• Journal of KIISE:Computer Systems and Theory
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• v.35 no.9_10
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• pp.476-484
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• 2008

Most string problems and their solutions are relevant to diverse applications such as pattern matching, data compression, recently bioinformatics, and so on. However, there have been few works on the relations between string problems and cryptographic problems. In this paper, we consider the following string reconstruction problems and show how these problems can be applied to cryptography. Given a string x of length n over a constant-sized alphabet ${\sum}$ and a set W of strings of lengths at most an integer $k({\leq}n)$, the first problem is to find the sequence of strings in W that reconstruct x by the minimum number of concatenations. We propose an O(kn+L)-time algorithm for this problem, where L is the sum of all lengths of strings in a given set, using suffix trees and a shortest path algorithm for directed acyclic graphs. The other is a dynamic version of the first problem and we propose an $O(k^3n+L)$-time algorithm. Finally, we show that exponentiation problems that arise in cryptography can be successfully reduced to these problems and propose a new solution for exponentiation.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.676-678
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• 2008

임상 의무기록에 나타나는 많은 두문자어들은 기계적인 처리과정에서 의무기록의 모호성을 크게 증가시키기 때문에, 정보추출이나 텍스트 마이닝을 하기 전에 전처리 과정으로 의무기록이 정규화 되어야 한다. 본 연구에서는 임상 의무기록 중 하나인 퇴원요약지에 사용된 약어와 두문자어들의 모호성을 제거하기 위한 정규화 시스템을 설계하고 구현했다. 정규화를 위해 문맥정보를 이용하여 의무기록의 종류와 기록내 위치정보를 파악하였고 이를 이용하여 약어와 두문자어의 의미를 학습하고 분류하였다. 본 연구에서 구현한 정규화 시스템은 실험에서 6가지 두문자어들이 가지는 16가지 의미들에 대해 94.7%의 정확률을 얻었다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2000.08a
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• pp.205-208
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• 2000

문자영상의 인식분야에서는 다양한 잡음으로 인해 손상된 영상을 개선하는 영상의 전처리 과정을 아주 중요시하고 있다. 본 논문에서는 영상의 객체 윤곽을 보호하면서 충격잡음에 효과적인 비선형 중간값(median) 필터를 먼저 적용하고, 영상객체에 대해 선택적으로 축소하고 확대하는 형태학(morphological) 필터를 직렬로 조합함으로서 선명한 문자 영상을 획득하였고, 좀 더 현실적인 문자를 인식하도록 Genesis 영상처리 보드와 이를 제어하는 MIL(Matrox Image Library) 패키지를 사용하여 실시간적으로 구현해 보았다.

• Journal of Educational Research in Mathematics
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• v.24 no.3
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• pp.359-374
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• 2014

Students' difficulties and errors in relation to mathematical proofs are worth while to say one of the dilemmas in mathematics education. The potential elements of their difficulty are scattered over the process of proving in geometry as well as algebra. This study aims to investigate whether middle school students understand the context of algebraic proof including literal expressions. We applied 24 third-grade middle school students a test item which shows a proof including a literal expression and missing the conclusion. Over the half of them responded wrong answers based on only the literal expression without considering its context. Three of them were interviewed individually to show their thinking. As a result, we could find some characteristics of their thinking including the perspective on proof as checking the validity of algebraic expression and the gap between proving and understanding of proof etc. From these, we also discussed about several didactical implications.

• The Journal of the Acoustical Society of Korea
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• v.38 no.5
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• pp.601-606
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• 2019

This paper is a study on speech recognition in the Korean using grapheme unit (Cho-sumg [onset], Jung-sung [nucleus], Jong-sung [coda]). Here we make ASR (Automatic speech recognition) system without G2P (Grapheme to Phoneme) process and show that Deep learning based ASR systems can learn Korean pronunciation rules without G2P process. The proposed model is shown to reduce the word error rate in the presence of sufficient training data.

