• 한국통신학회논문지
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• 제22권3호
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• pp.571-579
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• 1997

There are some transmission types on the reverse link of wideband DS-CDMA cellular system. The configurations of logical channels on the reverse link may be different dependent upon the transmission methods of reverse pilot or control signaling. In this paper, we present three transmission types on the wideband DS-CDMA reverse link; no-pilot system, pilot-channel aided system and pilot-symbol aided system. And we compare the performance of three systems in terms of capacity and cell coverage. The pilot-symbol aided system is shown to have the better performance than the pilot-channel aided system in both capacity and cell coverage.

• 한국항공운항학회지
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• 제26권4호
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• pp.129-141
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• 2018

In this paper, two different flight training devices were constructed to verify the effectiveness of a pilot training system based on a Virtual Reality Head Mount Display. VFR Flight Procedure and IFR Flight Procedure were conducted by high level pilots with Commercial Pilot Licence. Flight data and pilot's visual data for each flight procedure were extracted, compared and analyzed with two training systems. Finally, the effectiveness of the training systems based on the VR HMD was demonstrated by assessing the given mission and the flight results.

• 한국연소학회:학술대회논문집
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• 대한연소학회 2003년도 제27회 KOSCO SYMPOSIUM 논문집
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• pp.251-256
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• 2003

The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors, solenoid-driven and piezo-driven type, with different electric driving characteristics So, three common-rail injectors with different electric current wave were used in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. Also the CFD analysis was carried out for fuel behavior under high pressure in between needle and nozzle of solenoid-driven injector to know the condition of initial injection at experiment test. It was found that pilot injection of common-rail system was effected by rate of injection and temperature of injected fuel and electrical characteristic of the driven injector.

• 한국항공운항학회지
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• 제13권3호
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• pp.43-60
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• 2005

In september 2004, a new pilot certificate scheme referred to as Sport Pilot Certificate was declared official and standardized in the US. The designation of Light-sport aircraft and the details of the relevant pilot certificate policy was announced out of the perception that a new regulation is required to be applied whereby the limitations on the manufacturing process enhancements and current aviation rules are considered the triggering factors. US Federal Aviation Regulation retains a comprehensive range of airworthiness certificates and aircrafts are managed systematically in accordance with FAR 21, 103. The airworthiness are further segregated into sub categories, which allows differentiated management. Korean Aviation Law classify aircraft into five different categories and powered air vehicle that weighs more than 150kg(19liters fuel capacity) for one seat, 225kg for two seats(38liters fuel capacity) while the systems that fall under a specific mass threshold level are known as ultralight vehicle. The research discusses the policy of the sport pilot certificate and the light-sport aircraft ratings announced official by the Federal Aviation Administration in an intuitive fashion with the analysis of the operations providing the evidence as to the viability of adopting the policy in local grounds. Based on the findings, the report discusses the case for introducing the light-sport aircraft and make recommendation on a strategy of applying the policy in Korea with respect to the pilot certificates, safety agenda, and the written test for the pilot certificate, and operating efficiency.

• 한국항공운항학회지
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• 제28권3호
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• pp.41-51
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• 2020

This research is accomplished to verify objectively how flight instructor's transformative leadership affects student pilot's psychological stabilities and learning satisfactions. Flight instructor's transformative leadership factor divided into individual consideration, intellectual stimulus and charisma from exploring factor analysis. Psychological stability factor subdivided into happiness, concentration and satisfaction. Learning satisfaction factor subdivided into participation, recommendation, persistence, accomplishment and relationship. According to the analysis of flight instructor's transformative leadership effect on psychological stability, it showed that it has statistical significance on happiness, concentration and satisfaction. It also has positive influence on happiness and concentration. The result from regression analysis showed that individual consideration and charisma affected happiness and concentration in order. However, satisfaction from individual consideration, intellectual stimulus and charisma didn't show statistical significance to student pilot's satisfaction. Analysis of flight instructor's transformative leadership on student pilot's learning satisfaction showed statistical significance between them. Intellectual stimulus and charisma had positive influence on student pilot's learning satisfaction. Regression analysis showed charisma and intellectual affect student pilot's learning satisfaction in order.

