• Title/Summary/Keyword: problem solving approach

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Cryptanalysis of LILI-128 with Overdefined Systems of Equations (과포화(Overdefined) 연립방정식을 이용한 LILI-128 스트림 암호에 대한 분석)

  • 문덕재;홍석희;이상진;임종인;은희천
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.13 no.1
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    • pp.139-146
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    • 2003
  • In this paper we demonstrate a cryptanalysis of the stream cipher LILI-128. Our approach to analysis on LILI-128 is to solve an overdefined system of multivariate equations. The LILI-128 keystream generato r[8] is a LFSR-based synchronous stream cipher with 128 bit key. This cipher consists of two parts, “CLOCK CONTROL”, pan and “DATA GENERATION”, part. We focus on the “DATA GENERATION”part. This part uses the function fd. that satisfies the third order of correlation immunity, high nonlinearity and balancedness. But, this function does not have highly nonlinear order(i.e. high degree in its algebraic normal form). We use this property of the function fd. We reduced the problem of recovering the secret key of LILI-128 to the problem of solving a largely overdefined system of multivariate equations of degree K=6. In our best version of the XL-based cryptanalysis we have the parameter D=7. Our fastest cryptanalysis of LILI-128 requires 2110.7 CPU clocks. This complexity can be achieved using only 226.3 keystream bits.

Vibrational energy flow in steel box girders: Dominant modes and components, and effective vibration reduction measures

  • Derui Kong;Xun Zhang;Cong Li;Keer Cui
    • Steel and Composite Structures
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    • v.50 no.3
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    • pp.347-362
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    • 2024
  • Controlling vibrations and noise in steel box girders is important for reducing noise pollution and avoiding discomfort to residents of dwellings along bridges. The fundamental approach to solving this problem involves first identifying the main path of transmission of the vibration energy and then cutting it off by using targeted measures. However, this requires an investigation of the characteristics of flow of vibration energy in the steel box girder, whereas most studies in the area have focused on analyzing its single-point frequency response and overall vibrations. To solve this problem, this study examines the transmission of vibrations through the segments of a steel box girder when it is subjected to harmonic loads through structural intensity analysis based on standard finite element software and a post-processing code created by the authors. We identified several frequencies that dominated the vibrations of the steel box girder as well as the factors that influenced their emergence. We also assessed the contributions of a variety of vibrational waves to power flow, and the results showed that bending waves were dominant in the top plate and in-plane waves in the vertical plate of the girder. Finally, we analyzed the effects of commonly used stiffened structures and steel-concrete composite structures on the flow of vibration energy in the girder, and verified their positive impacts on energy regionalization. In addition to providing an efficient tool for the relevant analyses, the work here informs research on optimizing steel box girders to reduce vibrations and noise in them.

A study on the application of legal design methodology for commercialization of security tokens

  • Sangyub Han;Hokyoung Ryu
    • Journal of the Korea Society of Computer and Information
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    • v.29 no.7
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    • pp.117-128
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    • 2024
  • In this paper, we propose a process for deriving priority tasks using the legal design technique in a situation where there is high uncertainty in the market and legal system regarding the commercialization of security tokens based on blockchain and distributed ledger technology. To issue and distribute securities tokens, we conducted a legal design workshop with participants who applied for innovative financial services (financial regulatory sandbox). During the workshop, participants harmonized their interests and deliberated on readiness, considering both legal and technical factors. The aim was to ascertain the feasibility of identifying prioritized objectives for future endeavors. The legal design technique facilitates consensus-building among stakeholders in an uncertain environment by confirming and adjusting differing perspectives and disagreements based on mutual understanding. The key stages include the empathetic process called "Family Therapy," the "N whys" for problem definition, and the speculative scenario design for problem-solving. This approach distinguishes itself from user-centered design thinking. Given the diverse stakeholders involved, effective facilitation by the facilitator is crucial during the legal design workshop preparation and execution.

