• Korean Journal of Optics and Photonics
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• v.7 no.4
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• pp.333-340
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• 1996

We have implemented a planar integrated optics for the fractional Fourier transform (FRT) which has recently been developed as a generalized form of the conventional Fourier transform. FRT optical systems provide versatile tools for analyzing signals and designing hardwares, but require high accuracy and stability in the arrangement of optical components because of their shift-variant characteristic. The planar optical FRT setup composed of free-space optical components integrated on a single glass block makes the FRT of 2-dimensional(2-D) input patterns through the 3-D glass-space. Therefore, taking advantage of the compactness, easy alignment and thermal/mechanical stability, the planar optics can provide a useful approach to realizing an optical fractional correlation system in a practical way. In the experiment, we have obtained accurate FRT results by using the planar integrated optics with 4 different fractional orders of 0.25, 0.5, 0.75, and 1.0.

• 한국HCI학회:학술대회논문집
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• 2007.02b
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• pp.153-158
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• 2007

기존의 모바일 기기들은 일반화된 고정 인터페이스 상태의 제품으로, 사용자가 단순 학습을 통해 반복된 인터렉션과 구성만을 이용하는 수준이었으나 최근과 같이 기기가 지능적이고 다양화되면서 개인의 요구와 특성을 반영한 인터페이스 방법들을 요구하기 시작하였다. 이에 따라 일반적 성향에 맞추어진 Universal UI와 개인의 특성에 맞춰진 Customizing UI의 양립적 이슈는 지속적으로 대치되어 왔다. 그러므로 이를 서로 적절한 수준에서 상호 보완하여 디자인하는 것은 그 형태나 속성을 떠나 최신 UI의 기본적인 필요충분조건이 되었다. Universal UI는 인식과 행동패턴을 달리하는 사람들의 공통분모를 찾아냄으로써 표준화의 Solution을 찾아낼 수 있었지만 Customizing에 대한 해답은 사용자 심리, 문화, 역사까지 고려해야 한다. 우리는 이 두 부분을 모두 만족하는 다방면의 멘탈모델 수립과 UT검증을 통해 모바일 기기에서 최적의 인터페이스 개발을 진행하게 되었다. 이러한 Customizing에 대한 연구는 기기 사용자의 지역과, 문화적 특성에 따라 최적화된 인터페이스를 제공할 수 있기에 기기 제조사는 Future work을 위해서라도 이러한 부분에의 충분한 연구 의의가 있다고 할 수 있다. 우리는 본 논문에서와 같은 Personalization과, 선호 기능을 좀 더 쉽게 적응하고 사용할 수 있도록 하는 Customization 을 통해 사용자의 성향을 적극 반영할 수 있는 모바일 인터페이스 제품 개발로 한 단계 발전시켰다고 본다.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.1
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• pp.65-80
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• 2010

The aims of our study are to investigate the nature of mathematical reasoning and the teaching of mathematical reasoning in school mathematics. We analysed the process of shaping deduction in ancient Greek based on Netz's study, and discussed on the comparison between his study and Freudenthal's local organization. The result of our analysis shows that mathematical reasoning in elementary school has to be based on children's natural language and their intuitions, and then the mathematical necessity has to be formed. And we discussed on the sequences and implications of teaching of the sum of interior angles of polygon composed the discovery by induction, justification by intuition and logical reasoning, and generalization toward polygons.

• Bulletin of the Korean Space Science Society
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• 2009.10a
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• pp.39.3-39.3
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• 2009

우주기상현상에서 자기폭풍은 태양으로부터 태양풍, 지구 자기권, 고층대기를 모두 포함하는 매우 복잡한 현상인데, 이들 중 자기폭풍이 고층대기 이온권에 미치는 영향에서도 매우 복잡하고 다양한 모습으로 나타난다. 자기폭풍이 이온권에 미치는 영향의 연구는 대부분 어떤 특정한 자기폭풍이 일어났을 때 이온권에 나타나는 변화의 관측자료 분석이나 모델링을 통한 연구이다. 그러나 이러한 연구는 자기폭풍이 일어나면 보통 이온권에는 어떤 변화가 일어나는지에 대한 답을 주지는 못한다. 한편, 이온권은 시간, 위치, 태양 및 지자기 활동 등의 변화에 따라 일반적인 변화경향을 보일 수 있는데, 이러한 물리적 조건 중 지자기활동이 변화할 때, 즉 자기폭풍이 발생할 때 이온권이 어떤 변화를 보이는지에 대한 일반적인 경향은 아직 정확히 알려져 있지 않다. 이는 자기폭풍의 영향이 다양한 조건에서 대단히 복잡한 패턴을 가지고 있어 간단히 일반화하기 어렵기 때문인데, 장기간의 이온권 관측 자료를 이용하여 체계적인 분석을 통해 자기폭풍이 얼어났을 때 공통으로 나타나는 이온권 변화를 연구할 수 있을 것으로 기대된다. 최근 인공위성을 이용하여 장기간에 걸쳐 전지구적인 이온권 관측이 수행되고 있는데, GPS나 TOPEX/JASON 위성 등에서 이온권 총 전자량이 관측되고 있다. 향후 이러한 관측 자료의 체계적인 분석을 통해 자기폭풍에 의한 이온권 변화의 일반적인 경향을 체계화 할 수 있을 것으로 기대된다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.12
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• pp.2418-2425
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• 1994

