• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.6
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• pp.484-491
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• 2016

The purpose of this development is weight reduction of hollow type steel torque bar by changing the material from steel to composite. Structure analysis is executed by the finite element model generated by the structural load condition and geometric structure requirement. According to this analysis result, optimized ply sequence and wall thickness are defined. To simulate analysis result, torsion test for composite torque bar was performed. Throughout the test result, the stiffness and strength requirement of composite torque bar was verified.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.10
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• pp.1061-1070
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• 2002

In this paper, we present a performance analysis of the smart antenna test-bed operating in a IS2000 1x through a test-bed that has been implemented on a DSP(TMS320C6711) board. The test-bed consists of a PC (for generating the RX data), beam-former(i.e., a stand-alone PCB for weight computation), and an interfacing module. The performance improvements compared to a normal base station system consisting of a single antenna are shown in terms the BER(bit error rate) in the wide-band CDMA channel.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.3 s.106
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• pp.295-306
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• 2006

In this paper, we proposed and implemented a novel antenna cover mounted over a microstrip path antenna for ultrafast aircraft. A protective antenna cover prevents alteration in the electrical characteristics of the antenna due to environmental conditions. The permittivity of the cover materials should be practically invariable at all operating frequencies. We evaluated the characteristics of the antenna with both simulation and experiment. The experimental results show that the proposed antenna cover can be useful for ultrafast aircraft.

• Journal of Digital Convergence
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• v.12 no.11
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• pp.349-355
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• 2014

In this paper, we propose the artificial vision system using human visual information processing and wavelet. Artificial vision system may be used for the visually impaired person and the machine recognition system. In this paper, we have constructed the information compression process to ganglion cells from the human retina. And we have reconstructed the primary visual information using recovery process to primary visual cortex from ganglion. Primary visual information is constructed by wavelet transformation using a high frequency and low frequency response. In the experiment, we used the faces database of AT&T. And the proposed method was able to improve the accuracy of face recognition considerably. And it was verified through experiments.

• 연구논문집
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• s.28
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• pp.229-238
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• 1998

Materials and parts required for nondestructive testing should be evaluated using with standard block. And it is ruled that standard blocks should be fabricated from same or similar material with test specimen. In order to manufacture and export materials and parts, quality assurance system should be required. In this paper, ultrasonic characteristics of ASTM 4340 steel ultrasonic standard block are investigated for nondestructive evaluation of udimet 720Li disc. Microstructures of udimet 720Li alloy are investigated using with optical and transmission electron microscope. Also ultrasonic transit time and attenuation are measured from high power ultrasonic analysis system with phase adjustment method. Conclusively, it is proved that 4340 steel ultrasonic standard block can be use for nondestructive evaluation of udimet 720Li disc.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.188-193
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• 2017

USA and Europe are leading a transport airplane industry. In Asia-Pacific region, air transportation and MRO industries are forecasted to be grown up rapidly. Furthermore, Japan and China entered into design and manufacture state of regional airplane, and developing countries entered into severe struggle competition for MRO industry. Global aircraft MRO and engine MRO industries are forecasted 3.4% and 7% growth respectively in next decade. In this paper, authors propose promotion strategy for technology intensive MRO of aircraft engine to create a higher value-added business.

• Journal of Satellite, Information and Communications
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• v.1 no.1
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• pp.54-58
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• 2006

A new design for easily controlling operating frequency of an antenna-integrated planar oscillator is introduced. The oscillator circuit of a broadband negative-resistance active part and a passive load including a patch antenna. The patch resonance is used for determining the oscillation frequency. This design reduces the possibility of mismatch between antenna radiation and oscillation frequencies. To achieve optimum output power, load-pull simulation for the negative-resistance circuit is used. The load-pull simulation shows the feed point and the delay of feed line can affect the oscillation power. Two negative-resistance circuits capable of supporting oscillation over full C-band and X-band are fabricated. The oscillation frequency, output power and phase noise for different patch antennas are measured.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.6
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• pp.14-21
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• 2004

This automotive headlight control system is newly proposed that, under my slope degree of the driving mad(flat up-hill, and down-hill) at night driving, the reflecting mirror of the headlight can be automatically controlled for safe driving. At first whether or not any vehicle is driven near is checked by photo sensor. Secondly, using the slope degree of the automotive feedbacked from the tilt sensor, the servo motor with the headlight is controlled to be turned right or down to the suitable angle. The servo motor is appropriately controlled according to road conditions. The proposed headlight control system is designed on the basis of the tested illumination intensity obtained according to any slope degree of roads. Finally, it is confirmed that the test model works very well in the given road conditions and environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.825-834
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• 2000

In this paper, we have designed a bandpass filter with via-holes ground on K-band To pass only the 25 ~30% of the bandwidth at the center frequency of 19.6GHz, we have designed a six-order interdigital bandpass filter using microstrip lines. Simulation results of optimization according to via-holes size and numbers of interdigit bandpass filter shows a excellent agreement with theoretical values on passband frequency. Experimental results of BP filters show that mesaured center frequency is 19.150Hz, insertion loss, -4.1dB, reflection coefficient, -16.7dB. It proved that the vis-holes ground size and numbers must be considered to design the bandpass filter.

• Proceedings of the Korea Information Processing Society Conference
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• 2014.11a
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• pp.346-348
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• 2014

본 시스템은 스마트폰 어플리케이션과 아두이노 보드, 웹서버로 구성된 시스템으로서, 학생들이 보다 편리하게 교내 건물에 출입 할 수 있게 하기 위해서 개발하였다. 학생들이 플라스틱 카드로 만들어진 학생증 없이도 스마트폰 어플리케이션으로, 교내 건물에 출입 할 수 있는 기능을 제공함으로써 많은 플라스틱 카드를 대체할 것으로 생각된다. 이를 통해 플라스틱 카드를 따로 가지고 다니지 않아도 되는 편의성을 제공하며 학생증 분실 위험도 막을 수 있다. 또한 플라스틱 카드 제작을 줄여 친환경의 Green IT를 실현할 수 있다. 학생인증 방법은 스마트폰 어플리케이션에서 종합정보시스템 상의 학번과 비밀번호를 입력하면 서버에서 일치 여부를 확인하여 로그인 승인을 해준다. 이후 블루투스 통신을 통해 아두이노 보드에 출입 요청을 보내면 아두이노 보드에 연결된 모터로 문을 개폐한다. 이외에 학생증의 본래 기능인 학생 증명 기능과 학생증으로 이용할 수 있는 제휴업체의 정보도 제공한다.