINSTEIN–PODOLSKY–ROSEN STEERING FOR CONTINUOUS VARIABLE WAVEFUNCTIONS". International Journal of Quantum Information 11, n. 02 (marzo 2013): 1350019. http://dx.doi.org/10.1142/s0219749913500196.
Abstract (sommario):
By use of Reid's criterion and the entropic criterion, we investigate the Einstein–Podolsky–Rosen (EPR) steering for some entangled continuous variable wavefunctions. We find that some entangled states that violate Bell's inequality will not violate Reid's EPR inequality nor the entropic inequality. This implies that neither criterion gives a necessary and sufficient condition to detect the EPR steering.
4
GULKO, LES. "THE ENTROPIC MARKET HYPOTHESIS". International Journal of Theoretical and Applied Finance 02, n. 03 (luglio 1999): 293–329. http://dx.doi.org/10.1142/s0219024999000170.
Abstract (sommario):
Information theory teaches that entropy is the fundamental limit for data compression, and electrical engineers routinely use entropy as a criterion for efficient storage and transmission of information. Since modern financial theory teaches that competitive market prices store and transmit information with some efficiency, should financial economists be concerned with entropy? This paper presents a market model in which entropy emerges endogenously as a condition for the operational efficiency of price discovery while entropy maximization emerges as a condition for the informational efficiency of market prices. The maximum-entropy formalism makes the efficient market hypothesis operational and testable. This formalism is used to establish that entropic markets admit no arbitrage and support both the Ross arbitrage pricing theory and the Black–Scholes stock option pricing model.
5
Sobolev, Sergey L., e Igor V. Kudinov. "Extended Nonequilibrium Variables for 1D Hyperbolic Heat Conduction". Journal of Non-Equilibrium Thermodynamics 45, n. 3 (26 luglio 2020): 209–21. http://dx.doi.org/10.1515/jnet-2019-0076.
Abstract (sommario):
AbstractWe use the Shannon (information) entropy to define an “entropic” temperature for 1D nonequilibrium system with heat flux. In contrast to the kinetic temperature, which is related to the average kinetic energy, the nonequilibrium entropic temperature is related to the changes in entropy and serves as a criterion for thermalization. However, the direction and value of the heat flux is controlled by the gradient of the kinetic temperature, whereas space-time evolution and the space-time evolution of the heat flux are governed by the hyperbolic heat conduction equation. The extended nonequilibrium variables, namely, entropy, entropic temperature, thermal conductivity, and heat capacity demonstrate a third-law-like behavior at high deviation from equilibrium when the heat flux tends to its maximum value, even at nonzero value of the kinetic temperature. The ratio of the heat flux to its maximum possible value plays a role of an order parameter – it varies from zero in the equilibrium (disordered) state to unity in the nonequilibrium (ordered) state.
6
Amari, Shun-ichi, e Noboru Murata. "Statistical Theory of Learning Curves under Entropic Loss Criterion". Neural Computation 5, n. 1 (gennaio 1993): 140–53. http://dx.doi.org/10.1162/neco.1993.5.1.140.
Abstract (sommario):
The present paper elucidates a universal property of learning curves, which shows how the generalization error, training error, and the complexity of the underlying stochastic machine are related and how the behavior of a stochastic machine is improved as the number of training examples increases. The error is measured by the entropic loss. It is proved that the generalization error converges to H0, the entropy of the conditional distribution of the true machine, as H0 + m*/(2t), while the training error converges as H0 - m*/(2t), where t is the number of examples and m* shows the complexity of the network. When the model is faithful, implying that the true machine is in the model, m* is reduced to m, the number of modifiable parameters. This is a universal law because it holds for any regular machine irrespective of its structure under the maximum likelihood estimator. Similar relations are obtained for the Bayes and Gibbs learning algorithms. These learning curves show the relation among the accuracy of learning, the complexity of a model, and the number of training examples.
7
Rekik, Sawsan, e Noureddine Ellouze. "QRS detection combining entropic criterion and wavelet transform". International Journal of Signal and Imaging Systems Engineering 9, n. 4/5 (2016): 299. http://dx.doi.org/10.1504/ijsise.2016.078264.
8
Mercurio, Peter Joseph, Yuehua Wu e Hong Xie. "Option Portfolio Selection with Generalized Entropic Portfolio Optimization". Entropy 22, n. 8 (22 luglio 2020): 805. http://dx.doi.org/10.3390/e22080805.
Abstract (sommario):
In this third and final paper of our series on the topic of portfolio optimization, we introduce a further generalized portfolio selection method called generalized entropic portfolio optimization (GEPO). GEPO extends discrete entropic portfolio optimization (DEPO) to include intervals of continuous returns, with direct application to a wide range of option strategies. This lays the groundwork for an adaptable optimization framework that can accommodate a wealth of option portfolios, including popular strategies such as covered calls, married puts, credit spreads, straddles, strangles, butterfly spreads, and even iron condors. These option strategies exhibit mixed returns: a combination of discrete and continuous returns with performance best measured by portfolio growth rate, making entropic portfolio optimization an ideal method for option portfolio selection. GEPO provides the mathematical tools to select efficient option portfolios based on their growth rate and relative entropy. We provide an example of GEPO applied to real market option portfolio selection and demonstrate how GEPO outperforms traditional Kelly criterion strategies.
9
Krstić, Vladimir R., e Miroslav L. Dukić. "Decision Feedback Blind Equalizer with Tap-Leaky Whitening for Stable Structure-Criterion Switching". International Journal of Digital Multimedia Broadcasting 2014 (2014): 1–10. http://dx.doi.org/10.1155/2014/987039.
Abstract (sommario):
The research presented in this paper improves the structure-criterion switching performance of the blind decision feedback equalizer (DFE) which eliminates error propagation effects by optimizing both the structure and the cost criterion. To conquer the complexity of the 64-QAM (quadrature amplitude modulated) signal constellation, the stochastic entropy-gradient algorithm is additionally regularized by the coefficient leaky term to avoid a coefficients norm overgrowth of the received signal whitener. Effectively, the leak of coefficients is employed to ensure a stable structure-criterion switching of DFE between blind and decision-directed operation modes. The optimization of the resulting whitening algorithm is achieved by means of two free, leaky and entropic, parameters which act in opposition to each other. Both, the influence of the 64-QAM signal on the feedback filter behavior and the parametric optimization of the whitening algorithm are analyzed through simulations.
10
Rekik, Sawsan, e Noureddinne Ellouze. "P-Wave Detection Combining Entropic Criterion and Wavelet Transform". Journal of Signal and Information Processing 06, n. 03 (2015): 217–26. http://dx.doi.org/10.4236/jsip.2015.63020.
11
Inoue, Kei. "An Improved Calculation Formula of the Extended Entropic Chaos Degree and Its Application to Two-Dimensional Chaotic Maps". Entropy 23, n. 11 (14 novembre 2021): 1511. http://dx.doi.org/10.3390/e23111511.
