• Bulletin of the Korean Chemical Society
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• v.31 no.5
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• pp.1247-1251
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• 2010

We propose an improved solvent contact model to estimate the solvation free energies of amino acids from individual atomic contributions. The modification of the solvation model involves the optimization of three kinds of parameters in the solvation free energy function: atomic fragmental volume, maximum atomic occupancy, and atomic solvation parameters. All of these atomic parameters for 17 atom types are developed by the operation of a standard genetic algorithm in such a way to minimize the difference between experimental and calculated solvation free energies. The present solvation model is able to predict the experimental solvation free energies of amino acids with the squared correlation coefficients of 0.94 and 0.93 for the parameterization with Gaussian and screened Coulomb potential as the envelope functions, respectively. This result indicates that the improved solvent contact model with the newly developed atomic parameters would be a useful tool for the estimation of the molecular solvation free energy of a protein in aqueous solution.

• The Journal of the Acoustical Society of Korea
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• v.6 no.3
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• pp.31-42
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• 1987

An ultrasonic pulse-echo diagnostic system for tissue characterization with the estimation of attenuation coefficients is developed and its performance has been examined by system implementation. The system divided into the ultrasonic generator, A/D converter, data communication, computer for signal processing. The methods for estimating the spatial distribution of acoustic attenuation coefficients using the moment analysis are proposed. The experimental results indicate the potential of the methods for tissue characterization.

• Journal of the Korean Society of Industry Convergence
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• v.4 no.4
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• pp.387-393
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• 2001

The flow characteristics on the centerline in case of free jet, sudden expansion jet and impinging jet have been investigated. Centerline flow behaviors and similaritis with mean velocities, turbulent intensities, shear stresses, isotropic structures and turbulent kinetic energies on the streamwise direction were looked into and compared with three jets, The results show that mean velocities have represented potential core and decayed with similar gradients. The turbulent intensities and shear stresses were presented peak values in the self-preserving region, and then they were in decay. Aeolotropy in the initial region were possible returned to isotropy patterns with asymptotic approach in the downstream region. It has been found that the turbulent kinetic energies for the three cases of jet existed in the similarity and they coincided with Gaussian profile.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2287-2289
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• 1999

In this paper, a new method for calculating capacitance in multi-electrode system with arbitrarily shape is presented. This new approach based on divergence theorem and Gauss's law is achieved by Surface-Contacted Element(SCE) for Gaussian surface. To evaluate capacitance in multi-electrode system, two dimensional finite element method using only the elements which is contacted one nod (PE: Point-Element) or two nod (FE: Face-Element) with surface is employed. The proposed SCE method has short computing time to calculate capacitance which is because it uses only SCE elements and needs one calculation loop while exiting FEM method in servral loops. This method is verified by application in calculating capacitance using potential detection device model which is composed with anode, cathode, and floating electrode.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.43.4-44
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• 2009

electron, ion, heavy ion으로 구성 된 plasma에서 hump type과 kink type(double layer)의 electrostatic solitary waves이 존재할 수 있다는 것을 pseudopotential method를 이용한 결과와 1d PIC(Particle-In-Cell) simulation method의 결과에서 각각 확인하였다. 1d PIC simulation에서 초기에 각각의 입자 종(species; electron, ion, heavy ion)의 밀도섭동(density perturbation)은 Gaussian 형태로 주었으며, 각각의 입자들의 drift velocity는 각각의 plasma 입자 종들의 thermal velocity로 나란한 방향으로 주었다.

• ETRI Journal
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• v.9 no.3
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• pp.3-12
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• 1987

In this paper, a non-classical autocorrelation detector adopting a newly defined test statistic is introduced to solve the typical problem of detecting a narrowband signal transmitted over an additive white Gaussian noise (AWGN) channel. Error probability analyses are performed for a noncoherent frequency-shift-keying (FSK) system employing the proposed test-statistic. Through the histogram approach, the probability density functions of the test-statistics are plotted to explain the analysis model. All numerical results obtained indicate the limited improvement in error performance under the lower signal-to-noise ratio (SNR) and the use of higher number of samples per bit will finally provide the almost same confident potential of improvement in error rate as the system using matched filters (MFs) gives.

• ETRI Journal
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• v.26 no.5
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• pp.413-422
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• 2004

This paper investigates the impacts of array weight errors (AWE) in an antenna array (AA) on a parallel interference cancellation (PIC) receiver in uplink synchronous and asynchronous direct sequence code division multiple access (DS-CDMA) systems. The performance degradation due to an AWE, which is approximated by a Gaussian distributed random variable, is estimated as a function of the variance of the AWE. Theoretical analysis, confirmed by simulation, demonstrates the tradeoffs encountered between system parameters such as the number of antennas and the variance of the AWE in terms of the achievable average bit error rate and the user capacity. Numerical results show that the performance of the PIC with the AA in the DS-CDMA uplink is sensitive to the AWE. However, either a larger number of antennas or uplink synchronous transmissions have the potential of reducing the overall sensitivity, and thus improving its performance.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4098-4102
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• 2012

The potential energy surface (PES) for the loss of HCN from the pyrimidine molecular ion has been explored using quantum chemical calculations. Possible reaction pathways to form five $C_3H_3N^{+{\bullet}}$ isomers have been obtained with Gaussian 4 model calculations. The rate constant for the HCN loss and the product branching ratio have been calculated using the Rice-Ramsperger-Kassel-Marcus theory on the basis of the obtained PES. The resultant rate constant agrees with the previous experimental result. By a kinetic analysis, it is proposed that the formation of $CH=CHC{\equiv}NH^{+{\bullet}}$ is favored near the dissociation threshold, while the formation of $CH=CHN{\equiv}CH^{+{\bullet}}$ is favored at high energies.

• Bulletin of the Korean Chemical Society
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• v.31 no.12
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• pp.3718-3722
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• 2010

Theoretical investigations are carried out on the title reaction by means of ab-initio and DFT methods. The optimized geometries, frequencies and minimum energy path are obtained at UB3LYP/6-311G(d,p) level. Single point energy calculations are performed at MP2 and MP4 levels of theory. Energetics are further refined by calculating the energy of the species with a modified Gaussian-2 method, G2M(CC,MP2). The rate constant of the reaction is calculated using Canonical Transition State Theory (CTST) utilizing the ab-initio data obtained during the present study and is found to be $5.47{\times}10^{-12}\;cm^3\;molecule^{-1}s^{-1}$ at 298 K and 1 atm.

• Journal of Information Processing Systems
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• v.14 no.1
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• pp.218-227
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• 2018

Vocal effort detection is important for both robust speech recognition and speaker recognition. In this paper, the spectral information entropy feature which contains more salient information regarding the vocal effort level is firstly proposed. Then, the model fusion method based on complementary model is presented to recognize vocal effort level. Experiments are conducted on isolated words test set, and the results show the spectral information entropy has the best performance among the three kinds of features. Meanwhile, the recognition accuracy of all vocal effort levels reaches 81.6%. Thus, potential of the proposed method is demonstrated.