• Korean Journal of Remote Sensing
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• v.35 no.3
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• pp.471-482
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• 2019

The mission of the high-resolution camera for the lunar exploration is to provide 3D topographic information. It enables us to find the appropriate landing site or to control accurate landing by the short distance stereo image in real-time. In this paper, the ground verification and analysis system using the multi-application stereo camera to develop the high-resolution camera for the lunar exploration are proposed. The mission test items and test plans for the mission requirement are provided and the test results are analyzed by the ground verification and analysis system. For the realistic simulation for the lunar orbiter, the target area that has similar characteristics with the real lunar surface is chosen and the aircraft flight is planned to take image of the area. The DEM is extracted from the stereo image and compose three dimensional results. The high-resolution camera mission requirements for the lunar exploration are verified and the ground data analysis system is developed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.4
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• pp.245-255
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• 2019

This paper describes on aerodynamic analysis based on the truncation rate of guided-weapon nose using computational fluid dynamics. The shape to perform the analysis is only the body of the guided weapon and the diameter to length ratio is 10.7. Three nose shapes were selected and hemisphere, 25% and 50% truncation were compared. For the accurate CFD analysis of the body, the grid method and the analytical method were selected and verified using NASA wind tunnel test data. For the three nose shapes, the drag analysis for the flight Mach number is 6~20% different. This difference was analyzed by the pressure distribution from nose to base.

• Journal of the Korea Fashion and Costume Design Association
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• v.23 no.3
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• pp.11-21
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• 2021

Virtual reality is currently mainly used in games, but is starting to be applied as a variety of media fields, such as broadcasting and film. Virtual reality provides more fun than reality, and can provide new experiences in areas that cannot be experienced in reality due to the constraints of time, space, and environment. In particular, as the social non-contact arena has increased due to COVID-19, it is being applied to education, health, and medical industries. The contents are further expanding into design and military fields. Therefore, the purpose of this study was to observe the change in distribution of load and pressure felt by the body in the flying state while wearing a short pants harness, which are mainly used in the game and entertainment industry. In the experiment, the average pressure in the flying state was measured by attaching a pressure sensor to the back and front of a human mannequin. As a result, it was confirmed that the load concentrated on the waist in the flying state was 44 N, with a pressure of 1353 kPa. The pressure distribution was concentrated in front of the center of gravity, and was measured was at 98% by the pressure sensors, with an average pressure value of approximately 15 kPa, and a pressure value of approximately 12 kPa at the back, which was measured at 67% by the pressure sensor. The results of the load and pressure distribution measurement are presented as fundamental data to improve the wearability and comfort of harnesses in the future, and are compared to actual measured pressure values by analyzing the clothing pressure in flight through virtual wear of harnesses through the CLO 3D program.

• Journal of Advanced Navigation Technology
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• v.22 no.2
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• pp.70-75
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• 2018

The mounted store on an aircraft shall be subjected to an ground separation test to verify that a safe separation has been made before it is actually installed to the aircraft. In this study, ground ejection test was conducted with dummy missile to verify the stability of the drop on the land. Bomb rack unit essential to testing ground ejection test, operate at high pressure and produce a significant ejection force to push the missile away from any large orifice. Bomb rack unit modified their bombe pressure and orifice diameter to photograph the drop movement of dummy missile with high-speed camera and to analyze their drop displacement and speed. It is considered useful to provide the initial data for the ejection force analysis on aircraft with actual flight and to carry out the ground separation tests of aircraft with future developments.

• Journal of Advanced Navigation Technology
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• v.25 no.3
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• pp.256-266
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• 2021

Domestic and foreign studies point to human factors as the main cause of unmanned aerial vehicle accidents, and HFACS is introduced as a technique to effectively analyze these human factors. Until now, domestic and foreign cases of analyzing the human factors of unmanned aerial vehicle accidents using HFACS were mainly targeted by military unmanned aerial vehicles, which can be used as an objective cause identification and similar accident prevention tool. In particular, identifying the focus of HFACS application considering the performance and operation conditions of domestic civilian unmanned aerial vehicles is expected to greatly help identify the cause and prevent recurrence in the event of an accident. Based on HFACS version 7.0, this study analyzed the accident investigation report data conducted by Korea Aviation and Railway Accident Investigation Board to identify the focus of HFACS application that can be used for domestic civilian unmanned aircraft accident investigations.

