• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제55권12호
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• pp.653-660
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• 2006

In this paper, dynamic simulation results for modules of a magnetically-levitated(Maglev) vehicle are presented. The mathematical dynamic models for the Maglev vehicle are firstly derived. The Maglev system consists of one vehicle, two half-bogies, one guideway, four secondary suspensions, eight electromagnets and levitation control systems. Also, the dynamic characteristics are analysed by using the derived models. Finally, two simulations such as reference airgap step change of 1mm and rail step change of 1mm, are carried out. The dynamic simulation results are shown to testify the developed dynamic simulation program. From the results, we can see the possibility of the dynamic simulation program to develop a new Maglev vehicle system.

• 로봇학회논문지
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• 제13권4호
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• pp.256-264
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• 2018

Unlike normal wheels, the Mecanum wheel enables omni-directional movement regardless of the orientation of a mobile robot. In this paper, a robust trajectory tracking control method is developed based on the dynamic model of the Mecanum wheel mobile robot in order that the mobile robot can move along the given path in the environment with disturbance. The method is designed using the impedance control to make the mobile robot to track the path, and the integral sliding mode control for robustness to disturbance. The good performance of the proposed method is verified using the MATLAB /Simulink simulation and also through the experiment on an actual Mecanum wheel mobile robot. In both the simulation and the experimentation, we make the mobile robot move along a reference trajectory while maintaining the robot's orientation at a constant angle to see the characteristics of the Mecanum wheel.

• 융합신호처리학회논문지
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• 제9권4호
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• pp.272-279
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• 2008

장면 전환 검출은 비디오 데이터의 효율적인 관리를 위한 주요 기술로서 다양한 영상에 실제적으로 적용하기 위해서 적응적인 검출 기술이 요구된다. 본 논문에서는 가변 참조 구간의 평균 특징값을 이용한 적응적인 장면 전환 검출 알고리즘을 제안한다. 제안하는 알고리즘은 비디오 프레임에서 추출한 특징값들 중에서 가변 구간 동안의 평균 특징값을 참조하여 적응적 임계값을 정의하고, 특징값과 임계값을 비교하여 장면 전환 유무를 판단한다. 동일한 비디오 데이터를 사용한 실험을 통해서 제안한 방법이 기존의 방법들보다 검출 결과가 최대 15%이상 향상되었음을 확인하였다. 제안한 방법은 여러 가지 특징 추출 방법에 대해서도 좋은 성능을 나타내었으며, 홈캐스트사의 TVUS 모델에서 구현함으로써 하드웨어 성능이 낮은 플랫폼에서 실시간 장면 전환 검출이 가능한 것을 확인하였다. 따라서 제안하는 방법은 휴대용 미디어 장치나 유사 휴대형기기에서 유용하게 사용될 수 있을 것이다.

• 방송공학회논문지
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• 제17권4호
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• pp.676-683
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• 2012

동영상 부호화에서 움직임 추정은 구현 복잡도에 가장 크게 영향을 미친다. 본 논문에서는 깊이 카메라와 색상 카메라를 동시에 이용하여 움직임 추정의 복잡도를 줄이는 방법을 제안한다. 깊이 카메라로부터 얻어진 거리 정보로 동영상내 객체 정보를 얻고, 비슷한 거리에 있는 화소들을 그룹화하여 동일한 객체로 라벨링을 수행한다. 라벨링된 현재 및 참조 화면내에서 움직임 추정 블록을 세부분(배경, 객체내부, 경계)의 탐색영역으로 구분하여 적응적으로 판단한다. 현재 블록이 객체내부영역이면 참조 화면에서 객체내부영역에만 움직임 추정을 탐색하고, 배경영역이면 블록은 참조 화면에서 배경영역에만 탐색한다. 모의실험을 바탕으로 전역탐색방법에 비하여 제안된 방법은 움직임 추정 차신호가 동일하게 유지되면서 탐색 복잡도가 크게 줄어듬을 확인할 수 있다.

