• Journal of Elementary Mathematics Education in Korea
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• v.20 no.3
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• pp.393-406
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• 2016

In the sixth grade mathematics, drawing of development figures of the triangular prism and the quadrangular prism is recommended in terms of the creativity. In this sense, the teacher has the need to check in advance all the possible development figures of the triangular prism and the quadrangular prism before teaching on them. However, previous studies that currently give all the possible development figures of the triangular prism and the quadrangular prism are hard to find. For this reason, in this paper, as a study of teaching materials for the professional development of elementary school teachers, the method of finding all the possible development figures of the triangular prism and all the possible development figures of the quadrangular prism without omissions and overlaps and the number of each of development figures which can be obtained by that method are discussed. Here lengths of the three sides of base planes of the triangular prism are different each other and lengths of the four sides of base planes of the quadrangular prism are different each other. This discussion is needed in terms of a study of teaching materials in order to prepare for predictable questions to ask the number of the possible development figures of the triangular prism and the number of the possible development figures of the quadrangular prism in classes. In addition, through this discussion, this paper presents the development figures of the triangular prism and the development figures of the quadrangular prism without omissions and overlaps. And teachers can take advantage of them for determining the correctness of the development figures drew by students and guiding students to draw the development figures creatively in actual classes.

• Journal of the Korea Concrete Institute
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• v.28 no.1
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• pp.75-84
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• 2016

The purpose of this study was to investigate the performance of solid reinforced concrete columns with triangular reinforcement details. The proposed reinforcement details has economic feasibility and rationality and makes construction periods shorter. A model of solid reinforced concrete columns with triangular reinforcement details was tested under a constant axial load and a quasi-static, cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. The used numerical method gives a realistic prediction of performance throughout the loading cycles for several test specimens investigated. As a result, proposed triangular reinforcement details for material quantity reduction was superior to existing reinforcement details in terms of required performance.

• Geophysics and Geophysical Exploration
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• v.13 no.2
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• pp.169-174
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• 2010

We developed a precise terrain correction program using triangular element method (TEM) for microgravity data processing. TEM calculates gravity attraction of arbitrary polyhedra whose surface is patched by triangles. We showed that TEM can calculate more precise terrain effect than conventional rectangular prism method. We tested the accuracy of TEM on the cone model which has analytic solution. Also, we tested the accuracy of TEM on the slope model, this results showed that there are big differences calculated by TEM and rectangular prsim method (RPM) on slope model. The developed terrain correction program was applied on the gravity data on the southern area near sea shore of Korean peninsula, calculated terrain effect very precisely.

• Proceedings of the KSRS Conference
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• 2008.03a
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• pp.219-223
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• 2008

초분광 영상은 기존의 다중분광 영상보다 많은 파장대의 영상을 취득하기 때문에 다양한 분야의 연구에 이용되고 있다. 하지만 밴드별로 취득하는 파장대가 짧고 밴드수가 많아, 밴드간의 높은 상관관계 및 노이즈 밴드가 존재한다. 이로 인해 기존에 알려진 분석기법의 적용결과가 제대로 도출되지 않는다. 따라서 초분광 영상을 이용할 경우, 노이즈가 많이 포함된 밴드를 제거한 후 영상분석을 하는 것이 보다 효율적이다. 본 연구에서는 초분광 영상(Hyperspectral Image)의 전처리 과정 중 노이즈 밴드 제거에 초점을 맞추었으며, 이를 위해 프랙탈 차원을 이용하였다. 프랙탈 차원 측정방법 중 삼각기둥 표면적 기법을 이용하였다. 프랙탈 차원을 측정하고, Continuum Removal 기법을 이용하여 경향을 살펴보았다. 경험적으로 구한 임계값을 통해 상대적으로 정보량이 적은 밴드를 노이즈 밴드로 판단하여 제거하였다. 실험 영상으로는 EO-1 위성에서 취득되는 Hyperion 초분광 영상을 사용하였다. 실험 결과 프랙탈 분석을 통해 Hyperion 초분광 영상의 노이즈 밴드를 자동으로 추출하여 제거할 수 있음을 확인하였다.

• Transactions of the Korean Society of Mechanical Engineers
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• v.13 no.1
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• pp.59-66
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• 1989

The purpose of this study is to develop a personal computer aided 3-D geometric modeller. To perform this study, we set up a cube, cylinder, and a prism as primitives in the first segment of this study. By modelling the 3-D object through their transformation, addition, and subtraction, we proved the validity of the developed algorithm and its computer program. Some examples show the results of applying the program to model a few simple shapes of the machine parts. These results met the first aim of this study.

