• Structural Engineering and Mechanics
• /
• 제9권5호
• /
• pp.417-432
• /
• 2000

A comprehensive analytic study has been conducted to investigate the instability problems of metal-plate-connected (MPC) joints in light frame trusses. The primary objective in this study is to determine the governing factors that constitute the buckling of the metal connectors and their effects on the structural response of joints. Another objective is to recommend design curves for the daily structural design of these joints. The numeric data presented in this paper has emerged from a broad base that was founded on over 350 advanced computer simulations, and was supported by available experimental results obtained by others. This basic-to-applied research includes practical engineering parameters such as size of gaps, shear lengths, gauge (plate thickness) of connectors, size of un-braced areas, failure modes, and progressive disintegration of joints. Square-end members have been emphasized though the results cover the custom-made fitted joints. The results indicate that chord shears cause and dominate the buckling of MPC joints, and the shear length has a more pronounced effect than the size of gaps. Further, large gauges and small un-braced areas improve the buckling response. Several practical recommendations have been suggested throughout the paper such as keeping the ratio of gap/shear length below 3/4 for improving the buckling strength. The study reveals that multi-area joints should not be simplified as single web-to-chord MPC joints such as keeping the ratio of gap/shear length below 3/4 for improving the buckling strength, even where one web is in tension and the other in compression. Finally, the results obtained from this study favorably agree with experimental data by others, and the classic buckling theories for other structural components.

• 과학기술학연구
• /
• 제10권1호
• /
• pp.27-71
• /
• 2010

과학적 창의성은 새롭고 중요한 과학적 사실, 방법, 이론, 설명, 측정기구와 이를 낳는 활동이다. 지금까지 창의성에 관한 연구가 많이 이루어졌지만, 대학의 실험실에서 팀단위의 협동 연구에서 발현되는 과학적 창의성에 대한 이해는 부족하다. 본 논문은 우리나라에서 대표적으로 창의적인 실험실로 간주되는 서울대학교 RNA 유전체학 연구실에 대한 미시적, 경험적 참여관찰과 이론적 분석을 통해 실험실의 창의성을 구성하는 요소를 찾아내는 것을 목표로 한다. 창의적인 업적은 순간적인 영감에 의해서 이루어지는 것이 아니라 복잡하고 지속적인 진화의 과정을 필요로 하며, 이 과정에서 다양한 지식과 능력을 지닌 연구자들에게 맞는 분업과 협동 체계가 중요하게 요구된다. 또한 이러한 구조를 활성화 하는 실험실 문화와 실험실 책임자의 리더십이 중요하게 작용함을 관찰할 수 있었다.

• 한국산학기술학회논문지
• /
• 제19권9호
• /
• pp.84-90
• /
• 2018

철도차량의 거동을 해석하기 위하여 다물체 동역학 모델을 구성함에 있어 현가시스템을 구성하는 스프링, 댐퍼와 같은 현가요소에 대한 스프링강성이나 감쇠계수와 같은 물성치 파악은 매우 중요하다. 그 중 1차, 2차 현가시스템에 주로 활용되고 있는 코일스프링에 대한 동역학 모델을 구성함에 있어 축방향 강성은 도면이나 설계자료에 명확하게 명시되어 있지만 횡방향에 대한 물성은 명시되어 있지 않아 동역학 해석 모델 구성에 어려움을 안고 있다. 따라서 본 논문에서는 철도차량의 현가시스템에 폭 넓게 적용되고 있는 코일스프링에 대한 횡강성을 해석하기 위한 모델에 대하여 검토하고자 한다. 코일스프링 시료에 대한 횡강성을 해석하고자 유한요소해석 방법을 수행하였고 Krettek와 Sobczak의 코일스프링 횡강성 해석모델을 적용하여 수치해석을 수행하였다. 그리고 코일스프링 시료를 대상으로 횡강성 특성시험을 수행하여 해석모델과의 적합성을 검토하였다. 시험결과와 비교한 결과, Krettek와 Sobczak의 코일스프링 횡강성 해석모델을 적용하고 보정계수를 수정한 결과가 시험결과에 근사한 결과를 얻을 수 있었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
• /
• pp.470-470
• /
• 2012