Abstract (sommario):
The Lyapunov exponent is primarily used to quantify the chaos of a dynamical system. However, it is difficult to compute the Lyapunov exponent of dynamical systems from a time series. The entropic chaos degree is a criterion for quantifying chaos in dynamical systems through information dynamics, which is directly computable for any time series. However, it requires higher values than the Lyapunov exponent for any chaotic map. Therefore, the improved entropic chaos degree for a one-dimensional chaotic map under typical chaotic conditions was introduced to reduce the difference between the Lyapunov exponent and the entropic chaos degree. Moreover, the improved entropic chaos degree was extended for a multidimensional chaotic map. Recently, the author has shown that the extended entropic chaos degree takes the same value as the total sum of the Lyapunov exponents under typical chaotic conditions. However, the author has assumed a value of infinity for some numbers, especially the number of mapping points. Nevertheless, in actual numerical computations, these numbers are treated as finite. This study proposes an improved calculation formula of the extended entropic chaos degree to obtain appropriate numerical computation results for two-dimensional chaotic maps.
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Zhu, Zhongfan, Yongpeng Zhang, Lufeng Gou e Bo Pang. "An Entropic Approach to Estimating the Instability Criterion of People in Floodwaters". Entropy 23, n. 1 (6 gennaio 2021): 74. http://dx.doi.org/10.3390/e23010074.
Abstract (sommario):
People are always susceptible to a loss of stability in urban floodwaters that leads to serious casualties. Thus, the safety criterion for the instability of people in floodwaters must be determined. In this study, the hydrodynamic criterion of the instability of people in floodwaters in terms of the incipient velocity and water depth is derived using the probability method based on Shannon entropy theory. The derived model can characterize variations in the incipient velocity of people in floodwaters with respect to the inundating water depth. Furthermore, a comparison with seven experimental datasets available in the literature shows the validity of the proposed entropy-based model considering data scattering. A sensitivity analysis of the derived model to some of the incorporated parameters was performed, and the qualitative results are in accordance with our understanding of the physical mechanism of the instability of people in floodwaters. Taking the physical parameters (height and mass) of Chinese adults and children as a representative example, this study also showed the vulnerability degree of Chinese adults and children subject to floodwaters. These findings could provide a reference for administrators and stakeholders for flood hazard mitigation and flood strategy management. This study shows that an entropy-based method could be a valuable addition to existing deterministic models for characterizing the instability criterion of people in an urban flooding event.
13
Popov, Valentin. "Energetic criterion for adhesion in viscoelastic contacts with non-entropic surface interaction". Reports in Mechanical Engineering 2, n. 1 (23 marzo 2021): 57–64. http://dx.doi.org/10.31181/rme200102057p.
Abstract (sommario):
We suggest a detachment criterion for a viscoelastic elastomer contact based on Griffith's idea about the energy balance at an infinitesimal advancement of the boundary of an adhesive crack. At the moment of detachment of a surface element at the boundary of an adhesive contact, there is some quick (instant) relaxation of stored elastic energy which can be expressed in terms of the creep function of the material. We argue that it is only this "instant part" of stored energy which is available for doing work of adhesion and thus it is only this part of energy relaxation that must be used in Griffith's energy balance. The described idea has several restrictions. Firstly, in this pure form, it is only valid for adhesive forces having an infinitely small range of action (which we call the JKR-limit). Secondly, it is only applicable to non-entropic (energetic) interfaces, which detach "at once" and do not possess their own kinetics of detachment.
14
Abreu, Everton M. C., Jorge Ananias Neto, Edésio M. Barboza e Rafael C. Nunes. "Tsallis and Kaniadakis statistics from the viewpoint of entropic gravity formalism". International Journal of Modern Physics A 32, n. 05 (19 febbraio 2017): 1750028. http://dx.doi.org/10.1142/s0217751x17500282.
Abstract (sommario):
It has been shown in the literature that effective gravitational constants, which are derived from Verlinde’s formalism, can be used to introduce the Tsallis and Kaniadakis statistics. This method provides a simple alternative to the usual procedure normally used in these non-Gaussian statistics. We have applied our formalism in both Jeans mass criterion of stability and the free fall time collapsing of a self-gravitating system where new results were obtained. A possible connection between our formalism and deviations of Newton’s law of gravitation in a submillimeter range was carried out.
15
Burda, E. A., D. E. Bogomolov e A. P. Naumenko. "ENTROPY APPROACH FOR FILTERING ACOUSTIC EMISSION SIGNALS". Kontrol'. Diagnostika, n. 295 (gennaio 2023): 34–44. http://dx.doi.org/10.14489/td.2023.01.pp.034-044.
Abstract (sommario):
The acoustic emission (AE) method has been successfully used in recent years to monitor the condition of industrial and civil infrastructure structures. In AE, time-of-arrival (ToA) estimation is considered a key parameter for the accurate location of a growing defect. This paper describes an entropy-based filtering approach to improve the ToA estimation of a signal in a noisy environment compared to the commonly used Akaike Information Criterion (AIC). The proposed method consists of coarsening the input data using the Crutchfield-Packard algorithm and calculating the local (instantaneous) entropy. In the present study, it is demonstrated that the local entropy of the noise component of the signal the local entropy of the useful (informative) part can be distinguished. As a result, the approach allows filtering out the noise component by selecting appropriate filtering parameters. The proposed approach has been tested on experimental data obtained on an aluminium plate used to pinpoint an AE source. The entropic approach demonstrates higher accuracy in final target location of AE sources at significant noise levels compared to classical AIC.
16
Gou, Lufeng, Yun Liu, Yongpeng Zhang, Zhongfan Zhu, Dingzhi Peng e Jie Dou. "Estimating the instability criterion of vehicles in urban flooding by an entropic method". Urban Climate 41 (gennaio 2022): 101069. http://dx.doi.org/10.1016/j.uclim.2021.101069.
17
Karginova-Gubinova, V. V. "Assessment of Homogeneity and Convergence of Environmental Performance of Enterprises into One Holding". Finance: Theory and Practice 27, n. 5 (23 ottobre 2023): 170–81. http://dx.doi.org/10.26794/2587-5671-2023-27-5-170-181.
Abstract (sommario):
Taking into account the need for transition to sustainable development of the economy, it seems relevant to consider whether the holding is an effective structure to minimize the negative impact on the environment: is there a convergence of the environmental performance of the holding’s enterprises with a general increase in its responsibility?The purpose of the research is to assess the degree of homogeneity and convergence of the environmental performance of Russian enterprises within the same holding, as well as to determine the relationship between the current level of homogeneity of the holding and the rate of its convergence and overall environmental responsibility. The environmental performance of 11 Russian holdings and 105 constituent enterprises for 2017–2021 was examined.The methodology involved the calculation of entropy and descriptive statistics; the evaluation of the homogeneity of holdings and its convergence, phase transition periods, and the relationship between homogeneity and other characteristics using analysis of variance and regression.The results of the study showed that Russian holdings correspond to the ascending line of the entropic criterion of social development, but at present the phase transition from a heterogeneous to a homogeneous state is incomplete, and homogeneous holdings are unstable. The influence of the type of corporate environmental policy on the homogeneity of the holding, the degree of its convergence and environmental responsibility was revealed.The scientific novelty of the work lies in the consideration of homogeneity and convergence of environmental characteristics of systematically unstudied objects — t he enterprises of one holding; the inappropriateness of the perception of holdings as homogeneous objects is confirmed. Theoretical significance has shown the possibility of using the entropic criterion of the theory of social development and dialectical logic to study the homogeneity and convergence of the indicators of holdings, as well as the developed methodology of their assessment.Recommendations for the authorities and managers of companies, the implementation of which will increase the sustainability of the economy, are of practical value.
