• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1372-1377
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• 2003

The stabilization of propane/air lean premixed flames by a heated cylindrical rod is investigated experimentally. The flame stability limits, heat flux, surface temperatures, equivalence ratios, and mixture velocities are measured in order to understand the role of heat flux or surface temperature on the flame stabilization of lean premixed flames. The flame stability limits are lowered by a heated cylindrical rod and extended even below the flammability limit of propane/air mixture when sufficient heat flux is provided. The flame stability limit decreases with the increase of heat flux or surface temperature and decreases with the higher mixture velocity. The diameter of cylindrical rod, however, dose not significantly affect the flame stability limit. The laminar flame speed has been measured for ultra lean propane/air premixed flames. The flame stabilization by a heated cylindrical rod provides the useful tool for the measurement of flame speed under very fuel-lean conditions.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.259-262
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• 2002

Application of combustion stabilization devices such as baffle and acoustic cavity to liquid propellant rocket engine is investigated to suppress high-frequency combustion instability, i.e., acoustic instability. First, these damping devices are designed based on linear damping theory. As a principal design parameter, damping factor is considered and calculated numerically in the chambers with various specifications of these devices. Next, the unbaffled chambers with/without acoustic cavities are tested experimentally for several operating conditions. The unbaffled chamber shows the specific stability characteristics depending on the operating condition and has small dynamic stability margin. The most hazardous frequency is clearly identified through Fast Fourier Transform. As a result, the acoustic cavity with the present design has little stabilization effect in this specific chamber. Finally, stability rating tests are conducted with the baffled chamber, where evident combustion stabilization is observed, which indicates sufficient damping effect. Thrust loss caused by baffle installation is about $2{\%}$.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.5
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• pp.494-501
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• 1999

In this research, ANN modeling method of SMES unit is developed for stability analysis, and the optimal site is selected to maximize stabilization effect of SMES unit. The ANN is trained by learning data which is obtained through the application of complex test function into the traditional mathematical mode. In order to verify the validity of proposed modeling method, fault data of sample power system is applied to both the traditional and the ANN models. When the response of traditional and proposed models are compared, the average error for the active and reactive power are 2.51[%], and 0.24[%], respectively. From the comparison, the relevance of proposed method is validated. For the transient stability analysis, an application method of the proposed model is presented, and the transient stability performance index, which describes system stabilization effect of SMES at disturbance, is also suggested, and optimal site selection method of SMES is presented. In the viewpoint of the voltage stability, system stabilization criterion of local bus is presented from P­V curve, and then optimal site which can maximize the voltage stabilization of the whole power system, is decided from the proposed voltage stability performance index.

• The Journal of Korean Physical Therapy
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• v.28 no.4
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• pp.221-226
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• 2016

Purpose: This study was conducted to evaluate the effects of neck and trunk stabilization exercise on static and dynamic balance in older adults. Methods: A total of 30 older adults participated in this study. Participants were randomly assigned to the neck and trunk stabilization exercise group (NTSG) (n=15) or the trunk stabilization exercise group (TSG) (n=15). The NTSG performed a trunk stabilization exercise added to a neck stabilization exercise that included biofeedback. Both groups received training for 30 minutes per day three times per week for eight weeks. The anterior, posterior limit of stability and sway length was used to measure static balance ability, while the timed up and go (TUG) test was used to measure dynamic balance ability. Results: Participants showed significant differences in sway length, anterior limit of stability, posterior limit of stability, and the results of the TUG test between their pre- and post mediation evaluations (p<0.05). The NTSG showed a more significant increase than the TSG (p<0.05). Conclusion: According to the results of this study, both exercises effectively improved static and dynamic balance ability. However, the neck and trunk stabilization exercise is more efficient for increasing the balance ability of older adults.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.32-34
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• 1998

Phytase from Aspergillus species is a very heat unstable enzyme which inactivates to a great extent during the thermal processing of animal feed formulation. Various protein stabilization additives were tested to improve its heat stability. Among them, a basic amino acid, L-arginine remarkably increased the thermal stability of phytase in an aqueous solution state.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.1
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• pp.127-136
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• 2017

This paper investigates improved stability and stabilization criteria for sampled-data control systems. By using a suitable and newly constructed augmented Lyapunov-Krasovskii functional and some recent mathematic techniques such as auxiliary function-based integral inequalities, sufficient conditions for stability and stabilization conditions are derived within the framework of linear matrix inequalities(LMI) form. The superiority and validity of the proposed results are illustrated by three numerical examples.

