• The Transactions of the Korean Institute of Electrical Engineers
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• v.45 no.4
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• pp.501-510
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• 1996

The gas-turbine generator of Seo-Incheon combined-cycle plant was tested for derivation of a model for dynamic analysis. Load rejection and AVR step test was performed to get the dynamic response of generator. The parameters of generator/control system model were determined by these measured data. No-load saturation test was performed for the saturation characteristics of the generator under steady state. V-curve test was also performed so as to find exact generator parameters. Q-axis parameters of generator was derived by measuring power angle. AVR and governor constants have been tuned by their oscillatory period and setting time characteristics. The derived parameters of generator control system is verified by one-machine infinite bus system simulation. (author). 7 refs., 20 figs., 5 tabs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.10
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• pp.1523-1531
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• 2017

In general, the thrust vector control should be fast and stable in the initial launch phase. Two types of conventional controllers, one is for pitch angle control and the other is for pitch rate control, are designed based on the equation of motion without aerodynamics and are compared in the viewpoints of the stability margin and the time response performance. Also analyzed are the rejection capabilities to cope with high aerodynamic disturbances caused by high angle of attacks in initial booting phase. Additionally, time response features at actuator saturation are investigated. Based on those results, we suggest a controller structure which is more suitable for thrust vector control of missiles at initial booting phase.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.500-500
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• 2000

In this paper, we deal wit,11 a simple tim varying feedforward compensator in order to decrease the amount of undershoots and overshoots on the step response. This compensator makes the step type input be a ramp input with saturation for 0 $\leq$ t < $\alpha$. It will be shown that the system with the feedforward compensator has small amount of undershoot and overshoot at the price of rise time. Also, provided the system properly stable, the influence of the design parameter $\alpha$ on the step response of the system with the feedforward compensator is investigated in the current paper.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.3
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• pp.156-165
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• 1997

In the practical control systems, the dynamic range of actuatiors is limited(or saturated) when actuators are driven by sufficiently large signals. This gives rise to a nonlinearity as a result of actuator saturation. For example, the upper limit is imposed on productive capability by available factory space and capital equipment. Other examples of those kinds of actuator saturations are a maximum torque of the actua- ting motors and a throttle position in an aircraft speed control A saturating actuator may lead not only to a large overshoot during start-up and shut-down, but also to deterioration of the performance due to the uncertainties. That is, the speed of response is decreased and, possibly, the system output may not follow the lalrge reference inputs. The large-overshoot may be accompanied by rest wind-up(or called by integra- tor wind-up) which comes from controllers with integral action in saturation operation regions. Eventually, as the overshoot increases, the system has a limit cycle or becomes oscillatorily unstable. Due to these cir- cumstances, many studies are focused on the stability and robustness of the nonlinear systems with satu- rating actuator in the time-domain as well as in the frequency-domain.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.360-363
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• 2009

In this paper, we describe new approach of ink particle fabrication method for electrophoretic display(EPD) with low voltage and rapid response time. Nano-size ink particles which fabricated using non-aqueous base modified emulsion process and micron-scale particles by non-solvent particle fabrication process are discussed. Finally, specially designed particles and panel structure fabricated considering the interactions between particle/particle, particle/media or particle/electrode dramatically reduce the driving voltages to ${\pm}$ 10V and improve the response time of less than 100msec and white reflectance of 58% for EPD using dielectric fluid as a medium. In case of EPD adapting micron-sized electrophoretic particles and a medium of air, the saturation voltage could be reduced to ${\pm}$ 40V and having white reflectance of 45% without scarification of electrophoretic mobility of the particles.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.333-336
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• 2001

The transient response in PDFA(Praseodymium-Doped Fiber Amplifier) is theoretically investigated. The PDFA has the spectral gain band in 1.3${\mu}{\textrm}{m}$. The transient model includes the transient buildup of the population inversion, the pump power, and the signal power and their transient variation along the fiber amplifier. The numerical analysis of transient model can predict the gain saturation, the variation of pump power and the gain as a function of the fiber length. It also shows the gain saturation and recovery effects depending on the pumping rate lead to distortion and saturation in the amplification of optical pulse. The results of numerical analysis, for the case of the Pr ion concentration of 1000ppm and the pump power of 0.5W the gain saturation is obtained 30dB at the length of 5m and the saturation time of upper level is 250 $mutextrm{s}$.