Ontology Matching Method for Solving Ontology Heterogeneity Issue (온톨로지 이질성 문제를 해결하기 위한 온톨로지 매칭 방법)

  • Hongzhou Duan;Yongju Lee
    • The Journal of the Korea institute of electronic communication sciences
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    • v.19 no.3
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    • pp.571-576
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    • 2024
  • Ontologies are created by domain experts, but the same content may be expressed differently by each expert due to different understandings of domain knowledge. Since the ontology standardization is still lacking, multiple ontologies can be exist within the same domain, resulting in a phenomenon called the ontology heterogeneity. Therefore, we propose a novel ontology matching method that combines SCBOW(: Siames Continuois Bag Of Words) and BERT(: Bidirectional Encoder Representations from Transformers) models to solve the ontology heterogeneity issue. Ontologies are expressed as a graph and the SimRank algorithm is used to solve the one-to-many problem that can occur in ontology matching problems. Experimental results showed that our approach improves performance by about 8% over traditional matching algorithm. Proposed method can enhance and refine the alignment technology used in ontology matching.

Development and Evaluation of an Educational Program for the Clothing life Domain in Home Economics through a Theme-Based Integrated Approach (주제 중심 통합적 접근에 의한 가정 교과 의생활 영역 교육 프로그램 개발과 평가 - "의복관리"와 "섬유(재료)" 주제를 중심으로 -)

  • Kim, Nam-Eun;Lee, Hye-Ja
    • Journal of Korean Home Economics Education Association
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    • v.22 no.3
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    • pp.163-188
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    • 2010
  • This study set out to develop and evaluate an educational program for the Clothing Life of Home Economics through the theme-based integrated approach develop integrated thinking abilities for solving everyday problems. For those purposes, it selected a couple of themes in the area of Clothing Life toward which the theme-based integrated approach could be develop and evaluate an educational program. The developed program was applied and assessed in total 28 hours of field lessons given to eighth graders attending B Middle School in Busan Metropolitan City. The analysis stage involved an exploration into programs related to an integrated approach to other subjects; the design stage identification of program types; and the development stage theme selection according to the selection criteria. The previous studies were analyzed along with the Technology and Home Economics textbooks to select a theme. two themes "Clothing Management" and "Fabrics(Materials)" were selected after discussing with the students on the Messenger and with a group of experts. Then content was organized and composed around the themes by discussing connections with other subjects. There were three evaluation; one by experts, another through preliminary lessons, and the other through field lessons. Following the research procedure, a theme-based integrated program was developed for the two selected themes. It contained total 49 and 32 learning materials for "Clothing Management" and "Fabrics(Materials)," respectively. Those learning materials were comprised of experiments and practices according to the nature of the themes. Each program consisted of the goals, learning content, content organization chart, learning activities, and evaluation; learning activities experiences, practice and experiment activities, self-directed activities and problem-solving processes; and evaluations self-evaluation, teacher evaluation, peer evaluation, portfolio, and experiment reports. The program was assessed three times. The first and second evaluation results found that the program was well compatible with the current needs, was properly organized to give lessons through integration with other subjects, and continuously maintained the students' interest. They, however, requested that there should be detailed explanations about each part of the program content. In the third evaluation done by the students during field lessons, 60% of them said that the program was fun and its content was easy to understand, that they realized a theme could be connected to several other subjects, and that the program could be applied to actual life. The educational program through the theme-based integrated approach is significant in that it is an educational program for the area of Clothing Life and tries an integrated approach. It helped the students not only gather knowledge in an integrated manner, but put it to practical uses to solve various problems they faced in actual life by creatively changing integrated knowledge. The study will be hopefully used by many teachers so that the students solve problems based on the ability of integrating various knowledges organically.

