• Journal of the Korea Institute of Information Security & Cryptology
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• v.19 no.5
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• pp.17-24
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• 2009

Zhang et al. proposed a improved fast correlation attack on stream ciphers at SAC'08[8]. This attack is based on the fast correlation attack proposed at Crypto'00 and combined with FWT(fast Walsh transform). Given various attack environments, they presented complexities and success probabilities of the proposed attack algorithm. However, we found that our simulation results of the proposed attack algorithm are different from them presented in [8]. In this paper, we correct results of the proposed attack algorithm by analyzing it theoretically. And we propose a threshold of valid bias.

• International Journal of Computer Science & Network Security
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• v.21 no.3
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• pp.206-211
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• 2021

Internet users are increasingly invited to express their opinions on various subjects in social networks, e-commerce sites, news sites, forums, etc. Much of this information, which describes feelings, becomes the subject of study in several areas of research such as: "Sensing opinions and analyzing feelings". It is the process of identifying the polarity of the feelings held in the opinions found in the interactions of Internet users on the web and classifying them as positive, negative, or neutral. In this article, we suggest the implementation of a sentiment analysis tool that has the role of detecting the polarity of opinions from people about COVID-19 extracted from social media (tweeter) in the Arabic language and to know the impact of the pre-processing phase on the opinions classification. The results show gaps in this area of research, first of all, the lack of resources when collecting data. Second, Arabic language is more complexes in pre-processing step, especially the dialects in the pre-treatment phase. But ultimately the results obtained are promising.

• Research in Mathematical Education
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• v.26 no.2
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• pp.45-61
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• 2023

Number talks as a brief instructional routine benefits students and teachers. In general, the routines consist of four steps- introducing, posing questions, collecting answers, sharing ideas. This paper focuses on the sharing ideas step in which multiple strategies are shared by students because teachers sometimes do not know what to do with these multiple ideas. One way is to support students to engage in comparison given that teachers are expected to support students to compare strategies in number talks. This paper explores whether and how 15 prospective teachers supported students in their practicum classroom to compare different strategies in their enacted number talk. In this paper, 15 videos of number talks enacted by the prospective teachers were collected. Analyzing the videos produced multiple episodes in relation to comparing strategies, including 1) where prospective teachers created pre-conditions for comparison, 2) where they invited students for comparison, 3) where they pressed students to compare, and 4) where they offered their own way to compare. There were two patterns that might limit the potential of having multiple strategies as conditions for comparison. Additionally, this paper found that even though the prospective teachers missed opportunities to support students to compare different strategies, there were two ways for teachers to support students to engage in comparison. These findings can be used for mathematics teacher educators to support prospective teachers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.1020-1041
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• 2024

With the development of covert communication technologies, the number of covert communication technologies using blockchain as a carrier is increasing. However, using the transaction amount of digital currency as a carrier for covert communication has problems such as low embedding rate, large consumption of transaction amount, and easy detection. In this paper, firstly, by experimentally analyzing the distribution of bitcoin transaction amounts, we determine the most suitable range of amounts for matrix decomposition. Secondly, we design a novel matrix decomposition method that can successfully decompose a large amount matrix into two small amount matrices and utilize the elements in the small amount matrices for covert communication. Finally, we analyze the feasibility of the novel matrix decomposition method in this scheme in detail from four aspects, and verify it by experimental comparison, which proves that our scheme not only improves the embedding rate and reduces the consumption of transaction amount, but also has a certain degree of resistance to detection.

