• Title/Summary/Keyword: Choi Chi-won

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Estimating Paddy Rice Evapotranspiration of 10-Year Return Period Drought Using Frequency Analysis (빈도 분석법을 이용한 논벼의 한발 기준 10년 빈도 작물 증발산량 산정)

  • Yoo, Seung-Hwan;Choi, Jin-Yong;Jang, Min-Won
    • Journal of The Korean Society of Agricultural Engineers
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    • v.49 no.3
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    • pp.11-20
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    • 2007
  • Estimation of crop consumptive use is a key term of agricultural water resource systems design and operation. The 10-year return period drought has special aspects as a reference period in design process of irrigation systems in terms of agricultural water demand analysis so that crop evapotranspiration (ETc) about the return period also has to be analyzed to assist understanding of crop water requirement of paddy rice. In this study, The ETc of 10-year return period drought was computed using frequency analysis by 54 meteorological stations. To find an optimal probability distribution, 8 types of probability distribution function were tested by three the goodness of fit tests including ${\chi}^2$(Chi-Square), K-S (Kolmogorov-Smirnov) and PPCC (Probability Plot Correlation Coefficient). Optimal probability distribution function was selected the 2-parameter Log-Normal (LN2) distribution function among 8 distribution functions. Using the two selected distribution functions, the ETc of 10-year return period drought was estimated for 54 meteorological stations and compared with prior study results suggested by other researchers.

Extracting Building Boundary from Aerial LiDAR Points Data Using Extended χ Algorithm (항공 라이다 데이터로부터 확장 카이 알고리즘을 이용한 건물경계선 추출)

  • Cho, Hong-Beom;Lee, Kwang-Il;Choi, Hyun-Seok;Cho, Woo-Sug;Cho, Young-Won
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.31 no.2
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    • pp.111-119
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    • 2013
  • It is essential and fundamental to extract boundary information of target object via massive three-dimensional point data acquired from laser scanner. Especially extracting boundary information of manmade features such as buildings is quite important because building is one of the major components consisting complex contemporary urban area, and has artificially defined shape. In this research, extended ${\chi}$-algorithm using geometry information of point data was proposed to extract boundary information of building from three-dimensional point data consisting building. The proposed algorithm begins with composing Delaunay triangulation process for given points and removes edges satisfying specific conditions process. Additionally, to make whole boundary extraction process efficient, we used Sweep-hull algorithm for constructing Delaunay triangulation. To verify the performance of the proposed extended ${\chi}$-algorithm, we compared the proposed algorithm with Encasing Polygon Generating Algorithm and ${\alpha}$-Shape Algorithm, which had been researched in the area of feature extraction. Further, the extracted boundary information from the proposed algorithm was analysed against manually digitized building boundary in order to test accuracy of the result of extracting boundary. The experimental results showed that extended ${\chi}$-algorithm proposed in this research proved to improve the speed of extracting boundary information compared to the existing algorithm with a higher accuracy for detecting boundary information.

A Landscape Design of Eunpyeong New Town District 2, Seoul (서울 은평 뉴타운 2지구 조경설계)

  • Ahn Gye-Dong;Choi Jung-Min
    • Journal of the Korean Institute of Landscape Architecture
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    • v.33 no.4 s.111
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    • pp.143-154
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    • 2005
  • The Seoul Housing Corporation pronounced a design competition for Eunpyeng New Town District 2 in March of 2005. The authors collaborated on this design and won rot prize. Design guidelines of this competition were to make environmentally sustainable design, to develop as a resort site and cultural place for everyday life of residents, to link with green fabric of the district, and to elevate positive image and identity of Eunpyeng New Town district by creating a attractive landscape. The authors developed design concept and strategy within the guidelines and site conditions. The environmental setting of this site was characterized by mountain to the rear of the site with a stream passing through the district and the front of the site. This is the most important condition for the location principle of residence in Fung Shui theory. Therefore, the schema of the design was introduced by Fung Shui and Chi of place. To evolve design concept, we reinterpret the Fung Shui and Chi in the site combining with modem landscape design strategy, so that good place making could bring about well-being life of residents. By doing that, design concept of the proposal evolved as follows: 'fullness of comfortable life', 'adaptation of nature', 'inspiration of natural force'. This design approach is critical reevaluation of regional characters employing modem strategy. It is a conscious strategy of critical regionalism as distinguished from the traditional site oriented approach. The following are some of the major features in the design: green network and water recycle system in the site, promenade of forest with the experience nature, link to community core, theme gardens with plants having strong fragrances, terrace gardens with different level of housing type, playgrounds and resting places with many types, human scale facilities for residents.

