• International Journal of Contents
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• 제14권2호
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• pp.1-6
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• 2018

In a wireless mobile communication system, a pilot signal has been considered to be a necessary signal for estimating a changing channel between a base station and a terminal. All mobile communication systems developed so far have a specification for transmitting pilot signals. However, although the pilot signal transmission is easy to estimate the channel,(Ed: unclear wording: it is easy to use the pilot signal transmission to estimate the channel?) it should be minimized because it uses radio resources for data transmission. In this paper, we propose a pilotless channel estimation scheme (PCE) by introducing the clustering method of unsupervised learning used in our deep learning into channel estimation.(Ed: highlight- unclear) The PCE estimates the channel using only the data symbols without using the pilot signal at all. Also, to apply PCE to a real system, we evaluated the performance of PCE based on the resource block (RB), which is a resource allocation unit used in LTE. According to the results of this study, the PCE always provides a better mean square error (MSE) performance than the least square estimator using pilots, although it does not use the pilot signal at all. The MSE performance of the PCE is affected by the number of data symbols used and the frequency selectivity of the channel. In this paper, we provide simulation results considering various effects(Ed: unclear, clarify).

• Journal of the Korean Society for Aviation and Aeronautics
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• 제20권2호
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• pp.18-25
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• 2012

The availability of the GPS signal has been expanded greatly in the field of society overall through the development and construction of the GNSS(Global Navigation Satellite System). Furthermore, in the military, aviation and field of space, the GPS signal is applied widely through the combination of INS consisting of gyroscope and accelerometer, IMU, AHRS with the addition of magnetic sensor. Particularly, the performance of these equipments or sensors is very important with GPS and PAR(Precision Approach Radar) in the flight control of the aircraft. This paper deals with MATLAB simulation and ROLSO(Reduced Order Luenberger State Observer) design to reduce the load of system and realize the stable lateral direction approach control in an appropriate time for reduction of the horizontal error which is importantly considered while an aircraft lands instead of the FOLSO(Full Order Luenberger State Observer) using all measurement values. Consequently, ROLSO is expected to be used for the aircraft's attitude control in the aircraft landing causing the burden to the pilots.

• Journal of the Korea Institute of Military Science and Technology
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• 제15권6호
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• pp.746-753
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• 2012

ROK military helicopters are frequently exposed to the hazard situations due to the characteristic of operation. Especially, helicopter accident may lead to critical damage of human and structure. Accordingly, pilots have to train the autorotation procedures and learn the skill to prevent hard landing. In this paper, the behavior of skid gear subject to the helicopter autorotation was conducted by using numerical method. The computer simulation approach by using finite element method was employed to accomplish this goal. Additionally, the behavior of skid gear was evaluated for the different landing conditions. In conclusion, the maximum stress concentration was occurred at the attached area of skid cross-tube to the fuselage. Also, it was revealed that the most proper attitude was level landing to prevent hard landing.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 한국항해항만학회 2012년도 추계학술대회
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• pp.160-161
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• 2012

The traditional theory regarding the pivot point of a ship during maneuvering, so called apparent pivot point, is located nearly at 1/3 ship's length from the bow when the ship is moving ahead, and between 1/4 ship's length from the stern and the rudder post when going astern. The pivot point is sometimes considered to be the centre of leverage for forces acting on the ship. However, the pivot point is located out of ship due to strong lateral force, such as current and it is very inconvenient to use during maneuvering a ship. In this paper firstly, pivot points due to ship's condition are investigated carefully. And then the center of lateral resistance used at the present are determined. While a new lateral force is added, we can compare the pivot point with the center of lateral forces. Finally, we will suggest the center of all lateral forces for maneuvering instead of pivot point. Especially, it will be very helpful for pilots to handle ships in simulation.

