• Journal of Power Electronics
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• v.4 no.2
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• pp.96-101
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• 2004

This paper presents an application of SRM drive for LSEV(Low Speed Electric Vehicle). In this paper, a 5〔㎾〕 SRM for a traction of a LSEV is to design and investigate the characteristics of the drive system. The main design parameters and control strategy are given. In the control method, a current control, for the soft-starting technique at a starting operation, is adopted. In the high speed range, an angle control technique is implemented, for a high efficiency drive of SRM. Some experimental tests are executed to find the drive performances.

• Vacuum Magazine
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• v.3 no.4
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• pp.4-7
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• 2016

An X-ray Free Electron laser facility (PAL-XFEL) has been built in Pohang Accelerator Laboratory to provide X-ray FEL radiations for photon users. The machine consists of a 10 GeV normalconducting S-band linear accelerator and two undulator beamlines. The hard and soft X-ray beamlines will provide FEL radiations with wavelengths of 0.6 to 0.1 nm and 4.5 to 1 nm, respectively. Beam commissioning of PAL-XFEL is ongoing and user service will start in 2017. In this report, the PAL-XFEL layout and the working principle are discussed.

• Journal of the Korean Professional Engineers Association
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• v.34 no.2
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• pp.42-45
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• 2001

This Grand Sorae Bridge was built in order to lead to balanced reigoonal development by linking the 2nd Seoul - Inchon Highway to WestCiast Highway and it will contribute to develop the economy of the region and traffic of its vicinities by helping ease traffic in and around Inchon. It extends 470 meter across Sorae port by using 10 continuous steel box griders under benoto(all casing) system considering ultra soft ground condition of the site.

• Journal of Electrical Engineering and Technology
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• v.11 no.5
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• pp.1265-1273
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• 2016

• Journal of IKEEE
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• v.16 no.2
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• pp.109-115
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• 2012

We propose a control system consisted of TRIAC PWM module and sequential start control system attenuating voltage-dip and inrush current caused by starting of inductive load network. To minimize the high voltage-dip and inrush current induced from a large capacity inductive load, we developed a TRIAC PWM module. And we also developed a sequential start control system preventing simultaneous starting of the inductive loads within a same power network. According to the experimental results with the proposed control system, the voltage-dip and inrush current could be effectively attenuated such that they can meet the related international standards and resolve the issues associated with simultaneous starting of multiple inductive loads. By employing this system, power cost usually implemented by the estimation of peak power consumption can be reduced and the power quality of a power distribution system connected to the inductive load network can be stabilized efficiently.

• Journal of IKEEE
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• v.24 no.1
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• pp.319-325
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• 2020

In this paper, a discontinuous-conduction mode (DCM) DC-DC buck converter is presented for mobile device applications. The buck converter consists of compensator for stable operations, pulse-width modulation (PWM) logic, and power switches. In order to achieve small hardware form-factor, the number of off-chip components should be kept to be minimum, which can be realized with simple and efficient frequency compensation and digital soft start-up circuits. Burst-mode operation is included for preventing the efficiency from degrading under very light load condition. The DCM DC-DC buck converter is fabricated with 0.18-um BCDMOS process. Programmable output with external resistors is typically set to be 1.8V for the input voltage between 2.8 and 5.0V. With a switching frequency of 1MHz, measured maximum efficiency is 92.6% for a load current of 100mA.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.398-401
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• 2011

This paper presents a high-efficiency CMOS PWM DC-DC buck converter. It generates a constant output voltage(1-2.8V), from an input voltage(3.4-3.9V). Inductor-based type is chosen and inductor current is controlled with PWM operation. The designed circuit consists of power switch, Pulse Width Generation, Buffer, Zero Current Sensing, Current Sensing Circuit, Clock & Ramp generation, V-I Converter, Soft Start, Compensator and Modulator. Switching Frequency is 1MHz, It operates in CCM when the load current is more than 40mA, and the maximum efficiency is 98.71% at 100mA. Output voltage ripple is 0.98mV(input voltage:3.5V, output voltage:2.5V). The performance of the designed circuit has been verified through extensive simulation using a CMOS $0.18{\mu}m$ technology.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.3
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• pp.302-308
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• 2011

The HVAC(Heating Ventilation and Air Conditioning) system is only controlled by turn on/turn off operations with AC 380V input. Therefore, the efficiency of the system is reduced and accoustic noise problem occurs. Also, the blower is shut down at the AC power failure. In this paper, the inverter system with UPS function for the A/C(Air Conditioning) blower is proposed. Proposed inverter system which is powered from the AC and DC voltage can control speed, operation mode, and soft-start time using CAN communication. In case of the CAN communication failure, RS-232 communication could be used to control the hardware directly by the engineer that can solve existing problems. To verify the validity of proposed inverter system, simulations and experiments are carried out.

• Journal of the Korean Society of Clothing and Textiles
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• v.29 no.3_4 s.141
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• pp.403-413
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• 2005

The purpose of this study is to interpret the elegant dressing visualized in modem fashion on the basis of the concept of elegance in dress and its aesthetic characteristics from the holistic viewpoint. Elegance in dress is based upon the idea of aristocratic taste cultivated by good breeding, considering from the documentary study. It is expressed visually through not only the carefully contrived dress but also a sort of aura of dressed body with skillful ease. The aesthetic values of elegance consist of luxury, nobility, refinement, femininity, harmony. To grasp the trends of elegant styles since 1990s, contents analysis of the articles related to elegance in Vogue has been done. As a result, they have been classified into four groups of elegant styles which are Classic, Elaborate Couture, Soft Minimalism, Kitsch Elegance. Classic Elegance and Elaborate Couture Elegance represent traditional ones with conservative viewpoint. Soft Minimalism Elegance is a modem version of elegance. According to postmodernism as a open system, even kitsch has been refined to keep accompany with elegance fur aristocratic taste of high class. As a result of this study, in fashion from the 16th century to the first half of 16th century, elegance has been one of the significant aesthetic categories, resulting from the absolute domination of taste of high society. However in the end of 20th century it seems to start to fade in fashion trends such as mass fashion, youth culture, casual fashion etc. Rather, it can be thought that elegance has been expressed as one of the aesthetic values in dress, by virtue of its value of high class as well as its conservative stability.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1A
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• pp.26-34
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• 2002

Mobile telecommunication systems such as IS-95 and IMT-2000 employ frame based communication using frames up to 20 msec in length and the receiving end has to store the whole frome before it is being processed. The size of the frame buffer ofter dominates those of the processing unit such as soft decision Viterbi decoder. The frame buffer for IMT-2000, for example, has to be increased 80 times as large as that of IS-95. One of the parameters deciding the number of bits in a frame will be obviously the number of bits in soft quantization. Start after striking space key 2 times. This paper has studied a new aspect of offset and quantization step size on BER performance and proposes a new 3-bit soft quantization algorithm which shows similar performance as that of 4-bit soft decision Viterbi receiver. The optimal offset values and step sizes for the other practical quantization levels ---16, 8, 4, 2--- have also been found. In addition, a new optimal symbol metric table has been devised which takes the accumulation value of various repeated signals and produces a rescaled 3-bit valu.tart after striking space key 2 times.