Localized remeshing techniques for three-dimensional metal forming simulations with linear tetrahedral elements

Son, Il-Heon,Im, Yong-Taek John Wiley Sons, Ltd. 2006 International Journal for Numerical Methods in Eng Vol.67 No.5

<P>The localized remeshing technique for three-dimensional metal forming simulations is proposed based on a mixed finite element formulation with linear tetrahedral elements in the present study. The numerical algorithm to generate linear tetrahedral elements is developed for finite element analyses using the advancing front technique with local optimization method which keeps the advancing fronts smooth. The surface mesh generation using mesh manipulations of the boundary elements of the old mesh system was made to improve mesh quality of the boundary surface elements, resulting in reduction of volume change in forming simulations. The mesh quality generated was compared with that obtained from the commercial CAD package for the complex geometry like lumbar. The simulation results of backward extrusion and bevel gear and spider forgings indicate that the currently developed simulation technique with the localized remeshing can be used effectively to simulate the three-dimensional forming processes with a reduced computation time. Copyright © 2006 John Wiley & Sons, Ltd.</P>

Shape Evolution of Pinholes in Bloom with Multi-Scale Finite Element Technique

Son, Il Heon,Lee, Kyung Hoon Trans Tech Publications, Ltd. 2012 Advanced materials research Vol.445 No.-

<P>This study investigates the shape evolution of the pinholes on the bloom surfaces, which are originated from the continuous casting process, during multi-pass hot bar rolling. It is important to track the shape evolution of the pinholes since they can be formed as the sharp surface cracks after hot bar rolling and can initiate the surface bursts in the cold forging process. It is very hard to track the deformation behavior of the pinholes with detection tools during hot rolling, so the numerical simulations can be properly utilized. In general, the size of the pinholes in the bloom surface is order of micrometer although the bloom size is order of millimeter. This size discrepancy between them makes it difficult to discretize the domain including the pinholes for the finite element (FE) simulations. To overcome this limitation of the conventional FE simulation, multi-scale technique coupling the macro and micro models was developed in current study. This technique was implemented into the commercial simulation code, DEFORM-3D. The developed multi-scale simulation technique was capable of simulating the shape evolution of the pinholes through multi-pass hot bar rolling successfully. It is concluded that aspect ratio of the initial pinhole should be larger than 2.0 approximately to prevent it folded.</P>

Finite element investigation of equal channel angular extrusion with back pressure

Son, Il-Heon,Lee, Jeong-Ho,Im, Yong-Taek Elsevier 2006 Journal of materials processing technology Vol.171 No.3

<P><B>Abstract</B></P><P>The back pressure in equal channel angular extrusion (ECAE) can produce more uniform and increased strain level into the workpiece, consequently obtaining the improved material property of the workpiece. It also has advantages in fabricating the materials without forming defects by giving the compressive pressure to the material surfaces. This study numerically investigates the effect of back pressure on material behavior and strain distribution of the commercially available pure titanium (CP-Ti) specimen. The back pressure effect in multi-pass ECAE process was also examined. Three types of the die tooling termed as Type-I, Type-II and Type-III to apply back pressure were examined under the plane-strain and non-isothermal conditions. From the simulation results, it was found out that the back pressure applied to the ECAE greatly increased the strain level accumulated without reducing the uniformity of the strain distribution.</P>