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Mercurio, Peter Joseph, Yuehua Wu e Hong Xie. "Portfolio Optimization for Binary Options Based on Relative Entropy". Entropy 22, n. 7 (9 luglio 2020): 752. http://dx.doi.org/10.3390/e22070752.
Abstract (sommario):
The portfolio optimization problem generally refers to creating an investment portfolio or asset allocation that achieves an optimal balance of expected risk and return. These portfolio returns are traditionally assumed to be continuous random variables. In An Entropy-Based Approach to Portfolio Optimization, we introduced a novel non-parametric optimization method based on Shannon entropy, called return-entropy portfolio optimization (REPO), which offers a simple and fast optimization algorithm for assets with continuous returns. Here, in this paper, we would like to extend the REPO approach to the optimization problem for assets with discrete distributed returns, such as those from a Bernoulli distribution like binary options. Under a discrete probability distribution, portfolios of binary options can be viewed as repeated short-term investments with an optimal buy/sell strategy or general betting strategy. Upon the outcome of each contract, the portfolio incurs a profit (success) or loss (failure). This is similar to a series of gambling wagers. Portfolio selection under this setting can be formulated as a new optimization problem called discrete entropic portfolio optimization (DEPO). DEPO creates optimal portfolios for discrete return assets based on expected growth rate and relative entropy. We show how a portfolio of binary options provides an ideal general setting for this kind of portfolio selection. As an example we apply DEPO to a portfolio of short-term foreign exchange currency pair binary options from the NADEX exchange platform and show how it outperforms leading Kelly criterion strategies. We also provide an additional example of a gambling application using a portfolio of sports bets over the course of an NFL season and present the advantages of DEPO over competing Kelly criterion strategies.
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Hochberg, David, e Josep Ribó. "Entropic Analysis of Mirror Symmetry Breaking in Chiral Hypercycles". Life 9, n. 1 (15 marzo 2019): 28. http://dx.doi.org/10.3390/life9010028.
Abstract (sommario):
Replicators are fundamental to the origin of life and evolvability. Biology exhibits homochirality: only one of two enantiomers is used in proteins and nucleic acids. Thermodynamic studies of chemical replicators able to lead to homochirality shed valuable light on the origin of homochirality and life in conformity with the underlying mechanisms and constraints. In line with this framework, enantioselective hypercyclic replicators may lead to spontaneous mirror symmetry breaking (SMSB) without the need for additional heterochiral inhibition reactions, which can be an obstacle for the emergence of evolutionary selection properties. We analyze the entropy production of a two-replicator system subject to homochiral cross-catalysis which can undergo SMSB in an open-flow reactor. The entropy exchange with the environment is provided by the input and output matter flows, and is essential for balancing the entropy production at the non-equilibrium stationary states. The partial entropy contributions, associated with the individual elementary flux modes, as defined by stoichiometric network analysis (SNA), describe how the system’s internal currents evolve, maintaining the balance between entropy production and exchange, while minimizing the entropy production after the symmetry breaking transition. We validate the General Evolution Criterion, stating that the change in the chemical affinities proceeds in a way as to lower the value of the entropy production.
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Gonzalez-Aguirre, Eneko, Jon Gastelurrutia, Mahesh Suresh Patil e Luis del Portillo-Valdes. "Avoiding Thermal Issues During Fast Charging Starting with Proper Cell Selection Criteria". Journal of The Electrochemical Society 168, n. 11 (1 novembre 2021): 110523. http://dx.doi.org/10.1149/1945-7111/ac3348.
Abstract (sommario):
Proper cell selection is determinant to optimize systems and reduce risks for new and high demanding areas such as electromobility. Thermal performance must be an indispensable selection criterion to avoid thermal issues in these fields, so cells should be correctly characterised and modelled. In this paper, an improved cell selection methodology that focuses on the thermal performance criterion especially for fast charging applications is proposed. After a first selection, two cell candidates were characterised and their heat generation was modelled and compared. With the selected cell, heat generation rate was determined and a 3C fast charge was performed to evidence the predicted thermal performance. The improved methodology identified a cell with an advantageous entropic heat coefficient (EHC) for fast charging, decreasing the heat energy generation by 54% concerning the other candidate cell, which results in optimisation of the thermal management system (TMS). This emphasizes the importance of proper cell selection based on thorough thermal characterization.
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Issartel, J. P. "Emergence of a linear tracer source from air concentration measurements". Atmospheric Chemistry and Physics Discussions 4, n. 3 (12 maggio 2004): 2615–70. http://dx.doi.org/10.5194/acpd-4-2615-2004.
Abstract (sommario):
Abstract. The measurement of atmospheric concentrations by a monitoring network is potentially a useful tool investigated for the identification of the widespread sources of trace species. The paper addresses inversion strategies using base functions multiplicatively deduced from the concentrations adjoint to the measurements. This follows the concept of illumination: the various regions are well, poorly or not seen at all. With ordinary adjoint functions the illumination becomes excessive close to the detectors. This may be corrected by attributing each point of the space time domain a geometric weight. After stating the statistical implications, the choice of this renormalising function is shown to be constrained by an unambiguous formal criterion. The expectable values of the measurements are distinguished from the measurement errors. The entropic nature of the criterion is explained; it amounts to evenly distribute the information between the points organised with their weights as a "known domain" describing the influence of the measurements. Finally the criterion is shown to coincide with the definition of the pure states of quantum statistics, and this interpretation is investigated to describe the influence of the measurement uncertainties on the quality of a source estimate. The theory is illustrated by calculations performed with the experimental source ETEX1.
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Meisenheimer, P. B., e J. T. Heron. "Oxides and the high entropy regime: A new mix for engineering physical properties". MRS Advances 5, n. 64 (2020): 3419–36. http://dx.doi.org/10.1557/adv.2020.295.
Abstract (sommario):
AbstractHistorically, the enthalpy is the criterion for oxide materials discovery and design. In this regime, highly controlled thin film epitaxy can be leveraged to manifest bulk and interfacial phases that are non-existent in bulk equilibrium phase diagrams. With the recent discovery of entropy-stabilized oxides, entropy and disorder engineering has been realized as an orthogonal approach. This has led to the nucleation and rapid growth of research on high-entropy oxides – multicomponent oxides where the configurational entropy is large but its contribution to its stabilization need not be significant or is currently unknown. From current research, it is clear that entropy enhances the chemical solubility of species and can realize new stereochemical configurations which has led to the rapid discovery of new phases and compositions. The research has expanded beyond studies to understand the role of entropy in stabilization and realization of new crystal structures to now include physical properties and the roles of local and global disorder. Here, key observations made regarding the dielectric and magnetic properties are reviewed. These materials have recently been observed to display concerted symmetry breaking, metal-insulator transitions, and magnetism, paving the way for engineering of these and potentially other functional phenomena. Excitingly, the disorder in these oxides allows for new interplay between spin, orbital, charge, and lattice degrees of freedom to design the physical behavior. We also provide a perspective on the state of the field and prospects for entropic oxide materials in applications considering their unique characteristics.
