• 한국수학사학회지
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• 제19권2호
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• pp.47-58
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• 2006

본 논문에서는 괴델의 삶과 업적을 소개하고, 그의 불완전성정리의 함의하는 바가 인식론적이고 윤리적인 의미를 가지는 여백을 확보하는데 있다는 것을 주장한다. 그리고 그 함의가 '여백의 철학'을 지지함을 논의한다.

• 한국산학기술학회논문지
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• 제16권7호
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• pp.4375-4380
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• 2015

선박용 디젤엔진 부품인 블랭크 단조품 가열 시 생산성 및 품질을 향상시키기 위하여 새로운 가열공정을 제안하였다. 본 연구에서는 새로운 블랭크 가열공정을 평가하고 가열공정 설계기준을 정립하기 위하여 수치해석 전용 프로그램인 ANSYS를 사용하여 재료의 비선형을 고려한 온도분포, 열응력 해석을 수행하였다. 가열조건은 승온단계와 유지단계로 구성되어 총 32시간이며 가열 시 시간경과에 따른 블랭크 내 외부의 온도분포와 열응력 변화를 평가하였다. 그 결과 가열 시 승온단계에서 블랭크 내 외부 온도차는 시간이 경과함에 따라 점차 증가하여 최종 승온단계에서 최대 온도차가 발생하나 유지단계에서 온도차는 점진적으로 감소하는 반면에 가열이 시작되어 10시간 경과 후 블랭크 내부에는 최대 등가응력 $12.5kg/mm^2$가 발생한다는 것을 알 수 있다. 따라서 단조품 가열공정을 설계함에 있어서 가열 후 10시간 경과 시, 즉 노내 온도 $650^{\circ}C$에서 블랭크 내 외부 온도차는 $150^{\circ}C$이내가 되도록 관리해야 한다.

• 대한약침학회지
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• 제3권1호
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• pp.65-87
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• 2000

This study was designed to evaluate the effect of the bee venom(BV) aqua-acupuncture on the neuronal activities of catecholaminergic(tyrosine hydroxylase : TH, dopamine ${\beta}$ hydroxylase : D${\beta}$H) system in the brainstem. After the BV aqua-acupuncture was applied on Chok-Samni(ST36) and the gluteal part(Blank locus) in rats. Also, the number of colocalization between catecholamine containing neurons and Fos immunoreactive neurons were analyzed by using the double immunohistochemical technique. The results of the experiments were summarized as follows : 1. In DR and LC, Chok-Samni group and the Blank locus group showed more significant increase in the number of colocalization between TH containing neurons and Fos immunoreactive neurons than the control group. Furthermore, Chok-Samni group showed more significant increase than the Blank locus group. Also, in Arc, Chok-Samni group showed more significant increase than the Blank locus group and the control group. 2. In LC, Chok-Samni group showed more significant increase in the number of colocalization between D${\beta}$H containing neurons and Fos immunoreactive neurons than the Blank locus group and the control group. Also, in A5, Chok-Samni group and the Blank locus group showed more significant increase than the control group. Chok-Samni group showed more significant increase than the Blank locus group. However, there was no significant change in A7. Consequently, the BV aqua-acupuncture increased more potent the number of Fos immunoreactive neurons and the activity of catecholaminergic neurons. Furthermore, the BV aqua-acupuncture was more effective on Chok-Samni than Blank locus group. These results indicate that the BV aqua-acupuncture is very effective therapy to control pain. The therapeutic effect of BV aqua-acupunture may associated with the endogenous modulatory system such as catecholamine. Those data from the study can be applied to establish the effective treatment of the BV for pain control in the clinical field.

• 대한토목학회논문집
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• 제39권4호
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• pp.513-521
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• 2019

본 연구의 목적은 지하철 이용자의 지하철 표지 여백에 대한 특성의 군집그룹별 선호도를 파악하는 것이다. 세부적으로 성별, 연령 등의 특성에 따라 지하철 표지 여백에 대한 특성을 다양하게 디자인하는 개념을 도입하는 것을 목적으로 한다. 본 연구는 지하철 표지 여백에 대한 특성의 선호도를 조사하고 전체그룹과 군집그룹별 선호도를 분석하였다. 선호도 조사를 위해 설문조사를 실시하였으며, 선호도 분석을 위해 군집분석을 실시하고 전체그룹과 군집그룹의 인구통계학적 분석과 컨조인트 분석을 실시하였다. 선호도 조사를 위한 지하철 표지 여백에 대한 특성의 속성은 상하여백, 측여백, 테두리선 여백, 화살표 두께, '역명'과 '호선번호' 순서로 설정하였다. 선호도 분석 결과는 다음과 같다. 전체그룹에서 속성의 중요도는 테두리선 여백, '역명'과 '호선번호' 순서, 측여백, 상하여백, 화살표 두께 순으로 나타났다. 군집그룹은 총 3개의 그룹으로, 1군집은 지하철을 거의 매일, 일주일에 3~4회 이용하는 여성으로, 글자의 1/2 측여백을 선호하는 것으로 나타났다. 2군집은 60대 이상의 지하철 표지를 불편하다고 생각하는 이용자로, 테두리가 없는 것과 '역명'+'호선번호' 순서를 선호하는 것으로 나타났다. 3군집은 20대와 30대의 남성으로, 글자의 1/5 테두리선 여백과 얇은 화살표 두께를 선호하는 것으로 나타났다. 결론은 다음과 같다. 첫째, 지하철 표지 여백에 대한 특성을 일관성 있게 디자인 해야하지만, 특정지역 혹은 노선에 대해서 성별, 연령별, 지하철 이용횟수에 따라 다양하게 고려할 필요성이 제시되었다. 둘째, 특정지역 혹은 노선에 따라서는 지하철 표지 여백에 대한 특성의 표지를 표준화된 한 가지 유형이 아닌 두 가지 이상의 유형의 디자인이 가능함을 보여주었다.

