• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.839-850
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• 2002

A performance simulation program for the turboprop engine (PT6A-62), which is the power plant of the first Korean indigenous basic trainer KT-1, was developed for performance prediction, development of an EHMS (Engine Health Monitoring System) and the flight simulator. Characteristics of components including compressors, turbines, power turbines and the constant speed propeller were required for the steady state and transient performance analysis with on and off design point analysis. In most cases, these were substituted for what scaled from similar engine components'characteristics with the scaling law. The developed program was evaluated with the performance data provided by the engine manufacturer and with analysis results of GASTURB program, which is well known for the performance simulation of gas turbines. Performance parameters such as mass flow rate, compressor pressure ratio, fuel flow rate, specific fuel consumption and turbine inlet temperature were discussed to evaluate validity of the developed program at various cases. The first case was the sea level static standard condition and other cases were considered with various altitudes, flight velocities and part loads with the range between idle and 105% rotational speed of the gas generator. In the transient analysis, the Continuity of Mass Flow Method was utilized under the condition that mass stored between components is ignored and the flow compatibility is satisfied, and the Modified Euler Method was used for integration of the surplus torque. The transient performance analysis for various fuel schedules was performed. When the fuel step increase was considered, the overshoot of the turbine inlet temperature occurred. However, in case of ramp increase of the fuel longer than step increase of the fuel, the overshoot of the turbine inlet temperature was effectively reduced.

• 한국항공우주학회지
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• 제32권5호
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• pp.24-29
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• 2004

본 논문에서는 저속통제기로부터 비상 시 분리되는 외부연료탱크 및 LAU-131 로켓발사기의 분리안전성을 보이기 위하여 수행한 자유낙하 풍동시험, MSAP을 이용한 해석과 비행 시험의 연구결과를 종합하였다. 자유낙하형의 bomb rack을 사용하는 비행시험 중의 분리안 전성의 확인과 MSAP의 보정용 자료 생성을 위하여 수행한 아음속풍동을 이용한 자유낙하 시험의 결과에 대하여 기술하였다. 보정된 MSAP으로 자유낙하형과 사출형의 bomb rack 을 사용하였을 때의 분리안전성 해석을 수행하였다. MSAP 해석 결과를 이용한 상관관계 해석을 통하여 자유낙하형의 bomb rack을 사용할 경우의 투하 안전성도 보였다. 또한, 실기 비행시험을 통하여 투하시험을 수행하였으며 이를 해석결과와 비교하였다. 마지막으로, 풍동 시험, 해석결과 및 비행시험의 결과를 종합하여 저속통제기의 안전투하영역을 확정하였다.

• International Journal of Aeronautical and Space Sciences
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• 제15권4호
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• pp.345-355
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• 2014

This paper focuses on aerodynamic and inertial modeling of the propeller for its applications in flight dynamics analyses of a propeller-driven airplane. Unsteady aerodynamic and inertial loads generated by the propeller are formulated using the blade element method, where the local velocity and acceleration vectors for each blade element are obtained from exact kinematic relations for general maneuvering conditions. Vortex theory is applied to obtain the flow velocities induced by the propeller wake, which are used in the computation of the aerodynamic forces and moments generated by the propeller and other aerodynamic surfaces. The vortex lattice method is adopted to obtain the induced velocity over the wing and empennage components and the related influence coefficients are computed, taking into account the propeller induced velocities by tracing the wake trajectory trailing from each of the propeller blades. Aerodynamic forces and moments of the fuselage and other aerodynamic surfaces are computed by using the wind tunnel database and applying strip theory to incorporate viscous flow effects. The propeller models proposed in this paper are applied to predict isolated propeller performances under steady flight conditions. Trimmed level forward and turn flights are analyzed to investigate the effects of the propeller on the flight characteristics of a propeller-driven light-sports airplane. Flight test results for a series of maneuvering flights using a scaled model are employed to run the flight dynamic analysis program for the proposed propeller models. The simulations are compared with the flight test results to validate the usefulness of the approach. The resultant good correlations between the two data sets shows the propeller models proposed in this paper can predict flight characteristics with good accuracy.

