• Current Optics and Photonics
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• v.7 no.3
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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.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2007.10a
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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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• v.11 no.2
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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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• v.15 no.2
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• pp.359-371
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• 1998

We present the design specifications and the performance estimation of the FUVS (Far Ultraviolet Spectrograph) proposed for the observations of aurora, day/night airglow and astronomical objects on small satelltes in the spectral range of $900~1750AA$. The design of FUVS is carried out with the full consideration of optical characteristics of the grating and the aspheric substrate. Two independent methods, ray-tracing and the wave front aberration theory, are employed to estimate the performance of the optical design and it is verified that both procedures yield the resolution of $2~5AA$ in the entire spectral range. MDF (Minimum Detectable Flux) is also estimated using the known characteristics of the reflecting material and MCP, to study the feasibility of detection for faint emission lines from the hot interstellar plasmas. The results give that the observations from 1 day to 1 week, depending on the line intensity, can detect such faint emission lines from diffuse interstellar plasmas.

• Journal of Korean Society for Quality Management
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• v.44 no.4
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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.

• Annals of Hepato-Biliary-Pancreatic Surgery
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• v.27 no.3
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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.