• 한국항공운항학회지
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• 제31권4호
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• pp.19-27
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• 2023

In this study, a total of 2,584 domestic research papers with the keywords "Aviation Safety" and "Aviation Accidents" were subjected to Text Mining analysis. Various text mining techniques, including keyword frequency analysis, word correlation analysis, network analysis, and topic modeling, were applied to examine the research trends in the field of aviation safety. The results revealed a significant increase in research using the keyword "Aviation Safety" since 2015, with over 300 papers published annually. Through keyword frequency analysis, it was observed that "Aircraft" was the most frequently mentioned term, followed by "Drones" and "Unmanned Aircraft." Phi coefficients were calculated for words closely related to "Aircraft," "Aviation," "Drones," and "Safety." Furthermore, topic modeling was employed to identify 12 distinct topics in the field of aviation safety and aviation accidents, allowing for an in-depth exploration of research trends.

• 한국항공운항학회지
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• 제18권3호
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• pp.34-41
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• 2010

'Aviation Safety' is the state in which the risk of harm to persons or of property damage is reduced to, and maintained at or below, an acceptable level through a continuing process of hazard identification and risk management in the aviation field. 'Risk' is the assessed potential for adverse consequences resulting from a hazard and 'Risk assessment' involves consideration of both the frequency and the severity of any adverse consequence. This study focused on the risk frequency about a case airport which does not meet the 'Runway end safety area' requirement of ICAO SARPs and Korea standards and used 'RSA risk model' for estimating the risk frequency. As results of this study, risk frequency of the runway end safety areas in the case airport is higher than that of 'Runway end safety area' requirement of ICAO SARPs and Korea standards, which means that alternatives for risk frequency mitigation to a level as low as reasonably practicable is required in the case airport. The optimum solution analysed from this study is to impose restriction of aircraft operation when the runway condition is poor(icing condition) and also it snows in the case airport.

• Journal of Power Electronics
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• 제19권5호
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• pp.1133-1141
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• 2019

In this paper, a capacitors energy strategy based Cascaded H-bridge Converter (CHBC) for steady DC link voltage is proposed, which allow the CHBC to work while DC power fails. The topology of the CHBC is analyzed to construct the proposed strategy. The capacitors energy strategy is deduced based on the principle that the DC link voltage should be steady, the switch state should be smooth and the switch frequency should be normal. Experiments based on a three-module prototype, including static experiment, start experiment and step change experiment, proves the correctness of the strategy. They also verified the excellent fault tolerance ability and good dynamic performance of the proposed strategy.

• 한국항공운항학회지
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• 제23권3호
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• pp.94-104
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• 2015

Recently the departments of aviation-related in the college are increased as the aviation industry is rapidly expanded. To enhance their competitiveness and have differentiation, it is emphasized for each department to manage and teach their students well. Therefore this study aims to examine self-efficacy and academic adjustment of aviation-related college students and investigate the relationship between self-efficacy and academic adjustment. To achieve the objectives, it conducted a survey of aviation-related college students in C university from Apr. 27th. 2015 to May. 22th. 2015. A total of 225 questionnaires were analyzed using SPSS 18.0 statistical package program and frequency analysis, factor analysis, reliability analysis, multiple regression analysis, correlation analysis and one-way ANOVA were conducted. The result released that general self-efficacy was recognized higher at the department of aviation operation than aviation maintenance and aviation service and social self-efficacy was recognized higher at the department of aviation service than aviation maintenance and aviation operation. Also general self-efficacy had an influence on the motivation, application and performance and social self-efficacy affected motivation, performance and academic environment. The implication of these findings would help to manage aviation-related college students, develop their departments and provide the directions for future research.

• 한국항행학회논문지
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• 제2권1호
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• pp.22-33
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• 1998

마그네트론을 이용하는 레이다에서 송신 주파수의 변화를 감지하여 안정된 중간주파수를 발생하기 위해서는 STALO(Stable Local Oscillator)로서 AFC(Automatic Frequency Control)에 의해 출력주파수를 조정할 수 있는 주파수 합성기(Frequency Synthesizer)가 이용된다. 본 논문에서는 8.4GHz~9.7GHz의 X-밴드 주파수 합성기를 단일 루우프 구조의 간접 주파수 합성방식으로 설계하고 제작하였다. 고속 디지털 PLL 칩에 의하여 위상비교를 하고, 저 위상잡음을 구현하기 위한 여파기를 설계하였다. 기준신호와 VCO, 주파수 분주기, 여파기 등의 특성에 따른 단일 루우프 주파수 합성기의 위상잡음 성능을 해석하고, 위상잡음이 최소가 되도록 설계하여 측정치와 비교하였다.