Although the error backpropagation(EBP) algorithm based on the gradient descent method is a widely-used learning algorithm of neural networks, learning sometimes takes a long time to acquire accuracy. This paper develops a novel learning method to alleviate the problems of EBP algorithm such as local minima, slow speed, and size of structure and thus to improve performance by adopting other new networks. Gaussian Potential Function networks(GPFN), in parallel with multilayer neural networks. Empirical simulations show the efficacy of the proposed algorithm in function approximation, which enables us to train networks faster with the better generalization capabilities.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.21 no.2
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• pp.103-109
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• 2021

About the orthogonal Hadamard matrix announced by Hadamard in France in 1893, Professor Moon Ho Lee newly defined it as Center Weight Hadamard in 1989 and announced it, and discovered the Jacket matrix in 1998. The Jacket matrix is a generalization of the Hadamard matrix. In this paper, we propose a method of obtaining the Symmetric Jacket matrix, analyzing important properties and patterns, and obtaining the Jacket matrix's determinant and Eigenvalue, and proved it using Eigen decomposition. These calculations are useful for signal processing and orthogonal code design. To analyze the matrix system, compare it with DFT, DCT, Hadamard, and Jacket matrix. In the symmetric matrix of Galois Field, the element-wise inverse relationship of the Jacket matrix was mathematically proved and the orthogonal property AB=I relationship was derived.

• Education of Primary School Mathematics
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• v.26 no.4
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• pp.257-275
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• 2023

In this study, we designed and implemented a instruction emphasizing mathematical argument for fifth-grade students and analyzed the teaching practices. Through a literature review related to instruction emphasizing mathematical argument, we organized a teaching model of five phases that explain why the general claim that the sum of consecutive odd numbers equals a square number is true: 1) noticing patterns, 2) articulating conjectures, 3) representing through visual model, 4) arguing based on representation, 5) comparing and contrasting. Then, we analyzed the argumentation stream by phases to observe how the instruction emphasizing mathematical argument is implemented in the elementary classroom. Based on the results of this study, we discuss the implications of teaching a mathematical argument in elementary school.

• East Asian mathematical journal
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• v.40 no.2
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• pp.209-229
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• 2024

In this study, we design a teaching unit that constructs Pascal graphs and extended Pascal triangles to explore number patterns inherent in them. This teaching unit is designed to consider the diachronic process of teaching-learning by combining Dörfler's theoretical generalization model with Wittmann's design science ideas, which are applied to the didactical practice of mathematization. In the teaching unit, considering the teaching-learning level of prospective teachers who studied discrete mathematics, we generalize the well-known Pascal triangle and its number patterns to extended Pascal triangles which have directed graphs(called Pascal graphs) as geometric models. In this process, the use of symbols and the introduction of variables are exhibited as important means of generalization. It provides practical experiences of mathematization to prospective teachers by going through various steps of the generalization process targeting symbols. This study reflects Wittmann's intention in that well-understood mathematics and the context of the first type of empirical research as structure-genetic didactical analysis are considered in the design of the learning environment.

• The Journal of Sustainable Design and Educational Environment Research
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• v.20 no.2
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• pp.1-10
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• 2021

The results of research and analysis are as follows: First, there were 108 types of change patterns in the number of elementary school students. Second, based on the similarity of 108 types of change patterns in the number of students, a type system diagram was presented. Third, in the case of a total of 18 types of change patterns in the number of students, the number of students decreased significantly due to the establishment of additional schools on top of the existing schools. The result of a a long-term survey and analysis on the trend of increase and decrease in the number of students across the country shows an urgent need todevelop policy tasks across the entire school accommodation plan, such as the establishment of differentiated schools suitable for regional characteristics, relocation, consolidation, reorganization of school districts, remodeling, and appropriatization projects.

• Journal of the Korean Geographical Society
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• v.30 no.4
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• pp.364-388
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• 1995

Even though rarely recognized as a separate approach, the institutional approach in geography is defined as an attempt to seek an explanation of the phenomena of geographical interest through focusing on the effects of institutional structure and actions. It can provide interdisciplinary links with other works and can offer complementary explanations for geographical interests. The concerns for institutions in geography can be found in early studies, the study of the state, the managerial approach, and the regulation approach. The Korean financial systems can provide good examples to apply institutional concepts into creating spatial outcomes, as it has been regarded as a useful tool to promote Korean economic development. Behind the current spatial pattern of financial systems, four different stages of institutional changes are identified in Korea. Each stage has different institutional features reflecting unique spatial implication.