• Journal of KIISE:Computer Systems and Theory
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• v.26 no.2
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• pp.211-222
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• 1999

본 논문은 위성간 링크를 이용하여 저궤도 위성망을 구성할 때 발생하는 링크할당 문제를 효율적으로 풀기 위한 기법을 제안한다. 제안된 기법은 먼저 위성 궤도운동의 주기성에 기반하여 저궤도 위성망을 유한상태기계로 모델링한 후에, 유한상태기계의 각 상태에서 최적의 링크할당을 구하기 위해서 조합형 최적화 문제에 많이 쓰이는 시뮬레이팅드 어닐리을 이용한다. 제안된 기법의 이점은 저궤도 위성망을 유한상태기계로 모델링함으로써 도적인 움직임을 보이는 저궤도 위성망에서의 링크할당 문제를 고정된 위상을 가지는 망에서의 링크할당 문제로 단순화시키고 이를 토대로 최적화기법을 적용할 수 있다는 것이다. 시뮬레이티드 어닐링에 의하여 최적화된 링크할당의 성능은 정규링크할당과의 비교.분석을 통해서 평가된다. 최적화된 링크할당과 정규링크할당의 성능분석을 위하여 정적경로배정과 동적경로배정 기법이 고려된다. 시뮬레이션을 통한 실험결과는 정적경로배정을 적용한 최적링크할당 기법이 호 봉쇄확률 측면에서 최고의 성능을 가짐을 보여준다. 링크할당기법이 같은 경우에는 정적경로배정이 동적경로배정보다 우수한 성능을 보이는데 이는 동적경로배정의 경우에 상태전이 후에 경로배정 표가 안정화되기 위해서 많은 시간을 필요로 하기 때문이다. 본 논문에서는 제안된 링크할당 기법은 작은 용량의 위성간 링크를 가지고서 많은 호에대한 서비스를 제공하고자 할 때 유용하며, 호의 서비스를 위하여 실제로 필요한 위성간 링크의 용량은 실험결과로부터 유추될 수 있다.

• Journal of the Korean Magnetic Resonance Society
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• v.9 no.1
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• pp.38-47
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• 2005

Axin is a scaffold protein of the APC/axin/GSK complex, binding to all of the other signalling components. Axin interacts with Glycogen synthase kinase 3$\beta$ (GSK 3$\beta$) and functions as a negative regulator of Wnt signalling pathways. To determine the solution structure of the GSK3$\beta$ binding regions of the axin, we initiated NMR study of axin fragment comprising residues 3$Val^{388} - Arg^{401}$using circular dichroism (CD) and two-dimensional NMR spectroscopy. The CD spectra of 3$axin^{pep}$ in the presence of 30% TFE displayed a standard 3$\alpha$-helical conformation, exhibiting the bound structure of 3$axin^{pep}$ to GSK3$\bata$. On the basis of experimental restraints including $NOE_s$, and $^3J_{HN\alpha} $ coupling constants, the solution conformation of $axin^{pep}$ was determined with program CNS. The 20 lowest energy structures were selected out of 50 final simulated-annealing structures in both water and TFE environment, respectively. The $RMSD_s$ for the 20 structures in TFE solution were 0.086 nm for backbone atoms and 0.195 nm for all heavy atoms, respectively. The Ramachandran plot indicates that the $\varphi$, $\psi$ angles of the 20 final structures is properly distributed in energetically acceptable regions. $Axin^pep$ in aqueous solutions consists of a stable $\alpha$-helix spanning residues form $Glu^{391}$ to $Val^{391} $, which is an interacting motif with GSK3$\beta$.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.4
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• pp.403-411
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• 2020

This paper discusses the main findings of the development of the twin-hull Car ferry for island freight and passenger transport. The final model had a 19 m wide beam to create enough space for cars on the deck area and thus, enhance the economic feasibility in the market. The vessel had a V-shape with a bulbous bow to minimize the wave-making resistance and the hydrodynamic performance of the ship was verified through computational fluid dynamics. Multi-objective optimization problems of Pareto simulated annealing were used to achieve a weight reduction of approximately 3.9 % and reduce the manufacturing cost. The main results obtained in this study are expected to be useful to engineers and professionals in related industries interested in research on twin catamaran.

