• Title/Summary/Keyword: Kiyoung

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Study on MPPT controller using limit cycle (리미트 사이클을 이용한 MPPT 제어기에 대한 연구)

  • Kang Taekyung;Koh Kanghoon;Kwon Soonkurl;Suh Kiyoung;Nakaoka Mutsuo;Lee Hyunwoo
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.160-163
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    • 2005
  • This paper proposes a simple MPPT control scheme of a Current-Control-Loop Error system Based that can be obtains a lot of advantage to compare with another digital control method, P&O and IncCond algorithm, that is applied mostly a PV system. An existent method is needed an expensive processor such as DSP that calculated to change the measure power of a using current and voltage sensor at the once. Therefore, it is applied a small home power generation system that required many expenses. But, a proposed method is easy to solve the cost reduction and power unbalance problems that it is used by control scheme to limit error of a current control of common sensor. This proposed algorithm had verified through a simulation and an experiment on battery charger using PIC that is the microprocessor of a low price.

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Blood flow velocity measurement device using a pulse wave and ECG (맥파와 심전도를 이용한 혈류속도 측정장치)

  • Jeong, Jinhyung;Heo, Sun oh;Kim, Taegeun;Kim, Yunjeong;Lee, Kiyoung
    • The Journal of Korea Institute of Information, Electronics, and Communication Technology
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    • v.6 no.1
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    • pp.57-64
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    • 2013
  • 본 논문에서는 심전도(ECG)와 SPO2를 이용하여 혈류속도를 측정하였다. 심전도(ECG)와 손가락 검지손가락 끝의 SPO2농도로 얻는 맥파를 동시에 측정하여 두 파형의 피크값의 시간차를 분석하여 혈류속도를 계산하는 방법을 연구하였다. 심전도(ECG)와 SPO2를 동시 측정 분석하는 시스템으로서 정상인 10명과 임상참가자 3명에 대한 심전도(ECG)와 손가락 검지 손가락 끝의 SPO2농도로 얻는 맥파를 동시에 측정하여 비교 분석한 결과 자료에서 보는 것과 같이, 심혈관계 환자들이 일반적으로 혈류 속도가 빠르다는 것일 볼 수 있다. 또한 정상인들 중에서도 남자와 여자의 속도차이가 있음을 알 수 있다.

English Tutoring System Using Chatbot and Dialog System (챗봇과 대화시스템을 이용한 영어 교육 시스템)

  • Choi, Sung-Kwon;Kwon, Oh-Woog;Lee, Kiyoung;Roh, Yoon-Hyung;Huang, Jin-Xia;Kim, Young-Gil
    • Proceedings of the Korea Information Processing Society Conference
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    • 2017.04a
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    • pp.958-959
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    • 2017
  • 본 논문은 챗봇과 대화시스템을 이용한 영어 교육 시스템을 기술하는 것을 목표로 한다. 본 논문의 시스템은 학습자의 대화 흐름을 제한하지 않고 주제를 벗어난 자유대화를 허용하며 문법오류에 대한 피드백을 한다. 챗봇과 대화시스템을 이용한 영어 교육 시스템은 대화턴 성공률로 평가되었는데, 평균 대화턴 성공률은 80.86%였으며, 주제별로는 1) 뉴욕시티투어 티켓 구매 71.86%, 2) 음식주문 71.06%, 3) 건강습관 대화 85.41%, 4) 미래화폐에 대한 생각 조사 95.09%였다. 또한 영어 문법 오류 교정도 측정되었는데 문법 오류 정확률은 66.7%, 재현율은 31.9%였다.

Quasi-Periodic Oscillation of a Magnetic Cataclysmic Variable, DO Draconis

  • Han, Kiyoung;Kim, Yonggi;Andronov, Ivan L.;Yoon, Joh-Na;Chinarova, Lidia L.
    • Journal of Astronomy and Space Sciences
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    • v.34 no.1
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    • pp.37-44
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    • 2017
  • In this paper, analysis results of the photometric data of DO Dra will be presented. DO Dra had been observed with 1 m LOAO telescope and 0.6 m CBNUO telescope from 2005 through 2014. The data shows kind of periodic oscillation behavior in the orbital period and also in the spin period. It has been found that these QPOs are not observed always and that the periods vary from 30 min to 80 min. We also found that the period variation seems to repeat itself with the period of 13.5 days. It is essential to monitor this object in the future as well as to carry out model calculation in order to have better understanding of these QPO phenomena.

