• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.1030-1041
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• 2018

The aim of this paper is to design a centrifugal deformation error compensation method with guaranteed performance that allows angular velocity measurement of the magnetically suspended sensitive gyroscopes (MSSGs). The angular velocity measurement principle and the structure of the MSSG are described, and the analytical model of errors caused by MSSG rotor centrifugal deformation is established. Then, an on-line rotor centrifugal deformation error compensation method based on measurement of rotor spinning speed in real-time has been designed. The common issues caused by centrifugal deformation of spinning rotors can be effectively resolved by the proposed method. Comparative experimental results before and after compensation demonstrate the validity and superiority of the error compensation method.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.11
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• pp.1138-1144
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• 2009

The velocity and acceleration of the ground moving target can cause the target position to be displaced and defocused in the SAR image. In this paper, the displacement compensation scheme is presented to correct the displaced position and defocused moving target image in the DPCA based SAR-GMTI system. The influence of the ground moving target due to the velocity and acceleration is analyzed in range and azimuth directions, and its compensation method is presented with the simulation results. The performance of the proposed method is compared with respect to the estimated velocity and defocused quantity in both range and azimuth directions.

• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1472-1481
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• 2001

In this paper, an advanced shift controller that supervises the shift transients with adaptive compensation is presented. Modern shift control systems for vehicle automatic transmission are designe d to provide smooth transients for passengers' comfort and better component durability. In the conventional methods, lots of testing and calibration works have been done to tune gains of the controller, but it does not assure optimum shift quality at all times owing to system variations often caused by uncertainties in shifting hydraulic systems and external disturbances. In the proposed control scheme, an adaptive compensation controller with intelligent supervisor is implemented to achieve improved shift quality over the system variations. The control input pattern which generates clutch pressure commands in hydraulic actuating systems, is updated through a learning process to adjust for each subsequent shift based on continuous monitoring of shifting performance and environmental changes. The proposed algorithm is implemented and evaluated on the experimental test setup. Results from the experimental studies for several operation modes show both improved performance and adaptability of the proposed shift controller to uncertain changes of the shifting environment in vehicle power transmission systems.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.315-324
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• 2016

This study, investigating the differences of public hospital employees' communication, motivation, mutual trust, working conditions, fair compensation, job satisfaction, is to identify the factors affecting organizational performance. Through this, an alternative is suggested, which can maximize organizational performance of hospital employees. The period was from October 5 to October 31, 2014 to collect the data from 232 subjects working in public hospitals. ANOVA and regression analysis were conducted and the finding shows that communication, motivation, mutual trust, working conditions, fair compensation, job satisfaction have a significant difference (p<0.05) based on job categories. In addition, the factors affecting organizational performance were communication and fair compensation (p<0.001) for nursing job, age and employment type (p<0.05) and fair compensation (p<0.001) for Medical Support, motivation and fair compensation (p<0.001) for administrative job. The efforts to improve human resource management in their organization which is able to inspire a sense of belonging should be followed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.4
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• pp.565-571
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• 2021

In this paper, a compensation scheme of frequency selective IQ mismatch for high-performance radar systems based on commercial RFIC's is proposed. Besides, an optimization model and its solution based on the dimension reduction scheme using singular value decomposition are also proposed to design the optimal IQ mismatch compensation digital filter with complex coefficients. The performance of the proposed method had been analyzed through experiments using the IQ mismatch measurement and compensation system implemented on an FPGA board with a target RFIC and compared with the previous method. The experiment result showed a performance improvement of the proposed method over the existing one without noticeable increments in complexities. These performance analysis results showed that the limitation of using commercial RFIC's in high-performance radar systems due to the undesirable maximum SNR cap caused by their IQ mismatches could be overcome by employing the proposed method.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.422-428
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• 2015

This paper proposes a high performance reversible watermarking (RW) scheme based on a novel compensation strategy. RW embeds data into a host image by modifying its pixel values slightly. It is found that certain modified pixels can be compensated to their original values during the proposed embedding procedure. The compensation effect in the RW scheme can improve the marked image quality significantly. By incorporating the pixel selection method, a higher quality image is obtained, which is verified by extensive experiments.

• Journal of Engineering Education Research
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• v.13 no.5
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• pp.76-80
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• 2010

In this paper, the Location Compensation Mechanism using equivalent distance rate ($LCM_{edr}$) for localization system based on SDS-TWR (Symmetric Double-Sided Two-Way Ranging) in wireless sensor network is proposed. The performance of the mechanism is experimented in terms of two types of the localization tracking scenarios of indoor and outdoor environments in university campus. From the experimentations, the compensation ratio in the $LCM_{edr}$ is better than that in SDS-TWR about 90% in indoor/outdoor environments in scenario 1 but also is better than that of SDS-TWR about 91.7% in indoor environment and about 100% in outdoor environment in scenario 2 respectively.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.208.2-212
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• 1997

In a model based friction comensation for a frictional system,the performance of the system is inflenceed by the selection of the friction model. Especially, when a real plant have dynamic friction characteritics, the compensation of friction with a static friction model may deteriorate the perfomance. For the system we constlucted an adaptiv parameter estimation and friction compensation with a newly introduced dynamic friction model proposed by Canudas et.[1]. The model depicts varios frictional phenomena,such as Stibeck effect,frictional memory, Stick-slip motion. Parmeter identification algorithm are followed conventional RLSM adaptive rule. The stability for the closed system was proved by the Lyapunov stability. The result say that if a real system have dynamic friction property,the friction compensation with the dynamic friction model will improve the perfomance moreover static friction model based compensation may lead to the system unstable.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.385-390
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• 2000

This paper deals with the design and simulation of the hybrid power filter to compensate reactive power and harmonic components of nonlinear load. Control target is a 3-phase diode full bridge rectifier with L-R-C nonlinear load, this load is assumed adjustable speed driver(ASD). The hybrid filter consists of a shunt active filter, shunt passive filters and series inductors. Control algorithm is based on instantaneous power compensation theory proposed by H.Akagi and etc. The result from simulation shows the hybrid filter is superior than other filters on the point of compensation performance and low cost. The PSCAD/EMTDC 3.0 is used as simulation tools.

• Journal of Power Electronics
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• v.13 no.4
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• pp.719-728
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• 2013

A novel hybrid active power filter (NHAPF) that can be adopted in high-voltage systems is proposed in this paper. The topological structure and filtering principle of the compensating system is provided and analyzed, respectively. Different controlling strategies are also presented to select the suitable strategy for the compensation system. Based on the selected strategy, the harmonic suppression function is used to analyze the influence of system parameters on the compensating system with MATLAB. Moreover, parameters in the injection branch are designed and analyzed. The performance of the proposed NHAPF in harmonic suppression and reactive power compensation is simulated with PSim. Thereafter, the overall control method is proposed. Simulation analysis and real experiments show that the proposed NHAPF exhibits good harmonic suppression and reactive power compensation. The proposed compensated system is based on the three-phase four-switch inverter, which is inexpensive, and the control method is verified for validity and effectiveness.