• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.2
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• pp.149-155
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• 2013

In these days, Entity-Relationship Model is the most popular modeling tool for designing databases, and XML is a de facto standard language for representing and exchanging data. But, because of many commercial products supporting Entity-Relationship Model use their's own representation formats, and thus it gives rise to difficulties the inter-operability between these products. In this paper, we propose an ERX, a generation tool of XML Schema from Entity-Relationship Model. ERX receives an Entity-Relationship Diagram as an input, transforms it based on transformation rules, and generates a XML Schema Definition as an output. Transformation rules contain entity set, relationship set, mapping cardinalities, and generalization.

• The Journal of Korean Association of Computer Education
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• v.14 no.1
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• pp.123-135
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• 2011

In this paper, we propose a system that starts with the searching result of user's query and continuously offers new keywords related to the query. The primary purpose of the proposed system is to help users find information that the users cannot explain clearly. The proposed system obtains useful information by connecting different information sources, represents the information under an integrated schema, and offers a cross searching environment. In addition, it presents a visualized diagram that shows relations between keywords so that users can easily find the desired information. Therefore users can find information easily in an envirionment that is not limited to a certain site.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1791-1797
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• 2010

The Urban Transit Standardization Program has been supported by the Ministry of Land, Transport and Maritime Affairs. The Program consists of dozen or more projects and thus is quite complex, which implies that the program success heavily depends upon the effective management of various artifacts during the development. Particularly, in the complex systems development, developing and managing requirements is very important throughout the whole system life cycle. The requirements can be the basis of the design changes to be made later as well as the test and evaluation to be performed in the subsequent stages of the systems development. As such, the derivation of the system's requirement based on the needs from the customers, or stakeholder in a broad sense must be done properly. In particular, notice that the system is being developed but the system requirements are not fully available for some reasons. To complement this situation is the purpose of the study. To derive proper requirements effectively in the process of development, this paper proposes to draw up scenario using the output of the system under development and to utilize the use case diagrams and operational scenarios.

• Journal of Power System Engineering
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• v.12 no.4
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• pp.57-63
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• 2008

The last stage blade of the low pressure steam turbine remarkably affects turbine plant performance and availability Turbine manufacturers are continuously developing the low pressure last stage blades using the latest technology in order to achieve higher reliability and improved efficiency. They tend to lengthen the last stage blade and apply shrouds at the blades to enhance turbine efficiency. The long blades increase the blade tip circumferential speed and water droplet erosion at shroud is anticipated. Parts of integral shrouds of the last stage 40 inch blades were cracked and liberated recently in a combined cycle power plant. In order to analyze the root cause of the last stage blades shroud cracks, we investigated operational history, heat balance diagram, damaged blades shape, fractured surface of damaged blades, microstructure examination and design data, etc. Root causes were analyzed as the improper material and design of the blade. Notches induced by erosion and blade shroud were failed eventually by high cycle fatigue. This paper describes the root cause analysis and countermeasures for the steam turbine last stage blade shroud cracks of the combined cycle power plant.

• Transactions of Materials Processing
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• v.20 no.7
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• pp.512-517
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• 2011

TRB(Tailor Rolled Blank) is an emerging manufacturing technology by which engineers are able to change blank thickness continuously within a sheet metal. TRB door inner panels with required larger thicknesses can be used to support localized high loads. In this study, the aluminum alloy 5J32 TRB sheet is used for a door inner panel application. The TRB material properties were varied by using three heat treatment conditions. In order to predict the failure of the aluminum TRB during simulation, the forming limit diagram, which is used in sheet metal forming analysis to determine the criterion for failure, was investigated. Full-field photogrammetric measurement of the TRB deformation was performed with an ARAMIS 3D system. A FE model of the door inner panel was created using Autoform software. The material properties obtained from the tensile tests were used in the numerical model to simulate the door inner of AA 5J32 for each heat treatment condition. After finite element analysis for the evaluation of formability, a prototype front door panel was manufactured using a hydraulic press.

• Journal of The Korean Astronomical Society
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• v.43 no.5
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• pp.141-152
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• 2010

UBV I CCD photometry is obtained for the open clusters NGC 4609 and Hogg 15 in Crux. For NGC 4609, CCD data are presented for the first time. From new photometry we derive the reddening, distance modulus and age of each cluster - NGC 4609 : E(B-V ) = $0.37{\pm}0.03$, $V_0-M_V=10.60{\pm}0.08$, log $\tau$= 7.7 $\pm$ 0.1; Hogg 15 : E(B - V ) = 1.13 $\pm$ 0.11, $V_0-M_V$ = 12.50 $\pm$ 0.15, log $\tau$ $\lesssim$ 6.6. The young age of Hogg 15 strongly implies that WR 47 is a member of the cluster. We also determine the mass function of these clusters and obtain a slope $\Gamma$ = -1.2 ($\pm$0.3) for NGC 4609 which is normal and a somewhat shallow slope (${\Gamma}=-0.95{\pm}0.5$) for Hogg 15.

