• Journal of the Korean School Mathematics Society
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• v.11 no.4
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• pp.609-627
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• 2008

The purpose of this research was to investigate the relationship between the students' strategy types and the recognition for proportional situations. The students' strategy types which were based on the results of ratio and proportion tests were divided into an additive type, a multiplicative type, and a formal type. This research analyzed the students' activities of categorization when were given the proportional problems and nonproportional problems to the students. And it also explored how to develop students' recognizing for the discrimination between the proportional situations and nonproportional situations. The results was the following. First, the students didn't discriminate the proportional situations and the nonproportional situations in the initial state but they came to discriminate little by little. Secondly, the students didn't discriminate the direct proportions and the inverse proportions until the last stage. Third, the multiplicative type was outperformed more than the formal type in solving the ratio and proportion problems but the formal type was outperformed more than the multiplicative type in discriminating between proportional situations and nonproportional situations. These results are interpreted as showing that solving ratio and proportion tasks and recognizing proportional situations are different aspects of proportional reasoning and it is necessary to understand multiplicative strategy with formal strategy in recognizing proportional situations.

• Journal of KIISE:Software and Applications
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• v.27 no.2
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• pp.120-133
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• 2000

Major obstruction of using formal methods for hybrid real-time systems in industry is the difficulty that engineers have in understanding and applying the quantitative methods in an abstract requirements phase. While formal methods technology in safety-critical systems can help increase confidence of software, difficulty and complexity in using them can cause another hazard. In order to overcome this obstruction, we propose a framework for qualitative requirements engineering of the hybrid real-time systems. It consists of a qualitative method for requirements specification, called QFM (Qualitative Formal Method), and a safety analysis method for the requirements based on a causality information, called CRSA (Causal Requirements Safety Analysis). QFM emphasizes the idea of a causal and qualitative reasoning in formal methods to reduce the cognitive burden of designers when specifying and validating the software requirements of hybrid safety systems. CRSA can evaluate the logical contribution of the software elements to the physical hazard of systems by utilizing the causality information that is kept during specification by QFM. Using the Shutdown System 2 of Wolsong nuclear power plants as a realistic example, we demonstrate the effectiveness of our approach.

• Journal of Korean Elementary Science Education
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• v.34 no.4
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• pp.419-433
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• 2015

Analogical reasoning is a central component of human cognition and contributes to scientific discovery and to develop science education. In this study, we investigated the process features of lower elementary school students' analogical reasoning to explain mixture concept. The subjects are 24 lower elementary students. And the research design includes three phases instruction to investigate the features of students' self generated analogy. Phase 1 is the introduction of analogy in which student learn to use analogy. Phase 2 is a POE class about mixture conception. Piaget and Inhelder studied the conception of mixing among children in relation to cognitive development. In phase 2, we taught the student with Piaget and Inhelder's the experiment and observed the features of learning process about mixture conception. Phase 3 is students' generation of analogy (self generated analogy) for the experienced phenomena in phase 2. We analyzed the students' responses through the three phases in the view of Gentner's Structure Mapping Theory. The results showed that many lower elementary school students even before formal operation stage understood the mixture conception and made well their self generated analogy to explain the mixture conception in spite of the difficulty of making self generated analogy.

• Journal of The Korean Association For Science Education
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• v.17 no.1
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• pp.75-83
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• 1997

The purpose of this study was to determine the strategies that middle school students used in solving problems concerning density and solubility. These were compared in the aspects of problem contexts for 42 students of varying logical reasoning ability, spatial ability, and learning approach. A coding scheme used consists of five categories: reading & organization, production, errors, evaluation, and strategy. Students' protocols were analyzed after intercoder agreement had been established to be .95. The results were as follows: 1. Students had more difficulties in reading and organizing the problems in everyday contexts than in scientific contexts. Students at the concrete-operational stage and / or surface approach were more likely to have difficulties in reading and organizing the problems than those at the formal-operational stage and / or deep approach. 2. Students tended to split up the solubility problems into sub-problems and to solve the density problem in everyday contexts in random manner. These were significantly correlated with the test scores concerning logical reasoning ability, spatial ability, and learning approach at the .1 level of significance. 3. Major errors in solving the density problems were to disregard the given information or generated and to use inappropriate information. Many errors in solving the solubility problems were found to be executive errors. The strategy to use the information given appropriately was positively related to students' logical reasoning ability, spatial ability, and learning approach. 4. More evaluation strategies were found in everyday contexts. Their strategies to grasp the meaning of answers and to check the math were significantly related to students' logical reasoning ability. 5. Students used the random trial-and-error strategy more than the systematic strategy and the systematic trial-and-error strategy, especially in everyday contexts. The strategies used by the students were significantly related to students' logical reasoning ability, spatial ability, and learning approach.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.837-850
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• 2002

In an attempt to accelerate the development of formal reasoning ability of students, 'Thinking Science' activities developed by the Cognitive Acceleration through Science Education(CASE) project were implemented to 841 students in 7th grade aged 12+ in six middle schools over a period of two years. Homogeneity between the CASE group and control group was tested with SRT II, while the improvement of formal reasoning ability of the students was tested with SRT VII. The results were analyzed by treatment, gender, and cognitive levels of the students. Statistically significant gains were shown in the CASE group compared with those in the control group. Cognitive level of girls in the CASE group significantly increased as compared with the control group, while there was moderate effect in boys. These results implied that the thinking science activities were effective in cognitive acceleration of girls aged 12+. It was shown that much more CASE students in pre or concrete operational level shifted to formal operational level as compared with the control group while there were significant effects in all levels (ES=0.31${\sim}$1.10) without showing any tendency.

