• Journal of the Institute of Electronics Engineers of Korea CI
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• v.37 no.5
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• pp.45-53
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• 2000

This paper presents an analysis of the dynamical behavor in the chaotic neuron fabricated using 0.8${\mu}{\textrm}{m}$ single poly CMOS technology. An approximated empirical equation models for the sigmoid output function and chaos generative block of the chaotic neuron are extracted from the measurement data. Then the dynamical responses of the chaotic neuron such as biurcation diagram, frequency responses, Lyapunov exponent, and average firing rate are calculated with numerical analysis. In addition, we construct the chaotic neural networks which are composed of two chaotic neurons with four synapses and obtain bifurcation diagram according to synaptic weight variation. And results of experiments in the single chaotic neuron and chaotic neural networks by two neurons with the $\pm$2.5V power supply and sampling clock frequency of 10KHz are shown and compared with the simulated results.

• Plant Journal
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• v.14 no.1
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• pp.47-51
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• 2018

This study analyzed the effect of power output reduction in coal fired power generation on the change of system marginal price and green house gas emissions. Analytical method was used for electricity market forecasting system used in korea state owned companies. Operating conditions of the power system was based on the the 7th Basic Plan for Electricity Demand and Supply. This as a reference, I analyzed change of system marginal price and green house gas emission by reduced power output in coal fired power generation. The results, if the maximum output was declined as 29 [%] to overall coal-fired power plant, system marginal price is reduced 12 [%p] compared to before and decreasing greenhouse gas emissions were 9,966 [kton]. And if the low efficiency coal fired power plant that accounted for 30 [%] in overall coal-fired power plant stopped by year, system marginal price is reduced 14 [%p] compared to before and decreasing greenhouse gas emissions were 12,874 [kton].

• Journal of the Korean Society for Railway
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• v.16 no.4
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• pp.241-245
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• 2013

In the case of the existing train control system, the driver monitors the condition of the vehicle through a composite controller device that displays various information on a screen in the vehicle. However, when problems arise such as car trouble, it is difficult for the drivers to take action immediately. In addition, maintenance personnel have to manually save data one by one after storing the vehicle to analyze control information of the main devices such as the brake controller and auxiliary power. To improve these points, a system that sends and receives all information in real time should be established by installing a sensor communication network and a surveillance system. This study attempts to improve the safety and maintenance of rail vehicles by suggesting a standardized method for train control and surveillance system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.3
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• pp.380-388
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• 2011

In this paper, we developed the X-band 63 watt pulsed SSPA(Solid State Power Amplifier) by using HMIC(Hybrid Microwave Integrated Circuits). The pulsed SSPA consists of power supply and 3-stage amplifier modules : pre-amplifier stage, driver-amplifier stage, final-amplifier stage. The developed pulsed SSPA provides more than 63 watts of output power with a short pulse width and the duty cycle of up to 1.2 % at $70^{\circ}C$. The fabricated module offers great than 37 dB of saturated gain across the operating band. Input and output VSWR is <1.5:1. This module has an average current of 400 mA typical and operates at a +28 $V_{dc}$ supply. The developed SSPA in this paper can apply to pulsed Doppler radar with high speed operation.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.23 no.7
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• pp.784-790
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• 2012

In this paper, an all-digital CMOS ultra-wideband(UWB) pulse generator for high band(6~10 GHz) frequency range is presented. The pulse generator is designed and implemented with extremely low power and low complexity. It is designed to meet the FCC spectral mask requirement by using Gaussian pulse shaping circuit and control the center frequency by using CMOS delay line with shunt capacitor. Measurement results show that the center frequency can be controlled from 4.5 GHz to 7.5 GHz and pulse width is 1.5 ns and pulse amplitude is 310 mV peak to peak at 10 MHz pulse repetition frequency(PRF). The circuit is implemented in 0.13 um CMOS process with a core area of only $182{\times}65um^2$ and dissipates the average power of 11.4 mW at an output buffer with 1.5-V supply voltage. However, the core consumes only 0.26 mW except for output buffer.

