• 한국분말재료학회지
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• 제17권6호
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• pp.435-442
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• 2010

• 한국레이저가공학회:학술대회논문집
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• 한국레이저가공학회 1999년도 추계학술발표대회 논문개요집
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• pp.21-24
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• 1999

• Structural Engineering and Mechanics
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• 제7권6호
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• pp.589-599
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• 1999

This paper presents the development and applications of the software package JIFEX, a new finite element system which can be used for structural analysis and optimum design by the modern computer hardware and software technologies such as MS Windows95/NT and Pentium PC platforms. The complete system of JIFEX is programmed with $C/C^{++}$ language to make full use of advanced facilities of MS Windows95/NT. In the system, the finite element data pre-processing, based on the most popular CAD package AutoCAD (R13, R14), has been implemented, so that the finite element modeling could be integrated with geometric modeling of CAD. The system not only has interactive graphics facility for data post-processing, but also realizes the real-time computing visualization by means of the Dynamic Data Exchange (DDE) technique. Running on the Pentium computers, JIFEX can solve large-scale finite element analysis problems such as the ones with more than 60000 nodes in the finite element model.

• 소성∙가공
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• 제21권7호
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• pp.412-419
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• 2012

The ingot-breakdown scheme of a tower flange material (low-alloy steel) for offshore wind turbine was investigated using finite element (FE) simulations and experimental analyses. Based on compression test results of the low-alloy steel, a deformation processing map was generated using the superposition approach between the dynamic materials model (DMM) and Ziegler's instability criterion. The deformation processing map allowed determination of the optimum process conditions for the tower flange material. Within the FE simulations of the ingot breakdown process, the Cockcroft-Latham criterion, which considers ductile fracture, was used to predict the possibility of forming defects during the hot working process. In general, the critical value for the ductile fracture of steel is 0.74. During the ingot-breakdown under optimum process conditions, the actual tower flange forgings exhibited a relatively uniform shape without any forming defects.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.993-998
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• 2002

Ultra precision processing technology is the field which is seriously protected its technology by advanced nations. Because of this reason, this technology is very difficult to supply for domestic companies, also domestic companies are revealed the limit of technology development by itself. And then, those are depend on the technology development of advanced nation, domestic companies are not conquer application step with already developed parts. Of course, some cases of its research are succeed. those are included element technology, system technology and so on, for development of ultra precision processing system. To conquer technology holding ultra precision processing accuracy of no level, active research are needed. In this paper, stability of ultra precision cutting unit is analyzed, this unit is the kernel unit in ultra precision processing machine. According to alteration of shape and material about hinge, stability investigation is performed Through this stability investigation, trial and error is reduced in design and manufacture, at the same time, we are accumulated foundation data for un it control.

• 멤브레인
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• 제16권3호
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• pp.213-220
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• 2006

본 연구에서는 정밀여과 및 나노여과 분리막 시스템을 활용하여 염료 제조 시 필요한 탈염/정제/농축처리 기술을 개발하고 그에 따른 염료의 품질과 품질의 안정성을 향상시키며, 기존공정의 단수를 축소하여 생산성 향상, 인력저감 및 원재료의 비용을 감소하고자 하였다. 염료의 탈염/정제/농축처리시 염료의 다양한 농도에 적합한 분리막의 제조 및 가압식 막 element를 제작하고, 가압식 분리막 시스템에 맞는 막 모듈의 설계와 pilot-scale 시스템을 통해 염료의 처리수질 분석 및 운전인자를 도출하였다.

• 한국컴퓨터정보학회논문지
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• 제22권1호
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• pp.15-21
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• 2017

In this paper, we present a solution to the problems caused by using only text - based information as an index element when a commercialized missing person indexing system indexes missing persons registered in the database. The existing system could not be used for the missing persons inquiry because it could not formalize the image of the missing person registered together when registering the missing person. To solve these problems, we propose a method to extract the similarity of images by using OpenCV image processing and TensorFlow deep - running image processing, and to process images of missing persons to process them into meaningful information. In order to verify the indexing method used in this paper, we constructed a Web server that operates to provide the information that is most likely to be needed to users first, using the image provided in the non - regular environment of the same subject as the search element.

