• Journal of Advanced Navigation Technology
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• v.27 no.6
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• pp.710-715
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• 2023

Urbanization brings many challenges such as traffic, housing, and environment. To solve these problems, researchers are working on new transportation systems like urban air mobility (UAM). UAM aircraft should fly safely without burdening the existing air traffic system in the early stage of low-density operation. The airspace should also be managed and operated efficiently. Therefore it is important to make urban air traffic predictable by using corridors and collecting data on low-density operations in the early stage. For this purpose various simulations are needed before operation to create scenarios that estimate potential collisions between UAM aircraft and to evaluate the risks of aircraft spacing, loss of separation (LoS), and near mid air collision (NMAC). This paper focuses on identifying the requirements and considerations for setting separation standards for urban air traffic based on the results of studies.

• Journal of Convergence Society for SMB
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• v.6 no.1
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• pp.7-15
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• 2016

As most devices in a wide range of automotive, aerospace, and missile have built-in software that controls the system behaviors, the safety of the software is growing in its importance. That is, the software safety has emerged as one of big issues because the threat of accidents caused by software malfunction is rising. Accident by software can be occurred from user mal-operation, but the fundamental reason of the accident comes from insufficient verification of the safety in software development process. Therefore, this paper presents how the software safety analysis and management activities should be done in the development process. In particular, we propose how to apply the safety analysis and management activities in the prototype or incremental development process.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.2
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• pp.169-179
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• 2010

Satisfying the same probability of loss of control and essentially two fail operative performance with a triplex computer architecture requires a lot of modification of the conventional redundancy management design techniques, previously employed in quadruplex digital flight control computer. T-50 FCS for triplex redundancy management design applied an advanced digital flight control architecture with an I/O controller which is functionally independent of the digital computer to achieve the same reliability and special failure analysis and isolation schemes for fail operational goals with a triplex configuration. The analysis results indicated that the triplex flight control system is to satisfy the safety requirement utilizing the advanced flight control techniques and the system performance of the implemented flight control system was verified by failure mode effect test.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.785-788
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• 2009

The flight data processing system is the system which processes and manages all flight related data for the aircraft control and performs the trajectory modeling. It takes charge of the role of performing the core function of the integrated information processing system for the flight control. For the safe aircraft's flight, the information transfer and exchange among air traffic control units are the essential element through the flight data processing. Therefore, for the development of the flight data processing system we are going to analyze its function and look into the necessary consideration in a design in this paper.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.1479-1481
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• 2012

본 논문은 내부 혹은 외부의 바이러스의 피해 및 비행자료 변조 및 수정 등의 해킹 발생에서 비행자료 시스템의 가용성, 신뢰성 및 무결성을 강화시켜 비행자료시스템 운영 시 관제 서비스를 마비시키는 다양한 사이버 테레에 대응하여 실시간으로 자동으로 재해를 복구하는 시스템 및 그 방법에 대한 것이다. 비행자료시스템 실시간 자동재해복구시스템은 임베디드 시스템을 제공하며, EWF(Enhanced Write Filter)를 이용하며 OS(Operating System)을 보호하여 시스템을 안전하게 운용할 수 있는 장점을 갖는다.

• Journal of the Korea Safety Management & Science
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• v.13 no.2
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• pp.1-8
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• 2011

The Chicago Convention in 1944 made important contributions to aviation safety improvement, building an aviation safety monitoring system for its signatory countries. As ICAO is now on the verge of changing its supervision system from self-reporting to preventive Continuous Monitoring Approach(CMA) in 2013, we also expect our own safety system to make a progress accordingly. The government is pushing ahead with plans to build an integrated safety management system at government level that satisfies international standards and reflects domestic features. To this end, this report proposes the most effective system-building model, by analyzing the current status of the system that is in use and meets the requirements of international aviation agencies.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.3
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• pp.58-63
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• 2008

ICAO has recommended ADS-B implementation that is considered as next generation surveillance system to meet the air traffic capability and aviation safety. However, safety verification for the new ADS-B technology should be carried out in advance. FAA performed a preliminary hazard analysis for ADS-B equipped aircraft through Capstone program in Alaska in order to reduce aviation accidents. The present study deals with ADS-B concept, FAA Capstone program and PHA for ADS-B equipped aircraft. We expect that this paper will be a valuable material to assess ADS-B risk when it is applied to the domestic environment.

• Journal of Aerospace System Engineering
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• v.16 no.4
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• pp.77-87
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• 2022

The Precision Aerial Delivery System is an instrument designed to improve the poor landing accuracy of aerial delivery system with conventional circular parachutes, and is equipped with an Airborne Guidance Unit to safely transport supplies to the desired destination. Currently, the landing accuracy of the PADS product is reported as CEP₅₀ 100m and also differs significantly, depending on the actual topography and weather environment. In this study, HILS was constructed based on the 6DOF nonlinear modeling of PADS to analyze the maneuver characteristics of Ram Air Parachute under wind environments. By using the new algorithm a precision soft landing algorithm including Energy Management and Final Approach is designed. HILS results show that it is possible to achieve a precise soft landing within CEP₅₀ 40m, and it can be exploited to develop an actual PADS drop test.

• Journal of Aerospace System Engineering
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• v.17 no.1
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• pp.51-58
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• 2023

Hypergolic propellants, which can ignite themselves without an ignition source, are difficult to handle due to their corrosiveness and toxicity. Therefore, it is necessary to develop green hypergolic propellants with little or no toxicity. In this study, basic research on green hypergolic ignition propellants was conducted. With 95% hydrogen peroxide as an oxidizer and CNU_HGFv1 as a fuel, ignition and combustion characteristics of propellants were evaluated through a drop test, an ignition test, and a combustion test. As a result of the drop test, the ignition delay time was 9.7 ms. It was 27 ms in the ignition test, which was fast enough to be used as a propellant. As a result of the combustion test, a combustion efficiency of 95.4~98.1% was achieved at about 11.7 bar. It was confirmed that fast and stable combustion was possible without hard start or combustion instability.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.10
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• pp.821-829
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• 2020

Health management system of airborne software repairs runtime errors to provide safety and to reduce cost of maintenance. It is critical to on-the-fly repair order violation errors, because it is difficult to identify them at the development phase. Previous work, called Repairing Atomicity Violations (Repairing-AV) diagnoses order violations for each access event by comparing execution order of accesses. As a result, Repairing-AV has time overhead that is proportional to the number of access events to shared variable. This paper presents a tool called On-the-fly Repairing System (ORS) that can repair order violations of object methods containing access events. The ORS diagnoses order violations by using correct order of object methods, and treats them by stalling its thread where the error is about to occur. Experimentation with five synthetic programs shows that ORS is more efficient than Repairing-AV when the number of access events is greater than sixty.