시편 예열 온도가 FCW 용착금속의 확산성 수소량에 미치는 영향

김동윤,황인성,김동철,강문진,Kim, Dong Yoon,Hwang, In Sung,Kim, Dong Cheol,Kang, Moon Jin 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.2

Cold cracking of weldment is one of the most serious welding problems. A sufficient quantity of diffusible hydrogen, a residual stress, and a sensitive microstructure are the causes of cold cracking. Removal of any one of these factors can be used to prevent cold cracking. Application of flux cored arc welding process is increasing due to high productivity and easiness of welding. In addition, to prevent cold cracking in the HAZ or weldment, preheat temperature and interpass temperature have to be controlled. In this study, the effect of preheat temperature on the levels of diffusible hydrogen in the weld metal deposited using flux cored wire was examined. The levels of preheat temperature of base metal specimen were ambient temperature, 50, 100 and $150^{\circ}C$ respectively. The result showed that the increase of preheat temperature was a linear relationship with reduction of diffusible hydrogen content in weldment.

부분결합간섭계에 내장된 인공수정체 도수측정 공식들의 정확성 비교

김동윤,김명준,김재용,차흥원,Dong Yoon Kim,MD,Myoung Joon Kim,MD,PhD,Jae Yong Kim,MD,PhD,Hungwon Tchah,MD,PhD 대한안과학회 2009 대한안과학회지 Vol.50 No.4

Purpose: To evaluate the accuracy of various formulas installed in IOLMaster software which uses partial coherence interferometry for axial length measurement. Methods: This retrospective comparative study included 81 eyes of consecutive patients who had uneventful cataract surgery with implantation of Acrysof single piece (SA60AT) IOL. Axial length was measured with IOLMaster and IOL power was calculated using various formulas, including SRK II, SRK/T, Holladay 1, Haigis, and Hoffer Q. Subjects were stratified by axial length into Groups A (axial length < 23.50 mm), B (23.50 mm ≤ axial length < 25.00 mm), and C (axial length ≥ 25.00 mm). Target refractions of the five formulas were compared to the postoperative manifest refraction at 1 month. Results: The five formulas showed no difference in predicting postoperative refractive errors among all of the groups. Conclusions: Five formulas installed in IOLMaster software provided equivalent predictions of postoperative refractive error regardless of axial length. J Korean Ophthalmol Soc 2009;50(4):523-528

마이토마이신을 이용한 라섹 수술 후 지연성으로 발생한 비대 각막 반흔 2예

김동윤,김명준,윤삼영,신철진,김경훈,차흥원,Dong Yoon Kim,MD,Myoung Joon Kim,MD,PhD,Sam Young Yoon,MD,Chul Jin Shin,MD,Kyoung Hoon Kim,MD,Hungwon Tchah,MD,PhD 대한안과학회 2009 대한안과학회지 Vol.50 No.2

Purpose: To report late-onset hypertrophic corneal scars after laser epithelial keratomileusis (LASEK) with mitomycin C. Case summary: Case 1. A 34-year-old man who had undergone LASEK with mitomycin C 15 months prior was referred to our clinic because of corneal opacity of his right eye. After LASEK, there have been no abnormalities in either of his eyes. However, 11 monthsafter LASEK, he experienced decreased visual acuity in his right eye. The visual acuity was 0.03 in his right eye and 1.0 in his left eye. On slit lamp examination there was a whitish, hypertrophic scarin his right cornea. The lesion was located in the corneal center and the subepithelial space. Central corneal thickness was 828 μm. Case 2. A 23-year-old woman who had undergone LASEK with mitomycin C 14 months before was referred our clinic because of corneal opacity of her left eye. After LASEK, there had been no abnormalities in either of her eyes. However, 12 months after LASEK she experienced decreased visual acuity in her left eye. The visual acuity was 1.0 in her right eye and 0.2 in her left eye. On slit lamp examination there was a whitish, hypertrophic scar in her left cornea. Central corneal thickness was 794 μm. Conclusions: Manual debridement was performed to remove the hypertrophic scar in both cases. Case 1. After manual debridement, visual acuity of the right eye improved to 0.63. Case 2. After manual debridement, best-corrected visual acuity of the left eye was 0.63.

