동적인 채널할당을 이용한 결합형 주문형 비디오 서비스

이석원,박승권,Lee Suk Won,Park Sung-Kwon 한국통신학회 2005 韓國通信學會論文誌 Vol.30 No.1a

주문형 비디오 시스템의 설계에 있어 가장 중요하게 고려되고 있는 것은 사용되는 채널의 수를 일정하게 유지하면서 자입자의 대기시간을 줄이는 방법이다. 이러한 연구의 한 시도로 근래에 실시간 주문형 비디오와 유사주문형 비디오의 장점을 결합하는 결합형 주문형 비디오에 대한 연구가 활발히 이루어지고 있다. 결합형 주문형 비디오에 대한 연구는 결국 어떻게 유니캐스트 채널을 사용하는 사용자들을 그룹화하여 멀티캐스트 채널을 사용하도록 할 것인가에 대한 연구이다. 본 논문에서는 동적인 채널을 이용하여 시청자의 대기시간을 기존의 방식에 비해 효율적으로 줄일 수 있는 결합형 주문형 비디오를 제안하겠다. 모의실험 결과 제안된 방식은 10개의 비디오를 100의 채널을 이용하여 0.5 requests/second의 도착률로 서비스할 경우 Unified Video-on-Demand 비해 $551{\%}$의 성능향상을 보였다. 본 논문은 동적채널 할당을 이용하여 채널을 해제하고 다시 사용하는 과정, 성능 모델, 모의실험을 제시한다. In designing a video-on-demand (VoD) system, the major challenge may be how to reduce the channels concurrently used maintaining the client's waiting time. For this reason, the various architectures which integrate the multicast streams with the unicast streams were suggested in order to improve channel efficiency in recent years. In combining multicast with unicast, the ways to group the unicast channels together are important so that clients can share the multicast transmission channels. This paper proposes a hybrid video-on-demand system which gathers the unicast channels in new ways and shares multicast transmission channels efficiently by using dynamic channel allocation architecture. The numerical results demonstrate that the proposed architecture in some case achieves performance gain of $551{\%}$ compared to existing architecture. This paper presents procedure of channel release and reuse, performance analysis, and simulation results of the dynamic channel allocation architecture.

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.

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.

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.

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.

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.

변혁적 리더십과 안전성과의 관계에서 안전분위기의 조절효과: 군 수송부대 병사를 대상으로

이석원 ( Lee Suk-won ),안관영 ( Ahn Kwan-young ),최응순 ( Choi Eung-soon ) 아시아문화학술원 2017 인문사회 21 Vol.8 No.5

본 논문에서는 상급자의 변혁적 리더십, 안전관련 성과 및 안전분위기간의 관계 확인을 통해, 안전사고의 예방노력을 위한 틀을 제시하고자 한다. 이를 위해 군 수송부대 병사를 대상으로 5점 척도에 의한 설문조사를 실시하여 자료를 확보하였다. 요인분석, 다중회귀분석 및 위계적 다중회귀분석를 적용하여 도출한 결론은, 변혁적 리더십이 안전관련 성과에 상당한 영향을 미치며, 안전분위기가 그 영향관계에서 부분적이나마 조절효과를 갖는다는 것이었다. 향후의 안전관련 성과개선을 위해서는 상급자에 대한 변혁적 리더십 교육과 함께, 구성원들 사이에 안전분위기를 확산시키려는 노력이 바람직할 것이다. In this paper, we propose a framework for prevention efforts of safety accidents by identifying the relationship among senior’s transformational leadership, safety related performance and safety climate. For this purpose, a questionnaire survey was conducted on Likert’s 5 point scale for soldiers in the military transport service. The conclusions drawn from factor analysis, multiple regression analysis and hierarchical multiple regression analysis show that transformational leadership has a significant impact on safety performance and safety climate has a partial but moderating effect on its relationship. In order to improve safety related performance in the future, efforts should be made to spread the safety climate among the members in addition to transformational leadership education for the senior.

