• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.4
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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.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.3
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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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• v.19 no.5
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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.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.23 no.3
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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.

• Journal of Advanced Navigation Technology
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• v.2 no.1
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• pp.22-33
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• 1998

In the coherent-on-receiver radar system using the magnetron source, frequency synthesizer is employed as a STALO(Stable Local Oscillator) to keep the intermediate frequency stable. In this paper, X-band(8.4GHz~9.7GHz) single loop frequency synthesizer is designed and implemented by an indirect frequency synthesis technique. Phase comparison is performed by a digital PLL(Phase-Locked Loop) chip and the loop filter is designed for the low phase noise. The effects of loop component characteristics on the output phase noise are analyzed for single loop structures, and the calculated results are compared with the measured data.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.2
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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.

• Journal of Advanced Navigation Technology
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• v.3 no.2
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• pp.120-131
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• 1999

For the phase measurement in the radar system using the magnetron pulse source, the STALO (Stable Local Oscillator) frequency need to be controlled to provide the stable intermediate frequency. In radar receiver, AFC(Automatic Frequency Control) circuit detects the transmitting frequency change and controls the STALO frequency to keep the intermediate frequency stable. In this paper, we designed and implimented AFC circuits for radar receiver. The frequency deviation is detected and compared with the reference frequency and the STALO frequency is controlled by the digital command signal.

• Convergence Security Journal
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• v.10 no.4
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• pp.49-59
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• 2010

Recently, As smart phone offers rather superior functionality and interface than normal phone, the number of user increase rapidly. for the convenience of user, there are so many case of customize the system. Simultaneously a number of smart phones which vulnerable to security increase Exponentially. The number of malware which targets smartphone increases Annually, namely Threats have intensified. In this thesis, we suggest the Techniques and countermeasures of the vulnerability which targets aviation communication system by Smart-phone RF module with frequency modulation.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.24 no.2
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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.

• Journal of Advanced Navigation Technology
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• v.4 no.1
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• pp.36-44
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• 2000

A frequency-shifting technique that uses a digital filter in order to interpolate a bandpass-sampled signal at a low-pass position is investigated. The discussion focuses on the derivation of the required digital filter. It is shown that second-order bandpass sampling offers more flexibility than first-order bandpass sampling in the sense of sampling frequency choice. It is also shown that the well-known quadrature-sampling method for frequency-shifting is a special case of the general second-order sampling technique. The advantages of the mixer-free digital quadrature demodulations are increased flexibility for sampling frequency choice and high precision for I/Q component extraction, and this type of modulation can be applied for modern radar signal processing with high performance.