• Journal of the Korean Society for Aviation and Aeronautics
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• v.22 no.1
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• pp.15-21
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• 2014

Modern aircraft air navigation has been changed from the conventional air navigation aid to utilizing Global Navigation Satellite System. For the air navigation of fast moving aircraft, GNSS required extremely high accuracy and reliability. This study reviews the basic concept of Satellite Based Augmentation System which is discussed in the International Working Group of International Civil Aviation Organization and status of some SBAS leading State's case. In addition to that, a progress of SBAS development and implementation in the Republic of Korea was reviewed with pointing out of general hurdles and counter measures.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.11
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• pp.991-996
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• 2011

This study was carried out vibration attenuation of vibration absorber attached to the cantilever beam structure. Modern tank guns are stabilized to allow fire on the move while traversing uneven terrain. However, as the length of the barrel is extended, to meet required muzzle exit velocities, the terrain induced vibrations lead to increased muzzle pointing errors. Thus, reducing these vibrations should lead to increased accuracy. The vibration absorber includes a compliant energy storage device, such as a spring, and a mass secured to the energy storage device. In this study, it accomplished a research in about gun barrel vibration attenuation using tuned mass damper. The barrel was hung from a bungee cord for free-free condition. It accomplished a vibration experiment for verified attenuation efficiency.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10a
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• pp.504-509
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• 1993

A heavy load driving system for the gun laying control is designed with the analysis of performance in pointing accuracy and speed. To eliminate the firing noise and high frequency system noise, a .PI. filter is implemented in conjunction with the PI velocity control. To incorporate the gunner's commands in the PID position control loop easily, a .mu.-processor is utilized in the position control loop. Main difficulties in the heavy load driving system exist in the design of motor drivers and heat sinkers. With an appropriate design of the motor drivers and heat sinkers, the performance of the gun laying system is analyzed by the simulation.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.1
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• pp.35.4-36
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• 2017

A 250 kton water Cherenkov detector is proposed to be built in Korea to determine the CP violation phase and the neutrino mass ordering using a neutrino beam produced in J-PARC of Japan. It will be also a world-leading neutrino telescope to reveal the mystery of supernova explosion by observing a neutrino burst. The telescope is expected to detect more than 100,000 neutrinos in ten seconds from a supernova explosion in our Galaxy. The pointing accuracy will be better than 1 degree and be able to guide early optical telescope observations. The expected rate of supernova explosion in our galaxy is once per every 30 years in the most optimistic case or once per every 100 years in the worst case. If it is indeed observed, it will be a historical chance to study the supernova explosion mechanism in great details. In this talk, various astronomy potentials will be discussed if the Korean neutrino observatory is built.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.627-632
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• 2011

This study was carried out vibration attenuation of vibration absorber attached to the cantilever beam structure. Modern tank guns are stabilized to allow fire on the move while traversing uneven terrain. However, as the length of the barrel is extended, to meet required muzzle exit velocities, the terrain induced vibrations lead to increased muzzle pointing errors. Thus, reducing these vibrations should lead to increased accuracy. The vibration absorber includes a compliant energy storage device, such as a spring, and a mass secured to the energy storage device. In this study, it accomplished a research in about gun barrel vibration attenuation using tuned mass damper. The barrel was hung from a bungee cord for free - free condition. It accomplished a vibration experiment for verified attenuation efficiency.

• Ocean Systems Engineering
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• v.7 no.4
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• pp.319-328
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• 2017

Higher prediction efficacy is a very challenging task in any field of engineering. Due to global warming, there is a considerable increase in the global sea level. Through this work, an attempt has been made to find the sea level variability due to climate change impact at Haldia Port, India. Different statistical downscaling techniques are available and through this paper authors are intending to compare and illustrate the performances of three regression models. The models: Wavelet Neural Network (WNN), Minimax Probability Machine Regression (MPMR), Feed-Forward Neural Network (FFNN) are used for projecting the sea level variability due to climate change at Haldia Port, India. Model performance indices like PI, RMSE, NSE, MAPE, RSR etc were evaluated to get a clear picture on the model accuracy. All the indices are pointing towards the outperformance of WNN in projecting the sea level variability. The findings suggest a strong recommendation for ensembled models especially wavelet decomposed neural network to improve projecting efficiency in any time series modeling.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.6_spc
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• pp.744-754
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• 2016

A large satellite communication terminal on the truck shall be designed ruggedly against a disturbance for holding a position which satisfies communication performance. Especially. A design considering a wind is essential for getting into a communication with a satellite in a strong-wind condition. This paper suggests a experimental method to analyze performance of a radio wave and the aiming accuracy by wind vibration. And it analyzes the improvement and vibrational effect on a random-excitation of a structure caused by nonlinear strong wind.

• Journal of Korea Multimedia Society
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• v.24 no.4
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• pp.528-537
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• 2021

Face recognition has gained significant notice because of its application in many businesses: security, healthcare, and marketing. In this paper, we will present the recognition method using the combination of correlation filters (CF) and Support Vector Machine (SVM). Firstly, we evaluate the performance and compared four different correlation filters: minimum average correlation energy (MACE), maximum average correlation height (MACH), unconstrained minimum average correlation energy (UMACE), and optimal-tradeoff (OT). Secondly, we propose the machine learning approach by using the OT correlation filter for features extraction and SVM for classification. The numerical results on National Cheng Kung University (NCKU) and Pointing'04 face database show that the proposed method OT-SVM gets higher accuracy in face recognition compared to other machine learning methods. Our approach doesn't require graphics card to train the image. As a result, it could run well on a low hardware system like an embedded system.

• Journal of Information Processing Systems
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• v.18 no.3
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• pp.344-358
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• 2022

Text summarization is the task of producing a shorter version of a long document while accurately preserving the main contents of the original text. Abstractive summarization generates novel words and phrases using a language generation method through text transformation and prior-embedded word information. However, newly coined words or out-of-vocabulary words decrease the performance of automatic summarization because they are not pre-trained in the machine learning process. In this study, we demonstrated an improvement in summarization quality through the contextualized embedding of BERT with out-of-vocabulary masking. In addition, explicitly providing precise pointing and an optional copy instruction along with BERT embedding, we achieved an increased accuracy than the baseline model. The recall-based word-generation metric ROUGE-1 score was 55.11 and the word-order-based ROUGE-L score was 39.65.

• Advances in aircraft and spacecraft science
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• v.5 no.4
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• pp.459-475
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• 2018

In the field of aerospace engineering, accurate control of a spacecraft's orientation is often very important to mission success. Therefore, attitude control is a technically plentiful and extensively studied subject in controls literature during recent decades. This investigation of spacecraft attitude control is assumed to address two important aspects of the problem solutions. One sliding mode anti-disturbance control for utilization of faulty actuator components and another one disturbance observer based control to improve the pointing accuracy in the absence of anti-vibration equipment for the elastic appendages like a solar panel. Simultaneous occurrence of vibration due to flexible appendages and reaction degradation due to failure in attitude actuators complicates this case. The advantage of this method is acquisition proper control by the combination of disturbance observer and sliding mode compensation that form a fault tolerant control for the concerned satellite attitude control system. Furthermore, the proposed composite method indicates that occurrence the failure in actuators and even elastic solar panel vibration effect may be handled directly without reconfiguring the control components or providing piezoelectric devices. It's noteworthy, attitude quaternion and angular velocity commands are robustly tracked via controllers to become inclined to zero.