• Journal of the Korean Electrochemical Society
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• v.23 no.4
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• pp.81-89
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• 2020

To understand the performance of the electrochemical device, the analysis of the mechanism of ionic conduction is important. However, due to the ionic interaction in the electrolyte and the complexity of the electrolyte structure, a clear analysis method of the ion conduction mechanism has not been proposed. Instead, a variety of mathematical models have been devised to explain the mechanism of ion conduction, and this review introduces the Arrhenius and Vogel-Tammann-Fulcher (VTF) model. In general, the above two mathematical models are used to describe the temperature dependence of the transport properties of electrolytes such as ionic conductivity, diffusion coefficient, and viscosity, and a suitable model can be determined through the linearity of the graph consisting of the logarithm of the moving property and the reciprocal of the temperature. Currently, many electrolyte studies are evaluating the suitability of the above two models for electrolytes by varying the composition and temperature range, and the ion conduction mechanism analysis and activation energy calculation are in progress. However, since there are no models that can accurately describe the transport properties of electrolytes, new models and improvement of existing models are needed.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.7
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• pp.9-16
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• 2008

For the efficient routing on a Sensor Network, one may consider a deployment problem to interconnect the sensor nodes optimally. There is an analogous theoretic problem: the Steiner Tree problem of finding the tree that interconnects given points on a plane optimally. One may use the approximation algorithm for the problem to find out the deployment that interconnects the sensor nodes almost optimally. However, the Steiner Tree problem is to interconnect mathematical set of points on a Euclidean plane, and so involves particular cases that do not occur on Sensor Networks. Thus the approach of using the algorithm does not make a proper way of analysis. Differently from the randomly given locations of mathematical points on a Euclidean plane, the locations of sensors on Sensor Networks are assumed to be physically dispersed over some moderate distance with each other. By designing an approximation algorithm for the Sensor Networks in terms of that physical property, one may produce the execution time and the approximation ratio to the optimality that are appropriate for the problem of interconnecting Sensor Networks.

• Journal of the Korean School Mathematics Society
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• v.25 no.3
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• pp.225-241
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• 2022

The purpose of this study is to analyze and present what aspects of the concept of function prospective mathematics secondary teachers emphasize when designing a class that introduces the concept of function using curriculum and textbooks. For this purpose, virtual instruction and reflections on virtual instruction were analyzed. The results are as follows. The prospective mathematics secondary teachers consider and introduce the concepts of function as correspondences and processes. Their conception of function was consistently observed during virtual instruction and reflections on virtual instruction. The prospective mathematics secondary teachers' conception of function was closely related to the form of expressing functions. These results provi e implications for prospective mathematics secondary teachers' education for introducing the concept of function based on the dependent relation between variables presented in the 2015 revision of the national mathematics curriculum.

• Journal of the Korea Society of Computer and Information
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• v.29 no.5
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• pp.203-211
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• 2024

Utilizing programming languages for data visualization can enhance the efficiency and effectiveness in handling data volume, processing time, and flexibility. However, practice is required to become proficient in programming. Therefore public data-based the problem bank was developed to practice data visualization in a programming automatic assessment system. Public data were collected based on topics suggested in the curriculum and were preprocessed to make it suitable for users to visualize. The problem bank was associated with the mathematics curriculum to learn various data visualization methods. The developed problems were reviewed to expert and pilot testing, which validated the level of the questions and the potential of integrating data visualization in math education. However, feedback indicated a lack of student interest in the topics, leading us to develop additional questions using student-center data. The developed problem bank is expected to be used when students who have learned Python in primary school information gifted or middle school or higher learn data visualization.

• School Mathematics
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• v.13 no.1
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• pp.155-173
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• 2011

Problem representation is a key aspect in solving word problems. The purpose of this study was to investigate the effects of instructional program based on visual schema representing five types of word problems(Marshall, 1995). Two second grade classes of an elementary school located in Seoul were participated in this study. In experimental class, an instructional program including schema tools were suggested and administered and the other comparison group did have regular classes using diagrams and tables. Pre and post test including 15 word problems each were utilized to test students' problem solving ability. In addition, test scores on students' language ability were used to control the effects of word comprehension level on problem solving. The result revealed that experimental group showed higher problem representation and solving scores after controling the effects of pre-test. In addition, there was significant positive correlation between the ability to apply exact problem schema and problem solving results. The correlation was .58. This study showed even in the early developmental stage young students can get benefits from having instructions of word problem schema.

