• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.346.1-346.1
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• 2014

Porous nano crystalline $TiO_2$ is currently used as a working electrode in a dye-sensitized solar cell (DSSC). The conventional working electrode is comprised of absorption layer (particle size:~20 nm) and scattering layer (particle size:~300 nm). We inserted window layer with 10 nm particle size in order to increase transmittance and specific surface area of $TiO_2$. The electrochemical impedance spectroscope analysis was conducted to analysis characterization of the electronic behavior. The Bode phase plot and Nyquist plot were interpreted to confirm the internal resistance caused by the insertion of window layer and carrier lifetime. The photocurrent that occurred in working electrode, which is caused by rise in specific surface area, increased. Accordingly, it was found that insertion of window layer in the working electrode lead to not only effectively transmitting the light, but also increasing of specific surface area. Therefore, it was concluded that insertion of window layer contributes to high conversion efficiency of DSSCs.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.273.1-273.1
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• 2014

Graphene, a two dimensional plane structure of $sp^2$ bonding, has been promised for a new material in many scientific fields such as physics, chemistry, and so on due to the unique properties. Chemical vapor deposition (CVD) method using transitional metals as a catalyst can synthesize large scale graphene with high quality and transfer on other substrates. However, it is difficult to control the number of graphene layers. Therefore, it is important to manipulate the number of graphene layers. In this work, homogeneous solid solution of Cu and Ni was used to control the number of graphene layers. Each films with different thickness ratio of Cu and Ni were deposited on $SiO_2/Si$ substrate. After annealing, it was confirmed that the thickness ratio accords with the composition ratio by X-ray diffraction (XRD). The synthesized graphene from CVD was analyzed via raman spectroscopy, UV-vis spectroscopy, and 4-point probe to evaluate the properties. Therefore, the number of graphene layers at the same growth condition was controlled, and the correlation between mole fraction of Ni and the number of graphene layers was investigated.

• Bulletin of the Korean Chemical Society
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• 제32권3호
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• pp.880-884
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• 2011

ZnO nanorods were grown by hydrothermal method. Two kinds of seed layers, Au film and island seed layers were prepared to investigate the effect of seed layer on ZnO nanorods. The ZnO nanorod on Au island seed layer has more unifom diameter and higher density compared to that of ZnO nanorod on Au film seed layer. The ZnO nanorods on Au island seed layer were annealed at various temperatures ranging from 300 to $850^{\circ}C$. The pinholes at the surface of the ZnO nanorods is formed as the annealing temperature is increased. It is noted that the pyramid structure on the surface of ZnO nanorod is observed at $850^{\circ}C$. The intensity of ZnO (002) diffraction peak in X-ray diffraction pattern and intensity of near band edge emission (NBE) peak in photoluminescence (PL) are increased as the ZnO nanorods were annealed at the temperature of $300^{\circ}C$.

• Structural Engineering and Mechanics
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• 제48권3호
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• pp.291-308
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• 2013

Structural health monitoring is crucial to maintain the structural performance safely. Moreover, the Kullback-Leibler divergence (KLD) is applied usually to asset the similarity between different probability density functions in the pattern recognition. In this study, the KLD is employed to detect the damage. However the asymmetry of the KLD is a shortcoming for the damage detection, to overcoming this shortcoming, two other divergences and one statistic distribution are proposed. Then the damage identification by the KLD and its three descriptions from the symmetric point of view is investigated. In order to improve the reliability and accuracy of the four divergences, the gapped smoothing method (GSM) is adopted. On the basis of the damage index approach, the new damage index (DI) for detect damage more accurately based on the four divergences is developed. In the last, the grey relational coefficient and hypothesis test (GRCHT) is utilized to obtain the more precise damage identification results. Finally, a clear remarkable improvement can be observed. To demonstrate the feasibility and accuracy of the proposed method, examples of an isotropic beam with different damage scenarios are employed so as to check the present approaches numerically. The final results show that the developed approach successfully located the damaged region in all cases effect and accurately.

