차동 구륜이동로봇의 기구학적 보정과 제어기 설계

김환,백상욱,박세승 조선대학교 전자정보통신연구소 2002 電子情報通信硏究所論文誌 Vol.5 No.1

This paper presents a method for reducing odometry errors caused by kinematic imperfections in a differential drive mobile robot. And a new velocity trajectory is proposed that compensates for orientation error due to acceleration constraints on motor controllers. According to this velocity trajectory, the wheel velocity of one out of two driven wheels may be changed by the traveled distance of the mobile robot. It is shown that a wheeled mobile robot can't move along a straight line exactly, even if kinematic imperfections are corrected perfectly. and this phenomenon is attributable to acceleration constraints on motor controllers. We experiment on a wheeled mobile robot with 2 d.0.f. and discuss the results.

어메니티플랜의 제도화 방안에 관한 연구

김세용,이재준,김영환,권용우,황희연 대한건축학회 2003 대한건축학회논문집 Vol.19 No.1

The importance of the quality of urban life is being increased now. Citizens have been looking for the pleasant places and have a tendency for getting amenity in a certain place. In some cities, an amenity plan has been made to promote urban amenities and to get rid of dis-amenities. We believe that amenity would be more important planning elements in the future. This study proceeded to get some guidances for amenity plan as followings. First, the literature study for amenity and amenity plan was carried out. Second, questionary survey was executed for figuring out the experts' opinion. Third, the suggestions for making amenity plan were developed.

타감작용에 의한 식생관리 방안에 관한 기초연구 : 잔디관리를 중심으로

서주환,김세천,淺野義人,박봉주 韓國植物·人間·環境學會 1998 인간식물환경학회지 Vol.1 No.2

본 연구는 난지형잔디에 의한 한지형잔디의 발아억제와 한지형잔디에 의한 잡초발생억제 등 일련의 타감작용에 의한 생태적인 잔디관리를 위한 기초자료를 제공하고자 실시되었다. turf관찰에서는 overseeding한 KB와 TF의 발아 개체수는 base의 나지형잔디에 의한 차가 거의 나타나지 않았으나, 들잔디의 KB overseeding에 있어서는 유의성이 관찰되었다. 1개체당 평균 건조중량은 base의 난지형잔디에 의한 차가 있었으며, 특히 센티피드그래스의 KB 및 TF overseeding구에서 가장 낮게 나타나 높은 생육 억제현상이 관찰되었다. 나지형잔디 5종류의 건조엽분말 50g을 이용한 pot실험에서 센티피드그래스구와 들잔디구 및 세인트어거스틴그래스구의 KB 및 TF의 발아율이 낮게 관찰돼 타감작용이 강한 것으로 나타났으며, 버뮤다그래스구와 버팔로그래스구는 양호한 발아율이 나타났다. 센티피드그래스 분말 (0, 25, 50, 75g)에 의한 KB, TF의 발아율 및 평균 건조중량을 조사한 결과 KB와 TF 발아율 및 평균 건조중량은 센티피드그래스의 건조분말이 증가할수록 감소하는 경향이 나타났다. The purpose of this study is to offer the basic materials for the ecological management of grass through allelopathy such as inhibition of cool-season turfgrasses germination by warm-season turfgrasses and retardation of weed by cool-season turfgrasses. In the observation of turf, the number of germinating Poa pratensis L. and Festuca arundinacea Schreb. was almost same but in the Poa pratensis L. overseeding, it showed significant difference. The dry weight of each individual was different by the kind of warm-season turfgrasses. Especially it is ascertained high in the Poa pratensis L.and Festuca arundinacea Schreb. overseeding of Eremochloa ophiuroides (Munro) Hack. so depression effect was showed. It was confirmed in the experiment by 50g, flour of five kinds of warm-season turfgrasses that allelopathy effected the germination percentage of Poa pratensis L. and Festuca arundinacea Schreb. slight in the plot of Eremochloa ophiuroides (Munro) Hack, Zoysia japonica Steud, Stenotaphrum secundatum (Walt) Kuntze. And the polt of Cymodon dactylon (L) Pers. and Buchloe dactyloides (Nutt.) Engeim. showed good germination. As a result of investigation of the germination percentage and the dry average weight of Poa pratensis L. and Festuca arundinacea Schreb. by Eremochloa ophiuroides (Munro) Hack. flour(0, 25, 50, 75g), the dry average weight and germination percentage of Poa pratensis L. and Festuca arundinacea Schreb. were reduced as much as Eremochloa ophiuroides (Munro) Hack. increased.

