• 한국항공운항학회지
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• 제14권4호
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• pp.87-93
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• 2006

The black-tailed gull chicks, Larus crassirostris, recognize various adult voice signal base on the simple patterns. We investigated behavior change in black-tailed gull chicks through physical manipulation of mew call. They were playback in four situations differing in physical character: 1) frequency manipulation only, 2) duration manipulation only, 3) call intensity(dB) manipulation only, and 4) call interval manipulation only. We observed occurrence of different response of the chicks, which were categorized into two behaviors(hidden and return behavior). The manipulated frequency, duration, and intensity were directly correlated. The chicks exposed to only manipulated call interval(0.5, 1sec) made significantly more hidden and return behavior. Adult black-tailed gull only increased flight time on manipulated call interval. The results suggest that black-tailed gulls use short call interval for alarm signal. The analysis of alarm signal provides an important on basic study of bird strike.

• 한국항공운항학회지
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• 제14권2호
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• pp.39-44
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• 2006

The unsteady vortex lattice method is used to model lead-lag in flapping motions of a rectangular flat plate wing. The results for plunging and pitching motions were compared with the limited experimental results available and other numerical methods. They show that the method is capable of simulating many of the features of complex flapping flight. The lift, thrust and propulsive efficiency of a rectangular flat plate wing have been calculated for various lead-lag motion and reduced frequency with an amplitude of flapping angle(20o). To describe a motion profile of wing tip such as elliptic, line and circle, the phase difference of flapping and lead-lag motion was changed. And the effects of the motion profile on the aerodynamic characteristics of the flapping wing are discussed by examination of their trends.

• 한국항공운항학회:학술대회논문집
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• 한국항공운항학회 2004년도 추계학술발표대회 논문집
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• pp.112-115
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• 2004

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.439-442
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• 2005

An airborne radar performance can be sensitive to the variation of the Doppler center frequency and the spectral spread of the ground clutter return due to the radar platform moving and aspect angle of the scanning beam to the target. In this paper, for the performance test of the airborne pulsed Doppler radar system developed, the high-speed radar data acquisition system is implemented for acquiring the raw radar signal in real-time. Based on the various test scenarios from airborne-platform to the moving platform, the various radar target and clutter signals are collected and their spectrum is analyzed for the verification of the radar performance in the real-time flight test environments.

• 유통과학연구
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• 제18권10호
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• pp.39-52
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• 2020

Purpose: This study aims to find out the relationship between the impact of Korean crew on airline service quality in the global aviation market, which is the representative of the face-to-face sales and can help in the face-to-face market of aviation services. Research design, data: The survey was conducted for about a month from March 1 to April 6, 2020, and a total of 300 copies were used in the analysis of the results. To verify the hypothesis, data was analyzed using the statistical package program SPSS 18.0, and frequency analysis, exploratory factor analysis, correlation analysis, and multiple regression analysis were performed. Results: It is a study on the sales of face-to-face service of crews of global airlines. Non-verbal elements in airline service face-to-face sales have been shown to have a significant impact on service quality. Conclusions: In the face-to-face service sales of global airlines, communication has been shown to affect service quality. A face-to-face sale using mother tongue means important. The better the flight attendant's linguistic face-to-face selling ability, the more positive on the airline's quality of service. It suggests that the communication skills of managers in the aviation service market are important for repurchase.

• 한국기계가공학회지
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• 제21권1호
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• pp.73-80
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• 2022

Sensors are applied to small aviation platforms for various purposes. Radio frequency (RF) antennas, which are representative sensors, are available in many forms but require the application of slot array RF antennas to ensure high performance and designation. Slot RF array antennas are applied to dip brazing techniques, but the yield and production time are determined by the proficiency of production personnel in a labor-intensive form. Unmanned aerial vehicles or drones, which are representative small aviation platforms, are continuously exposed to various random vibrations because propellers and multiple power sources are used in them. In this study, the fatigue life of slot array RF antennas applied with additive manufacturing was evaluated through the cumulative damage method (Miner's rule) in a vibration environment with a small aviation platform. For the evaluation, an S N curve obtained from a fatigue strength test was used.

• 한국항행학회논문지
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• 제4권2호
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• pp.171-181
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• 2000

본 논문에서는 DSRC(Dedicated Short Range Communication) 시스템을 이용하여 이동하는 차량에 탑재된 단말장치(OBE : On-Board Equipment)와 도로변에 설치된 기지국 장치 (RSE : Road-Side Equipment) 사이에 5.8GHz대 ISM대역의 주파수를 사용한 무선패킷통신방식을 통한 차량위치 추적 시스템을 제안한다. 기존의 차량 위치 추적 방식은 차량위치를 파악하여 차량위치를 센터와 사용자에게 전송하는 무선 통신방식으로 단순한 센서만 사용되었지만, 본 시스템은 차량의 위치, 통관, 차량간 통신, 교통정보 수집 및 분배 등의 다양한 업무를 수행하도록 개발되었다. 또한, 빠른 처리를 위해 통신 계층 중 물리, 데이터링크, 응용계층으로 설계하여, 기존의 무선 통신방식 및 센서를 대체할 새로운 기술로 제안한다.

