• Korean Journal of Optics and Photonics
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• v.4 no.4
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• pp.373-380
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• 1993

A five mirror system with a reduction magnification(M=+1/5) is designed for DUV optical lithography. Initially, numerical solutions of all zero 3rd order aberrations and zero 5th order spherical aberration are obtained for the spherical mirror system. Next, by the optimization method, the aspherization is carried out to the two spherical mirrors to obtain a system that has as less residual aberrations, higher NA and improved MTF as possible. We have finally obtained the system of which NA is 0.45 and the resolution is about 500 cycles/mm at the 50% MTF value criterion and the depth of focus of $1.0{\mu}m$ for the nearly incoherent illumination$({\sigma}=1.0)$ and the wavelength of 0.248 m(KrF excimer laser line).

• Proceedings of the KIEE Conference
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• 1988.07a
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• pp.315-318
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• 1988

THE STUDY ABOUT CHARACTERISTICS OF PHOTO RESIST ITSELF (MINIMUM RESOLUTION, DEPTH OF FOCUS MARGIN AND CRITICAL DIMENSION CONTROL LATITUDE) WAS DONE AND REPORTED. THREE TYPES OF PHOTO RESISTS WERE TESTED. THE FIRST IS THE LOW MOLECULAR WEIGHT PHOTO-RESIST SHOWING THE NARROW DISTRIBUTION OF MOLECULAR WEIGHT (LOW MOLECULAR WEIGHT CONTROL TYPE), THE SECOND IS A PHOTO-RESIST CONTAINING THE INNER CONTRAST ENCHANCEMENT MATERIAL (INNER CEM TYPE) AND THE THIRD IS A NORMAL PHOTO-RESIST (HIGH MOLECULAR WEIGHT TYPE). THE INNER CEM TYPE AND THE LOW MOLECULAR WEIGHT CONTROL TYPE PHOTO-RESIST ARE MORE IMPROVED PHOTO-RESISTS. IT PROVED THAT THE MINIMUM RESOLUTION WAS IMPROVED BY 0.2 - 0.3 um, THE DEPTH OF FOCUS MARGIN WAS IMPROVED BY 0.8 - 1.2 um AND THE C.D. CONTROL LATITUIDE WAS IMPROVED.

• Current Optics and Photonics
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• v.7 no.4
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• pp.398-407
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• 2023

We explored a method to evaluate imaging performance for the optimal assembly of an endoscopic miniature lens and a sensor constituting an imaging module at the distal end of gastrointestinal endoscopy. For the assembly of the imaging module, the image sensor was precisely located at the focal plane when collimated light passed through the endoscopic lens. As another method, the distance between the lens and sensor was adjusted to obtain the highest focus index from images measured the star chart of the International Organization for Standardization (ISO) standard at various positions. We analyzed the slanted-edge modulation transfer function (MTF), corresponding depth of field, and number of line pairs for MTF 50% and 20% at each working distance within the range of 5-100 mm for imaging modules assembled in different ways. Assembly conditions of the imaging module with better MTF performance were defined for each working distance range of 5-30 mm and 30-100 mm, respectively. In addition to the MTF performance, the focus index of each assembled module was also compared. In summary, we examined the performance of imaging modules assembled with different methods within the suggested working distance and tried to establish the optimal assembly protocol.

• Korean Journal of Optics and Photonics
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• v.7 no.2
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• pp.101-111
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• 1996

Optical microscopes integrated with CCD cameras are widely used for automatic inspection of precision circuit patterns fabricated on glass masks and silicon wafers. For this application it is important to position the object always is focus so that the image appears in good quality while the microscope scans the object. However, as the magnification of the microscope is taken large for fine resolution the depth of focus becomes small, often in submicron ranges, requiring special care in focusing. This study proposes a new auto-focusing method, which can be readily incorporated in existing optical configuration of microscope. This method is based on optical triangulation using a separate beam of laser and two photodiodes, eliminating focus errors caused by surface roughness and waviness. Experimental results prove that the method can produce focus error signals which are very sensitive with a resolution of 5 nm within 0.5 ${\mu}{\textrm}{m}$ accuracy.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.4B
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• pp.353-360
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• 2011

The objectives of this study were to analyzes temporal variation of local scour depth in the downstream of weir with shapes. Prediction of maximum or equilibrium scour depth was the main focus of engineers and researchers in the downstream of weir. However, it is necessary to analyzes temporal variation of local scour depth in the downstream of weir to predict real time scour depth. Experiment were performed with various weir shapes like sharp crest and inclined stepped with time variation and non-dimensional scourhole shapes, scour depths were proposed. A formula for predicting scour depths with temporal variation for weir were proposed through non-linear regression analysis. Temporal variation of scour depths could be estimated with suggested formula and 4 input data (Equilibrium scour depth, weir height, overflow depths, and water depth downstream). Suggested formula could make it possible to design a apron and bed protection economically in the downstream of a weir by considering flood duration time.

