• Journal of the Korean Society of Systems Engineering
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• v.16 no.1
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• pp.51-57
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• 2020

The fighter pilot uses radar mounted on the fighter to obtain high-resolution SAR (Synthetic Aperture Radar) images for a specific area of distance, and then the pilot visually classifies targets within the image. However, the target configuration captured in the SAR image is relatively small in size, and distortion of that type occurs depending on the depression angle, making it difficult for pilot to classify the type of target. Also, being present with various types of clutters, there should be errors in target classification and pilots should be even worse if tasks such as navigation and situational awareness are carried out simultaneously. In this paper, the concept of operation and functional structure of radar system for fighter jets were presented to transfer the SAR image target classification task of fighter pilots to radar system, and the method of target classification with high accuracy was studied using the CNN ensemble model to archive higher classification accuracy than single CNN model.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.772-775
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• 1992

It is necessary to estimate hydrodynamic coefficients to design the auto-pilot system and motion simulator of submersible vehicle. In this paper, an algorithm was designed to estimate hydrodynamic coefficients of submersible vehicle. Using this algorithm, the hydrodynamic coefficients were estimated from measurements of full scale trial. The estimated hydrodynamic coefficients were used for the design of an auto-depth controller(ADC) of submersible vehicle, and the resulting ADC are proved to have a better performance than the previous one.

• 한국연소학회:학술대회논문집
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• 2003.05a
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• pp.27-32
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• 2003

Diesel-Fueled HCCI(Homogeneous Charge Compression Ignition) Engine is an advanced combustion process explained as a premixed charge of diesel fuel and air is admitted into the cylinder and compression ignited. It has possibility to reduce NOx by spontaneous auto-ignition at multiple points that allows very lean combustion resulting in low combustion temperatures. Also PM could be reduced by the premixed combustion and no fuel-rich zones. But HCCI couldn't be realized because of the difficulties in vaporizing the diesel, control of combustion phase directly. To solve these problems, new fuel injection strategy, explained as the pilot fuel injection to promote ignition near TDC following the main fuel injection at the extremely advanced timing, is applied during the compression ratio is varied from 18.9:1 to 27.7:1 This is not a pilot fuel to promote the ignition but also the direct control method of the combustion phase. Experimental result shows the pilot fuel injection promote the ignition and the compression ignition of the HCCI engine is achieved as compression ratio becomes higher. Also there is an optimal pilot fuel injection timing for the HCCI combustion. NOx is reduced more than 90% compared to DI-Diesel case but PM and THC emission needs more investigation.

• 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 Korean Neurosurgical Society
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• v.61 no.3
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• pp.393-401
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• 2018

The prognosis of brain tumors in children has improved for last a few decades. However, the prognosis remains dismal in patients with recurrent brain tumors. The outcome for infants and young children in whom the use of radiotherapy (RT) is very limited because of unacceptable long-term adverse effect of RT remains poor. The prognosis is also not satisfactory when a large residual tumor remains after surgery or when leptomeningeal seeding is present at diagnosis. In this context, a strategy using high-dose chemotherapy and autologous stem cell transplantation (HDCT/auto-SCT) has been explored to improve the prognosis of recurrent or high-risk brain tumors. This strategy is based on the hypothesis that chemotherapy dose escalation might result in improvement in survival rates. Recently, the efficacy of tandem HDCT/auto-SCT has been evaluated in further improving the outcome. This strategy is based on the hypothesis that further dose escalation might result in further improvement in survival rates. At present, the number of studies employing tandem HDCT/auto-SCT for brain tumors is limited. However, results of these pilot studies suggest that tandem HDCT/auto-SCT may further improve the outcome. In this review, we will summarize our single center experience with tandem HDCT/auto-SCT for recurrent or high-risk brain tumors.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.28 no.4
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• pp.69-81
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• 2020

