• International Journal of Aerospace System Engineering
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• 제10권1호
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• pp.14-24
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• 2023

The materials applied to the aircraft fuselage, parts, and components must be verified by relative authorities in accordance with the procedures set by the airworthiness authority to achieve the aircraft type certification. There are no examples of domestic composite materials which were verified in order to be applied to aircraft structure. In this study, the composite material certification system of NCAMP, an American composite material standard certification organization, was reviewed and used as the fundamentals of the first aerospace composite material certification system in ROK(Fig 2,8). Also updated material certification documents were developed and confirmed by material certification engineers and inspectors. This aerospace composite material qualification system is intended to modernize the material certification system for AAM(Advanced Air Mobility) as well as aircraft and to enhance the understanding of related technicians and inspectors.

• Journal of Mechanical Science and Technology
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• 제20권5호
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• pp.668-674
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• 2006

In order to develop a cell based robot, we present a micro-mechanical force measurement system for the biological muscle actuators, which utilize glucose as a power source. The proposed measurement system is composed of a micro-manipulator, a force transducer with a glass probe, a signal processor, an inverted microscope and video recording system. Using this measurement system, the contractile force and frequency of the cardiac myocytes were measured in real time and the magnitudes of the contractile force of each cardiac myocyte under different conditions were compared. From the quantitative experimental results, we could estimate that the force of cardiac myocytes is about $20\sim40{\mu}N$, and show that there are differences between the control cells and the micro-patterned cells.

• 항공우주시스템공학회지
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• 제15권4호
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• pp.30-39
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• 2021

This paper presents a study on the design and structural substantiation of the interior structure of the new VVIP aircraft. In this study, the structural design and analysis of the compartment with aluminum alloy and sandwich composite panel were performed. The structural design requirements from the Federal Aviation Administration were identified. The structural analysis of the compartment was performed by the utilization of the finite element analysis method, for the structural design process. Therefore, the designed cabin compartment secured the structural integrity, and satisfied its certification standards and design requirements via structural analysis.

• 경영정보학연구
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• 제24권2호
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• pp.21-40
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• 2022

본 연구는 인천국제공항 중심 경제권 형성을 통한 허브 경쟁력 확보를 위해 향후 인천국제공항이 중점적으로 고려 및 개선해야 하는 요인을 도출하는 것을 목적으로 한다. 이를 위해 세계적 수준의 환승 공항을 이용한 승객이 작성한 온라인 리뷰를 대상으로 텍스트 분석을 실시하여, 승객이 중요하게 인식하는 환경요인을 도출하였다. 이후, 구체적인 인식 조사를 위해 도출된 환경 요인 중 15개의 세부평가 요인을 선행 연구에 기반하여 선정하였다. 해당 요인들은 전문가를 대상으로 중요도와 수행도를 확인하고자 설문조사 및 IPA 분석을 수행하였다. 분석 결과, 모든 요인에 있어, 중요도보다 수행도가 낮은 것으로 평가되었으며, 향후 인천국제공항이 중점적으로 개선해야 하는 상위 3개 요인으로 접근시설(편의성 및 다양성, 비용, 시간), 경제자유지역, 다양하고 우수한 쇼핑시설이 제시되었다. 본 연구는 텍스트 분석과 설문조사의 장점을 복합적으로 활용하여 승객의 인식을 이해했다는 점에서 의의가 있다. 본 연구 결과는 향후 허브 공항의 입지를 확고히 하기 위한 정책적, 전략적 방향성 수립에 활용될 수 있다.