A Comparison of Controlled and Uncontrolled Hypertension Groups Regarding Pulse Shape and Quality of Life (고혈압 환자에서 혈압 조절 여부에 따른 신상(脤象) 및 삶의 질 비교)

  • Choi, In-Young;Han, Chang-Ho;Choi, Dong-Jun;Jung, Seung-Hyun;Shin, Gil-Jo;Lee, Won-Chul
    • The Journal of Internal Korean Medicine
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    • v.30 no.4
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    • pp.880-892
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    • 2009
  • Objectives : This study is about a comparison of controlled and uncontrolled hypertension groups regarding pulse shape and quality of life. We aimed to find out if pulse shape would be able to help with hypertension treatment and care. Methods : We surveyed "controlled and uncontrolled hypertension patients" using SF-36, HTN QoL (measurement scale for the quality of life in hypertensive patients) and 3-D MAC pulse analyzer for pulse shape. Results : The uncontrolled hypertension group tended to have a sink pulse in the left cun. right guan & chi parts compared to the controlled hypertension group. Within the controlled hypertension group, patients who had a float pulse shape in both guan parts had a higher quality of life than patients who had a normal pulse shape. And the patients who had a normal pulse shape in both chi parts had a higher quality of life than patients with a slow or fast pulse shape. Within the uncontrolled hypertension grouP. the patients who had a normal pulse shape in right guan part had a higher quality of life than those with a choppy pulse shape. Nevertheless, these results were limited to only a few quality of life issues and were inconsistent in relation to specific pulse shapes. Conclusion : If we have more samples and better methods for collecting data, we will have better results, allowing us to improve our ability to predict and treat hypertension.

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SVPWM Control using FPGA for In-Wheel Motor Synchronous Control of Electric Vehicle (EV용 인 휠 모터 동기 구동을 위한 FPGA 기반의 SVPWM 제어)

  • Ha, Sung-Pil;Lee, Jung-Hyo;Park, Jin-Ho;Choi, Chi-Hwan;Lee, Teack-Ki;Won, Chung-Yuen
    • Proceedings of the KIPE Conference
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    • 2011.07a
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    • pp.561-562
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    • 2011
  • 인 휠 모터를 이용하여 구동되는 전기차량은 각 모터의 동기 제어가 요구된다. 기존의 마이크로컨트롤러는 구동시킬 수 있는 모터의 개수가 제한되어 인 휠 모터를 이용하여 구동되는 전기차량과 같은 다축 제어 시스템에 적용하기가 어렵다. 따라서 본 논문에서는 FPGA(Field Programmable Gate Array)를 이용하여 4축 동기 SVPWM 기법을 구현하였으며, 시뮬레이션을 통하여 성능을 확인하였다.

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A Experimental study on combustion and exhaust characteristics by intake composition in SI gasoline engine (SI가솔린 기관에서 흡기조성에 따른 연소 및 배기특성에 관한 실험적 연구)

  • Choi, Il-Dong;Kim, Chi-Won;Yoon, Chang-Sik;Kim, Gi-Bok;Lee, Byung-Ho
    • Journal of the Korean Society of Industry Convergence
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    • v.20 no.1
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    • pp.56-66
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    • 2017
  • In this experimental study, it is designed and used the test engine bed which is installed with the exhaust gas recirculation, and in addition to equipped using by oxygen adder. It has been tested and analyzed the combustion and emission characteristics, cycle variability and engine performance by controlling the oxygen volume fraction, EGR rate, engine speed and equivalence ratio.

