• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7C
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• pp.467-474
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• 2011

The performance of pilot-symbol-assisted channel estimation widely used for OFDM systems is degraded due to the small number of pilot symbols used for higher transmission efficiency. In this paper, we propose a pilot symbol based channel estimation using cross-correlation to improve the estimation performance of the OFDM system with small number of pilot symbols. The proposed technique detects a data symbol using the channel estimated by the pilot symbol and estimates the channel using the estimated data symbol and the pilot symbol. It is shown by computer simulations that the proposed technique outperforms the conventional pilot symbol assisted estimation technique.

• 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.

• Korean Chemical Engineering Research
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• v.52 no.2
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• pp.191-198
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• 2014

A semi-pilot hybrid system composed of a photocatalytic reactor and a biofilter was operated under various operating conditions in order to treat malodorous waste air containing both hydrogen sulfide and ammonia which are major air pollutants emitted from composting factories and many publicly owned treatment works (POTW). When both hydrogen sulfide and ammonia contained in malodorous waste air were treated simultaneously by a biofilter system, its performance of ammonia removal was much more poor than that by a biofilter system treating waste air containing only ammonia, unlike its performance of hydrogen sulfide removal. For semi-pilot hybrid system, the removal efficiencies of hydrogen sulfide and ammonia turned out to be ca. 83 and 65%, respectively. Therefore, for semi-pilot hybrid system, the removal efficiencies of hydrogen sulfide and ammonia was increased by ca. 4 and 30%, respectively, compared to those of semi-pilot biofilter system (control). In addition, the maximum elimination capacities of hydrogen sulfide and ammonia for semi-pilot hybrid system turned out to be ca. 60 and $37g/m^3/h$, respectively. These maximum elimination capacities of hydrogen sulfide and ammonia were estimated to be ca. 9.1% and ca. 23.3% greater than those for semi-pilot biofilter system (control), respectively. Therefore, the semi-pilot hybrid system contributed the enhancement of removal efficiency and the maximum elimination capacity of ammonia in a higher degree than that of hydrogen sulfide, compared to the semi-pilot biofilter system.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.1
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• pp.114-123
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• 2014

Due to the recent aircraft accidents both in Ethiopian airline and Malaysian airline, almost all the media are focusing the importance of the airline safety. Especially, media's eyes and ears are interested in the reasons why Malaysia airline's missing presumed as by either terrorist attack or pilot's mistake. Safety Behaviors of pilot are viewed as the most important human factor issues among researchers. This is because, if it were the case of a commercial airline, pilot's safety behavior would be directly related to the lives of couple of hundreds passengers. This paper considers the antecedents of this safety behaviors as pilot's leadership, pilot's leadership and self-efficacy. This paper has tried to find out which human factors of a pilot would have significant impact on their safety behaviors. According to the empirical research result from SEM (Structural Equation Model), it was found out both the leadership and self-efficacy of a pilot had direct impact on their safety behaviors through safety motivation. Thus it could be concluded that flight crew must follow the instruction of a pilot who had the authority of the flight operation. The managerial implication are discussed in the conclusion part of this paper. As an implication, this paper concluded that it would be necessary to do further research on pilot's leadership and self-efficacy.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.965-970
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• 2010

Because of a large number of subcarriers, the high PAPR(Peak-to-Average Power Ratio) is the major drawback of NC-OFDM system used for wireless communication system. Comb type pilot assignment is more efficient and lower computational complexity for the channel estimation than the block type pilot. However, even if the CAZAC(Constant Amplitude Zero Autocorrelation) matrix transform is used for the PAPR reduction of the data symbols, PAPR increases when the pilot is inserted in comb type with the data symbols. Therefore, in this paper, we additionally use a new SLM technique in order to lower the PAPR again even in the comb type pilot. Also, a new SLM technique suggested in this paper does not need any additional bandwidth for sending selection information for SLM. This combined method has good PAPR reduction performance and efficient data transmission.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.29 no.2
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• pp.117-121
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• 2021

Multi-crew Pilot License (MPL) is an international pilot certification adopted by the International Civil Aviation Organization (ICAO) in 2006 under the recognition of the need for efficient and systematic pilot training including the education of pilots with advanced aviation technology and ability to respond to flight environment, resolution of the human factor problems of pilots, and provision of stable training tools for transport aircraft pilots for potential risk of pilot shortage in the future. South Korea also has prepared a legal basis for operating an MPL system in the Aviation Act in 2009, but there has been no domestic MPL qualifier. The biggest reason for this seems to be the insufficient domestic MPL training system. Therefore, it is necessary to benchmark the international standards of the ICAO, and to promote the development of the Korean MPL training system through revision and supplementation of laws and regulations in consideration of Korean circumstances.

• Journal of IKEEE
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• v.2 no.1 s.2
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• pp.85-95
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• 1998

We consider two methods for the pilot signal transmission in DS/CDMA systems: Pilot channel method which is parallel to the data channel and pilot symbol method which is serial to the data channel. In this paper, we analyze the two methods. The performance of the two methods is shown to be dependent upon the added noise, fading, pilot symbol period and pilot channel power. Through the analysis, it is found that the performance of the pilot symbol method outperforms compared to the pilot channel method.

• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.428-428
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• 2005

• Journal of the Korean Society for Aviation and Aeronautics
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• v.26 no.2
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• pp.31-38
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• 2018

The pilot aptitude test so far has been conducted with a dichotomous concept of cognitive factor and non-cognitive factor, so it was not easy to explain concrete factors about pilot aptitude. Therefore, an integrated approach is needed to construct pilot aptitude test including all factors that can predict pilot aptitude. In previous study, we developed questionnaire items for the Pilot Aptitude Personality Test(PAPT) which can predict the flight training achievement through personality and personal characteristics. And those items were categorized as personality, cognition, and motivation factors. The flight training grades were correlated with all the test factors of the items, and the cognitive factors were high. As a result of the regression analysis, the total score of the three factors together accounted for 16% of the flight training grades. The results of the ANOVA showed that the cognition factors and motivation factors had significant effects on the completion of the flight training. The factors of PAPT predicted not only the completion of the flight training but also the flight performance. This is because the existing paper-pencil pilot aptitude test can only discriminate the flight training completion status. This is also a result of the fact that the introductory flight training consists of various factors including not only basic cognition but also personality and motivation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.6A
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• pp.660-666
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• 2004

Transmitted data may be compensated by using estimated channel values that are obtained with pilot symbols in OFDM-CDMA systems. Generally, a USE (Minimum Mean-Squared Error) estimator using correlations between pilot symbols gives good results, but its structure is so complicated. Starting with a modification of PA (Pilot-Aided) algorithm using pilot symbols and PADD (Pilot-Aided Decision-Directed) algorithm using both pilot and data symbols, a new channel estimation algorithm with more simpler structure is proposed. The performance of this algorithm is evaluated with varying mobile speed in a Ralyleigh multipath fading environment through computer simulations. The simulation results show that the proposed channel estimation algorithm outperforms a conventional PA algorithm.