• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.19 no.1
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• pp.175-181
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• 2005

This paper proposes the fuzzy-PLL control system for fast response time and precision control of automation systems. The conventional PLL has not only a jitter noise caused from such a demerit of the wide dead zone, but also a long delay interval that makes a high speed operation unable. In order to solve the problems, the proposed system, which provides the improvement in terms of the control region in high speed and precision control, first used the fuzzy control method for fast response time and when the error reaches the preset value, used the PLL method designing new PFD for precision control. The new designed multi-PFD improves the dead zone, jitter noise and response characteristics, which is consists of P-PFD(Positive edge triggered PFD) and N-PFD(Negative edge triggered PFD) and can improve response characteristics to increase PFD gain.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.108-114
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• 2009

This paper proposes the new hybrid adaptive controller for fast response time and precision control of automation system which exist deadzone or non-linearity of system. The proposed system, which provides the improvement in terms of the control region in high speed and precision control, first used the fuzzy control method for fast response time and when the error reaches the preset value, used the PLL method designing PFD improved jitter for precision control. The new designed PFD improves the jitter noise and response characteristic without generating deadzone. The theoretical and experimental studies have been carried out. The presented results from the above investigation show considerably improved performance in the position control of automation system.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1587-1592
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• 2023

Time-encoded imagers (TEI) are important class of instruments to search for potential radioactive sources to prevent illicit transportation and trafficking of nuclear materials and other radioactive sources. The energy of the radiation cannot be known in advance due to the type and shielding of source is unknown in practice. However, the response function of the time-encoded imagers is related to the energy of neutrons or gamma-rays. An improved image reconstruction method based on MLEM was proposed to correct for the energy induced response difference. In this method, the count vector versus time was first smoothed. Then, the preset response function was adaptively corrected according to the measured counts. Finally, the smoothed count vector and corrected response were used in MLEM to reconstruct the source distribution. A one-dimensional dual-particle time-encode imager was developed and used to verify the improved method through imaging an Am-Be neutron source. The improvement of this method was demonstrated by the image reconstruction results. For gamma-ray and neutron images, the angular resolution improved by 17.2% and 7.0%; the contrast-to-noise ratio improved by 58.7% and 14.9%; the signal-to-noise ratio improved by 36.3% and 11.7%, respectively.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.62 no.1
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• pp.12-17
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• 2013

Fault currents are expressed as a combination of harmonic components and exponentially decaying DC offset components, during the occurrence of fault in power system. The DC offset components are included, when the voltage phase angle of fault inception is closer to $0^{\circ}$ or $180^{\circ}$. The digital protection relay should be detected quickly and accurately during the faults, despite of the distortions of relaying signal by these components. It is very important to implement the robust protection algorithm, that is not affected by DC offset and harmonic components, because most relaying algorithms extract the fundamental frequency component from distorted relaying signal. So, In order to high performance in relaying, advanced DC offset removal filter is required. In this paper, a new DC offset removal filter, which is no need to preset a time constant of power system and accurately estimate the DC offset components with one cycle of data, is proposed, and compared with the other filter. In order to verify performance of the filter, we used collecting the current signals after synchronous machine modeling by ATPDraw5.7p4 software. The results of simulation, the proposed DC offset removal filter do not need any prior information, the phase delay and gain error were not occurred.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.277-280
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• 2006

The hydroformability of aluminum alloy sheets at elevated temperatures have been investigated in this study. It is necessary to analyze the variations of the mechanical properties that depend on the forming temperature and the heat conduction during warm hydroforming. Therefore, in this study a coupled simulation of plastic deformation and temperature distribution in the warm hydroforming process is performed and compared with experimental data. The multi-purpose code DEFORM-2D can handle this type of calculations but it takes high computation time if contact heat transfer between die, tube and pressure medium occurs. Experiments were conducted by high temperature tribometer(pin-on-disk) allowing measuring the friction coefficients of the aluminum alloys at several temperatures and these results are applied to the coupled simulation by which the optimal process parameters such as internal pressure and preset temperature on hydroformability can be determined. The comparison of the FE analysis with the experimental results has shown that hydroformability given by bulge height, and temperature distribution of the tube specimen make a little difference with the FE results but the trend predicted by simulation agrees well with experiments.

