• Current Industrial and Technological Trends in Aerospace
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• v.7 no.2
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• pp.40-47
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• 2009

In this paper, current industrial trend of simulator development which is widely spreaded and performed in globally is introduced. Usage of satellite simulator is becoming an essential choice since the complexity of satellite and mission is being continuously increased. Satellite simulation brings reduction of satellite development cost and of period which is consumed by test on satellite development for various phases. Further more, it can be used to reduce the development period of satellite since developed resource and knowledge is possible to be delivered to next program effectively.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.37-43
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• 2011

Lunar exploration program has been prepared with the aim of launch in the 2020's. As part of it, a lunar lander demonstrator has been developed which is the model for verifying all the system, such as structure, propulsion and control system before launch to deep space. After verifying all the system, the demonstrator will be evaluated by flight test. This paper deals with path tracking controller based on thrusters for the demonstrator. For this, first we derive equations of motion according to the allocation of thrusters and design the path tracking controller. The signal generated from the controller is continuous so PWPF(Pulse-Width Pulse-Frequency) modulator is adopted for generating on/off signal. Finally MATLAB simulation is performed for evaluating the path tracking ability and the final landing velocity.

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.377-382
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• 2010

In lunar explorer development program, computer simulator is necessary to provide virtual environments that vehicle confronts in lunar transfer, orbit, and landing missions, and to analyze dynamic behavior of the spacecraft under these environments. Objective of simulation differs depending on its application in spacecraft development cycle. Scope of use cases considered in this paper includes simulation of software based, processor and/or hardware in the loop, and support of ground-based flight test of developed vehicle. These use cases represent early phase in development cycle but reusability of modeling results in the next design phase is considered in defining requirements. A simulator architecture in which simulator platform is located in the middle and modules for modeling, analyzing, and three dimensional visualizing are connected to that platform is suggested. Baseline concepts and requirements for simulator development are described. Result of trade study for selecting simulation platform and approaches of defining other simulator components are summarized. Finally, characters of lunar elevation map data which is necessary for lunar terrain generation is described.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.45 no.5
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• pp.393-400
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• 2017

A virtual simulation test program to carry out the handling qualities of unmanned Rotorcraft has developed by using the MATLAB GUIDE(Graphic User Interface Development Environment). The handling quality evaluation program based on ADS-33E contributes to design the flight control system and to evaluate handling qualities. In addition, Linear Quadratic Tracker with Integrator(LQTI) attitude controller based on Linear Quadratic Regulator(LQR) for to rotorcraft BO-105C and the effects of the handling qualities is analyzed change to weight matrices of the Q and R.

• Journal of the Ergonomics Society of Korea
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• v.28 no.1
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• pp.37-51
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• 2009

The nuclear power industry in the world has recognized the importance of integrating non-technical and team skills training with the technical training given to its control room operators to reduce human errors since the Three Mile Island and Chernobyl accidents. The Nuclear power plant (NPP) industry in Korea has been also making efforts to reduce the human errors which largely have contributed to 120 nuclear reactor trips from the year 2001 to 2006. The Crew Resource Management (CRM) training was one of the efforts to reduce the human errors in the nuclear power industry. The CRM was developed as a response to new insights into the causes of aircraft accidents which followed from the introduction of flight recorders and cockpit voice recorders into modern jet aircraft. The CRM first became widely used in the commercial airline industry, but military aviation, shipboard crews, medical and surgical teams, offshore oil crews, and other high-consequence, high-risk, time-critical industry teams soon followed. This study aims to develop a CRM training program that helps to improve plant performance by reducing the number of reactor trips caused by the operators' errors in Korean NPP. The program is; firstly, based on the work we conducted to develop a human factors training from the applications to the Nuclear Power Plant; secondly, based on a number of guidelines from the current practicable literature; thirdly, focused on team skills, such as leadership, situational awareness, teamwork, and communication, which have been widely known to be critical for improving the operational performance and reducing human errors in Korean NPPs; lastly, similar to the event-based training approach that many researchers have applied in other domains: aircraft, medical operations, railroads, and offshore oilrigs. We conducted an experiment to test effectiveness of the CRM training program in a condition of simulated control room also. We found that the program made the operators' attitudes and behaviors be improved positively from the experimental results. The more implications of the finding were discussed further in detail.

