• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.301-301
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• 2003

In current study, Nanocomposites are reinforced with carbon nanofiber, carbon nanotube and SiC, etc. Since the nano reinforcements have the excellent mechanical, thermal and electrical properties compared with that of existing composites, it has lately attracted considerable attention in the various areas. Cu have been widely used as signal transmission materials for electrical electronic components owing to its high electrical conductivity. However, it's size have been limited to small ones due to its poor mechanical properties. Until now, strengthening of the copper alloy was obtained either by the solid solution and precipitation hardening by adding alloy elements or the work hardening by deformation process. Adding the alloy elements lead to reduction of electrical conductivity. In this aspect, if carbon nanofiber is used as reinforcement which have outstanding mechanical strength and electric conductivity, it is possible to develope Cu matrix nanocomposite having almost no loss of electric conductivity. It is expected to be innovative in electric conducting material market. The unidirectional alignment of carbon nanofiber is the most challenging task developing the cooer matrix composites of high strength and electric conductivity. In this study, the unidirectional alignment of carbon nanofibers which is used reinforced material are controlled by drawing process and align mechanism as well as optimized drawing process parameter are verified via numerical analysis. The materials used in this study were pure copper and the nanofibers of 150nm in diameter and of 10∼20$\mu\textrm{m}$ in length. The materials have been tested and the tensile strength was 75MPa with the elongation of 44% for the copper. it is assumed that carbon nanofiber behave like porous elasto-plastic materials. Compaction test was conducted to obtain constitutive properties of carbon nanofiber Optimal parameter for drawing process was obtained by analytical and numerical analysis considering the various drawing angles, reduction areas, friction coefficient, etc. The lower drawing angles and lower reduction areas provides the less rupture of co tube is noticed during the drawing process and the better alignment of carbon nanofiber is obtained.

• Journal of Welding and Joining
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• 제26권3호
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• pp.45-50
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• 2008

SM45C steel rods being used generally for power transmission shafts and machine components was selected and welded by Butt-GMAW(Gas Metal Arc Welding) method. An estimation of fatigue life was studied by constructing S-N curve. Fatigue strength of base metal zone showed higher values than one of weld zone in low cycles between $10^4$ and $10^6$cycles. However, significant decrease in fatigue strength of base metal was found around $10^6$cycles, which were almost same as one of heat affected zone. This decrease was attributed that initial residual stress of the steel rods distributed by drawing process was diminished by continually applied load, and resulted in softening of base metal. The fatigue limit of the weld zone was highest in the boundary between deposited metal zone and heat affected zone, and followed by in the order of deposited metal zone, base metal zone, and heat affected zone. Based on these results, it is revealed that the stress for safety design of machine components using SM45C butt-welded steel rods must be selected within the region of the lowest fatigue limit of heat affected zone.

• 한국초등과학교육학회지:초등과학교육
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• 제34권1호
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• pp.46-57
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• 2015

The purpose of this study was to analyze the writing styles and features of science writing by using science notebook for elementary school science gifted. The subject of this study was 37 sixth grade elementary school science gifted in P city. The preliminary 1 hour instruction was conducted to explain the usage of science notebook. The summarized activity using science notebook was conducted for 20 minutes following 4 hour lesson. These activities were performed for 8 times. As the result of this study, in The content which is learned today (main learning content)' which is one of components of science note, the writing appears the most frequently in external expression types and features of scientific writing, followed by writing+drawing, drawing, cartoon, writing+cartoon, mind map, table. Science writing which uses inductive thinking appears the most frequently in internal expression types and features of scientific writing, followed by deductive thinking, creative thinking. Among the components of science note, 'thinking and feeling', 'question,' 'one's own thinking of question' which are the components of science note promote the reflective thinking of elementary school student gifted for science.

• 한국인터넷방송통신학회논문지
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• 제17권3호
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• pp.275-282
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• 2017

차세대 3차원 건축설계 기법으로 각광받고 있는 BIM(Building Information Modeling)기술을 기반으로 하는 건축 설계 프로그램 중 대표적인 프로그램으로 Revit 프로그램이 있다. Revit은 정보 입력 측면을 강화시켜 설계 단계에서부터 구성요소의 정보 패밀리라는 오브젝트로 만들어 알기 쉽게 구성 요소를 파악 할 수 있는 프로그램이나, 이 프로그램에서 추출된 도면 출력파일들을 쉽게 비교하는 프로그램이 전무하고, 이로 인하여 협업 시에 수정된 동일 도면들에 대한 변경 내용의 분석이나 도면 정보의 손쉬운 공유가 어려운 점이 문제로 대두되고 있다. 이에 본 논문에서는 Revit을 통한 출력 도면 파일들의 병렬적 협력 작업이 효율적으로 이루어지도록 하기 위하여 동일 도면에 출력 파일들에 대한 버전 관리 시스템의 제안 및 구현을 하였으며 다른 버전 도면 파일들 간의 수정 부분을 검출하기 위한 개선된 KMP알고리듬을 제안한다.

