• International Journal of Advanced Culture Technology
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• 제6권4호
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• pp.190-194
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• 2018

The runway visual range is one of the important factors that decide the possibility of taking offs and landings of the airplane at local airports. The runway visual range is affected by weather conditions like fog, wind, etc. The pilots and aviation related workers check a local weather forecast such as runway visual range for safe flight. However there are several local airfields at which no other forecasting functions are provided due to realistic problems like the deterioration, breakdown, expensive purchasing cost of the measurement equipment. To this end, this study proposes a prediction model of runway visual range for a local airport by applying convolutional neural network that has been most commonly used for image/video recognition, image classification, natural language processing and so on to the prediction of runway visual range. For constituting the prediction model, we use the previous time series data of wind speed, humidity, temperature and runway visibility. This paper shows the usefulness of the proposed prediction model of runway visual range by comparing with the measured data.

• 한국항공우주학회지
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• 제47권4호
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• pp.266-273
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• 2019

다수의 소형 정찰용 무인항공기를 이용하여 탐색 및 정찰 임무를 수행하는데 있어서 무인항공기의 운용 대수, 비행고도 등 운용 조건에 따라 임무 수행의 효율성과 효과성은 크게 변경될 수 있다. 하지만 어떤 운용조건이 가장 합리적인지 판단하기는 쉽지 않다. 따라서 본 연구에서는 자율비행에 따라 충돌을 회피하면서 표적을 탐지 및 판별할 수 있는 무인항공기 비행 시뮬레이션을 개발하여 다수의 무인항공기 운용 시 보다 효과적이고 효율적인 운용조건을 도출할 수 있는 방안을 제시하였다.

• Computers and Concrete
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• 제23권5호
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• pp.361-376
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• 2019

In this research, bending analysis of a micro sandwich skew plate with isotropic core and piezoelectric composite face sheets reinforced by carbon nanotube on the elastic foundations are studied. The classical plate theory (CPT) are used to model micro sandwich skew plate and to apply size dependent effects based on modified strain gradient theory. Eshelby-Mori-Tanaka approach is considered for the effective mechanical properties of the nanocomposite face sheets. The governing equations of equilibrium are derived using minimum principle of total potential energy and then solved by extended Kantorovich method (EKM). The effects of width to thickness ratio and length to width of the sandwich plate, core-to-face sheet thickness ratio, the material length scale parameters, volume fraction of CNT, the angle of skew plate, different boundary conditions and types of cores on the deflection of micro sandwich skew plate are investigated. One of the most important results is the reduction of the deflection by increasing the angle of the micro sandwich skew plate and decreasing the deflection by decreasing the thickness of the structural core. The results of this research can be used in modern construction in the form of reinforced slabs or stiffened plates and also used in construction of bridges, the wing of airplane.

• The Journal of Korean Physical Therapy
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• 제33권2호
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• pp.76-83
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• 2021

Purpose: This study examined the effects of applying the Pilates reformer exercise to 17 adult women on the alignment of the standing posture. Methods: The subjects performed a Pilates reformer exercise for 60 minutes a day, three times a week, for a total of eight weeks. The Pilates reformer exercise consisted of five types: 1) lower and lift, 2) hundred, 3) plow, 4) airplane, and 5) twist. The standing posture alignment in the sagittal and frontal planes was measured using exbody 9100MOMI musculoskeletal analysis equipment. Results: A comparison of before and after the exercise using paired t-test revealed a significant decrease in the difference between the horizontal inclination and the vertical height that approached zero after the intervention in the frontal plane of anterior and posterior standing postures (p<0.05), and the lateral standing posture in the sagittal plane. In addition, the difference between the horizontal inclination and the vertical height decreased and approached zero after the intervention (p<0.05). Conclusion: The Pilates reformer exercise had a positive effect on the alignment of the standing posture.

• Ocean and Polar Research
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• 제42권4호
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• pp.293-301
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• 2020

Blades of tidal stream turbines have to sustain many different loads during operation in the underwater environment, so securing their structural safety is a key issue. In this study, we focused on periodic loads due to wave orbital motion and propose a load reduction method with a blade design. The flap of an airplane wing is a well-known structure designed to increase lift, and it can also change the load distribution on the wing through deflection. For this reason, we adopted a passive flap structure for the load reduction and investigated its effectiveness by an analytical method based on the blade element moment theory. Flap torsional stiffness required for the design of the passive flap can be obtained by calculating the flap moment based on the analytic method. Comparison between a flapped and a fixed blade showed the effect of the flap on load reduction in a high amplitude wave condition.

