• Journal of information and communication convergence engineering
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• 제8권5호
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• pp.602-607
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• 2010

Recently, one has realized that the threedimensional positioning technique used in GPS can be effectively applied to the modern two-dimensional positioning. Such a technique might has applied to the twodimensional positioning in fields of the mobile communication, eLORAN and the GPS jamming/ electronic warfare system. In the paper, we have studied on algorithms for two-dimensional positioning based on GPS Pseudorange Technique. The main works and results are summarized below. First, the linearized state equation was mathematically derived based on GPS pseudorange technique. Second, the geometry model with respect to triangles formed using unit-vectors were proposed for investigation of land-based radio positioning. Finally, the corresponding mathematical formulations for DOP values and covariance matrix were designed for two-dimensional positioning.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제15권1호
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• pp.15-30
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• 2011

We study to design educational Logo-based microworld environment equipped with 3D construction capability, 3D manipulation, and web-based communication. Extending the turtle metaphor of 2D Logo, we design simple and intuitive symbolic representation system that can create several turtle objects and operations. We also present various mathematization activities applying the turtle objects and suggest the way to make good use of them in mathematics education. In our microworld environment, the symbolic representations constructing the turtle objects can be used for web-based collaborative learning, communication, and assessments.

• 한국수학교육학회지시리즈D:수학교육연구
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• 제16권4호
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• pp.265-276
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• 2012

These days, with the emphasis on statistical literacy, the importance of communication is the focus of attention. Communication about statistics is important since it is a way of describing the understanding of concepts and the interpretation of data. However, students usually have trouble with expressing what they understand, especially through writing. In this paper, we examined preservice teachers' difficulties when they wrote about statistical concepts. By comparing preservice teachers' written responses and interview transcripts of the variance concept task, we could find the missing information in their written language compared to their verbal language. From the results, we found that preservice teachers had difficulty in connecting terms contextually and conceptually, presenting various factors of the concepts that they considered, and presenting the problem solving strategies that they used.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권11호
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• pp.5592-5609
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• 2017

JPEG steganography detection is an active research topic in the field of information hiding due to the wide use of JPEG image in social network, image-sharing websites, and Internet communication, etc. In this paper, a new steganalysis method for content-adaptive JPEG steganography is proposed by integrating the evolutionary feature selection and classifier ensemble selection. First, the whole framework of the proposed steganalysis method is presented and then the characteristic of the proposed method is analyzed. Second, the feature selection method based on genetic algorithm is given and the implement process is described in detail. Third, the method of classifier ensemble selection is proposed based on Pareto evolutionary optimization. The experimental results indicate the proposed steganalysis method can achieve a competitive detection performance by compared with the state-of-the-art steganalysis methods when used for the detection of the latest content-adaptive JPEG steganography algorithms.

• 한국수학교육학회지시리즈A:수학교육
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• 제43권1호
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• pp.51-74
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• 2004

During cooperative learning in small group, we investigate what characteristics children in elementary school show at several fields of mathematics and through communicating activity etc., what influence the cooperative learning does on children's attitude, thinking, problem solving, recognition. To know them, we observe the process of children's communication and evaluate children's attitude, thinking, problem solving, recognition with checklist at each lesson. Through this research, we conclude that the figure part is the most effective when we teach with cooperative learning type, and the cooperative learning evoke the vivid communication, and make progress in affirmative attitude, thinking etc. Also, in this thesis we suggest the points which teacher should consider when he/she use cooperative learning in small-group.

• 한국정보통신학회논문지
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• 제5권2호
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• pp.365-370
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• 2001

선형 TPMACA로부터 유도되는 여원 CA중 여원벡터가 0이 아닌 attractor인 경우의 여원 CA의 행동들을 분석하고, 선형 TPMACA의 0-트리의 한 개의 기본 경로를 이용하여 여원 CA의 상태전이그래프를 구성하는 알고리즘을 제안한다.

• 한국전자통신학회논문지
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• 제9권11호
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• pp.1297-1304
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• 2014

사람의 감정 중의 하나인 사랑은 사회학과 심리학에서 주된 관심사로 연구되어 왔다. 본 논문에서는 로미오와 줄리엣의 사랑 방정식[ ]에서 이들의 거동을 시계열과 위상 공간으로 나타내고, 이들 사이에 외부적인 자극인 3자가 개입했을 때의 관계를 시계열과 위상 공간으로 나타내어 이들 사이의 거동 관계를 분석한다.

• International Journal of Internet, Broadcasting and Communication
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• 제11권2호
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• pp.11-18
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• 2019

One of the key objectives of control systems is to maintain a system in a specific stable state. To achieve this goal, a variety of control techniques can be used and it is often uses a feedback control method. As known this kind of control methods requires mathematical model of the system. This article presents seesaw unstable system with two propellers which are controlled without use of a mathematical model instead. The goal was to control it using training data. For system control we use a logistic regression technique which is one of machine learning method. We tested our controller on the real model created in our laboratory and the experimental results show that instability of the seesaw system can be fixed at a given angle using the decision boundary estimated from the classification method. The results show that this control method for structural equilibrium can be used with relatively more accuracy of the decision boundary.

• International Journal of Internet, Broadcasting and Communication
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• 제13권2호
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• pp.120-126
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• 2021

The importance of mathematics is emerging to create new values and secure competitiveness in an intelligent information society based on the Fourth Industrial Revolution. This study was conducted with the aim of improving the academic performance and increasing interest of electronics majors in mathematics subjects. In order to develop learners' mathematical capabilities in major fields that utilize mathematics that electronics majors do not prefer, we have proposed a new teaching method to promote employment in mathematics-based electronics fields. In addition, to enhance learners' self-directed learning, we developed teaching methods for efficient mathematics subjects with programming languages as tools in electronics engineering and applied them to real-world teaching sites to effectively cultivate academic performance improvement of majors. Finally, we conducted a survey and statistically analyze the effectiveness of the developed teaching methods to present effective operational measures for mathematics education, an essential tool in intelligent information technology.

• 한국정보통신학회논문지
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• 제23권7호
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• pp.837-844
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• 2019

최근, 비디오 스트리밍에 대한 수요가 급증함에 따라서 무선 자원의 효율성을 높일 수 있는 스트리밍 기법에 대한 관심이 높아지고 있다. 본 논문에서는 무선 네트워크에서 수신단 캐싱 기능을 활용하여 비디오 스트리밍의 전송 효율을 획기적으로 개선할 수 있는 적응형 비디오 스트리밍 기법을 제안한다. 두 클라이언트가 동시에 동일한 비디오를 요청하는 경우에만 브로드캐스팅 기법으로 비디오 데이터를 전송할 수 있는 기존 방식과 달리, 제안 방식은 두 클라이언트들이 서로 다른 비디오를 요청하는 경우에도 각 클라이언트의 캐싱 정보가 특정 조건을 만족하면 브로드캐스트 기법으로 비디오를 전송할 수 있다. 본 논문에서는, 수학적 분석을 통하여 제안 방식의 평균 전송 시간을 분석하고 그 근사치를 제시한다. 또한, 다양한 시뮬레이션을 통하여 수학적 분석의 정확성을 검증한다. 수학적 분석과 시뮬레이션 결과에 따르면, 제안 방식은 기존 방식 대비 평균 전송 시간을 획기적으로 감소시킬 수 있다.