• Journal of The Korean Association For Science Education
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• v.34 no.2
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• pp.63-78
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• 2014

Integrative STEM education is an engineering design-based learning approach that purposefully integrates the content and process of STEM disciplines and can extend its concept to integration with other school subjects. This study was part of fundamental research to develop an integrative STEM education program based on the science inquiry process. The specific objectives of this study were to review relevant literature related to STEM education, analyze the key elements and value of STEM education, develop an integrative STEM education model based on the science inquiry process, and suggest an exemplary program. This study conducted a systematic literature review to confirm key elements for integrative STEM education and finally constructed the integrative STEM education model through analyzing key inquiry processes extracted from prior studies. This model turned out to be valid because the average CVR value obtained from expert group was 0.78. The integrative STEM education model based on the science inquiry process consisted of two perspectives of the content and inquiry process. The content can contain science, technology, engineering, and liberal arts/artistic topics that students can learn in a real world context/problem. Also, the inquiry process is a problem-solving process that contains design and construction and is based on the science inquiry. It could integrate the technological/engineering problem solving process and/or mathematical problem solving process. Students can improve their interest in STEM subjects by analyzing real world problems, designing possible solutions, and implementing the best design as well as acquire knowledge, inquiry methods, and skills systematically. In addition, the developed programs could be utilized in schools to enhance students' understanding of STEM disciplines and interest in mathematics and science. The programs could be used as a basis for fostering convergence literacy and cultivating integrated and design-based problem-solving ability.

• Communications of Mathematical Education
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• v.27 no.1
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• pp.39-62
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• 2013

On the standards or elements of teaching evaluation, the Korea Institute of Curriculum and Evaluation(KICE) has carried out the following research such as : 1) development of the standards on teaching evaluation between 2004 and 2006, and 2) investigation on the elements of Teacher Knowledge. The purposes of development of evaluation standards for mathematics teaching through those studies were to improve not only mathematics teachers' professionalism but also their own teaching methods or strategies. In this study, the standards were revised and modified by analyzing the results of those studies focused on the knowledge of subject matter knowledge, knowledge of learners' understanding, teaching and learning methods and assessments, and teaching contexts. For this purpose, according to those evaluation domains of each teacher knowledge, elements on teaching evaluation focused on the teacher's knowledge were established using the instructional evaluation framework, which is developed in this study, including the four areas of knowledge obtaining, instructional planning, instructional implementation, and instructional reflection. In this study, 1st and 2nd pilot studies was accomplished for revising evaluation standards and as a result, the procedure for implementing mathematics teaching using evaluation standards was changed to evaluate teachers own teaching using the standards focused on instructional reflection and according to the degree of satisfaction on reflecting their own teaching, standards on knowledge obtaining, instructional planning, instructional implementation would be utilized. Teacher survey is accomplished two times, by the subject of seven teachers. According ot the result of the first teacher questionnaire which was consisted of the essay type of questions on the degree of understanding the content of standards, the evaluation standards were revised. According ot the result of the second teacher questionnaire which was consisted of the essay type of questions on the application of standards, the evaluation standards were revised finally and the way of how to use the standards efficiently was suggested.

• Journal of Educational Research in Mathematics
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• v.22 no.1
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• pp.1-22
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• 2012

The purpose of this study is to understand Korea students' characteristics as well as to give important information of improving our education using comparative analysis of framework, test booklets, test results between PISA 2009 and NAEA 2009. PISA 2009 was administered on May of 2009 and NAEA was administered on October of same year. The summary of the results of comparing two assessment is as follows First, cut score of NAEA Advance level is bigger than the cut score of level 5, which is considered as high achievement level. The cut score of Basic level of NAEA is also higher than the level 2 of PISA, which is considered as basic achievement level. This phenomenon can show that NAEA achievement level is set little bit higher than the achievement level of PISA in mathematics domain. Second, the percentage of female students on higher level was higher than that of male students. In suburban area, the percentage of high level was small and the percentage of low level was big. Third, students of Advanced level are distributed concentrating in PISA levels 4~6, Proficient achievement level concentrating in PISA levels 3~5, Basic achievement level concentrating in PISA levels 2~4, and below basic achievement levels concentrating in below level 1 and level 3 of PISA. Fourth, the correlation between NAEA 2009 and PISA 2009 achievement scores are significantly positive. However, the correlation of subscales were low. Fifth, analysis of non-equivalent group, 11 items located in 'change and relationship', 'uncertainty', 'connection cluster' domains found to be significantly different. The percent correct showed very big difference. The analysis results presents the implication of mathematics curriculum, teaching and learning methods as well as National Assessment of Educational Achievement.