• The Journal of the Acoustical Society of Korea
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• v.22 no.7
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• pp.562-572
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• 2003

A matched-target model inversion method was developed for a passive sonar to estimate the position of moving targets. Based on the well known matched-field processing in underwater acoustics, the method finds target position by matching the measured target directions and frequencies with the corresponding values of the proposed target model. For the efficient and accurate estimations, the parameter searching was accomplished using a hybrid optimizing method, which first starts with a global optimization such as generic algorithm or simulated annealing then applies a local optimization of a simple down hill algorithm. The suggested method was testified using simulations for three different moving scenarios. The simulation results showed that the method is robust in convergence, even under the situation of over 5 times standard deviation of Gaussian distribution of measured error, and is practical in calculation time as well.

• Transactions on Electrical and Electronic Materials
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• v.3 no.2
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• pp.10-15
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• 2002

In this paper, the electrical characteristics of fabricated p+-n junction diode are demonstrated and interpreted with different theoretical calculations. Dopants distribution by boron ion implantation on silicon wafer were simulated with TRIM-code and ICECaEM simulator. In order to make electrical activation of implanted carriers, thermal annealing treatments are carried out by RTP method for 1min. at $1000^{circ}C$ under inert $N_2$ gas condition. In this case, profiles of dopants distribution before and after heat treatments in the substrate are observed from computer simulations. In the I-V characteristics of fabricated diodes, an analytical description method of a new triangular junction model is demonstrated and the results with calculated triangular junction are compared with measured data and theoretical calculated results of abrupt junction. Forward voltage drop with new triangular junction model is lower than the case of abrupt junction model. In the C-V characteristics of diode, the calculated data are compared with the measured data. Another I-V characteristics of diodes are measured after proton implantation in electrical isolation method instead of conventional etching method. From the measured data, the turn-on characteristics after proton implantation is more improved than before proton implantation. Also the C-V characteristics of diode are compared with the measured data before proton implantation. From the results of measured data, reasonable deviations are showed. But the C-V characteristics of diode after proton implantation are deviated greatly from the calculated data because of leakage currents in defect regions and layer shift of depletion by proton implantation.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.146-149
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• 2002

The aim of stereotactic radiosurgery(SRS) is to deliver a high dose to a target region and a low dose to critical organ through only one or a few irradiation. To satisfy this aim, optimized irradiating conditions must be searched in the planning. Thus, many mathematical methods such as gradient method, simulated annealing and genetic algorithm had been proposed to find out the conditions automatically. There were some limitations using these methods: the long calculation time, and the difficulty of unique solution due to the different shape of tumor. In this study, optimization protocol using ideal models and data base was proposed. Proposed optimization protocol constitutes two steps. First step was a preliminary work. Some possible ideal geometry shapes, such as sphere, cylinder, cone shape or the combination, were assumed to approximate the real tumor shapes. Optimum variables such as isocenter position or collimator size, were determined so that the high dose region could be shaped to fit ideal models with the arrangement of multiple isocenter. Data base were formed with those results. Second, any shaped real targets were approximated to these models using geometry comparison. Then, optimum variables for ideal geometry were chosen from the data base predetermined, and final parameters were obtained by adjusting these data. Although the results of applying the data base to patients were not superior to the result of optimization in each case, it can be acceptable as a starting point of plan.

• BMB Reports
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• v.36 no.6
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• pp.552-557
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• 2003

Oligomers with $\alpha$-aminooxy acids are reported to form very stable turn and helix structures, and they are supposed to be useful peptidomimetics for drug design. A recent report suggested that homochiral oxa-peptides form a strong eight-member-ring structure by a hydrogen bond between adjacent aminooxy-acid residues in a $CDCl_3$ solution. In order to design an $\alpha$-MSH analog with a stable turn conformation, we synthesized four tetramers and one pentamer, based on $\alpha$-MSH sequence, and determined the solution structures of the molecules by two-dimensional NMR spectroscopy and simulated annealing calculations. The solution conformations of the three peptidomimetic molecules (TLV, TDV, and TLL) in DMSO-$d_6$ contain a stable 7-membered-ring structure that is similar to a $\gamma$-turn in normal peptides. Newly-designed tetramer TDF and pentamer PDF have a ball-type rigid structure that is induced by strong hydrogen bonds between adjacent amide protons and carbonyl oxygens. In conclusion, the aminooxy acids, easily prepared from natural or unnatural amino acids, can be employed to prepare peptidomimetic analogues with well-defined turn structures for pharmaceutical interest.