• 한국항공운항학회지
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• 제30권2호
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• pp.70-77
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• 2022

This study is a study to analyze the stress difference of pilots according to the category of aircraft. According to previous studies, pilot stress is affected by several factors such as flight time, fatigue regulation, and operating environment, and it is known that stress also affects cardiac variability. In this paper, we analyzed that there is a difference in stress according to the operating environment through airline pilots and pilots of educational institutions, and then tested the difference in stress between airplane pilots and helicopter pilots. This study differs in that it is a study that has almost no empirical research on pilot fatigue and stress considering the role of flight crew members and operational conditions for each mission. If we expand and verify the sample of the results for the stress difference in the future, it will be a great contribution to practical aviation safety research in connection with the fatigue risk management system in the future.

• 한국항공운항학회지
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• 제30권3호
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• pp.65-75
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• 2022

This study tried to confirm whether the public's negative emotions such as fear and anxiety about corona virus infection caused by the spatial nature of the aircraft were alleviated due to factors of in-flight services focusing on hygiene and quarantine and further had a positive effect on the formation of Rapport between cabin crews and passengers. We also investigated the impact on passengers' perceptions such as Reliability and Safety which can be viewed as a new measure and standard of customer satisfaction in the Pandemic era through Rapport. A survey was conducted online in December 2021 for passengers with experience in boarding aircraft after the COVID-19 outbreak, and a total of 211 responses were used for analysis. As a result of the analysis of the data, it was confirmed that aircraft in-flight service had a positive (+) effect on Rapport, and Rapport between passengers and cabin crews had a positive (+) effect on passenger Reliability and Safety.

• 한국항공운항학회지
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• 제29권4호
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• pp.96-104
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• 2021

Technological advances have recently led to the development of Urban Air Mobility (UAM) which is a small airplane being able to take off and land vertically. It is emerging as an alternative to transportation services in the city in the future because of the advantage of providing speed and congestion problem in cities like taxis. This research aim to study the user's acceptance of UAM. Based on the survey conducted abroad, the analysis was carried out based on th Technology Acceptance Model (TAM), by Davis et al. (1989). According to the data analysis results of 292 people, Technology, Reliability and Price effect perceived usefulness, which in turn effects Behavioral intention. UAM cannot be operated independently by a single company. It consists of partnerships with vehicles, transport platforms, batteries and other related company. To improve acceptance of UAM, it is required that collaboration between companies and support from government. And while UAM is being developed, research on acceptance from user's point of view should continue.

• 한국항공운항학회지
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• 제31권1호
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• pp.37-42
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• 2023

In an effort to reduce aircraft noise, noise abatement areas are designated and notified, and noise abatement procedures are implemented. However, residents in noise abatement areas are increasingly complaining about the increase in noise, and airlines are exceeding the criteria for noise. In this study, A330-300 airplane set flight conditions that are predicted to generate the most noise when taking off 32 runway at Gimpo International Airport, and predicted the noise as the NPD curve of the INM and AEDT programs. As a result of the analysis, it was considered that the noise at a specific point would generate higher noise than the noise criteria. Therefore, to avoid exceeding aircraft noise criteria at a particular point, supplementing the departure procedures by reflecting aircraft performance under flight conditions would reduce complaints from both airlines and local residents.

• Advances in aircraft and spacecraft science
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• 제10권1호
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• pp.1-18
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• 2023

This paper investigates the integrated control of an air-breathing hypersonic vehicle considering the safety of propulsion system under acceleration. First, the vehicle/engine coupling model that contains a control-oriented vehicle model and a quasi-one-dimensional dual-mode scramjet model is established. Next, the coupling process of the integrated control system is introduced in detail. Based on the coupling model, the integrated control framework is studied and an integrated control system including acceleration command generator, vehicle attitude control loop and engine multivariable control loop is discussed. Then, the effectiveness and superiority of the integrated control system are verified through the comparison of normal case and limiting case of an air-breathing hypersonic scramjet coupling model. Finally, the main results show that under normal acceleration case and limiting acceleration case, the integrated control system can track the altitude and speed of the vehicle extremely well and adjust the angle deflection of elevator to offset the thrust moment to maintain the attitude stability of the vehicle, while assigning the two-stage fuel equivalent ratio to meet the thrust performance and safety margin of the engine. Meanwhile, the high-acceleration requirement of the air-breathing hypersonic vehicle makes the propulsion system operating closer to the extreme dangerous conditions. The above contents demonstrate that considering the propulsion system safety will make integrated control system more real and meaningful.