• Journal of the Korea Society of Computer and Information
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• v.27 no.2
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• pp.203-212
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• 2022

In this paper, we propose to identify the factors and satisfaction of the selection of University and departments of One university freshmen. Research subjects were 499 freshmen in 2021 at K University located in G city. The data were analyzed by descriptive statistics, t-test, ANOVA, Scheffe' test and pearson's correlation coefficient using SPSS WIN 18.0. The results of this study showed that the internet/SNS was the highest in university information media, the school teacher was the highest in information provider, and the employment rate had the most impact on university registration decision. The University satisfaction score was 3.43, and there was a significant difference in gender(t=5.527, p=.019) and admission type(F=5.527, p<.001). The department satisfaction was 3.86 and there was a significant difference in the admissions type(F=3.004, p=.018). Univdrsity satisfaction and Department satisfaction showed a significant positive correlation(r=5.527, p<.001). Universities should improve their competitiveness through systematic admission information system.

• Physical Therapy Rehabilitation Science
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• v.7 no.3
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• pp.134-138
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• 2018

Objective: The aim of this research was to investigate the effects of functional electrical stimulation (FES) applied to the gluteus medius (Gm) and tibialis anterior (TA) during stair climbing in persons with stroke compared to FES applied to the TA only during stair climbing, and during stair climbing without FES in persons with stroke. Design: Cross-sectional study. Methods: Twenty subjects with stroke participated in this study. Subjects were included if: 1) they were diagnosed as stroke at least 6 months before; 2) had Mini Mental State Examination- Korean score of 24 or higher; 3) were able to climb a flight of 10 stairs independently (with or without walking aid). The patients walked 10 stairs 3 times with FES applied to the Gm and TA, only TA, or no FES. There was a 1-minute rest period between each bout. The assessments were made using the Timed Up & Down Test and the Wii Balance Board. Results: Stair climbing with FES applied to the Gm and TA was significantly faster than stair climbing with FES applied to the TA only and without FES (p<0.05). Stair climbing with FES applied to the Gm and TA exhibited significantly greater sway velocity than stair climbing without FES (p<0.05). However, maximal sway distances were not significantly different between groups. Conclusions: Stair climbing with FES applied to the Gm and TA can be an important component of a rehabilitation program for improving stair climbing ability in persons with stroke.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.3
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• pp.296-306
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• 2012

A series of numerical simulations are carried out to analyze a supersonic inlet buzz, which is an unsteady pressure oscillation phenomenon around a supersonic inlet. A simple but efficient geometry, experimentally adopted by Nagashima, is chosen for the analysis of unsteady flow physics. Among the two sets of simulations considered in this study, the effects of various throttling conditions are firstly examined. It is seen that the major physical characteristic of the inlet buzz can be obtained by inviscid computations only and the computed flow patterns inside and around the inlet are qualitatively consistent with the experimental observations. The dominant frequency of the inlet buzz increases as throttle area decreases, and the computed frequency is approximately 60Hz or 15% lower than the experimental data, but interestingly, this gap is constant for all the test cases and shock structures are similar. Secondly, inviscid calculations are performed to examine the effect regarding angle of attack. It is found that patterns of pressure oscillation histories and distortion due to asymmetric (or three-dimensional) shock structures are substantially affected by angle of attack. The dominant frequency of the inlet buzz, however, does not change noticeably even in regards to a wide range of angle of attacks.

• Journal of Advanced Navigation Technology
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• v.20 no.4
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• pp.305-313
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• 2016

International Civil Aviation Organization (ICAO) has recommended the adoption of performance-based navigation (PBN), which utilizes global navigation satellite system (GNSS). As a part of efforts to adopt PBN in South Korea, preparations have been made to implement GNSS. In Oct. 2014, Korea augmentation satellite system (KASS) was officially launched for development. A set of navigation devices need to be on-board for an airplane to utilize GNSS. GNSS navigation devices are used for different phases of flights through en-route, terminal, departure, approach and a wide variety of specification standards have been proposed for GNSS navigation. In this paper, we investigate the many proposed standards for GNSS navigation devices and their interfaces. This paper can be useful for designing procedures and flight test used in KASS implementation.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.41 no.9
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• pp.897-904
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• 2017

Optical equipment consists of various components, and a detector is mounted and operated on aircraft, tanks, and warships for target detection and classification. The structural stability and optical performance of aeronautical optical equipment operated at several kilometers of altitude are degraded owing to vibration generated in the aircraft. It is necessary to verify the structural stability and optical performance requirements of the equipment in vibration environment conditions during the design phase. In this study, vibration environment conditions were analyzed using a test standard and the measurements of the vibration generated in aircraft. The conditions were classified as endurance and operating vibration conditions for structural stability and optical performance verification, respectively. The structural stability was verified according to natural frequency analysis, response analysis for the endurance vibration condition, and static analysis. The optical performance was verified by applying the vibration response analysis results to the optical design/analysis program.