• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.5
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• pp.10-24
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• 2007

In the dissertation, a power conversion system for fuel cell is composed of a PWM inverter with LC filter in order to convert fuel cell voltage to a single phase 220[V]. In addition, new insulated DC-DC converters are proposed in order that fuel cell voltage is boosted to 380[V]. In this paper, it requires smaller components than existing converters, which makes easy control. The proposed DC-DC converter controls output power by the adjustment of phase-shift width using switch $S_5\;and\;S_6$ in the secondary switch which provides 93-97[%] efficiency in the wide range of output voltage. Fuel cell simulator is implemented to show similar output characteristics to actual fuel cell. Appropriate dead time td enables soft switching to the range where the peak value of excitation current in a high frequency transformer is in accordance with current in the primary circuit. Moreover, appropriate setting to serial inductance La reduces communication loss arisen at light-load generator and serge voltage arisen at a secondary switch and serial diode. Finally, TMS320C31 board and EPLD using PWM switching technique to act a single phase full-bridge inverter which is planed to make alternating current suitable for household

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.2
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• pp.360-369
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• 2008

The solar cells should be operated at the maximum power point because its output characteristics were greatly fluctuated on the variation of insolation, temperature and load. It is necessary to install an inverter among electric power converts by means of the output power of solar cell is DC. The inverter is operated supply a sinusoidal current and voltage to the load and the interactive utility line. In this paper, the proposes a photovoltaic system is designed with a step up chopper and single phase PWM voltage source inverter. Synchronous signal and control signal was processed by one-chip microprocessor for stable modulation. The step up chopper is operated in continuous mode by adjusting the duty ratio so that the photovoltaic system tracks the maximum power point of solar cell without any influence on the variation of insolation and temperature for solar cell has typical dropping character. The single phase PWM voltage source inverter is consists of complex type of electric power converter to compensate for the defect, that is, solar cell cannot be develop continuously by connecting with the source of electric power for ordinary using. It can be cause the efect of saving electric power, from 10 to 20%. The single phase PWM voltage source inverter operates in situation, that its output voltage is in same phase with the utility voltage. The inverter are supplies an ac power with high factor and low level of harmonics to the load and the utility power system.

• Journal of Advanced Navigation Technology
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• v.1 no.1
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• pp.23-34
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• 1997

A multi-channel digital GPS receiver has been developed including a RF-to-IF engine (engine 1), a digital signal processing engine (engine 2) with a microprocessor interfacing, and a navigation software. A high speed SiGe heterojunction bipolar transistor (HBT) as a active device has been mounted on chip-on-board (COB) type hybrid ICs such as LNA, mixer, and VCO in RF front-end of the engine 1 board. A 6-channel digital correlator together with a real-time clock and a microprocessor interface has been realized using an Altera Flex 10K FPGA as well as ASIC technology. Navigation software controlling the correlator for GPS signal tracking, retrieval and storing a message retrieval, and position calculation has been implemented. The GPS receiver was tested using a single channel STR2770 simulator. Successful navigation message retrieval and position determination was confirmed.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.163-167
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• 2008

This paper presents the analysis of tactile effects on different body parts according to the various vibration patterns. The experiments use a vibration pad made of 16 vibration elements in the form of $4{\times}4$ array. The vibration elements are controlled by a 8-bit microprocessor. The sound of gunshot initiates a vibration pattern on different body parts and its sensitivity is measured. The analysis of the experiments lead us to conclude that the vibration pad is the most realistic interface for shooting games and the shoulder part is the most sensitive part in the body. In addition, the most effective vibration pattern is the for the pattern which gives the sensation of spreading out from the center to the outside. This study analyzes the relationship between the human body parts and the tactile sensations by the various vibration patterns. The result of this study will be a good reference for user studies in the field of haptics based on the vibration.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.5
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• pp.61-68
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• 2004

Recently, a fuel cell is remarkable for new generation system. The fuel cell is characterized by low voltage and high current. Therefor, for connecting to general load, it needs both a step up converter and an inverter. The proposed system consists of an isolated DC-DC converter to boost the fuel cell voltage to 380[Vdc] and a PWM inverter with LC filter to convert the dc voltage to single phase 220[Vac]. Also, bi-directional DC-DC converter for fuel cell generation system is composed to improve load response characteristic. In this paper, full bridge converter and the single phase inverter are designed and installed for fuel cell. Simulation and experiment verify that fuel cell generation system could be applied for the distributed generation.

