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비전 인식 기반의 검사 기능을 갖는 FDM 방식 3D 프린터 시스템 개발
송순호(Sunho Song),이해연(Hae-Yeoun Lee) 한국정보기술학회 2020 한국정보기술학회논문지 Vol.18 No.10
3D printing is a popular technology that allows anyone to quickly and easily create products at home or office, but product errors can occur due to various causes during time consuming and expensive 3D printing. In this paper, In this paper, we describe the development of an FDM type 3D printer that improves performance by inspecting in real-time through vision recognition to determine whether errors occur during 3D printing. A system structure for error inspection and control and a vision recognition algorithm that detects errors by comparing real-time acquired images and expected model output images are presented. Also, since recognition errors may occur due to reflection of external lights during actual printing, a stable image acquiring method using shielding and LED lighting is explained. An FDM type 3D printer with vision recognition based inspection function was developed, and through performance analysis, it was confirmed that 100% recognition is possible in abnormal printing whose size is 2mm or more.
Song, Keunkyu,Yang, Wooseok,Jung, Yangho,Jeong, Sunho,Moon, Jooho The Royal Society of Chemistry 2012 Journal of materials chemistry Vol.22 No.39
<P>We studied high-<I>k</I> soluble yttrium oxide dielectrics for high performance oxide thin film transistors (TFTs). The electrical characteristics of yttrium oxide show leakage current density as less than 10<SUP>−6</SUP> A cm<SUP>−2</SUP> at 2 MV cm<SUP>−1</SUP> regardless of annealing temperature and a high dielectric constant of nearly 16. For the first time, all solution-processed fully transparent ZnO-TFTs based on spin-coated YO<SUB><I>x</I></SUB> gate dielectric layers with a small interfacial trap density and high capacitance were demonstrated, exhibiting a field-effect mobility of 135 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP>, a threshold voltage of 1.73 V, and an on–off current ratio of 5.7 × 10<SUP>7</SUP> as well as low-voltage operation. In addition to microstructural and electrical analyses for solution-processed YO<SUB><I>x</I></SUB> dielectrics, we investigated the influences of dielectric–semiconductor interfacial quality on device parameters. Our results suggest that solution-processable fully transparent oxide TFTs have the potential for low-temperature and high-performance application in transparent, flexible devices.</P> <P>Graphic Abstract</P><P>All-solution-processed fully transparent ZnO thin film transistors on glass substrates were demonstrated for the first time. The resulting device exhibits an exceptionally high field-effect mobility of 135 cm<SUP>2</SUP> V<SUP>−1</SUP> s<SUP>−1</SUP> and an on–off current ratio of 5.7 × 10<SUP>7</SUP> as well as low-voltage operation. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c2jm34162j'> </P>
Interval Disaggregation with Product Life Cycles and Constraints
Sunho Lee,Cheol Ryu,Sang Kyun Cha,Kunsoo Park,Jungsuk Oh,Kihong Kim,Changbin Song 한국정보과학회 2018 Journal of Computing Science and Engineering Vol.12 No.2
Disaggregation is a common operation in business applications. One of the main disaggregation operations in use has been referential disaggregation, but a more advanced disaggregation operation called interval disaggregation has recently been introduced. In this paper we significantly generalize the model of interval disaggregation in the previous work. Through nonlinear regression, we apply interval disaggregation to the products with product life cycle curves. We implemented interval disaggregation with product life cycles as a relational operator in a commercial in-memory database system and did experiments on real-world data. Our experiments show that interval disaggregation with product life cycles outperforms previous disaggregation operations. We also present a technique that combines constraints such as factory capacities into interval disaggregation, so that we can find a product mix that maximizes profit subject to the constraints.
Development of Unmanned Ground Vehicle for Multi Agent systems
Sunho Lee,Bongsob Song,Youngho Shin,Jaeyoon Byun 제어로봇시스템학회 2009 제어로봇시스템학회 국제학술대회 논문집 Vol.2009 No.8
An engineering approach to designing an unmanned ground vehicle (UGV) operating in multi agent systems is presented in the paper. The objective of multi agent systems is to surveil allocated regions for environmental monitoring, e.g. forest fire. The UGV is designed to work as a single agent to gather environmental information for surveillance. In this research, a Hardware-In-the-Loop Simulation (HILS) technique is used to save development cost and human effort. That is, one of the UGVs is developed in reality and the others are generated virtually for HILS. Furthermore, a detailed account for the development of a multi agent system including hardware layouts, software architecture, and communication among a distributed system is presented. Finally the feasibility of this platform is validated experimentally via HILS.
