• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.8-10
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• 2012

위성을 전체적으로 제어하는 탑재소프트웨어가 동작하는 주 메모리와는 별도로 세이프가드 메모리가 있다. 세이프가드 메모리는 주로 위성의 장애관리를 위해 사용되는 것으로 프로세서 리셋 시에 전체적으로 초기화가 수행되는 주 메모리와는 달리 별도의 전원을 사용하여 항상 Power-ON 상태를 유지하고 주/부 2개의 메모리가 주/부 프로세서와 Cross-Strap으로 연결되어 어느 프로세서에서든 접속이 가능하도록 구성되어 있다. 위성에 심각한 장애가 발생하여 정상적인 운영이 불가능한 경우, 위성은 Fail-over 과정을 거치게 되는데, Fail-over 과정에서 2개의 세이프가드 메모리의 비상운영데이터 영역에 장애 발생원인 및 프로세서 리셋 이후에 필요한 정보들을 기록하고, 미리 정해진 Backup 하드웨어를 이용하여 시스템 초기화가 수행된다. Backup 하드웨어를 통하여 프로세서가 정상적으로 Boot-up되면 세이프가드 메모리에 저장된 비상운영데이터를 이용하여 위성의 장애발생 원인을 파악하고, 정상운영모드로 복귀하는 절차를 거치게 된다. 본 논문은 저궤도 위성에서 사용되는 세이프가드 메모리 운영방식에 대해 기술한 것이다.

• The Journal of Korea Robotics Society
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• v.18 no.3
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• pp.337-345
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• 2023

In this paper, we propose a 3D LiDAR sensor-based costmap generation and path planning algorithm using it for reliable autonomous flight in complex indoor environments. 3D path planning is essential for reliable operation of UAVs. However, existing grid search-based or random sampling-based path planning algorithms in 3D space require a large amount of computation, and UAVs with weight constraints require reliable path planning results in real time. To solve this problem, we propose a method that divides a 3D space into several 2D spaces and a path planning algorithm that considers the distance to obstacles within each space. Among the paths generated in each space, the final path (Best path) that the UAV will follow is determined through the proposed objective function, and for this purpose, we consider the rotation angle of the 2D space, the path length, and the previous best path information. The proposed methods have been verified through autonomous flight of UAVs in real environments, and shows reliable obstacle avoidance performance in various complex environments.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.2
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• pp.72-80
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• 2023

Line Operations Safety Audit (LOSA) is a well known preventive aviation safety program for Threat and Error management (TEM). High quality LOSA data suitable for safety management is obtained when a flight crew flies at the same level of attention as ordinary flight. Factors contributing to LOSA data quality may include flight crew's understanding on LOSA purpose, observer's career, and characteristics of the organization responsible for LOSA operations. This study explored purposes of TEM and LOSA, as well as their relationship. Previous studies mentioned quality of LOSA data can be influenced by heuristic judgment, hawthorne effect, and priming effect. This study recognized the importance of LOSA data quality to be effectively used for preventive safety management. It was confirmed that the level of understanding on LOSA concept, experience of the observer, and the characteristics of the department in charge of LOSA operation could affect the quality of LOSA data.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.31 no.3
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• pp.161-171
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• 2023

The traditional safety management method starts with the misconception that similar accidents will recur if the inappropriate behavior of the person who caused the accident is investigated and punishment is not judged. However, in modern safety management, incidents or situations occur when negative conditions latent in the system are mutually influenced and triggered. The precedent for revoking the disposition of suspension of first officer A of Eastar Jet, which won a legal lawsuit against the administrative regulatory authority, is a representative example that will serve as an opportunity for the administrative regulatory authority to break away from the punishment-oriented safety management method of the past. On the other hand, airmans and air carriers also need to have a clear understanding of flight regulations, and when judicial judgment is required, predictable and effective legal effects can be obtained by preparing clear standards for flight regulations. In addition, administrative regulatory authorities expect a change from the punishment-oriented safety management policy of the past to a systematic safety management policy.

• The Korean Journal of Air & Space Law and Policy
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• v.30 no.2
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• pp.403-425
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• 2015