• 한국과학교육학회지
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• 제38권3호
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• pp.441-449
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• 2018

지식정보처리역량은 정보화 사회에서 필수적인 역량 중 하나이며 과학교육과도 매우 연관성이 깊은 역량이다. 본 연구에서는 과학탐구 과정에서 나타나는 지식정보처리역량의 요소를 찾아보고 중학생들이 이와 관련하여 어떠한 어려움을 겪는지 알아보고자 하였다. 이를 위해 문헌 연구를 바탕으로 다양한 지식정보처리역량의 정의에서 공통된 요소인 정보 수집, 정보 처리, 정보 활용의 세 가지 요소를 추출하였다. 또한 서울시에 위치한 중학교에서 동아리 활동을 하는 학생 8명의 탐구활동을 5개월간 참여관찰 하여 자료(면담 및 관찰 전사본, 탐구 보고서, 탐구일지, 현장 노트 등)를 수집하였고, 지속적 비교분석법을 이용하여 수집된 자료를 범주화하고, 지시정보처리역량 요소와 관련된 어려움을 추출하여 분석하였다. 연구 결과 정보 수집 요소는 탐구를 진행하는 내내 관찰할 수 있었으며 정보 분석 요소는 가설설정 단계와 탐구 결과 분석 단계, 탐구 결과를 공유하는 단계에서 관찰할 수 있었다. 정보 활용 요소는 탐구 보고서 작성 및 공유를 위한 포스터 제작 등에서 확인할 수 있었다. 학생들이 겪은 어려움으로는 정보 수집에서는 정보 수집의 확실성, 체계적인 검색 전략, 정보의 신뢰성 등을 확보하지 못한 점에서 나타났다. 정보 분석에서 겪는 어려움은 분석 프로그램의 사용, 정보 변환, 연계 정보의 해석 등의 미숙함에서 나타났다. 정보 활용에서 겪는 어려움은 정보의 조직화, 효과적 표현 능력의 부족함에서 나타났다. 이 연구는 지식정보처리역량이 과학교육에서 어떠한 방식으로 자리 잡을 수 있는지 그 단초를 제공하였다는 점에 의의가 있다.

• 소성∙가공
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• 제21권7호
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• pp.447-452
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• 2012

This paper is concerned with forming of Al-Zn-Mg-Sc aluminum alloy bolts, focusing on the effects of heat treatment and age-hardening on the formability and ductile damage evolution. Both experimental and finite element studies were performed. From the experiments, it is observed that the heat treatment or the normalization of Al-Zn-Mg-Sc aluminum alloy increases its formability dramatically resulting in successful bolt forming, while the effects of age-hardening at room temperature on the stress-strain relationship and formability are not very critical. Deformation characteristics such as distribution of effective stress and strain, material flow, and ductile damage evolution during bolt forming are examined using a commercial finite element package, Deform-2D. It should be noted that the extrusion load predicted by the finite element method matches well the experiment results. The finite element predictions on the deformation characteristics support the experimental observations such as fracture of bolt head flange, material flow, and distribution of hardness.

• 소성∙가공
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• 제11권1호
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• pp.75-83
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• 2002

Recently, the hydroforming process is widely applied to the automotive industry and rapidly spreaded to other industries. In this paper, An implicit finite element formulation for simulating axisymmetric tube hydroforming processes is performed. In order to describe normal anisotropy of the tube, Hill's non-quadratic yield function is employed. The frictional contact between die and tube and the frictionless contact between tube and fluid are considered using the mesh-normal vectors computed from the finite element mesh of the tube. The complete set of the governing relations comprising equilibrium and interfacial equations is linearized for Newton-Raphson procedure. In order to verify the validity of the developed finite element formulation, the axisymmetric tube bulge test is simulated and the simulation results are compared with experimental measurements. In a simulation of stepped circular tube hydroforming processes, an optimal hydraulic pressure curve is pursued by considering simultaneously internal pressures and axial forces.