GMA용접에서 콘택트 팁 재질에 따른 용접특성 평가

김동윤,황인성,김동철,강문진,Kim, Dong Yoon,Hwang, In Sung,Kim, Dong Cheol,Kang, Moon Jin 대한용접접합학회 2014 대한용접·접합학회지 Vol.32 No.6

The contact tip for gas metal arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. If the contact tip is damaged, it is a cause of lowering the welding productivity due to removal of welding defects and replacement of contact tip. In case of the use of a contact tip for a long time the arc is unstable because the processed hole in the contact tip center is larger, and the variation of aiming position of the welding wire causes a seam tracking error. In this study, gas metal arc welding experiments using contact tip of three different materials were performed. The contact tips with Cu-P, Cu-Cr, and Cu-ODS were used at the experiments, and the welding characteristics by each contact tip were evaluated. After welding contact tip appearance, welding spatter adhesion amount of the nozzle, and weld bead appearance were evaluated. The welding current and welding voltage were measured to verify arc stability during arc welding.

플럭스 코어드 와이어에 따른 용접 중 콘택트 팁 내마모성 평가

김동윤,황인성,김동철,강문진,Kim, Dong-Yoon,Hwang, In-Sung,Kim, Dong-Cheol,Kang, Moon-Jin 대한용접접합학회 2013 대한용접·접합학회지 Vol.31 No.4

The contact tip for flux cored arc welding has important functions to transmit the welding current to the wire and to guide the wire to molten pool. A damaged contact tip causes a productivity reduction and a welding quality problem. In this study, the welding experiments for the wear resistance of contact tip regarding flux cored wire types were performed. With two fold type and a seamless type flux cored wires, the wear rates of contact tips were compared. In addition, the wear rate was checked according to the contact tip position.

원격 스캐너를 이용한 알루미늄 레이저 용접에 대한 생산 공정 최적화 설계

김동윤,박영환,Kim, Dong-Yoon,Park, Young-Whan 대한용접접합학회 2011 대한용접·접합학회지 Vol.29 No.6

In this study, we conducted laser welding by using remote scanner that is 5J32 aluminum alloy to observe the mechanical properties and optimize welding process parameters. As the control factors, laser incident angle, laser power and welding speed were set and as the result of weldablility, tensile shear tests were performed. ANOVA (Analysis of Variation) was also carried out to identify the influence of process variables on tensile shear strength. Strength estimation models were suggested using regression alnalysis and 2nd order polynomial model had the best estimation performance. In addition optimal welding condition was determined in terms with wedalility and productivity using objective function and fitness function. Final optimized welding condition was laser power was 4 kW, and welding speed was 4.6 m/min.

마을 만들기 연구의 정량적 접근에 관한 소고 - 마을 만들기 사업규모와 성과의 관계를 중심으로 -

김동윤,김선직,강래천,Kim, Dong-Yoon,Kim, Sun-Jick,Kang, Rae-Cheon 한국디지털건축·인테리어학회 2011 한국디지털건축인테리어학회 논문집 Vol.11 No.2

Skeptical responses to urban design based on the Physical Planning theory assuming the existence of social agreement and the absolute authorities of planners bring about alternatives such as Participatory Planning and Community Design derived from Harbermas' Communicative Rationality. But the normative contentions do not progress any more to the stage of presenting practical strategies. This is the cause why there should be systematic approaches to reveal the relationships among various concepts or variables. With regard to the Community Design this study intends to take a statistical approach to find relationship between project scale and its accomplishment. The hypothesis that the smaller scale of project begets the better outcomes was tested to be rejected as a result of the analysis of variance. But the result also shows that appropriate density in relatively large area makes residents' expected satisfaction high. Although this discovery has its own meaning the tryout is anticipated to laying the cornerstone of quantitative analyses in the following studies.