• The Journal of Korean Institute of Information Technology
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• v.17 no.10
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• pp.57-63
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• 2019

Motion errors which are caused by several reasons, non-ideal path, errors of navigation systems, and radar system errors, have to be corrected. Motion compensation methods can compensate the motion error, but not exactly. To correct these residual errors, several autofocus methods are invented. A popular method is phase gradient autofocus (PGA). PGA does not assume specific circumstances, such as isolated point targets and shapes of errors. PGA is an iterative and adaptive method, so that the processing time is the main problem for the real time processing. In this paper, the improved method to select targets for PGA is proposed to reduce processing time. The variances of image pixels are used to select targets with high SNR. The processing of PGA with these targets diminishes the processing time and iterations effectively. The processed results with real radar data, obtained by flight tests, show that the proposed method compensates errors well, and reduce working time.

• Journal of Convergence for Information Technology
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• v.10 no.12
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• pp.39-48
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• 2020

This study is a qualitative study to understand the meaning and essential structure of the experiences of Tae-um (Workplace bullying) experienced in hospital organizations for nurses. The participants were interviewed by selecting 10 persons who agreed to participate in the research through SNS in the workplace with the cooperation of the hospital. The collected data were analyzed using Colaizzi's phenomenological method. As a result of the study, Tae-um in the hospital organization of clinical nurses was divided into 4 categories(Taking the terrible first step, A series of hardships that never end, Hang on to myself, Wings flight of for adaptation) and 16 It was derived from themes. In conclusion, it was confirmed that Tae-um, not only new nurses, but even nurses who have accumulated careers, are still in progress, so they are adapting to the difficult hospital organization. Therefore, if a psychological support program for nurses is introduced, it will contribute to solving the Tae-um problem and establishing an organizational culture where nurses are respected.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.9
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• pp.771-780
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• 2021

The space Debris laser ranging system is called to be a definite type of satellite laser ranging system that measures the distance to satellites. It is a system that performs POD (Precise Orbit Determination) by measuring time of flight by firing a laser. Distance precision can be measured in mm-level units, and it is the most precise system among existing systems. Currently, KASI has built SLR in Sejong and Geochang, and utilized SLR data to verify the precise orbits of the STSAT-2C and KOMASAT-5. In recent years, due to the fall or collision of space debris, its satellites have been threatened, and in terms of security, laser tracking of space objects is receiving great interest in order to protect their own space assets and protect the safety of the people. In this paper, a 1.5m-class main mirror was applied for the system design of a multipurpose laser tracking system that considers satellite laser ranging and space object laser tracking. System preliminary performance analysis was performed based on Link Budget analysis considering specifications of major components.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.26 no.6
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• pp.890-896
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• 2022

In this paper, gimbal camera control through smart gloves was implemented to increase convenience and accessibility to the control of drones used in various fields. Smart gloves identify human gestures and transmit signals through Bluetooth. The received signal is converted into a signal suitable for the drone through a GCS (Gound Control Station). Signals from smart gloves are expressed in a quaternion method to prevent gimbal locks, but for gimbal cameras, conversion is required to use Roll, Pitch, and Yaw methods. The data conversion mission is performed in the GCS. The GCS transmits an input signal to the control board of the drone through Wi-Fi. The control board generates and outputs the transmitted signal in a PWM manner. The output signal is input to the gimbal camera through the SBUS method and controlled. The input signal of the smart glove averaged 0.093 s and up to 0.099 s to output to the gimbal camera, showing that there was no problem in real-time use.

• Journal of the Korea Institute of Military Science and Technology
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• v.25 no.4
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• pp.364-371
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• 2022

Surface state change of ammunition generated during the storage period increases the surface roughness and this affects the flight of ammunition, but there are no research results quantitatively indicating this. In this study, the drag force for each Mach number of howitzer shells was calculated through CFD to which the surface data of the howitzer shell was applied, and analysis of trajectory was performed using drag force values as an input of the 4th Runge-Kutta method, and the degree of decrease of the maximum range caused by the surface roughness of the howitzer shell was estimated. As a result, it was confirmed that the maximum range of howitzer shell with high surface roughness was 1.12 % shorter than that of howitzer shell without roughness. It was confirmed that the effect of surface roughness on the trajectory is not negligible.