• The Bulletin of The Korean Astronomical Society
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• v.35 no.2
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• pp.82.1-82.1
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• 2010

We have investigated the spatial configuration of stars within the tidal radius of metal poor globular cluster NGC 6626 in the bulge direction. Data were obtained in near-IR J,H,Ks bands with wide-field ($20'\times20'$) detector, WIRCam at CFHT. To trace the stellar density around target cluster, we sorted cluster's member stars by using a mask filtering algorithm and weighting the stars on the color-magnitude diagram. From the weighted surface density map, we found that the stellar spatial distributions within the tidal radius appear asymmetric and distorted features. Especially, we found that more prominent over-density features are extending toward the direction of Galactic plane rather than toward the directions of the Galactic center and its orbital motion. This orientation of the stellar density distribution can be interpreted with result of disk-shock effect of the Galaxy that the cluster had been experienced. Indeed, this over-density feature are well represented in the radial surface density profile for different angular sections. As one of the metal poor globular clusters with extended horizontal branch (EHB) in the bulge direction, NGC 6626 is kinematically decoupled from the normal clusters and known to have disk motion of peculiar motion. Thus, our result will be able to add further constraints to understand the origin of this cluster and the formation of bulge region in early universe.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.362-368
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• 2008

The purpose of this is providing employees who take charge of operation and maintenance at power plant with education contents that can be used for self-studying and on the job training through their computers. We developed the education contents for making actually application possible using this piping and instrument diagram(P&ID), operation and maintenance procedure, unit specification and material of 500MW thermal power plant those include unit equipment 3-dimension animation, character and narration performance considering making teaching plan, flexibility, extension, reuse, maintenance and focusing on user. Specially, we developed the flash type education contents about power plant operation based on the plant 3-dimension animation and the spot real picture concerned about new generation trend for power plant incoming employees actual knowledge. in addition, this contents apparently contributed to improve the level of employees technical power as distributed to employees.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.46.1-46.1
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• 2010

일반적으로 석출물의 석출은 핵생성(Nucleation)-성장(Growth)-조대화(Coarsening)의 단계를 거친다. 핵생성에 의해 생성된 개개의 핵들은 아직 열역학적으로 평형 상태가 아니다. 석출물의 부피 분율은 아직 상태도에서 예측할 수 있는 값까지 도달하지 못했다. 과포화된 기지에서 생성된 핵은 계속적으로 기지로부터 용질 원자를 공급받아 성장하게 된다. 석출물의 성장은 그 부피 분율이 상태도에서 예상되는 값에 도달할 때까지 계속된다. 시간에 따른 석출 분율 계산과 분산된 석출물들이 matrix내에서 어느 정도 용해도를 갖는다면, 보다 작은 크기의 입자들은 용해되어 보다 큰 입자로 석출(성장)하려는 경향이 있다. 이러한 현상의 구동력은 전체 시스템의 계면 에너지 감소에 의해 주어지며, 결국 하나의 큰 입자만이 존재하게 될 것이다. 본 연구에서는 석출분율을 계산하기 위해 상용프로그램인 Pandat을 통해 Mg-Al 2원계합금의 상태도 및 석출분율 계산을 위한 열역학 데이터를 계산하였다. 계산된 열역학 데이터는 C언어로 함수화 하여 입력하고 Excell을 통해 석출분율을 계산하였다. 계산된 석출분율과 실험값의 비교를 통해 fitting parameters를 대입하여 계산값 및 실험값의 오차율을 줄였다. 본 연구에서 계산된 석출분율은 미래의 석출상 크기 및 분포 등을 개발하는 기초데이터로 활용할 수 있을 것이다.

• Journal of the military operations research society of Korea
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• v.22 no.2
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• pp.166-181
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• 1996

Aircraft survivability is determined by the susceptibility and the vulnerability. The aircraft susceptibility and vulnerability depend upon the hardware and software factors. Each of the hardware and software factors consisted of the qualitative and quantitative attributes varies according to the time of the mission. In order to establish the mathermatical model to analyze and evaluate the aircraft survivability, qualitative factors have to be transformed into quantitative factors. Even if many researches in the area of dynamic concept analysis and conversion of qualitative factors into the quantitative factors has been insufficient. This research enhances these insufficient area by developing a reliable aircarft survivability analysis method. The major areas of this research are as follows. First, a method for the conversion of the qualitative factors into the quantitative factors is developed by combining the Fuzzy Set Theory concept and the Delphi Technique. Second, by using the stochastic network diagram for the dynamic survivability analysis, the aircraft survivability and the probability of kill are calculated from the state probability for the situation during mission. The advantage of the analysis technique developed in this research includes ease of use and flexibility. In other words, in any given aircraft's mission execution under any variable probability density function, the developed computer program is able to analyze and evaluate the aircraft survivability.