이중몰입의 영향에 대한 권위주의성격과 "그들과 우리" 태도의 조절효과

손헌일 ( Heon Il Son ),윤영삼 ( Yeong Sam Yun ) 한국인적자원관리학회 2014 인적자원관리연구 Vol.21 No.1

최근 노사관계에서 중요한 현상으로 제기되는 이중몰입에 관해서는 크게 영향, 원인, 방법론적 이슈 등 많은 연구들이 수행되어 왔다. 이중몰입의 영향이 다양하다는 것은 기존연구에서 알려졌으나, 조절효과에 대해서는 별로 연구되지 않았다. 또한 이중몰입에 대한 설명력을 제고하는데 필요한 것으로서, 개인의 특성을 고려한 연구가 거의 없다. 이러한 문제의식에서 본 연구는 조합원의 중요한 성격과 태도인 권위주의성격과 그들과 우리태도의 조절효과를 살펴보고자 하였다. 이중몰입관련 조절효과에 관한 기존연구의 결과가 별로 없다는 점에서 본 연구는 탐색적 연구(exploratory study)이다. 이중몰입이 노조관련행동지향성에 미치는 영향을 권위주의성격과 그들과 우리태도가 조절하는가를 보기 위하여 관련 문헌들을 검토하여 개념과 연구동향을 정리하는 개념적 연구를 바탕으로 경험적 연구로서 설문조사를 통한 실증연구를 실시하였다. 실증연구로서, 부산지역의 민주노총 조합원 425부를 대상으로 연구가설을 검증하였다. 실증연구의 결과로서, 이중몰입이 높을수록 노조관련행동지향성이 높게 나타난 가운데, 이중몰입이 노조관련행동지향성에 미치는 영향에 대해 권위주의성격은 부(-)적으로 조절하고 그들과 우리태도는 정(+)적으로 조절하는 것으로 나타났다. 이러한 결과의 시사점을 들자면, 첫째, 개인특성의 조절효과를 본 연구가 탐색적으로 실증하였다는 점에서 향후 이에 대한 이론적 설명작업이 수행되어야 하며, 더 많은 개인특성의 조절효과에 대한 연구가 필요함을 시사하고 있다. 둘째, 권위주의성격과 관련하여 사용자의 입장에서는 높은 조합원이 바람직하고 노조의 입장에서는 그 반대임을 시사하므로, 채용과 민주관련 운영ㆍ교육ㆍ기회제공을 관리할 필요가 있다. 그리고 그들과 우리태도와 관련하여 사용자의 입장에서는 낮은 조합원이 바람직함을 시사하며 노조의 입장에서는 그 반대임을 시사하므로 회사나 노조에서의 초기사회화, 교육 및 경험에 의한 지각에 대한 관리가 필요하다. The purpose of this study is to examine the moderating effect of authoritarian personality and them-and-us attitude on the effect of dual commitment. Despite the progress of dual commitment studies, the effect of dual commitment relevant to industrial relations and the moderating effect in relation with dual commitment were not studied. This study considered the limitation of previous study and the help to the union and the company. This study built a exploratory model that there is causal relationship of dual commitment to union-related behavioral orientation and the moderating effect of authoritarian personality and them-and-us attitude on the effect of dual commitment. To test hypotheses empirically, the data was collected from 425 union members in Busan. The study showed following results. 1) Dual commitment had the positive effect on the union-related behavioral orientation significantly. 2) Trade union member``s authoritarian personality played the role as the negative moderating variable in relation with the effect of dual commitment on the union-related behavioral orientation. 3) Trade union member`s them-and-us attitude played the role as the positive moderating variable in relation with the effect of dual commitment on the union-related behavioral orientation. The implication of these results to the union and the company, the limitation of this study and the direction of future study were suggested.

이중몰입의 노조관련행동지향성에 대한 영향

손헌일 ( Heon Il Son ),윤영삼 ( Yeong Sam Yun ) 한국인적자원관리학회 2011 인적자원관리연구 Vol.18 No.1

본 연구는 이중몰입이 조합원의 노조관련행동지향성에 미치는 영향에 관한 탐색적 연구로서 이중몰입에 대한 노사 각각의 전략적 시사점을 제시하기 위하여 연구하였다. 이러한 연구목적을 달성하기 위하여 회사몰입, 노조몰입, 이중몰입, 노조관련행동지향성과 관련된 문헌연구와 경험적 연구로서 실증연구를 진행하였다. 실증연구에서는 부산지역 민주노총 조합원을 대상으로 한 설문지 207부를 분석에 사용하였다. 실증연구의 결과 이중몰입이 높은 조합원이 낮은 조합원보다 참가행동지향성, 파업성향, 투쟁성이 높은 것으로 나타났다. 그러나 이중몰입이 높은 조합원과 노조몰입만 높은 조합원의 노사관계행동지향성에는 차이가 없는 것으로 나타났다. 또한 이중몰입이 노조몰입과 회사몰입의 부수적인 현상이 아니라 독특한 개념임을 볼 수 있었다. 본 연구결과를 토대로 이중몰입이라는 현상에 대하여 노조와 회사는 각각 노조몰입과 회사몰입을 높이기 위한 노력을 기울여야 한다는 전략적 시사점을 제공할 수 있었다. The purpose of this study is to examine the effect of dual commitment on union member`s union-related orientation. This study focuses on giving the suggestion to union and the company. To test hypotheses empirically, questionnaire data from 207 union members in Busan are analysed. Results of analyses are as follow. First, both the company and the union unit committed have higher activity intention level and militancy level than both the company and the union unit uncommitted. Second, activity intention level, strike propensity level and militancy level from the trade union are not different between both the company and the union unit committed. Results of this study provide suggestions to the company and trade union as follow. (1) The company will raise a company commitment level to reduce the industrial relations action intention level. (2) The trade union must try to raise a trade union commitment level to raise the industrial relations action intention level.

