• The Journal of Korean Institute of Communications and Information Sciences
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• v.28 no.10A
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• pp.807-815
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• 2003

MultiCode-CDMA (MC-CDMA) system of chip level MPSK incorporating with clipper (MP-CDMA)[l] shows constant envelope signal which can mitigate the performance degradation due to nonlinear transmit amplifier. In this paper, modulation is modified to carry out differential encoded MPSK rather than MPSK. The modified system is called DMP-CDMA. DMP-CDMA using differential detection has advantages on receiver complexity and pilot overhead. However, it is inferior to coherent detection by about 4.0dB due to inherent power inefficiency of noncoherent detection and the error propagation. Multiple symbol differential detection is employed in order to improve DMP-CDMA using differential detection. As the result, the performance of DMP-CDMA system is improved about 3.6dB compared to differential detection.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.6 s.121
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• pp.620-628
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• 2007

An H-sector horn antenna has a constant beam coverage characteristic and it can be useful for application to a wide band phased array antenna system. In this paper, we designed a broadband E-plane H-sector horn phased-array antenna, which has a 3:1 bandwidth and ${\pm}60^{\circ}$ beam steering capability. An H-sector hem antenna was designed to have $30{\sim}50^{\circ}$ half-power beam width in the principal H-plane. The active reflection coefficient including mutual coupling was calculated using a waveguide simulator, and the active reflection characteristic was improved by mutual coupling over wide frequency range. Using these results, an $8{\times}1$ H-sector phased array antenna was fabricated. The measurement results for the half-power beam width in the principal H-plane and the active reflection coefficient showed a good agreement with the simulation results. The peak-value pattern in the steered radiation beams also agreed well with the active element pattern. The measured active reflection coefficients within the beam steering range are mostly less than 0.3 over the 3:1 frequency range.

• The Journal of the Korea institute of electronic communication sciences
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• v.3 no.3
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• pp.177-182
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• 2008

Because output of multi-code CDMA system adapted high speed data transmission becoming multi-level system use linear amplifier in output stage and complex output signal. Therefore, Multi-Code CDMA system has shortcoming of high price, high complexity etc. Binary CDMA technology that allow fetters in existing CDMA technology to supplement this shortcoming proposed. In binary CDMA system When correlator process high speed data, bottle-neck phenomenon is happened on synchronization acquisition process, it is very important parameter. Because existent correlator must there be advantage that power consumption is small but flow addition of several stages to receive correlation's value, the processing speed has disadvantage because the operation amount is much. Therefore in this paper, proposed correlator has characteristic such as data is able to high speed processing, chip area is independent and power consumption is constant in structure in binary CDMA system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.4
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• pp.886-893
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• 2004

In this paper, active resonator oscillator using active band pass filter with gain, active resonator with negative resistance using transistor(agilent ATF-34143) is designed and fabricated. Proposed active resonator oscillator for local oscillator in ISM band(5.8GHz) is designed with 5.5 GHz oscillation frequency. Designed active resonator oscillator implemented on the substrate which has the relative dielectric constant of 3.38, the height of 0.508mm, and metal thickness of 0.018mm. Active resonator oscillators using active band pass filter with gain show the oscillation frequency of 5.6GHz with the output power of -2dBm and phase noise of -81dBc/Hz at the offset frequency of 100kHz. Active resonator oscillators active resonator with negative resistance show the oscillation frequency of 5.6, 5.8GHz with the output power of -4dBm and phase noise of -91dBc/Hz at the offset frequency of 100kHz.

• 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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.12
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• pp.5469-5476
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• 2011

The purpose of this study was to analyze relating with Faucult's disciplinary power which factors influence a dancer's self-management (weight control)Total 10 ballet major undergraduate students of two respective universities in Seoul and Daijon were selected for the research and the chosen method was an interview with them. After the researchers analyzed the interview result, they found out the following several significant results. The first reason that major ballet dancers control their weight is to show their beautiful figures on the stage and to make their appearances look slender in the mirror. Dancers adapt various methods for effective weight management (diet control) such as dietary control, 1 food intake (potatoes, bananas, grapes, etc), physical force to advise or ingest (injection, taking medicines, reflexology, vomiting, etc.) Then, what is the hidden vision that makes such a practice of weight control maintain? The study presents a "mirror" as a tool of control playing a significant role, in terms that the power of discipline functions automatically in a dancer's body. In addition, another constant factor of dancers' weight management is monitoring each other's performance continuously, which is called "synopticon" Symptoms. Lastly, the fact that a question about placing a ruler could function in the continuous practice was also revealed.

• The Transactions of the Korean Institute of Power Electronics
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• v.14 no.1
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• pp.38-45
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• 2009

To get the constant output, synchronous generator field excitation is controlled by AVR(Automatic Voltage Regulator). Most of ships generator AVR uses the thyristor phase controlled rectifier. However this rectifier is difficult to realize that the fast control system because its control period is slower than MOSFET and IGBT type converter. Therefore, this paper deals with PMG(Permanent Magnet Generator) type digital AVR using MOSFET switch for ships synchronous generator. The composition of this digital AVR is very simple, the generator is under the short circuit accident, the output voltage becomes zero state and AVR can not operate. Thus generator is required to add CBC(Current Boosting Circuit) in an excitation circuit to flow output current. The performance of the proposed system is evaluated on a 10[kVA] experimental prototype circuit in place of real ships generator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.459-462
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• 2010

Response to nerve stimulation platform for implementing measures to detect finger movement has been functioning as an important factor. This stimulated finger on the nerve and muscle responses would vary. In other words, the finger movement of the muscle response to nerve stimulation and sensing Actuator for the H/W development is needed. In addition, a low power embedded CPU based on the top was used. H/W configuration portion of the isolation power, constant current control, High impedance INA, amplifier parts, and the stimulus mode and the Micro-control the status of current, AD converter Low Data obtained through the processing system is implemented.

• The Transactions of the Korean Institute of Power Electronics
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• v.12 no.3
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• pp.191-198
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• 2007

This paper proposes the instantaneous source voltage and phase current control for torque ripple reduction of a high speed miniature BLDC motor. As compared with general BLDC motor, a high speed miniature BLDC motor has a fast electrical time-constant. So the current and torque ripple are very serious in a conventional PWM switching during conduction period. In order to reduce the switching current ripple, instantaneously controlled source voltage is supplied to the inverter system according to the motor speed and load torque. In addition, the fast hysteresis current controller can keep the phase current In the limited band. The proposed method is verified by the computer simulation and experimental results.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.5
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• pp.494-502
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• 2011

Bimodal tram is designed to run on a dedicated path in automatic mode using a magnetic track system in order to realize a combination of the accessibility of a bus and the constant regularity of a railroad. This paper presents design and test results of the series hybrid propulsion system of the bimodal tram on both test track and public road, which uses CNG (Compressed Natural Gas) engine and Lithium polymer battery pack. This paper describes the real-time data measuring equipment for the series hybrid propulsion system of the bimodal tram. Using this measurement equipment, the performance of the prototype vehicle's driving on test track and public road was verified and the fuel consumption and the efficiency of CNG engine have been investigated.