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Caglioti, V. "An entropic criterion for minimum uncertainty sensing in recognition and localization. I. Theoretical and conceptual aspects". IEEE Transactions on Systems, Man and Cybernetics, Part B (Cybernetics) 31, n. 2 (aprile 2001): 187–96. http://dx.doi.org/10.1109/3477.915342.
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Urniezius, Renaldas, Benas Kemesis e Rimvydas Simutis. "Bridging Offline Functional Model Carrying Aging-Specific Growth Rate Information and Recombinant Protein Expression: Entropic Extension of Akaike Information Criterion". Entropy 23, n. 8 (16 agosto 2021): 1057. http://dx.doi.org/10.3390/e23081057.
Abstract (sommario):
This study presents a mathematical model of recombinant protein expression, including its development, selection, and fitting results based on seventy fed-batch cultivation experiments from two independent biopharmaceutical sites. To resolve the overfitting feature of the Akaike information criterion, we proposed an entropic extension, which behaves asymptotically like the classical criteria. Estimation of recombinant protein concentration was performed with pseudo-global optimization processes while processing offline recombinant protein concentration samples. We show that functional models including the average age of the cells and the specific growth at induction or the start of product biosynthesis are the best descriptors for datasets. We also proposed introducing a tuning coefficient that would force the modified Akaike information criterion to avoid overfitting when the designer requires fewer model parameters. We expect that a lower number of coefficients would allow the efficient maximization of target microbial products in the upstream section of contract development and manufacturing organization services in the future. Experimental model fitting was accomplished simultaneously for 46 experiments at the first site and 24 fed-batch experiments at the second site. Both locations contained 196 and 131 protein samples, thus giving a total of 327 target product concentration samples derived from the bioreactor medium.
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WEI, HSIEN-HUNG, e JENG-SHIUNG JAN. "Self-propulsion and dispersion of reactive colloids due to entropic anisotropy". Journal of Fluid Mechanics 657 (17 giugno 2010): 64–88. http://dx.doi.org/10.1017/s0022112010001369.
Abstract (sommario):
In this paper, self-motion of reactive colloids and their dispersion behaviour are theoretically examined. The motion is driven by an osmotic force imbalance arising from non-uniform atmospheres of reactive solutes around the colloids. The propulsion here is not limited to Janus-like particles. It can also occur to particles having ‘uniform’ reactivity due to the more universal mechanism – entropic anisotropy created by breaking in rotational symmetry. The idea is demonstrated by examining the motion of a reactive particle due to asymmetry in its shape or to the presence of an additional particle. In the two-particle problem, in particular, we find that sink (source) particles can self-migrate towards (apart from) each other at velocities varying as R−2, resembling Coulomb attraction (repulsion), where R is the inter-particle distance. Because of this Coulomb-like nature, a suspension of sink particles could undergo collective flocculation due to unscreened osmotic attraction. The criterion for an occurrence of the flocculation is also established. It reveals that the flocculation can occur if the particle volume fraction is within a certain window in terms of the solute concentration and the particle reactivity. The stability of reactive suspensions is also discussed using the modified Derjaguin–Landau–Verwey–Overbeek (DLVO) theory that takes account of the competition between long-range reaction-induced osmotic forces and short-range colloidal forces. A more generalized view for the present self-driven particle motion is elucidated by a simple scaling theory, providing lucid accounts for the self-motion of two particles, composite bodies, and Janus particles – all are driven by dipolar distortions in potential energy. Comparison with phoretic self-swimmers is also discussed.
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Rocha, Luiz Célio S., Mariana S. Rocha, Paulo Rotella Junior, Giancarlo Aquila, Rogério S. Peruchi, Karel Janda e Rômulo O. Azevêdo. "Robust Multi-Objective Optimization for Response Surface Models Applied to Direct Low-Value Natural Gas Conversion Processes". Entropy 23, n. 2 (21 febbraio 2021): 248. http://dx.doi.org/10.3390/e23020248.
Abstract (sommario):
The high proportion of CO2/CH4 in low aggregated value natural gas compositions can be used strategically and intelligently to produce more hydrocarbons through oxidative methane coupling (OCM). The main goal of this study was to optimize direct low-value natural gas conversion via CO2-OCM on metal oxide catalysts using robust multi-objective optimization based on an entropic measure to choose the most preferred Pareto optimal point as the problem’s final solution. The responses of CH4 conversion, C2 selectivity, and C2 yield are modeled using the response surface methodology. In this methodology, decision variables, e.g., the CO2/CH4 ratio, reactor temperature, wt.% CaO and wt.% MnO in ceria catalyst, are all employed. The Pareto optimal solution was obtained via the following combination of process parameters: CO2/CH4 ratio = 2.50, reactor temperature = 1179.5 K, wt.% CaO in ceria catalyst = 17.2%, wt.% MnO in ceria catalyst = 6.0%. By using the optimal weighting strategy w1 = 0.2602, w2 = 0.3203, w3 = 0.4295, the simultaneous optimal values for the objective functions were: CH4 conversion = 8.806%, C2 selectivity = 51.468%, C2 yield = 3.275%. Finally, an entropic measure used as a decision-making criterion was found to be useful in mapping the regions of minimal variation among the Pareto optimal responses and the results obtained, and this demonstrates that the optimization weights exert influence on the forecast variation of the obtained response.
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Balunov, Alexander I. "COMPOSITIONS CALCULATION OF COMPLEX DISTILLATION SYSTEM PRODUCT FLOWS BASED ON THE EXTENDED VERSION OF THE MAXIMUM ENTROPY PRINCIPLE". IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 63, n. 1 (10 dicembre 2019): 99–104. http://dx.doi.org/10.6060/ivkkt.20206301.6072.
Abstract (sommario):
A method for calculating the most likely product compositions of athermal mixture separation in complex distillation systems, including systems of simple recycling and non-recycling columns, complex columns with side sampling, systems with joint heat flows, and others. The method is based on an extended version of the maximum entropy principle. The informational entropy of complex experiment involving conditional entropy and conditional probabilities is used as the likelihood criterion. The adopted axiomatic allows one to obtain the most probable component distributions in the product flows of the system, which corresponds to the complex experience maximum entropy in accordance with the balance restrictions. It has been demonstrated that athermal properties accounting of the mixture create dependencies that include entropic activity coefficients associated with the conditional entropy in a typical thermodynamics form. Dependencies are a special case of the correlations obtained for ideal mixtures. The method for calculating the entropy activity coefficients as functions of the components molecule relative volumes and the mixture molar composition has been provided. This method is focused on the design version of the distillation system calculation. It allows to determine the parameters characterizing the process length (the number of theoretical separation steps in the non-selective mode) and the product flow composition products under the product quality restrictions. The accounting of mixture athermal nature leads to an increased duration of the process and has a slight impact on the product compositions. A comparison is given of the results of the calculation of the composition of the product flows of a typical gas fractionating unit with and without taking into account the athermal properties of the mixture to be separated with the data of an industrial experiment.
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Caglioti, V. "An entropic criterion for minimum uncertainty sensing in recognition and localization. II. A case study on directional distance measurements". IEEE Transactions on Systems, Man and Cybernetics, Part B (Cybernetics) 31, n. 2 (aprile 2001): 197–214. http://dx.doi.org/10.1109/3477.915343.