• Journal of Korean Critical Care Nursing
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• v.3 no.1
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• pp.41-51
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• 2010

Purpose: The purpose of this study was to identify the effects of family visits upon the stress response of patients and their families, Methods: This study was the interrupted time series design, The subjects consisted of 197 patients and 197 family members in the cardiac intensive care unit of S Hospital in Bucheon. Physiological stress responses such as blood pressure, heart rates, respiration rates, and oxygen saturation were measured using HP monitors. VAS was used to measure the emotional stress. Collected data was analyzed using repeated measure ANOVA, t-test by SPSS 17.0 statistical program. Results: The family visits did not change patients' blood pressure, pulse rate, respiration rate and oxygen saturation, However the anxiety level of patients and their family members were decreased significantly during family visits. Furthermore, 30-minute family visit reduced more effectively patient's anxiety than 15-minute family visit. Conclusion: Family visits need to be used as a means of nursing intervention to ease the emotional stress of patients and their families. In addition, increasing of visiting time should be considered.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.504-507
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• 2002

We investigated electro-optic and ionic properties of twisted nematic cells by using control of chiral pitch. These properties are observed in practical experiment and simulations. C-V and V-T curve characteristics were obtained from three types of cells with d/p. It is shown that d/p ratio of short cells exhibit faster response time improved by 20% than normal cell. Also, inter-gray response time is improved each rise time and decay time. And, the increase of saturation voltage is happened because of the small twist angel change from initial state at high voltage near 5V. To compensate for longer black level tail, gamma curve index was varied from g = 2.2 to g = 2.7 in module status. Additionally, adding chiral dopant into TN cells improved ionic characteristics such as increasing VHR, Ion density and DC Hysteresis were decreased..

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.1
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• pp.121-127
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• 2013

A vision based hand-gesture interface method for substituting a pointing device is proposed in this paper, which is used the ratio and size variation of Gesture Region. Proposed method uses the skin hue&saturation of the hand region from the HSI color model to extract the hand region effectively. This method can remove the non-hand region, and reduces the noise effect by the light source. Also, as the computation quantity is reduced by detecting not the static hand-shape recognition, but the ratio and size variation of hand-moving from the clipped hand region in real time, more response speed is guaranteed. In order to evaluate the performance of the our proposed method, after applying to the computerized self visual acuity testing system as a pointing device. As a result, the proposed method showed the average 86% gesture recognition ratio and 87% coordinate moving recognition ratio.

• Nuclear Engineering and Technology
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• v.50 no.3
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• pp.526-530
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• 2018

Human fingernails were used to estimate the radiation dose via electron paramagnetic resonance measurements of radiation-induced radicals. The limiting factors in this research were mechanically induced electron paramagnetic resonance signals due to the mechanical stress during the preparation of the samples. Therefore, different treatment methods of fingernails were used to reduce the mechanically induced signals. The results demonstrate that the mechanically induced and radiation-induced signals have apparently different microwave power saturation behaviors. In addition, the mechanically induced signal shows a fading evolution over time and reaches a constant value. Chemical treatment using the different reagents showed that the minimum mechanically induced signal was obtained using the dithiothreitol reagent. The dose-response curves of the samples treated with dithiothreitol for 30 minutes demonstrated a greater linearity than those of samples treated for 5 minutes. Therefore, to find an unknown absorbed dose in a fingernail sample using a calibration curve, we recommend adopting the mentioned chemical treatment procedure to reduce the uncertainty.