• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4008-4014
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• 2011

The purpose of this study was to identify the effect of muscular strength, sensation, and spasticity of the hip joint on balance using clinical tools in chronic stroke patients. Thirty-two subjects participated. It were measured muscular strength of the hip flexor, extensor, abductor, and adductor using manual muscle testing, light touch sensibility, and spasticity of the quadriceps using the modified Ashworth scale in the paretic lower extremity. Also, static and dynamic balance were measured by the functional balance scale. Collected data was analyzed by stepwise multiple regression. Muscular strength of the hip abductor, light touch sensibility, and spasticity were associated with static balance(p<0.05) and explanatory power was 80.5%. Muscular strength of the hip abductor and light touch sensibility were associated with dynamic balance(p<0.05) and explanatory power was 77.9%. Thus, it is suggested that muscular strength of the hip abductor and light touch sensibility is considered when providing evaluation and intervention programs for the future in the balance.

• Korean Journal of Metals and Materials
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• v.46 no.2
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• pp.65-68
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• 2008

Generally CCM (cold crucible melting) is not suitable for melting glass. However, in this study we described the quantitative relationship between the basic property of glass and power balance, the power absorption in the melt, the losses in the coil and the cold crucible, for melting glass in CCM. The dependence of power balance on the applied frequency and the electric conductivity has been found. Above 300 kHz, the glass (B) contained alkali ion which has the low resistance $3.0{\Omega}{\cdot}cm$ at $900^{\circ}C$ and $1.36{\Omega}{\cdot}cm$ at $1,100^{\circ}C$ was melted easily and 60% of the overall power was absorbed in the melt and 30% and 10% of the overall power was lost in the cold crucible and coil respectively. Under the same condition, the glass (A) contained non-alkali ion was not melted easily and 50% of the overall power was absorbed in the melt and 40% and 10% of the overall power was lost in the cold crucible and coil respectively. In conclusion, the small absorbed power of the overall power in melt prevented a successful melting as for glass A, and the successful melting depends on the relative size of the absorbed power in melt irrespective of the melting volume. Hence, as typical for direct induction heating method(CCM), the successful melting strongly depended on the chosen working frequency based on electric conductivity of glass, power balance and the control of the critical power which was absorbed in melt.

• Journal of Korean Physical Therapy Science
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• v.27 no.1
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• pp.56-65
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• 2020

Purpose: Individuals affected by stroke present with changes in motor function, balance, and cognition. The purpose of this study was to the correlation between motor function, balance, and cognition in patients with stroke. Design: cross-sectional study design. Methods: 67 stroke patients in the experiment were included. For evaluation of motor function which is Manual Muscle Test, Range of Motion, Modified Ashworth Scale for spasticity, grasping power, and balance was measured using the Berg Balance Scale and Functional reach test. For evaluating Cognition which is Korean-Mini Mental State Examination. Results: The results of this study's motor function, balance, and cognition showed a significant positive correlation (p<0.05). Conclusion: The results indicated that motor function, balance, and cognition were significantly correlated with each other. Therefore, it is suggested that to improve the motor function and balance of patients with stoke, it needs to evaluate the cognition and the motor function, balance, and cognitive training should be combined.

• Journal of Power Electronics
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• v.19 no.2
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• pp.487-496
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• 2019

For a solid-state transformer (SST), some factors, such as signal delay, switching loss and differences in the system parameters, lead to unbalanced DC-link voltages among the cascaded H-bridges (CHB). With a control method implemented in the ${\alpha}{\beta}$ frame, the DC-link voltages are balanced, and the reactive power is equally distributed among all of the H-bridges. Based on the ${\alpha}{\beta}$ frame control, the system can achieve independent active current and reactive current control. In addition, the control method of the high-voltage stage is easy to implement without decoupling or a phase-locked loop. Furthermore, the method can eliminate additional current delays during transients and get the dynamic response rapidly without an imaginary current component. In order to carry out the controller design, the vector refactoring relations that are used to balance DC-link voltages are derived. Different strategies are discussed and simulated under the unbalanced load condition. Finally, a three-cell CHB rectifier is constructed to conduct further research, and the steady and transient experimental results verify the effectiveness and correctness of the proposed method.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.1
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• pp.34-41
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• 1999

A three-level ZCT(Zero Current Transition) IGBT inverter is presented for high power IGBT inverters. The concept of ZCT for the conventional boost converter is extended to the three-level inverter. Moreover, in order to improve the reliability of inverter, midpoint charge balance problem of the three-level inverter is analyzed with respect 150kw, 20kHz prototype are presented to verify the principle of ZCT Operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2012-2015
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• 2010

In this paper, the mathematical models of the superheater and the desuperheater are derived based on the fundamental laws of physics, mass and energy balance. The parameters of the models are developed for the 500[MW] thermal power plant using the actual data. The simulated model outputs are well matched with the actual ones. It is expected that the proposed models are useful for the temperature controller design of the thermal power plant.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.11 no.8
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• pp.303-313
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• 2001

The identification of power flow in dynamically loaded structures Is essential in the analysis of structure-borne noise. However there are no general purpose tools to estimate powers flow. To make matters worse. It is very difficult to measure it. The power flow can be formulated in terms of balance forces(ELFORCE) at each element and velocities at the associated node obtained with MSC/NASTHAN. In this paper the procedure which is consist of the computations of the balance forces of al1 elements and the velocities at all nodes using MSC/NASTRAN. The calculations of the power f1ow at each element using PCL(PATRAN Command Language) and the Preparation of post -processes is set UP.

• Journal of Power Electronics
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• v.9 no.5
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• pp.700-707
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• 2009

The coal mill used in the coal-fired power plants is modeled in view of the controller design rather than the educational simulator. The coal mass flow and the outlet temperature are modeled by reinvestigating the mass balance and heat balance models physically. The archived data from a plant database are utilized to identify the model parameters. It can be seen that the simulated model outputs are well matched with the measured ones. It is also expected that the proposed model is useful for the controller design.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.3-6
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• 2004

Power semiconductor devices are being compact, high performance and intelligent thanks to recent remarkable developments of silicon design, process and related packaging technologies. Developments of MOS-gate transistors such as MOSFET and IGBT are dominant thanks to their advantages on high speed operation. In conjunction with package technology, silicon technologies such as trench, charge balance and NPT will support future power semiconductors. In addition, wide band gap material such as SiC and GaN are being studies for next generation power semiconductor devices.

• Proceedings of the IEEK Conference
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• 2001.06a
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• pp.185-188
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• 2001

In this paper, we design and implement high-power amplifier with 18 watt for W-CDMA repeater. We simulate microwave circuits using RF simulator, ADS1.3 and optimize the circuit to obtain the linear and high power using Harmonic balance method. Harmonic balance is an excellent method in the analysis of nonlinear system. The HPA is fabricated on tefron substrate($\varepsilon_{{\gamma}}$=3.48, h=0.5mm, T=0.035mm). From the measured result, the HPA has gain of 52dB, 1 dB compression power of 52.8dBm and good ACPR (Adjacent Channel Power Radio) performance.l Power Radio) performance.