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Li, Tongxin, Yue Chen, Bo Sun, Adam Wierman e Steven Low. "Information Aggregation for Constrained Online Control". ACM SIGMETRICS Performance Evaluation Review 49, n. 1 (22 giugno 2022): 7–8. http://dx.doi.org/10.1145/3543516.3461737.
Abstract (sommario):
We consider a two-controller online control problem where a central controller chooses an action from a feasible set that is determined by time-varying and coupling constraints, which depend on all past actions and states. The central controller's goal is to minimize the cumulative cost; however, the controller has access to neither the feasible set nor the dynamics directly, which are determined by a remote local controller. Instead, the central controller receives only an aggregate summary of the feasibility information from the local controller, which does not know the system costs. We show that it is possible for an online algorithm using feasibility information to nearly match the dynamic regret of an online algorithm using perfect information whenever the feasible sets satisfy a causal invariance criterion and there is a sufficiently large prediction window size. To do so, we use a form of feasibility aggregation based on entropic maximization in combination with a novel online algorithm, named Penalized Predictive Control (PPC).
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Lomba, E., J. L. López-Martín, H. M. Cataldo e C. F. Tejero. "Phase transitions in simple fluids: An application of a one-phase entropic criterion to Lennard-Jones and point Yukawa fluids". Physical Review E 49, n. 6 (1 giugno 1994): 5164–68. http://dx.doi.org/10.1103/physreve.49.5164.
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Costa, Ana, Roope Uola e Otfried Gühne. "Entropic Steering Criteria: Applications to Bipartite and Tripartite Systems". Entropy 20, n. 10 (5 ottobre 2018): 763. http://dx.doi.org/10.3390/e20100763.
Abstract (sommario):
The effect of quantum steering describes a possible action at a distance via local measurements. Whereas many attempts on characterizing steerability have been pursued, answering the question as to whether a given state is steerable or not remains a difficult task. Here, we investigate the applicability of a recently proposed method for building steering criteria from generalized entropic uncertainty relations. This method works for any entropy which satisfy the properties of (i) (pseudo-) additivity for independent distributions; (ii) state independent entropic uncertainty relation (EUR); and (iii) joint convexity of a corresponding relative entropy. Our study extends the former analysis to Tsallis and Rényi entropies on bipartite and tripartite systems. As examples, we investigate the steerability of the three-qubit GHZ and W states.
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González-Serrano, Lydia, Pilar Talón-Ballestero, Sergio Muñoz-Romero, Cristina Soguero-Ruiz e José Luis Rojo-Álvarez. "Entropic Statistical Description of Big Data Quality in Hotel Customer Relationship Management". Entropy 21, n. 4 (19 aprile 2019): 419. http://dx.doi.org/10.3390/e21040419.
Abstract (sommario):
Customer Relationship Management (CRM) is a fundamental tool in the hospitality industry nowadays, which can be seen as a big-data scenario due to the large amount of recordings which are annually handled by managers. Data quality is crucial for the success of these systems, and one of the main issues to be solved by businesses in general and by hospitality businesses in particular in this setting is the identification of duplicated customers, which has not received much attention in recent literature, probably and partly because it is not an easy-to-state problem in statistical terms. In the present work, we address the problem statement of duplicated customer identification as a large-scale data analysis, and we propose and benchmark a general-purpose solution for it. Our system consists of four basic elements: (a) A generic feature representation for the customer fields in a simple table-shape database; (b) An efficient distance for comparison among feature values, in terms of the Wagner-Fischer algorithm to calculate the Levenshtein distance; (c) A big-data implementation using basic map-reduce techniques to readily support the comparison of strategies; (d) An X-from-M criterion to identify those possible neighbors to a duplicated-customer candidate. We analyze the mass density function of the distances in the CRM text-based fields and characterized their behavior and consistency in terms of the entropy and of the mutual information for these fields. Our experiments in a large CRM from a multinational hospitality chain show that the distance distributions are statistically consistent for each feature, and that neighbourhood thresholds are automatically adjusted by the system at a first step and they can be subsequently more-finely tuned according to the manager experience. The entropy distributions for the different variables, as well as the mutual information between pairs, are characterized by multimodal profiles, where a wide gap between close and far fields is often present. This motivates the proposal of the so-called X-from-M strategy, which is shown to be computationally affordable, and can provide the expert with a reduced number of duplicated candidates to supervise, with low X values being enough to warrant the sensitivity required at the automatic detection stage. The proposed system again encourages and supports the benefits of big-data technologies in CRM scenarios for hotel chains, and rather than the use of ad-hoc heuristic rules, it promotes the research and development of theoretically principled approaches.
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Anikin, A. V., N. I. Yashina, O. I. Kashina, N. N. Pronchatova-Rubtsova e M. E. Shashkina. "MONITORING THE VOLATITY OF CAPITAL CIRCULATED IN THE POPULATION DEPOSITS MARKET AND ATTRACTED BY CREDIT ORGANIZATIONS BASED ON THE ENTROPIC CRITERION". Вестник Алтайской академии экономики и права 2, n. 11 2020 (2020): 163–69. http://dx.doi.org/10.17513/vaael.1407.
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Salim, Jana, e Hamparsum Bozdogan. "A Novel Approach to Forecasting High Dimensional S&P500 Portfolio Using VARX Model with Information Complexity". Journal of Economics and Technology Research 3, n. 2 (17 maggio 2022): p1. http://dx.doi.org/10.22158/jetr.v3n2p1.
Abstract (sommario):
This study considers vector autoregressive models that allow for endogenous and exogeneous regressors VARX using multivariate OLS regression. For the model selection, we follow bozdogan’s entropic or information-theoretic measure of complexity ICOMP criterion of the estimated inverse Fisher information matrix IFIM in choosing the best VARX lag parameter and we established that ICOMP outperform the conventional information criteria. As an empirical illustration, we reduced the dimension of the S&P500 multivariate time series using Sparse Principal Component Analysis (SPCA) and chose the best subset of 37 stocks belonging to six sectors. We then performed a portfolio of stocks based on the highest SPC loading weight matrix, plus the S&P500 index. Furthermore, we applied the proposed VARX model to predict the price movements in the constructed portfolio, where the S&P500 index was treated as an exogeneous regressor of the VARX model. It has been deduced too that the buy-sell decision making in response to VARX (4,0) for a stock outperforms investing and holding the stock over the out-of-sample period.
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Li, Tongxin, Yue Chen, Bo Sun, Adam Wierman e Steven H. Low. "Information Aggregation for Constrained Online Control". Proceedings of the ACM on Measurement and Analysis of Computing Systems 5, n. 2 (giugno 2021): 1–35. http://dx.doi.org/10.1145/3460085.
Abstract (sommario):
This paper considers an online control problem involving two controllers. A central controller chooses an action from a feasible set that is determined by time-varying and coupling constraints, which depend on all past actions and states. The central controller's goal is to minimize the cumulative cost; however, the controller has access to neither the feasible set nor the dynamics directly, which are determined by a remote local controller. Instead, the central controller receives only an aggregate summary of the feasibility information from the local controller, which does not know the system costs. We show that it is possible for an online algorithm using feasibility information to nearly match the dynamic regret of an online algorithm using perfect information whenever the feasible sets satisfy a causal invariance criterion and there is a sufficiently large prediction window size. To do so, we use a form of feasibility aggregation based on entropic maximization in combination with a novel online algorithm, named Penalized Predictive Control (PPC) and demonstrate that aggregated information can be efficiently learned using reinforcement learning algorithms. The effectiveness of our approach for closed-loop coordination between central and local controllers is validated via an electric vehicle charging application in power systems.