• Journal of Biomedical Engineering Research
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• v.23 no.5
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• pp.397-403
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• 2002

Urine glucose monitoring system is a self-monitoring system that display the glucose level by non-invasive measurement method. In this paper, We developed a noninvasive urine glucose monitoring system that improved defects of urine glucose measurement with a colorimeter method and invasive blood glucose measurement method. This system consist of bio-chemical sensor for urine glucose measurements, signal detecting part, digital and signal analysis part, display part and power supplying part. The developed bio-chemical sensor for the measurement of urine glucose has good reproducibility, convenience of handing and can be mass-produced with cheap price. To evaluate the performance of the developed system, We performed the evaluation of confidence about the detection of glucose level by a comparison between a standard instrument in measuring glucose level and the developed system using standard glucose solutions mixed with urine. Standard error was 2.85282 from the evaluation of confidence based on regression analysis. Also, In analysis of S.D(standard deviation) and C.V(coefficient of validation) that are important parameters to evaluate system using bio-chemical sensor, S.D was 10% which falls under clinically valid value, 15%, and C.V was under 5%. Consequently from the above results, compared to blood glucose measurement, the system performance is satisfactory.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.469-472
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• 2004

This paper proposed and analyzed the Serial Piston Actuator(SPA) by using mechanical spring system coupled with linear actuator though the simplified structure which was verified practical experiments. The input voltage characteristics of a linear actuator are analyzed on the structure of the Linear Actuator Model System. Simulation and experimental result have been performed for the verification of the proposed system and the voltage characteristics applied to a actuator winding by electromechanical energy conversion theory. This paper proposed and analyzed the Linear Actuator Model(LAM) by using Matlab program with linear actuator was verified computer simulation based on the energy conversion theory.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.12B
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• pp.1115-1123
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• 2003

In this paper, a remote control system called TeleRemote system which can be applied to existing wireless mobile networks or public telephone networks for remote control is designed and implemented. The proposed design employs program technology based on the theory of signal detect control and enables the EPG(Electronic Program Guide) functions such as recording reservation of bidirectional video signals with TV reception card on PC. It can also control recording reservation using remote control program through telecommunication network The PC-EPG system is implemented in Web programs with Server/Clinet architecture and the server system that provides EPG functionalities is in charge of recording reservations and data communications by means of the scheduler program. Data storing to client PCs is performed through TCP/IP and finished by client programs implemented using Visual C++/MFC programs. As remote control system, the developed system can be used for unmanned security system using the Web camera. Building intranet and making connection to internet, the TeleRemote system is believed to create potential for commercial communication system.

• Journal of Energy Engineering
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• v.16 no.4
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• pp.181-186
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• 2007

In order to investigate the heat transfer coefficient and pressure drop during evaporation of $CO_2$, basic experiment on the evaporation heat transfer characteristics in a horizontal smooth tube was performed. The experimental apparatus consisted of a test section, a DC power supply, a heater, a chiller, a mass flow meter, a pump and a measurement system. Experiment was conducted for various mass fluxes ($200{\sim}1200\;kg/m^2s$), heat fluxes ($10{\sim}80\;kW/m^2$) and saturation temperatures ($-5{\sim}5^{\circ}C$). With the increase of quality, the evaporation heat transfer coefficient decreased. With the increase of heat flux, the evaporation heat transfer coefficient increased. Significantly change of the heat transfer coefficient was observed at any heat flux and mass flux. With the increase of saturation temperature, the heat transfer coefficient increased. Pressure drop increased with the increase of mass flux and the decrease of saturation temperature.

• Analytical Science and Technology
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• v.13 no.4
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• pp.474-483
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• 2000

An inductively coupled plasma atomic emission spectrometer/shielding system was specially designed and built for the analysis of radioactive materials. Both of an inductively coupled plasma source and a sample transfer system to be contacted with radioactive materials was installed in a stainless steel glove box. In terms of analytical capability and radiation safety, characteristic feature of the system was investigated. Its applicability to the determination of fission products and corrosion products in the radioactive materials such as spent fuel dissolver solution and the primary coolant of nuclear power reactors was evaluated. In the concentration range $0.01-0.1mgL^{-1}$, the relative standard deviation was found to be less than 5%.