• Journal of Educational Research in Mathematics
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• v.13 no.4
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• pp.463-483
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• 2003

In the learning of mathematics, students experience the semiotic activities of representing and interpreting mathematical signs. We called these activities as the representing and interpreting of mathematical signs. On the foundation of Peirce's three elements of the sign, we analysed that students constructed the representamen to interpret the concept of correlation as for the object, "as one is taller, one's size of foot is larger" 4 middle school students who participated the gifted center in Seoul, arranged the statistical data, constructed their own representamen, and then learned the conventional signs as a result of the whole class discussion. In the process, students performed the detailed representing and interpreting of signs, depended on the templates of the known signs, and interpreted the process voluntarily. As the semiotic activities were taken place in this way, it was needed that mathematics teacher guided the representing and interpreting of mathematical signs so that the representation and the meaning of the sign were constructed each other, and that students endeavored to get the negotiation of the interpretants and the representamens, and to reach the conventional representing.

• Journal of the Korea Computer Graphics Society
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• v.11 no.1
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• pp.31-39
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• 2005

음함수 표면을 이용한 모델링 방법은 부드러운 곡면을 나타내기에 적합하며 날카로운 부분을 표현하기 위해서는 CSG 연산을 적용한다. 기존의 방식을 이용해서 얻은 매쉬에서는 흔히 음함수의 표면과 상당한 오차를 가지는 매쉬 첨점(vertex)을 얻거나 겹쳐지는 삼각형 또는 날카로운 부분의 표현이 안 되는 점 등의 문제가 나타난다. 본 논문에서는 타원체의 특성을 이용해서 타원체 기반 음함수 표면을 정확하게 샘플링하고 동시에 날카로운 부분을 효과적으로 표현할 수 있는 매쉬를 얻기 위한 폴리곤화 방법을 제안한다. 이러한 목표를 위해 타원체의 투사 특성과 표면 법선 벡터의 연속 특성을 이용해서 음함수 표면 위에 정확하게 위치하는 첨점(vertex)의 위치를 찾고 날카로운 부분을 효과적으로 표현하기 위해 점진적인 방법으로 정확한 첨점(vertex) 위치를 찾는 방법을 제안한다. 지금까지 약점으로 지적되어 왔던 음함수 표면 모델링의 시각화 절차를 이 방법을 통해 개선함으로써 음함수 표면 모델링 기법이 제공하는 다른 장점들을 적극 활용할 수 있을 것으로 기대한다.

• Journal of Korea Game Society
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• v.14 no.6
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• pp.49-58
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• 2014

In particle-based fluid simulation, the yield stress is required for the deformation of the viscoelastic material like gel. von Mises's yield condition has been proposed to implement deformation of viscoelastic objects, but did not express the explosion. Furthermore, von Mises's yield condition is hard to approximate. We propose an ideal yield condition for viscoelastic object that reference from Tresca's yield condition. Unlike conventional particle-based simulation approximate the external power by the deformed length of the object, this paper is approximate the external power by area of the object. We check up that explosion was realistic when a viscoelastic object is compressed under the ideal yield condition.

• IE interfaces
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• v.8 no.3
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• pp.141-153
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• 1995

기존의 솔리드 모델링 시스템은 형상 표현에 있어서의 제약성과 통합 시스템으로서의 폐쇄성으로 인하여 응용 범위에 제약이 따른다. 이러한 약점을 극복하고자 하는 노력의 일환으로서, 최근에 등장한 것이 비다양체 모델을 지원하는 CAD 시스템 커널이다. 본 논문에서는 이러한 비다양체 모델을 지원할 수 있는 모델링 커널 시스템 개발의 기초가 되는 비다양체 자료구조와 이것을 바탕으로 한 오일러 공식 및 오일러 작업에 대해 소개한다. 그리고 이러한 오일러 작업을 실제로 구현하여 모델링 작업을 수행해 봄으로써, 본 논문에서는 제안된 비다양체 자료구조와 오일러 작업의 유용성을 보인다.