• 한국항행학회논문지
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• 제15권5호
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• pp.714-721
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• 2011

본 논문에서는 전자파방해(EMI) 발생 위치 추적을 위한 관리프로그램을 개발하여 전자파방해(EMI) 발생시 현장을 신속하게 탐색할 수 있으며, 또한 전자파방해(EMI)로 인한 항공기 사고 관련 분석 자료와 전자파방해(EMI)발생 현장인 1000개의 RF 업체 위치자료와 전파환경 스펙트럼 분석 및 오디오 자료등을 데이터베이스화 하여 비교자료로 활용하므로써 신속한 원인분석과 정확한 위치 추적으로 전자파방해(EMI)를 일소할 수 있게 되었고, 또한 상시 모니터링 시스템을 구축하여 24시간 감시를 통하여 전자파방해(EMI) 발생을 예방하고 있다. 따라서 항공기 사고 방지를 위하여 양질의 항공전파를 제공할 수 있었다. 또한 항공기 탑승객을 상대로 정기적으로 항공주파수 보호 및 항공기 기내 전자 기기(PED) 사용으로 인한 야기 될수 있는 전자파방해(EMI)방지 안전문화 캠페인를 펼쳐 항공주파수를 안전하게 보호할 수 있었고, 또한 최악의 항공기 사고를 예방할 수 있는 기반을 마련 할 수 있었다.

• 한국산업정보학회논문지
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• 제22권1호
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• pp.41-51
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• 2017

This Paper Describes a Method for the Evaluation of Sleep Apnea, Namely, the Peak Signal-to-noise ratio (PSNR) of Wavelet Transformed Electroencephalography (EEG) Data. The Purpose of this Study was to Investigate EEG Properties with Regard to Differences between Sleep Spindles and K-complexes and to Characterize Obstructive Sleep Apnea According to Sleep Stage. We Examined Non-REM and REM Sleep in 20 Patients with OSA and Established a New Approach for Detecting Sleep Apnea Base on EEG Frequency Changes According to Sleep Stage During Sleep Apnea Events. For Frequency Bands Corresponding to A3 Decomposition with a Sampling Applied to the KC and the Sleep Spindle Signal. In this Paper, the KC and Sleep Spindle are Ccalculated using MSE and PSNR for 4 Types of Mother Wavelets. Wavelet Transform Coefficients Were Obtained Around Sleep Spindles in Order to Identify the Frequency Information that Changed During Obstructive Sleep Apnea. We also Investigated Whether Quantification Analysis of EEG During Sleep Apnea is Valuable for Analyzing Sleep Spindles and The K-complexes in Patients. First, Decomposition of the EEG Signal from Feature Data was Carried out using 4 Different Types of Wavelets, Namely, Daubechies 3, Symlet 4, Biorthogonal 2.8, and Coiflet 3. We Compared the PSNR Accuracy for Each Wavelet Function and Found that Mother Wavelets Daubechies 3 and Biorthogonal 2.8 Surpassed the other Wavelet Functions in Performance. We have Attempted to Improve the Computing Efficiency as it Selects the most Suitable Wavelet Function that can be used for Sleep Spindle, K-complex Signal Processing Efficiently and Accurate Decision with Lesser Computational Time.

• 한국항공운항학회지
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• 제25권3호
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• pp.74-80
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• 2017

As for A rotary wing aircraft, the configuration change about split yaw swaged rod was executed to improve hit treat capability for dealing with a long rod. The purpose of this study was to analyze if or not the quality of the split yaw swaged rod was obtained, and so the flight safety was ensured or not. Buckling analysis, Coupling Thread Strength Analysis, Thermal Stress analysis and Rod Natural Frequency Analysis were executed for structural analysis. The results of the analysis were presented that the split rod had the sufficient margin of safety and so there were no anomalies in the limit load and no failures in the ultimate load. And there were no resonances in result of natural frequency analysis. In conclusion, this study showed that the split yaw swaged rod had structural safety, so flight safety of rotary wing aircraft was secured and there was no problem in aircraft operation. It is certain that the technology of splitting the yaw swage rod will contribute to the operational Safety of the rotary wing aircraft in the future.