• 대한영상의학회지
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• 제85권2호
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• pp.345-362
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• 2024

자기공명영상(이하 MRI)은 복부 영상에서 국소 병변의 감지와 특성을 찾을 수 있는 것 때문에 중요한 역할을 한다. 그러나 MRI 검사에 상대적으로 긴 검사 시간과 호흡 유지 기법에서 움직임 관리와 같은 몇 가지 힘든 요인이 있다. 최근에는 검사 시간을 줄이면서 적절한 이미지 품질을 유지하는 기법인 평행 이미징, 압축 감지(compressed sensing) 및 최첨단 딥 러닝(deep learning) 기술이 등장하여 문제 해결 전략을 가능하게 하고 있다. 또한, 역동적 조영증강 영상에서 자유 호흡 기법은, 추가 차원(extra-dimensional)-부피 보간 호흡 유지 검사(volumetric interpolated breath-hold examination) 및 황금 각도 방사형 희소 병렬(golden-angle radial sparse parallel), 간 가속 볼륨 획득(liver acceleration volume acquisition) 스타와 같은, 심한 호흡곤란이나 마취 중인 환자에게서 복부 MRI를 시행하는 것을 돕는다. 이 임상화보에서는 시간을 줄이면서도 이미지 품질을 유지하기 위한 다양한 고급 복부 MRI 기술과 역동적 영상을 위한 자유 호흡 기술을 제시하고 또한 이를 통한 예시들을 보여주고자 한다. 이러한 첨단 기법들의 고찰은 적용된 시퀀스의 적절한 해석에 도움을 줄 것이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1434-1439
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• 2011

The purpose of this study is based on the optimize the system life cycle cost apply to the advanced systems engineering techniques consideration thought to the system life cycle for the power system which is the one of the major component of the light rail transit system. Generally, the systems engineering techniques apply to the LRT's power systems are not optimize the whole life cycle cost of the power systems because systems engineering management activities are concentrate in performing the key-technology oriented at the construction stage of the dedicated power systems for light rail transit. Through this study, All the stakeholders can be utilize a this advanced systems engineering techniques which is fully considered the life cycle cost through the considering in whole system life cycle (such as concept, design, operation, maintenance and dispose stage as well as construction stage) and adopted by KSX ISO/IEC 15288 system life cycle processes.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권1호
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• pp.33-41
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• 2003

In this work, process optimization techniques for high frequency performance of HBTs are presented. The techniques are focused on reducing parasitic base resistance and base-collector capacitance, which are key elements determining the high frequency characteristics of HBTs. Several fabrication techniques, which can significantly reduce the parasitic elements of the HBTs for improved high frequency performance, are proposed and verified by the measured data of the fabricated devices.

• International Journal of Aeronautical and Space Sciences
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• 제12권4호
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• pp.371-378
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• 2011

In this paper, the wavelet denoising techniques using thresholding method are applied to the low cost micro electromechanical system (MEMS)-global positioning system(GPS) integrated system. This was done to improve the navigation performance. The low cost MEMS signals can be distorted with conventional pre-filtering method such as low-pass filtering method. However, wavelet denoising techniques using thresholding method do not distort the rapidly-changing signals. They can reduce the signal noise. This paper verified the improvement of the navigation performance compared to the conventional pre-filtering by simulation and experiment.

• Journal of Advanced Marine Engineering and Technology
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• 제24권4호
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• pp.393-404
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• 2000

• JSTS:Journal of Semiconductor Technology and Science
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• 제9권4호
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• pp.257-265
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• 2009

Recent progress in development of CMOS power amplifiers for mobile terminals is reviewed, focusing first on switching mode power amplifiers, which are used for transmitters with constant envelope modulation and polar transmitters. Then, various transmission line transformers are evaluated. Finally, linear power amplifiers, and linearization techniques, are discussed. Although CMOS devices are less linear than other devices, additional functions can be easily integrated with CMOS power amplifiersin the same IC. Therefore, CMOS power amplifiers are expected to have potential applications after various linearity and efficiency enhancement techniques are used.

• 동력기계공학회지
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• 제15권1호
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• pp.18-23
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• 2011

Image processing has provided powerful techniques to extract from the acoustic signals the desired information on evaluation for leakage existence, leakage rate, and searching for leakage location, etc. The imagery NDE data available can add additional and significant dimension in nondestructive evaluation(NDE) information and thus for exploiting in applications. To extract such information the use of advanced image processing techniques is much needed. In recent years, there has been much increased use of acoustic signal image processing techniques in acoustic NDE. This approach will increase the efficiency of inspection procedures and reduce inspection time. In this paper we are concerned only with This paper is concerned mainly with the use of advanced image processing techniques in valve leakage detection and advanced image restoration and enhancement methods, which attempt to evaluate promptly by a visualization method the acoustic sources while detecting the valve leakage.

• 영어어문교육
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• 제12권1호
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• pp.103-129
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• 2006

This paper presents a case study of the effectiveness of debate class in promoting speaking skills of advanced learners. The researcher adopted English debate techniques in an English speaking class during four-week teacher training program and investigated how teachers responded to the new technique. Forty-five middle and high school teachers participated in the study and classroom observation, pre-survey, post-survey, and focus group interviews were used as the major research methods. The teacher pre-survey results presented that teachers prefer a conversation class where they can directly acquire proper sentence patterns and speaking strategies rather than spend time in performing communicative events. The results of the focus group interview and post-survey confirmed that a debate class can meet this specific teachers' needs. Most teachers responded positively to the debate classes since: 1) debate techniques are relatively new ideas to Korean teachers; 2) debate techniques require speed and accuracy in speech; thus teachers could learn to present their ideas logically and efficiently in a limited time through repeated argument exercises. The study result implies that debate technique can be an effective vehicle in an EFL context to promote advanced learners' logical thinking skills and logical English sentence structures.

• 비파괴검사학회지
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• 제23권6호
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• pp.616-621
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• 2003

There are various Non-Destructive Evaluation (NDE) techniques used for measurement of residual stresses in material, such as magnetic methods, X-ray diffraction, Ultrasonic velocity measurement etc. The capabilities, applications and limitations of these techniques for evaluation of cold work/plastic deformation were studied and compared. Mild steel plates were subjected to different degree of cold deformation and were analyzed by Magneto-mechanical Acoustic Emission (MAE), Barkhausen Noise (BN) and magnetic properties (hysteresis loop parameters analysis). Further, these specimens were analyzed by X-ray diffraction and ultrasonic velocity measurements. The microhardness measurement and microstructure studies of these cold worked plates were also carried out. The results of all these studies and comparison of different techniques are discussed in this paper.

• 한국전자거래학회:학술대회논문집
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• 한국전자거래학회 2004년도 e-Biz World Conference
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• pp.239-250
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• 2004

The preference of customers change as time goes by. The existing Collaborative Filtering (CF) techniques has no room for including this change yet, although these techniques have been known to be the most successful recommendation technique that has been used in a number of different applications. In this study, we proposed a new methodology for enhancing the quality of recommendation using the customers' dynamic behaviors over time. The proposed methodology is applied to a large department store in Korea, compared to existing CF techniques. Some experiments on the real world data show that the proposed methodology provides higher quality recommendations than other CF techniques, especially better performance on heavy users.