• Title/Summary/Keyword: Differential entropy

Search Result 49, Processing Time 0.036 seconds

A Comparison on the Differential Entropy

  • Kim, Dae-Hak
    • Journal of the Korean Data and Information Science Society
    • /
    • v.16 no.3
    • /
    • pp.705-712
    • /
    • 2005
  • Entropy is the basic concept of information theory. It is well defined for random varibles with known probability density function(pdf). For given data with unknown pdf, entropy should be estimated. Usually, estimation of entropy is based on the approximations. In this paper, we consider a kernel based approximation and compare it to the cumulant approximation method for several distributions. Monte carlo simulation for various sample size is conducted.

  • PDF

Security Analysis based on Differential Entropy m 3D Model Hashing (3D 모델 해싱의 미분 엔트로피 기반 보안성 분석)

  • Lee, Suk-Hwan;Kwon, Ki-Ryong
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.35 no.12C
    • /
    • pp.995-1003
    • /
    • 2010
  • The content-based hashing for authentication and copy protection of image, video and 3D model has to satisfy the robustness and the security. For the security analysis of the hash value, the modelling method based on differential entropy had been presented. But this modelling can be only applied to the image hashing. This paper presents the modelling for the security analysis of the hash feature value in 3D model hashing based on differential entropy. The proposed security analysis modeling design the feature extracting methods of two types and then analyze the security of two feature values by using differential entropy modelling. In our experiment, we evaluated the security of feature extracting methods of two types and discussed about the trade-off relation of the security and the robustness of hash value.

PERELMAN TYPE ENTROPY FORMULAE AND DIFFERENTIAL HARNACK ESTIMATES FOR WEIGHTED DOUBLY NONLINEAR DIFFUSION EQUATIONS UNDER CURVATURE DIMENSION CONDITION

  • Wang, Yu-Zhao
    • Bulletin of the Korean Mathematical Society
    • /
    • v.58 no.6
    • /
    • pp.1539-1561
    • /
    • 2021
  • We prove Perelman type 𝒲-entropy formulae and differential Harnack estimates for positive solutions to weighed doubly nonlinear diffusion equation on weighted Riemannian manifolds with CD(-K, m) condition for some K ≥ 0 and m ≥ n, which are also new for the non-weighted case. As applications, we derive some Harnack inequalities.

Entropy analysis in a cilia transport of nanofluid under the influence of magnetic field

  • Abrar, Muhammad N.;Haq, Rizwan Ul;Awais, Muhammad;Rashid, Irfan
    • Nuclear Engineering and Technology
    • /
    • v.49 no.8
    • /
    • pp.1680-1688
    • /
    • 2017
  • In this study, analysis is performed on entropy generation during cilia transport of water based titanium dioxide nanoparticles in the presence of viscous dissipation. Moreover, thermal heat flux is considered at the surface of a channel with ciliated walls. Mathematical formulation is constructed in the form of nonlinear partial differential equations. Making use of suitable variables, the set of partial differential equations is reduced to coupled nonlinear ordinary differential equations. Closed form exact solutions are obtained for velocity, temperature, and pressure gradient. Graphical illustrations for emerging flow parameters, such as Hartmann number (Ha), Brinkmann number (Br), radiation parameter (Rn), and flow rate, have been prepared in order to capture the physical behavior of these parameters. The main goal (i.e., the minimizing of entropy generation) of the second law of thermodynamics can be achieved by decreasing the magnitude of Br, Ha and ${\Lambda}$ parameters.

SOME PROPERTIES OF MUTUAL INFORMATION AND TYPICAL SET

  • LEE, YOUNG SOO
    • Journal of the Korean Society for Industrial and Applied Mathematics
    • /
    • v.4 no.1
    • /
    • pp.133-142
    • /
    • 2000
  • In this note we define typical set and differential entropy for continuous random variables. Using Markov chain, we show that the various properties of the mutual information and entropies (theorems 3.2 and 3.4 ) and show the properties of typical set in continuous random variables( lemma 4.2 and theorem 4.3.)

  • PDF

Decreased entropy of unfolding increases the temperature of maximum stability: Thermodynamic stability of a thioredoxin from the hyperthermophilic archaeon Methanococcus jannaschii

  • Lee, Duck-Yeon;Kim, Kyeong-Ae;Kim, Key-Sun
    • Journal of the Korean Magnetic Resonance Society
    • /
    • v.8 no.1
    • /
    • pp.1-18
    • /
    • 2004
  • A thioredoxin from hyperthermophile, Methanococcus jannashii (MjTRX) was characterized by use of the differential scanning calorimetry to understand the mechanisms of thermodynamic stability. MjTRX has an unfolding transition temperature of 116.5$^{\circ}C$, although the maximum free energy of the unfolding (9.9 Kcal/mol) is similar to that of E. coli thioredoxin (ETRX, 9.0 Kcal/mol). However, the temperature of maximum stability is higher than ETRX by 20$^{\circ}C$, indicating that the unfolding transition temperature increased by shifting the temperature of maximum stability. MjTRX has lower enthalpy and entropy of the unfolding compared to ETRX maintaining a similar free energy of the unfolding. From the structure and the thermodynamic parameters of MjTRX, we showed that the unfolding transition temperature of MjTRX is increased due to the decreased entropy of the unfolding. Decreasing the unfolded state entropy and increasing the folded state entropy can decrease the entropy of the unfolding. In the case of MjTRX, the increased number of proline residues decreased the unfolded state entropy and the increased enthalpy in the folded state increased the folded state entropy.