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Hauptfleischová, Barbora, Lukáš Novotný, Jiří Falta, Martin Machálka e Matěj Sulitka. "In-Process Chatter Detection in Milling: Comparison of the Robustness of Selected Entropy Methods". Journal of Manufacturing and Materials Processing 6, n. 5 (21 ottobre 2022): 125. http://dx.doi.org/10.3390/jmmp6050125.
Abstract (sommario):
This article deals with the issue of online chatter detection during milling. The aim is to achieve a verification of the reliability and robustness of selected methods for the detection of chatter that can be evaluated on the machine tool in real time by using the accelerometer signal. In the introductory part of the paper, an overview of the current state of the art in the field of chatter detection is summarized. Entropic methods have been selected that evaluate the presence of chatter from the qualitative behavior of the signal rather than from the magnitude of its amplitude, because the latter can be affected by the transmission of vibrations to the accelerometer position. Another criterion for selection was the potential for practical implementation in a real-time evaluation of the accelerometer signal, which is nowadays quite commonly installed on machine tools. The robustness of the methods was tested with respect to tool compliance, which affects both chatter occurrence and vibration transfer to the accelerometer location. Therefore, the study was carried out on a slender milling tool with two different overhangs and on a rigid roughing tool. The reference stability assessment for each measurement was based on samples of the machined surface. The signals obtained from the accelerometer were then post-processed and used to calculate the chatter indicators. In this way, it was possible to compare different methods in terms of their ability to achieve reliable in-process detection of chatter and in terms of the computational complexity of the indicator.
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Soulayman, S. Sh. "Theoretical Melting Curves of Alkali Halides". Zeitschrift für Naturforschung A 47, n. 6 (1 giugno 1992): 753–60. http://dx.doi.org/10.1515/zna-1992-0606.
Abstract (sommario):
AbstractAn analysis of the melting curves of alkali halides is given. The study is based on the Improved Unsymmetrized Self-Consistent Field Method (IUSCFM) for strongly anharmonic crystals with complex lattice and the energy, entropy and Ross’s criterions in calculating the melting curves of alkali halides. The anharmonicities up to sixth order have been taken into consideration. The energy criterion was proven to be the most correct one along the melting curves of the high pressure modification (CsCl structure) while the entropy and Ross's criterions lead to a little better agreement with experiment than the energy criterion when dealing with rocksalt structure. Calculations of the melting curves of KCl and CsCl are compared with the experimental results.
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BATLE, J., M. CASAS, A. R. PLASTINO e A. PLASTINO. "QUANTUM ENTROPIES AND ENTANGLEMENT". International Journal of Quantum Information 03, n. 01 (marzo 2005): 99–104. http://dx.doi.org/10.1142/s021974990500058x.
Abstract (sommario):
The nature of quantum entropies, and its use in Quantum Information Theory in the form of (i) total entropy, (ii) relative entropy and (iii) conditional entropy is revisited. In this ordering, we first show the correlations existing between the total q-entropy and entanglement, quantified in the form of entanglement of formation. Then, we revisit the use of the quantum relative entropy as a measure of entanglement, and we finally discuss some features of the quantum conditional q-entropies, which are used in turn as a separability criterion.
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Barbosa, Wagner A., Sérgio Luiz E. F. da Silva, Erick de la Barra e João M. de Araújo. "Full-waveform inversion based on generalized Rényi entropy using patched Green’s function techniques". PLOS ONE 17, n. 11 (11 novembre 2022): e0275416. http://dx.doi.org/10.1371/journal.pone.0275416.
Abstract (sommario):
The estimation of physical parameters from data analyses is a crucial process for the description and modeling of many complex systems. Based on Rényi α-Gaussian distribution and patched Green’s function (PGF) techniques, we propose a robust framework for data inversion using a wave-equation based methodology named full-waveform inversion (FWI). From the assumption that the residual seismic data (the difference between the modeled and observed data) obeys the Rényi α-Gaussian probability distribution, we introduce an outlier-resistant criterion to deal with erratic measures in the FWI context, in which the classical FWI based on l2-norm is a particular case. The new misfit function arises from the probabilistic maximum-likelihood method associated with the α-Gaussian distribution. The PGF technique works on the forward modeling process by dividing the computational domain into outside target area and target area, where the wave equation is solved only once on the outside target (before FWI). During the FWI processing, Green’s functions related only to the target area are computed instead of the entire computational domain, saving computational efforts. We show the effectiveness of our proposed approach by considering two distinct realistic P-wave velocity models, in which the first one is inspired in the Kwanza Basin in Angola and the second in a region of great economic interest in the Brazilian pre-salt field. We call our proposal by the abbreviation α-PGF-FWI. The results reveal that the α-PGF-FWI is robust against additive Gaussian noise and non-Gaussian noise with outliers in the limit α → 2/3, being α the Rényi entropic index.
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Poh, Leslie, Qi Wu, Zhengbin Pan, Manfred H. Wagner e Esmaeil Narimissa. "Fracture in elongational flow of two low-density polyethylene melts". Rheologica Acta 62, n. 5-6 (giugno 2023): 317–31. http://dx.doi.org/10.1007/s00397-023-01392-1.
Abstract (sommario):
AbstractSamples of two commercial low-density polyethylene melts were investigated with respect to their fracture behavior in controlled uniaxial extensional flow at constant strain rate in a filament stretching rheometer. In order to assess the possible influence of grain boundaries on fracture, the samples were prepared by three different types of pre-treatment: by compression molding of (1) virgin pellets used as received, (2) pellets homogenized in a twin-screw extruder, and (3) pellets that were milled into powder by cryogenic grinding under liquid nitrogen. The elongational stress growth data were analyzed by the Extended Hierarchical Multi-mode Molecular Stress Function (EHMMSF) model developed by Wagner et al. (Rheol. Acta 61, 281-298 (2022)) for long-chain branched (LCB) polymer melts. The EHMMSF model quantifies the elongational stress growth including the maximum in the elongational viscosity of LDPE melts based solely on the linear-viscoelastic relaxation spectrum and two nonlinear material parameters, the dilution modulus GD and a characteristic stretch parameter $${\overline{\lambda}}_m$$ λ ¯ m . Within experimental accuracy, model predictions are in excellent agreement with the elongational stress growth data of the two LDPE melts, independent of the preparation method used. At sufficiently high strain rates, the fracture of the polymer filaments was observed and is in general accordance with the entropic fracture criterion implemented in the EHMMSF model. High-speed videography reveals that fracture is preceded by parabolic crack opening, which is characteristic for elastic fracture and which has been observed earlier in filament stretching of monodisperse polystyrene solutions. Here, for the first time, we demonstrate the appearance of a parabolic crack opening in the fracture process of polydisperse long-chain branched polyethylene melts.
