• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.693-695
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• 2004

Among modem control method, the observer is being used widely because it has the advantage of the guarantee of reliability on financial problem, over heating, and physical shock. However, an existing state observer and a sliding observer have such problems that an experimenter needs to know dynamics and parameters of the system. And also, the high gain observer has such a problem that it has transient state at the beginning of the observation. In this paper, the neuro observer is proposed to improve these problems. The proposed observer complement a problem that occur from increase of gain of High-gain observer in proportion to the square number of observable state variables. And also, the proposed observer can tune the gain obtained by differentiating observational error at transient state automatically by using the backpropagation training method to stabilize the observational speed. To prove a performance of the proposed observer, it is simulated that the comparison between the state estimate performance of the proposed observer and that of sliding, high gain observer is made by using a sinusoidal input to the observer which consists of four layers in stable 2nd order system.

• Journal of Nutrition and Health
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• v.32 no.5
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• pp.533-539
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• 1999

The effects of capsaicin, a pungent principle of hot red pepper, on body fat gain, balance serum lipid values were investigated in rats fed a high-fat(30%) diet. Administration of capsaicin by dietary administration caused a complete cessation of increased in body weight and fat gain induced by the high-fat diet. However, energy intake and body protein gain were not affected by capsaicin. Therefore, the suppression of body fat gain by capsaicn was believed due to an increased in energy expenditure. Simultaneous administration of capsaicin and a $\beta$-adrenergic blocker, propranolo, resulted in the inhibition of changes in body fat gain by capsaicin without remained unchanged, indicating an increase in the number of mitochondria in brown adipose tissue. Therefore, it appears that capsaicin possesses potent body fat suppressive effects mediated by $\beta$-adrenergic stimulation in which brown adipose tissue may be involved. On the other hand, capsaicin had no effects on serum triglyceride, total cholesterol or HDL-cholesterol levels. These results are in contrast to those reported by other investigators. Perhaps expression of the effects of capsaicin on plasma lipids is a rather complicated process, dependent on the type of diet administered, fat content of the diet, period and route of capsaicin administration, and species and strain of animals used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.3
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• pp.485-491
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• 2003

In this paper, We designed the multi-stage amplifier having high gain/low noise characteristics for terrestial repeater of direct digital satellite broadcasting system. In the design the amplifier, we optimized the parameters to have the stable operation between gain, noise figure and stability. The first stage of amplifier can be specified low noise impedance matching, 2nd stage to 5th stage show constant gain and stable operation and final stage of amplifier shows high gain impedance matching. As a result of experiment at the frequency of digital satellite terrestial, show 68dB gain under 2,4dB noise figure and 63dB dynamic range in the 11.7GHz-12.7GHz frequency range, it is a good agreement of communication channel amplifier requirements for satellite terrestial repeater.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.2
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• pp.221-226
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• 2012

In this paper, wideband two-stage amplification stage was designed, fabricated and evaluated. The proposed amplification stage with a novel gain control method have a high gain, low noise and high linearity performance. It is consisted of common emitter amplifier as the first stage, cascode gain control amplifier as second stage and power detector which sense the received signal strength. The proposed amplification stage shows a total gain of 29 dB~37 dB, noise fiugre of 1.5 dB at operating band and high linearity performance as the IMD (third intermodulation distortion) level is below the noise level of the measurement equipment at the control voltage 2.0 V generated from power detector under the strong electric field condition.

• Journal of electromagnetic engineering and science
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• v.11 no.1
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• pp.27-33
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• 2011

In this paper, we propose a high gain, current reused ultra wideband (UWB) low noise amplifier (LNA) that uses TSMC 0.18 ${\mu}m$ CMOS technology. To satisfy the wide input matching and high voltage gain requirements with low power consumption, a resistive current reused technique is utilized in the first stage. A ${\pi}$-type LC network is adopted in the second stage to achieve sufficient gain over the entire frequency band. The proposed UWB LNA has a voltage gain of 12.9~18.1 dB and a noise figure (NF) of 4.05~6.21 dB over the frequency band of interest (1~10 GHz). The total power consumption of the proposed UWB LNA is 10.1 mW from a 1.4 V supply voltage, and the chip area is $0.95{\times}0.9$ mm.

• Journal of Broadcast Engineering
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• v.23 no.6
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• pp.925-930
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• 2018

In this paper, we present a low profile dual-microstripline-fed double 4-arrayed meander monopole antenna with a cross-type element back by separated four-segments mesh-type reflector. The cross-type element and separated four-segments mesh-type reflector leads to enhance radiation patterns and antenna gain characteristics. The measurement value of the proposed antenna show that it has dipole-like radiation pattern characteristics. The experimental peak gain of fabricated antenna is about 2.89 dBi, which presents relatively high gain characteristics for a low profile(small-size) one. This antenna can be applied mobile RFID(radio frequency identification) readers, small medical instruments, broadcasting and home-networking operations, and other low profile high-gain systems.