Organic thin film transistors (OTFTs) backplane constitute the active elements in new generations of plastic electronic devices for flexible display. The overall OTFTs performance is largely depended on the properties and quality of each layers of device material. In solution based process of organic semiconductors (OSCs), the interface state is most impediments to preferable performance. Generally, a threshold voltage (Vth) shift is usually exhibited when organic gate insulators (OGIs) are exposed in an ambient air condition. This phenomenon was caused by the absorbed polar components (i.e. oxygen and moisture) on the interface between OGIs and Soluble OSCs during the jetting process. For eliminating the polar component at the interface of OGI, the role of high vacuum seasoning on an OGI for all solution processable OTFTs were studied. Poly 4-vinly phenols (PVPs) were the material chosen as the organic gate dielectric, with a weakness in ambient air. The high vacuum seasoning of PVP's surface showed improved performance from non-seasoning TFT; a $V_{th}$, a ${\mu}_{fe}$ and a interface charge trap density from -8V, $0.018cm^2V^{-1}s^{-1}$, $1.12{\times}10^{-12}(cm^2eV)^{-1}$ to -4.02 V, $0.021cm^2V^{-1}s^{-1}$, $6.62{\times}10^{-11}(cm^2eV)^{-1}$. These results of OTFT device show that polar components were well eliminated by the high vacuum seasoning processes.

• 대한조선학회논문집
• /
• 제45권4호
• /
• pp.441-454
• /
• 2008

Shipyard design and equipments layout problem, which are directly linked with the productivity of ship production, is an important issue serving as reference data of production plan for later massive production of ships. So far in many cases, design of a shipyard has been relying on the experienced engineers in shipbuilding, resulting in sporadic and poorly organized processes. And thus, economic losses as well as trials and errors in that accord have been pointed out as inevitable problems. This paper extracts a checklist of major elements to fine tune the shipbuilding yard designing process and the input/output data based on the simulation based shipbuilding yard layout designing framework and methodology proposed in existing researches, and executed initial architecture to develop software that integrates all the relevant processes and designing tools. In this course, both user request and design data by the steps are arranged and organized in the proposed layout design template form. In addition, simulation is done based on the parent shipbuilding process planning and scheduling data of the ship product, shipbuilding process and work stage facilities that constitute shipbuilding yard, and design items are verified and optimized with the layout and equipment list showing optimal process planning and scheduling effects. All the contents of this paper are based on simulation based shipbuilding yard layout designing methodology, and initial architecture processes are based on object oriented development methodology and system engineering methods.

• 한국대기환경학회지
• /
• 제21권1호
• /
• pp.131-140
• /
• 2005

To investigate secondary carbonaceous species within PM$_{10}$ and PM$_{2.5}$ in Seoul urban Metropolitan Area (SMA), Korea. atmospheric particulate matters samples were collected at two sites of SMA at UOS (The University Of Seoul station) sites and IHU (InHa University of Incheon station) during the period of 4 to 14 January and 12 to 22 May, 11 to 15 August 2004, and their characteristics were qualitatively discussed. during January and May and August of 2004. Daily average mass concentration 0.095 mg/㎥ in PM$_{10}$ and 0.053 mg/㎥ in PM$_{2.5}$ for mass respectively. were observed in SMA. The concentrations of carbonaceous species contributed 18.4% and 16.4% of PM$_{2.5}$ and PM$_{10}$ during the sampling period, respectively, of which OC accounted for 68% and 52% more of the total carbon (TC). OC and EC concentrations and their mass percentages were higher in PM$_{2.5}$ than in PM$_{10}$ which could be attributed to generation process. Organic aerosols would constitute up to 38% of PM$_{2.5}$ based on the evaluation of 1.6 for the ratio of OC to organic particulate. Secondary organic carbon (SOC) were estimated to be more than 13% and up to 68% of total OC based on the minimum OC/EC ratio of 1.06/1.11 using least square method. Comparisons of OC and EC with trace elements. As results of carbonaceous species analysis, the dominant factor in view of fine particle (PM$_{10}$/PM$_{2.5}$) is primary emission source such as mobile, fossil fuel combustion etc. during winter time in SMA. But in summer periods, remarkable fine particle increasing factor was secondary organic carbon dependent to photochemical reaction. reaction.n. reaction.

• 디지털융복합연구
• /
• 제18권3호
• /
• pp.357-362
• /
• 2020

본 연구는 추상적인 국내 책 표지 디자인의 신화를 분석함으로써, 롤랑 바르트의 기호학적 방법론의 적용 가능성을 알아보고 수용자들은 어떻게 받아들이는지 선호도 조사까지 시행하였다. 연구대상은 국내 출판사인 열린책들에서 30주년 기념으로 출간되었던 시리즈 중 <개미>와 <향수>를 선정하였다. 책표지디자인의 의미작용 분석 결과, 첫째, 롤랑 바르트의 기호학적 접근법은 추상적인 책표지디자인을 구성하는 시각적 요소의 기호현상을 파악하기에 적합한 도구임을 확인하였다. 둘째, 수용자들은 추상적인 형태의 디자인이 전하는 바를 잘 전달받고 있었지만 선호도 부분에 있어서는 개인적인 차이를 보여 확실한 결과를 얻기 어려웠다. 본 연구는 책표지 디자인에 나타나는 내면적 의미의 중요성과 함께 그래픽 디자이너들에게 전달자와 수용자 간의 상호작용이 이루어지도록 노력해야 한다는 시사점을 제공한다.