• Journal of Korean Elementary Science Education
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• v.22 no.1
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• pp.1-14
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• 2003

This study investigated the effects of the cognitive acceleration program devised for accelerating the development of formal reasoning ability of students. ‘Thinking Science’ activities developed by the Cognitive Acceleration through Science Education(CASE) project were implemented to 420 students in 5th grade aged 10+ in four elementary schools over a period of two yea. Homogeneity between the experimental group and control group was tested with SRT II, and the improvement of formal reasoning ability of the students was tested with SRT III. The results were analyzed by treatment, gender, and cognitive levels of the students. Statistically significant gains were shown in the CASE group compared with those in the control group. Cognitive level of girls in the CASE group increased as compared with the control group, while there was moderate effect in boys for the primary school. These results implied that the thinking science activities were effective in cognitive acceleration of girls aged 10+. It was shown that much more CASE students in concrete operational level shifted to formal operational level as compared with the control group while there were no significant effects in the other levels for primary school.

• Communications of Mathematical Education
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• v.23 no.1
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• pp.145-174
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• 2009

Based on the thinking that people can understand more clearly when the problem is related with their prior knowledge, the Purpose of this study was to analysis students' informal knowledge, which is constructed through their mathematical experience in the context of real-world situations. According to this purpose, the following research questions were. 1) What is the characteristics of students' informal knowledge about fraction before formal fraction instruction in school? 2) What is the difference of informal knowledge of fraction according to reasoning ability and grade. To investigate these questions, 18 children of first, second and third grade(6 children per each grade) in C elementary school were selected. Among the various concept of fraction, part-whole fraction, quotient fraction, ratio fraction and measure fraction were selected for the interview. I recorded the interview on digital camera, drew up a protocol about interview contents, and analyzed and discussed them after numbering and comment. The conclusions are as follows: First, students already constructed informal knowledge before they learned formal knowledge about fraction. Among students' informal knowledge they knew correct concepts based on formal knowledge, but they also have ideas that would lead to misconceptions. Second, the informal knowledge constructed by children were different according to grade. This is because the informal knowledge is influenced by various experience on learning and everyday life. And the students having higher reasoning ability represented higher levels of knowledge. Third, because children are using informal knowledge from everyday life to learn formal knowledge, we should use these informal knowledge to instruct more efficiently.

• Journal of The Korean Association For Science Education
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• v.24 no.5
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• pp.977-986
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• 2004

The purpose of this study was to investigate the general transfer effects of Thinking Science program on the problem solving with compensational reasoning of the elementary school students. For this study, 156 5th grade and 138 6th grade students were selected from four elementary schools. The students were tested with SRT(Science Reasoning Task) and compensational reasoning task. Statistically significant gains on the development of compensational reasoning were shown by the experimental group implemented with Thinking Science activities compared to the group implemented with compensation activity only. The achievement of the experimental group was higher than that of the compensation activity group in solving problem with compensational reasoning, specially for the boys and students in both the mature concrete and the concrete generalization stage. The results of this study implied that implementation of Thinking Science program related to several formal reasoning were effective for the development of reasoning ability as a general-transfer.

• The KIPS Transactions:PartB
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• v.15B no.1
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• pp.45-52
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• 2008

As the recent development of the IT services, there is a urgent need of effective diagnosis system to present appropriate solution for the complicated problems of breakdown control, a cause analysis of breakdown and others. So we propose an intelligent diagnosis system that integrates the case-based reasoning and the artificial neural network to improve the system performance and to achieve optimal diagnosis. The case-based reasoning is a reasoning method that resolves the problems presented in current time through the past cases (experience). And it enables to make efficient reasoning by means of less complicated knowledge acquisition process, especially in the domain where it is difficult to extract formal rules. However, reasoning by using the case-based reasoning alone in diagnosis problem domain causes a problem of suggesting multiple causes on a given symptom. Since the suggested multiple causes of given symptom has the same weight, the unnecessary causes are also examined as well. In order to resolve such problems, the back-propagation learning algorithm of the artificial neural network is used to train the pairs of the causes and associated symptoms and find out the cause with the highest weight for occurrence to make more clarified and reliable diagnosis.

• Journal of The Korean Association For Science Education
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• v.20 no.2
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• pp.297-306
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• 2000

The purpose of this study was to examine the relationship among an achievement, a meaningful learning orientation and a reasoning ability. 149 third grade middle school students were tested. The achievement test was designed to measure students' interrelated understanding of genetics. A modified LPQ(Learning Process Questionnaires) was used to measure students' meaningful learning orientation. Students' reasoning ability were identified by the short version GALT(Group Assessment of Logical Thinking). Correlations between different variables were examined. Regression analyses were conducted to examine the predictive influence of meaningful learning orientation and reasoning ability on the achievement of students. And ANCOVA was used to identify the interaction of these variables on students' achievement. Students did not understand well enough the concepts of genetics. Meaningful learning orientation indicated a significant gender difference. Girls tend to do more meaningful learning than boys(p<.05). Many students(48.76%) were at the transitional cognitive level. Results of correlations indicated that students' attainment of meaningful understanding was significantly and positively related with a meaningful learning orientation and a reasoning ability. But there was no significant correlation between students' meaningful learning orientation and reasoning ability. Regression analyses indicated that learning orientation and reasoning ability were able to predict the achievement of students. They predicted better on solving genetics problem than understanding genetics problem. Results of ANCOVA showed that the test scores of genetics were significantly different according to not only learning orientation levels but also cognitive levels. But, there was no interaction between learning orientation and cognitive levels. Within the transitional and formal cognitive level, the meaningful learners performed significantly better than the rote learners on the test of genetics.