• Korean Journal of Community Nutrition
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• v.2 no.2
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• pp.169-178
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• 1997

Thin study measured dietary intakes in late pregnancy and psychological stress during the period of gestation and examined the roles of diet and psychological stress in pregnancy weight gain and infant birth weight. Study subjects were 98 pregnant women who delivered infants at 2 general hospitals in Taejon city. Mean weight gain during pregnancy was 14.6$\pm$4.89Kg. Mean infant birth weight was 3.39$\pm$0.62kg in males and 3.28$\pm$0.43Kg in females. Mean energy and protein intake levels were adequate, but mean iron and calcium intakes were only 61.2$\pm$14.9% and 79.1$\pm$18.2$\%$ of RDA, respectively. Fat intake which constitutes 22.0$\pm$4.3$\%$ of total energy intake, and animal protein intake which constitutes 22.0$\pm$4.3$\%$ of total energy intake, and animal protein intake which constitutes 53.7$\%$ of total protein intake were moderately high. Though mean energy, fat, animal protein, and meat protein intakes in the low psychological stress group were higher than those in the middle or high stress group, psychological stress did not significantly affect pregnancy weight gain and infant birth weight. High intakes of nutrients except for dairy protein, iron, and niacin were associated with higher pregnancy weight gain and high intakes of protein and meat protein were associated with higher infant birth weight. It is concluded that dietary intakes during pregnancy has effects on pregnancy weight gain and infant birth weight, and psychological stress has no direct effect on them.

• The KIPS Transactions:PartA
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• v.12A no.6 s.96
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• pp.531-538
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• 2005

In the high performance Analog Information Processing Systems(AIPS), gain boosting or additional gain stage is required when the gain is not sufficient with one stage amplification. This work shows that high gain is neatly obtained by enhancing the gain using the negative resistance element. Compared to the conventional techniques, the proposed scheme enjoys full output swing, small circuit area and power consumption, and the applications to various configurations of amplifiers. The negative resistance element is placed between the differential output nodes when used in the Op-Amp. The HSPICE simulation indicates that enhancement of more than 40 dB is readily obtained in this simple configuration when the negative resistance element is implemented in the form of cross-coupled CMOS inverters.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.4
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• pp.533-538
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• 2016

In a power grid that has a high penetration of wind power, the highly-fluctuating output power of wind turbine generators (WTGs) adversely impacts the power quality in terms of the system frequency. This paper proposes a power smoothing scheme of a variable-speed WTG that can smooth its fluctuating output power caused by varying wind speeds, thereby improving system frequency regulation. To achieve this, an additional loop relying on the frequency deviation that operates in association with the maximum power point tracking control loop, is proposed; its control gain is modified with the rotor speed. For a low rotor speed, to ensure the stable operation of a WTG, the gain is set to be proportional to the square of the rotor speed. For a high rotor speed, to improve the power smoothing capability, the control gain is set to be proportional to the cube of the rotor speed. The performance of the proposed scheme is investigated under varying wind speeds for the IEEE 14-bus system using an EMTP-RV simulator. The simulation results indicate that the proposed scheme can mitigate the output power fluctuation of WTGs caused by varying wind speeds by adjusting the control gain depending on the rotor speed, thereby supporting system frequency regulation.

• The Journal of Korea Robotics Society
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• v.17 no.2
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• pp.221-229
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• 2022

Sliding mode control (SMC) is a robust control method to control a robot arm with nonlinear properties. A high switching gain of SMC causes chattering problems, although the SMC allows the adequate control performance by giving high switching gain, without the exact robot model containing nonlinear and uncertainty terms. In order to solve this problem, SMC with sliding perturbation observer (SMCSPO) has been researched, where the method can reduce the chattering by compensating the perturbation, which is estimated by the observer, and then choosing a lower switching control gain of SMC. However, optimal gain tuning is necessary to get a better tracking performance and reducing a chattering. This paper proposes a method that the Q-learning automatically tunes the control gains of SMCSPO with an iterative operation. In this tuning method, the rewards of reinforcement learning (RL) are set minus tracking errors of states, and the action of RL is a change of control gain to maximize rewards whenever the iteration number of movements increases. The simple motion test for a 7-DOF robot arm was simulated in MATLAB program to prove this RL tuning algorithm. The simulation showed that this method can automatically tune the control gains for SMCSPO.