• Journal of the Korean Society for Precision Engineering
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• 제21권9호
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• pp.135-141
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• 2004

Anti-shock performance is one of the most important design specifications of TFT-LCD modules. Since they are adopted fur major display units of many mobile applications such as lap-top PCs, cellular phones, and palm pilots, they are able to accommodate and endure high level transient mechanical energy inputs. For the reasons, not only the LCD unit manufacturers but their customers like PC makers perform a series of strict impact/drop test on the units. Currently, designers are mostly relying on their own trial-error based experience for the anti-shock design. Thus those designs depending on only experience may result in disqualification from the drop/impact test during final product evaluation. Those shock failures of any new designs are prohibitive for both LCD and PC manufacturers. In order to avoid this problem, many designers are focusing on the development of computer-aided design tools that is directly connected to shock simulation capabilities and then shock-proof design cycle time could be significantly reduced. Development of an integrated CAE system for the shock-proof design is presented in this article. At every stages of the development of present work, practical industrial applicability and mass production feasibility are seriously considered and tested so that the system is to be used in the LCD design engineering field.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제27권1호
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• pp.26-33
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• 2019

It is necessary to establish a UAV pilot license and training system because the number of UAV-related accidents has rapidly risen. Most of accidents are caused by the human factors such as the lack of control skill and aviation knowledge. In this paper, we investigate licensing policy of small UAV pilots and examine the level of UAV licensing system and classification criteria based on comparative analysis of national cases such as USA, UK and China. Recently, the Ministry of Land, Infrastructure and Transport Affairs is planning to improve the safety regulation by taking into account the risk level of the licensing system, which has been classified according to the existing weight and commercial purpose. From the comparative analysis, we suggested a improvement policy for UAV licensing system in the view of pilot license segmentation, beyond Visual Line-of-sight flight and high risk UAV for non-commercial.

• 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.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제27권2호
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• pp.47-53
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• 2019

The development of the aviation industry and the changes in the military operation mission environment are demanding more long - distance operation (long - time flight), and such a flying environment is a risk factor for fatigue - related accidents. For the aviation related organizations such as ICAO and FAA, fatigue risk management system (FRMS) are applied along with flight time restriction regulations to prevent fatigue related accidents. The most important process in FRMS is fatigue risk management. Fatigue risk management systematically manages fatigue through scientific fatigue risk data collection and fatigue risk assessment. The purpose of this study is to applicate the assessment of scientific fatigue risk management to pilots of airplanes engaged in long flight. We reviewed the current state of risk management and FRMS through previous research. We also developed fatigue risk management indicators and examined the validity of internationally recognized fatigue risk data collection methods and fatigue risk assessment tools. There are 134 mission (flight) data used for development. In order to verify the indicators, the fatigue risk score between the items was assigned through pair-wise comparison. In addition, the verify test results were normalized.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제46권11호
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• pp.961-968
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• 2018

Airborne display systems provide pilots with a variety of information needed to operate aircraft. Software faults in the display system can seriously affect the operation of the aircraft, because it can provide inaccurate information to the pilot. Therefore, the software faults are identified and eliminated through ground testing and flight testing. This paper presents an analysis tool called FDR (flight data replay) for flight test of airborne display software. This tool works in real time with the mission computer of aircraft. Also, the tool reproduces the functional error conditions that appear in the display systems by applying flight test data to the display software.

• Journal of the Korean Society for Aviation and Aeronautics
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• 제28권4호
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• pp.141-146
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• 2020

The International Civil Aviation Organization (ICAO) developed Doc 9995 "Manual of Evidence-based Training," with the intention of providing guidance by establishing a new methodology for the development and conduct of a recurrent training and assessment program. The airline pilot training regulations were largely based on the evidence of hull losses from early generation jets, and in order to mitigate a risk, simply repeating an event in a training program was sufficient. At the time, studies concluded that it was time to change the paradigm of training and assessment program for pilots. One airline alone implemented Evidence-Based Training (EBT) program in their flight crew training and assessment program while another airline partially implemented the EBT program. In the regulatory framework of MOLIT, specific EBT regulations have not been established yet. Therefore, it is recommended to develop rules and standards that comply with ICAO SARPs as soon as possible. In this study we review the key steps in the implementation of the baseline EBT, approval process of baseline EBT program, and policy options regarding the implementation of EBT. It will provide guidance to operators, Approved Training Organizations (ATO), and stakeholders.