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A Study on Scientific Thinking of Korean High School Students-With Reference to Logical Thinking and Reasoning Power- (고교생의 과학적 사고력에 관한 연구-논리적 사고와 추리력을 중심으로-)

  • Hwang, Keung-Yeon;Park, In-Keun;Kim, Tai-Sung
    • Journal of The Korean Association For Science Education
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    • v.9 no.1
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    • pp.19-37
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    • 1989
  • The purpose of this study was to investigate the development of logical thinking and scientific reasoning pattern of Korean high school students. To carry out this study subjects were selected about 2,000 Junior high school students, and about 4,100 senior high school students throughout the nation. They were identified as concrete, transitional or formal operational stage with the use of TOLT(the Test of Logical Thinking) by Tobin and Capie(1980), and TOSR(the Test of Scientific Reasoning) by W.A Farmer(1986). This study turned out that more than 76% of Junior high school students were classified as the concrete operational stage and about 44% of senior high school students were classified as the formal operational stage, while about 26% of them were still in the concrete operational level. This study showed that the main factor of the intellectual development of students is learning by the gradual advancement of their grades and especially entrance into the senior high school rather than by the physical growth. This study also showed that there are the take-off stage of the development of logical thinking between fourteen and fifteen years of their ages. Less than 25% of junior high school students were in the formal operational stages which are capable of control of variables, probabilistic, correlation and combinational logic in problem-solving situation, while 33-54% of senior high school students were in the formal operational levels. 38% of junior high school students were in the formal operational stage which is capable of proportional logic, while about 55% of senior high school students were in the formal operational stage. Less than 20% of senior high school students were classified as group of highly capable of scientific reasoning, while more than 23% of them were classified as group of poor capability. It also turned out that there are differences or no differences between male and female students of each school in problem-solving situation regarding each logic approach. These differences were proved to be fluctuating depending on the situations and their grades. The other results of this study is similar to those of other researches such as Tomlinson-Keasey 1972, Coleman 1973, Lawson 1973, Lawson and Renner 1974, Neimark 1975, Han 1982, and Kim 1989.

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A Case Study about Influence of Primary Mathematic Concepts on the Composition of Mathematic Concepts in 3rd grade Prodigies of Elementary Schools - Focusing on Addition and Multiplication of Fractions - (수학의 1차적 개념이 초등학교 3학년 영재아의 수학적 개념구성과정에 미치는 영향에 대한 사례연구 - 분수의 덧셈과 곱셈을 중심으로 -)

  • Kim, Hwa Soo
    • Journal of Gifted/Talented Education
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    • v.24 no.1
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    • pp.17-43
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    • 2014
  • On the subjects of elementary 3rd grade three child prodigies who had learned the four fundamental arithmetic operations and primary concepts of fraction, this study conducted a qualitative case research to examine how they composed schema of addition and multiplication of fractions and transformed schema through recognition of precise concepts and linking of concepts with addition and multiplication of fractions as the contents. That is to say, this study investigates what schema and transformed schema child prodigies form through composition of primary mathematic concepts to succeed in relational understanding of addition and multiplication of fractions, how they use their own formed schema and transformed schema for themselves to approach solutions to problems with addition and multiplication of fractions, and how the subjects' concept formation and schema in their problem solving competence proceed to carry out transformations. As a result, we can tell that precise recognition of primary concepts, schema, and transformed schema work as crucial factors when addition of fractions is associated with multiplication of fractions, and then that the schema and transformed schema that result from the connection among primary mathematic concepts and the precise recognition of the primary concepts play more important roles than any other factors in creative problem solving with respect to addition and multiplication of fractions.

