유한 물체 거리를 갖는 2 반사경계의 곡률 선형 방정식

이정기,임천석,Lee, Jung-Gee,Rim, Cheon-Seog 한국광학회 2005 한국광학회지 Vol.16 No.5

In this paper, we propose easily tooling method for Seidel third order aberration, which are not well utilized in actual design process due to the complication of mathematical operation and the difficulty of understanding Seidel third order aberration theory, even though most insightful and systematic means in pre-designing for the initial data of optimization. First, using paraxial ray tracing and Seidel third order aberration theory, spherical aberration coefficient is derived for a two-mirror system with a finite object distance. The coefficient, which is expressed as a higher-order nonlinear equation, consists of design parameters(object distance, two curvatures, and inter-mirror distance) and effective focal length(EFL). Then, the expressed analytical equation is solved by using a computer with numerical analysis method. From the obtained numerical solutions satisfying the nearly zero coefficient condition($<10^{-6}$), linear fitting process offers a linear relationship called the curvature linear equation between two mirrors. Consequently, this linear equation has two worthy meanings: the equation gives a possibility to obtain initial design data for optimization easily. And the equation shows linear relationship to a two-mirror system with a finite object distance under the condition of corrected third order spherical aberration. 본 연구는, 원리적인 다양한 장점에도 불구하고 현실적인 제약으로 인해 실제 설계과정에서 잘 적용되지 않는, 자이델 3차 수차를 간편하게 다룰 수 있는 방안을 제안한다. 먼저 유한 물체거리를 갖는 2 반사경계에 대해 자이델 3차의 구면수차계수를 유도한다. 여기서, 유도된 구면수차계수는 고차의 비선형 방정식으로 표현되는데, 그 구성은 설계변수(물체거리, 주경 및 부경의 곡률, 주경과 부경 사이의 거리)와 유효초점거리로 이루어진다. 해석적으로 표현된 고차의 비선형 구면수차 방정식은 컴퓨터를 이용한 수치기법에 의해 근사적인 제로조건을 만족하도록 풀려진다. 이렇게 구해진 다양한 수치 해들을 주의 깊게 통찰하면 주경과 부경의 곡률 간에 선형성이 존재함을 파악할 수 있다. 즉, 결과적으로 주경과 부경의 곡률들을 선형맞춤(linear fitting)하면 곡률선형방정식이 얻어지는데, 이의 의미는 약간의 대수적인 계산으로 최적화의 초기 입력 데이터를 손쉽게 얻을 수 있는 가능성을 제시한 것이다. 한편, 응용외의 순수 수차론적인 관점에서 본다면, 본 연구의 특징은 유한 물체거리를 갖는 2 반사경계의 주경 및 부경의 곡률들이 구면수차가 거의 제로가 되는 조건 하에서 상호간에 선형 관계가 존재하였다는 것이다.

군ㆍ관 합동공사 시공사례

이정기 대한토목학회 1998 대한토목학회지 Vol.46 No.6

Whirling machine의 성능 개선을 위한 연구

이정기,양우석,손재석,한희덕,김한수,Lee Jung-Ki,Yang Woo-suk,Son Jea-seok,Han Hui-duck,Kim Han-soo 대한기계학회 2005 大韓機械學會論文集A Vol.29 No.10

In order to meet the increasing competitive pressures coupled with higher demands for component quality, whirling machines have been at the cutting edge of the automobile industry for more than 25 years. The hard whirling process can save on machining time and operation elimination. Hard whirling is done dry, without coolant. The chips carry away nearly all of the heat during cutting, leaving the workpiece cool and minimizing any thermal geometry variations. The surface finish and profile accuracy are close to grinding quality. Whirling machines usually consist of four major parts; 1) loading system that requires the necessary axial speeds, 2) head stock that needs high precision clamping and positioning system at the chuck and tailstock, 3) whirling unit that demands the high cutting speeds and cutting power fer cutting deep thread profiles and 4) unloading system that requires an easy workpiece unloading. Also, capabilities of the whirling machine can be improved by attaching a vision system to the machine. Most of whirling machines in Korean automobile industry are imported from the Leistritz company, Germany and the Hasegawa company, Japan. Tn this paper, a basic research will be performed to improve and enhance the existing whirling machines. Finally, a new Korean whirling machine will be proposed and developed.

