• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.143-146
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• 2005

In modern automotive control modules, mechanical failures of surface mounted electronic components such as microprocessors, crystals, capacitors, transformers, inductors, and ball grid array packages, etc., are mai or roadblocks to design cycle time and product reliability. This paper presents a general methodology of failure analysis and fatigue prediction of these electronic components under automotive vibration environments. Mechanical performance of these packages is studied through finite element modeling approach fur given vibration environments in automotive application. Using the results of vibration simulation, fatigue lift is predicted based on cumulative damage analysis and material durability information. Detailed model of solder/lead joints is built to correlate the system level model and obtain solder strains/stresses. The primary focus in this paper is on surface-mount interconnect fatigue failures and the critical component selected for this analysis is 80 pin plastic leaded microprocessor.

• Advances in aircraft and spacecraft science
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• 제5권2호
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• pp.239-249
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• 2018

Physical tests are performed at various stages of the development cycle of a product, from prototype validation to product qualification. Although costly, there are growing demands for qualification tests like endurance vibration testing to be more representative of the real world. At the same time there are growing demands to assess the durability of these items based on FEA simulation. In this paper, we will explain how to set up a CAE-based test and how to correlate the results with some physical measurements. Specific assumptions will be explained and some advantages of using virtual tests will be highlighted such as the reduction of the number of prototypes needed, investigations on failures, evaluation of the level of reliability via sensitivity analysis, evaluation of the margins are at the end of a successful test. This presentation will therefore focus on explaining and showing how virtual tests can enrich the exploitation of physical tests.

• 한국신뢰성학회:학술대회논문집
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• 한국신뢰성학회 2005년도 학술발표대회 논문집
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• pp.357-376
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• 2005

• 한국신뢰성학회지:신뢰성응용연구
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• 제16권2호
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• pp.125-133
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• 2016

Purpose: The purpose of this study is to evaluate durability of platform safety step system in railway. Method: We performed finite element analysis & durability analysis of platform safety step system with VPD (Virtual Product Development) techniques and examined the durability standard & qualification life through the rig test during no failure test time in reliability qualification test. We continued to test 1 million cycles in KRS (Korea Railway Standard) for system's robust design performance. Result: FEM analysis results are 14.9MPa & 14.7MPa of pin-joint, pivot and durability analysis result is above 1 million cycles. we calculated theoretically no failure test time 855,000 cycles and through the 1 million cycles durability rig test in KRS standard we confirmed product quality. Conclusion: This platform safety step system was designed very safe in terms of a mechanical strength & durability.

• International Journal of Computer Science & Network Security
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• 제23권2호
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• pp.152-163
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• 2023

This research aimed at investigating Islamic Studies teachers' attitudes towards utilizing virtual learning environment in distance teaching among primary stage pupils. It also aimed at determining the statistical differences among variables due to sex, educational qualification, number of years of experience, and training sessions. This research adopted the descriptive approach. The sample consisted of male and female primary teachers of Islamic Studies (N=250) in governmental schools in Taif. The questionnaire was used as a main research tool. It included (20) items. Results showed that Islamic Studies teachers' attitudes towards utilizing virtual learning environment in distance teaching among primary stage pupils were ranked to a medium degree. There was a statistically significant difference among primary Islamic Studies teachers' attitudes due to sex variable. It was recommended to adopt more training sessions and seminars for adopting the idea of utilizing virtual learning environments among Islamic Studies teachers at boys' and girls' school in Mecca through emphasizing its significance and benefits in Teaching.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2007년도 춘계학술대회 논문집
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• pp.531-532
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• 2007

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계 학술대회논문집(수송기계편)
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• pp.204-207
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• 2005

A reliable and practical finite element modeling technique to predict the lifetime of automotive electronics is important for engineers in reliability. In reliability evaluation on the automotive electronics, most studies rarely used FE model verification process. The material properties and boundary conditions are very important factors in this process to assure the reliability of the automotive electronics. This study aims to develop a better and more accurate FE model in order to predict fatigue life of the automotive electronics using Virtual Qualification lifetime assessment techniques. After conducting the modal analysis by the experiments to grasp a system characteristic, this paper presents material properties and boundary conditions that is obtained by the comparisons of FEA simulation results using DOE technique and the experiment results.

• 한국산업융합학회 논문집
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• 제25권4_2호
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• pp.663-671
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• 2022

Practice through virtual reality can increase the educational effect regardless of time and place, and it is an educational method that is being pursued even in the situation of COVID-19. On the other hand, for VR-based education, related technology development and content development must be made, and experiential methods (flipped learning, blended learning, hybrid learning) must be provided in the educational process. The development scenario was developed with the contents of drone qualification test (ultra-light unmanned multicopter) and drone practice and the possibility of non-face-to-face self-directed learning (flipped learning, blended learning, hybrid learning). It is expected that the quality of vocational education related to drones and the effect of high education will be improved through the contents, and it is thought that it will be possible to suggest a direction for the development of various vocational education contents in non-face-to-face education.

• 한국의류산업학회지
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• 제23권4호
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• pp.504-514
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• 2021

This study attempted to extract and structure the job skills required for 3D designers, which have been recently introduced to the fashion industry. The study aimed to materialize and objectify the 3D designer's job, using a focus group interview for the survey. The 3D designer has the TD task of making 3D virtual samples using the pattern files developed in Pattern CAD. Graphic design and fabric digitization are also major tasks for the 3D designer. CLO is mainly used for 3D virtual sample production, and PixPlant, Substance, Photoshop, Cinema 4D, Daz studio, and 3ds MAX are used for image and avatar editing. As per the job skills required for 3D design work, basic knowledge about patterns and sewing, skill in 3D virtual clothing technology, ability to use various software, and English skills were considered important, in that order. In particular, the need for knowledge about patterns and sewing became more important than the skill in 3D virtual clothing technology itself. To train 3D designers, it was found that not only 3D virtual clothing software, but also education on patterns and clothing construction, CAD developer's curriculum certification system, and 3D designer qualification management were required. In addition, 3D designers are recognized as an essential job in fashion vendors, and the demand for domestic brands is increasing. The biggest limitation of the 3D virtual clothing system is the perfection of the digital fabric. Also, technical improvement is needed.

• 한국산학기술학회논문지
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• 제13권9호
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• pp.3889-3894
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• 2012

국내 여객을 취급하는 철도역사의 승강장은 간선철도노선의 저상승강장(500mm)과 광역전철구간의 고상승강장(1135mm)으로 구분 운용되고 있다. 저상승강장 전용 중 고속 열차가 수도권 전철구간(고상승강장)과 본선구간(저상승강장)에서 혼용 운영될 경우를 대비하고 안전운전 및 승객편의를 함께 고려하기 위해 저상 고상 승강장 겸용 승강시스템의 개발은 필수적이다. 한편 현재 개발 중인 시스템(스텝)에 대한 국내의 내구성 및 신뢰성 시험 기준은 존재하지 않는다. 따라서 본 연구에서는 저상/고상 승강장 겸용 텔레스코픽 슬라이드방식 승강문 스텝의 개발을 위한 연구 일환으로서, VPD관점에서 내구성 해석을 수행하고 신뢰성 보증시험에 준한 무고장 시험시간동안 실물 리그시험을 통하여 이의 내구성 기준 및 보증수명을 검토하였다.