해상풍력발전기 하부구조물의 세굴현상에 관한 파라미터 변화 연구
박선호(Sunho Park),송성진(Seongjin Song),왕해청(Haiqing Wang),정태환(Taehwan Jung),신윤섭(Yunsup Shin) 한국해양환경·에너지학회 2017 한국해양환경공학회 학술대회논문집 Vol.2017 No.4
고정식 해상풍력발전기의 경우 조류 및 파랑으로 인해 하부구조물에서 세굴현상이 발생하여 구조적 안정성에 심각한 손상을 발생시키는 사례들이 보고되고 있다. 이에 본 논문에서는 고정식 해상풍력발전기의 하부구조 형상 변화에 따른 세굴현상을 해석을 진행하였다. 해석은 소스코드가 공개된 라이브러리인 OpenFOAM을 사용하였다. 2차원 석션버켓에 대한 해석을 진행하여 수치방법을 선정하였다. 석션버켓의 매설 높이와 수심의 변화에 따른 해석을 진행하여 유동장 변화 및 세굴현상을 해석하였다. In the case of fixed offshore wind turbines, scouring phenomena have been reported around sub-structures due to the currents and the waves, causing serious damage to the structural stability. In this paper, a parametric study for various sub-structures of the fixed offshore wind turbine was carried out to investigate the effect on the scouring phenomena. The open source libraries, called OpenFOAM, were used. From the two-dimensional analysis for a suction bucket, the numerical methods were selected. The influence of stick-up height of the suction bucket and depths of the sea water on the scouring phenomena was studies.
소형 디젤 차량에서 LNT 시스템 제어를 통한 DeNO<SUB>x</SUB> 효율 개선에 관한 연구
유선호(Sunho Yoo),전광민(Kwang Min Chun),송순호(Soonho Song) 한국자동차공학회 2010 한국자동차공학회 학술대회 및 전시회 Vol.2010 No.11
Lean NOx Trap technology is a promising method to reduce nitrogen oxides in lean exhaust condition. The technology operates by storing NOx during lean exhaust conditions and then, under rich exhaust conditions, releasing and reducing the stored NOx to nitrogen. The reduction process is called regeneration and typically involves some additional fuel use or fuel penalty. In this study injection timing and injection quantity are optimized for minimize fuel penalty and maximize NOx conversion efficiency.
Choi, Sunho,Jang, Boyun,Kim, Joonsoo,Song, Heeun,Baek, Taehyeon,Han, Moonhee Elsevier 2015 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.122 No.-
<P><B>Abstract</B></P> <P>Thin silicon (Si) wafers with thickness of 100–140μm were obtained by using a multi-wire slicing process with a SiC slurry. We investigated the process yields of wafer slicing as well as physical/electrical properties of the sliced wafers with various thicknesses. As the wafer thickness decreases, the process yield abruptly decreased due to wafer breakage during the slicing process, and conventional polishing the brick surface was not enough to gain a considerable process yield. However, elimination of defects on the brick surface by mirror polishing resulted in an 83.1% enhancement of yield even for wafers with a thickness of 100μm. The number of wafers obtained was even higher than that of conventional 180μm-thick wafers (479 vs. 415 wafers in this research). Investigation of the microstructure of brick surfaces revealed that surface defects on bricks were main parameter to determine the yield of slicing process. Surface defects containing the micro-cracks introduced residual stress, which decreased the slicing process yield especially for thinner wafers. From measurements of physical and electrical properties, it was revealed that the relative total thickness variations (TTVs) and bowings increased and the characteristic fracture strength of sliced wafer and conversion efficiencies decreased as the wafer thickness decreased. For the wafer with thickness of 100μm, the relative TTV and bowing were 14.1% and 22.5mm, respectively. The conversion efficiency of a solar cell using this wafer was 17.6%, while that of a conventional Si solar cell using a 180μm-thick wafer was 18.4%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Thin silicon wafers with thickness of 100–140μm were sliced by multi-wire slicing. </LI> <LI> Physical and electrical properties of thin Si wafers were investigated. </LI> <LI> Subsurface defects of the brick surface critically determined process yield in slicing Si wafers. </LI> </UL> </P>