• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.257-262
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• 2003

Base isolation bearings are known as an effective system to Protect bridges from the earthquake damage. There are many types of base isolation bearings in the market. Among them, steel hysteretic damper, made of mild steel and one of the oldest ones, has some good features. Since steel hysteretic damper is made of steel and has simple structure, it is cheeper and easier to maintain than other types. Despite the advantages, steel hysteretic damper with pin-type elements has no application in Korea. The steel hysteretic damper with pin-type elements are tested to examin the basic characteristics and to evaluate antiseismic performance. In this paper, the results of the test are presented.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.405-410
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• 2002

In this paper, numerical method of evaluating the influence of Dual Mass Flywheel(DMFW) to the torsional vibration of the automotive power train system is developed. And we applied the procedure to the currently being developed HMC's DMFW attached to an FF car to find out the best performance characteristics during the Tip-in/Tip-out operating condition. In doing this we compared the numerical results with the experimental results and Performed Parametric studies. We find out that the torsional vibrational characteristics of power train system can be significantly improved when we optimally choose DMFW, and the developed numerical procedure could be used as valuable tools in developing new DMFW.

• Proceedings of the KIEE Conference
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• 2001.04a
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• pp.277-280
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• 2001

This paper presents a speed sensorless implementation of digital speed control system of Surface Permanent-Magnet Synchronous Motor(SPMSM) drives with a direct torque control(DTC). The system presented are stator flux and torque observer of stator flux feedback control model that inputs are current and voltage sensing of motor terminal with estimated rotor angle for a low speed operating area, two hysteresis band controllers, an optimal switching look-up table, rotor speed estimator, and IGBT voltage source inverter by using fully integrated control software. The developed speed sensorless control system are shown a good motion control response characteristic results and high performance features using 1.0Kw purposed servo drive SPMSM.

• Proceedings of the KIEE Conference
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• 1994.07a
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• pp.290-293
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• 1994

This paper proposes a servo control system of SPMSM (Surface-mounted Permanent Magnet Synchronous Motor) which essentially uses vector control method. The control system is composed of the PI controller for speed control and the current controller using space voltage vector PWM technique. The high-speed processing of algorithm for vector control and inverter switching for PWM is carried out by TMS320C31 DSP and IGBT module, respectively. The proposed scheme for 2.2kW SPMSM is verified through digital simulations and experiments, which show higher performance than that of traditional hysteresis current control technique.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.792-793
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• 2006

In the paper, the influence of different particle size $D:D>125{\mu}m$, $D<50{\mu}m$ and between on magnetic properties of a standardized dielectromagnetic is presented. The tests were taken at frequencies of between 50Hz, and 500Hz. Presented in the paper results provide important materials property data to allow the selection of the most appropriate dielectromagnetic particle size for different applications.

• Journal of Electrical Engineering and Technology
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• v.13 no.2
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• pp.699-703
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• 2018

Flux-switching permanent magnet machines (FSPMM) have doubly-salient and simple structures making it cost effective and suitable for mass production. In addition, it is possible to increase the rotor rotating speed and concentrate the flux of the permanent magnet on the air-gap. Due to these merits, the FSPMM can be applied to the various industry applications. To improve the performance, various design variables need to be studied in terms of design techniques. In this paper, we especially concentrate on the distribution of iron losses using a two-dimensional finite-element method (2D FEM). As a result, we can get an information for high efficiency FSPMM design.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.16 no.9
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• pp.765-770
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• 2003

We have developed a low-temperature, and low-pressure radical induced oxidation (RIO) technology, so that high-quality ultrathin silicon dioxide layers have been effectively produced with a high reproducibility, and successfully employed to realize high performace SiGe heterostructure complementary MOSFETs (HCMOS) lot the first time. The obtained oxide layer showed comparable leakage and breakdown properties to conventional furnace gate oxides, and no hysteresis was observed during high-frequency capacitance-voltage characterization. Strained SiGe HCMOS transistors with a 2.5 nm-thick gate oxide layer grown by this method exhibited excellent device properties. These suggest that the present technique is particularly suitable for HCMOS devices requiring a fast and high-precision gate oxidation process with a low thermal budget.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1120-1122
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• 2000

Switched Reluctance Motors(SRM) attract much attention in motor because they are reliable and inexpensive. With advance in power electronics and high-speed processors, the performance of SRM has been enhanced greatly But because of its geometric and magnetic structure, the switched reluctance motor naturally creates torque ripples during the commutations of the currents from a supplied phase to an other one. This paper presents the torque ripple reduction using hysteresis current control among of current control techniques.

• Earthquakes and Structures
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• v.7 no.5
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• pp.877-890
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• 2014

The purpose of this study is to present adequate modeling solutions for squat and slender RC walls. ASCE41-13 (American Society of Civil Engineers) specifies that the aspect ratios of height to width for the RC walls affect the hysteresis response. Thus, this study performed non-linear analysis subjected to cyclic loading using two different macroscopic models: one of macroscopic models represents flexural failure of RC walls (Shear Wall Element model) and the other (General Wall Element model) reflects diagonal shear failure occurring in the web of RC walls. These analytical results were compared to previous experimental studies for a slender wall (> aspect ratio of 3.0) and a squat wall (= aspect ratio of 1.0). For the slender wall, the difference between the two macroscopic models was negligible, but the squat wall was significantly affected by parameters for shear behavior in the modeling method. For accurate performance evaluation of RC buildings with squat walls, it would be reasonable to use macroscopic models that give consideration to diagonal shear.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.9-12
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• 1997

The fabrication and performance of a thin film pressure sensor are described. Cu-Ni thin film strain gauges have been fabricated by RF magnetron sputtering. For all the gauges, the relative chance in resistance ΔR/R with pressure is of the order 10$^{-3}$ for the maximum pressure. The output characteristic is found to be linear over the entire Pressure range (0-30kgf/cm$^2$) and the output sensitivity is 1.6 mV/V. The maximum nonlinearity observed in output characteristics is 0.34%FS for 5V excitation and the hysteresis is less than 0.1%FS.