• The Mathematical Education
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• v.57 no.2
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• pp.111-136
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• 2018

This study suggests a framework for analyzing items based on the characteristics, and shows the relationship among the characteristics, difficulty, percentage of correct answers, academic achievement and the actual mathematical problem solving competency. Three mathematics educators' classification of 30 items of Mathematics 'Ga' type, on 2017 College Scholastic Ability Test, and the responses given by 148 high school students on the survey examining mathematical problem solving competency were statistically analyzed. The results show that there are only few items satisfying the characteristics for mathematical problem solving competency, and students feel ill-defined and non-routine items difficult, but in actual percentage of correct answers, routineness alone has an effect. For the items satisfying the characteristics, low-achieving group has difficulty in understanding problem, and low and intermediate-achieving group have difficulty in mathematical modelling. The findings can suggest criteria for mathematics teachers to use when developing mathematics questions evaluating problem solving competency.

• Journal of The Korean Association For Science Education
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• v.24 no.4
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• pp.774-784
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• 2004

In the previous study, six factors which could disturb students' problem solving in an everyday context were identified and discussed. In this study, teaching materials to help students overcome those disturbing factors for successful problem solving in an everyday context were developed and applied to twenty-nine grade 10 students, and the effects of teaching materials were analyzed. According to the analysis of the correlation between the performance in everyday context problem solving and the benefit from the teaching materials, it was found that students who received the help from the teaching materials showed better performance with statistical significance. And students noted that teaching materials were helpful for them to solve the physics problems. Analyzing the overall performance of students in solving the everyday context problem, students in the experimental group showed better performance than the control group and this performance difference was larger among low-score students in school science testing. However, these differences were not statistically significant because the sample size was small. And, based on the analysis of interviews with students, it was also found that some students who showed low performance might not receive help from the teaching materials because the materials were too complex to be read easily, or because the basic concepts needed to solve the problem were not understood. Therefore, the results obtained from the interviews will be used to design more effective teaching for problem solving in an everyday context.

• East Asian mathematical journal
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• v.26 no.4
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• pp.553-579
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• 2010

Geometric education emphasize reasoning ability and spatial sense through development of logical thinking and intuitions in space. Researches about space understanding go along with investigations of space perception ability which is composed of space relationship, space visualization, space direction etc. Especially space visualization is one of the factors which try conclusion with geometric problem solving. But studies about space visualization are limited to middle school geometric education, studies in elementary level haven't been done until now. Namely, discussions about elementary students' space visualization process and ability in plane or space figures is deficient in relation to geometric problem solving. This paper examines these aspects, especially in relation to plane and space problem solving in elementary levels. Firstly we propose the analysis frame to investigate a visualization process for plane problem solving and a visualization ability for space problem solving. Nextly we select 13 elementary students, and observe closely how a visualization process is progress and how a visualization ability is played role in geometric problem solving. Together with these analyses, we propose concrete examples of visualization ability which make a road to geometric problem solving. Through these analysis, this paper aims at deriving various discussions about visualization in geometric problem solving of the elementary mathematics.

• Korean Journal of Child Studies
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• v.28 no.6
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• pp.169-182
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• 2007

Creative problem solving skills in mathematics were measured by fluency, flexibility, and originality; cognitive strategies were measured by rehearsal, elaboration, organization, planning, monitoring, and regulating. The Creative Problem Solving Test in Mathematics developed at the Korea Educational Development Institute(Kim et al., 1997) and the Motivated Strategies for Learning Questionnaire(Pintrich & DeGroot, 1990) were administered to 84 subjects in grade 5(45 girls, 39 boys). Data were analyzed by Pearson's correlation, multiple regression analysis, and canonical correlation analysis. Results indicated that positive regulating predicted total score and fluency, flexibility, and originality scores of creative problem solving skills. Elaboration, rehearsal, organization, regulating, monitoring, and planning positively contributed to the fluency and flexibility scores of creative problem solving skills.

• Transactions of the Korean Society of Mechanical Engineers
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• v.7 no.1
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• pp.52-63
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• 1983

The purpose of the study is to find development of contact area, contact pressure and friction forces occurring at joints or connection areas inbetween structural members or mechanical parts. The problem has a pair of difficulties intrinsically; a constraint of displacement due to contact, and presence of work term by nonconservative friction force in the variational principle of the problem. Because of these difficulties, the variational principle remains in the form of inequality. It is resolved by penalty method and perturbation method making the inequality to an equality which is proper for computational purposes. A contact problem without friction is solved to find contact area and contact pressure, which are to be used as data for the analysis of the friction problem using perturbed variational principle. For numerical experiments, a Hertz problem, a rigid punch problem, and the latter one with friction effects are solved using $Q_2$-finite elements.

