• Nuclear Engineering and Technology
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• v.52 no.6
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• pp.1271-1276
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• 2020

The geometrical efficiency of a source-to-detector configuration is considered to be necessary in the calculation of the full energy peak efficiency, especially for NaI(Tl) and HPGe gamma-ray spectroscopy detectors. The geometrical efficiency depends on the solid angle subtended by the radioactive sources and the detector surfaces. The present work is basically concerned to establish a new mathematical approach for calculating the solid angle and geometrical efficiency, based on conversion of the geometrical solid angle of a non-axial radioactive point source with respect to a circular surface of the detector to a new equivalent geometry. The equivalent geometry consists of an axial radioactive point source with respect to an arbitrary elliptical surface that lies between the radioactive point source and the circular surface of the detector. This expression was extended to include coaxial radioactive circular disk source. The results were compared with a number of published data to explain how significant this work is in the efficiency calibration procedure for the γ-ray detection systems, especially in case of using isotropic radiating γ-ray sources in the form of point and disk shapes.

• Journal of The Korean Association of Information Education
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• v.22 no.3
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• pp.385-396
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• 2018

This research supports the idea that manipulative devices can be an effective modality tool for learning abstract concepts involved with identifying geometric shapes and enhance learners' problem solving and motivation. Until recently specified manipulative device has been adapted only in traditional classroom environment and it has been very rare to find devices that is designed for online-basis. This study focused on designing and implementing an educational software which guide learners with geoboard in identification and characteristics of polygons. In addition to the function to draw and to delete various shapes, this software helps learners immediately assess the outcome. The results of the Delphi Technique show promising evidence for it being a very efficient means to learn geometric shapes and increase learners' motivation to learn the subject matter.

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.109-109
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• 2002

Purpose： The aim of the study is to see the representation patterns of human visual cortex by perceiving some geometrical shapes. Method： 3 humans as subjects for the fMRI experiment. A classical block or box car design was used as experimental paradigm. 3 different types of fan shapes and concentric circles were presented.

• Wind and Structures
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• v.9 no.2
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• pp.147-158
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• 2006

The purpose of this paper is to find a more accurate method to evaluate pedestrian wind by computational fluid dynamics approach. Previous computational fluid dynamics studies of wind environmental problems were mostly performed by simplified models, which only use simple geometric shapes, such as cubes and cylinders, to represent buildings and structures. However, to have more accurate and complete evaluation results, various shapes of blocking objects, such as trees, should also be taken into consideration. The aerodynamic effects of these various shapes of objects can decrease wind velocity and increase turbulence intensity. Previous studies simply omitted the errors generated from these various shapes of blocking objects. Adding real geometrical trees to the numerical models makes the calculating domain of CFD very complicated due to geometry generation and grid meshing problems. In this case the function of Porous Media Condition can solve the problem by adding trees into numerical models without increasing the mesh grids. The comparison results between numerical and wind tunnel model are close if the parameters of porous media condition are well adjusted.

• Advances in aircraft and spacecraft science
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• v.2 no.1
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• pp.1-16
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• 2015

In this paper, geometrical and mechanical approaches are proposed for the simulation of the draping of woven fabric onto complex parts. The geometrical discrete approach allows to define the ply shapes and fibres orientation in order to optimize the composite structural properties and the continuum meso-structural mechanical approach allows to take into account the mechanical properties of fibres and resin and the various dominating mode of deformation of woven fabrics during the forming process. Some numerical simulations of forming process are proposed and compared with the experimental results in order to demonstrate the efficiency of our approaches.