• Journal of the Korean Chemical Society
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• v.43 no.5
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• pp.540-546
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• 1999

Solution conformation of cyclo-($Gln^1-Trp^2-Phe^3-{\beta}Ala^4-Leu^5-Met^6$), new NK-2 antagonist in dimethyl sulfoxide solution, has been determined by the use of two-dimensional nuclear magnetic resonance spectroscopy combined with simulated annealing calculations. The peptide exhibited converged structures with the atomic root-mean-square difference for the backbone atoms ($N,\;C^{\alpha},\;C'$) of all residues being 0.02${\AA}$ in the 25 annealed structures. The analysis of the structures indicated that the cyclic peptide has three intramolecular hydrogen bonds between $Met^6NH$ and ${\beta}Ala^4CO$, ${\beta}Ala^4NH$ and $Met^6CO$, $Phe^3NH$ and $Met^6CO$, and contain a type-I ${\beta}$-turn with Gln and Trp and ${\gamma}$-turn with Leu. The addition of an extra methylene group to Gly, i.e. P-Ala residue, may relax some unfavorable restraints in the cyclic backbone structure, hence enabling an additional hydrogen bond, which results in stabilizing one conformation.

• Economic and Environmental Geology
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• v.32 no.2
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• pp.177-187
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• 1999

Gravity, magnetic and VLF surveys were conducted to investigat the structural stability and hazards associated with the Ubong landfill in Pohang City, which has been built to dump industrial wastes. In 1994, the collapse of a bank happened in the 6th landfill site due to sudden heavy rain, and a large quantity of waste materials flowed out to the nearby landfill sites, factories and roads. We used $10{\times}10m$ resolution DEM data for gravity reductions. The maximum variation of the terrain effect in the survey area is about 0.5 mgal and the terrain effect is large in the vicinity of bank boundary. The Bouguer gravity anomaly map shows the effect due to the variatino of thickness and type of waste materials. The small negative gravity anomaly increases from the 9th site to the 6th site. The small negative gravity anomaly of the 9th site reflects the relatively shallow dumping depth of average 14.5 m in this site and increased density of waste materials by the repeated stabilization process of soil overlaying. The 6th site is located at the center of the former valley and rainfall and groundwater are expected to flow from south-east to north-west. Therefore, considering the previous accident of mixing waste and bank materials at the north-west boundary of the landfill, there may be some environmental problems of leakage of contaminated water and bank stability. The complex inversion technique using Simulated annealing and Marquardt-Levenberg methods was applied to calculate three-dimensional density distribution from gravity data. In the case of 6th site, it is apparent that the landfill had been dumped in four sectors. However, most part of the 9th site and showed that high magnetic industrial wastes were concentrated in the 6th site. The result of magnetic survey showing low magnetic anomalies along the boundaries of two sites is similar to that of gravity data. The VLF data also reveals four divided sectors in the 6th site, and overall anomaly trend indicates the directio of former valley.

• Geophysics and Geophysical Exploration
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• v.12 no.1
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• pp.99-104
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• 2009

We propose a waveform inversion method for SH-wave data obtained in a shallow seismic refraction survey, to determine a 2D inhomogeneous S-wave profile of shallow soils. In this method, a 2.5D equation is used to simulate SH-wave propagation in 2D media. The equation is solved with the staggered grid finite-difference approximation to the 4th-order in space and 2nd-order in time, to compute a synthetic wave. The misfit, defined using differences between calculated and observed waveforms, is minimised with a hybrid heuristic search method. We parameterise a 2D subsurface structural model with blocks with different depth boundaries, and S-wave velocities in each block. Numerical experiments were conducted using synthetic SH-wave data with white noise for a model having a blind layer and irregular interfaces. We could reconstruct a structure including a blind layer with reasonable computation time from surface seismic refraction data.