• Current Optics and Photonics
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• 제7권3호
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• pp.273-282
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• 2023

This paper presents a new method for redistributing effectively the first orders of each lens element to achromatize and athermalize an optical system, by introducing a novel method for adjusting the slope of an achromatic and athermal line. This line is specified by connecting the housing, equivalent single lens, and aberration-corrected point on a glass map composed of available plastic and glass materials for molding. Thus, if a specific lens is replaced with the material characterized by the chromatic and thermal powers of an aberration-corrected point, we obtain an achromatic and athermal system. First, we identify two materials that yield the minimum and maximum slopes of the line from a housing coordinate, which specifies the slope range of the line spanning the available materials on a glass map. Next, redistributing the optical first orders (optical powers and paraxial ray heights) of lens elements by moving the achromatic and athermal line into the available slope range of materials yields a good achromatic and athermal design. Applying this concept to design a mobile-phone camera lens, we efficiently obtain an achromatic and athermal system with cost-effective material selection, over the specified temperature and waveband ranges.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.104-107
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• 2007

An aspheric microlens array to improve the properties of multi optical probes was designed and fabricated. To generate multi optical probes with good qualities, a microlens array with the minimum spherical aberration was designed by ray tracing. Using the reflow process, a master pattern of aspheric microlens array was made and finally with the ultraviolet-imprinting (UV-imprinting) method, the aspheric microlens array was replicated. The reflow condition was optimized to realize the master pattern of the microlens array with the designed aspheric shape. The intensity distribution of the optical probes at the focal plane showed a diffraction-limited shape.

• Journal of information and communication convergence engineering
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• 제11권2호
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• pp.139-146
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• 2013

This paper proposes a new spatial filtering approach for increasing the depth-of-field (DOF) of imaging systems, which is very useful for obtaining sharp images for a wide range of axial positions of the object. Many different techniques have been reported to increase the depth of field. However the main advantage in our method is its simplicity, since we propose the use of purely absorbing beam-shaping elements, which allows a high focal depth with a minimum modification of the optical architecture. In the filter design, we have used the analogy between the axial behavior of a system with spherical aberration and the transverse impulse response of a 1D defocused system. This allowed us the design of a ring-shaded filter. Finally, experimental verification of the theoretical statements is also provided.

• Journal of Astronomy and Space Sciences
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• 제15권2호
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• pp.359-371
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• 1998

본 연구에서는 원자외선 영역($900~1750AA$)에서 오로라, 주/DIRKS 대기 광 관측 및 천문학적 관측을 동시에 수행하기 위한 FUVS(Far Ultraviolet Spectrograph)를 설계하고, 그 성능을 평가하였다. FUVS의 설계는 에돌이발(grating)의 광학적 특성과 비구면 광학을 충분히 고려하여 이루어졌으며, 분해능 계산을 위해 ray-trace 방법과 파면수차 계산에 의한 방법을 사용하여 설계의 검증을 시도하였다. 두 가지 방법에 의한 결과가 오차범위 안에서 일치하여 분석 방법에 큰 문제점이 없다는 것을 간접적으로 확인할 수 있었고, 전 영역에 걸쳐 대략 $2~5AA$의 분해능을 얻었다. 또한, FUVS의 수행 임무 중 가장 검출이 힘들 것으로 생각되는 고온의 성간 플라즈마에서 방출되는 선 방출의 검출 가능성을 타진하기 위하여 FUVS의 최소 검출가능 플럭스(MDF)를 계산하였다. 이 계산을 위하여 지금까지 알려진 반사물질, MCP 등의 특성을 충분히 고려하였으며, 선의 세기에 따라 하루에서 일주일에 걸친 관측을 통해 고온의 성간 플라즈마에서 방출되는 선 방출을 검출할 수 있다는 결론을 얻었다.

• 품질경영학회지
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• 제44권4호
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• pp.799-811
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• 2016

Purpose: The conjoint analyst in marketing are interested in detecting whether there exist synergy or antagonistic effects between two attributes. In the cases where attributes have two or three levels, we research on the design of survey questionnaire to estimate all the main effect and as many two factor interaction effects as possible. Methods: We consider the balanced incomplete block (BIB) mixed level factorial design $2^f{\times}3^g$ or fractional factorial design. To reduce the number of questions in a questionnaire, we propose the balanced incomplete block mixed level design with minimum aberration which is generated by implementing proc factex in SAS. Also, we propose using two or three level BIB factorial design instead of mixed level designs by transforming three level attributes into two attributes of two levels and two level attribute into three level attribute by using dummy level technique. Results: We propose three methods for designing survey questionnaire where the block and design generators are found with practical number of questions in a questionnaire. By analyzing all the respondents survey data generated by the simulation study, we find the proper model and do the concepts optimization. Conclusion: The proposed methods of designing survey questionnaires seem to perform well in the sense that the proper model, and then the optimal concept is found in a case study where all the respondents survey data are generated by the simulation study.

• 한국간담췌외과학회지
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• 제27권3호
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• pp.264-270
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• 2023

Backgrounds/Aims: Proximal splenorenal shunt (PSRS) is a commonly performed procedure to decompress portal hypertension, in patients with refractory variceal bleed, especially in non-cirrhotic portal hypertension (NCPH). If conventional methods are hindered by any technical or pathological factors, alternative surgical techniques may be required. This study analyzes the effectiveness of various unconventional shunt surgeries performed for NCPH. Methods: A retrospective analysis of NCPH patients who underwent unconventional shunt surgeries during the period July 2011 to June 2022 was conducted. All patients were followed up for a minimum of 12 months with doppler study of the shunt to assess shunt patency, and upper gastrointestinal endoscopy to evaluate the regression of varices. Results: During the study period, 130 patients underwent shunt surgery; among these, 31 underwent unconventional shunts (splenoadrenal shunt [SAS], 12; interposition mesocaval shunt [iMCS], 8; interposition PSRS [iPSRS], 6; jejunal vein-cava shunt [JCS], 3; left gastroepiploic-renal shunt [LGERS], 2). The main indications for unconventional shunts were left renal vein aberration (SAS, 8/12), splenic vein narrowing (iMCS, 5/8), portalhypertensive vascular changes (iPSRS, 6/6), and portomesenteric thrombosis (JCS, 3/3). The median fall in portal pressure was more in SAS (12.1 mm Hg), and operative time more in JCS, 8.4 hours (range, 5-9 hours). During a median follow-up of 36 months (6-54 months), shunt thrombosis had been reported in all cases of LGERS, and less in SAS (3/12). Variceal regression rate was high in SAS, and least in LGERS. Hypersplenism had reversed in all patients, and 6/31 patients had a recurrent bleed. Conclusions: Unconventional shunt surgery is effective in patients unsuited for other shunts, especially PSRS, and it achieves the desired effects in a significant proportion of patients.