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      • KCI등재

        시간지연 시스템의 응답특성 개선을 위한 제어기 설계

        이석원,양승현,Lee, Suk-Won,Yang, Seung-Hyun 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.7

        시간지연이 존재하는 시스템의 제어기 설계에 많이 사용되는 Smith Predictor는 플랜트와 모델이 완전히 일치해야만 특성방정식에서 시간지연을 제거 할 수 있기 때문에 실제 공정에서는 적용하기가 매우 어렵다. 본 논문에서는 Smith Predictor의 모델을 플랜트와 일치한 식이 아닌 시간지연을 포함한 2차식 형태로 제안하여 큰 시간지연에서의 응답특성을 향상 시켰다. PI 제어기의 적분상수의 범위를 제안하였다. The practical control problems for the lime-delay system is considered. The delay-free characteristics of the Smith Predictor is available only when both the process and it's model are exactly matched. So it does not used widely in practical industrial processes. In this paper, using the 2nd-order plus dead time model in place of the plant model of the Smith Predictor, the proposed controller shows the improved performance in case of the very long time delay. And the range of integral constant of the PI controller is also proposed.

      • SCOPUSKCI등재

        IVF-ET Program에서 Blastocyst 배아의 발생에 관한 연구 - II. 난구세포 공동배양에 의한 Blastocyst 배아의 발생

        이석원,윤산현,윤혜균,조현진,허용수,윤혜진,박세필,이원돈,임진호,Lee, Suk-Won,Yoon, San-Hyun,Yoon, Hye-Gyun,Cho, Hyon-Jin,Heo, Yong-Soo,Yoon, Hye-Jin,Park, Se-Pill,Lee, Won-Don,Lim, Jin-Ho 대한생식의학회 1998 Clinical and Experimental Reproductive Medicine Vol.25 No.1

        This study was carried out to investigate the development rates of human embryos co-cultured with cumulus cells to each blastocyst stage. Human zygotes were co-cultured on cumulus cell monolayer in YS medium supplemented with 20% hFF. On day 2, if patient had four or more "good" embryos (regular blastomeres without fragmentation), embryos were further cultured for 72hrs. Blastocysts on day 5 were classified into early blastocyst (ErB), early expanding blastocyst (EEB), middle expanding Blastocyst (MEB), and expanded blastocyst (EdB) on the basis of their morphological aspects of trophectoderm cells and blastocoele. Subsequently, maximum 3 of best blastocysts were transferred in 486 cycles. The results in this study were as follows: Patients who had four or more "good" embryos on day 2 were 498 persons, but patients whose embryos could not be transferred due to failure in development to the blastocyst stage on day 5 were 12 persons (2.4%). The development rate of embryos to the blastocyst stage was 58.2% (2,885/4,957) on day 5, and the rates that developed to the ErB, EEB, MEB, and EdB stage were 15.0% (743/4,957), 14.9% (739/4,957), 14.4% (714/ 4,957), and 13.9% (689/4,957), respectively. Total 1366 blastocysts were transferred in 486 cycles (mean number=2.81). The implantation rate and the ongoing implantation rate obtained by observing the number of G-sac and FHB were 29.9% (409/1,366) and 22.5% (308/1,366), respectively. The clinical pregnancy rate was 51.2% (249/486), and the ongoing pregnancy rate' was 39.1% (190/486). Among women showing ongoing pregnancy, women with singleton were 50% (95/190), women with twin were 37.9% (72/190), and women with triplet were 12.1% (23/190). Although triplet pregnancy rate in this study was high such as 12.1%, because many blastocysts with high viability were produced in our co-culture system using cumulus cells on day 5, we really believe that a multiple pregnancy except twin should not occur by selecting good embryos for maximum two blastocyst transfer. These results demonstrate that autologous cumulus cells may be used for the production of blastocysts with high developmental competence, and the use of autologous cumulus cells to be collected easily, and to be treated conveniently at OPU must be an effective means for obtaining high implantation and pregnancy rate.