• 한국해양공학회지
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• 제13권3호통권33호
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• pp.21-28
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• 1999

In this paper, a finite element method for the determination of initial blank shape in sheet metal forming process will be introduced. The initial blank shape is determined by the only one step from the final to the initial blank. The used finite element inverse method adopted Henky's deformation theory, Hill's anisotropic yield criterion and simplified boundary conditions. Based on this theory. a three-dimensional membrane finite element code was developed. The developed code will be applied to several sheet metal forming examples for the demonstration of its validity.

• 소성∙가공
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• 제8권1호
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• pp.7-13
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• 1999

In this study, side panels were developed using the laser-welded tailored blank (T.B.) of both the same thickness and different thickness. At first, the formability of the same thickness T.B. was investigated to compare with one of the non-welded panel with respect to weldline movement and strain distribution in blank during the stamping process. Based on these results, we determined the weld line positions and the die step for T.B. forming of the blanks composed of different thickness combination. Then we made some stamping tryouts with selected types of blanks to investigate the formability of T.B. of the different thickness. During the tryouts, wrinkles were found in the a-pillar lower region which is under the deformation mode of the shrink flange. In the b-pillar region, fractures were also found. These defects have been reduced and corrected by controlling the blank design, the die faces and process parameters.

• 소성∙가공
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• 제8권4호
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• pp.347-355
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• 1999

The paper is concerned with an improved scheme for application of the blank holding force in order to take account of the thickness distribution in the sheet material of the flange region. The scheme incorporates with a modified membrane finite element method for planar anisotropic materials. The new scheme proposed two coefficients α and βto calculate the compressive stress in the sheet metal due to the blank holding force, which should be determined properly for accurate analysis. The effect of αand βon the blank holding force distribution and the deformed shape is investigated with simulation of rectangular cup deep drawing processes by changing parameter values.

• 대한기계학회논문집A
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• 제24권1호
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• pp.79-86
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• 2000

In this study, a method of optimal blank design using the sensitivity analysis has been proposed. To get sensitivity a well-known commercial code PAM-STAMP has been used. In order to verify this method, formings of square cup, clover shaped cup and L shaped cup have been chosen as the examples. With the predicted optimal blank both computer simulation and experiment are performed. Excellent agreements are recognized between the numerical results and the target contour shapes. Through the investigation, the proposed systematic method of optimal blank design is found to be effective in the design of the deep drawing process.

• 소성∙가공
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• 제13권4호
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• pp.307-318
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• 2004

Rectangular drawn case with extreme aspect ratio is widely used for electrical parts such as a lithium-ion battery container, semi-conductor case and so on. Additionally, from the recent trend towards miniaturization of the multi-functional mobile device, demands for rectangular case with the narrow width are increased. In this study, numerical and experimental approaches for the multi-stage deep drawing process have been carried out. Based on the research results of the width of 5.95mm model, finite element analysis for storage case of rectangular cup type was verified to the width of 4.95mm. Also, a series of manufacturing experiments for rectangular case is conducted and the deformed configuration of the rectangular drawn case are investigated by comparing with the results of the numerical analysis. And the modification of the initial blank is performed to minimize the trimmed material amount. By the application of the modified blank, the sound shape of the deformed parts is improved.

• 소성∙가공
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• 제10권3호
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• pp.235-245
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• 2001

Deep drawing process, one of sheet metal forming methods, is very useful in the industrial field because of its efficiency The deep drawing is affected by many process variables, such as blank shapes, shape radii of the punch and die, formability of materials and so on. Especially, blank shape is very important formability factor. In this study, in order to investigate the effects of blank shape, we suggested three kinds of blank shapes and examined friction test about three conditions. We measured punch load distribution according to punch stroke under the conditions of each punch and die shape radii and observed punch load of elliptical cup forming.