• The Mathematical Education
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• v.63 no.2
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• pp.255-272
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• 2024

This study aims to design mathematics-integrated classes that cultivate artificial intelligence (AI) thinking and to analyze students' AI thinking within these classes. To do this, four classes were designed through the integration of the AI4K12 Initiative's AI Big Ideas with the 2015 revised elementary mathematics curriculum. Implementation of three classes took place with 5th and 6th grade elementary school students. Leveraging the computational thinking taxonomy and the AI thinking components, a comprehensive framework for analyzing of AI thinking was established. Using this framework, analysis of students' AI thinking during these classes was conducted based on classroom discourse and supplementary worksheets. The results of the analysis were peer-reviewed by two researchers. The research findings affirm the potential of mathematics-integrated classes in nurturing students' AI thinking and underscore the viability of AI education for elementary school students. The classes, based on AI Big Ideas, facilitated elementary students' understanding of AI concepts and principles, enhanced their grasp of mathematical content elements, and reinforced mathematical process aspects. Furthermore, through activities that maintain structural consistency with previous problem-solving methods while applying them to new problems, the potential for the transfer of AI thinking was evidenced.

• Journal of the Korean School Mathematics Society
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• v.15 no.3
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• pp.535-563
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• 2012

This study was conducted to confirm the necessity of analogical thinking and to empirically verify the effectiveness of analogical reasoning through the visual representation by analyzing the factors of problem solving depending on analogical conditions. Four conditions (a visual representation mapping condition, a conceptual mapping condition, a retrieval hint condition and no hint condition) were set up for the above purpose and 80 twelfth-grade students from C high-School in Cheong-Ju, Chung-Buk participated in the present study as subjects. They solved the same mathematical problem about sequence of complex numbers in their differed process requirements for analogical transfer. The problem solving rates for each condition were analyzed by Chi-square analysis using SPSS 12.0 program. The results of this study indicate that retrieval of base knowledge is restricted when participants do not use analogy intentionally in problem solving and the mapping of the base and target concepts through the visual representation would be closely related to successful analogical transfer. As the results of this study offer, analogical thinking is necessary while solving mathematical problems and it supports empirically the conclusion that recognition of the relational similarity between base and target concepts by the aid of visual representation is closely associated with successful problem solving.

• Journal of Elementary Mathematics Education in Korea
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• v.18 no.2
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• pp.211-236
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• 2014

The purpose of this study is to investigate teacher's knowledge of concept of equality and derive implications about proper teaching methods. To solve these study problems, three elementary school teachers are chosen for this study, and a pencil-and paper tests for comprehension of the equality concept targeting 72 students for elementary school that the teachers are in charge of the students was carried out. Also, The semi-structured interview(using a questionnaire) was conducted for analyzing of the teachers' knowledge of the equality concept. The findings are as follows. First, during the lesson, the teachers' reading of equal sign has a decisive effect on the students' the way of reading. Second, teachers tend to interpret the concept of equality as a systematic analysis rather than a relational analysis, and use a equal sign focusing on meaning of 'same result'. So, Students also can't interpret the concept of equality as a relational analysis. Third, under the influence of teacher's feedback or reaction, making the mistake of the using equal sign of students reoccurred continually. Fourth, teachers misjudged some of examples of the nonstandard context equation for teaching elementary school students. Furthermore, during the lesson, they usually used a limited equality context. So, students can't have a chance to learn equality in a plenty of context. Thus, the knowledge of teachers and their lesson has decisive influence on the comprehension of students about the equality concept. So, Teacher has to focus on the meaning of the equality as a relational analysis and teach them in a plenty of context. With this, lots of study and in-service training are needed to enhance knowledge of teachers. And more of lesson programs and materials have to provided on the instruction manual for teaching the meaning of the equality.