• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3772-3783
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• 2021

This work proposes a new efficient meta-heuristic optimization algorithm called Gamma Ray Interactions Based Optimization (GRIBO). The algorithm mimics different energy loss processes of a gamma-ray photon during its passage through a matter. The proposed novel algorithm has been applied to search for the global minima of 30 standard benchmark functions. The paper also considers solving real optimization problem in the field of nuclear engineering, radioisotope identification. The results are compared with those obtained by the Particle Swarm Optimization, Genetic Algorithm, Gravitational Search Algorithm and Grey Wolf Optimizer algorithms. The comparisons indicate that the GRIBO algorithm is able to provide very competitive results compared to other well-known meta-heuristics.

• Structural Engineering and Mechanics
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• v.52 no.3
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• pp.445-468
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• 2014

In this paper a new particle swarm ray optimization algorithm is proposed for truss shape and size optimization with natural frequency constraints. These problems are believed to represent nonlinear and non-convex search spaces with several local optima and therefore are suitable for examining the capabilities of new algorithms. The proposed algorithm can be viewed as a hybridization of Particle Swarm Optimization (PSO) and the recently proposed Ray Optimization (RO) algorithms. In fact the exploration capabilities of the PSO are tried to be promoted using some concepts of the RO. Five numerical examples are examined in order to inspect the viability of the proposed algorithm. The results are compared with those of the PSO and some other existing algorithms. It is shown that the proposed algorithm obtains lighter structures in comparison to other methods most of the time. As will be discussed, the algorithm's performance can be attributed to its appropriate exploration/exploitation balance.

• Proceedings of the Korean Nuclear Society Conference
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• 2001.05a
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• pp.550.1-550
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• 2001

• Journal of the Optical Society of Korea
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• v.16 no.4
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• pp.336-342
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• 2012

A low-cost optimal double-prism method is proposed by using the developed MATLAB program to correct chromatic aberration. We present an efficient approach to choose a couple of low-cost glasses to obtain a low aberration double prism. The doublet prisms were made of two lead-free glasses. The relative partial dispersion of the two lead-free glasses is identical and their Abbe numbers are different greatly. The proposed design aims to minimize chromatic aberration, such as in apochromats, for paraxial ray tracing. Finally, an optimization design for real ray tracing can be evaluated by the chromatic aberration curve with a minimal area.

• Nuclear Engineering and Technology
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• v.53 no.1
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• pp.208-215
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• 2021

Cosmic-ray muon scattering tomography (MST) technology is a new radiation imaging technology with unique advantages. As the performance of its image reconstruction algorithm has a crucial influence on the imaging quality, researches on this algorithm are of great significance to the development and application of this technology. In this paper, a fast inspection algorithm based on clustering analysis for the identification of the existence of nuclear materials is studied and optimized. Firstly, the principles of MST technology and a binned clustering algorithm were introduced, and then several simulation experiments were carried out using Geant4 toolkit to test the effects of exposure time, algorithm parameter, the size and structure of object on the performance of the algorithm. Based on these, we proposed two optimization methods for the clustering algorithm: the optimization of vertical distance coefficient and the displacement of sub-volumes. Finally, several sets of experiments were designed to validate the optimization effect, and the results showed that these two optimization methods could significantly enhance the distinguishing ability of the algorithm for different materials, help to obtain more details in practical applications, and was therefore of great importance to the development and application of the MST technology.

• Journal of the Korea Safety Management & Science
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• v.6 no.3
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• pp.87-97
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• 2004

The National Health Insurance Act, the Industrial Health Act and the School Health Act require chest radiography at least once a year. In chest radiographic examination, most group examinations use indirect X-ray primarily aiming at diagnosing diseases and enhancing people's health. This study purposed to minimize radiation exposure dose by comparing it between direct and indirect chest X-ray studies. According to the result of comparing and analyzing radiation exposure dose, the average incident dose and penetrating dose were 0.929μGy and 0.179μGy respectively in direct chest X-ray and 6.807μGy and 1.337μGy in indirect chest X-ray In order to minimize radiation exposure dose at direct and indirect chest X-ray, indirect X-ray should be excluded from group examination if possible. Moreover, it is necessary to control the quality of equipment (Q/A & Q/C) systematically and to avoid using unqualified equipment in order to reduce radiation exposure dose.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.992-997
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• 2003

Aspherical lens design method named ray reverse tracing method is introduced. Differently from the traditional design method, the ray reverse tracing method traces the shape and location of a real object by use of its virtual image. From the result, it was convinced that spherical aberration free aspherical lens could be designed by use of the ray reverse tracing method. Furthermore, it could reduce the degree of dependence of optical characteristics on designer's ability, because deformation terms and optimization can be eliminated, which has been performed in conventional lens design process.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.6
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• pp.811-816
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• 2011

We develop a plastic object lens for blu-ray disc playing pick-up module as morethan 0.85 numerical aperture in this research. We design plastic object lens for blu-ray disc playing pick-up module's each factor's in balanced and made our designed lens by injection molding. Furthermore, by correction designing in mold-core, we optimization our lens efficiency as world grade; wave front aberration $0.028{\lambda}$. RMS, light axis differential 0.3967arcmin. We can manufacture localized blu-ray disc's pick-up lens's component and by this fact we obtain international competitiveness. The result of this research will be very helpful to develop a single objective lens for 3 different wavelength of laser diodes in playing and recording pick-up module.

• Journal of the Korea Computer Graphics Society
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• v.11 no.1
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• pp.40-49
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• 2005

Several optimization techniques have been proposed for volume ray casting, but these cannot achieve real-time frame rates. In addition, it is difficult to apply them to some applications that require perspective projection. Recently, hardware-based methods using 3D texture mapping are being used for real-time volume rendering. Although rendering speed approaches real time, the larger volumes require more swapping of volume bricks for the limited texture memory. Also, image quality deteriorates compared with that of conventional volume ray casting. In this paper, we propose a data structure for real-time volume ray casting named PERM (Precomputed dEnsity and gRadient Map). The PERM stores interpolated density and gradient vector for quantized cells. Since the information requiring time-consuming computations is stored in the PERM, our method can ensure interactive frame rates on a consumer PC platform. Our method normally produces high-quality images because it is based on conventional volume ray casting.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.10
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• pp.191-198
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• 2003

In this study, aberration free aspherical lens design method named ray reverse tracing method is introduced. Differently from the traditional design method, the ray reverse tracing method traces the shape and location of a real object by use of its virtual image. From the result, especially spherical aberration free aspherical lens could be designed by use of the ray reverse tracing method. Furthermore, it could reduce the degree of dependence of optical characteristics on designer's ability, because deformation terms and optimization can be eliminated, which has been performed in conventional lens design process.