"그리다"(peindre)와 "보다"(voir)의 존재론적,미학적 층위 연구 -Merleau-Ponty와 Cezanne을 중심으로-

김동윤 ( Dong Yoon Kim ) 한국기호학회 2014 기호학연구 Vol.39 No.-

본 글은 미학적 존재론의 관점에서 회화의 근본이 되는 ‘그리는 것’(peindre)과 ‘보는 것’(voir)에 대한 연구이다. 메를로 퐁티는 역저 『눈과 마음』(L`Oeil et l`esprit)에서 세잔, 마티스, 클레, 자코메티 등 근대 화가들의 예를 통해 회화의 본질에 대해 궁구한바 있다. 특히 세잔은 동 시대의 다른 화가들과 달리 회화의 기법이 아니라‘본다는것’과 ‘그린다는 것’과 같은 ‘회화의 진실’의 문제를 근본적으로 추구하였다. 그린다는 것은 지각과 몸의 현상으로서 심미적, 형이상학적. 존재론적 차원을 지닌다. 본다는 것(la vision)은 시각적인 것이 아니라 세계와 만나는 가장 근본적인 사건으로서 사물과 현상의 본질로 들어가는 행위이다. 메를로 퐁티에게 있어서 본다는 것은 몸을 통해 나와 사물이 교차하는 현상으로서 키아슴(chiasme), 뒤엉킴(entrelacs), 가역성(reversibilite) 등으로 표현된다. 몸과 세계의 교차성, 뒤엉킴, 키아슴의 존재론적 지평(horizon)이 가장 잘 드러나는 곳은 예술의 공간이다. 폴 발레리가 말하듯이, 화가는 ‘몸을 세계로 가져와 몸으로 세계를 표현’해야 하는 것이다. 몸으로 세계를 표현한다는 것은 기존 서구 근대회화의 재현방식에 대해 근본적인 물음을 제기하는 것이다. 회화가 재현이 아니라면, 회화가 바라보고 표현하는 세계는 표상으로서의 세계가 아니라 ‘살’의 세계(la Chair du Monde)인 것이다. ‘살’이란 현상학적 메타포로서 감각의 피륙으로서의 세계와 그것의 존재론적 층위가 드러나는 현상성 (phenominalite)과 차원(dimension)을 말한다. 그러므로 회화의 진실은 미메시스와 ‘그럴듯함’(la vraisemblance)의 재현이 아니라, 사물과 존재의 형상화이고 그것이 드러나는 사태(l`evenement)가 되는 것이다. 존재는‘저 쪽 어디에 있음’이 아니라 ‘드러남’(devoilement), ‘존재의 나뭇가지’(rameaux de l`Etre), 파열(fission), 만개 (deshiscence), 발광(illumination) 등의 메타포로서만 표현 가능하다. 지각의 대상인 존재와 세계는 언어의 차원을 벗어나서 사유될 수 없고, 의미와 하나를 이룬다는 의미에서 로고스(Logos)의 미학이 가능한 지점이고 - 메를로 퐁티의 말대로 - 미학적세계의 로고스(Logos du monde esthetique)인 것이다. Cette recheche a pour objectif de prendre en consideration la facon dont l`esthetique moderne voit la peinture du passe et de l`avenir. Merleau-Ponty, un des grands penseurs contemporains, explorait profondement un nouveau territoire de l`esthetique, tout en s`appuyant sur la nouvelle maniere de voir les Choses et le Monde. A travers la phenomenologie de la perception sensible, son interet d`esthetique sera naturellement porte sur la question de la peinture. Car la peinture est le seul moyen d`aller directement a l`essentiele des choses. Selon le philosophe, la peinture ne sera pas desormais definie par la representation mimetique au sens aristolecien du terme, mais plutot par la nouvelle facon de voir les choses et de rendre visible ce qui apparait invisible. Grace a cette nouvelle maniere de peindre les choses, l`art a pu rompre avec la tradition artistique essentiellement fondee sur l`imitation de la nature: l`art classique l`a appele la ≪vraisemblance≫ dont l`effet a ete fortement senti jusqu`au milieu du XIXe siecle. Dorenavant la vision et la perception sensible joueront le role majeur dans la maniere d`aborder la question de l`art, notamment la peinture apres l`impressionnisme dont l`impact a ete considerable dans l`histoire de l`art moderne. Parmi les peintres modernes, Paul Cezanne a pris un chemin fort particulier dans l`art, tout en cherchant la ≪verite de la peinture≫. Pour l`artiste aixois, ≪la verite de la painture≫ doit etre recherchee dans une nouvelle facon de percevoir la Nature qui lui a ete un des sujets les plus importants. Avant Cezanne les impressionnistes sont egalement tres interesses a la Nature mais leur peinture consistait essentiellement a decrire les effets de la lumiere refletee sur la surface des choses. Aux yeux de notre phenomenologue, cette technique impressioniste ne semblait pas assez pertiente pour explorer un nouveau territoire de la peinturel : la profondeur et l`epaisseur des choses, autrement dit `la Chair du Monde`. Car, selon Merleau-Ponty, la peinture ne doit pas demeurer une simple technique picturale mais doit etre l`expression de l`Etre puisee directement a la `nappe de l`Etre brut`. Comme Cezanne l`a bien montre, la vision doit comprendre une dimension de l`Etre ou l`oeil et l`esprit ne sont pas separes l`un de l`autre. Les composants de la peinture comme couleur, forme, ligne, mouvement, physionomie ne s`inscrivent plus dans le contexte de la peinture conventionnelle mais plutot dans la Chair du Monde. Comme la couleur et la forme de la representation mimetique ne sont que ‘couleur-silmulacre’, ‘forme-simulacre’, ≪la verite de la peinture≫ au sens cezannien du terme doit etre la sensation-revelation et l`expression des ‘rameaux de l`Etre‘. Le role nouveau assume par la creation artistique est d`exprimer le phenomene de l`illumination et de la deflagration de l`Etre-Logos: l`illumination ne sera que un des moments les plus eminents ou le mystere de la visibilite se revele. La peinture qui n`est plus l`art physico-optique doit suivre le mouvement dynamique de la Nature et du Monde. Comme dit Valery, le peintre, en apportant son corps au monde, participe a la creation d`un monde. En bref, en rehabilitant ce qu`il y avait prealablement avant l`arrivee de l`ere techno-scientifique, la peinture, expression du chiasme et de la reversibilite des Choses, mettra en jeu la Chair du Monde ou le Logos du monde esthetique tel qu`a defini Merleau-Ponty dans son oeuvrage principal, la Phenomenologie de la perception.