• 한국ITS학회 논문지
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• 제12권6호
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• pp.44-53
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• 2013

미국, 유럽 선진국들을 중심으로 진행 중인 SWIM(System Wide Information Management)은 국제민간항공기구(ICAO)에서 항공관련 데이터 시스템의 성능을 향상시키는 ASBU(Aviation System Block Upgrade) 프로그램의 일부분이며, 디지털 항공 정보 관리를 통해 서비스를 향상시키기 위한 항공통신 데이터를 종합 관리하는 망의 핵심적인 기술이다. 이에 따라, 본 논문에서는 SOA(Service Oriented Architecture) 개념을 적용한 SWIM 구조와 네트워크를 분석하고, 기존의 레거시 시스템으로 운용중인 애플리케이션을 어댑터 기술 개발을 통하여 항공데이터 종합관리망으로 구축하는 방안을 제안한다. 제안한 방안은 효율적인 ATM(Air Traffic Management)을 위한 차세대 인프라 망 환경에 적합한 미들웨어 및 애플리케이션 개발로 사용자가 원하는 정보를 적시에 제공할 것이다.

• 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.

• The Journal of Asian Finance, Economics and Business
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• 제7권8호
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• pp.333-344
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• 2020

This research has four specific objectives: (1) identifying factors that affect customer satisfaction with less than container load (LCL) cargo services of logistics companies in HoChiMinh City (HCMC), (2) measuring the level of impact of the factors, (3) testing the difference in satisfaction among groups of customers with different characteristics in terms of type of business and time of using LCL cargo services, and (4) proposing some management implications to improve the quality of LCL cargo services. Researchers interviewed 210 customers who enjoyed the LCL cargo service in HCMC for at least the last six months, using the convenient sampling method. SPSS 20 was used to analyze the reliability of the scale through the Cronbach's alpha coefficient, then exploratory factor analysis and multiple linear regression analysis were used. The results identified the six factors that influence positively customer satisfaction of LCL cargo services of logistics companies in HCMC, by decreasing importance: service process, image, resource, price, management, and outcomes. The results show that there is no difference in customer satisfaction with LCL cargo services by types of business as well as time of using services. The research suggests some implications for the management of logistics companies in HCMC to enhance customer satisfaction.

• 한국전자파학회:학술대회논문집
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• 한국전자파학회 2003년도 종합학술발표회 논문집 Vol.13 No.1
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• pp.229-233
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• 2003

In this paper we theoretically analyze the probability of error for M-ary pulse position modulation (PPM) ultra-wideband (UWB) multiple access system using Gaussian monopulse. The optimum detection of UWB signals using M-ary orthogonal PPM in additive white Gaussian noise (AWGN) and multiple access interference (MAI) is considered, then receiver signal to noise power ratio (SNR) and upper bound fur the bit error rate (BER) are derived. Numerical results considering some practical parameters are presented.

• Advances in Computational Design
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• 제4권3호
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• pp.197-210
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• 2019

Motion generation of a four-bar linkage is a type of mechanism synthesis that has a wide range of applications such as a pick-and-place operation in manufacturing. In this research, the use of meta-heuristics for motion generation of a four-bar linkage is demonstrated. Three problems of motion generation were posed as a constrained optimization probably using the weighted sum technique to handle two types of tracking errors. A simple penalty function technique was used to deal with design constraints while three meta-heuristics including differential evolution (DE), self-adaptive differential evolution (JADE) and teaching learning based optimization (TLBO) were employed to solve the problems. Comparative results and the effect of the constraint handling technique are illustrated and discussed.

• 한국항행학회논문지
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• 제14권3호
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• pp.303-312
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• 2010

VHF Omnidirectional Radio range (VOR)은 항행안전시설로 ICAO (International Civil Aviation Organization) 및 국내법규에 의해 1~2개의 고정된 지점에서 모니터용 안테나를 통해 전파의 상태를 감시하도록 하고 있다. 본 논문에서는 수신된 전파의 복조 파형을 이용하여 VOR의 전파를 감시하는 방안을 제안하였다. 제안된 방식은 기존 데이터방식의 단점을 보완하여 약 30%를 차지하는 불감지역이 제거되었고, 측정 지점보다 최대 좌우 20도 범위의 방위각에 대한 전파를 감시할 수 있었다. 시각적 분석을 통해 전반적인 전파패턴 감시 그리고 전파왜곡의 원인이 되는 대략적인 방위각도 일부 예측할 수 있음을 시험을 통해 확인하였다.