• The Journal of Asian Finance, Economics and Business
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• 제6권3호
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• pp.19-26
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• 2019

The paper aims to measure stock price volatility on Ho Chi Minh stock exchange (HSX). We apply symmetric models (GARCH, GARCH-M) and asymmetry (EGARCH and TGARCH) to measure stock price volatility on HSX. We used time series data including the daily closed price of VN-Index during 1/03/2001-1/03/2019 with 4375 observations. The results show that GARCH (1,1) and EGARCH (1,1) models are the most suitable models to measure both symmetry and asymmetry volatility level of VN-Index. The study also provides evidence for the existence of asymmetric effects (leverage) through the parameters of TGARCH model (1,1), showing that positive shocks have a significant effect on the conditional variance (volatility). This result implies that the volatility of stock returns has a big impact on future market movements under the impact of shocks, while asymmetric volatility increase market risk, thus increase the attractiveness of the stock market. The research results are useful reference information to help investors in forecasting the expected profit rate of the HSX, and also the risks along with market fluctuations in order to take appropriate adjust to the portfolios. From this study's results, we can see risk prediction models such as GARCH can be better used in risk forecasting especially.

• 한국비블리아학회지
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• 제9권1호
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• pp.221-240
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• 1998

국내에서 제작되는 데이터베이스의 품질 개선에 도움을 주고자 교육학 분야에서 널리 알려진 ERIC 데이터베이스에 대한 품질의 평가작업을 수행하였다. 선정된 데이터베이스는 웹상에서 검색이 가능한 ASKERIC 이었으며, 데이터의 정확성, 일관성, 완전성, 현행성의 4가지 평가기준을 가지고 평가가 진행되었다. 정확성의 측정은 미국과 영국식 단어의 차이를 가진 글자를 가지고 수행되었는데 미국식 영어로 색인된 문헌의 검색결과가 영국식 영어로 된 문헌의 검색결과보다 훨씬 많은 것을 발견하였다. 틀리기 쉬운 10개의 단어를 가지고 철자에러를 체크해 보았을 때 상당한 양의 철자에러가 발견되었다. 일관성의 측정을 위해 색인어의 일관성을 조사하였는데 시소러스가 동의어 통제를 완전히 감당하지 못하는 것으로 드러났고 대소문자의 구별은 이루어지지 않는 것으로 나타났다. 완전성을 검증하기 위해 접근필드를 조사하였는데 ASKERIC은 상당히 다양한 접근 필드를 가지고 있었으나 매뉴얼에 나타난 접근필드와 검색창에 나타난 접근필드는 달랐으며. 검색창에 나타난 추가적인 필드를 가지고 검색하였을 때는 에러가 나타났다. 매뉴얼에서는 데이터의 갱신작업이 매월 이루어진다고 명시하였지만 현행성을 위해 실제로 검색해 보았을 때 데이터의 갱신주기는 매우 느린 것으로 나타났다. 그럼에도 불구하고 일반적으로 ERIC 데이터베이스의 품질은 대체로 양호한 것으로 나타났는데 이는 시스템의 자동 에러수정을 위한 부단한 노력과 이용자 피드백을 시스템의 품질 향상에 적극 반영하는 정책덕분인 것으로 보인다.

• 제어로봇시스템학회논문지
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• 제21권1호
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• pp.1-6
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• 2015

This paper investigates the longitudinal flight dynamics and stability of flapping-wing micro air vehicles. Periodic external forces and moments due to the flapping motion characterize the dynamics of this system as NLTP (Non Linear Time Periodic). However, the averaging theorem can be applied to an NLTP system to obtain an NLTI (Non Linear Time Invariant) system which allows us to use a standard eigen value analysis to assess the stability of the system with linearization around a reference point. In this paper, we investigate the dynamics and stability of a hawkmoth-scale flapping-wing air vehicle by establishing an LTI (Linear Time Invariant) system model around a hovering condition. Also, a direct time integration of full nonlinear equations of motion of the flapping-wing micro air vehicle is conducted to see how the longitudinal flight dynamics appear in the time domain beyond the reference point, i.e. hovering condition. In the study, the flapping-wing air vehicle exhibited three distinct dynamic modes of motion in the longitudinal plane of motion: two stable subsidence modes and one unstable oscillatory mode. The unstable oscillatory mode is found to be a combination of a pitching velocity state and a forward/backward velocity state.