Grid-Connected Off-Shore Wind Power System Using 3-Level ANPC VSC (Active Neutral-Point-Clamped Voltage Source Converter) (Active NPC를 적용한 계통연계형 해상 풍력 발전용 전력변환 시스템)

  • Hong, Seok-Jin;Shin, Soo-Cheol;Lee, Hee-Jun;Choi, Chi-Hwan;Won, Chung-Yuen;Kim, Hack-Seong
    • Proceedings of the KIPE Conference
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    • 2012.11a
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    • pp.249-250
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    • 2012
  • 해상 풍력 발전은 가장 유망한 재생 에너지원의 하나이며, 육상 풍력 발전보다 풍력이 강력하고 일정하여 장시간 고출력 발생이 가능하다. 또한 소음, 공간적 한계, 경관훼손 등 기존 육상 풍력 발전의 단점을 보완하고 초대형 단지조성이 가능한 장점이 있다. 초대형 해상풍력단지에는 일반적으로 MW급의 해상풍력발전기가 사용된다. 본 논문에서는 MW급의 해상 풍력발전기에 ANPC(Active Neutral-Point-Clamped) Multi-Level VSC(Voltage Source Converter)를 적용하여 Back-to-Back으로 구성한 시스템을 제안하고 계통연계형 풍력 발전 시스템을 모의한 시뮬레이션을 통하여 제안된 시스템의 성능을 검증한다.

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A study on collision detection of industrial robots using the mechanical inertia observer (관성 관측기를 이용한 산업용 로봇의 충돌감지에 관한 연구)

  • Choi, Chi-Hwan;Shin, Soo-Cheol;Lee, Hee-Jun;Kim, Young-Real;Won, Chung-Yuen
    • Proceedings of the KIPE Conference
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    • 2012.11a
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    • pp.65-66
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    • 2012
  • 최근 많은 산업분야에서 로봇이 사용되고 있으며, 로봇을 산업 공정에 적용시키기 위해서는 인간의 협업이 반드시 필요하다. 또한 사람의 안전은 무엇보다 중요하기 때문에, 사람과 로봇이 충돌시 로봇이 정지되는 기능은 반드시 필요하다. 그러므로, 본 논문에서는 추정된 관성과 속도 변화량에 의해 계산된 기계적 토크와, q축 전류에 의해 계산된 전기적 토크를 비교하여 로봇이 사람이나 물체에 충돌시 이를 감지하고, 속도 지령을 감소 시킴으로써 로봇이 정지 하는 기능을 시뮬레이션과 실험을 통하여 검증 하였다.

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The Effect of a Simulated Disability Exercise Program on Attitude and Stereotyping toward People with Disabilities by Nursing Students (간호대학생의 모의장애체험이 장애인에 대한 태도와 고정관념에 미치는 영향)

  • Choi, Eunyoung;Song, Yeoungsuk
    • Korean Journal of Adult Nursing
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    • v.19 no.4
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    • pp.527-534
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    • 2007
  • Purpose: The purpose of this study was to identify the effect of a simulated disability program on attitude and stereotyping by nursing students toward people with disabilities. Methods: A total of 107 undergraduate nursing students attended and completed pre-and post-questionnaires on attitude and stereotyping. The experimental group participated in a simulation exercise program which was composed of wheel-chair mobility and vision modification in Nam-won Rehabilitation Center. The data were analyzed by the SPSS 12.0 program including frequency, percentage, ${\chi}^2$ test and t-test. Results: There was no significant difference in attitude toward people with disabilities between the two groups (t=-.743, p=.459). But there was a significant difference in stereotyping between the experimental and the control group(t=-4.097, p=.000). Conclusion: As the result of this study, we can conclude that the program was effective to improve stereotyping toward people with disabilities.

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An OpenVG Vector Graphics Accelerator (OpenVG 기반 벡터 그래픽 가속기)

  • Choi, Y.;Hong, E.K.;Lee, G.H.;Shen, Y.L.;Kim, T.G.;Kim, H.G.;Oh, H.C.
    • Proceedings of the IEEK Conference
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    • 2008.06a
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    • pp.761-762
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    • 2008
  • This paper presents a hardware accelerator for accelerating vector graphics applications based on the OpenVG standard. Since our design mainly targets embedded applications, we focus on efficient uses of limited resources, especially the memory bandwidth. The designed accelerator can process the images of $640{\times}240$ pixels with moderate complexity at the rate of 30 frames per second.

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