• The KIPS Transactions:PartD
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• v.11D no.2
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• pp.443-452
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• 2004

The paper presents an intelligent space management system for ubiquitous computing. The system is basically a home/office automation system that could control light, electronic key, and home appliances such as TV and audio. On top of these basic capabilities, there are four elegant features in the system. First, we can access the system using either a cellular Phone or using a browser on the PC connected to the Internet, so that we control the system at any time and any place. Second, to provide more human-oriented interface, we integrate voice recognition functionalities into the system. Third, the system supports not only reactive services but also proactive services, based on the regularities of user behavior. Finally, by exploiting embedded technologies, the system could be run on the hardware that has less-processing power and storage. We have implemented the system on the embedded board consisting of StrongARM CPU with 205MHz, 32MB SDRAM, 16MB NOR-type flash memory, and Relay box. Under these hardware platforms, software components such as embedded Linux, HTK voice recognition tools, GoAhead Web Server, and GPIO driver are cooperated to support user-friendly intelligent space.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.117-122
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• 2006

A CMOS LNA based on a single-stage cascode configuration is designed for MB-OFDM ultra-wide band(UWB) systems. Wideband($3.1GHz\~4.9GHz$) input matching is performed using a simple bandpass filter to minimize the chip size and the noise figure degradation. The simulation results using $0.18{\mu}m$ CMOS process parameters show a power gain of 9.7dB, a 3dB band width of $2.1GHz\~7.1GHz$, a minimum NF of 2dB, an IIP3 of -2dBm. better than -11.8dB of input matching while occupying only $0.74mm^2$ of chip area. It consumes 25.8mW from a 1.8V supply.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.435-435
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• 2012

ITER를 비롯한 실증로나 상용로급 토카막에서는 중성빔 가열이나 전류구동을 위해 1MeV이상의 빔 에너지가 요구된다. 빔 출력이 가속전압의 5/2승에 비례함에도 불구하고 양이온 빔의 경우 에너지가 높아지면 빔의 중성화 효율이 급격히 감소하여 ITER NBI의 경우 양이온 빔의 중성화 효율은 0%에 가깝다. 한편 음이온 빔은 1MeV 이상의 에너지영역에서도 빔 에너지와 거의 무관하게 60% 정도의 중성화 효율을 갖는다. 따라서 ITER는 음이온 빔을 바탕으로 한 중성빔 가열장치(N-NBI)를 채택하고 있다. 우리나라의 핵융합연구가 핵융합 발전을 지향하는한 N-NBI에 대한 연구를 시작해야 하며 그 출발점으로 음이온원 개념설계를 시작하였다. 개념설계는 음이온원 개발과정을 통해 1) 음이온 생성원리 규명, 2) 음 이온원 핵심기술 확보, 3) 음이온 및 음이온 빔 관련 진단 등을 연구할 수 있는 축소규모의 proto-type 음이온원 개발을 목표로 하였다. 음이온원 개발은, 초기에는 KAERI NB test stand 및 KAERI 이온원의 플라즈마 버켓을 활용하기 위해 filament-arc type으로 시작하지만 어느정도 기반이 확립되면 플라즈마 버켓의 electron dump를 제거하고 그 자리에 RF driver를 장착하여 궁극적으로 RF 음이온원을 개발할 계획이다. 본 학회에 발표하는 포스터는 filament-arc type 음이온원에 대한 개념설계이다. 설계된 음이온원은 Tent-type 자장필터를 장착하며, 0.5A의 수소 음이온빔 인출을 목표로 하고 있다. 이를 위해 플라즈마 버켓, 세슘 공급시스템, bias plate, 플라즈마 그리드, electron deflection 자석이 설치된 인출 그리드, 접지 그리드 등에 대한 개념설계가 이루어 졌다. 이 외에도 음이온원 전원과 진단 시스템에 대해서도 논의하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.12
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• pp.2264-2270
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• 2006

This paper describes fast-hewing frequency synthesizers for multi-band OFDM(MB-OFDM) ultra-wide band(UWB) systems. Three different structures in generating 3 center frequencies(3432MHz, 3960MHz, 4488MHz) are designed and compared. The first structure generates 3 center frequencies using only one PLL operating at 4224MHz, and the second uses three PLLs operating at corresponding center frequencies. The proposed third structure employes two PLLs operating at 3960MHz and 528MHz. Simulation results using 0.18um RF CMOS process parameters show that the third structure exhibits boner characteristics in spur, area and current consumption than the other structures. The band switching time of the proposed synthesizer is less than 1.In and the spur is less than -36dBc. The synthesizer consumes 22mA from a 1.8V supply.