• Journal of IKEEE
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• v.6 no.1 s.10
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• pp.47-53
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• 2002

This paper manufacturing one system and use this separatively, plan, and embody system that apply integration design method in research about characteristic of internal core of 8051 micro-processors and system reusability so that can use as module of other system. The proposed system itself by object style so that reusability may be possible in proposed method and object style for connection between this systems is required. Set on these request and when systems have own information and were linked with other systems, by supplying own information automatic movement itself is realized and system itself embodies ashes so that can be applied to other system. The proposed method in this paper analyzes and compares with existent Z-80 education board, as well as system that propose offers extensibility, it handles most function to software and development period, expense and baud dimension confirmed advantage of and so on that reduce. Also, design for object style system architecture and showed feature that extensibility and portability are augmented.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.3
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• pp.21-30
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• 1990

This paper describes a hardware implementation of the interframe monochrome video CODEC using a MC-CVQ(Motion Compensated and Classified Vector Quantization) algorithm. The specifications of this CODEC are (1) the resolution of image is $128{\times}128$ pixels, and (2) the transmission rates are about 10frames/sec at the 64Kbps channel. In order to design the CODEC under these conditions, it is implemented by a multiprocessor system composed of MC unit, CVQ nuit and decoder unit, which are controlled by microprogramming technique. And the 3~stage pipelined ALU(Arithmetic and Logic Unit) is adopted to calculate the minimum error distance in the MC unit and CVQ nuit. The realized system shows that the transmission rates are 6-15 frames/sec according to the relative motion of the video signal.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.3
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• pp.171-177
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• 2007

In this paper, we have designed and implemented an optical signal processor in order to use in a fiber-optic current CT for electric equipments where its properties were discussed. The fabricated optical signal processor is used to reduce a measurement current error that induced by the effects of intensity variation in the optical output signal due to losses coming from optical components or polarization variation in a PFOCS. Also, the optical signal processor was fabricated in compact/lightweight with unification of opto-electronic transducer part, analog signal process part, and real-time measurement part consisted of a level shift and ${\mu}-processor$. The experiment of optical signal processor has been performed in the range of $0{\sim}7,500A$ using the PFOCS made all fiber-optic components. As a result of experiment, the linearity error of measurement current is less than 1.7% and its average error is less than 0.3% in the range of $1,000A{\sim}7,000A$.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.1
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• pp.17-23
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• 2006

In recent years, RFID has received much attention because of spread usage in industrial applications including factory, material flow, logistics and defense areas. However, there is only CRC-16 for error detection in ISO/IEC 18000-6 Protocols prepared for 860-960 MHz RFID, high error rates are expected in cases of high level of security and noisy envirionment. In this paper, we propose a usage of convolution code as a method for satisfying the high level of security requirement and system error performance.'1'he signal control function is implemented in a microprocessor with RF modulation and the convolutional encoding and Viterbi decoding are implemented in an FPGA chip.'The frame error rates are measured with and without convolution coding under the channel conditions of line-of- sight and non line-of-sight, respectively.

• Journal of Sensor Science and Technology
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• v.2 no.1
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• pp.75-80
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• 1993

This study describes a non-invasive optical sensor and system in order to obtain oxygen saturation of blood, in-vitro. The sensor contains LED 665nm and 805nm of wavelength for light source and PIN photodiode for light detector in flat pack. The sensor system for measurement of oxygen saturation has breadboarded, including signal amplifier, filter, displayer, A/D converter, microprocessor and memory. Experimental set-up for non-invasive measurement of oxygen saturation in-vitro was done. When the variation of oxygen saturation is compared with that of each wavelength, the variation of 665nm is more than that of 805nm by five times. As oxygen saturation varies from 100% to 60%, and the reflection ratio (R805/R665) is changed linearly. The oxygen saturation in $100%{\sim}60%$ range can be measured with about 5% resolution by the developed sensor, such that if this sensor connects with the main artery and vein, the artificial heart can be controlled rapidly and precisely from measurement of the sensor.