The Chicago Convention and Annexes have become the basis of aviation safety regulations for every contracting state. Generally, the State's aviation safety regulations refer to the Standards and Recommended Practices(SARPs) provided in the Annexes of the Chicago Convention. In order to properly reflect international aviation safety regulations, constant studies of the aviation fields are of paramount importance. This Paper is intended to identify the main differences between korean and foreign regulation and suggest a few amendment proposals on Mixed-fleet Flying(at or more two aircraft type operation) of flight crew. Comparing with these regulations, the korean regulations and implementations have some insufficiency points. I suggest some amendment proposals of korean regulations concerning Mixed-fleet Flying that flight crew operate aircraft of different types. Basically an operator shall not assign a pilot-in-command or a co-pilot to operate at the flight controls of a type of airplane during take-off and landing unless that pilot has operated the flight controls during at least three take-offs and landings within the preceding 90 days on the same type of airplane or in a flight simulator. Also, flight crew members are familiarized with the significant differences in equipment and/or procedures between concurrently operated types. An operator shall ensure that piloting technique and the ability to execute emergency procedures is checked in such a way as to demonstrate the pilot's competence on each type or variant of a type of airplane. Proficiency check shall be performed periodically. When an operator schedules flight crew on different types of airplanes with similar characteristics in terms of operating procedures, systems and handling, the State shall decide the requirements for each type of airplane can be combined. In conclusion, it is necessary for flight crew members to remain concurrently qualified to operate multiple types. The operator shall have a program to include, as a minimum, required differences training between types and qualification to maintain currency on each type. If the Operator utilizes flight crew members to concurrently operate aircraft of different types, the operator shall have qualification processes approved or accepted by the State. If applicable, the qualification curriculum as defined in the operator's Advanced Qualification Program could be applied. Flight crew members are familiarized with the significant differences in equipment and/or procedures between concurrently operated types. The difference among different types of airpcrafts decrease and standards for these airpcrafts can be applied increasingly because function and performance have been improved by aircraft manufacture company in accordance to basic aircraft system in terms of developing new aircrafts for flight standard procedure and safety of flight. Also, it becomes more necessary for flight crews to control multi aircraft types due to various aviation business and activation of leisure business. Nevertheless, in terms of flight crew training and qualification program, there are no regulations in Korea to be applied to new aircraft types differently in accordance with different levels. In addition, it has no choice different programs based on different levels because there are not provisions to restrict or limit and specific standards to operate at or more than two aircraft types for flight safety. Therefore the aviation authority introduce Flight Standardization and/or Operational Evaluation Board in order to analysis differences among aircraft types. In addition to that, the aviation authority should also improve standard flight evaluation and qualification system among different aircraft types for flight crews to apply reasonable training and qualification efficiently. For all the issue mentioned above, I have studied the ICAO SARPs and some state's regulation concerning operating aircraft of different types(Mixed-fleet flying), and suggested some proposals on the different aircraft type operation as an example of comprehensive problem solving. I hope that this paper is 1) to help understanding about the international issue, 2) to help the improvement of korean aviation regulations, 3) to help compliance with international standards and to contribute to the promotion of aviation safety, in addition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2000.04a
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• pp.6-6
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• 2000

On-orbit thermal behavior of KOMPSAT (Korea Multi-purpose Satellite) propulsion system employing hydrazine (N$_2$H$_4$) liquid monopropellant is addressed. Thermal control performance to prevent propellant freezing in spacecraft-operational orbit was verified by flight telemetry data obtained during LEOP (Launch and Early Operation Phase). Results are depicted in terms of temperature history during several orbits selected and are compared with acceptable temperature ranges of system components. Cyclic behavior of temperature is reduced into duty cycles of the avionics heaters and subsequently converted into the electrical power required to keep away from propellant freezing. Temperature of each component which was achieved under on-ground thermal-balanced condition of spacecraft, is presented for comparison with the flight data, additionally.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.15 no.1
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• pp.26-37
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• 2007

This study examines how the cognitive-behavioral group counseling influence on the career stress, the self-efficacy and the optimism for the coping of the career stress of students in department of aeronautical science and flight operation of H Aerospace University. The subjects of this research were 27 freshmen in the department of aeronautical science and flight operations of H Aerospace University. They were divided into 2 groups: experimental group and control group. The experimental group got the group counseling program 7 times for 3 weeks. The results show that the cognitive-behavioral group counseling program can be a very useful tool to reduce career stress and to enhance self-efficacy and optimism of students.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.3
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• pp.61-67
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• 2017

The Nose Landing Gear(NLG) of Rotary Wing Aircraft is an essential equipment in Landing System for pilot to perform a flight mission. It supports the fuselage at ground and absorbs the impact from the ground when landing, thereby, these functions sustain operational capability for pilot and crew. However, the A aircraft caused stick-slip behavior when it was stationed on the ground. Therefore, this paper summarizes pilot comment in operation which are classified by cause of occurrence and the troubleshooting process about each comment. It also describes design improvements which was derived from troubleshooting and suggests verification results of flight test.

• Journal of Astronomy and Space Sciences
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• v.27 no.4
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• pp.407-412
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• 2010

Software reusability is one of key factors which impacts cost and schedule on a software development project. It is very crucial also in satellite simulator development since there are many commercial simulator models related to satellite and dynamics. If these models can be used in another simulator platform, great deal of confidence and cost/schedule reduction would be achieved. Simulation model portability (SMP) is maintained by European Space Agency and many models compatible with SMP/simulation model interface (SMI) are available. Korea Aerospace Research Institute (KARI) is developing hardware abstraction layer (HAL) supported satellite simulator to verify on-board software of satellite. From above reasons, KARI wants to port these SMI compatible models to the HAL supported satellite simulator. To port these SMI compatible models to the HAL supported satellite simulator, simulation scheduler is preliminary designed according to the SMI standard.

• 한국전산유체공학회:학술대회논문집
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• 2004.10a
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• pp.165-171
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• 2004

Smart UAV, which adopting tiltrotor aircraft concept, requires long endurance and high speed capability simultaneously These two contradictable flight performances are hard to meet with single wing concept and inevitably require the operation of flap system which should reveal optimal performance for each flight mode. In order to design SUAV flaperon satisfying the performance requirement, various configurations are generated and their aerodynamic performances are analyzed using numerical flow computations around flaps. Considering aerodynamic performance and manufacturing simplicity, a final flap configuration is selected.