      • KCI등재후보

        머신비전 기반 ACF 본딩 기법 개발

        이석원,Lee, Seokwon 국제문화기술진흥원 2018 The Journal of the Convergence on Culture Technolo Vol.4 No.3

        Anisotropic conductive film(ACF) bonding is widely used for making fine interconnections between two different materials where soldering is not easily applicable. There are three constraints for the successful implementation of ACF bonding. A bonding contact should be pressed by a hot head with the right pressure and temperature for a pre-defined curing time. In this paper, a method for ACF bonding based on machine vision system is proposed and verified through some experiments. The system calculates the position and orientation of printed circuit boards(PCBs) on a bonding table and estimates the optimal hitting point where the hot head should be applied. Experimental results show that the proposed system achieves better adhesive strength by providing head flatness over contact surfaces. 이방성 도전필름(ACF)을 사용한 본딩은 납땜이 용이하지 않은 이질적인 소재 간 미세 접합을 형성하는데 널리 사용되어진다. 성공적인 ACF 본딩 구현을 위한 3가지 제한조건이 존재한다. 본딩 접촉점은 설정된 작업 시간동안 적절한 압력과 온도를 유지한 헤드에 의해서 압착되어야 한다. 본 논문에서는 머신 비전을 기반으로 한 ACF 본딩기법을 제안하고 실험을 통해 검증한다. 시스템은 본딩 작업대 상의 PCB 위치 및 방향을 계산하고 헤드가 압착되어야 하는 최적의 접촉점을 결정한다. 제안한 시스템이 접촉면 상의 헤드 평탄도를 보장함으로써 접착력을 향상시킬 수 있음을 실험결과를 통해 보여준다.

      • KCI등재

        임베디드 웹 서버를 이용한 자동차용 모니터링 및 제어기 개발에 관한 연구

        이석원,양승현,Lee, Suk-Won,Yang, Seung-Hyun 한국조명전기설비학회 2005 조명·전기설비학회논문지 Vol.19 No.2

        In this paper, Web server is built up using PXA255, 32bit RISC processor with porting Embedded Linux and GoAhead HTTP(Hyper Text Transfer Protocol) web server, and the system which can monitor and control the environment and condition for AICC(Automatic Intelligent Cruise Control) is realized For sensing the operation condition and change of vehicle the desired data is derived by interfacing ECU(Electric Control Unit) and Embedded system and the rpm of engine is controlled by step motor connected to throttle valve. 본 연구에서는 임베디드 리눅스와 HTTP(Hypertext Transfer Protocol) 웹 서버인 GoAhead를 포팅한 32비트 RISC프로세서인 PXA255를 이용하여 웹 서버를 구축하고, 웹 서버를 기반으로 자동차의 순항제어나 무인 운전을 위한 일련의 환경과 상황을 모니터링하고 제어할 수 있는 시스템을 구현하였다. 자동차의 동작 상태와 변화를 감지하기 위해서 ECU와 임베디드 시스템을 인터페이스 시켜 필요한 데이터를 추출하고, 스로를 밸브에 스텝모터를 연결하여 자동차의 엔진을 회전시켜 자동차의 무인 이동을 제어한다.

      • KCI등재

        총의치 환자 만족도의 영향요인

        이석원,정문규,Lee Suk-Won,Chung Moon-Kyu 대한치과보철학회 2005 대한치과보철학회지 Vol.43 No.5

        Statement of problem: In spite of the progress in techniques and materials in complete denture prosthodontics, patients still complain of discomfort after the insertion of complete dentures. For the last several decades many prosthodontists tried to find factors influencing patient complete denture satisfaction, however the reported results became a controversy. Purpose: The purpose of the present study was to verify the factors influencing patient satisfaction with complete dentures using multiple regression analysis. Materials and methods: 33 patients who visited the department of prosthodontics, dental hospital of Yonsei University, 4 to 6 weeks after the complete denture delivery, were asked to complete the questionnaires on complete denture satisfaction, social variables and psychological variables. The Prosthodontists who treated the patients with complete dentures were also asked to complete the questionnaires on evaluation of patients' oral condition and technical quality of dentures. The factors influencing patients' satisfaction with their complete dentures were analyzed using multiple regression analysis. Results: Among the patients' sociodemographic variables. the variables of relationship with children, economic status, housing condition, other people's opinions of dentures and gender were the influential factors on patients' satisfaction with complete dentures. Patients showing the symptoms of depression, one of the psychological variables, were dissatisfied with their complete dentures. In spite of the good oral condition, patients were dissatisfied with complete dentures, where-as the technical quality of dentures did not influence patients' complete denture satisfaction. Conclusion : According to the results above, patients' sociodemographic and psychological variables rather than clinical variables including oral condition and technical quality of dentures were the influential factors on complete denture satisfaction. The results of this study may not only enable prosthodontists to predict the success and failure of complete denture treatment, but also help both prosthodontists and patients be informed of the essentials of increasing satisfaction with complete dentures.

