• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.3
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• pp.697-707
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• 2015

This paper covered the design and implementation of the demodulation receiver in the ADS-B 1090ES system, which is one of the CNS/ATM's surveillance systems. This researched demodulation performed at the level required by RTCA DO-268B and EUROCAE ED-129. The single signal process method, which applies a baseline multi-sample technique among multi-amplitude sample demodulations, was suggested to improve the quality of the receiver signal, the dynamic range and so on. The suggested multi-signal level tuning method has enhanced the single-signal process method, reducing the unstable reception ratio by the transmit output level difference and manufacturing receiver hardware. The result was that the receiver suggested by the method had 0~87dBm in dynamic range and -90dBm in MTL. This shows a better performance by -3dBm less than the international standard in ADS-B 1090ES ground receiver equipment. The systems which use a similar modulation method, will be considered to be widely applied.

• Journal of The Korean Association For Science Education
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• v.43 no.6
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• pp.573-582
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• 2023

This study aimed to explore the potential use of artificial intelligence in science education for gifted students by analyzing the structure of abstracts written by students at a gifted science academy and comparing the performance of various elements extracted using AI. The study involved an analysis of 263 graduation theses from S Science High School over five years (2017-2021), focusing on the frequency and types of background, objectives, methods, results, and discussions included in their abstracts. This was followed by an evaluation of their accuracy using AI classification methods with fine-tuning and prompts. The results revealed that the frequency of elements in the abstracts written by gifted students followed the order of objectives, methods, results, background, and discussions. However, only 57.4% of the abstracts contained all the essential elements, such as objectives, methods, and results. Among these elements, fine-tuned AI classification showed the highest accuracy, with background, objectives, and results demonstrating relatively high performance, while methods and discussions were often inaccurately classified. These findings suggest the need for a more effective use of AI, through providing a better distribution of elements or appropriate datasets for training. Educational implications of these findings were also discussed.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2001.04a
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• pp.81-81
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• 2001

초지 공정은 wire, roll, pump등의 회전체로 이루어진 공정이 거의 대부분이기 때문에 주기적으로 변동하는 성분들이 많고, QCS(Quality Control System) 및 DCS(Distributed Co n ntrol System)상에 서 의 자동 Control Logic에 의 한 불안정 (Fluctuation)요소도 내 재 되 어 있 어 이에 대한 분석이 필요하다. 이러한 주기적인 변동은 제품의 여러 물성(평량, 두께, 광택 도등) 에 영향을 미치게 되어 품질의 균일성이나 프로파일에 영향을 미치게 된다. 따라서 공정상이나 품질에서 주기적으로 변동하는 성분을 추출하여 공정 각 성분과 연관을 시키변 품질에 나타나는 주기적 성분의 요인이 어느 부분에서 기인하는 지를 직접적으로 찾아낼 수 있고 이의 개선을 통해 품질의 균일성 및 프로파일 향상을 꾀할 수 있다. 본 연구에서는 Air padded type 헤드박스 초지기에서 DAQ(Data Acquisition) System 을 이용하여 각 공정별로 MD(Machine Direction)방향으로의 변동을 측정하고 제품의 물성 변동과 비교하였다. DAQ System은 각 공정상의 전기적 신호를 높은 주파수 영역까지 다채널로 동시에 받 아 들일 수 있는 장치로 이 시스템을 활용하여 공정상의 Machine chest 농도, Stock box 유량 및 레벨, Fan pump RPM, Cleaner압력, Screen압력, H!B압력 및 레벨, Silo level등 공 정요소의 변동상태와 상호영향을 분석하였다. 이러한 공정 각 요소의 변동과 MD 방향의 제품 물성 값(Tapio, Paper Variation Analyzer에 대한 비교 분석결과 제품 평량에서 주기적인 변동성분을 확인할 수 있었고 이중 큰 비 중을 차지하는 것이 fνB 레벨 변동주기와 일치하는 것을 찾아낼 수 있었다. 이에 근거하여 D DCS system의 control 요소인 튜닝 parameter(P,I 값)들을 미 세 조정 하여 제 품의 MD방향 평량 변동 진폭을 기존 수준의 30% 수준으로 감소시킬 수 있었다. 그 결과 COV(표준편차/ 평량)값을 0.8-1.2%에서 0.6-0.8%수준으로 낮출 수 있었고 이에 따라 CD (Cross Direction) 방향의 제품 Profile도 함께 개선되는 효과를 거둘 수 있었다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.189-192
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• 2014

Recently, U.S. and Europe, which are advanced to Air Traffic Control Management, are interest in replacing Radar System with Communications, Navigation and Surveillance(CNS) and Air Traffic Management(ATM). They pursue to research the efficient Air Traffic Control Management. This paper covers ADS-B 1090ES system which is one of CNS/ATM surveillance systems. This research satisfied all performance required by RTCA DO-268B and EUROCAE ED-129. It optimized algorism to mainly enhance performance such as quality of receiver signal, dynamic range, and so on. The optimized mechanism provided stable performance of demodulation, tuned the level of signal, and had reduced the false reception ratio by the signal level difference. The analyzed algorism helped great performance and will be considered to apply broad system applications.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.3
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• pp.219-232
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• 2013

This paper presents a microstrip antenna which recovers its resonant frequency and impedance shifted automatically by the approach of other objects such as hands. This can be used for telemetry sensor applications in the ultrahigh frequency(UHF) industrial, scientific, and medical(ISM) band. It is the key element that an frequency-reconfigurable antenna could be electrically controlled. This antenna is miniaturized by loading the folded plates at both radiating edges, and varactor diodes are installed between the radiating edges and the ground plane to control the resonant frequency by adjusting the DC bias asymmetrically. Using this voltage-controlled antenna and the micro controller peripheral circuits of reading the returned level, the antenna is designed and fabricated which recovers its resonant frequency and impedance automatically. Designed frequency auto recovering antenna is conformed to be recovered within a few seconds when the resonant frequency and impedance are shifted by the approach of other objects such as hand, metal plate, dielectric and so on.