• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.71-76
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• 2014

In this paper, we propose a SMMA(Sliced-Multi Modulus Algorithm) adaptive blind equalization algorithm with Flag for high order QAM system. SMMA has improved characteristics by applying the multi contour to MMA. However, SMMA still has a limit that the mismatch problem causes the residual error in the steady state is large. In order to significantly reduce the residual error in the steady state, we propose SMMA, which is controlled by the binary Flag of '1 'or '0' obtained from SMMA and a decision-directed algorithm, and analyze the performance of the proposed algorithm. By computer simulation, it is confirmed that the proposed algorithm has improved performance highly in terms of a residual ISI and a residual error in the steady state compared with MMA and SMMA.

• Journal of Power Electronics
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• v.18 no.5
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• pp.1398-1408
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• 2018

In order to further improve the steady-state control performance of model predictive torque control (MPTC), a double-vector-based model predictive torque control without a weighting factor is proposed in this paper. The extended voltage vectors synthesized by two basic voltage vectors are used to increase the number of feasible voltage vectors. Therefore, the control precision of the torque and the stator flux along with the steady-state performance can be improved. To avoid testing all of the feasible voltage vectors, the solution of deadbeat torque control is calculated to predict the reference voltage vector. Thus, the candidate voltage vectors, which need to be evaluated by a cost function, can be reduced based on the sector position of the predicted reference voltage vector. Furthermore, a cost function, which only includes a reference voltage tracking error, is designed to eliminate the weighting factor. Moreover, two voltage vectors are applied during one control period, and their durations are calculated based on the principle of reference voltage tracking error minimization. Finally, the proposed method is tested by simulations and experiments.

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.2
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• pp.32-38
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• 2004

A comprehensive understanding is given for the hot-firing test results, which were obtained throughout the verification program of mono-propellant hydrazine rocket engines (thrusters) producing 0.95 lbf (4.2 N) of nominal steady-state thrust at an inlet pressure of 350 psia (2.41 Mpa). A scrutiny for the engine performance is made in terms of thrust and temperature behavior of steady state firing mode at the given propellant injection pressures: Pinj = 400, 250, 100, and 50 psi. The thrust and specific impulse are compared with a reference performance of 1-lbf standard rocket engines and their normalization procedure is introduced. A practical engineering approach to the data measurement and reduction is addressed, too.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.47 no.1
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• pp.46-58
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• 2011

A steady-state analysis and a simple dynamic model as simplified methods are developed, and results of energy consumption loads are compared with results obtained using computer to evaluate the analytical solution. Before obtaining simplified model a mathematical model is formulated for the effect of wall mass on the thermal performance of four different houses having various wall construction. This analytical study was motivated by the experimental work of Burch et al. An analytical solution of one-dimensional, linear, partial differential equation for wall temperature profiles and room air temperatures is obtained using the Laplace transform method. Typical Meteorological Year data are processed to yield hourly average monthly values. This study is conducted using weather data from four different locations in the United States: Albuquerque, New mexico; Miami, Florida; Santa Maria, California; and Washington D.C. for both winter and summer conditions. The steady state analysis that does not include the effect of thermal mass can provide an accurate estimate of energy consumption in most cases except for houses #2 and #4 in mild weather areas. This result shows that there is an effect of mass on the thermal performance of heavily constructed house in mild weather conditions. The simple dynamic model is applicable for high cycling rates and accurate values of inside wall temperature and ambient air temperature.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.5
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• pp.15-21
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• 2008

It is generally known that the PRAT(Plysteer Residual Aligning Torque) is one of indicating a performance factors of a tire for assessing the vehicle pull, also tire pattern shape, which means lateral groove angle, is very important tire design factor in relation to the PRAT. Lateral grooves of tire pattern are widely divided into center and shoulder parts. So, this paper has studied the correlation between the PRAT and their lateral groove angles using FEM. Especially, the steady state rolling analysis among tire rolling analysis methods has been used for the PRAT performance study. Firstly, analysis result data have been compared with the experimental data to validate FE analysis for PRAT. Next, the PRAT due to the lateral groove angle about PCR(Passenger Car Radial) tire and SUV tire has been analyzed. The tendency of the PRAT due to the lateral groove angles can be used as a guide line for the tire design in relation to vehicle pull.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12A
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• pp.983-990
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• 2003