• Journal of Korean Society of Transportation
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• v.32 no.3
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• pp.248-255
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• 2014

Though the Platform Screen Door System (PSD) has received a positive evaluation and is installed in all the Urban Railroad platforms, PSD is not installed in the Intercity Railroad platforms. The limitation of PSD in the Intercity Railroad platforms is due to the fact that first, various types of trains such as KTX, Saemaeul, Mugunghwa, and Nuriro stop at the platforms and their locations of the doors are different and secondly, they are not operated under ATO (automatic train operation). RPSD system currently under research and development, on the other hand, is based on the improved door that slides up and down and can be installed in any Intercity Railroad platform regardless of the length of the train, the location of doors, and the number of doors. This study considers the mechanism of RPSD, develops a manual open/close algorithm, and evaluates the function of RPSD. The results show that the manual open/close algorithm achieves a significant improvement in efficiency when provided with power supply.

• Journal of Navigation and Port Research
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• v.28 no.10 s.96
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• pp.955-960
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• 2004

The treated ballast water from previous treatment contains microorganisms and pathogenic organisms in an electrolytic treatment system. The experimental methods included using a peristaltic flow pump placed upward on an electrode pole. Due to the reaction time, the hydraulic retention time indicated unlike microorganisms on the flow rate. In electrolysis, dioxide iridium-coated titanium (Ti/Ir02) and stainless steel plates were used for the anode and cathode, respectively. Current density controls make use of a DC power supply on 250V, 100Amper. Experimental use of a current density between 0.1 and 1.0A/dm2 was able to disinfect the microorganism (E. coli, Bacteria, Bacillus sp.) in seawater for 5 seconds of reaction time. The removal rate was approximately $90\%,$ while the current density was 2.0A/dm2 and the electrode distance was 75mm. This study shows that the electrolytic treatment system has a potential for the sterilization of ballast water.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.10
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• pp.5105-5114
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• 2013

This paper is conducted a research of the cable and filter design considering the deep sea floor environment. The electric architecture which is being used in the subsea plant is comprised of the power supply unit of the high voltage, high-capacity drive system, long cable, and electric motor in the sea area. Conducted emission is occurred by the rapid voltage change at the moment of switching at high speed of inverter for driving motors. The more the length of the cable is lengthened, the worse the motor is influenced by transient voltage. Thus, the over voltage occurred in the drive motor was confirmed by designed wire which is considered R, L, line-to-line C, line-to-gnd C of long cable used in the subsea plant. A guide line of the subsea plant model is also suggested by using a filter to reduce conducted noise of PWM inverter drive-system.

• Journal of Convergence Society for SMB
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• v.1 no.1
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• pp.55-65
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• 2011

Due to the rapid advance of IT technologies such as mobile communication, sensor network, wearable computer, and so on, the needs of embedded software has increased. In those domain areas, the development of low-power embedded software is one of critical issues to enhance servicability of the system because almost embedded system depends on battery-based power supply system. Therefore this paper identifies the factors that can reduce the power consumption in embedded software operation, and proposes the method that how to handle the factors in software development process. Even though the existing and general studies about power reduction has been performed with code-based analysis, this analysis approach can lead reworks when the requirement for power consumption was not met. Our proposed techniques will support the power reduction in embedded software development process whenever the code was not developed. Our proposed process for lop-power embedded software development can gives the high quality in power-related serviceability.

• The Journal of the Acoustical Society of Korea
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• v.31 no.5
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• pp.309-316
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• 2012

This paper suggest configuration method of small-size system and design method of module using multi power. In particular module designed to focus on PDN(Power Distribution Network) and filter configuration method to improve the characteristics of noise sensitive analog IC. For the prevention of high-voltage noise, manufactured module is used the ground-isolated technique and via stitching, and is connected grounds with a series of filters. In this paper, so we analyzed PDN structure through the simulation using lumped modeling and confirmed through measurement. Simulation results, when connecting 4.7uH inductor, we made certain that noise of -7dB decreases much more than when it did not. And it was confirmed 12% less than Background Noise.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.2
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• pp.273-278
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• 2011

This paper has proposed a dual-band transmitter RF Front-end for IMT-Advanced systems which has been implemented in a 0.13-${\mu}m$ CMOS technology. The proposed dual-band transmitter RF Front-End covers 2300~2700 MHz, 3300~3800 MHz frequency ranges which support 802.11, Mobile WiMAX, and IMT-Advanced system. The proposed dual-band transmitter RF Front-End consumes 45 mA from a 1.2 V supply voltage. The performances of the transmitter RF Front-End are verified through post-layout simulations. The simulation results show a +0 dBm output power at 2 GHz band, and +1.3 dBm output power at 3 GHz band.