• Journal of Educational Research in Mathematics
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• v.22 no.3
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• pp.331-352
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• 2012

The purpose of the study is to verify what cognitive variables have significant effect on proportional problem solving. For this aim, the study classified proportional problem into well-structured, moderately-structured, ill-structured problem by the level of structuredness, then classified the cognitive variables as well into factual algorithm knowledge, conceptual knowledge, knowledge of problem type, quantity change recognition and meta-cognition(meta-regulation and meta-knowledge). Then, it verified what cognitive variables have significant effects on 6th graders' proportional problem solving abilities through multiple regression analysis technique. As a result of the analysis, different cognitive variables effect on solving proportional problem classified by the level of structuredness. Through the results, the study suggest how to teach and assess proportional reasoning and problem solving in elementary mathematics class.

• Education of Primary School Mathematics
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• v.15 no.2
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• pp.59-75
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• 2012

This study aims to find whether the solutions for well-structured problems learned in school can be transferred to the moderately-structured problem and ill-structured problem. For these purpose, research questions were set up as follows: First, what are the patterns of changes in strategies used in solving the mathematics problems with different level of structuredness? Second, From the group using and not using proportion algorithm strategy in solving moderately-structured problem and ill-structured problem, what features were observed when they were solving that problems? Followings are the findings from this study. First, for the lower level of structuredness, the frequency of using multiplicative strategy was increased and frequency of proportion algorithm strategy use was decreased. Second, the students who used multiplicative strategies and proportion algorithm strategies to solve structured and ill-structured problems exhibited qualitative differences in the degree of understanding concept of ratio and proportion. This study has an important meaning in that it provided new direction for transfer and analogical problem solving study in mathematics education.

• Journal of the Korean School Mathematics Society
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• v.16 no.4
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• pp.719-743
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• 2013

Proportional reasoning is considered as a difficult concept to most elementary school students and might be connect to functional thinking, algebraic thinking, and mathematical thinking later. The purpose of this study is to analyze the sixth graders' development level of proportional reasoning so that children's problem solving processes on different proportional problem items were investigated in a way how the problem type of proportion and the degree of ill-structured affect to their levels. Results showed that the greater part of participants solved problems on the level of proportional reasoning and various development levels according to type of problem. In addition, they showed highly the level of transition and proportional reasoning on missing value problems rather than numerical comparison problems.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.10a
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• pp.76-95
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• 1993

본 연구에서는 비.반구조적 문제의 구조화 과정을 지원하는 지식기반(knowledge-based) 의사결정지원시스템을 설계. 개발하였다. 문제의 구조화란 당면한 문제에 대한 인식을 한 후, 문제의 핵심과 관련된 요인을 추출하여 그들간의 관계를 모델화하는 것으로서, 본 연구에서는 구조화기법으로 방향성 그래프구조인 영향도(Influence Diagram)를 채택하였다. 특히 본 연구에서 제시된 시스템은, 의사결정자가 지식베이스에 자신의 관심영역에 관한 지식을 저장하여 사용할 수 있도록, 영역독립적(domain-independent)인 쉘(shell)의 구조로 설계되었다. 개발된 프로토타입인 IDMS를 R&D 평가와 관련된 의사결정분야에 적용하여 그 구조화과정을 보임으로써 현실문제에의 적용가능성을 제시하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.78-80
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• 2000

XML로 기술된 전자 문서를 논리적 구조에 따라 분할하여 객체 지향 데이터베이스에 저장하기 위한 연구가 많이 이루어지고 있다. 그러나, 그러한 접근은 몇몇 기본적인 접근 연산에 대해 성능이 떨어진다. 이 경우, 비분할 저장 구조 모델을 이용하면 이러한 문제를 어느 정도 보완할 수 있다. 본 논문에서는 구조화된 XML 문서의 효율적인 관리를 위해 혼합 저장 구조 모델을 제안한다. XML 문서를 분할과 비분할 모델이 혼합된 형태의 물리적 저장 구조로 구조 정보를 표현하면서 투명성을 제공하기 위한 객체 지향 메타 스키마를 제안하고, 이 메타 스키마로부터 동적으로 생성된 응용 데이터베이스 스키마를 통해 구조화된 문서를 객체 지향 데이터베이스에서 관리하는 방법을 제안한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.11a
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• pp.207-210
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• 2008

(비)구조화된 격자 상에 정의된 벡터 데이터는 다양한 과학 및 공학 분야에서 매우 중요하게 다루어진다. 이러한 데이터는 데카르트 격자 상의 데이터에 비해 많은 처리시간을 필요로 하는데, 이러한 문제는 계층 트리를 이용해서 빠르게 처리하는 것이 가능하다. 본 논문에서는 구조화된 격자 데이터에 대해 계산 공간을 기반으로한 계층 트리를 생성하고 이 트리를 이용해서 빠르게 데이터 샘플링을 처리하고자 했다. 이러한 방법을 이용해서 스트림라인 생성 시간을 평균 1800배 빨라지게 하는 것이 가능했다.