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Issartel, J. P. "Emergence of a tracer source from air concentration measurements, a new strategy for linear assimilation". Atmospheric Chemistry and Physics 5, n. 1 (2 febbraio 2005): 249–73. http://dx.doi.org/10.5194/acp-5-249-2005.
Abstract (sommario):
Abstract. The measurement of atmospheric concentrations by a monitoring network is a promising tool for the identification of the widespread sources of trace species. The paper addresses the case of the species scattered linearly by a known meteorology. The question is classical: what can be said about the source from a set of measurements? Is it possible to guess from the values observed by the measurements that the source is spread close to the detectors, or that the tracer comes from a remote region? And, if the source was a point source, would it be possible to understand it by just considering these values? A part of the answers is a matter of practical sense: the resolution with which an emission can be retrieved will always be limited and probably lower for a remote region, even if the detectors and dispersion model are error free. The paper proposes a linear strategy of inference: to any set of values taken by the observed concentrations is associated linearly an estimate of the source. Doubled values lead to a doubled estimate. The method, based on adjoint techniques, is intended to optimise the resolution by quantifying, with the concept of illumination, which regions are well, poorly or not seen at all. The illumination tied to ordinary adjoint functions becomes excessive close to the detectors thus leading to inversion artefacts. This may be corrected by attributing each point of the space time domain a geometric and statistical weight. The adjoint functions are transformed. The choice of this renormalising function is constrained by an unambiguous entropic criterion preventing any overestimation of the available information that would lead to artefacts. It amounts to evenly distribute the information between the points organised with their weights as a "known domain". The theory is illustrated by calculations performed with the experimental source ETEX1.
42
Genies, Sylvie, Pierre Balfet, Elise Villemin, Cédric Septet, Marco Ranieri, Romain Franchi e Olivier Raccurt. "Why Li(1-x)FePO4/ LiFePO4 Is a Good Candidate to be Used as Reference Electrode". ECS Meeting Abstracts MA2023-02, n. 2 (22 dicembre 2023): 330. http://dx.doi.org/10.1149/ma2023-022330mtgabs.
Abstract (sommario):
Fundamental electrochemical studies require the implementation of a reference electrode inside the cell to record the potential profile and characterize the kinetic properties as well as the interface structure of each electrode [1]. Obtaining such data is essential for a better understanding of the electrochemical processes and the aging mechanisms generated by cycling. This is challenging for lithium-ion technologies for which no reference electrode is commercially available. LixFePO4 (LFP), a biphasic material, has been identified as a possible reference material, because its insertion/de-insertion curves show a voltage plateau over a wide lithiation range (Figure 1). Literature reports studies of instrumented pouch cells with a reference electrode in LFP [2, 3]. One important criterion to consider is the stability of the potential of LFP over time and the impact of temperature on the potential in the perspective to develop innovative smart-cell. The response will be provided according to the stability study of the Li0.5FePO4 potential. The methodology, used to evaluate the operating time of the reference electrode in LFP is based on monitoring the open circuit potential (OCV) of Li0.5FePO4 versus lithium over time and at different temperatures. The used cell configuration used is illustrated in Figure 2. We will also present the entropic behaviour of LFP which will confirm why LFP is a good candidate for reference electrode. REFERENCES: [1] Electroanalytical Methods Guide to Experiments and Applications, Springer; Edition: 2nd ed. 2010 (11 November 2014) [2] I. Jiménez Gordon, S. Grugeon, A. Débart, G. Pascaly, S. Laruelle, Solid State Ionics 237 (2013) 50–55 [3] F. La Mantia, C.D. Wessells, H.D. Deshazer, Yi Cui, Electrochemistry Communications, Vol. 31,2013, 141-144 ACKNOWLEDGMENTS: INSTABAT project has received funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No 955930. Figure 1
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Kovalenko, O. Ye, e V. L. Kosolapov. "Stability model of agent-based situational control system". Mathematical machines and systems 3 (2020): 93–104. http://dx.doi.org/10.34121/1028-9763-2020-3-93-104.
Abstract (sommario):
While managing complex systems, it is advisable to use mathematical models adequate to real systems, which can be used for generalized model analysis of different solutions in systems of situational man-agement (SSM). Such mathematical models are an important component of the SSM in the process of supporting the adoption of important strategic and operational decisions at various levels of government. Implementation of SSM in the form of a multi-agent system, due to its characteristics, is an adequate approach to solving the problems of situational management (SM). According to the context of SM, the behavior of the SSM is described as the dynamics of movement from a certain point in the phase space, that corresponds to some state of the managed system under the influence of the ensemble of SSM agents. During the operation of the SSM, its agents use knowledge that corresponds to the context of the situation. The agent's knowledge is a fragment of the field of knowledge on the target problem of SM. Knowledge of the problem area of the SM is a key element of the SM model. The convergent agents’ ensemble of SSM is characterized by a certain level of intelligence, which is represented as an entropic force that uses the free energy of the dissipative system to maintain its stability. An agent-oriented approach to the study of the stability of a dynamic stochastic system in the process of situa-tional management as a target project activity is proposed. Within the scope of the proposed approach, the stability model of agent SSM as a dynamic stochastic system is considered using the Lyapunov sta-bility criterion in the form of a system of ordinary differential equations. Support of modeling functions by agents of agent-oriented system allows to form adequate behavior in the process of situational man-agement in the conditions of changes in the environment. Developed models for integrating behavioral and coordination aspects of knowledge-based agents can be used in the development of situational man-agement systems and technologies.
44
Yan, Zhi-Chao, Chandra Sekhar Biswas e Florian J. Stadler. "Rheological Study on the Thermoreversible Gelation of Stereo-Controlled Poly(N-Isopropylacrylamide) in an Imidazolium Ionic Liquid". Polymers 11, n. 5 (2 maggio 2019): 783. http://dx.doi.org/10.3390/polym11050783.
Abstract (sommario):
The thermoreversible sol-gel transition for an ionic liquid (IL) solution of isotactic-rich poly (N-isopropylacrylamides) (PNIPAMs) is investigated by rheological technique. The meso-diad content of PNIPAMs ranges between 47% and 79%, and molecular weight (Mn) is ~35,000 and ~70,000 g/mol for two series of samples. PNIPAMs are soluble in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl) imide ([BMIM][TFSI]) at high temperatures but undergo a gelation with decreasing temperatures. The transition temperature determined from G’-G” crossover increases with isotacticity, consistent with the previous cloud-point result at the same scanning rate, indicating imide groups along the same side of backbones are prone to be aggregated for formation of a gel. The transition point based on Winter-Chambon criterion is on average higher than that of the G’-G” crossover method and is insensitive to tacticity and molecular weight, since it correlates with percolation of globules rather than the further formation of elastic network (G’ > G”). For the first time, the phase diagram composed of both G’-G” crossover points for gelation and cloud points is established in PNIPAM/IL mixtures. For low-Mn PNIPAMs, the crossover-point line intersects the cloud-point line. Hence, from solution to opaque gel, the sample will experience two different transitional phases, either clear gel or opaque sol. A clear gel is formed due to partial phase separation of isotactic segments that could act as junctions of network. However, when the partial phase separation is not faster than the formation of globules, an opaque sol will be formed. For high-Mn PNIPAMs, crossover points are below cloud points at all concentrations, so their gelation only follows the opaque sol route. Such phase diagram is attributed to the poorer solubility of high-Mn polymers for entropic reasons. The phase diagram composed of Winter-Chambon melting points, crossover points for melting, and clear points is similar with the gelation phase diagram, confirming the mechanism above.