• Korean Journal of Poultry Science
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• v.27 no.3
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• pp.227-233
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• 2000

Preset study was carried out to evaluate characteristics of lactic acid producing bacteria(LAB) in hen's cecum as probiotics value. Distribution of LAB in intestinal tracts was investigated using 5∼25 weeks - old hens. So, 12 strains to LAB with different morphology were isolated purely. Acid tolerance of LAB tested at pH 1, 2, 3, and 4, and bile resistant also tested at 0, 0.3% and 0.5% bile salt concentration. Growth pattern of LAB observed to 60h. All strains of cecal LAB couldn't survive at pH 1, and decreased linearly survival colony after incubation at pH 2 although some strains could survive for 2h. Most of LAB maintained constant number at pH 3 and 4. The bacterial action could increase linearly at 0% bile salt concentration in all of tested strains. However, only one strain could multiply at 0.3% bile salt, others were influenced by bile salt. That tendency was similar at 0.5% bile salt. Growth was peaked at 12 to 18 h after innoculation. After peak, the decreasing pattern of colony was different to strains which some strains decreased rapidly or maintained for long time. The LAB of hen's cecum was similar to intolerance acidity, but different to resistant to bile salt and growth pattern by strain. So, we choose three strains which have probiocs value, and identified as Lactobacillus amylovorus LLA7, Lactobacillus crispatus LLA9 and Lactobacillus vaginalis LLA11.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.504-504
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• 2000

The flow ratio in the industrial process is usually accomplished by using PID controller with series type ratio. But always the large overshoot and a long rise time may be achieved from this conventional control. These problems are involved to the inexact flow ratio control. In order to avoid this poor performance. the paper presents a designing of the two controller modes for the flow ratio plants. This proposed controller combine the lookup table technique and the well-known PID controller to obtain the fast response and low overshoot of flow ratio control. The PID controller mode will be operated when the flow ratio reaches the preset value while the lookup table technique mode is applied for initial operation. The data in tile table is calculated by the valve sizing equation and convened to the valve position control signal. The experimental results show that the transient and steady state responses of the control systems using the proposed technique can be efficiently obtained when compared with tile conventional controller.

• Agricultural and Biosystems Engineering
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• v.2 no.1
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• pp.31-36
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• 2001

Based on the viscous flow characteristics of gas through capillary tube, a simple and cheap gas mixing system was developed for controlling gas compositions in CA chambers. The gas flow rate through capillary tube had a linear relationship with pressure, (length)$^{-1}$ and (radius)$^4$ of capillary tube, which agreed well with Hagen-Poiseuille’s law. The relationship between flow rate and combined parameters was described as Q=0.000209724($\pi$ r$^4$P/$\mu$L) and the coefficient of determination was 0.9984. The developed system could control gas concentrations in CA chambers within $\pm$0.3% deviation compared to the preset concentrations. It was possible to predict the required time and required gas flow rate for exchanging the gs in CA chamber to a certain concentration of gas by using the mathematical model developed in this study.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.324-327
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• 2014

This paper describes a study on the intelligent LED lighting system implementation applicated environmental reservation setting. The environment variables are preset by ON and OFF time of illuminator and brightness data. The setting data enables to be changed by personal preferences on the selecting menu. It is possible to reduce unnecessary consumption and operation for the lighting system. The system customized by user's environment is convenient for disability by using bluetooth. Thus the system results in cost effective and energy savings. The system performances are examined for convenient operation and energy saving for practicality in implemented system.

• Journal of Digital Convergence
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• v.14 no.4
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• pp.259-265
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• 2016

In this paper, a remote control system capable of monitoring and controlling the temperature of a refrigerator in real time using the ZigBee communication technology is developed. The developed system provides 24-hour surveillance function including temperature maintenance and it is able to determine monitored data from a remote location and to change the setting of the temperature value. In case the value is out of the setting, it is designed for administrators to verify the problem and take action, sending alarms to management server and the emergency to a preset administrator via SMS. Applying this system to refrigerators storing commercial, medical, and experimental material, the real time status such as temperature and malfunction of refrigerator can be managed up to 16 SZM(Slave Zigbee Module) by only one MZM(Master Zigbee Module).