• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.6
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• pp.1136-1141
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• 2016

IoT technology has been used as a core technology of convergence service that needs intelligent information processing, and the importance is largely emerging now. And internal network construction thru IoT interaction device can connect with IoT device effectively, provide diverse services by connection with open platform. Especially, beacon that is based on low electric power bluetooth device is receiving attention as one of core technology of IoT. Beacon technology is utilized widly in various fields of industry, and there are lot of demands in the specific environment and conditions beyond the basic function. On this thesis, the authors are proposing the beacon device that utilized acceleration sensor and hole sensor. this beacon device can control the target on specific situation thru sensing of moving target. For the more, we will expect to apply to the various type of factory environments like detachable installation, optimized management using sensor.

• Journal of the Korean Society for Railway
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• v.20 no.3
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• pp.311-319
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• 2017

The primary suspension system of a railway vehicle restrains the wheelset and the bogie, which greatly affects the dynamic characteristics of the vehicle depending on the stiffness in each direction. In order to improve the dynamic characteristics, different stiffness in each direction is required. However, designing different stiffness in each direction is difficult in the case of a general suspension device. To address this, in this paper, an optimization technique is applied to design different stiffness in each direction by using a conical rubber spring. The optimization is performed by using target and analysis RMS values. Lastly, the final model is proposed by complementing the shape of the weak part of the model. An actual model is developed and the reliability of the optimization model is proved on the basis of a deviation average of about 7.7% compared to the target stiffness through a static load test. In addition, the stiffness value is applied to a multibody dynamics model to analyze the stability and curve performance. The critical speed of the improved model was 190km/h, which was faster than the maximum speed of 110km/h. In addition, the steering performance is improved by 34% compared with the conventional model.

• Proceedings of the KIPE Conference
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• 2001.07a
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• pp.247-251
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• 2001

Universal motors are mainly used for vacuum cleaner application. There are a lot of researches on SRM that applys home appliance throughout the world. The manufacturing cost of SRM drive makes it hard to expand its application to home appliance. This paper presents Single Phase SRM for the vacuum cleaner that has advantge in cost and performance over conventional universal motor. This paper proposes new power device driving scheme by using SRM switching characteristic. The driving scheme is very simple and inexpensive. Dwell Time Control method is used for the minimum switching loss of power device. The switching frequency of power device is less than 4.5kHz at 45,000rpm. By use of this scheme, power device based on very small switching losses can be used on SRM drive. Also, the biggest problem in single phase SRM is starting, this paper shows a new starting algorithm with two hall sensors, accelerating and running sensors, respectively. Finally, the proposed Single Phase SRM achieves higher efficiency and long life time compared to universal motor. Its life time is more than 1500 hours. Its life time is extended 4 times than that of conventional motor and its suction power is increased $20\%$ at the same volume of conventional universal motor.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1564-1567
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• 2005

Zinc oxide thin films were grown at the t emperature of $100^{\circ}C$ and $150^{\circ}C$ by means of plasma enhanced atomic layer deposition (PEALD) and conventional atomic layer deposition for applying to the transparent thin film transistor (TTFT). The growth rate of $1.9{\AA}/cycle$ with oxygen plasma is similar to that of film grown with water. While the sheet resistivity of ZnO grown with water is 1233 ohm/sq, that of film grown with oxygen plasma was too high to measure with 4 point probe and hall measurement system. The resistivity of the films grown with oxygen plasma estimated to be $10^6$ times larger than that of the films grown with water. The difference of electrical property between two films was caused by the O/Zn atomic ratio. We fabricated ZnO-TFT by means of ALD for the first time and the ZnO channel fabricated with water showed saturation mobility of $0.398cm^2/V{\cdot}s$ with bottom gate configuration.

• Proceedings of the KIEE Conference
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• 2002.07b
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• pp.669-672
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• 2002

Establishment of the Quantum Hall Resistance(QHR) Standard as national resistance standard using a room temperature DCC resistance bridge is described. A simple method are used to obtain the current dependence and error of 10: 1 ratio of the bridge instead of the method using a cryogenic resistance bridge. Measurement uncertainty of the system is estimated as $0.14{\times}10^{-6}$ and it is confirmed that the QHR standard is agreed well with the QHR of other NMIs using the cryogenic resistance bridge within the uncertainty, More improvement about performance of the QHR device and 10: 1 ratio accuracy is still under progress.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1146-1151
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• 2003

Pneumatic servo valve is an electro-mechanical device which change electric signals to a proper pneumatic signals, that is, flowrate and pressure. In this study, a pneumatic servo valve was designed and each simulation was conducted on any variation in the flowrate depending upon the magnetic force of the linear force motor and the displacement of the spool. And permanent magnet was used as a material for the plunger of the servo valve. Thereby, a low electrical power consumption type coil was desinged. And a modeling for the coil design was conducted by using the magnetic circuit. also, the feasibility of the modeling was verified by using a commercial magnetic field analysis program. The designed and fabrication of the spool and sleeve, position sensor, servo controller and the dynamic characteristic verified by the experiment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.11a
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• pp.207-207
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• 2006

We investigated the effects of hydrogen addition to the growth process of SiC single crystal using sublimation physical vapor transport(PVT) techniques. Hydrogen was periodically added to an inert gas for the growth ambient during the SiC bulk growth Grown 2"-SiC single crystals were proven to be the polytype of 6H-SiC and carrier concentration levels of about $10^{17}/cm^3$ was determined from Hall measurements. As compared to the characteristics of SiC crystal grown without using hydrogen addition, the SiC crystal without definitely exhibited lower carrier concentration and lower microplpe density as well as reduced growth rate.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11a
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• pp.260-263
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• 2004

During the last few years, there have been many efforts on the fabrication of electronic and optical devices based on semiconductor nanowires. Room-temperature ultraviolet lasing in GaN nanowire, ultraviolet light sensing in ZnO nanowire, and dramatically improved hall mobility in Si nanowire have been demonstrated in this article. The studies on semiconductor nanowire based electronic and optical device is reviewed.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.05a
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• pp.260-261
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• 2017

The objective of this study is to propose the basic design plan of system by comparing and analyzing application environment of lift and elevator group control system, as preliminary study for the application of group control system to lifts for high-rise construction. The basic design plan is suggested in terms of group control algorithm, hall call system type, operation information recording device, information communication method, and operation method. The results of this study can be used as basic data for software and hardware design for application of group control technology of lifts for super tall building construction and ultimately contribute to improve the operation efficiency of lift for high-rise construction.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.11a
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• pp.370-374
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• 2002

Many compound semiconductors which have high carrier mobility and small band gap have attentive in application of various practical a field. Especially, InSb served for Hall device and magnetic resistor such as magnetic sensor because InSb thin film has high mobility. Many studies on InSb thin film deposistion because In and Sb has been very different feature of vapor pressure ($10^{-4}$ times) When In and Sb deposited. In this paper studied it In and Sb deposited simultaneously using by method of co-sputtering deposotion. This process, get to effects of manufacture process simplification. After that this paper observed micro structure and electronic behavior of InSb thin film using by co-sputtering and we study properties of magneto-resistance by annealing.