• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.9
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• pp.1793-1801
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• 1994

In this paper, a new method for predicting the 1 dB gain compression point of cascaded N amplifiers is proposed. With the proposed method, the transfer function of each amplifier is derived from scalar data available from the manufacturers data sheet and all transfer functions are producted with scalar in order to also derive the overall transfer function of the subsystem under the assumption that the input and output port of each amplifier are matched. Therefore, the 1 dB gain compression point of the subsystem can be predicted or estimated, reversely, utilizing the overall transfer function obtained with the proposed method. The proposed method can be used irrespective of the number of scalar data but, in this paper, it is analyzed only with two scalar data (linear power gain and 1 dB gain compression point) and three scalar data(linear power gain, 1 dB and 0.5 dB gain compression points). With two sample amplifiers operated in Ku-band, the predicted results by the proposed and previous method, respectively, and the experimental results are together presented in order to confirm its utility.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2001.06a
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• pp.101-104
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• 2001

In this paper, we propose the Digital Automatic Gain Controller for IEEE 802.11a High-speed Physical Layer in the 5 GHz Band. The input gain is estimated by calculating the energy of the training symbol that is a synchronizing signal. The renewal gain is calculated by comparing the estimated gain with the ideal gain. The renewal gain is converted into the controlled voltage for GCA to reduce or amplify the input signals. We used a piecewise-linear approximation to reduce the hardware size. The gain control is performed seven times to provide more accurate gain control. The proposed automatic gain controller is designed with VHDL and verified by using the Xilinx FPGA.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.1-7
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• 2009

The Geostationary Ocean Color Imager (GOCI) is under development to provide a monitoring of ocean-color around the Korean Peninsula from geostationary platforms. It is planned to be loaded on Communication, Ocean, and Meteorological Satellite (COMS) of Korea. In this study, the radiometric model of GOCI, which is constructed based on the functional model of sub-system, is introduced. Non-linearity for each channel is analyzed in terms of linear gain and nonlinear gain by using the radiometric model. The non-linearity characteristic is validated by using test data which have been achieved during ground test at payload level. The non-linearity $G^3$/b shows identical characteristic for all channels.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.762-767
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• 2008

This paper introduces a $L_{\infty}$-gain state feedback fuzzy controller design for the time delay nonlinear system represented by Takagi-Sugeno(T-S) fuzzy model. First, the T-S fuzzy model is employed to represent the time delay nonlinear system. Next based on the fuzzy model, a fuzzy state feedback controller is developed to achieve $L_{\infty}$-gain performance. Finally, sufficient conditions are derived for $L_{\infty}$-gain performance. The sufficient conditions are formulated in the format of linear matrix inequalities (LMIs). The effectiveness of the proposed controller design methonology is finally demonstrated through numerical simulations.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.8
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• pp.1172-1180
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• 2013

Two experiments were conducted to determine the standardized ileal digestible (SID) lysine (Lys) requirement and the ideal SID threonine (Thr) to Lys ratio for finishing barrows. In Exp. 1, 120 barrows with an average body weight of $72.8{\pm}3.6$ kg were allotted to one of six dietary treatments in a randomized complete block design conducted for 35 d. Each diet was fed to five pens of pigs containing four barrows. A normal crude protein (CP) diet providing 15.3% CP and 0.71% SID Lys and five low CP diets providing 12% CP with SID Lys concentrations of 0.51, 0.61, 0.71, 0.81 and 0.91% were formulated. Increasing the SID Lys content of the diet resulted in an increase in weight gain (linear effect p = 0.04 and quadratic effect p = 0.08) and an improvement in feed conversion ratio (FCR) (linear effect p = 0.02 and quadratic effect p = 0.02). For weight gain and FCR, the estimated SID Lys requirement of finishing barrows were 0.71 and 0.71% (linear broken-line analysis), 0.79 and 0.78% (quadratic analysis), respectively. Exp. 2 was a 26 d dose-response study using SID Thr to Lys ratios of 0.56, 0.61, 0.67, 0.72 and 0.77. A total of 138 barrows weighing $72.5{\pm}4.4$ kg were randomly allotted to receive one of the five diets. All diets were formulated to contain 0.61% SID Lys (10.5% CP), which is slightly lower than the pig's requirement. Weight gain was quadratically (p = 0.03) affected by SID Thr to Lys ratio while FCR was linearly improved (p = 0.02). The SID Thr to Lys ratios for maximal weight gain and minimal FCR and serum urea nitrogen (SUN) were 0.67, 0.71 and 0.64 using a linear broken-line model and 0.68, 0.78 and 0.70 using a quadratic model, respectively. Based on the estimates obtained from the broken-line and quadratic analysis, we concluded that the dietary SID Lys requirement for both maximum weight gain and minimum FCR was 0.75%, and an optimum SID Thr to Lys ratio was 0.68 to maximize weight gain, 0.75 to optimize FCR and 0.67 to minimize SUN for finishing barrows.

