• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1482-1484
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• 1996

To apply Magnetic wedges to the motor, comparing with not applying, showes its performance change of efficiency increse, reduction of temperature rise, harmonics, and magnetic noise. The motor specification and test condition are 37kW-4P-380V-60Hz,squirrel-cage, three phase induction motor with semiclosed type slots. The result of load test to compare with nonmagnetic wedges showed 1.5% increment of efficiency at 100% load and $8.0^{\circ}C$ decrement of temperature rise at stator coil. And for developing the magnetic wedge matrial, its manufacturing process was setting and TG-DTA, optical microscope, SEM, bending strength and permeability were investigated into the material made of through the process.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.455-462
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• 2003

Switching PFC converters are widely used not only to comply the power quality specification but also for maximum efficiency. However switching PFC converters generate serious electromagnetic interference(EMI). In this paper to solve this problem, we applied the APW(Anti-Phase Winding) and RPWM(Random PWM) technique to PFC boost converter and obtained good results. Simulation and experimental results show the improved harmonics and reduced EMI effect in air-conditioner system.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.793-797
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• 2003

Switching PFC converters are widely used not only to comply the power quality specification but also for maximum efficiency. However switching PFC converters generate serious electromagnetic interference (EMI). In this paper to solve this problem, we applied the APW(Anti Phase Winding) and RPWM(Ran-dom PWM) technique to PFC boost converter and obtained satisfactory results. Simulation and experimental results show the improved harmonic and reduced EMI effect in air-conditioner system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.12B
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• pp.1733-1740
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• 2001

A monolithic 5 GHz image reject mixer using a 0.5-m GaAs MESFET technology is designed and simulated. The Mixer exhibits a 13.56 dB down-conversion gain, a SSB (Single SideBand) noise figure of 11.91 dB, an input IP3 (third order intercept point) of -3.73 dBm and a PldB (1-dB compression point) of -11.0 dBm. The critical issue in the image reject mixer is the phase accuracy and magnitude balance of the 90 phase shifting network. The proposed image reject mixer realizes a 90 phase shifter on chip. This phase shifting network does not need any phase adjusting to achieve the phase error specification of 3 over a frequency range from 800 MHz to 1GHz. The simulated overall image rejection ratio is better than 50 dB.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.32 no.10
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• pp.897-904
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• 2008

Egg grading machine is used in poultry raising industry to classify eggs by their weight and to pack up them. Packer holder mechanism is a main part of the egg grading machine, of which role is to take eggs fallen from conveyor belt, and afterward to transfer eggs vertically to mold tray. The vertical motion of packer holder is usually driven by slider-crank mechanism or cam. This paper describes development of the cam in packer holder based on kinematic analysis of packer holder mechanism and measurement of acceleration and noise of the cam to verify performance of it. Several cams that are designed and manufactured by the author of this paper according to different design specification are compared to determine the best solution for egg transfer in the packer holder mechanism.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1140-1141
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• 2006

Maglev is a non-contact traffic system in which cars are supported by magnetic force instead of wheels. This is a ground-breaking traffic system providing superior environmental friendliness and cost efficiency due to the minimal noise and vibration offered by its non-contacting nature. We study the present specification and performance of the low speed urban maglev system in Korea and other countries. After set up the test line, to success the "Commercialization of Korean Urban Maglev System" project, we establish proper requirement of maglev system in Korean environment on base of "Daejeon National Science Museum Maglev Establish Project".

• Proceedings of the IEEK Conference
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• 2003.11c
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• pp.11-14
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• 2003

10GBASE-T is 10Gigabit Ethernet over horizontal structured, twisted-pair copper cabling.(1) It aims to transmit data at a speed of 10Gbps at a l00m distance away, through UTP (unshielded twisted -pair) Cat-5e cable 4-pair. This paper looks over the characteristic of media over Cat 5e, 6, 7, and then suggests how much noise should be removed from it in order to offer the transmission speed of 10Gbps as sending data through each physical medium.

• Proceedings of the KIEE Conference
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• 1999.07a
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• pp.424-426
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• 1999

In this paper, the design characteristics, the manufacturing process and the results of performance test on the AC traction motor for urban transit standard E.M.U which is newly developed with applying standardization specification will be introduced. It is reviewed that the design and performance analysis on conventional motors considering system correlation and design constraint and the design optimization through an analysis of electro-magnetic, thermal and dynamic properties. The properties of factory products manufactured by 200 Class VPI process exhibit a excellent performance with a lower noise and vibration, higher efficiency and power factor etc.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.26 no.11A
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• pp.1803-1811
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• 2001

In this paper, Forward Error Correction(FEC) that is satisfied with ITU-T Recommendation J.83, Annex B(North American Data Over Cable Service Interface Specifications(DOCSIS) for Multimedia Cable Network System(MCNS)) is analyzed. The FEC consist of Reed-Solomon(RS) layer, interleaving layer, randomization layer, and trellis coded modulation(TCM) layer. The effects of quantization of input symbol and of trace-back depth in the Viterbi decoder are simulated over AWGN channels.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.882-885
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• 2011

This paper presents testing and self-calibration of RF circuits using MEMS switches to identify process-related defects and out of specification circuits. We have developed a novel multi-tone dither test technique where the test stimulus is generated by modulating the RF carrier signal with a multi-tone signal generated using an Arbitrary Waveform Generator (AWG) with additive white Gaussian noise. This test stimulus is provided as input to the RF circuit and peak-to-average ratio (PAR) is measured at the output. For a faulty circuit, a significant difference is observed in the value of PAR as compared to a fault-free circuit. Simulation is performed for various circuit conditions such as fault-free as well as fault-induced and their corresponding PARs are stored in the look-up table. This testing and self-calibration technique is exhaustive and efficient for present-day communication systems.