• 한국항공운항학회지
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• 제17권2호
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• pp.62-67
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• 2009

LOSA is a flight safety program that analyses human errors in normal operations. Trained pilot observers monitor the normal flights at the observer seat. LOSA is a proactive non jeopardy data collection tool using threat and error management(TEM) as a framework. With the analysis of crew behaviors through LOSA with The LOSA collaborative(TLC), the airlines can identify the behaviors of the crew during normal operations. The major objective of LOSA is to measure how the crew manage threats, errors and undesired aircraft deviations in the cockpit on day to day operations. The airlines are able to set up effective TEM training with practical six generation Crew recourse management(CRM) with data of error from LOSA instead of theoretical CRM courses. The Airlines can use TEM as an integral part of a Safety Management System(SMS) and uses monitoring and cross-checking skills in the flight operations to manage threats and errors effectively when we know the errors we make in the cockpit on daily operation. The result of LOSA indicates that the error detection rate should be enhanced since around the half of the errors went undetected. The areas which should be focused for enhancing the error detection are monitor, cross-check, the management of workload, automation and taxiway/ runway to manage errors effectively.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.178-182
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• 2012

PEAT(Procedure/airspace Efficiency Assessment Tool)는 비행절차 및 공역 설계 프로그램을 이용하여 설계된 비행절차에 대해, 연료소모, 비행시간, 비행적합성, 소음분석 등의 효율성을 평가한다. 이 중 본 연구에서는 소음 분포 해석을 위한 INM(Integrate Noise Model)의 입력 자료를 생성하는 모듈을 설계하였다. 소음 분포 해석을 위한 INM 입력 파일은 항공기 기종, 소음 모델, 공항 환경, 활주로 트랙, 항공기 운항 횟수, 비행로 등에 관한 데이터를 담고 있어야 하며, 본래 파일 형태의 입력으로 구동하도록 설계되어 있지 않은 INM의 특성상 적절한 파일 형식을 만족시켜야 하는 구속조건 또한 뒤따른다. 따라서 입력될 데이터는 원래 주어진 확장성 마크업 언어(XML)에서 데이터베이스파일(DBF) 변환되도록 설계하였으며, 본 논문에서는 INM의 입력 자료를 제공하고 INM의 소음 분석 결과를 변환하여 저장하는 기능을 갖는 모듈의 설계 결과를 제시한다.

• 한국환경농학회:학술대회논문집
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• 한국환경농학회 2011년도 30주년 정기총회 및 국제심포지엄
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• pp.196-204
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• 2011

Abiotic stress is the primary cause of crop loss worldwide, reducing average yields for most major crop plants by more than 50%. In addition, future agricultural production and management will encounter multifaceted challenges from global climate change. Therefore, it is necessary to study the molecular response of crop plants to the stresses in order to develop appropriate strategies to sustain food production under adverse environmental conditions. We carried out a large scale proteomic analysis of soybean plants in response to various abiotic stresses, including drought, salinity, waterlogging and their interactions. Proteins were analyzed by two dimensional polyacrylamide gel electrophoresis followed by matrix-assisted laser desorption/ionization time of flight (MALDI-TOF) mass spectrometry. The identified proteins are involved in a wide range of cellular functions. In addition to the well known stress-associated proteins, we identified several novel proteins, which were not reported before. In many cases our proteomic data bridges the gap between mRNA and metabolite data. Our studie provides new insights into identification of abiotic stress responsive proteins in soybean, and demonstrates the advantages of proteomic analysis in dissecting metabolic and regulatory networks.

• 항공우주의학회지
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• 제30권1호
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• pp.34-39
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• 2020

The medical fitness of pilots is part of the civil aviation safety scenery. This study aimed to analyze the health problems occurring among Korean commercial pilots. Three data sources were used to identify the health problems: 7,574 aviation medical examination data, 5,400 sick leaves and 39 cases of a decrease in medical fitness during flight duty period and layover of Korean commercial pilots who have been working for K airline from Jan. 1, 2016 to Dec. 31, 2018. This study was retrospectively analyzed using SPSS 22 statistical program. Waiver of medical certificates was an average 11.9% of total issuance for 3 years, with a denial of 0.1%. The leading cause of denial of medical certificates was predominantly of cardiovascular cause (55.6%). Mild respiratory and digestive disease accounted for 82% of total sick prevalence and 68% of total sick days. The psychiatric and cardiovascular disease were ranked high according to the number of days lost per case. The most common cause of decrease in medical fitness during flight duty period was acute abdominal pain (36.4%) and musculoskeletal disorder (40%) when staying abroad. Aeromedical emphasis on minimizing cardiovascular risk remains appropriate. Major pilot health problems identified in this study should be considered in establishing pilot health promotion programs for aviation safety.

