• The Pure and Applied Mathematics
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• v.19 no.1
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• pp.73-86
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• 2012

This is a survey on the volume entropy and its rigidity of various metric spaces. This survey is aimed to summarize recent results as well as remaining open questions and possible directions on this subject.

• Communications of the Korean Mathematical Society
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• v.10 no.2
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• pp.365-374
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• 1995

On a compact manifold without conjugate points, the volume entropy can be obtained as the average mean curvature of the horospheres in the universal covering space. In the case when the volume entropy is zero, we prove that the universal covering space is diffeomorphic to a product space with a line factor. This fact can be considered as a surporting evidence for the Mane's conjecture, which claims the flatness of the mainfold.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.157-164
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• 2008

The temperature-entropy diagram of water or vapor displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. On general T-s chart of water, there are temperature, pressure, quality, specific volume, specific enthalpy, specific entropy. However, various state and process values besides above properties can be plotted on T-s diagram. In this study, we developed the software drawing twenty six kinds of properties, that is temperature, pressure, quality, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, coefficient of viscosity, kinematic coefficient of viscosity, thermal conductivity, prandtl number, ion product, static dielectric constant, isentropic exponent, velocity of sound, joule-thomson coefficient, pressure coefficient, volumetric coefficient of expansion, isentropic compressibility, and isothermal compressibility. Also, this software can analyze and print the system values of mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, and reversible work. Additionally, this software support the functions such as MS-Power Point.

• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.277-286
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• 2009

Image registration is a process to establish the spatial correspondence between images of the same scene, which are acquired at different view points, at different times, or by different sensors. In this paper, we introduce a robust brain registration technique for correcting the difference between two temporal images by the different coordinate systems in MR and CT image obtained from the same patient. Two images are registered where this measure is minimized using a modified conditional entropy(MCE: Modified Conditional Entropy) computed from the joint histograms for the intensities of two given images, we conduct the rendering for visualization of 3D volume image.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.59-60
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• 2007

Entropy, one of leading metrics on anomalous traffic, attracts researcher's attention since a packet sampling and a traffic volume impact little on entropy value. In this paper, we apply the entropy metric to a domestic network traffic trace which has real anomalous traffics. We used source IP address/port and destination IP address/port that are important attributes of a packet as entropy variable We found that entropy value of multiple-port DoS attack shows something related to a staircase fashion. Also, we show a Possibility of detection of anomalous traffic on small time scale.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.796-803
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• 1997

The PVT and $^2H$-NMR characteristic of main-chain dimer liquid crystals having structures such as ${\alpha}$, ${\omega}$-bis[4,4'-cyanobiphenyl) oxy] alkane(CBA-10) were studied. In this work, V-T curves obtained from isobaris measurements on various pressures, volume changes were observed at the nematic-isotropic and nematic-crystal phase transition. The volume changes at the transition exhibit slight odd-even effect with respect to the number of methylene unit n. The values of the$({\Delta}S_{tr})_V$ obtained at the NI transition for CBA-10 was $12.6J/mol{\cdot}K$. The values of $({\Delta}S_{CN})_V$ for the CN transition was estimated on the basis of DSC data : $65.3J/mol{\cdot}K$. For both transition, it was found that the correction about the volume change is significant, ranging from 40 to 60% of the total transition entropy observed under constant pressure. The RIS analysis of the spectra was performed so as to elucidate the conformational characteristics of the spacer in the nematic phase. The conformational entropy changes at both CN and NI interphases were estimated on the basis of the nematic conformations taken from the conformation map as well as those derived from the simulation. The estimated conformational entropy change values were then compared with the corresponding constant-volume entropies obtained from PVT measurements. The correspondence between both entropy values was found to be quite good in consideration of the uncertainties involved in both experiment and calculations.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1191-1196
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• 2009

The T-s chart of air displays graphically the thermophysical properties, so it is very conveniently used in various thermal systems. In previous study, the software analyzing 31 kinds of values in water system and 32 kinds of values in air-conditioning system were developed. In this study, the software drawing 13 kinds of quantity of state on air properties as ideal gas and analyzing 25 kinds of values in any air system was developed. The 13 kinds of quantity of state on air properties are temperature, pressure, specific volume, specific internal energy, specific enthalpy, specific entropy, specific exergy, exergy ratio, density, isobaric specific heat, isochoric specific heat, ratio of specific heat, and velocity of sound, and the 25 kinds of values including 13 kinds are mass flow rate, volume flow rate, internal energy flow rate, enthalpy flow rate, entropy flow rate, exergy flow rate, heat flow rate, power output, power efficiency, reversible work, lost work, and relative humidity. The developed software can draw any range of chart and analysis any state or process on air system. Also, this supports various document-editing functions such as power point. We wish to this chart is a help to design, analysis, and education in air system field.

• Nuclear Engineering and Technology
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• v.21 no.3
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• pp.193-204
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• 1989

This paper develops a new method for reconstructing neutron flux distribution, that is based on the maximum entropy Principle in information theory. The Probability distribution that maximizes the entropy Provides the most unbiased objective Probability distribution within the known partial information. The partial information are the assembly volume-averaged neutron flux, the surface-averaged neutron fluxes and the surface-averaged neutron currents, that are the results of the nodal calculation. The flux distribution on the boundary of a fuel assembly, which is the boundary condition for the neutron diffusion equation, is transformed into the probability distribution in the entropy expression. The most objective boundary flux distribution is deduced using the results of the nodal calculation by the maximum entropy method. This boundary flux distribution is then used as the boundary condition in a procedure of the imbedded heterogeneous assembly calculation to provide detailed flux distribution. The results of the new method applied to several PWR benchmark problem assemblies show that the reconstruction errors are comparable with those of the form function methods in inner region of the assembly while they are relatively large near the boundary of the assembly. The incorporation of the surface-averaged neutron currents in the constraint information (that is not done in the present study) should provide better results.

• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.20-27
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• 2012

Complex permittivity spectra of Allyl Chloride (AC), 2-Butanone (2-BU) and their binary mixtures over the entire range of concentration were obtained using the Time Domain Reflectometry (TDR) technique in microwave frequency range at various temperatures. Static dielectric constant and relaxation time are obtained from complex permittivity spectra. Density ($\rho$) and refractive index ($n_D$) are also measured. These parameters are used to determine excess dielectric constant, excess inverse relaxation time, excess molar volume, excess molar refraction, polarity, Bruggeman factor and thermodynamic parameters viz. enthalpy of activation and entropy of activation. The values of static dielectric constant and relaxation time increases while density and refractive index decreases with the percentage of 2-Butanone in Allyl Chloride increases. Excess parameters were fitted to a Redlich-Kister equation.

• Journal of the Korean Chemical Society
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• v.20 no.6
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• pp.460-468
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• 1976

A theory of liquid water is developed by assuming that the molecules in the liquid state have solid-like and gas-like degrees of freedom. The spectroscopic data are used in assigning the vibrational frequencies of solid-like molecules. The calculated values of molar volume, vapor pressure, entropy, entropy of vaporization, expansion coefficient, compressibility, heat capacities at constant volume and at constant pressure, surface tension and critical point properties are all in excellent agreement with the observed data.