• The Journal of the Korea institute of electronic communication sciences
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• v.8 no.8
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• pp.1207-1212
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• 2013

Arithmetic operations over finite fields are widely used in coding theory and cryptography. In both of these applications, there is a need to design low complexity finite field arithmetic units. The complexity of such a unit largely depends on how the field elements are represented. Among them, representation of elements using a optimal normal basis is quite attractive. Using an algorithm minimizing the number of 1's of multiplication matrix, in this paper, we propose a multiplier which is time and area efficient over finite fields with optimal normal basis.

• Communications of Mathematical Education
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• v.19 no.3 s.23
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• pp.517-526
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• 2005

본 연구에서는 사면체의 부피를 구하는 두 가지 공식을 다룰 것이며, 이들은 외형적으로 또는 계산 방법상으로 삼각형의 넓이를 구하는 헤론의 공식과 유사하다. 이들 중에서 하나는 사면체의 모서리와 평면각들을 이용하여 사면체의 부피를 표현하며, 다른 하나는 사면체의 모서리들만 이용하여 부피를 표현한 것으로 2002년에 미해결 탐구 문제로 제시된 바 있다. 본 연구에서는 헤론 공식과 이들 두 공식의 유사점에 대해 논의하며, 모서리들만을 이용하여 부피를 구하는 공식에 대한 새로운 기초적인 증명 방법을 제시할 것이다.

• Journal of Korea Society of Industrial Information Systems
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• v.24 no.4
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• pp.1-8
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• 2019

Plant phenomics is a technique for observing and analyzing morphological features in order to select plant varieties of excellent traits. The conventional methods is difficult to apply to the phenomics system. because the color threshold value must be manually changed according to the detection target. In this paper, we propose the convolution neural network (CNN) structure that can automatically segment plants from the background for the phenomics system. The LeafNet consists of nine convolution layers and a sigmoid activation function for determining the presence of plants. As a result of the learning using the LeafNet, we obtained a precision of 98.0% and a recall rate of 90.3% for the plant seedlings images. This confirms the applicability of the phenomics system.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.366-374
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• 2014

The study was conducted to investigate the possibility that epigenetic DNA methylation causes tree phenotypic variation in autotetraploids through evaluating the phenotypic variation and DNA methylation in autotetraploids occurred spontaneously from diploid trifoliate orange. Chromosome analysis confirmed that fourteen trifoliate orange trees of selected by flow cytometry were tetraploids (2n = 4X = 36) without any aneuploids. Chromomycin A3 staining determined that these trees were all autotetraploid with doubled chromosome set. Tree phenotypes, such as tree height and width, branching number, length, and angle, internode length, and leaf characteristics, varied in the autotetraploids. Chlorophyll indices were diverse in the autotetraploids, but photosynthetic rates were not significantly different. In addition, a wide range of variation was observed in stomatal density and guard cell length. Analysis of global cytosine DNA methylation showed that there was a variation of the methylation level in autotetraploids. More than half of 14 autotetraploids had at least 2 times higher methylation level than diploid trifoliate orange. The results indicate that tree phenotypic variation in autotetraploids might be related to global DNA methylation for reducing gene redundancy.

• Journal of the Society of Naval Architects of Korea
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• v.32 no.2
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• pp.1-9
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• 1995

This paper suggests a numerical method that creates and varies hull form geometry of underwater vehicle. That is, it induces the cylindrical underwater vehicle from principal dimensions-total length, the length of parallel middle body, the coefficient defining entrance & run parts etc.-and represents using NURBS curve. Also, each section of hull form is varied by user interface and Sectional Area Curve is generated.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.13 no.1
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• pp.101-105
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• 2002

In this paper, the coupling windows of the dielectric resonator filter have been analyzed. The coupling factor which has been used to characterize the coupling window is represented by closed form expressions. The deviation of the coupling factor as the size of coupling window has been compared between calculated by presented method and measured ones. There are very closed agreements. The presented method can be applied not only to design dielectric resonator but also to design varactor tuned dielectric resonator filter so as that the passband bandwidth is constant within tuned ranges.