• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.475-478
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• 2005

Calculation of wear depth with regard to the wear topology is peformed numerically Four typical wear topology, that is round, crescent, flat, and diamond types are adopted to represent the configuration of wear volume. Diamond and flat types are the most severe topology for wear depth history, whereas round and crescent types have small increasing rate of wear depth to the wear volume. Based on this study we can guess that the most severe wear phenomena happens to be upper side of U-tubes in the KSNP SG, because flat or diamond wear will be generated by the wearing motion between tubes and diagonal, vertical, horizontal strips. The misalignment of tube at the stage of manufacturing or distortion of upper structure due to the thermal expansion or vibration of upper structure such as diagonal, vertical, and horizontal strips will be one of the main causes of flat or diamond wear.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1275-1280
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• 2016

This research is for the visualization of wooden cracking phenomena in the virtual world. Timber supplies has been traditionally used for buildings in the all over the world. Wood has a characteristic that is more prone to be influenced and distorted under the external environments compared with other materials like as stone and concrete. Many related researches say that moisture content change is a largest impact factor for the distortion and crack of timber supplies. This is the reason why we focus on the relationship between the moisture variations and the wood distortion, especially crack. In this research, it is mathematically explained that the diminutions of tensile strength caused by repeated contraction and expansion according to the moisture variations under the changes of weather. Finally, we suggest a way to visualize it for pine timbers.

• Journal of the Korea Computer Industry Society
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• v.3 no.3
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• pp.407-412
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• 2002

With the increasing availability of information in electronic form, it becomes more important and feasible to have automatic methods to retrieve relevant information in the internet. A deficiency of traditional information retrieval systems is that search terms are often different from those indexed by the systems. Thus, user may either retrieve wrong information or miss what they really want. In this paper, we used an automatic query expansion based on term distribution to enhance the performance of information retrieval. Also this thesis proposed the method for setting the threshold according to area distribution in order to choose additional terns.

• Annual Conference of KIPS
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• 2015.10a
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• pp.634-636
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• 2015

As the expansion of enterprise scale and the increase of staff, the amount of terminal is increasing as well. It is very difficult to the system manager of traditional data protection scheme to manage and maintenance for the large number of terminals. This problem can be solved by desktop virtualization, which use traditional security problems still exist and new security problems occur at the same time. Using desktop virtualization, it needs a method of automatic security protection. In this paper, the desktop virtualization security requirements are discussed.

• Bulletin of the Korean Chemical Society
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• v.6 no.1
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• pp.3-7
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• 1985

The general formulas for SCF atomic orbitals |5s > and |6p > have been derived separately by expressing the spherical harmonics part in terms of the coordinate($r_1,\;$r_2$) of the reference point, and by translating the exponential part, $r^4\;exp\;(-{\beta}r)$), in terms of $r_1,\;and\;r_2$ and the modified Bessel functions. Master formulas for overlap and dipole moment matrix elements are derived. The computed values of overlap and dipole moment matrix elements for hypothetical NO molecule are exactly in agreement with those for the previous methods.

• Bulletin of the Korean Chemical Society
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• v.7 no.1
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• pp.6-12
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• 1986

Overlap integrals for the case in which the ground and excited states are represented by Morse potential functions were derived. In order to calculate the spectral intensities in Morse wavefunctions, a method of expanding the wavefunctions of one state in terms of the other was developed to allow the ground and the excited state frequencies to be different. From the expansion of Morse wavefunctions, recursion formulas were developed for variational matrix elements of Morse wavefunctions. The matrix elements can be calculated using these recursion formulas and the diagonalized results which eigenvalues (allowed energies) were all successfully satisfied to Morse energy formulas.

• Bulletin of the Korean Chemical Society
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• v.9 no.1
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• pp.36-40
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• 1988

The time correlation functions of concentration fluctuations due to the random forces near the steady state are evaluated for a general two-component nonlinear chemical system by solving the corresponding two dimensional Fokker-Planck equation. The approximate method of solving the Fokker-Planck equation is based on the eigenfunction expansion and the corresponding eigenvalues for both the linear and nonlinear Fokker-Planck operators are obtained near the steady state. The general results are applied to the Lotka model near the oscillatory marginal steady state and the comparison is made between linear and nonlinear cases.

• Bulletin of the Korean Chemical Society
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• v.5 no.3
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• pp.93-97
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• 1984

A general expression using the nonmultipole expansion method is derived for the NMR shift arising from 3d electron angular momentum and the 3d electron spin dipolar-nuclear spin angular momentum interactions for a 3$d^2$ system in a strong crystal field environment of octahedral symmetry when the threefold axis is chosen as the quantization axis. The NMR shift is separated to the contribution of constant, $1/R^5\;and\;1/R^7$ terms and compared with the multipolar terms. We find that $1/R^5$ term contributes dominantly to the NMR shift but the contribution of $1/R^7$ term may not be negligible. It is also found that the exact values of the NMR shift are in agreement with the multipolar results for distances larger than 0.35 nm.

• Bulletin of the Korean Chemical Society
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• v.15 no.6
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• pp.488-496
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• 1994

An approximate nonlinear theory of the Oregonator model is obtained with the aid of an ordinary perturbation method when the system is perturbed by some kinds of external input. The effects of internal and external parameters on the oscillations are discussed in detail by taking specific values of the parameters. A simple approximate solution for the Oregonator model under the influence of a constant input is obtained and the result is compared with the numerical result. For other types of external inputs the approximate solutions up to the fourth order expansion are compared with the numerical results. For a periodic input, we found that the entrainment depends crucially on the difference between the internal and external frequencies near the bifurcation point.

• Bulletin of the Korean Chemical Society
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• v.13 no.5
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• pp.560-565
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• 1992

A new perturbation theory called the star expansion method is used to obtain an approximate nonlinear solution of the Lotka-Volterra model under the influence of some kinds of external input. The effects of nonlinearity, amplitude and frequency of the external input on the chemical oscillations in the model are evaluated by taking specific values for the model parameters, and the results are discussed in detail.