Since airline safety depends significantly on the role of pilot, the importance of airlines' training qualified pilots and investing in the training program grows. This study aims to analyze the determinants of the commercial airline pilot competencies during the transition course. To this purpose, one-year training evaluation results of 215 new airline pilots in the JET transition course of Company K in 2019 are studied with correlation coefficient analysis, factor analysis, ANOVA, and regression analysis. Undergraduate major and Uljin-trained pilots show higher final-stage scores in PROC, AUTO, and CRM. Due to Uljin-trained pilots' higher first-stage scores, their score increase during the course is limited. Uljin-trained pilots' MANUAL scores in the final stage are lower than those of undergraduate major and overseas-trained pilots. Influence of trained location is found greater than English competency, undergraduate GPA, and ground school scores on commercial airline pilot competency evaluation scores during the program. The results will be useful in establishing scenario-based training focusing on different background to apply competency-based training and assessment.

• Language and Information
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• v.7 no.1
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• pp.23-40
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• 2003

In this paper, we have proposed Auto-TUS, an automatic transcription module of three union symbols-hyphen, dash and tilde (‘­’, ‘―’, ‘∼’)-using their linguistic contexts. Few previous studies have discussed the problems of ambiguities in transcribing symbols into Korean alphabetic letters. We have classified six different reading formulae of the union symbols, analyzed the left and right contexts of the symbols, and investigated selection rules and distributions between the symbols and their contexts. Based on these linguistic features, 86 stereotyped patterns, 78 rules and 8 heuristics determining the types of reading formulae are suggested for Auto-TUS. This module works modularly in three steps. The pilot test was conducted with three test suites, which contains respectively 418, 987 and 1,014 clusters of words containing a union symbol. Encouraging results of 97.36%, 98.48%, 96.55% accuracy were obtained for three test suites. Our next phases are to develop a guessing routine for unknown contexts of the union symbols by using statistical information; to refine the proper nouns and terminology detecting module; and to apply Auto-TUS on a larger scale.

• Transactions of the Korean Society of Automotive Engineers
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• v.4 no.1
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• pp.155-164
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• 1996

Dual-fuel engines are being researched with emphasis on the possible types of natural gas supply systems. Hence, a three-dimensional combustion model by using finite volume method was developed to provide a fundamental understanding of the auto-ignition of pilot distillate and subsequent burning of natural gas, when the natural gas as well as the distillate was directly injected into a quiescent diesel engine like combustion bomb tests and the numerical results were investigated for the mixed combustion phenomena. With high-pressure natural gas injection, it was found that the gaseous fuel injection characteristics had to be well harmonised with that of the pilot distillate. For better combustion efficiency, however, further researches are required for the optimisation of injection system in the existence of air motion.

• Journal of the Korea Society of Computer and Information
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• v.9 no.1
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• pp.63-70
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• 2004

This paper describes modeling, design and performance test results of infrared thermal image target system which can generate infrared thermal image on aircraft. The system is designed to control image shape and intensity so that the infrared image shape and its emitting intensity are so similar to that of real aircraft. When applying the technique suggested in this paper, the system consumes only small electric power energy about 30(㎾) to generate infrared thermal image which is equivalent to that of real aircraft under full power operation. After verifying performance test, the system developed here has been used as a target for korean potable surface to air missile(KPSAM) at the stage of evaluation test such as target adaptive guidance test and auto-pilot logic test.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.40 no.2
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• pp.144-148
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• 2004

Generally a ship in a port or canal is guided by tugboat(s), while the ship engine(s) and steering mechanism idle. The shortcomings of this method are insufficient in course keeping ability, danger of collision with waterside structures, time-consuming preparation for tugging, as well as the need to maintain tugboats. A new technology for ship guiding, based on the physical principle of interaction of a solid body with aerated liquids has been developed [1]. Model tests were carried out for the verification of system at slow speed by engine operating conditions and with an idle steering. The developed device has been proved to keep the ship on course safely.