  • PDF

Entropy Generation Minimization in MHD Boundary Layer Flow over a Slendering Stretching Sheet in the Presence of Frictional and Joule Heating

  • Afridi, Muhammad Idrees;Qasim, Muhammad;Khan, Ilyas
    • Journal of the Korean Physical Society
    • /
    • v.73 no.9
    • /
    • pp.1303-1309
    • /
    • 2018
  • In the present paper, we study the entropy analysis of boundary layer flow over a slender stretching sheet under the action of a non uniform magnetic field that is acting perpendicular to the flow direction. The effects of viscous dissipation and Joule heating are included in the energy equation. Using similarity transformation technique the momentum and thermal boundary layer equations to a system of nonlinear differential equations. Numerical solutions are obtained using the shooting and fourth-order Runge-Kutta method. The expressions for the entropy generation number and Bejan number are also obtained using a suggested similarity transformation. The main objective of this article is to investigate the effects of different governing parameters such as the magnetic parameter ($M^2$), Prandtl number (Pr), Eckert number (Ec), velocity index parameter (m), wall thickness parameter (${\alpha}$), temperature difference parameter (${\Omega}$), entropy generation number (Ns) and Bejan number (Be). All these effects are portrayed graphically and discussed in detail. The analysis reveals that entropy generation reduces with decreasing wall thickness parameter and increasing temperature difference between the stretching sheet and the fluid outside the boundary layer. The viscous and magnetic irreversibilities are dominant in the vicinity of the stretching surface.

Synthesis of Novel (Be,Mg,Ca,Sr,Zn,Ni)3O4 High Entropy Oxide with Characterization of Structural and Functional Properties and Electrochemical Applications

  • Arshad, Javeria;Janjua, Naveed Kausar;Raza, Rizwan
    • Journal of Electrochemical Science and Technology
    • /
    • v.12 no.1
    • /
    • pp.112-125
    • /
    • 2021
  • The new emerging "High entropy materials" attract the attention of the scientific society because of their simpler structure and spectacular applications in many fields. A novel nanocrystalline high entropy (Be,Mg,Ca,Sr,Zn,Ni)3O4 oxide has been successfully synthesized through mechanochemical treatment followed by sintering and air quenching. The present research work focuses on the possibility of single-phase formation in the aforementioned high entropy oxide despite the great difference in the atomic sizes of reactant alkaline earth and 3d transition metal oxides. Structural properties of (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide were explored by confirmation of its single-phase Fd-3m spinel structure by x-ray diffraction (XRD). Further, nanocrystalline nature and morphology were analyzed by scanning electron microscopy (SEM). Among thermal properties, thermogravimetric analysis (TGA) revealed that the (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide is thermally stable up to a temperature of 1200℃. Whereas phase evolution in (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide before and after sintering was analyzed through differential scanning calorimetry (DSC). Electrochemical studies of (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide consists of a comparison of thermodynamic and kinetic parameters of water and hydrazine hydrate oxidation. Values of activation energy for water oxidation (9.31 kJ mol-1) and hydrazine hydrate oxidation (13.93 kJ mol-1) reveal that (Be,Mg,Ca,Sr,Zn,Ni)3O4 high entropy oxide is catalytically more active towards water oxidation as compared to that of hydrazine hydrate oxidation. Electrochemical impedance spectroscopy is also performed to get insight into the kinetics of both types of reactions.

Numerical Study of Entropy Generation with Nonlinear Thermal Radiation on Magnetohydrodynamics non-Newtonian Nanofluid Through a Porous Shrinking Sheet

  • Bhatti, M.M.;Abbas, T.;Rashidi, M.M.
    • Journal of Magnetics
    • /
    • v.21 no.3
    • /
    • pp.468-475
    • /
    • 2016
  • In this article, entropy generation on MHD Williamson nanofluid over a porous shrinking sheet has been analyzed. Nonlinear thermal radiation and chemical reaction effects are also taken into account with the help of energy and concentration equation. The fluid is electrically conducting by an external applied magnetic field while the induced magnetic field is assumed to be negligible due to small magnetic Reynolds number. The governing equations are first converted into the dimensionless expression with the help of similarity transformation variables. The solution of the highly nonlinear coupled ordinary differential equation has been obtained with the combination of Successive linearization method (SLM) and Chebyshev spectral collocation method. Influence of all the emerging parameters on entropy profile, temperature profile and concentration profile are plotted and discussed. Nusselt number and Sherwood number are also computed and analyzed. It is observed that entropy profile increases for all the physical parameters. Moreover, it is found that when the fluid depicts non-Newtonian (Williamson fluid) behavior then it causes reduction in the velocity of fluid, however, non-Newtonian behavior enhances the temperature and nanoparticle concentration profile.

Multi-Valued Image Entropy Coding for input-width reduction of LCD source drivers

  • Sasaki, Hisashi;Arai, Tooru;Hachiuma, Masayuki;Masuko, Akira;Taguchi, Takashi
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2004.08a
    • /
    • pp.149-152
    • /
    • 2004
  • A new joint source channel coding reduces both input-width and average current consumption to transmit image data to LCD source drivers. As a source coding, it is based on entropy coding of differential pulse code modulation scheme, especially using median edge detector of image predictor. As a channel coding, it is not a simple pulse amplitude modulation, but linked by source entropy to reduce average amplitude. Simulation results show 1/4 width is achievable by 16-valued transmission with keeping conventional current consumption (0.36 to 1.3).

  • PDF