• The Transactions of the Korean Institute of Electrical Engineers P
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• v.64 no.1
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• pp.14-17
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• 2015

This paper presents a analysis method for power system stability using a Modified Genetic-based Power System Stabilizer(MGPSS). The proposed MGPSS parameters are optimized using Modified Genetic Algorithm(MGA) in order to maintain optimal operation of generator under the various operating conditions. To improve the convergence characteristics, real variable string is adopted. The results tested on a single machine infinite bus system verify that the proposed controller has better power system stability than conventional controller.

• Journal of Pharmaceutical Investigation
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• v.18 no.4
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• pp.181-186
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• 1988

Inclusion complex of sulfamethoxazole with ${\beta}-cyclodextrin$ was prepared by freeze-drying method in molar ratios of 1:1, 1:1.25, 1:1.5 and 1:1.75, and the complex formation was identified by ultraviolet and infrared spectroscopies, powder X-ray diffractometry and differential scanning calorimetry. Dissolution rate and solid state stability of the complex were investigated in comparison with those of sulfamethoxazole powder and the physical mixture of sulfamethoxazole with ${\beta}-cyclodextrin$. As a result, the dissolution rate and the stability of solid complexes in various relative humidity conditions increased more remarkably than those of sulfamethoxazole powder and physical mixture. But the difference according to molar ratio of the complex was not recognized.

• Journal of Industrial Technology
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• v.24 no.A
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• pp.215-226
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• 2004

A dynamic reliability model which can take into account the time history of loading sequences may be applied to the analyses of the hydraulic stability of armor units on rubble-mound breakwaters. All the parameters related to the stability of structures have been considered to be constants in the deterministic model until now. Thus, it is impossible to study the effects of some uncertainties of the related random variables on the stability of structures. In this paper, the dynamic reliability model can be developed by POT(Peak Over Threshold) method in order to take into account the time history of loading sequences and to investigate the temporal behaviors of stability of structure with its loading history. Finally, it is confirmed that the results of dynamic reliability model agree with straight- forwardly those of AFDA(Approximate Full Distribution Approach) of the static reliability model for the same input conditions. In addition, the temporal behaviors of probability of failure can be studied by the dynamic reliability model developed to analyze the hydraulic stability of armor units on rubble-mound breakwaters. Therefore, the present results may be useful for the management of repair and maintenance over the whole life cycle of structure.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.8
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• pp.80-85
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• 2021

This study is to evaluate the structural stability of heavy duty structure of the Complex CNC automatic lathe. The analysis conditions were analyzed by applying the weight and load of the part itself and then applying the weight of the upper assembly unit. As a result of the structural analysis, the values of stress and strain are small and safety factor is high, and as a result of the dynamic analysis, there will be no resonance outside the equipment driving area, so there will be no problem in equipment stability.

• Food Science and Biotechnology
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• v.18 no.5
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• pp.1230-1236
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• 2009

Optimum conditions for the freeze-thaw stability (FTS) of mung bean starch (MBS) paste as a main ingredient in omija-eui were investigated. For the optimization of the paste preparation condition, the FTS of MBS prepared by boiling in a shaking water bath (BMSW) or by pressure-cooking in an autoclave (PCMA) were analyzed using a response surface methodology (RSM). In addition, the effects of various additives such as gums, sugars, and emulsifier were evaluated on the FTS of MBS paste prepared under optimal conditions. The predicted maximal FTS of MBS paste prepared by the PCMA method (73%) was higher than that of the paste prepared by the BMSW method (36%). In case of additives, gellan gum and sodium alginate effectively prevented the syneresis of MBS paste in the BMSW method and in the PCMA method, respectively. The use of a fructose fatty acid ester as an emulsifier decreased syneresis in a dose-dependent, while the addition of sugars accelerated syneresis. Consequently, MBS paste for omija-eui preparation may be efficiently prepared by adding sodium alginate and fructose fatty acid ester under the optimal conditions of 4.3% MBS content, $121^{\circ}C$ heating temperature, and $89^{\circ}C$ cooling temperature by pressure-cooking in an autoclave.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.3
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• pp.59-71
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• 2015

