• 한국항공운항학회지
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• 제22권1호
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• pp.130-135
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• 2014

FOD(Foreign Object Debris) has the potential threat to damage aircraft during critical phases of take-off and landing roll with some objects including metal on the runway. FOD can be found anywhere on an airport's air operation areas such as runway, taxiway and apron. It can lead to catastrophic loss of life and airframe, and increased maintenance and operating costs. In this paper, we defined FOD and surveyed its riskiness and necessity of automatic FOD detection system. We compared the requirements of the environment in Korea to the FAA advisory circular. Also we analyzed operation methods of FOD detection systems already installed at some airports. Based on the surveys mentioned above, we propose hybrid type of FOD detection system considering the environment in Korea which uses millimeter wave radar, optical camera and thermal imaging camera to detect FOD efficiently. In management approach, fixed type of the system should be installed for real-time monitoring, and mobile type of the system can be used additionally.

• 한국항행학회논문지
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• 제20권3호
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• pp.210-217
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• 2016

전 세계 공항의 이동지역 내 이물질인 FOD (foreign object defective)에 의한 피해 량이 연간 2억불에 달하고 있다. 2000년 샤를드골 공항에서는 FOD로 인한 133명의 인명피해가 발생하기도 했다. 국내에도 각 공항별로 FOD로 인한 사고발생 및 장비의 수리 등 직 간접적인 피해가 발생하고 있는 상황이다. 이에 항공안전기술개발 사업의 일환으로 공항 내 항공기 이동지역 이물질 자동탐지 시스템의 개발이 진행 중에 있다. 분석 결과에 의하면 운용 방식의 특성상 민간 공항의 경우 고정식 감시를 요구했고 군 공항은 이동식을 선호했다. 본 논문에서는 군 민간 FOD 탐지 시스템의 요구조건을 파악하여 국내 조건에 맞는 최소 성능 사양을 분석하였다.

• 한국소음진동공학회논문집
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• 제12권8호
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• pp.648-656
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• 2002

This paper presents the identification of temperature-dependent hysteresis of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model for the PMA-based ER fluid is identified using experimental multiple first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• Bulletin of the Korean Chemical Society
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• 제7권6호
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• pp.433-438
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• 1986

Two new types of NMR shift reagents, one giving dipolar-only and the other giving contact-only shifts, can be prepared simply by mixing two appropriate $Ln(fod)_3$(Ln = Pr, Nd, Eu, and Yb) reagents in certain ratios. The $^1H$ and $^{13}C$ NMR spectra of pyridine-type substrates, quinoline and isoquinoline, whose paramagnetic shifts are normally a composite of contact and dipolar contributions with single lanthanide shift reagents, show the feasibility of this approach.

• 정보저장시스템학회논문집
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• 제7권1호
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• pp.25-30
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• 2011

In the last couple of years, the flexible optical disk(FOD) system that consists of a thin polycarbonate(PC) film of 95 ${\mu}m$ thick, a rigid stabilizer, and a high speed spindle motor has been spot-lighted as the next-generation optical system for archival use of digital data. The air film between the rotating disk and stabilizer provides a means for damping out the lateral disk vibrations. However, its damping-capability drops significantly as the rotational speed of the disk exceeds a specific limit and, eventually, the disk vibration propagates inward causing the whole span of the disk exhibits large vibration amplitudes. Based on the numerical simulations as well as the experimental results, the present work aims to evaluate the damping coefficient of the air-film near the outer region of the disk where the capillary type orifices are applied to the edge of the curved stabilizer.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 춘계학술대회논문집
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• pp.316-322
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• 2002

This paper presents the temperature-dependent hysteresis identification of an electro-rheological (ER) fluid under various operating temperatures using the Preisach model. As a first step, polymethylaniline (PMA) particles are prepared and mixed with silicone oil to make an ER fluid. A couette type electroviscometer is then employed to obtain the field-dependent shear stress. In order to show the suitability of the Preisach model to predict a physical hysteresis phenomenon of the ER fluid, two significant properties; the minor loop property and the wiping-out property are experimentally examined under three dominant temperature conditions. Subsequently, the Preisach model fur the PMA-based ER fluid is identified using experimental first order descending (FOD) curves. The effectiveness of the identified hysteresis model is verified in the time domain by comparing the predicted field-dependent shear stress with the measured one under the both specified and unspecified temperatures. In addition, the hysteresis model proposed in this work is compared to Bingham model.

• 대한조선학회논문집
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• 제42권3호
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• pp.197-204
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• 2005

A waterjet propulsion system has many advantages compared with a conventional screw propeller especially for amphibious armored wheeled vehicles because of a good maneuverability at low speed, good operation ability at shallow water, high thrust at low speed to aid maneuverability and exit from water, etc. The POD type waterjet is adequate for the present wheeled vehicle because the weight is lighter and L/B is longer than the conventional armored amphibious vehicle. Resistance and self-propulsion tests with a 1/3.5-scale model are conducted at PNU towing tank. Based on these measurements, the performance is analyzed according to ITTC 96 standard analysis method and also according to the conventional propulsive factor analysis method. Based on these two methods, the full-scale effective and delivered powers of amphibious armored wheeled vehicle are estimated. This paper emphasizes the analysis method of model test of the waterjet propulsion system for a amphibious armored wheeled vehicle and the model test technique together with the comparison of the two analysis methods.