• 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.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.796-799
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• 2006

This paper presents a new method for automatic detection of skew in a document image using mathematical morphology. To speed up processing, we use reduced image but it still requires long time to estimate the skew angle so the proposed method works with region of interest, not with whole image. Character strings are connected by using morphological closing operation and a component labeling is used to select region of interest. The method considers the lowermost pixels of characters in candidate regions in the binary image of original document image. Experimental results shows that the proposed method is extremely fast and robust as well as independent of script forms.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2201-2206
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• 2008

This paper presents a method of constructing the Linear Digital Switching Function(LDSF) 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(DCG) 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.

• East Asian mathematical journal
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• v.40 no.2
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• pp.209-229
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• 2024

In this study, we design a teaching unit that constructs Pascal graphs and extended Pascal triangles to explore number patterns inherent in them. This teaching unit is designed to consider the diachronic process of teaching-learning by combining Dörfler's theoretical generalization model with Wittmann's design science ideas, which are applied to the didactical practice of mathematization. In the teaching unit, considering the teaching-learning level of prospective teachers who studied discrete mathematics, we generalize the well-known Pascal triangle and its number patterns to extended Pascal triangles which have directed graphs(called Pascal graphs) as geometric models. In this process, the use of symbols and the introduction of variables are exhibited as important means of generalization. It provides practical experiences of mathematization to prospective teachers by going through various steps of the generalization process targeting symbols. This study reflects Wittmann's intention in that well-understood mathematics and the context of the first type of empirical research as structure-genetic didactical analysis are considered in the design of the learning environment.

• Communications of Mathematical Education
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• v.30 no.2
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• pp.199-223
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• 2016

The purpose of this study is to investigate how first and second graders in middle school take in integrated understanding about the concept of function. The data was collected through the questionnaire conducted by the first and second-year students at A, B middle school in Cheongju. The questionnaire consisted of 14 questions related to the extent of understanding a concept of function, the ability to express function and to translate function. The results are summarized as follows. First, the percentage of correct answer made a difference according to the types of representation. Questions leading students to translate a task into a table or an equation showed quite high correct response rates. However, questions asking students to translate a task into graphs showed high incorrect responses. Second, the result shows that students have the different viewpoints depending on their grades when they have to determine whether the suggested situation belongs to function. The first-year students tended to consider function as the concept of 'definition'. On the other hand, the second-year students emphasized 'equation' of function. Finally, only a few students can distinguish the various situations and representations into the definition of function. This result shows that students didn't get the integrated understanding of the concept of function.

• Education of Primary School Mathematics
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• v.21 no.1
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• pp.55-73
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• 2018

The purpose of this study is to investigate the effects of cognitive activity on cognitive activities that students imagine and cope with continuously changing quantitative changes in functional tasks represented by linguistic expressions, table of value, and geometric patterns, We identified covariational reasoning levels and investigated the characteristics of students' reasoning process according to the levels of covariational reasoning in the elementary quantitative problem situations. Participants were seven 4th grade elementary students using the questionnaires. The selected students were given study materials. We observed the students' activity sheets and conducted in-depth interviews. As a result of the study, the students' covariational reasoning level for two quantities that are continuously covaried was found to be five, and different reasoning process was shown in quantitative problem situations according to students' covariational reasoning levels. In particular, students with low covariational level had difficulty in grasping the two variables and solved the problem mainly by using the table of value, while the students with the level of chunky and smooth continuous covariation were different from those who considered the flow of time variables. Based on the results of the study, we suggested that various problems related with continuous covariation should be provided and the meanings of the tasks should be analyzed by the teachers.

• The Journal of Korean Academy of Sensory Integration
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• v.6 no.1
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• pp.1-12
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• 2008

Objective : The purpose of this study is to provide reference to functional level of sensory integration of in the low-grads school age, based on the Clinical Observation of Motor and Postural Skills (COMPS) and to examine correlation between the function of sensory integration and academic achievement. Method : Two schools ("J" and "S") have been selected indiscriminately among 56 elementary schools located in Gimhae-si, GyeongNam and then one class from each school was voluntarily chosen among all second-grade classes of the schools. The total number of students in those two classes was 69 (34 boys and 35 girls). Subjects had no developmental problem and no history of referral regarding neurological conditions. Three skilled researchers administrated the COMPS together, and each researcher executed two sub-items of the COMPS. As result of the academic achievement, score data of midterm- and final-exam in the spring semester were collected. The scores of 'Korean language' and 'Math', common examination subjects in both schools, were utilized for data analysis in this study. Results : Statically, there was no significant correlation between the COMPS Weighted Scores and any academic achievements. In a dispersion graphic analysis, however, the total achievement showed significant negative-correlation with the area of 'Rapid Forearm Rotation' and significant positive-correlation with the area of 'Supine Flexion'. In terms of the Math achievement, there are significant negative-correlation with rapid forearm rotation and asymmetrical tonic neck reflex, and significant positive-correlation with the area of 'Supine Flexion'. Students with higher score of the Korean language showed a tendency to get higher Weighted Score and Minus Adjustment Score, and those with lower score of the Math showed a tendency to get higher COMPS scores in all area except the area of 'Supine Flexion'. There was a statically significant difference in the COMPS scores depend on the age among general characteristics. As student older, all COMPS scores, except those in the area of 'Slow Motion' and 'Supine Flexion, were higher. Conclusions : There is somehow reliable correlation between sensory integration function and academic achievement although no statistical significance found in this study. The information from this study may contribute to initiate developing a normative-reference to screen earlier and more alertly sensory integration dysfunctions for school-age children. Further study is recommended trying to find out more reliable matter regarding low grade- schooler's academic achievement.