자발성 기흉을 동반한 폐림프관평활근종증 1예

안용환,정종훈,김소영,김휘정,김학렬,양세훈,최순호,문형배,조향정,정은택 圓光大學校 醫科學硏究所 2005 圓光醫科學 Vol.20 No.1

외부광궤환에 의한 레이저 다이오드의 출력특성

이세영,오차환,김필수,황의중 漢陽大學校 自然科學硏究所 1997 自然科學論文集 Vol.16 No.-

외부 광궤환 반도체 레이저의 출력 특성을 비율방정식의 수치해를 이용하여 분석하였다. 출력의 세기와 위상과 전자밀도를 시간에 대한 함수로 알아보았다. 또한 bifurcation diagram과 phase diagram을 통하여 궤환비율 k에 따른 레이저의 동작 특성을 조사하였다. 궤환광이 없을때는 이완발진이 감쇄한 후 안정한 출력특성이 나타나지만 되먹임 비율이 증가하면서 안정한 해의 갯수가 증가하다가 ??????이상의 매우 강한 광궤환에서는 출력특성이 극도로 불규칙해지고 무수히 많은 해를 갖는 혼돈현상이 나타남을 알 수 있었다. The output characteristics of a laser diode with external optical feedback were analyzed by numerical solutions of rate equations. The output power, phase and carrier density were plotted as a function of time. Dynamics of external cavity laser were investigated by the bifurcation diagram and the phase diagram with respect to the feedback rate k. If there was no feedback, relaxation oscillation reduced and laser showed stable output. For increasing feed back level, the number of stable state was increased. In very strong feedback rate above ??????, laser output showed extremely unstable and chaotic behavior.

웹 사이트 재방문 의도에 영향을 미치는 요인

이시환,정세현,김용겸 한국인터넷비즈니스학회 2001 인터넷비지니스연구 Vol.2 No.1

본 연구는 웹 사이트 사용자들의 인지도에 영향을 주는 요인이 무엇인가를 밝히고자하는데 초점을 두고, 웹 사이트 재방문(재사용) 의도에 영향을 주는 정보시스템의 질, 정보의 질, 인지된 사용의 용이성, 인지된 유용성, 웹 사이트 선호, 그러고 컴퓨터 경험 및 성의 조절효과를 검증하고자 했다. 본 연구가설의 검증결과를 요약하면, 다음과 같다. 첫째, 정보시스템의 질과 정보의 질은 인지된 사용의 용이성에 유의하게 陽(+)의 영향을 미치는 것으로 나타났다. 그러나, 이들 사이에 조절변수로 사용된 컴퓨터 경험은 조절 변수의 역할을 하지 못하고, 오히려 독립변수의 역할을 하는 것으로 나타났다. 둘째, 인지된 사용의 용이성이 인지된 유음성에 유의하게 陽(+)의 영향을 미치는 것으로 나타났다. 또한, 인지된 사용의 용이성이 웹 사이트 선호에 유의하게 陽(+)의 영향을 미치는 것으로 나타났으나, 이들 사이에 조절변수로 사용된 성(gender)은 조절변수의 역할을 하지 못했다. 셋째, 웹 사이트 선호가 웹 사이트 재방문 의도에 유의하게 陽(+)의 영향을 미치는 것으로 나타났으나, 이들 사이에 조절변수로 사용된 성(gender)은 조절변수의 역할을 하지못했다. This study addresses why users accept or reject a Web site and how user’s acceptance is affected by the features(i.e. IS quality and information quality) provided by a Web site. In considering such an issue, it is believed that IS quality and information quality are very influential factors in determining the user’s beliefs of usefulness and ease of use of a Web site. The user’s perceptions of a Web site are considered by applying the technology acceptance model(TAM). TAM has been widely used to predict the acceptance of a new technology, such as the acceptance of new S/W packages. It postulates that the two variables, perceived usefulness and perceived ease of use. In this study, perceived usefulness and ease of use of the Web site, preference for the Web site, and willingness to revisit the Web site are used to measure beliefs, attitude and intention, respectively. Since the design of a Web site is within the framework of IS, it is postulated that the beliefs about a Web site(i.e. perceived ease of use) is a function of the IS quality and information quality. The following are the summary of the test results of the research hypotheses. First, IS quality and information quality are posited to exert simultaneous, direct, and linear influences on perceived ease of using a Web site. Perceived ease of use of a Web site can be statistically significantly predicted by two paths from IS quality and information quality. But, computer experience isn’t moderated between the IS quality and information quality and the perceived ease of use. Second, perceived usefulness is statistically significantly predicted by one path from perceived ease of use. Third, preference for a Web site is statistically significantly predicted by on path from perceived usefulness, But, gender isn't moderated between the perceived usefulness and the preference for a Web site. Fourth, intention to revisit a Web site is statistically significantly predicted by one path from preference for a Web site. But, gender isn't moderated between the preference for a Web site and the intention to revisit a Web site. Conclusively, the significant relationships may be attributed to the possible causal effect chains, that is IS quality and information quality → perceived ease of use → perceived usefulness → preference for a Web site → intention to revisit a Web site → (actual use) as similarly shown in Fig. 1.