• Journal of the Korean Wood Science and Technology
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• 제19권3호
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• pp.27-34
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• 1991

Screw withdrawal test was carried out on the face and edge of domestic particleboard and medium density fiberboard in order to evaluate optimum pilot hole diameter. The obtained results were as follows: 1. Maximum withdrawal strengths on the face and edge of particleboard were obtained with pilot hole diameters at about 50% of root diameters of screw. 2. Maximum withdrawal strength on the face and edge of medium density fiberboard were obtained with pilot hole diameters that were about 60% and 50% of root diameters of screw, respectively. 3. Withdrawal strength showed about 91% of maximum withdrawal strength when pilot holes were not pre bored at particleboard. but when pilot holes at 90% of root diameter of screw withdrawal strength showed about as 51.3% of maximum withdrawal strength. 4. Withdrawal strength showed about 88% of maximum strength when pilot holes were not used, but withdrawal strength indicated 55.4% of maximum strength in case of 90% of root diameters of screw. 5. Maximum withdrawal strength on the face of particleboard was about 70.5% higher than that of the edge, and however medium density fiberboard was about 19.6% higher than that of the edge.

• 한국가스학회지
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• 제7권3호
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• pp.18-23
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• 2003

한국에서의 LNG에 대한 수요는 처음 수입된 1986년 이후로 크게 증가하고 있다. 따라서 LNG 소비에 맞추어 LNG 저장탱크의 확충이 요구된다. 그러나 LNG 저장 설비에 대한 설계, 건설 그리고 분석 분야에서는 유체-구조의 상호 작용과 LNG의 저온 특성 때문에 고정도의 선진 기술이 요구된다. 최근 한국가스공사에서는 Pilot LNG 저장탱크를 건설하였으며 실제 운전을 통한 핵심 기술을 개발하여 축척하고 있다. 한 부분의 연구로서 기초 동특성 시험을 실시하였다. 본 연구에서는 동특성 실험을 수행하였으며, Pilot LNG 저장탱크에 대한 동특성을 검증 및 분석하였다.

• 한국항공운항학회지
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• 제24권4호
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• pp.62-69
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• 2016

The purpose of this study is to develop questionnaire items for the Pilot Aptitude Personality Test(PAPT) which can predict the flight training achievement through personality and personal characteristics. To do this, we investigated the personality traits required to successfully conduct flight training for 30 flight instructors as a subject. The results were as follows: motivation, concentration, concentration, situational awareness, and concentration. Based on this, preliminary 300-item questionnaire was prepared by combining the existing studies related to pilot aptitude. Survey was conducted using preliminary questionnaire for 152 student pilots as a subject. As a result of the correlation analysis between the results of the questionnaire and the flight training, 16 questions were derived. Finally, factor analysis showed that the final 14 questionnaire items were confirmed. The internal concept of an item is categorized as personality, perception, and motivation. This study suggests that the pilot aptitude should be viewed from an extended point of view by analyzing individual characteristics and pilot aptitude in relation to flight training achievement.

• 한국통신학회논문지
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• 제34권11C호
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• pp.1113-1121
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• 2009

본 논문에서는 기지국간 간섭이 큰 다중기지국 환경에서 multiple-input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) 시스템을 위한 파일럿 시퀀스 설계 방법 및 채널 추정 기법을 제안한다. 제안 파일럿 시퀀스의 경우 평균 제곱 오류치 (Mean Square Error)를 최소화시키며, 설계된 파일럿에 적합한 채널 추정 방법을 제안한다. 제안된 파일럿 시퀀스 및 채널 추정 기법은 추 시퀀스의 상관관계 특성을 이용해 설계되며 모의실험을 통해 설계된 파일럿 시퀀스를 이용한 채널 추정 기법이 기지국간 간섭을 완화에 효과적임을 보여준다.

• 한국추진공학회지
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• 제5권3호
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• pp.19-24
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• 2001

대기중에서 움직이는 비행체(항공기, 미사일 등)의 속도 및 고도를 측정하기 위한 장치가 피토관 (Pilot-Tube)이다. 고속으로 비행하는 항공기의 안전하고 효율적인 운항을 위해서는 정확한 비행속도 및 고도측정이 요구된다. 피토관 최적 설계인자 결정을 위해 피토관 Nose의 Inlet부, Nose부 외곽형 상, 정압홀의 형상 및 정압홀 설치 위치 선정을 위한 유동장 해석을 수행하였다. 또한 해석을 통해 얻은 설계자료를 기본으로 제작한 피토관의 풍동실험을 수행하였다. 본 연구를 통해 속도 및 고도 계측용 피토관의 설계기술을 확보하였고 제작기술을 보유하였으며, 유동해석 및 풍동실험을 함으로써 피토관 국산화에 필요한 기본 자료를 얻었다.