• 핵의학기술
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• 제17권2호
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• pp.101-106
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• 2013

Purpose: As UBC IRMA is being tested, patients out of the reference value are reacting within the value again a few days later the urine collection tested, which causes the reliability of the test to decrease as a result. In this study, we can assume that the physiological changes in the factors would affect the results. The purpose of the study is to find out whether hematuria and proteinuria in the sample as well as the interval time (3 hours or more recommended) have affected the results. As a result, we could discover the changes in factors and increase the reliability of the test. Materials and Methods: 468 people (female: 249, male: 219) who came for the check-up were presented herein for medical examination from 2013.3.15 to 2013.1.2. Some people out of 468 who have reacted onto the reference value were divided into group low titer zone, ow-middle titer zone, and middle-high titer zone and tested for hematuria and proteinuria. During that period, 48 outpatients were asked to fill in a questionnaire regarding the urination interval time. The reagents used were (IDL Biotech AB, Sweden) and UBC IRMA. Results: Of the patients that are formed in the reference value of ($0.1-34.0{\mu}g/L$) turn out to be 52.7 years average age in their low concentration, ($mean{\pm}SD$) of the value of $0.10{\pm}0.02{\mu}g/L$. Among 80 people (50.8%, female: 49.2%), 16 patients (20%) have shown reaction to microscopic hematuria and 10 patients (12.5%) responded to proteinuria. In the average low concentration under 52.5 years of average age, 43 people (53%) have shown reaction to microscopic hematuria and 21 people (26.3%) are proteinuric patients out of 80 patients (male: 50.8%, female: 51.3%). In the middle high concentration of $11.8{\pm}4.82{\mu}g/L$ under the average age 51.7 years, 35 patients (53%) have responded to the microscopic hematuria and proteinuric patients are 26 people (39.3%) out of 66 people (men: 44%, women: 56%). In addition, in the concentration of $51.7{\pm}43.5{\mu}g/L$, some patients who get out of the reference value are observed as the average age of 52.0. 11 patients (78.6%) out of 14 (male: 35.7%, female: 64.3%) react to the microscopic hematuria. There show 6 people (42.8%) who turn out to be as proteinuric patients. As for the interval time, $1.67{\pm}3.71{\mu}g/L$ was the average value among 48 patients (female: 45.8%, male: 54.2%). Conclusion: We cannot see if proteinuria and hematuria directly affect abnormal results of inspection of 8,18 cytokeratin; however, we can find out that they statistically have an influence on highly generating UBC among several mechanisms. Also, although urination interval time was various every 15 minutes, we it does not affect these results.

• 한국의사학회지
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• 제15권2호
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• pp.117-134
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• 2002

"Gup Yu Bang" is the first Korean book that specialized in pediatrics. It was written by Jo Jeong-jun on the 25th year of King Young Jo in the Choson dynasty. He quoted a lot of information from "Yi-Hak-Yip-Mun" by Yi-cheon in the Myung dynasty and "Xiao Er Yao Zheag Zhi Jue" by Qian Yi in the Song dynasty, but he added his own opinions and clinical experiences to the book. In addition to that, the book explains not only symptoms and prescriptions but also the etiology and pathology of children's diseases. In particular, he showed a great deal of creativity in his book called "Dong Bang Six Fu's Qi Principle" After studying "Gup Yu Bang", I have drawn the following conclusions. 1. Prevention is more important than treatment in pediatrics. 2. When we make a diagnosis, facial inspection has priority. 3. In terms of treatmemt, Wu zang is a general rule. Therefore, we should focus on Wu zang and Pi Wei. 4. The following terms definition symptom cause prescription clinical example prevention are to be explained with reference to the nature or symptoms of the disease. 5. We can see that smallpox was more widspread than the measles in the period of King Young Jo. 6. Even though he was influenced by "Yi-Hak-Yip-Mun", "Xiao Er Yao Zheag Zhi Jue", and "Dong eui bo gam", his own explanation is clearer in his book called "Gup Yu Bang" which is based on his own clinical experiences. 7. "Gup Yu Bang" is a practical and experiential book.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 춘계학술대회 논문집 센서 박막재료 반도체재료 기술교육
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• pp.86-89
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• 2002

We give pressure stimulation into organic thin films and then manufacture a device under the accumulation condition that the state surface pressure is 10[mN/m]. In processing of a device manufacture, we can see the process is good from the change of a surface pressure for organic thin films and transfer ratio of area per molecule. The structure of manufactured device is Au/Poly-${\gamma}$ Benzyl $_D$-Glutamate/Al and Au/Poly-${\gamma}$ Benzyl $_D$-Glutamate/Au; the number of accumulated layers is 1, 3, 5 and 7. Also, we then examined of the MIM device by means of I-V. The I-V characteristic of the device is measured from 0 to +2[V]. We determined electrochemical measurement by using cyclic voltammetry with a three-electrode system. LB film accumulated by monolayer on an ITO. In the cyclicvoltammetry, An Ag/AgCl reference electrode, a platinum wire counter electrode and LB film-coated ITO working electrode measured in $LiBF_4$ solution, stable up to 0.9V vs. Ag/AgCl.