• Animal Bioscience
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• v.34 no.3_spc
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• pp.427-433
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• 2021

Objective: An experiment was conducted to investigate the effects of Achyranthes japonica extracts (AJE) on the growth performance, nutrient digestibility, fecal microbial shedding, and fecal gas emission of growing pigs. Methods: A total of 180 ([Landrace×Yorkshire]×Duroc) growing pigs with initial body weight (BW) of 23.94±1.54 kg were used in this study to investigate the effects of AJE as a feed additive. Dietary treatments included: i) CON (basal diet), ii) TRT1 (basal diet+0.05% AJE), and iii) TRT2 (basal diet+0.10% AJE). Results: As a result of the dietary supplementation of 0% to 0.10% AJE, a linear increase of BW (p<0.05) on d 21 and 42, a linear increase of average daily gain (ADG) (p<0.05) during d 21 to 42, a trend in linear increase of ADG (p<0.10) during d 0 to 21 and d 0 to 42, a linear increase of gain to feed ratio (G:F) (p<0.05) during d 0 to 42, and a tendency in the linear increase of G:F during d 21 to 42 were observed in this study. Additionally, dietary supplementation of 0% to 0.10% AJE had a linear increase (p<0.05) on the apparent total tract digestibility of dry matter (DM) and energy, a linear increase (p<0.05) on lactic acid bacteria counts, a tendency in reducing (linear effect, p<0.10) coliform bacteria counts, and a linear decrease (p<0.05) in excreta H2S emission content in growing pigs. Conclusion: In conclusion, the results suggested that AJE had the potential to enhance growth performance, DM and energy digestibility, and fecal lactic acid bacteria counts, and decrease the fecal coliform bacteria counts and excreta H2S emission in growing pigs.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.467-472
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• 1989

In this study, a design method to obtain a robust optimal regulator for linear multivariable system is presented. When assigning eigenvalues of linear multivatiable system , the feedback gain is not unique. So we can assign robustness index to optimality so that we can fully use the remained degree of freedom.

• 전기의세계
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• v.24 no.5
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• pp.103-106
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• 1975

This Paper deals with an applicatoin of Luenberger Observer to the Linear Stochastic Systems. The basic technique is the use of a matrix version of the Maximum Principle of Pontryagin coupled with the use of gradient matrices to derive the gain matix for minimum error covariance. The optimal observer which is derived turns out to be identical to the well-known Kalman-Bucy Filter.

• International Journal of Control, Automation, and Systems
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• v.5 no.2
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• pp.161-169
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• 2007

The PLL equivalent augmented system incorporated with state feedback is proposed in this paper. The optimal value of filter time constant of loop filter in the phase-locked loop control system and the optimal state feedback gain designed by using linear quadratic regulator approach are derived. This approach allows the PLL control system to employ the large value of the phase-frequency gain $K_d$ and voltage control oscillator gain $K_o$. In designing, the structure of phase-locked loop control system will be rearranged to be a phase-locked loop equivalent augmented system by including the structure of loop filter into the process and by considering the voltage control oscillator as an additional integrator. The designed controller consisting of state feedback gain matrix K and integral gain $k_1$ is an optimal controller. The integral gain $k_1$ related to weighting matrices q and R will be an optimal value for assigning the filter time constant of loop filter. The experimental results in controlling the second-order lag pressure process using two types of loop filters show that the system response is fast without steady-state error, the output disturbance effect rejection is fast and the tracking to step changes is good.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2005.11a
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• pp.293-296
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• 2005

This paper presents the design of linear and circular polarization baseball- shaped circular microstrip antenna (BCMA) with 3-dimensional structure using perturbation effect to reduce its size, which runs at 1.575GHz frequency bandwidth. As a result, the size of linear polarized antenna could be reduced up to 23.7% in patch diameter and 41.8% in its area. Linear polarized antenna has -26.04dB of return loss, 69MHz(4.38%) of -l0dB bandwidth, 4.51dBd of gain, and its -3dB beamwidth are 99$^{\circ}$ in E-plane, 83$^{\circ}$ in H-plane. Circular polarized antenna has -17.43dB of return loss, 113.7MHz(7.2%) of -l0dB bandwidth, 2dBd of gain, 2dB of axial ratio and its -3dB beamwidth are 87$^{\circ}$, 86$^{\circ}$ x-axis polarized, 80$^{\circ}$, 84$^{\circ}$ y-axis polarized. It has 82mm of diameter, which is 28.5% of linear polarized CMPA. Therefore, in this paper we verified that baseball-shaped 3-dimensional structure of circular microstrip patch antenna applied with perturbation effect is appropriate for miniaturization.