• The Mathematical Education
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• v.53 no.4
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• pp.509-524
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• 2014

This study was to investigate the types of errors and the frequency of errors to understand students' solving process on the descriptive items with the students of an excellent high school which located in a non-leveling local school district of Gyunggi Province. All 11 items were developed in the equation of a circle and 120 students who attended this high school participated in solving them. The result showed a tendency as follows: Logically invalid inference(Type A, 38.83%) of errors, Omission error of the problem solving process(Type B, 25%), Technical error(Type C, 15.67%), Wrong conclusion(Type D, 11.94%), Use of wrong theorem(Type E, 5.97%), and Use of wrong picture(Type F, 2.61%). The logically invalid inference the students showed with a largest tendency was made because of the lack of reflection. This meant that this error could be corrected in a little treatment of carefulness.

• Journal of Elementary Mathematics Education in Korea
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• v.10 no.2
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• pp.195-219
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• 2006

This study was proposed to analyze mathematical communication activity and mathematical attitudes while students were solving project problem and to consider how the conclusions effects mathematics education. This study analyzed through qualitative research method. The questions for this study are following, First, how does the process of the mathematical communication activity proceed during solving project problem in a small group? Second, what reactions can be shown on mathematical attitudes during solving project problem in a small group? Four project problems sampled from pilot study in order to examine these questions were applied on two small groups consisting of four 5th grade students. It was recorded while each group was finding out the solution of the given problems. Afterward, consequences were analyzed according to each question after all contents were noted. Consequently, conclusions can be derived as follows. First, it was shown that each student used different elements of contents in mathematical communication activity. Second, during mathematical communication activity, most students preferred common languages to mathematical ones. Third, it was found that each student has their own mathematical attitude. Fourth, Students were more interested in the game project problem and the practical using project problem than others.

• Journal of Environmental Impact Assessment
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• v.15 no.6
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• pp.435-441
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• 2006

For the calibration of rainfall-runoff model, automatic calibration methods are used instead of manual calibration to obtain the reliable modeling results. When mathematical programming techniques such as linear programming and nonlinear programming are applied, there is a possibility to arrive at the local optimum. To solve this problem, genetic algorithm is introduced in this study. It is very simple and easy to understand but also applicable to any complicated mathematical problem, and it can find out the global optimum solution effectively. The objective of this study is to develope a parameter optimization program that integrate a genetic algorithm and a rainfall-runoff model. The program can calibrate the various parameters related to the runoff process automatically. As a rainfall-runoff model, SWMM is applied. The automatic calibration program developed in this study is applied to the Jangcheon watershed flowing into the Youngrang Lake that is in the eutrophic state. Runoff surveys were carried out for two storm events on the Jangcheon watershed. The peak flow and runoff volume estimated by the calibrated model with the survey data shows good agreement with the observed values.

• Clean Technology
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• v.20 no.4
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• pp.339-348
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• 2014

Life cycle assessment (LCA) has become an important tool used to enhance the environmental performance of process systems and products. LCA is an essential element in design for environment (DfE) because LCA can be utilized to evaluate and analyze environmental impacts incurred in the life cycle and supply chain. This review presents methodologies that can be used to integrate LCA into DfE activities and reduce environmental impacts from process systems and products; and introduces case studies for water supply systems and cellular phones. LCA is first used to quantify environmental impacts and identify the principal contributor to high impacts. In the next step, environmental impacts from principal contributors can be reduced by using mathematical optimization tools as an engineering and technological approach and by utilizing the cooperation of professionals from a diverse range of fields. Because the methodologies and case studies can be applied and extended to other fields, this review paper can contribute to helping prevent environmental pollution and enhance the sustainability of our society.

• Journal of Educational Research in Mathematics
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• v.25 no.2
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• pp.157-175
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• 2015

This study was conducted with the aim to develop and improve the assessment literacy of teachers which enables it to develop and utilize the assessment items using a wide range of contexts on the basis of an understanding of math contents and mathematical process specified in the math curriculum and to analyze the results in an effective way. To analyze the changes in the development and improvement of the assessment literacy of preservice math teachers, the author of this study, using PISA items and assessment framework, analyzed the changes through the 1st and 2nd development of assessment items. The results showed the assessment literacy of preservice math teachers and their ability have been improved, implying that there is the necessity to develop a wide range of programs to improve the assessment literacy of preservice math teachers and provide such programs on a regular basis, which will facilitate effective math teaching and learning.