• 한국항공운항학회지
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• 제15권2호
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• pp.1-8
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• 2007

In this research, algorithm and software for the medium frequency signal analysis of DGPS(Differential Global Positioning System) station were developed. Based on new MF(Medium Frequency) algorithm, the software of NDGPS(National DGPS) signal analysis was developed for coverage analysis. Predicted MF propagation data from this software was compared to the measurement data for the verification of a developed MF algorithm. GIS(Geographic Information System) techniques including digital map with elevation data were used because MF propagation is closely related to ground conductivity, mountains, building intensity.

• 한국항행학회논문지
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• 제3권2호
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• pp.120-131
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• 1999

마그네트론을 이용하여 송신 펄스를 발생하는 레이다에서 위상을 측정하기 위해서는 송신주파수의 변화에 대해서도 안정된 중간주파수를 발생할 수 있도록 STALO(Stable Local Oscillator)의 주파수를 조정하여야 한다. 레이다 수신기의 AFC(Automatic Frequency control) 회로는 마그네트론에서 발생하는 송신주파수와 STALO의 국부발진주파수를 비교하여 일정한 중간주파수가 발생하도록 STALO 주파수를 제어한다. 본 논문에서는 안정된 중간주파수를 발생하기 위한 AFC 회로를 설계, 제작하였으며, 주파수 변화를 검출하여 비교하는 아날로그 부분과 STALO에 주파수 제어신호를 공급하는 디지털 부분을 개발하였다.

• 융합보안논문지
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• 제10권4호
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• pp.49-59
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• 2010

최근 전 세계적으로 사용자 수가 급격히 증가하고 있는 스마트폰은 기존의 일반 휴대폰보다 뛰어난 기능 및 인터페이스를 제공하고 있다. 또한 사용자의 편의에 따라 스마트폰의 시스템을 커스터마이징하는 사례가 늘어나고 있어 보안이 취약한 스마트폰의 수는 계속해서 증가하고 있다. 이에 따라, 스마트폰을 대상으로 한 악성코드는 매년 증가하는 추세로 위협이 심화되고 있는 실정이다. 따라서 본 보고서는 스마트폰에 전파를 발생시키는 RF통신 모듈의 시스템 설정값을 변경하는 악성코드를 감염시켜 항공 통신 시스템을 대상으로 한 전파교란 취약점을 제안하고 그에 대한 대응방안에 대해 기술한다.

• 한국항공운항학회지
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• 제24권2호
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• pp.59-67
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• 2016

The checklist currently used for Aviation safety inspection performed by ASIs consists of inspection groups and multiple items, it does not have structured hierarchy system which required to efficiently process aviation safety analysis. On this study, through mapping taxonomy of HFACS onto current checklist to secure structured hierarchy system and present a specification on systematic frequency and severity to perform safety risk assessment of detected hazard.

• 한국항행학회논문지
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• 제4권1호
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• pp.36-44
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• 2000

본 논문에서는 디지털 필터를 이용하여 대역통과 신호를 기저대역에서 복원하는 것이 가능함을 보이고 있다. 2차 대역통과 샘플링은 l차 대역통과 샘플링에 비해 보다 용이하게 구현할 수 있으며, 시뮬레이션을 통해 임의 대역으로의 주파수 천이가 가능함을 보였다. 이미 잘 알려져 있는 직교샘플링 방법은 2차 대역통과 샘플링의 특별한 경우인데, 2차 대역통과 샘플링을 적용하여 NCO (Numerical Controlled Oscillator)와 mixer가 제거된 직교복조시스템을 구현할 수가 있다. 이 방식은 기존의 직교복조시스템에 비해 구현이 용이하고 I, Q채널간 매칭정확도가 우수하여 근래의 고성능 레이다나 통신기기에 응용 가능하다. 또한 시뮬레이션을 통해 이미지 성분의 제거가 가능함을 보였다.