Dermoscopic-histopathologic correlation between pigmentation of basal cell carcinoma and tumor aggressiveness in Asian patients

( Jong Heon Park ),( Hyunwoo Park ),( Tae Woong Seul ),( Jae Yeong Jeong ),( Jung Jin Shin ),( Hwa Jung Ryu ),( Sang Wook Son ),( Il-hwan Kim ) 대한피부과학회 2022 대한피부과학회 학술발표대회집 Vol.74 No.1

민속 씨름과 일본 스모(相撲)의 유래 및 경기방식과 대회운영에 관한 비교 연구

송일훈 ( Il Hun Song ),이동헌 ( Dong Heon Lee ),손수범 ( Soo Beom Son ) 한국체육사학회 2006 체육사학회지 Vol.17 No.-

Development of Anti-thrombogenic Zwitterionic Polyurethane Additives for Implantable Medical Device Applications

Dong Heon Ga,Sung Bin Park,Tae Il Son,Dong Keun Han,Yoon Ki Joung 한국고분자학회 2016 한국고분자학회 학술대회 연구논문 초록집 Vol.41 No.2

A smartphone fluorescence imaging-based mobile biosensing system integrated with a passive fluidic control cartridge for minimal user intervention and high accuracy

Lee, Won-Il,Park, Younghyeon,Park, Jaemin,Shrivastava, Sajal,Son, Young-Min,Choi, Hak-Jong,Lee, Jaelin,Jeon, Byeungwoo,Lee, Heon,Lee, Nae-Eung The Royal Society of Chemistry 2019 Lab on a chip Vol.19 No.8

<P>A key challenge for realizing mobile device-based on-the-spot environmental biodetection is that a biosensor integrated with a fluid handling sensor cartridge must have acceptable accuracy comparable to that of conventional standard analytical methods. Furthermore, the user interface must be easy to operate, technologically plausible, and concise. Herein, we introduced an advanced smartphone imaging-based fluorescence microscope designed for Hg<SUP>2+</SUP> monitoring by utilizing a biosensor cartridge that reduced user intervention <I>via</I> time-sequenced passive fluid handling. The cartridge also employed a metal-nanostructured plastic substrate for complementing the fluorescence signal output; this helped the realization of high-accuracy detection, in which a ratiometric dual-wavelength detection method was applied. Using 30 samples of Hg<SUP>2+</SUP>-spiked wastewater, we showed that our device, which has a detection limit of ∼1 pM, can perform analytical assays accurately. The detection results from our method were in good linearity and agreement with those of conventional standard methods. We conclude that the integration of a simple-to-use biosensor cartridge, fluorescence signal-enhancing substrate, dual-wavelength detection, and quantitative image data processing on a smartphone has great potential to make any population accessible to small-molecule detection, which has been performed in centralized laboratories for environmental monitoring.</P>

Improved Chlorophyll-a Algorithm for the Satellite Ocean Color Data in the Northern Bering Sea and Southern Chukchi Sea

Lee, Sang Heon,Ryu, Jongseong,Park, Jung-woo,Lee, Dabin,Kwon, Jae-Il,Zhao, Jingping,Son, SeungHyun Korean Ocean Research & Development Institute and 2018 OCEAN SCIENCE JOURNAL Vol.53 No.3