• School Mathematics
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• v.10 no.3
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• pp.401-422
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• 2008

In the current school curriculum, an alternative assessment method which focuses more on the problem solving process rather than the final solution is being investigated. The goal is to evaluate students' understanding of the subject. A descriptive evaluation is being suggested as a way of examining the thought process of the students by a structured analysis of the problem solving process. But currently, there are not enough descriptive problems available for teachers to effectively carry out the alternative assessment method in the elementary school mathematics curriculum. In this research, we surveyed 197 elementary school teachers in Seoul to determine the status of descriptive evaluation in elementary school mathematics and to understand the teachers perception about the new assessment method. The goal of the survey was to find an effective implication of the new assessment method in elementary mathematics classes. The research showed that the elementary teachers use this assessment method about 4 to 7 times per month in their classes. They give descriptive problem test anytime they think it is appropriate during the Instruction of the topic. More than 90% of the teachers were using this assessment method to improve students' creativity and mathematical thinking. The teachers in the survey also commented that the teachers' administrative responsibility should be reduced and that the school environment in general should be improved for the new assessment method to be successful. Finally the study also showed that development of more descriptive problems in each grade level is needed to progress the new assessment method.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.789-806
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• 2010

As calls for more attention toward social minority group increases in our society recently, in the field of mathematics education more attention toward an issue about mathematics underachievers is being amplified. Thus, the present study is to examine the effects of teaching method considering students' cognitive characteristics on mathematical underachievers' problem solving and mathematical disposition. For this study, 10 fifth graders identified as mathematical underachievers based on the results of the national level diagnosis assessment and school based assessment were voluntarily selected from an elementary school in Seoul. The results of this study found out the fact that students participating in this program improved in terms of an ability both to solve problems in various ways and to explain an process of problem solving using spoken or written language and drawings. In addition, learning environment respecting students' own mathematical ideas seems to positively influence students' attitudes toward mathematics learning and mathematical dispositions. Furthermore, this study pointed out that mathematical underachievers tend to have difficulty in expressing their own mathematical thinking by reason of linguistic limitation. Finally, the findings of this study imply that for effective teaching of mathematics underachievers, these students' own informal experience and knowledge about mathematics as well as their characteristics regarding learning difficulties should be strongly considered.

• The Mathematical Education
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• v.47 no.1
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• pp.11-25
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• 2008

The characteristics of the pseudo-conceptual or the pseudo-analytical behaviors according to the achievement level(i.e. advanced group, proficient group, basic group, and below-basic group) in grade 9 are as follows. The pseudo-conceptual or pseudo-analytical behaviors to get credit from teachers become conspicuous in lower achievement level. The high achieving students showed more pseudo-conceptual or pseudo-analytical behaviors without undergoing the process of reflection or control. The proficient group was short of control in computation, and the advanced group didn't control well in representation. The proficient group tended to depend on a past successful algorithm and behave habitually. Therefore, it is needed to teach mathematics according to the characteristic of pseudo-conceptual or pseudo-analytic behaviors shown in each achievement level.

• The Mathematical Education
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• v.39 no.2
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• pp.81-99
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• 2000

The Purpose of this study is to develop and implement an alternative secondary mathematics curriculum to enhance creative problem-solving abilities. The curriculum consisting of three main elements-content knowledge, process knowledge and creative thinking sills-as developed. Lessons were taught by a problem-based-learning method in an experimental group. In order to examine the effect of the curriculum, performance assessment was developed and used for pre and post.. There were significant group differences in the creative problem-solving abilities, so we could examine the effect of developed program and confirm the group differences in the attitude for lessons. But there were no significant group differences in motive for learning, a study skill and the achievement test.

• Journal of Environmental Impact Assessment
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• v.8 no.2
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• pp.83-93
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• 1999

ASPEN PLUS, a steady-state simulator, was used in this study for predicting emissions of VOCs and tracing the fate of all compounds in biodegradation processes. Mathematical models for the processes such as volatilization, reaction and clarification were adopted from literatures. Unlike most previous simulations that various pollutants were considered as a single component, COD or BOD, four components of water, biomass, VOCs and COD were included in this simulation. Sensitivity analysis of several physical parameters on the performance of the WWTP was conducted. Model predictions of VOCs emissions agreed well with the plant data. The simulator could provide design conditions for a future WWTP as well as monitoring/control regimes to an existing WWTP.