• 한국전산구조공학회논문집
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• 제34권1호
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• pp.19-24
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• 2021

본 논문에서는 배관의 ISO 도면 교환파일을 이용하여 AR/VR모델을 실시간으로 생성하는 방법을 소개한다. 도면 교환 파일 중에서 산업 표준으로 활용되는 IDF 파일을 분석했으며, 속성 정보의 추출과 함께 형상을 파라메트릭한 방법으로 정의하는 방법을 사용하였다. 이 방법을 통해서 파일 크기가 작은 도면 교환 파일을 사용함으로써 원거리 데이터 교환이 용이하면서도 형상과 속성을 모두 전달할 수 있는 효과를 가질 수가 있다. 이 과정에서 본 논문에서는 배관과 컴포넌트의 형상을 템플릿 형태로 정의해 놓았으며, 이를 통해 배관의 도면 교환 파일로부터 실시간으로 배관 형상을 생성함과 동시에 설계 정보와 함께 AR/VR모델로 가시화가 됨을 검증하였다.

• 한국전자거래학회지
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• 제1권2호
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• pp.77-92
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• 1996

In recent years, the manufacturing industry begins to demand the PDM which integarates design and manufacturing information concurrently to reduce the time-to-market of new products. However, current commercialized PDM tools have drawbacks in representing by relational data modeling a variety of data types such as CAD files, images, audio, long text, etc. For this reason, object-oriented approaches are suggested as an alternative. In this paper, using one of object-oriented approaches, Rumbaugh's OMT(Object-Modeling Technique), we propose a data model of drawing information management systems essential for PDM. The scope of the model is limited to the information management for drawings, parts, and product structures. Static, dynamic and functional models are suggested in detail. In the models, the drawing status is classified into on-progress, approved, disposed, and released. Also, parts are classified into products, assemblies, and components.

• 한국건설관리학회논문집
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• 제1권4호
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• pp.98-105
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• 2000

The drawing information takes the most essential part of construction information. The management of construction information through drawing information facilitates input, output and search process, thus helping maximize the usage of construction information by effectively sharing construction experience and drawing information. This paper shows how construction information can effectively used to increase the productivity of the construction process as a whole. Construction information was extracted and classified by the elements of building which are the basic and very end components of building, to accumulate information of each construction phase. Based on the result, the Element Breakdown Structure(EBS) was developed for the practical usage of construction information integration.

• 한국해양공학회지
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• 제14권4호
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• pp.86-91
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• 2000

Numerical simulation of sheet metal forming for panels as other components has wide acceptance in the automotive industry. Therefore this paper was focused in the drawability factors (which are friction coefficient , radius of die and punch ) on the square cup deep drawing by the explicit finite elements code $PAM-STAMP^{TM}$. The computed results are compared with the experimental results to show the validity of the analysis. In order to compare the simulation results with the experiment results and predict the effect of drawability factors, the relationships between punch load punch stroke, and the relationships between thickness strain and distance are used. According to this study, the results of simulation by using $PAM-STAMP^{TM}$ will give engineers good information to access the drawability of square drawing.

• 대한기계학회논문집A
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• 제32권6호
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• pp.474-480
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• 2008

Recently, rods having irregular sections more complex than a rectangle or ellipse are necessary to produce mechanical parts. The cold shaped drawing process is used to obtain shaped drawn products with high levels of dimensional accuracy and quality. A cross roller guide, considered in this study, is one of the parts produced by shaped drawing process. A cross roller guide has a linear bearing system that rolls along a guide way. A cross roller guide is one of the most important components in terms of equipment because the quality of the product influences the precision linear motion. Therefore, the final dimensional accuracy of the linear rail in the shaped drawing is very important. The objective of this study is to find the optimized die angles to improve the dimensional accuracy and straightness of the final shaped drawn product. In order to achieve the aim of this study, design of experiment, FE-simulation, and the Taguchi method were used. Based on the analytical results, shaped drawing experiment has been performed to verify the result.

• 한국CDE학회논문집
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• 제5권3호
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• pp.255-262
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• 2000

A computer-aided process planning (CAPP) system for rotationally symmetric deep drawing products has been developed. The application for non-axisymmetric components, however, has not been reported yet. Therefore, this study investigates process sequence design in deep drawing process and constructs an expert system of process planning for non-axisymmetric motor frame products with elliptical shape. The system developed consists of four modules. The first one is recognition of shape module to recognize the products. The second one is a 3-D modeling module to calculate surface area for non-axisymmetric products. The third one is a blank design module that creates an oval-shaped blank with the identical surface area. The forth one is a process planning module based on production rules that play the best important role in an expert system for manufacturing. The production rules are generated and upgraded by interviewing with field engineers. The constructed system using AutoLISP language under the AutoCAD environment is baled on the knowledge base system which is involved a lot of expert's technology. Results of this system will be provide effective aids to the designer and engineer in this field.