런닝머신 프레임의 구조해석

이종선,김세환,이현곤 호서대학교 반도체제조장비국산화연구센터 2000 학술대회 자료집 Vol.2000 No.1

This study is object to structural analysis of running machine frame. The finite element model was developed to compute the stress, strain and natural frequency for running machine frame. For structural analysis using result from FEM Code. In other to structural analysis of running machine frame, many variables such as load condition, boundary condition and weight condition are considered.

Genetic diversity of tomato-infecting Tomato yellow leaf curl virus (TYLCV) isolates in Korea

Kim, Sue Hoon,Oh, Sung,Oh, Tae-Kyun,Park, Jae Sung,Kim, Sei Chang,Kim, Seong Hwan,Kim, Young Shik,Hong, Jeum Kyu,Sim, Sang-Yun,Park, Kwon Seo,Lee, Hwan Gu,Kim, Kyung Jae,Choi, Chang Won Springer-Verlag 2011 Virus genes Vol.42 No.1

Organic Light‐Emitting Diodes with 30% External Quantum Efficiency Based on a Horizontally Oriented Emitter

Kim, Sei‐,Yong,Jeong, Won‐,Ik,Mayr, Christian,Park, Young‐,Seo,Kim, Kwon‐,Hyeon,Lee, Jeong‐,Hwan,Moon, Chang‐,Ki,Brü,tting, Wolfgang,Kim, Jang‐,Joo WILEY‐VCH Verlag 2013 Advanced Functional Materials Vol.23 No.31

<P><B>Abstract</B></P><P>High‐efficiency phosphorescent organic light‐emitting diodes (OLEDs) doped with Ir(ppy)<SUB>2</SUB>(acac) [bis(2‐phenylpyridine)iridium(III)‐acetylacetonate] in an exciplex forming co‐host have been optically analyzed. This emitter has a preferred orientation with the horizontal to vertical dipole ratio of 0.77:0.23 as compared to 0.67:0.33 in the isotropic case. Theoretical analysis based on the orientation factor (<I>Θ</I>, the ratio of the horizontal dipoles to total dipoles) and the photoluminescence quantum yield (<I>q</I><SUB>PL</SUB>) of the emitter predicts that the maximum external quantum efficiency (EQE) of the OLEDs with this emitter is about 30%, which matches very well with the experimental data, indicating that the electrical loss of the OLEDs is negligible and the device structure can be utilized as a platform to demonstrate the validity of optical modeling. Based on the results, the maximum EQE achievable for a certain emitting dye in a host can be predicted by just measuring <I>q</I><SUB>PL</SUB> and <I>Θ</I> in a neat film on glass without the need to fabricate devices, which offers a universal plot of the maximum EQE as a function of <I>q</I><SUB>PL</SUB> and <I>Θ</I>.</P>

Chronic intermittent hypoxia augments lipopolysaccharide induced acute lung injury

( Sei Won Kim ),( In Kyoung Kim ),( Hee Young Kwon ),( Sung Bae Cho ),( Jong Min Lee ),( Jick Hwan Ha ),( Hyeon Hui Kang ),( Seok Chan Kim ),( Sang Haak Lee ) 대한결핵 및 호흡기학회 2018 대한결핵 및 호흡기학회 추계학술대회 초록집 Vol.126 No.-

Obstructive sleep apnea (OSA) is characterized by repetitive upper airway collapse during sleep, causing chronic intermittent hypoxia (CIH). OSA affects 2-5% of the middle-aged population and is associated with significant morbidity and mortality. In intensive care unit, considerable numbers of patients with acute lung injury (ALI) have underlying OSA. However, little is known regarding the effects of OSA on the clinical course of ALI. This study is aimed to evaluate the impact of CIH on inflammation, fibrosis and related pathway in a murine model of ALI. Seven-to-eight week-old male, C57BL/6J mice were used. The mice were divided into two groups and exposed to room air (RA) or CIH. During 4 weeks, the CIH group was exposed to a 30 s RA/hypoxia (approximately fractional inspired O2 7±0.5%) cycle for 8 hours a day. After 4 weeks, each group was divided into two additional groups with intratracheal lipopolysaccharide (LPS, 0.5 mg/kg) or saline exposure. In CIH group with LPS exposure, lung wet/dry ratio and lung injury score were higher than other three groups. Level of hyproxyproline, TGF-beta, VEGF and collagen deposition were also higher in CIH group with LPS exposure compared to other groups. From the cell differentiation of bronchoalveolar lavage, CIH group with LPS exposure showed significantly higher number of total cell and neutrophil compared with other groups, especially compared with RA group with LPS exposure (p<0.001, respectively). These results suggest that CIH may aggravate inflammation and fibrosis in LPS induced ALI, resulting more damage.