• Quality Improvement in Health Care
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• v.27 no.2
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• pp.2-17
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• 2021

Purpose: The purpose of this study is to seek in-depth perspectives of stakeholders on the necessity and specific criteria for designating a specialized hospital for urologic diseases. Methods: Eight participants experts in urology medicine and specialized hospital system were divided into four groups. Following the semi-structured guidelines, an in-depth interview was conducted twice and a focus group discussion was conducted three times. All the interviews were transcribed verbatim and analyzed. Results: The majority of participants predicted that there would be demand for specialized hospitals for urologic diseases. The criteria of designating a specialized hospital, such as the number of hospital beds and quality of health care, have to be modified in consideration of the specificity of urology. The introduction of a specialized hospital would improve the healthcare delivery system, positively affecting hospitals and patients. Furthermore, government support is essential for the maintenance of specialized hospital systems as urology hospitals experience difficulties in generating profits. Conclusion: This study is expected to be used as base data for introducing and operating a specialized hospital for urologic diseases. In addition, it is expected that the methodology and results of this study would encourage follow-up studies on specialized hospitals and provide guidelines to evaluate the effectiveness of such hospitals in other medical fields.

• International Journal of Advanced Culture Technology
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• v.8 no.3
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• pp.280-284
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• 2020

In the rapidly changing science and technology environment, an in-depth understanding of users of STEM information is an essential factor in designing a user-centered information system. The purpose of this study is to investigate and analyze in-depth the behaviors and needs of users who use STEM information. In this study, the needs of users for STEM information and STEM information sites are dealt with in depth using the FGI qualitative method. In addition, it includes the analysis results of grouping of similar sites according to various aspects of use of STEM information sites. As a result of grouping similar sites based on awareness and level of use,, they were grouped by domestic-international, paid-free, integrated-specific fields. As a result of grouping similar sites according to the purpose of use, they were grouped by domestic and international papers, research reports, and patents. As a result of grouping similar sites according to usage attributes, they were grouped by diversity, reliability, and specialization. As for the positions of similar sites perceived by users, Science Direct and PubMed showed high specialization and high quality, Google Scholar showed integration and popularity, and RISS showed four attributes evenly. Suggestions for information system design are discussed.

• The KIPS Transactions:PartB
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• v.17B no.1
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• pp.55-62
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• 2010

Human visual attention system has a remarkable ability to interpret complex scenes with the ease and simplicity by selecting or focusing on a small region of visual field without scanning the whole images. In this paper, a novel feature map generation and integration method for attention based visual information processing system is proposed. The depth information obtained from a stereo pair of images is exploited as one of spatial visual features to form a set of topographic feature maps in our approach. Comparative experiments show that correct detection rate of visual attention regions improves by utilizing depth feature compared to the case of not using depth feature.

• Geomechanics and Engineering
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• v.7 no.4
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• pp.459-475
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• 2014

In this study, a CPT-based p-y analysis method was proposed for the displacement analysis of laterally loaded piles. Key consideration was the continuous soil profiling capability of CPT and cone resistance profiles that do not require artificial assumption or simplification for input parameter selection. The focus is on the application into offshore mono-piles embedded in clays. The correlations of p-y function components to the effective cone resistance were proposed, which can fully utilize CPT measurements. A case example was selected from the literature and used to validate the proposed method. Various parametric studies were performed to examine the effectiveness of the proposed method and investigate the effect of property profile and its depth resolution on the p-y analysis. It was found that the calculation could be largely misleading if wrongly interpreted sub-layer condition or inappropriate resolution of input soil profile was involved in the analyses. It was also found that there is a significant influence depth that dominates overall load response of pile. The soil profile and properties within this depth range affect most significantly calculated load responses, confirming that the soil profile within this depth range should be identified in more detail.

• Korean Journal of Cognitive Science
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• v.17 no.4
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• pp.287-301
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• 2006

Two experiments were performed to investigate effects of background depth information on the judgment of two-dimensional shapes, using the Posner et al.'s(1969) physical match task. In both experiments, the focus was on whether the background depth information affects the decisions of physical shape sameness of two letters or figures presented successively. In Experiment 1, artificially constructed rues of linear perspective and texture gradient were used, whereas cues contained in a real road situation were used in Experiment 2. The results of both experiments showed that the depth cues affect the perception of two-dimensional shapes. That is, when two stimuli of the same physical shape were likely to be perceived differently due to the given depth cues, response accuracies('yet' in this case) decreased and reaction tines of physical match increased. And when two stimuli of the different physical shape were likely to be perceived the same due to the given depth cues, response accuracies('no' in this case) decreased and reaction times of physical match increased likewise. These results wert discussed in terms of some conceptual methodological problems of the previous studies on the shape constancy and the directions of future research.