• Journal of the Korean Institute of Gas
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• v.17 no.1
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• pp.13-18
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• 2013

Experimental studies were carried out to investigate the interactions between the propagating flame fronts and different multiple obstacles within an explosion chamber. The explosion chamber is 600 mm in height, $700{\times}700mm^2$ in cross-section and has a H/L value of 0.86. Three different multiple obstacles with the blockage ratio of 0.43 were replaced within the chamber. The results showed that relatively higher local flame displacement speed was observed with the triangular obstacle while the lower was observed with the circular one. It was found that the local flame displacement speeds behind the obstacle were largely dependent on the obstacle types. It was also found that as the flame interacted with the flow field generated behind the obstacle, the probability density functions(PDFs) of the local flame displacement speed were extensively distributed toward higher speeds.

• Journal of the Korean Institute of Gas
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• v.12 no.3
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• pp.68-74
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• 2008

Measurements were performed to investigate the effects on flame and pressure development by varying locations of multiple obstacles in a top-venting explosion chamber. The chamber dimension was 1000 mm in height with a $700\;{\times}\;700\;mm^2$ cross-section and a rectangular vent area of $700\;{\times}\;700\;mm^2$. Three different multiple obstacles with blockage ratio of 30% were used by changing from 200 mm, 500 mm to 800 mm in heights within the chamber. Temporally resolved flame front images were recorded by a high speed camera to investigate the interaction between the propagating flame and the obstacles. The results showed that the triangular bar caused the fastest flame developments at given times whereas the lowest was obtained with the cylindrical bar. It was also found that local flame displacement speeds of different obstacles were sensitive to the locations of obstacles. The local speed becomes larger in going from 200 mm, to 500 mm and to 800 mm in heights. The obstacles in height of 800 mm yielded the highest overpressure whereas the lowest was in height of 200 mm.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1454-1456
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• 2003

전기절연재로서의 성능이 우수하며, 다른 물질과의 결합 및 성형의 편리성 및 경량화에 부합할 수 있는 실리콘 고무의 사용이 급증하고 있다. 이에 본 논문에서는 현수애자에 사용중인 실리콘 고무를 선택하여 제조시에 발생할 수 있는 내부보이드에 대한 전기적특성을 알아보기 위해 실리콘 고무를 3층으로 적층하여 중간층 중심에 비슷한 체적으로 인공보이드를 원통 및 삼각기등형의 보이드를 제작하여 보이드형상 변화에 따른 부분방전전하량을 측정하였다. 위상(${\Phi}$)-전하량(q)-빈도(n)에 대한 데이터를 3차원그래프로 나타냈으며, 또한 평균방전전류 및 방전전력 변화를 통한 보이드 결함 특성을 파악하였다. 그 결과, 전압인가 시간에 따라 원통보이드의 경우 초기에는 방전전류 및 방전전력이 증가 하다가 일정시간이 경과하면 감소하는 형태를 나타냈으며, 삼각기둥보이드의 경우 계속적으로 증가하는 모습을 보여주었다.

• Progress in Medical Physics
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• v.19 no.4
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• pp.227-230
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• 2008

The purpose of this study was to design and construct an ultrasound phantom for volume calibration and evaluate the volume measurement accuracy of a 2 dimensional ultrasonic system. Ultrasound phantom was designed, constructed and tested. The phantom consisted of a background material and a target. The background was made by mixing agarose gel with water. A target, made with an elastic material, was filled with water to vary its volume and shape and inserted into background material. To evaluate accuracy of a 2 dimensional ultrasonic system (128XP, ACUSON), three different shapes of targets (a sphere, 2 ellipsoids and a triangular prism) were constructed. In case of ellipsoid shape, two targets, one with same size length and width (ellipsoid 1) and another with the length 2 times longer than width (ellipsoid 2) were examined. The target volumes of each shape were varied from 94cc to 450cc and measurement accuracy was examined. The volume difference between the real and measured target of the sphere shape ranged between 6.7 and 11%. For the ellipsoid targets, the differences ranged from 9.2 to 10.5% with ellipsoid 1 and 25.7% with ellipsoid 2. The volume difference of the triangular prism target ranged between 20.8 and 35%. An easy and simple method of constructing an ultrasound phantom was introduced and it was possible to check the volume measurement accuracy of an ultrasound system.

• Journal of Korean Society of Steel Construction
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• v.29 no.1
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• pp.25-36
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• 2017

In the 1994 Northridge earthquake, connection damage initiated from the beam bottom flange was prevalent. The presence of a concrete slab and resulting composite action was speculated as one of the critical causes of the prevalent bottom flange fracture. In this study, four seismic retrofit schemes are proposed in order to salvage welded steel moment connections with composite floor slabs in existing steel moment frames. Because top flange modification of existing beams is not feasible due to the presence of a concrete floor slab, three schemes of bottom flange modification by using welded triangular or straight haunches or RBS(reduced beam section), and beam web strengthening by attaching heavy shear tab were cyclically tested and analyzed. Test results of this study show that haunch and web-strengthened specimens can eliminate the detrimental effect caused by composite action and ensure excellent connection plastic rotation exceeding 5% rad. Design recommendations for each retrofit scheme together with supplemental numerical studies are also presented.