• Journal of the Korean earth science society
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• v.25 no.8
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• pp.647-655
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• 2004

PISA (Program for International Student Assessment) 2003, the second cycle of PISA, collected data with respect to students' cross-disciplinary problem solving capabilities. Problem solving is defined as the ability to use cognitive processes to solve real cross-disciplinary problems. For the purpose of PISA 2003 assessment, three problem types were chosen: Decision Making, System Analysis and Design, and Trouble Shooting. For this paper a preliminary analysis on Korean students' responses to the PISA 2003 problem-solving items was conducted. The quantitative analysis mainly focused on the difficulties of the PISA 2003 items, while the quantitative analysis dealt with students' responses to open-ended items, which helped understand Korean students' cognitive style and reasoning processes. According to the item analysis result, Korean students had difficulty in representing their answers with pictures or graphs, and interpreting long and complex text. They also showed low achievement with relatively unfamiliar topics or tasks. The paper concluded with several suggestions on improve the quality of science education.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.702-707
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• 2007

A Color Discerning Device(CDD) is the equipment to use in a Rice Processing Complex(RPC). A CDD can sorting discolored grain according to light and shade. The existing a CDD's driving performance is not so good as overseas machine. Besides, transportation process causes a defect in the mechanism from impact or harmonic excitation or etc. This study is represented the problem of CDD through experiment and simulation on a CDD. To analysis the problem of driving condition, devide each part of CDD for performed modal analysis. The problem of driving of driving condition and transportation process solved by carry out modal analysis and static analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.11a
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• pp.365-370
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• 2003

The problem of brake judder is typically caused by quality defects in manufacturing. This quality problem, however, can't be controlled deterministically and requires analyses and designs considering uncertainties. This paper presents a method for dynamic analysis of a brake judder considering uncertainties. Firstly, quality defects, which come from the uncertainties, are determined by examination of symptoms of the brake judder quality problem. Effective quality defects are selected by investigation of process capability and comparison of sensitivity of each quality defects and noise levels of the effective quality defects are determined. Secondly, flexible multibody dynamic analysis and finite element analysis according to the proposed method are carried out. Finally, The analysis results are compared with the test results with noise levels of the effective quality defects.

• Journal of the Korean Geosynthetics Society
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• v.20 no.3
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• pp.11-20
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• 2021

In this paper, the approximately coupled method of finite element method and boundary element method to obtain efficient and accurate analysis results is proposed for a two-dimensional elasto-static problem with a geometrically abruptly changing part. As the finite element of a two-dimensional problem, three-node and four-node plane stress element is applied, and as the boundary element of a two-dimensional problem, three-node boundary element is applied. In the modeling stage, firstly, an entire analysis target object is modeled as finite elements, and then a geometrically abruptly changing part is modeled as boundary elements. The boundary element is defined using the nodes defined for modeling finite elements. In the analysis stage, finite element analysis is firstly performed on a entire analysis target object, and boundary element analysis is automatically performed afterwards. As for the boundary conditions at boundary element analysis, displacement conditions and stress conditions, which are the results of finite element analysis, are applied. As a numerical example, the analysis results for a two-dimensional elasto-static problem, a plate with a crack, are presented and investigated.

• Journal of Korean Elementary Science Education
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• v.30 no.2
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• pp.213-231
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• 2011

The purpose of this study was to investigate knowledge types which the elementary science gifted students would use when solving a science problem, and to examine characteristics and types that were shown in the science problem solving process. For this study, 39 fifth graders and 38 sixth graders from Institute of Education for the Gifted Science Class were sampled in one National University of Education. The results of this study were as follows. First, for science problem solving, the elementary science gifted students used procedural knowledge and declarative knowledge at the same time, and procedural knowledge was more frequently used than declarative knowledge. Second, as for the characteristics in the understanding step of solving science problems, students tend to exactly figure out questions' given conditions and what to seek. In planning and solving stage, most of them used 3~4 different problem solving methods and strategies for solving. In evaluating stage, they mostly re-examined problem solving process for once or twice. Also, they did not correct the answer and had high confidence in their answers. Third, good solvers had used more complete or partially applied procedural knowledge and proper declarative knowledge than poor solvers. In the problem solving process, good solvers had more accurate problem-understanding and successful problem solving strategies. From characteristics shown in the good solvers' problem solving process, it is confirmed that the education program for science gifted students needs both studying on process of acquiring declarative knowledge and studying procedural knowledge for interpreting new situation, solving problem and deducting. In addition, in problem-understanding stage, it is required to develop divided and gradual programs for interpreting and symbolizing the problem, and for increasing the understanding.