• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.3
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• pp.81-86
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• 2006

This paper deals with a driving current fault monitor design methodology for a DDV actuation system which has a dual hydraulic power supply system, and triplex electric control capability. A fault existing among these redundant channels should be detected accurately and removed timely, and the remaining channels are to be reconfigured in order to compensate the role of a removed faulty channel. An integrated analysis on the aerodynamics, flight control laws, and DDV actuation system is essential for the design of an actuation system fault monitor. A method to define a fault transient boundary which specifies a maximum travel of an actuation system caused by the first faulty operation is proposed based on the top level requirement on the fault effect specified in MIL-F-8785C.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.10
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• pp.46-52
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• 2004

A design methodology of the redundancy management for a duplex FBW flight control system is introduced. A statistical analysis is applied to determine two design parameters in CCM(Cross Channel Monitor), threshold and persistence count. An analytic redundancy, which is implemented using a Kalman filtering algorithm is considered. The application of an analytic redundancy to the FCS design of the smart UAV has several advantages of increasing the aircraft's survivability and breaking the tie-condition for a duplex FCS. All the redundancy management algorithms are verified through the numeric simulation for the flight dynamics of the XV-15 tilt rotor.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.384-387
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• 2019

2018년 Meltdown 공격이 발표된 이후 Foreshadow, ZombieLoad 등 다양한 종류의 마이크로아키텍처 기반 부 채널 공격과 방어 기법들이 발표되었다. 그중 Meltdown 공격을 원천 차단할 수 있는 KPTI (Kernel Page Table Isolation)는 커널 영역을 사용자 메모리 영역과 분리하여 커널 정보의 유출을 방어할 수 있으나, 최대 46%의 시스템 성능 저하를 가져온다. 본 연구는 런타임에 시스템콜 발생빈도를 분석하여 낮은 오버헤드로 Meltdown-type 공격을 탐지하고, 방어하는 프로그램을 개발하고 실험하였다. 개발한 Fault Monitoring Tool은 기존 시스템 대비 적은 오버헤드(최대 7%)로 악의적인 사용자를 구분해 내고 방어할 수 있었다.

• Journal of Service Research and Studies
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• v.12 no.1
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• pp.36-48
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• 2022

As the use of smartphones has rapidly increased due to the development of digital technology, the expansion of smartphones, and the COVID-19 incident, dependence on smartphones and the Internet is emerging as a serious social problem. As one of the solutions to the smartphone overdependence problem, the government and companies are releasing smartphone overdependence prevention applications. However, research on the effectiveness of smartphone overdependence prevention applications is insufficient. Therefore, this study selects 25 applications serviced in Korea as analysis targets and evaluates smartphone overdependence prevention applications in terms of function and service using the FGI survey method to identify problems and propose improvements. In the function evaluation, the functions of blocking illegal/harmful apps/websites, limiting smartphone usage time, and monitoring smartphone usage status are provided in most applications, so satisfaction scores are also highly evaluated. However, functions such as location check, smombie prevention, and body camphishing prevention served by some applications are evaluated low due to poor performance and poor accuracy. Classified by service provider, government-providing applications need to accurately perform functions and improve convenience of use. Mobile-Carrier-providing applications need to improve connectivity with other carriers and compatibility with other smart devices like smartphone, tablet, etc. Other private enterprise-providing applications need to open AS channels such as customer service centre and chatbot to improve service.