45
Gao, Hongmin, Yao Yang, Xiaoke Zhang, Chenming Li, Qi Yang e Yongchang Wang. "Dimension Reduction for Hyperspectral Remote Sensor Data Based on Multi-Objective Particle Swarm Optimization Algorithm and Game Theory". Sensors 19, n. 6 (16 marzo 2019): 1327. http://dx.doi.org/10.3390/s19061327.
Abstract (sommario):
Information entropy and interclass separability are adopted as the evaluation criteria of dimension reduction for hyperspectral remote sensor data. However, it is rather single-faceted to simply use either information entropy or interclass separability as evaluation criteria, and will lead to a single-target problem. In this case, the chosen optimal band combination may be unfavorable for the improvement of follow-up classification accuracy. Thus, in this work, inter-band correlation is considered as the premise, and information entropy and interclass separability are synthesized as the evaluation criterion of dimension reduction. The multi-objective particle swarm optimization algorithm is easy to implement and characterized by rapid convergence. It is adopted to search for the optimal band combination. In addition, game theory is also introduced to dimension reduction to coordinate potential conflicts when both information entropy and interclass separability are used to search for the optimal band combination. Experimental results reveal that compared with the dimensionality reduction method, which only uses information entropy or Bhattacharyya distance as the evaluation criterion, and the method combining multiple criterions into one by weighting, the proposed method achieves global optimum more easily, and then obtains a better band combination and possess higher classification accuracy.
46
Lavenda, B. H. "Entropies of Mixing (EOM) and the Lorenz Order". Open Systems & Information Dynamics 13, n. 01 (marzo 2006): 75–90. http://dx.doi.org/10.1007/s11080-006-7269-2.
Abstract (sommario):
Polynomial nonadditive, or pseudo-additive (PAE), entropies are related to the Shannon entropy in that both are derived from two classes of parent distributions of extreme-value theory, the Pareto and power distributions. The third class is the exponential distribution, corresponding to the Shannon entropy, to which the other two tend as their shape parameters increase without limit. These entropies all belong to a single class of entropies referred to as EOM. EOM is defined as the normalized difference between the dual of the Lorentz function and the Lorenz function. Sufficient conditions for majorization involve finding a separable, Schur-concave function, like the EOM, which increases as the distribution becomes more uniform or less spread out. Lorenz ordering has been associated to the degree in which the Lorenz curve is bent. This criterion is valid for tail distributions, and fails in the case where the distribution is limited on the right. EOM provide criteria for inequality in the Lorenz ordering sense: In the Pareto case, an increase in the shape parameter implies a decrease in inequality and the EOM decreases, whereas for the power distribution an increase in the shape parameter corresponds to an increase in inequality leading to an increase in the EOM. An analogy is drawn between Gauss' invariant distribution for the probability of the fractional part of a continued fraction and the area criterion in Lorenz ordering, analogous to the Gini index criterion. The tendency to approach the invariant distribution, as the number of partial quotients increases without limit, is shown to be analogous to the tendency to approach the invariant area, as the shape parameters increase without limit.
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Zaichenko, Stefan V., Kostiantyn I. Pochka, Yurii O. Romasevych, Vadym O. Shalenko, Roman D. Kulish e Maksym M. Balaka. "Determination of Elements Reliability for Power Plants Based on Internal Combustion Engines by Lowest Residual Entropy Method". Journal of Mechanical Engineering 26, n. 1 (30 marzo 2023): 39–45. http://dx.doi.org/10.15407/pmach2023.01.039.
Abstract (sommario):
The selection technique of diagnostic parameters for the creation of fault detection system of autonomous electric power sources based on gasoline and diesel engines is given in the paper. An analysis of the design features for autonomous electric power sources based on internal combustion engines, which are the most common on the Ukrainian market, was carried out. Thanks to this, a logical model of the research object, which establishes the relation between the main structural elements of the system and determines the possible states of the system, was developed. The effect of fault state initiation for each element on the other system elements was analyzed. An informative criterion – Shannon information entropy is proposed to determine the finite number of diagnostic parameters among the infinite number of possible combinations for physical parameters that characterize the system. The equal-probable cases of exit from operational state of each system elements are considered. The residual entropies of the system at the fault state for one of the autonomous power sources assembly are determined, having applied the concept of Shannon information entropy. The residual entropy value is the informative criterion. The application of this criterion allowed to determine the system elements that most effectively reduce the system uncertainty degree. Based on the residual entropy values, the system assemblies, the state of which should be primarily monitored by diagnostic system, are selected. The diagnostic parameters are determined for such elements, and the ways to obtain them are given
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INAGAKI, Atsushi. "ENTROMIN AND ENTROMAX: CRITERIA FOR FACTOR ROTATION BASED ON ENTROPY". Kodo Keiryogaku (The Japanese Journal of Behaviormetrics) 21, n. 2 (1994): 10–20. http://dx.doi.org/10.2333/jbhmk.21.2_10.
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Arellano, Aldo Ramirez, Juan Bory-Reyes e Luis Manuel Hernandez-Simon. "Statistical Entropy Measures in C4.5 Trees". International Journal of Data Warehousing and Mining 14, n. 1 (gennaio 2018): 1–14. http://dx.doi.org/10.4018/ijdwm.2018010101.
Abstract (sommario):
The main goal of this article is to present a statistical study of decision tree learning algorithms based on the measures of different parametric entropies. Partial empirical evidence is presented to support the conjecture that the parameter adjusting of different entropy measures might bias the classification. Here, the receiver operating characteristic (ROC) curve analysis, precisely, the area under the ROC curve (AURC) gives the best criterion to evaluate decision trees based on parametric entropies. The authors emphasize that the improvement of the AURC relies on of the type of each dataset. The results support the hypothesis that parametric algorithms are useful for datasets with numeric and nominal, but not for mixed, attributes; thus, four hybrid approaches are proposed. The hybrid algorithm, which is based on Renyi entropy, is suitable for nominal, numeric, and mixed datasets. Moreover, it requires less time when the number of nodes is reduced, when the AURC is maintaining or increasing, thus it is preferable in large datasets.
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PRONZATO, L., H. P. WYNN e A. A. ZHIGLJAVSKY. "Stochastic Analysis of Convergence via Dynamic Representation for a Class of Line-search Algorithms". Combinatorics, Probability and Computing 6, n. 2 (giugno 1997): 205–29. http://dx.doi.org/10.1017/s096354839600288x.
Abstract (sommario):
Certain convergent search algorithms can be turned into chaotic dynamic systems by renormalisation back to a standard region at each iteration. This allows the machinery of ergodic theory to be used for a new probabilistic analysis of their behaviour. Rates of convergence can be redefined in terms of various entropies and ergodic characteristics (Kolmogorov and Rényi entropies and Lyapunov exponent). A special class of line-search algorithms, which contains the Golden-Section algorithm, is studied in detail. Their associated dynamic systems exhibit a Markov partition property, from which invariant measures and ergodic characteristics can be computed. A case is made that the Rényi entropy is the most appropriate convergence criterion in this environment.