• 한국환경성돌연변이발암원학회:학술대회논문집
• /
• 한국환경성돌연변이발암원학회 2002년도 Current Trends in Toxicological Sciences
• /
• pp.25-35
• /
• 2002

Transcription factor Nrf2 is essential for the antioxidant responsive element (ARE)-mediated induction of phase II detoxifying and oxidative stress enzyme genes. Detailed analysis of differential Nrf2 activity displayed in transfected cell lines ultimately led to the identification of a new protein, which we named Keap1, that suppresses Nrf2 transcriptional activity by specific binding to its evolutionarily conserved amino-terminal regulatory domain. The closest homolog of Keap1 is a Drosophila actin-binding protein called Kelch, implying that Keap1 might be a Nrf2 cytoplasmic effector. We then showed that electrophilic agents antagonize Keap1 inhibition of Nrf2 activity in vivo, allowing Nrf2 to traverse from the cytoplasm to the nucleus and potentiate the ARE response. We postulate that Keap1 and Nrf2 constitute a crucial cellular sensor for oxidative stress, and together mediate a key step in the signaling pathway that leads to transcriptional activation by this novel Nrf2 nuclear shuttling mechanism. The activation of Nrf2 leads in turn to the induction of phase II enzyme and antioxidative stress genes in response to electrophiles and reactive oxygen species.

• International Journal of Costume and Fashion
• /
• 제8권2호
• /
• pp.50-64
• /
• 2008

The purpose of this study is to classify Avatar fashion style through analysis of on-line Avatar Mall and to propose color pallette and fashion contents from fashion color analysis. The literature research focused on investigating the notion, characters and types of Avatar and relation of Avatar and self-image, clothing image and color image. In data research, 4 on-line portal sites Avatar Malls were analyzed and Avatar fashion style was classified. In addition, Avatar clothing color was analyzed. The research of this study are as follows: Firstly, Avatar in the cyber space represents 'me' of the real states. Avatar fashion helps to represent Avatar Image and clothing makes human image and identity as a social sign. Color helps to constitute clothing impression and human image, therefore clothing and color are the important elements to express self-image through Avatar in the cyber space. Secondly, Avatar Malls of 4 on-line portal sites are very similar and confuse Avatar users because of no standard of fashion style classification. Accordingly, the standard of fashion style classification should be made by a fashion expert, and the specific characters of every on-line portal site should be emphasized. Thirdly, as a result of the analysis of Avatar's clothing, the clothing is divided into a real world clothing and an imaginary world clothing. There are daily clothes, uniform, event clothes, story clothes and fantasy clothes. As a result of the color analysis of Avatar clothing, White, Red, Red Purple colors and bright and vivid tone are generally used for Avatar clothing. This study is significant to classify Avatar fashion style systematically, to notify sensitive and delicate users' sign and to make Avatar fashion image emotional and high-quality.

• 과학기술학연구
• /
• 제12권1호
• /
• pp.79-106
• /
• 2012

온라인게임은 인간과 기계의 상호작용적 실행을 연결하여 서사적 구조를 완성해가는 프로그램이다. 실재성이 발생할 수 있는 상황-맥락과 그 맥락적 관계를 생산하는 실행들게임 참가자들은 사소한 여가활동으로 게임을 시작하지만 곧 진지해지곤 한다. 게임이용자들은 그 세계에서 일종의 실재성을 경험하는 것이다. 이 논문은 "무엇이 실재인가?"라는 전통적인 물음을 하는 대신 "어떻게 실재가 발생하는가?"라는 새로운 물음을 전개해나갈 것이다. 특히 과학기술학의 이론적 개념을 정보통신기술 위에서 작동하는 이미지(표상)에 적용하여, 에 초점을 둔다. 이용자들과 게임시스템은 상호적 실행을 통하여 서로의 관계를 자기-참조적으로 강화해가며 고유한 시-공간 프레임(space-time frame)을 구성할 수 있다. 그러한 프레임은 기술적 텍스트적 표상적 역사적 문화적 경제적 사회적인 차원의 이질적인 실행들이 뒤엉킨 물질-기호적 장(material-semiotic field)이다. 그 안에서 게임이미지는 자신의 위치를 가지게 되고, 그 순간 두께를 가진 실재로서 간주된다. 이로써 정보통신기술이 매개하는 전자적 표상(텍스트나 이미지)에 대한 우리의 경험은 우리가 참여하는 시-공간 프레임에 의존한다는 함축을 확인할 수 있다.