• East Asian mathematical journal
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• v.33 no.2
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• pp.149-175
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• 2017

The effort to find the volume of pyramids has been done by mathematicians for a long time, and many trial-and-error calculations and proofs give various perspectives and educational material. In the early days, finding the volume of pyramids was mainly studied by calculating the volume of triangular pyramids or quadrangular pyramids by cutting and the relationship between pyramids. Thereafter, methods based on infinite, infinitesimal, limit, etc. appeared, but the research topic was still about them. The purpose of this study is to examine the four themes appearing the mathematics history in terms of methodology, and to think about its implications from the viewpoint of improving the professionalism of the teachers.

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.100.2-100.2
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• 2012

Surface texturing of crystalline silicon is carried out in alkaline solutions for anisotropic etching that leads to random pyramids of about $10{\mu}m$ in size. Recently textured pyramids size gradually reduced using new solution. In this paper, we investigated that texture pyramids size had an impact on emitter property and front electrode (Ag) contact. To make small (${\sim}3{\mu}m$) and large (${\sim}10{\mu}m$) pyramids size, texturing times control and one side texturing using a silicon nitride film were carried out. Then formation and quality of POCl3-diffused n+ emitter in furnace compare with small and large pyramids by using SEM images, simulation (SILVACO, Athena module) and emitter saturation current density (J0e). After metallization, Ag contact resistance was measured by transfer length method (TLM) pattern. And surface distributions of Ag crystallites were observed by SEM images. Also, performance of cell which is fabricated by screen-printed solar cells is compared by light I-V.

• Korean Journal of Metals and Materials
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• v.46 no.4
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• pp.217-222
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• 2008

Characteristics of etching and induced surface morphology variation by wet-etching of n-face n-type GaN were investigated using KOH solutions. It was observed that hexagonal pyramids were formed on the etched surface regardless of etching conditions. However, the size of the hexagonal pyramids was changed as the etching time and temperature increased, respectively. Initially, as the etching time and concentration of KOH solution increased, the hexagonal pyramid was observed to be dissociated into smaller pyramids. However, as the etching time increased further, the size of the hexagonal pyramids increased again, indicating that the etching of N-face n-type GaN by KOH solutions proceeded through the evolution of hexagonal pyramids, such as formation, dissociation and enlargement of pyramids. Furthermore, it was also observed that there is a correlation between the photoluminescence intensity of the etched surface and the value of root-mean-square roughness. The intensity of PL increased as the roughness value increased due to the enhancement of the extraction efficiency of the generated photons.

• Journal of architectural history
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• v.1 no.1 s.1
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• pp.205-217
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• 1992

For all the variety of past studies on the pyramids of Old Kingdom of Egypt, they still basically remain in 'enigma and mystery' as Giedion rightly puts in. This paper deals directly with the three most obvious facts about the pyramids : their cardinal orientation, the varying slopes, and above all, their magnitude. The prominent triangles of their once polished faces were there to be seen from the Nile valley as they shined or shaded under the Sun. The northern faces, especially, went in and out of the Sun in accordence with the seasonal variation of the solar declination, The steeper northern faces which turned into shade in high summer noon could have been warning signs of oncoming inundation of Nile, and the milder slopes that suddenly began to shine in some early spring noons could have been the vernal alarms to awaken the peasants to their timely toil on the fresh land. Dates and hours of insolation on the northern faces of pyramids are graphically and numerically computed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.5
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• pp.789-795
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• 2002

Color image is formed of combination of three color channels. Therefore its architecture is very complicated and it requires complicated image Processing for effective image segmentation. In this paper. we propose architecture of universalized Color Morphological Pyramids(CMP) which is able to give effective image segmentation. Image Pyramid architecture is a successive Image sequence whose area ratio $2^{\int}({\int}=1,2,....,N)$ after filtering and subsampling of input image. In this technique, noise removed by sequential filtering and resolution is degraded by downsampling using CMP in various color spaces. After that, new level images are constructed that apply formula using distance of neighbor vectors in close level images and segments its image. The feasibility of proposed method is examined by comparing with the results obtained from the existing method.