• Journal of Oral Medicine and Pain
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• v.30 no.1
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• pp.35-44
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• 2005

Purpose: The aim of this preliminary study was to evaluate the effect of Problem-Based Learning (PBL) curriculum on development of comprehension of basic medical knowledge and quality of semi-structured problem solving including scientific reasoning skill. This scientific reasoning contained five components including: size of simple, design of research cause-effect, construction of risk factor, analysis statistic of data, interpretation of result. Materials and Methods: Seoul National University Dental students (100) participated in this experience during two weeks, 2004. Forty eight multiple-choice questions (MCQ) concerned "Infection Control and Prevention" were asked before and after two sections of Lecture-Based Learning (LBL) and PBL (pretest-posttest control group design). A semi-structured problem in epidemiological research was asked to these students after two sections (posttest-only control group design). Data (mean and SD) were analysed using the t Test for two independent samples (p<.05), comparing PBL versus LBL. Results: Our analyse of scores show no difference between LBL and PBL in the development of comprehension of "Infection Control and Prevention". The quality problem solving (epidemiological research) was significantly different between the two groups (p=.029); specially, two components' scores of reflection on scientific reasoning cause-effect (p=.000) and interpretation of result (p=.001) were significantly better for PBL than for LBL. Conclusion: Theses results indicate that comparing LBL and PBL, PBL curriculum have not been disadvantaged in comprehension of basic knowledge, and have contributed to develop the scientific reasoning in problem solving.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.30 no.4
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• pp.329-334
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• 2017

The structures, which are made up with the huge number of degrees-of-freedom and the assembly of substructures, have a great complexity. In order to increase the computational efficiency, the analysis models have to be simplified. Many substructuring techniques have been developed to simplify large-scale engineering problems. The techniques are very powerful for solving nonlinear problems which require many iterative calculations. In this paper, a modal derivatives-based model order reduction method, which is able to capture the stretching-bending coupling behavior in geometrically nonlinear systems, is adopted and investigated for its performance evaluation. The quadratic terms in nonlinear beam theory, such as Green-Lagrange strains, can be explained by the modal derivatives. They can be obtained by taking the modal directional derivatives of eigenmodes and form the second order terms of modal reduction basis. The method proposed is then applied to a co-rotational finite element formulation that is well-suited for geometrically nonlinear problems. Numerical results reveal that the end-shortening effect is very important, in which a conventional modal reduction method does not work unless the full model is used. It is demonstrated that the modal derivative approach yields the best compromised result and is very promising for substructuring large-scale geometrically nonlinear problems.

• Journal of Elementary Mathematics Education in Korea
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• v.22 no.3
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• pp.309-330
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• 2018

The purpose of this study is to identify possibility of a mathematical problem posing ability by presenting problem posing tasks with different degrees of structure according to the study of Stoyanova and Ellerton(1996). Also, the results of this study suggest the direction of gifted elementary mathematics education to increase mathematical creativity. The research results showed that mathematical problem posing ability is likely to be a factor in identification of gifted students, and suggested directions for problem posing activities in education for mathematically gifted by investigating the characteristics of original problems. Although there are many criteria that distinguish between gifted and ordinary students, it is most desirable to utilize the measurement of fluency through the well-structured problem posing tasks in terms of efficiency, which is consistent with the findings of Jo Seokhee et al. (2007). It is possible to obtain fairly good reliability and validity in the measurement of fluency. On the other hand, the fact that the problem with depth of solving steps of 3 or more is likely to be a unique problem suggests that students should be encouraged to create multi-steps problems when teaching creative problem posing activities for the gifted. This implies that using multi-steps problems is an alternative method to identify gifted elementary students.

• The Journal of Korean Association of Computer Education
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• v.6 no.1
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• pp.95-107
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• 2003

For effective web-based teaching and learning, it is necessary to estimate. whether activities for it have attained to the learning goal. In HTML and file based item pool systems, it is difficult to manage, to create questions into various forms, and to share with other systems. It is also not easy to provide suitable questions according to the level of learners. On the contrary, XML document can systematically create a structured information. Since XML represents a structure with meaningful information units, it can be effectively used to manage, search, and store documents. Therefore, we designed and implemented a web-based item pool system based on XML, which can support leveled assessment by analyzing the level of learners and providing appropriate questions according to it.