• East Asian mathematical journal
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• 제33권2호
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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.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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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.

• 대한금속재료학회지
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• 제46권4호
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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.

• 건축역사연구
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• 제1권1호
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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.

• 한국정보통신학회논문지
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• 제6권5호
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• pp.789-795
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• 2002

컬러 이미지는 Gray Scale 이미지와는 달리 3가지 채널의 조합으로 이루어지고 방대한 정보량 때문에 효과적인 이미지 분할이 어렵다. 본 논문에서는 범용성 있는 Color Morphological Pyramids(CMP)구조를 제안하고, 그를 이용한 이미지 분할을 보인다. 이미지 피라미드 구조는 최초 이미지의 반복적인 필터링과 샘플링에 의해 면적비가 $2^{\int}({\int}=1,2,....,N)$이 되는 순차적 이미지 계열이다. 본 방법에서는 CMP를 이용하여 RGB, HSI, CMY 등의 컬러 공간에서 연속적인 필터링 처리로 불필요한 크기의 물체 및 잡음을 제거하고, 다운샘플링과정으로 해상도를 낮춰준다. 생성된 CMP에서 인접 레벨 이미지간에는 이웃한 픽셀 벡터간의 상대거리를 이용한 연결식을 사용하여 새 레벨의 이미지를 생성한 후 이를 이미지 분할한다. 이미지 분할실험을 통하여 본 방법의 유효성을 검증한다.

• 대한금속재료학회지
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• 제46권12호
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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.

• 한국재료학회지
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• 제19권1호
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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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• 제42권3호
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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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• 제15권2호
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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.

• 한국학교수학회논문집
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• 제20권1호
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• pp.43-56
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• 2017

본 논문에서는 2009 개정 초등학교 수학과 교육과정에 따른 $\ll$2009 수학 6-1${\gg}$에서 제시하고 있는 각뿔의 외연을 고찰하고 있다. $\ll$2009 수학 6-1${\gg}$에서는 전형적인 각뿔의 겨냥도를 예시하는 외연적 정의 방법을 사용해서 각뿔을 정의하고 있다. $\ll$2009 수학 6-1 교사용 지도서${\gg}$에서는 빗각뿔을 취급할 수밖에 없다고 말하고 있지만, $\ll$2009 수학 6-1${\gg}$에서 예시하고 있는 각뿔의 겨냥도로 보면, 빗각뿔 그리고 밑면의 모양이 정다각형이 아닌 직각뿔이라고 볼 수 있는 것은 사실상 나타나고 있지 않다. 본 논문에서는 이러한 결과를 바탕으로, 다음의 시사점을 결론으로 제시한다. 첫째, 초등학교 수학에서의 각뿔의 외연에 대한 논의와 그 결과에 대한 동의가 충분히 있어야 한다. 둘째, 교육과정의 의도가 교사용 지도서를 거쳐 교과서에서 구현되는 과정에서 각뿔의 외연이 일관되어야 한다. 셋째, 각뿔과 관련해서 초등교사가 알아야 할 지식에 관해 어느 정도 합의가 있어야 한다.