• 한국항공우주학회지
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• 제34권4호
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• pp.76-82
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• 2006

새로이 개발된 ALQ-X ECM 포드를 장착한 KF-16D 항공기의 플러터 해석을 수행하였다. 해석에 필요한 기체 고유진동모드 데이터를 지상진동시험 결과로써 직접 사용하는 방법을 제시하고 기존 자료를 이용하여 타당성을 확인하였다. 랜딩기어로 지지된 KF-16D 항공기에 대한 지상진동시험 결과를 비행 상태의 모달 데이터로 변환하였다. KF-16D 항공기에 ALQ-X를 장착한 형상과 기존의 ALQ-119 장착 형상에 대한 플러터 속도를 비교함으로써 새로이 개발된 ECM 포드를 기존의 ECM 포드와 동일한 비행영역에서 사용이 가능함을 입증하였다.

• 항공우주정책ㆍ법학회지
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• 제23권2호
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• pp.137-172
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• 2008

미국에서 자기비판적 분석의 법리에 의한 특권과 면제 이미 항공분야에서도 도입되고 있으나 일관성이 결여되어 있다. FDRs 프로그램은 FAA 또는 항공사에 의한 제제로 부터 공식적으로 보호되지는 아니한다. CVRs 프로그램의 경우 FAA는 집행조치를 위하여 그 데이터를 이용할 수 없으며 공개와 민사소송에서의 개시를 제한하고 있다. 따라서, CVRs은 FDR보다 높은 보호를 받고 있다. ASRS는 최초의 비자동적(non-self-disclosure) 보고시스템이며, 사고 또는 범죄에 관한 정보이외에는 FAA가 집행조치를 취할 수 없다. 다만, 비처벌 요건으로 규정하고 있는 "inadvertent and not deliberate)의 해석을 둘러싸고 FAA, NTSB 및 법원은 일관된 해석 기준이 없는 것으로 보이며, 데이터의 항공사의 징계조치에의 이용, 소송 당사자 또는 대중매체에의 공개 문제를 명확하게 다루고 있지 않다. 1990년대초 ASAP을 시범적으로 개시하였으며 FAA 집행조치 및 회사 징계조치로부터의 면제를 규정하고 있다. FOQA 프로그램은 1995년 시범프로그램을 통하여 최초로 시행되었으며 FAA 집행조치로 부터 면제되지만, 회사의 징계조치로부터의 면제에 대해서는 아무런 규정이 없다. 이러한 점은 ASAP와는 대비된다 할 수 있으며 노조협약에 의하여 FOQA 데이터에 근거한 회사의 징계조치를 배제시킬 수 있을 것이다. ASAP 및 FOQA의 데이터는 모두 2003년 FAA Order 8000.81에 의하여 공개되지 아니한다. 현재, ICAO의 움직임을 보더라도 국제사회에는 항공안전데이터를 보고한 자에 대한 보호의 강화에 대한 컨센서스가 형성되고 있으며 많은 국가들이 관련법을 시행하고 있다. 우리나라의 경우 현재, 항공법 제49조에 의하여 항공안전관리시스템을 도입하도록 되어 있다. 단계적으로 ASAP 또는 QOQA 등과 같은 프로그램의 입법화가 필요하다고 본다. 이와 더불어 미국에서와 같이 집행조치와 징계조치의 면제 규정 및 비공개 특권에 관하여 보다 구체적인 기준을 정하여 입법화하는 것도 필요할 것이다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 춘계 학술대회논문집
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• pp.27-34
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• 2004

In the Smart UAV Development Program, one of the 21c Frontier R&D Program, the tiltrotor has been studied as the concept of vehicle. The tiltrortor aircraft take-off and land in rotary wing mode like conventional helicopter, and cruise in fixed wing mode like conventional propeller airplane. For the conversion of the flight mode from helicopter to airplane, the nacelle located at wing tip has to be tilted from about 90 degrees of helicopter mode to about 0 degree of airplane mode. In this study, the aerodynamic characteristics of the wing with tilted nacelle is investigated using computation fluid dynamics technique. In order to feature out aerodynamic interferences between wing and nacelle, the flow calculations are conducted for the wing and the nacelle separately and for the combined geometry of wing and nacelle, respectively. Through this computations, not only the aerodynamic data-base for the wing-nacelle is constructed but also its contribution to the configuration design of the wing-nacelle is anticipated.