      • KCI등재

        국산 꽃차에 대한 미국과 일본의 소비자인식 및 지불의사에 대한 연구

        이석원,양성범,Lee, Seog-Won,Yang, Sung-Bum 한국식품영양학회 2014 韓國食品營養學會誌 Vol.27 No.3

        The objective of this study is to propose an export strategy due to an analysis of USA and Japan consumer's perception and willingness-to-pay for flower tea. For that, we conducted a survey on the consumer's perception on flower tea compared with leaf tea such as green tea. We also analyzed the willingness to purchase and pay for it. The reasons of drinking of flower tea for USA consumer are 'flavor'-followed by 'taste', and for Japanese consumer 'relaxation'-followed by 'flavor' in order. Both of them consider 'quality', 'safety'- and 'origin' in order when they purchase flower tea. USA consumers have a willingness-to-pay of about 8.3% and Japanese consumers have a willingness-to-pay of about 29.1%. Based on those results, it is necessary to differentiate the process and marketing strategies for the export of flower tea.

      • 수치해석 기법을 이용한 복개 터널구조물의 거동에 관한 연구

        이석원,이규필,배규진,Lee, Seok-Won,Lee, Gyu-Phil,Bae, Gyu-Jin 한국터널지하공간학회 2003 터널기술 Vol.5 No.1

        In the deign of cut and cover tunnel, the structural analysis such as rigid frame analysis has been used for its simplicity and convenience. The structural analysis, however, can not consider the geological and geotechnical factors such as soil arching effect. In this study, the dominant factors influencing the behavior of cut and cover tunnel such as interface element, slope of excavation plane, distance between slope and tunnel lining, and location of slope of covered soil, were investigated by the numerical analysis to develop the analysis technique and design technology. Based on the results, the variation of bending moment, shear stress, axial force and displacements were evaluated and analyzed for each factor. 현재 복개 터널구조물의 해석 및 설계에는 구조공학적 모델링 기법이 널리 적용되고 있으나, 이러한 구조공학적 모델링 기법은 지형적인 영향인자 및 soil arching 등과 같은 지반공학적 측면의 영향인자를 고려하기에 많은 어려움이 있다. 따라서, 본 연구에서는 복개 터널구조물의 합리적이고 경제적인 설계를 위하여 복개 터널구조물의 거동에 영향을 미치는 인자로써 콘크리트 라이닝과 성토체의 계면요소, 굴착사면의 경사, 이격거리 및 성토사면 등을 고려하여 지반공학적 모델링 기법을 이용한 수치해석 수행하였다. 이의 결과를 토대로 각 영향인자 변화에 따른 복개 터널구조물의 역학적 거동특성을 분석하였다.

      • KCI등재

        임플랜트 주위 연조직세포의 세포-기질 접착

        이석원,류인철,한종현,이재봉,Lee Suk-Won,Rhyu In-Chul,Han Chong-Hyun,Lee Jai-Bong 대한치과보철학회 2006 대한치과보철학회지 Vol.44 No.1

        The importance of soft tissue response to implant abutments has become one of the major issues in current implant dentistry. To date, numerous studies have emphasized on maintaining connective tissue barriers in quantity, as well as in quality fir the long term success of dental implants. The cells mainly consisting the soft tissue around dental implants are fibroblasts and epithelial cells. The mechanism of the fibroblasts adhesions to certain substrata can be explained by the 'focal adhesion' theory. On the other hand, epithelial cells adhere tn the substratum via hemidesmosomes. The typical integrin-mediated adhesions of cells to certain matrix are called 'cell-matrix adhsions'. The focal adhesion complex of fibroblasts, in relation to the cell-matrix adhsions, consists of the extracellular matrix(ECM) such as fibronectin, the transmembrane proteins such as integrins, the intracellular cytoplasmic proteins such as vinculin, talin, and more, and the cytoskeletal structures such as filamentous actin and microtubules. The mechanosensory function of integrins and focal adhesion complexes are considered to play a major role in the cells adhesion, migration, proliferation, differentiation, division, and even apoptosis. The '3-D matrix adhesions' defined by Cukierman et al. makes a promising future for the verification of the actual process of the cell-matrix adhesions in vivo and can be applied to the field of implant dentistry in relation to obtaining strong soft tissue attachment to the implant abutments.

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