• Advances in concrete construction
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• v.6 no.3
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• pp.269-283
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• 2018

This study presents the effects of geometrical dimensions of concrete gravity dams on the seismic response considering different base width/dam height (L/H) ratios. In the study, a concrete gravity dam with the height of 200 m is selected and finite element models of the dam are constituted including five different L/H ratios such as 0.25, 0.5, 0.75, 1.00, 1.25. All dams are modeled in ANSYS software considering dam-reservoir-foundation interaction. 1989 Loma Prieta earthquake records are applied to models in upstream-downstream direction and linear time history analyses are performed. Dynamic equilibrium equations of motions obtained from the finite element models of the coupled systems are solved by using Newmark time integration algorithm. The seismic response of the models is evaluated from analyses presenting natural frequencies, mode shapes, displacements and principal stresses. The results show that the L/H ratios considerably affect the seismic response of gravity dams. Also, the model where L/H ratio is 1.00 has more desirable results and most appropriate representation of the seismic response of gravity dams.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.881-886
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• 2012

The paper is facial expression recognition based on the inclined face geometrical information. In facial expression recognition, mouth has a key role in expressing emotions, in this paper the features is mainly based on the shapes of mouth, followed by eyes and eyebrows. This paper makes its efforts to disperse every feature values via the weighting function and proposes method of expression classification with excellent classification effects; the final recognition model has been constructed.

• Fashion & Textile Research Journal
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• v.15 no.3
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• pp.325-335
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• 2013

This work develops a motif design integrated with geometrical patterns in traditional ddeoksal and that can be applied to a scarf design so that traditional elements unique to Korean culture can be developed further for a modern application to various design fields. For the research method, literature reviews on op art and traditional ddeoksal were conducted with Adobe Illustrator CS3 and Adobe Photoshop CS3. As for the motif combination, such applications were taken as five pieces from the works of Victor Vasarely and some traditional ddeoksal shapes such as oblique line pattern, taegeuk pattern, and geometrical pattern. Abstract and geometrical images were borrowed from op art and ddeoksal for image expression. The total number of works selected was eleven. To realize the applied scarf design, a motif layout was performed with the scarf center or rim highlighted so that each design feature could be remarkable based on the motif combination. With the function of scaling, rotation, opacity control, filtering effect, the changed images were shown through motif distortion. In addition, this work applies a single combined motif to products for a possible transformation into handkerchiefs and boutique scarfs in the case of smaller sized scarfs.

• Journal of the Korean Society of Costume
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• v.59 no.4
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• pp.41-53
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• 2009

This study analyzed expression types of dot patterns and derived out inherent characteristics to provide fundamental resources for advancement of high value added creative designs. As a result of the study, Firstly, the circular motive was used to form silhouettes or as a symbol of a decoration. Secondly, a simple form and color dot pattern was used to create one side, or a circular shaped accessory was used to be recognized as a construction line or a decoration line. Thirdly, textile printing is mainly used but handicraft and decorative images were used to add vitality through piece technique, embroidery, collage, cut-out, patch work, etc. Fourthly, different circular motives were integrated, partitioned and duplicated for abstract geometrical images. Fifthly, variations were added by mixing different dot patterns that are arranged regularly and irregularly in different sizes and gaps creating compounded designs with handicraft touches, different angles or on top of each other. Sixthly, hybrid images were created with rearrangement of dot patterns and by adding floral shapes, stripes or other abstract and geometrical shapes. Such various and creative attempts construct new formative beauty in fashion design and I believe that it can establish the development of unique images that satisfies the taste of today's consumers.

• Journal of Ocean Engineering and Technology
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• v.26 no.2
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• pp.26-32
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• 2012

In this paper, the effects of irregular bead shapes on fatigue life were investigated. A modified S-N curve method was used to estimate the fatigue life, which considered the inherent multiaxiality caused by the geometrical feature produced by the welding process. The point method of the critical distance method was used to determine the fatigue effective stress. Three types of fillet joint models were tested in the fatigue experiments. For each model, real bead shapes were collected using a 3D laser scanner, and finite element analyses were performed. The results of the analyses with actual bead shapes were compared with those using an idealized bead shape model. The results of the present analytical methods showed good agreement with the experimental results.