• Cross-Cultural Studies
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• v.25
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• pp.529-548
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• 2011

Zu Wen-Zao(朱文藻), Li Tiao-Yuan(李調元), Hong Liang-Ji(洪亮吉), Peng Yuan-Rui(彭元瑞), Qian Dong-Huan(錢東垣), Sun Xing-Yan(孫星衍), Ruan Yuan(阮元), Chen Zhan(陳?), Wu Shi-Fen(嗚式芬), Feng Gui-Fen(馮桂芬), He Shao-Ji(何紹基), Fan Zu-Yin(潘祖蔭) made the contributions to the theoretical construction to the science of Chinese characters in their books "Shuwenxizhuankao(說文繫傳考異)", "Liushufenhao(六書分毫)", "Liushuzhuanzhulu(六書轉注錄)", "Xiqinggujian(西淸古鑒)", "Xiaoeryajiaozheng(小爾雅校證)", "Jiujingzhengsuzikao(九經正俗字考)", "Jiguzhaizhongdingyiqikuanshi(積古齋鐘鼎?器款識)", "Shuwenshengxi(說文聲繫)", "Shuwenjiuzizhengyi(說文解字正義)", "Jungulu(?古錄)", "Shuwenjiuzizhukaozheng (說文解字段注考正)", "Shuowenduanzhubozheng(說文段注駁正)", "Haidongjinshilu(海東金石錄)". They analyzed the rules behind character construction, and tried to find out the nature of Chinese characters, the relationship between Chinese characters, the evolutionary laws of Chinese characters, the characteristic of ancient Chinese characters etc.

• School Mathematics
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• v.10 no.2
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• pp.139-154
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• 2008

The primary purpose of this study was to investigate how sixth grade elementary school students react to the types of letters use, what levels of understanding letters students are in and what difficulties are in understanding letters, and to raise issues about instructional methods of algebra. A descriptive study through pencil-and- paper tests was conducted. The test instruments consisted of 18 questions with 6 types of letters use. According to the results of testing, students' types of letter use and the levels of understanding letters were classified. The conclusions from the results of this study were as follows: First, the higher the types of letters use, the more sixth grade elementary school students had low scores on the types. Therefore, teaching methodologies of letters and expressions in the classroom need to encourage for students to improve their ability of using and understanding letter. Second, approximately 40% of students were categorized in level 3. Accordingly it is necessary to have a program of teaching and learning to improve their understanding levels of letters. Third, approximately 15% of students were categorized in level 0. In order to develop understanding of letters, it is important that students use letter evaluated and letter used as an object. Fourth, students had the difficulties in understanding letters. It is informative for teachers to understand these students' difficulties and thinking processes. Finally, we must treat the different uses of letters and introduce them successively according to the student's understanding levels of letters.

• School Mathematics
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• v.12 no.4
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• pp.605-617
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• 2010

This study explores the characteristics and roles of non-textual elements in secondary mathematics textbooks in the United States and South Korea, using a conceptual framework that I have developed: variety, contextuality, and connectivity. Analyzing five U.S. standards-based textbooks and 13 Korean textbooks, this study shows that although non-textual elements in mathematics textbooks are free of literal language, they exhibit different emphases and reflect assumptions about what is important in learning mathematics and how it can be taught and learned in a particular societal context (Mishra, 1999; Zazkis & Gadowsky, 2001). While there are similar patterns in the use of different types of non-textual elements in textbooks from both countries, different opportunities are provided for students to learn mathematics between the two countries.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.2
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• pp.216-222
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• 2008

This paper proposed the multi characters detection algorithm using Color segmentation and the closing curve feature of LoG Operator in order to complement the demerit of the existing research which is weak in complexity of background, variety of light and disordered line and similarity of left and background color, etc. The proposed multi characters detection algorithm divided into three parts : The feature detection, characters format and characters detection Parts in order to be possible to apply to image of various feature. After preprocess that the new multi characters detection algorithm that proposed in this paper used wavelet, morphology, hough transform which is the synthesis logical model in order to raise detection rate by acquiring the non-perfection characters as well as the perfection characters with processing OR operation after processing each color area by AND operation sequentially. And the proposal algorithm is simulated with natural images which include natural character area regardless of size, resolution and slant and so on of image. And the proposal algorithm in this paper is confirmed to an excellent detection rate by compared with the conventional detection algorithm in same image.

• Archives of design research
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• v.15 no.3
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• pp.249-258
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• 2002

This study is about the effect on the user's cognitive stress by font size when they read on PDA(Personal Digital Assistant). The evaluation was done through both subjective evaluation and physiological one, which is brain wave test, while the research and analysis were focused on the relationship between the user's cognitive stress and font size. The two final results were found out as follows. 1) Font sizes, which were tested, were 8, 10, 12, 14, and 16 points. Among theses, font size 14 was the least stressful for the users, while the most stressful size was found out 8 points. 2) The cerebral cortex reaction according to the font size activated occipital lobe, parietal lobe of occipital visual area. Here we could come to a very Important conclusion that the smaller font size on mobile information appliances made users the more stressed.