한국 성소수자 광고의 특성과 허용 필요성에 관한 탐색 - 성소수자 광고 불허 및 허용 사례를 중심으로

이정기,황우념 경성대학교 사회과학연구소 2019 社會科學硏究 Vol.35 No.3

이 연구는 한국 성소수자 광고의 유형을 규명하고, 한국 성소수자 광고 규제론자들의 주장 근거가 무엇인지, 한국 성소수자 광고 규제의 사례와 법적 근거가 무엇인지 확인해 보고자 했다. 이 연구결과는 다음과 같다. 첫째, 한국 성소수자 광고는 의견 광고의 형태가 많았고, 활용매체는 신문과 옥외 매체에 한정됐다. 모든 광고는 비상업적 형태의 광고였다. 둘째, 한국 성소수자 광고의 규제 찬성 논거는 아동과 청소년 보호의 필요성, 이성애자 이익 보호의 필요성으로 요약된다. 반면, 규제 반대 논거는 소수자 차별은 인권침해라는 논리로 귀결되고 있었다. 셋째, 성소수자 광고를 규제해야 한다고 본 5건 사례의 유형은 옥외 광고의 형태로 나타났고, 대부분 의견 광고였다. 5개 규제 사례의 규제 근거는 대부분 옥외광고물 등 관리법 제5조 제2호와 3호로 나타났다(5건 중 4건). 민원 소지가 있다는 이유에서 규제된 사례도 2건 존재했다. 넷째, 성소수자 광고를 허용해야 한다고 본 5건 사례의 유형은 옥외 광고와 의견 광고였다. 아울러 허용의 근거는 국가인권위원회법 제2조 제3호의 평등권 침해(5건 중 4건), 헌법 제21조 표현의 자유(5건 중 3건)로 나타났다. 즉 한국 성소수자 광고 허용의 핵심근거는 소수자의 표현의 자유 보호인 것으로 나타났다. 이 연구는 이상의 연구결과를 바탕으로 성소수자 광고 규제 담론이 타당한 것인지에 대한 논의를 수행했다. This study set out to examine the types of sexual minority advertising in South Korea and figure out the grounds for the regulation of sexual minority advertising in the nation among its advocates and the cases and legal founds of regulating sexual minority advertising in the nation. The results of this study are as follows: First, many sexual minority advertisements in South Korea took the form of opinion advertising, and their media was restricted to newspapers and outdoor sources . They were all non-commercial advertisements. Second, the grounds for the regulation of sexual minority advertising in the nation were summarized into a need to protect children and adolescents and the interest of heterosexuals. The grounds against the regulation of sexual minority advertising boiled down to the human right violation of minority discrimination. Third, outdoor advertising was found in all five cases for the regulation of sexual minority advertising with most being opinion advertising. The grounds for their regulation were mostly Article 5, Clauses 2 and 3 of Act on the Control of Outdoor Advertisements, etc (four of five). Civil complaint was the reason for regulation in two cases. Finally, outdoor and opinion advertising formats were found in five cases for the approval of sexual minority advertising. Their grounds were the provisions about the violation of equal rights in Article 2, Clause 3 of National Human Rights Commission Act (four of five) and those about the freedom of expression in Article 21 of the Constitution (three of five). Based on these findings, the study discussed whether the discourse was valid about the regulation of sexual minority advertising.

합성상형의 유한요소 해석

이정기,조진구,박근수 한국농공학회 1987 한국농공학회논문집 Vol.29 No.3

This paper suggests a method for the analysis of box girders which are subject to the membrane and the plate bending actions, Moreover, the method is applied to the box girders under distributed loads which have various geometrical types of cross sections and are made out of different materials. The approach is based on the finite element technique in which the structure is considered to be a spatial assemblage of flat plate elements and the deformations of the plates are to be approximated with 9-noded parabolic isoparametric elements. The results are summarized as follows. 1.In all models, the larger the widths of top flange inside of web are, the larger the vertical deflections are. 2.The maximum transverse and longitudinal moments in the composite box girders are judged to be larger than those in the RC box girders. 3.The transverse and the longitudinal moments in top flange of composite box. girders are larger than those in that of the RC box girders. 4.The transverse and longitudinal moments in web and bottom flange of the composite box girders are estimated to be very small in compare to those in web and bottom flange of the RC box girders.

1988년도 에너지절약 시설자금 융자 지원안내

이정기,Lee, Jeong-Gi 한국설비기술협회 1988 설비 : 공조ㆍ냉동ㆍ위생 Vol.5 No.9

'보일러에 이상이 있을때'(I)

이정기 전국보일러설비협회 1989 보일러설비 Vol.7 No.-

'보일러에 이상이 있을때'(II)

이정기 전국보일러설비협회 1989 보일러설비 Vol.8 No.-

[21C프론티어 연구 개발사업] 나노메카트로닉스 기술개발 사업소개

이정기,이상록 대한기계학회 2006 기계저널 Vol.46 No.3

혼합 체적-경계 적분방정식법을 이용한 탄성해석 방법 개발

이정기,허강일,진원재,Lee, Jeong-Gi,Heo, Gang-Il,Jin, Won-Jae 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.4

A Mixed Volume and Boundary Integral Equation Method is applied for the effective analysis of elastic wave scattering problems and plane elastostatic problems in unbounded solids containing general anisotropic inclusions and voids or isotropic inclusions. It should be noted that this newly developed numerical method does not require the Green's function for anisotropic inclusions to solve this class of problems since only Green's function for the unbounded isotropic matrix is involved in their formulation for the analysis. This new method can also be applied to general two-dimensional elastodynamic and elastostatic problems with arbitrary shapes and number of anisotropic inclusions and voids or isotropic inclusions. In the formulation of this method, the continuity condition at each interface is automatically satisfied, and in contrast to finite element methods, where the full domain needs to be discretized, this method requires discretization of the inclusions only. Finally, this method takes full advantage of the pre- and post-processing capabilities developed in FEM and BIEM. Through the analysis of plane elastostatic problems in unbounded isotropic matrix with orthotropic inclusions and voids or isotropic inclusions, and the analysis of plane wave scattering problems in unbounded isotropic matrix with isotropic inclusions and voids, it will be established that this new method is very accurate and effective for solving plane wave scattering problems and plane elastic problems in unbounded solids containing general anisotropic inclusions and voids/cracks or isotropic inclusions.