Purpose : This study examines the effect of vibration exercise grafting PNF patterns for 6 weeks on upper body stability and equilibrium for seniors having fifteen or over of MMSE-K. Method : A total of 10 senior citizens participated in this study. Each participant performed PNF patterned exercises using vibration sports equipment for 30 minutes, once static a week, for six weeks. We measured trunk stability and balance degree before and after the six-week exercise program. Motor Assessment Scale (MAS) was used to measure trunk stability, while Functional Reach Test (FRT) and Timed Up and Go (TUG) was used to measure balance degree. The collected data was processed using paired t-test to confirm the difference between pre-program conditions and post-program conditions. Results: The results of our study show that post-program trunk stability measurements increased when compared to pre-program data; however, this increase was not statistically significant. pre and post-measurements for satatic balance and dynamic balance were statistically unchanged. Conclusion: Due to limitations in the number of participants, the procedural design of this experiment, and the limited amount of time participants actually controlled, this study failed to produce statistically significant results. However, further study should be conducted using a systematically implemented exercise program to show support for exercising with flexi-bar as an effective program for the elderly.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2005.03a
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• pp.74-81
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• 2005

The purpose of this study is to suggest a proper analysis model that can evaluate seismic stability for local rock foundation of nuclear power plant. Sliding Analysis, Pseudo-static Analysis and Danamic Analysis methods are used for analysing NPP rock foundation with the conditions like acting directions of input earthquake, boundary conditions, width and depth of analysing model, and modeling methods of weakness fault zones. As the results of study, Pseudo-static Analysis for lateral roller and dynamic analysis for transfer boundary condition showed good results, and analysing ranges of width and depth were 5 times of structure width and over 2 times of structure depth.

• The Journal of Korean Physical Therapy
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• v.24 no.3
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• pp.181-185
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• 2012

Purpose: We investigated balance change in patients with low back pain (LBP) by comparing postural sway velocity between young LBP patients and healthy subjects. Methods: The cross-sectional study enrolled 37 young patients with over 3-month duration of LBP and 38 healthy subjects between the ages of 20 and 30 years old. All subjects were targeted by measuring their balance during quiet standing with open eye and closed eye conditions. The postural sway velocity between the LBP patients and healthy subjects was compared. As well, postural sway velocity was determined in the LBP patients with both eyes open and closed. Results: Significant differences were evident in the anteroposterior and mediolateral mean velocity of center-of-pressure between LBP patients and healthy subjects, and in LBP patients in the eye open and eye closed conditions. Conclusion: The balance of young LBP patients was worse than healthy subjects during quiet standing, and was especially lessened in the absence of vision.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.40-43
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• 2008

High temperature polymer electrolyte membranes incorporating ionic liquids (ILs) in different polymers such as commercial fluorinated polymers, sulfonated polymers and recasted nafion have been developed. ILs based on imidazolium cation and different anions possess high ionic conductivity and good thermal stability and have been used in the present study. The membranes containing IL show conductivity ${\sim}10^{-2}S\;cm^{-1}$ above $100^{\circ}C$ under anhydrous conditions and are thermally stable up to $250-300^{\circ}C$. IL acts as a conducting medium in these electrolytes and plays the same role as played by water in fully hydrated nafion membranes. Due to high conductivity and good thermal stability, these membranes are promising materials for PEFCs at higher temperatures under anhydrous conditions.

• Journal of the Semiconductor & Display Technology
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• v.16 no.2
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• pp.15-18
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• 2017

In this study, we have studied the characteristics of the organic photodiode varying due to the blending conditions of the quantum dots (QDs). The active layer of the photodiode was formed with poly (3-hexylthiophene) and phenyl-C61-butyric acid methyl ester, and CdSe QDs with and without ZnS shell were blended in the active layer. The photodiode with CdSe/ZnS QDs showed the highest power conversion efficiency (PCE) and short-circuit current (Jsc). The performance change of the organic photodiode by X-ray irradiation was also measured. Regardless of X-ray irradiation conditions, the photodiode with CdSe/ZnS QDs showed better stability than other cases.