장 지오노 문학에 나타난 행복의 모럴과 생태적 사유에 관한 연구 - 『진정한 부Les vraies richesses』를 중심으로

김동윤(KIM Dong-Yoon) 프랑스학회 2005 프랑스학연구 Vol.32 No.-

보편교육을 위한 비버 챌린지

김동윤(KIM, Dong Yoon) 한국컴퓨터교육학회 2021 한국컴퓨터교육학회 학술발표대회논문집 Vol.25 No.2(B)

본 Tutorial에서는 모든 학생들이 4차 산업혁명에 가장 필요한 “복잡한 문제풀이 기술”을 습득하기 위하여 어떠한 소양을 갖추어야 하는지를 설명하고자 한다. 현재 대학 정보교육의 어려움과, 초중등 연계 교육이 어떻게 이루어져야 하는지 파악하고 이를 위해 현재 추진하고 있는 초중등 과정의 정보교육의 확대의 당위성을 이야기한다. 실제 초중등 정보교육에서 핵심적으로 다루어야 하는 컴퓨팅 사고(Computational Thinking)을 언급하고 이를 학습하는 적절한 도구로서 비버 챌린지에 대한 설명을 한다. 2016년에 한국에 도입된 비버 챌린지가 그간 어떻게 발전을 해 왔고, 이를 위해 어떠한 것들이 발표되고 출판되고, 학생들을 위한 교육 자료들이 얼마나 만들어졌는지를 언급한다. 그리고 앞으로의 게획을 특히 비버 챌린지와 프로그램을 연계하는 Self Study 5년 계획에 대하여도 발표하고자 한다.