• 한국정밀공학회지
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• 제22권9호
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• pp.93-98
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• 2005

The purposes of this paper are the review and derivation of design characteristics for the new construction of the practical flexible manufacturing system. The basic ideas to analyze the manufacturing system which is the automatically operated are dependant on the various manufacturing procedures in factory. The practical flexible manufacturing systems have various mechanical subsystems appropriated fur the final manufacturing products. Therefore the systems have the various kinds of hardwares as well as softwares. We study the software for the practical flexible manufacturing system designed and developed in the Halla University with the related company. Specially the design concepts and using specifications of all subsystems which are composed of mechanical and electronic movements of the product are analyzed and introduced in this dissertation.

• Journal of Ship and Ocean Technology
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• 제8권4호
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• pp.45-55
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• 2004

How to achieve engineering collaboration among diverse engineering activities is one of the key topics in manufacturing fields nowadays. The infrastructure for collaborative engineering is essential, and it can be realized by information technologies and intelligent engineering applications in digital environments. Digital Manufacturing is a technology to facilitate effective product developments and agile productions by computer models representing the physical and logical schema and the behavior of real manufacturing systems including products, processes and factories. A digital factory as a well-designed and integrated digital environment is incorporated in it. In this paper, digital manufacturing is recommended as a good strategy for collaborative engineering, especially in product developments and productions. By business process analysis and some case studies, we suggested sophisticated digital models are very useful to concurrent and collaborative engineering. It is expected that digital manufacturing is a very good strategy for achieving dramatic time and cost savings in many engineering activities of many manufacturing industries, including machinery, automotive and shipbuilding.

• 한국산업정보학회논문지
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• 제12권5호
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• pp.201-210
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• 2007

본 연구는 우리나라 기업들이 제조경쟁력을 향상시키기 위해서 도입하고 있는 생산정보화의 현황을 파악하고, 생산계획 및 통제를 위해서 정보 기술이 중소기업과 대기업에 있어서 어떤 차이가 있는지를 실증적으로 분석하고자 한다. 이를 달성하기 위해서 최근에 조사된 105개의 우리나라 제조기업에 대한 자료를 이용하여 생산정보화 수준과 기업의 규모에 따른 차이 등에 대해서 통계적으로 검증하였으며, 대기업과 중소기업에 있어서 많은 차이가 있음을 알 수 있었다.

• 한국정보시스템학회지:정보시스템연구
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• 제26권4호
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• pp.63-85
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• 2017

Purpose Recently, much attention in building smart factory has dramatically increased with an emergence of the Industry 4.0. As we noted a connectivity gap between main concerns of MIS and the automated manufacturing systems such as POP and MES, it is recommended that CPS (Cyber-Physical System) can be an important building block for the smart factory and enrich the depth of MIS knowledge. Therefore, first, this study attempted to identify the connectivity gap between the traditional field of MIS (ERP, SCM, CRM, etc.) and the automated manufacturing systems, and then recommended CPS as a technical bridge to fill the gap. Secondly, we studied concepts and research trend of CPS that is believed to be a virtual mechanism to manage manufacturing systems in an integrated manner. Finally, we suggested research and educational opportunities in MIS based on the CPS perspectives. Design/methodology/approach Since this paper introduced relatively new idea of CPS originally discussed in the field of engineering, traditional MIS research method such as survey and experiment may not fit well. Therefore this research collected technical cases through literature survey in engineering fields, video clips from Youtube, and field references from various ICT Exhibitions and Conventions. Then we analyzed and reorganized them to highlight the necessity of CPS and draw some insight to share with MIS academia. Findings This paper introduced CPS to bridge the connectivity gap between the traditional MIS and automated manufacturing system (smart factory), a concern far away from the MIS academia. Further, this paper suggested future research subjects of MIS such as developing software to share big production data and systems to support manufacturing decisions, and innovating MIS curricula including smart and intelligent manufacturing technology within the context of traditional enterprise systems.

• 대한산업공학회지
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• 제24권1호
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• pp.61-76
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• 1998

Tooling is now considered as a major limiting resource for highly automated manufacturing systems to be operated unattendedly. In this paper, various issues in tooling are introduced and discussed. The importance of appropriate selection of tooling strategies is discussed and simulation experiments are performed to see how the tooling strategies affect the system performance in automated manufacturing systems. This paper also presents a tool management system developed in Korea Institute of Machinery and Materials.

• 한국정밀공학회지
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• 제26권11호
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• pp.20-28
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• 2009