베이커리 전문점의 브랜드 신뢰와 충성도에 관한 브랜드 증거의 결정요인

이석원(Lee, Suk-Won),김선희(Kim, Seon-Hee),전현모(Jeon, Hyeon-Mo) 한국외식경영학회 2020 외식경영연구 Vol.23 No.1

본 연구에서는 베이커리 전문점 이용고객이 인지하는 브랜드 증거가 소비자의 브랜드 신뢰와 충성도에 어떤 영향을 미치는지에 대해 실증분석하고 그 결과를 바탕으로 베이커리 전문점 브랜드에 대한 소비자의 인식과 충성도를 상세히 분석하여 마케팅 전략 방안을 제시하고자 한다. 조사대상 브랜드 중 프랜차이즈경영 베이커리는 파리바게트, 뚜레주르로 선정하였으며, 독립경영 베이커리는 프랜차이즈 경영이 아닌 개인사업체로 대구의 삼송빵집, 부산의 옵스, 대전의 성심당을 선정하였다. 연구결과, 베이커리 전문점의 브랜드 증거 중에서 가격과 서비스스케이프, 핵심서비스, 직원서비스가 브랜드 신뢰에 긍정적인 영향을 미치는 것으로 나타났다. 브랜드 신뢰는 브랜드 충성도에 긍정적인 영향을 미치는 것으로 나타났다. 브랜드 증거와 브랜드 신뢰 간의 인과관계에서 경영형태에 따른 차이는 부분적으로 존재하는 것으로 조사되었다. 결과적으로 베이커리 전문점에 대한 긍정적인 신뢰 형성과 충성도 강화에 영향을 미치는 브랜드 증거와 경영형태의 조절 역할을 규명하였다. This study aims to empirically analyze the effect of brand evidence recognized by customers who use the bakery shops on consumer s brand trust and loyalty, and based on the results, present a marketing strategic measure by analyzing the consumer s awareness and loyalty to bakery shop brands in detail Paris Baguette and Taus Les Jours were selected as the franchise bakery brands and Samsong Bakery in Daegu, Ops Bakery in Busan, and Sungsimdang in Daejeon were selected as private business for independent bakeries in the survey. As a result of this research, it was found that price, servicescape, core service and employee service in brand evidence of bakery shops had a positive effect on brand trust. It was found that brand trust had a positive effect on brand loyalty. In a correlation between brand evidence and brand trust, a difference according to business type was verified and the results showed that there was a partial difference due to a business type. In conclusion, it investigated roles of brand evidence and moderating of management type which affected positive trust formation and reinforcement of loyalty toward bakery shops.

기능적 장애 개념과 중증 장애인 기준의 타당성

이석원(Suk-Won Lee),정희정(Hee-Jeong Cheong) 한국정책분석평가학회 2008 政策分析評價學會報 Vol.18 No.4

One of the most frequently discussed problems regarding employment quota system for disabled workers in Korea is that this system severely handicapped people are much less likely to be employed than less severly handicapped people are. Regarding this matter, active debates are made in academia focusing on establishing a new disability standard with taking account of vocational disability. In this study, we attempt to analyze the validity of disability standard in current law. We used the data from Survey on Disabled Workers for 2005 and compared the severe disability defined with functional standard and that defined with medical standard. The analysis findings indicate that severely disabled workers under the definition of functional disability are less likely to conduct their tasks without difficulties compared to those under the definition of medical disability. As the findings imply, Korean government should consider setting up new disability assessment system based on the notion of vocational or functional disability.

로봇 냉각을 위한 수냉식 냉각판의 성능 평가

이석원(Suk Won Lee),강상우(Sarng Woo Karng),황규대(Kyudae Hwang),김서영(Seo Young Kim),리광훈(Gwang Hoon Rhee) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.3

The increase of system weight due to installation of cooling devices adds electrical and mechanical loads of humanoid robot, and in return, results in much heat. Therefore, the weight of cooling system is a critical issue for robot cooling. In this study, we propose non-metallic cold plates to deal with such problems. We compare thermal performances between one metallic cold plate and five different types of non-metallic cold plates. A metallic cold plate is totally made of copper. Five non-metallic PC (polycarbonate) cold plates, which are designed to reduce the overall weight of robot cooling system, are composed of a polycarbonate cover with different types of base plate. The overall heat transfer coefficients per unit mass and thermal resistances are obtained for the cold plates. The metallic cold plate shows the best thermal performance. It is interesting to note that the PC cold plate with an aluminum base plate with 18 channels shows the best overall heat transfer coefficient per unit mass. Most polycarbonate cold plates display fairly comparable thermal performance with more reduced system weight compared to the metallic cold plate.