• Physical Therapy Korea
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• v.23 no.4
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• pp.38-46
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• 2016

Background: Shoulder stabilization commonly involves two components: the glenohumeral stabilization exercise (GSE) and scapular stabilization exercise (SSE). Despite the fact that the shoulder stabilization has advantageous merit, to our knowledge, only a few studies have compared the superior of the GSE and the SSE. Objects: The purpose of this study was to assess the effects of GSE in patients with nonspecific shoulder pain. Methods: Thirty subjects with nonspecific shoulder pain were randomly divided into an experimental group and control group, each with 15 patients. The experimental group used an GSE, whereas the control group did SSE. All subjects were measured in shoulder stability, scapular symmetric alignment, pain, muscle power, and range of motion before and after the intervention. Results: GSE resulted in significantly better shoulder stability (p=.046, from $8.67{\pm}7.54$ score to $13.93{\pm}9.40$) in the experimental group compared with SSE in the control group. However, no significant effects were observed for scapular symmetric alignment including the angles of inferior scapular distance (p=.829) and inferior scapular height difference (p=.735), pain (p=.113), muscle power including shoulder flexion (p=.723) and abduction (p=.897) and range of motion including shoulder flexion (p=.853) and abduction (p=.472). Conclusion: These findings suggest that GSE may be more effective in increasing the shoulder stability than the SSE in patients with nonspecific shoulder pain, probably through a centralization effect on the shoulder mechanism.

• PNF and Movement
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• v.12 no.2
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• pp.63-69
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• 2014

Purpose: The purpose of this study was to investigate the effect that trunk stability exercises with stabilizing reversal and rhythmic stabilization of PNF have on trunk strength and balance ability in stroke patients. Methods: This study included 20 stroke patients who performed trunk stability exercises combined with stabilizing reversal and rhythmic stabilization of PNF. The exercise program consisted of 30-minute sessions per week for six weeks. Trunk strength (BTE, Primus RS) and balance ability (Berg Balance Scale) were evaluated before and after training. All data were analyzed using SPSS 18.0 software. Results: Significant differences were observed the both groups for truck strength and balance ability. The results of the study were as follows: trunk strength was significantly increased in both groups (p<.05) and it was also found to be significant between groups after the intervention (p<.05). Balance ability was significantly increased in both groups (p<.05) and it was also found to be significant between the groups after intervention (p<.05). Conclusion: Trunk stability exercises with stabilizing reversal and rhythmic stabilization of PNF are effective for improving trunk strength and balance ability in stroke patients. For stroke patients, trunk stability exercises with PNF are very useful and effective and they areeffectiveinclinicalpractice.

• Journal of applied mathematics & informatics
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• v.11 no.1_2
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• pp.81-108
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• 2003

We consider the Korteweg-de Vries-Burgers (KdVB) equation on the domain [0,11]. We derive a control law which guarantees $L^2$-global exponential stability, $H^3$-global asymptotic stability, and $H^3$-semiglobal exponential stability.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.12
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• pp.3344-3351
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• 1995

The stability of diffusion flame formed behind a bluff body with fuel injection slits was experimentally investigated in various fuel injection angles, fuel injection ratios, grids and extension ducts. The flame stability limits, temperature distributions and length of recirculation zones, direct photographs of flames were measured in order to discuss the stabilization mechanism of the diffusion flame. The results from this study are as follows. The fuel injection angle is an important factor in determining the flame stability. Stability limits can be improved by variety of the fuel injection ratio. When the grid and extension duct are set, stability characteristics are varied with the blockage ratios, grid intervals, and grid numbers. The recirculation zone not only serves as a steady ignition source of combustion stream but also governs the stabilization mechanism.