• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2003.11a
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• pp.208-212
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• 2003

An airborne radar is an essential aviation electronic system of the helicopter to perform various missions in all-weather environments. This paper presents the conceptual design results of the multi-mode pulsed Doppler radar system testbed model for helicopter. Due to the inherent flight nature of the hovering vehicle which is flying in low-altitude and low speed, as well as rapid maneuvering, the moving clutters from the platform should be suppressed by using a special MTD (Moving Target Detector) processing. For the multi-mode radar system model design, the flight parameters of the moving helicopter platform were assumed: altitude of 3 Km, average cruising velocity of 150knots. The multi-mode operation capability was applied such as short-range, medium-range, and long-range depending on the mission of the vehicle. The nominal detection ranges is 30 Km for the testbed experimental model, but can be expanded up to 75 Km for the long range weather mode. The detection probability of each mode is also compared in terms of the signal-to noise ratio of each mode, and the designed radar system specifications ate provided as a design results.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.195-203
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• 2017

Around 70% of domestic aircraft accidents in helicopter aircraft. The causal factors of the helicopter accidents are identified as human factors. People have focused mostly on unsafe acts to prevent the accident. The accidents should be analysed on human factors to reduce accident. The unsafe acts can be managed effectively if the latent failures were identified through the HFACS. This paper is to introduce about the latent failure classified by the HFACS and provide the analysis regarding the latent failure of the helicopters by the aviation safety advisors through the interviews.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.25 no.4
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• pp.161-169
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• 2017

The Human Factors Analysis and Classification System (HFACS) is a general human error framework originally developed and tested within the U.S. military as a tool for investigating and analyzing the human causes of aviation accidents. Based upon Reason's (1990) model of latent and active failures, HFACS addresses human error at all levels of the system, including the condition of aircrew and organizational factors. As a result, this study aims to examine the influence between the latent conditions based on HFACS. This study seeks to verify the factors of "Organizational Influence" effecting the "Precondition for Unsafe Acts" of HFACS. The results of empirical analysis demonstrated that the organizational influence had a positive influence on precondition for unsafe act, especially the "Organizational Climate" of organizational influence had even greater influence on precondition for unsafe acts.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.2
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• pp.41-45
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• 2010

It is often misled that Multi Pilot License is introduced by International Civil Aviation Organization for the shortage of pilots. The truth is, however, that the license is focused on efficient training of co-pilots in the airline transportation system which an autopilot system is increasing in the Multi Crew environment. ICAO has been researching on the license since 1982, and made it international standard on 2006. Currently, co-pilots trained under Multi-Crew Pilot License courses are continuously increasing over the world. Although the license has introduced to Korea in September 10, 2009, it has not won popular support yet. This paper will lead people to precise understanding of Multi-Crew Pilot License and suggest its introduction plan.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.18 no.4
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• pp.38-43
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• 2010

A continuing challenge in the aviation industry is how to safely keep aircraft in service longer with limited maintenance budgets. Therefore, all the advanced countries in aircraft technologies put great efforts in prediction of failure rate in parts and system, but in the domestic aircraft industry is lack of theoretical and experimental research. Prediction of failure rate provides a rational basis for design decisions such as the choice of part quality levels and derating factors to be applied. For these reasons, analytic prediction of failure rate is essential process in developing aircraft structure. In this paper, a procedure for prediction of failure rate for aircraft structural parts is presented. Cargo door kinematic parts are taken to illustrate the process, in which the failure rate for Hook part is computed by using Monte Carlo Simulation along with Response Surface Model, and system failure rate is obtained afterwards.

• Journal of Advanced Navigation Technology
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• v.8 no.1
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• pp.38-47
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• 2004

To achieve functions of doppler measurement, MTI(Moving Target Indicator), high-resolution, and others in radar system, all circuits of transmitter and receiver are to be performed in coherent system. In this paper, we use TWTA(Traveling Wave Tube Amplifier), STALO(Stable Local Oscillator) and COHO(Coherent Oscillator) to design of coherent radar transceiver, and calculates noise figure of designed receiver. Using radar equation calculated noise figure, maximum detecting range of each transmitting mode can be calculated.

• Journal of Aerospace System Engineering
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• v.9 no.2
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• pp.63-71
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• 2015

An aircraft engine is considered as the most important element among aircraft systems. Thus type certificate is required for an aircraft engine to ensure its safety under appropriate airworthiness standard. U.S. FAR Part 33 or European CS-E is widely adopted as an airworthiness standard for aircraft engines, and other representative countries of the world established own airworthiness standards under their regulations. In this paper, we compared differences of the requirements between FAR Part 33 and CS-E, and proposed the rulemaking items to harmonize Korean Airworthiness Standard for Aircraft Engines with worldwide standards and to contribute to growth of aviation industry.

• ETRI Journal
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• v.24 no.5
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• pp.405-408
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• 2002

In this paper, we discuss recovery schemes for errors occurring when image data encoded with variable length coding (VLC) is transmitted through additive white Gaussian noise (AWGN) and multiple-access interference in direct sequence code division multiple access (DS/CDMA) systems. VLC such as JPEG is so sensitive to channel errors that severe degradation in decoded images occurs even if only one or two bits have errors. This is due to the loss of synchronization at the image decoder. We propose a resynchronization scheme using a power allocation method in wireless DS/CDMA transmission. Through simulation, we know that the proposed method has a more robust resynchronization capability and higher objective and subjective quality than the conventional method.

• Proceedings of the KIEE Conference
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• 2002.11c
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• pp.134-137
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• 2002

This paper presents a robot manipulator kinematic motion control scheme based on velocity feedback loop. The desired joint velocity is obtained by the feature-based visual servoing and is used in the joint velocity control loop system for trajectory control of the robot manipulator. The asymptotic stability of the closed loop system is shown by the Lyapunov method. Effectiveness of the proposed method is shown by simulation and experimental results on a robot manipulator with two degree of freedom.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.16 no.2
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• pp.43-50
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• 2008

ICAO(International Civil Aviation Organization) Doc 9803의 국제규정에 의거하여 SMS(Safety Management System-안전관리시스템)의 대표적인 비행안전 모니터링 프로그램으로 인정된 신개념의 운항감사제도인 LOSA(Line Operations Safety Audit-항공운항 안전감사)를 항공사에서 실시하여 정상 운항시의 운항승무원을 관찰하여 실제의 안전취약 및 위협요소, Error를 포착하여 텍사스대학 인적요인 연구소에서 작성한 최종보고서의 분석을 통해 제도와 방안을 개선한다. 본 논문에서는 LOSA실행을 통한 승무원들의 위협 및 error의 유형과 발생율, 관리율 및 관리여부를 분석하여 설명하고 항공사내 개선인 SCP(Safety Change Process)를 소개하는데 있다.