• Journal of the Korean Society of Earth Science Education
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• v.10 no.1
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• pp.50-61
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• 2017

The purpose of this study is to analysis eye tracking for high school students' learning styles in the process of solving in the behavioral domains of the College Scholastic Ability Test on Earth Science I. The subjects of this study were 50 students from two classes out of 4 classes in E high school in Chungcheong province. Among them, we conducted experiments by randomly sampling 2 students of each type of learning based on the criteria that they had not encountered the problem of Earth Science I from the past two years. The findings indicate that the item correctness rate of divergers, assimilators, convergers, and accommodators were higher in the knowledge domain, application domain, knowledge-understanding domain, and understanding domain. This confirms that there is a difference among the four learning styles in the level of achievement according to the behavioral areas of the assessment questions. The latter finding was that the high eye-share of AOI 2 appeared higher than AOI 1, 3, 4 in the course of solving the problems. This is because the four types of learners pay more careful attention to the AOI 2 area, which is the cue-or-information area of problem solving, that is, the Table, Figure, and Graph area. Therefore, in order to secure the fairness and objectivity of the selection, it is necessary that an equal number of questions of each behavioral domain be selected on the Earth Science I Test of the College Scholastic Ability Test in general. Besides, it seems to be necessary that the knowledge, understanding, application, and the behavior area of the inquiry be highly correlated with the AOI 2 area in development of test questions.

• Magazine of the Korea Concrete Institute
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• v.3 no.1
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• pp.71-78
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• 1991

Moleclar size distribution of three AC-20 asphalt cements were observed using high pressure - gel permeation chromatograph (HP-GPC). Bituminous concrete specimens were made using the asphalt cements and one aggre¬gate in laboratory to measure mechanical properties, tensile strength CIS) and resilient modulusCM,J. in dry and wet conditons. Results of mechanical property tests and profile of molecular size distribution of asphalt cements were analyzed to evaluate the relatonship of mechanical property with chromatogram. Regression analy¬sis showed a strong correlation between a mechanical property and sliced percent areas of chromatogram. Mathematical prediction models were developed based on the regression analysis. It was shown that characteris¬tics of asphalt cement chromatogram could be successfully used for estimation of selected mechanical property of asphalt concrete .

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.95-98
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• 2016

민주주의의 꽃, 제 20 대 국회의원 선거가 막을 내렸다. 지난 선거에서는 방송사뿐만 아니라 정당들도 엄청난 비용 지출과 노력이 소요되었다. 한 예로, 지난 4. 13 총선거 (제 20 대 국회의원)에서 방송 3 사 출구조사 비용으로 약 66 억원 이상이 지출됐다. 그리고 정당에서는 여론조사 비용으로 약 70 억원 이상을 지출했다. 이러한 큰 비용 지출과, 담당자들의 노력을 줄이기 위해 본 논문에서는 텍스트 마이닝과 감정분석을 적용한 후보 당선자 예측 어플리케이션을 제안한다. 첫째, 소셜 그래프 모델을 소개하여 지역 구조를 발견한다. 둘째, 텍스트 마이닝 기법을 이용하여, 후보자 관련 데이터를 가공한다. 셋째, 텍스트 감정 분석을 통해 후보자의 정보를 수치화 한다. 본 논문의 성능과 효율성을 평가하기 위해, 제 20 대 국회의원 선거에 사례연구를 진행하였다. 제안한 방법이 정확도와 수학적 통계 검증을 통해 가치 있는 효율성을 보였다. 선거방송을 위한 후보자 예측 도구의 도입으로 향후 선거(방송)에서의 큰 비용과 노력을 줄이는데 도움을 줄 것이라 기대한다.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.69-71
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• 2007

최근 들어 전력 계통은 점차 복잡해지고 계통의 규모 역시 빠른 속도로 성장하고 있다. 한국전력거래소는 전력계통의 안정적, 경제적 운영을 담당하고 있는 기관으로 '01년 현재의 에너지관리시스템(EMS)를 도입하여 실시간 전력계통에 대한 정확한 판단을 기반으로 전력계통의 안정성과 경제성 확보에 주력하고 있다. EMS의 대표적인 기능은 계통데이터의 수집(SCADA), 자동발전제어(AGC), 계통해석(NA) 등으로 대별되며, 이중 계통해석 기능은 프로그램 규모면에서 가장 큰 부분을 차지하고 있다. 계통해석 기능은 또다시 상태추정(SE), 상정사고분석(CA), 안전도해석(SENH), 고장해석(SCT) 등의 프로그램으로 구성되어 다양한 실시간 계통해석을 수행하게 된다. 전력계통 해석은 먼저 대상계통을 수학적 모델로 정식화하기 전에 계통망의 기하학적 구조를 기술하는 단계가 필요한데 이를 토폴로지 처리라고 하며, 보통 그래프이론인 노트(Node)와 마디(Branch)를 사용하여 전력계통망을 구성하는 요소들의 연결관계를 정의하게 된다. 본고는 이론적 수준을 넘어 EMS의 계통해석 기능에서 실계통을 해석하기 위해 쓰이고 있는 토폴로지 처리의 기본 알고리즘을 분석하여 국내 전력산업 기술 선진화에 기여하고자 한다.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.88-93
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• 2016

This paper presents a method of constructing the highly performance switching circuit(HPSC) over finite fields. The proposed method is as following. First of all, we extract the input/output relationship of linear characteristics for the given digital switching functions, Next, we convert the input/output relationship to Directed Cyclic Graph using basic gates adder and coefficient multiplier that are defined by mathematical properties in finite fields. Also, we propose the new factorization method for matrix characteristics equation that represent the relationship of the input/output characteristics. The proposed method have properties of generalization and regularity. Also, the proposed method is possible to any prime number multiplication expression.