• Korean Journal of Metals and Materials
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• v.46 no.12
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• pp.835-840
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• 2008

Texturing for crystalline silicon solar cells is one of the important techniques to increase conversion efficiency by effective photon trapping. Generally, incoming wafers or alkali etched wafers are used for texturing. From this conventional etching process, $7{\sim}10{\mu}m$-sized random pyramids are formed. In this study, acid etching for removal of saw damages was practiced before texturing. This improved the resulting surface morphology, which consisted of $2{\sim}4{\mu}m$-sized pyramids. Because these pyramids covered the surface much more extensively, we obtained reduction of optical losses on the surface. In order to compare with conventional texturing, FE-SEM is used for observing surface morphology and reflectance data is analyzed by UV-VIS spectrophotometer.

• Korean Journal of Materials Research
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• v.19 no.1
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• pp.18-23
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• 2009

The influence of various surface morphologies on the mechanical strength of silicon substrates was investigated in this study. The yield for the solar cell industry is mainly related to the fracturing of silicon wafers during the manufacturing process. The flexural strengths of silicon substrates were influenced by the density of the pyramids as well as by the size and the rounded surface of the pyramids. To characterize and optimize the relevant texturing process in terms of mechanical stability and the fabrication yield, the mechanical properties of textured silicon substrates were investigated to optimize the size and morphology of random pyramids. Several types of silicon substrates were studied, including the planar type, a textured surface with large and small pyramids, and a textured surface with rounded pyramids. The surface morphology and a cross-section of the as-textured and fractured silicon substrates were investigated by scanning electron microscopy.

• Applied Microscopy
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• v.42 no.3
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• pp.151-157
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• 2012

The microstructure of various shapes of stacking fault pyramids (SFPs) formed in multiple implant/anneal Separation by Implanted Oxygen (SIMOX) material were investigated by plan-view and cross-sectional transmission electron microscopy. In the multiple implant/anneal SIMOX, the defects in the top silicon layer are confined at the interface of the buried oxide layer at a density of ${\sim}10^6\;cm^{-2}$. The dominant defects are perfect and imperfect SFPs. The perfect SFPs were formed by the expansion and interaction of four dissociated dislocations on the {111} pyramidal planes. The imperfect SFPs show various shapes of SFPs, including I-, L-, and Y-shapes. The shape of imperfect SFPs may depend on the number of dissociated dislocations bounded to the top of the pyramid and the interaction of Shockley partial dislocations at each edge of {111} pyramidal planes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.786-799
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• 2021

Road damage detection is important for road maintenance. With the development of deep learning, more and more road damage detection methods have been proposed, such as Fast R-CNN, Faster R-CNN, Mask R-CNN and RetinaNet. However, because shallow and deep layers cannot be extracted at the same time, the existing methods do not perform well in detecting objects with fewer samples. In addition, these methods cannot obtain a highly accurate detecting bounding box. This paper presents a Multi-level Feature Pyramids method based on M2det. Because the feature layer has multi-scale and multi-level architecture, the feature layer containing more information and obvious features can be extracted. Moreover, an attention mechanism is used to improve the accuracy of local boundary boxes in the dataset. Experimental results show that the proposed method is better than the current state-of-the-art methods.

• Journal of the Korean School Mathematics Society
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• v.20 no.1
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• pp.43-56
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• 2017

In this thesis, the extension of the pyramid is contemplated through the pyramids presented in textbook $\ll$Math 6-1${\gg}$ published according to the 2009 revised curriculum. In textbook $\ll$Math 6-1${\gg}$, the pyramid is defined by presenting rough sketches of typical pyramids in an extensional definition method. This contrasts with the method of defining the pyramid by using such an extensional definition and a connotative definition method that reveals common properties of all pyramids. In textbook $\ll$Math 6-1${\gg}$, right pyramids whose base can not be regarded as regular polygons, and oblique pyramids are hardly presented. Nonetheless, $\ll$Math 6-1 Teacher's Guide Book${\gg}$ says that we have no choice but to handle oblique pyramids. In this thesis, based on these results, the following implications are presented as conclusions. First, there should be enough discussion on the extension of the pyramid in elementary school mathematics, and agreement to the results. In particular, such discussions are highly necessary in revising the curriculum. Second, in the process of realizing the intention of the curriculum in the textbook through the teacher's guidebook, the extension of the pyramid must be consistent. Third, there should be some consensus about the knowledge that elementary teachers should know about the pyramid.