The Strategic Thinking of Mathematically Gifted Elementary Students in LOGO Project Learning (LOGO를 이용한 프로젝트 학습에서 나타난 초등 수학영재 학생들의 전략적 사고)

  • Lew, Hee-Chan;Jang, In-Ok
    • Journal of Educational Research in Mathematics
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    • v.20 no.4
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    • pp.459-476
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    • 2010
  • The purpose of this study is to suggest a new direction in using LOGO as a gifted education program and to seek an effective approach for LOGO teaching and learning, by analyzing the strategic thinking of mathematically gifted elementary students. This research is exploratory and inquisitive qualitative inquiry, involving observations and analyses of the LOGO Project learning process. Four elementary students were selected and over 12 periods utilizing LOGO programming, data were collected, including screen captures from real learning situations, audio recordings, observation data from lessons involving experiments, and interviews with students. The findings from this research are as follows: First, in LOGO Project Learning, the mathematically gifted elementary students were found to utilize such strategic ways of thinking as inferential thinking in use of prior knowledge and thinking procedures, generalization in use of variables, integrated thinking in use of the integration of various commands, critical thinking involving evaluation of prior commands for problem-solving, progressive thinking involving understanding, and applying the current situation with new viewpoints, and flexible thinking involving the devising of various problem solving skills. Second, the students' debugging in LOGO programming included comparing and constrasting grammatical information of commands, graphic and procedures according to programming types and students' abilities, analytical thinking by breaking down procedures, geometry-analysis reasoning involving analyzing diagrams with errors, visualizing diagrams drawn following procedures, and the empirical reasoning on the relationships between the whole and specifics. In conclusion, the LOGO Project Learning was found to be a program for gifted students set apart from other programs, and an effective way to promote gifted students' higher-level thinking abilities.

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A Study on the Promotion of Regional Innovation and Industrial-Academic Cooperation Using Living Labs (리빙랩을 활용한 지역혁신과 산학협력 촉진방안)

  • Kim, Young Mi
    • Journal of Digital Convergence
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    • v.18 no.4
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    • pp.121-127
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    • 2020
  • Innovation in local industries and the development of public services require, among other things, shared growth with the concept of regional co-prosperity. Regional co-prosperity is essentially aimed at bridging regional balance or regional gaps, which means a relationship that can achieve shared growth through complementary cooperation. In this study, cases using living labs were drawn based on the current status of industry-academic cooperation at the level of regional innovation and its policy implications were sought. Local governments are making various attempts to solve regional problems and enhance the linkage effect of securing mutual competitiveness through co-prosperity cooperation autonomously. In particular, an effective approach has been continued by activating the Living Lab Network, a problem-solving mechanism, focusing on pending regional issues. Above all, one of the strategies for regional development should be linked to the establishment of a cooperative system for win-win cooperation and policy means to support it. The activation of cooperative programs with local universities, companies and local governments and the case of problem-solving using living labs. Therefore, it suggested that active participation by various stakeholders and a cooperative governance model were needed to enable Living Lab.

A Case Study on the Influence of the Schema of Learners Who Have Learned the Primary Concepts of the Four Arithmetic Operations on the relational Understanding of Power and Mixed Calculations (사칙연산의 1차적 개념을 학습한 학습자의 Schema가 거듭제곱과 혼합계산의 관계적 이해에 미치는 영향에 대한 사례연구)

  • Kim, Hwa Soo
    • Education of Primary School Mathematics
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    • v.16 no.3
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    • pp.251-266
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    • 2013
  • With elementary school students who have learned the primary concepts of the four arithmetic operations as its subjects, this study has investigated in depth how schema and transformed schema are composed by recognition of the correct concepts and connection of concepts, that is to say, what schema learners form along with transformed schema with the primary concepts of the four arithmetic operations to understand the secondary concepts when power and mixed calculations are taken into contents. It has also investigated how the subjects use the schema they have formed for themselves and the transformed schema to approach problem solving, and how their composition of concepts and schema in problem solving ability achieve transformations. As a result, we can tell that the recognition of precise primary concepts and transformed schema work as important factors in the development from the primary to the secondary concepts. Here, we can also see learn that the formation of the schema created due to the connection among the primary concepts and the recognition of them and of the transformed schema play more important roles in the development toward the secondary concepts and the solution of arithmetic problems than any other factors.