The Effect of Internet Use on the Changes in Family Systems

  • Lee Hyunah;Lee Kiyoung
    • International Journal of Human Ecology
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    • v.5 no.2
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    • pp.61-80
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    • 2004
  • The introduction of the Internet in homes had an effect on family systems. The purpose of this study is to investigate the changes in family systems due to Internet use in South Korea. This study classified the types of changes in the family systems and analyzes the characteristics of each type. Systems approach provides the theoretical framework for this study. First, the cluster analysis demonstrated the three types of the changes in the family subsystems due to housewives' Internet use: 'positive changes', 'negative changes', and 'no changes'. Second, there are different characteristics among the types of changes according to demographic, Internet-related, and intra-system dynamic factors. These results suggest several implications for public policy. To utilize the Internet as a useful tool to improve the quality of family life, housewives must have the ability to control the Internet use and to manage their resources. In order to enhance their abilities of using the Internet, it may be necessary for the government to provide public educational programs for housewives.

A Basic Study on Influential Factors of Building Damages According to Hurricane by Using Correlation Analysis (상관분석을 통한 태풍에 따른 건축물 피해액의 영향인자 도출)

  • Kim, Boo-Young;Yang, Seongpil;Kim, Sangho;Son, Kiyoung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.164-165
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    • 2014
  • In the case of U.S, various damage prediction models of buildings from natural disasters have been used widely in many organizations such as insurance companies and governments. In South Korea, although studies regarding damage prediction model of hurricane have been conducted, the scope has been only limited to consider the property of hurricane. However, it is necessary to consider various factors such as socio-economic, physical, geographical, and built environmental factors to predict the damages. Therefore, as a basic study on a damage prediction model development of buildings, this study is to analyze the correlation between various factors related to hurricane. The findings of study can be utilized to develop for predicting the damage of hurricane on buildings.

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A Basic Study on an Application of the Modified Epoxy Mortar for Seismic Reinforcement (내진보강을 위한 변성에폭시 모르터 활용방안 기초연구)

  • Kim, Boo-Young;Yang, Seongpil;Kim, Sangho;Son, Kiyoung
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2014.05a
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    • pp.176-177
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    • 2014
  • Although the modified epoxy mortar can be applied to the reinforcement for RC member, the mortar has been little used in construction site. In addition, there is a few studies regarding the experiment as the material improving the seismic performance. Therefore, this study is to propose an effective reinforcement alternative for RC Ordinary Moment Resisting Frame (OMRF) through evaluation of seismic performance and economic analysis. The findings of this study can be utilized as the basic data in construction sites when the modified epoxy mortar is applied for seismic performance reinforcement.

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Enhancing Depth Accuracy on the Region of Interest in a Scene for Depth Image Based Rendering

  • Cho, Yongjoo;Seo, Kiyoung;Park, Kyoung Shin
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.8 no.7
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    • pp.2434-2448
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    • 2014
  • This research proposed the domain division depth map quantization for multiview intermediate image generation using Depth Image-Based Rendering (DIBR). This technique used per-pixel depth quantization according to the percentage of depth bits assigned in domains of depth range. A comparative experiment was conducted to investigate the potential benefits of the proposed method against the linear depth quantization on DIBR multiview intermediate image generation. The experiment evaluated three quantization methods with computer-generated 3D scenes, which consisted of various scene complexities and backgrounds, under varying the depth resolution. The results showed that the proposed domain division depth quantization method outperformed the linear method on the 7- bit or lower depth map, especially in the scene with the large object.

Charges of TIP4P water model for mixed quantum/classical calculations of OH stretching frequency in liquid water

  • Jeon, Kiyoung;Yang, Mino
    • Rapid Communication in Photoscience
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    • v.5 no.1
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    • pp.8-10
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    • 2016
  • The potential curves of OH bonds of liquid water are inhomogeneous because of a variety of interactions with other molecules and this leads to a wide distribution of vibrational frequency which hampers our understanding of the structure and dynamics of water molecules. Mixed quantum/classical (QM/CM) calculation methods are powerful theoretical techniques to help us analyze experimental data of various vibrational spectroscopies to study such inhomogeneous systems. In a type of those approaches, the interaction energy between OH bonds and other molecules is approximately represented by the interaction between the charges located at the appropriate interaction sites of water molecules. For this purpose, we re-calculated the values of charges by comparing the approximate interaction energies with quantum chemical interaction energies. We determined a set of charges at the TIP4P charge sites which better represents the quantum mechanical potential curve of OH bonds of liquid water.

Application of Artificial Neural Networks for Prediction of the Strength Properties of CSG Materials

  • Lim, Jeongyeul;Kim, Kiyoung;Moon, Hongduk;Jin, Guangri
    • Journal of the Korean GEO-environmental Society
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    • v.19 no.5
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    • pp.13-22
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    • 2018
  • The number of researches on the mechanical properties of cemented sand and gravel (CSG) materials and the application of the CSG Dam has been increased. In order to explain the technical scheme of strength prediction model about the artificial neural network, we obtained the sample data by orthogonal test using the PVA (Polyvinyl alcohol) fiber, different amount of cementing materials and age, and established the efficient evaluation and prediction system. Combined with the analysis about the importance of influence factors, the prediction accuracy was above 95%. This provides the scientific theory for the further application of CSG, and will also be the foundation to apply the artificial neural network theory further in water conservancy project for the future.