In this paper, a noncoherent code tracking loop is designed for 3GPP MODEM and its performance is analyzed in terms of steady-state jitter variance and transient response characteristics. An analytical closed-form formula for steady-state jitter variance is Int derived for AWGN environments as a general function of a pulse-shaping filter, timing offset, signal-to-interference ratio, and loop bandwidth, together with the analysis on the transient response characteristic of a tracking loop. Based on the analysis, the code tracking loop with variable loop bandwidth that is efficient for full digital H/W implementation is designed and its performance is compared with that of the code tracking loop with fixed loop bandwidth, along with the verification by computer simulations.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.4
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• pp.137-143
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• 2010

This paper deals with the performance comparison of self adaptive equalizer by the weighting factor of MCMA cost function for the compensate the amplitude and phase distortion which occurs in the communication channel. The MCMA is improves the cost function of present CMA at the output of equalizer for the minimize of error function in the amplitude and phase, the value of weighting factor is used at this time. When the comparison of equalizer performance, we classified to initial state and steady state, then it represents the convergence time and convergence speed and steady state operation of equalizer to the predetermined level, it is determined by the weighting factor. We confirm to the different result to this 2 state by weighting factor values using computer simulation. By using the result of this paper, if we appropriately choose the weighting factor values in the environment of communication channel, it is expected that the high quality digital transmission is possible.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.309-312
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• 1997

The dynamic characteristics of a continuous MMA/MA free-radical solution copolymerization reactor were studied. A mathematical model was developed and kinetic parameters which had been estimated in the previous work were used. With this model, bifurcation diagrams were constructed with various parameters as the bifurcation parameter to predict the region of stable operating conditions and to enhance the controller performance. It was shown that the steady-state multiplicity existed over wide ranges of residence time and jacket inlet temperature. Periodic solution branches were found to emanated from Hopf bifurcation points. Under certain conditions isola was also observed, which would result in poor performance of feedback controllers.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.3
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• pp.53-58
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• 2020

This paper is concerned with the performance analysis of MSAGF-MMA with variable step size whose step size varies according to input power signal and decision-directed error signal. The proposed algorithm is made to change according to the input power signal which can reliably increase the convergence speed to the steady state by making the step size less affected by the fluctuation of the input signal in the MMA having the binary flag obtained from the modified Stop-and-Go algorithm. At the same time, the step size can be varied according to the decision-directed error signal so that the residual error can be reduced in the steady state. As a result of computer simulations, it is confirmed that the proposed algorithm has a very good performance in the evaluation of residual ISI and averaged-MSE in steady state as well as in terms of convergence speed to steady state compared to MMA and MSAGF-MMA.

• Journal of Power Electronics
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• v.8 no.3
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• pp.268-274
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• 2008

This paper presents a proposed position controller for a vector controlled induction motor. The position controller design depends on the rotational motion equations and a classical speed controller (CSC) performance. The CSC is designed to have the ability to track variable reference inputs and to provide a predefined system performance. Standard position controller in industry is presented to analyze its performance and its drawbacks. Then the proposed position controller is designed, based on the well defined rotational motion equations. The proposed position controller and the CSC are applied to control the position and speed of the vector controlled induction motor with different ratings. Simulation results at different operating conditions are presented to evaluate the proposed controllers' performance. The results show that the CSC can drive the motor with a predefined speed performance and can track a variable reference speed with an approximately zero steady state error. The results also show that the proposed position controller has the ability to effect high-precision positioning in a limited time and to track a variable reference position with a zero steady state error.