• Journal of Korean Elementary Science Education
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• v.33 no.4
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• pp.607-619
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• 2014

The purpose of this study is to investigate the degree of concept understanding on the stratum for elementary school students. For this objective, questions on the stratum concept were developed, and concept survey was conducted for random sampling of $5^{th}$ and $6^{th}$ grade 536 students. As a result, students chosen correct answers of the average 57.4% for 16 questions. Below the average rate of correct answers in each domain were 1 question in the definition of the stratum, 3 questions in formation of the stratum, and 4 questions in features of the stratum. Especially, the percentage of correct answers were appeared in lowly that the difference between the visible side and non visible side on the stratum, the definition and formation process of a fault and the main cause of the stratum's exposure. Also, between the residence, grade, and gender of students, there were significant differences in 2 questions, 7 questions, and 1 questions, respectively. Therefore, many elementary school students do not have high understanding about the stratum concept. Through the results of this study, it can be contributed to find an efficient ways as a basic data for modify misconceptions of the stratum to the scientific concept.

• Journal of The Korean Association For Science Education
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• v.15 no.3
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• pp.275-283
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• 1995

The purpose of this study was to suggest that the history of science be introduced to students in the secondary school to help understand the developmental process of the scientific concepts, especially the concept 'heat'. Reviewing the national and international researches related to students' concept 'heat' revealed that many students tend to grasp the wrong concept of heat based on the caloric theory. Studies on definitions and explanations of the concept 'heat' and related concepts in secondary school science textbooks indicated that the way 'heat' was described could not help students to correct their misconceptions. In conclusion we need to include the historical and developmental process of scientific concepts such as heat in textbooks.

• Journal of Elementary Mathematics Education in Korea
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• v.14 no.3
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• pp.885-905
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• 2010

This study questions that mathematical evaluations strive to memorize fragmentary knowledge and have an objective test. To solve these problems on mathematical education We did descriptive test. Through the descriptive test, students think and express their ideas freely using mathematical terms. We want to know if that procedure is correct or not, and, if they understand what was being presented. We studied this because We want to analyze where and what kinds of faults they committed, and be able to correct an error so as to establish a correct mathematical concept. The result from this study can be summarized as the following; First, the mistakes students make when solving the descriptive tests can be divided into six things: error of question understanding, error of concept principle, error of data using, error of solving procedure, error of recording procedure, and solving procedure omissions. Second, students had difficulty with the part of the descriptive test that used logical thinking defined by mathematical terms. Third, errors pattern varied as did students' ability level. For high level students, there were a lot of cases of the solving procedure being correct, but simple calculations were not correct. There were also some mistakes due to some students' lack of concept understanding. For middle level students, they couldn't understand questions well, and they analyzed questions arbitrarily. They also have a tendency to solve questions using a wrong strategy with data that only they can understand. Low level students generally had difficulty understanding questions. Even when they understood questions, they couldn't derive the answers because they have a shortage of related knowledge as well as low enthusiasm on the subject.

• Journal of Korean Elementary Science Education
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• v.24 no.1
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• pp.43-50
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• 2005

This study examined the effects of the result of ascertaining predictions on cognitive conflict and conceptual change when students teamed the concept of weightlessness. Participants were 200 pre-service elementary teachers. They answered the pretest composed of two items. Through the demonstration on either of two items of the pretest, they identified whether their predictions were correct or not. In addition, students' cognitive conflicts were measured. After brief instructional treatment, the posttest was conducted. The results of this study are as follows: The more students who identified their own predictions on the experiment were incorrect there were, the more effective it was on cognitive conflict and conceptual change. And cognitive conflicts and conceptual changes of students who identified that their predictions were incorrect were generated meaningfully more than those of students who identified that their predictions were correct. From these results, it is concluded that students who identified that their predictions were correct experience cognitive conflicts, but their cognitive conflicts and conceptual changes were smaller than those of students who identified that their predictions were incorrect.

• Journal of Information Processing Systems
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• v.10 no.4
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• pp.602-617
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• 2014

The performance of a cognitive radio network (CRN) solely depends on how precisely the secondary users can sense the presence or absence of primary users. The incorporation of a spatial false alarm makes deriving the probability of a correct decision a cumbersome task. Previous literature performed this task for the case of a received signal under a Normal probability density function case. In this paper we enhance the previous work, including the impact of carrier frequency, the gain of antennas on both sides, and antenna heights so as to observe the robustness against noise and interference and to make the correct decision of detection. Three small scale fading channels: Rayleigh, Normal, and Weibull were considered to get the real scenario of a CRN in an urban area. The incorporation of a maximal-ratio combining and selection combing with a variation of the number of received antennas have also been studied in order to achieve the correct decision of spectral sensing, so as to serve the cognitive users. Finally, we applied the above concept to a traffic model of the CRN, which we based on a two-dimensional state transition chain.

• Hwankyungkyoyuk
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• v.19 no.2 s.30
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• pp.122-132
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• 2006

This research compared the mechanism of the greenhouse effect in the atmosphere with retaining warmth in the actual greenhouse, analyzed the styles of explaining the greenhouse effect in current textbooks, and investigated teachers' and students' degrees of understanding the effect. The mechanisms of the actual greenhouse and the greenhouse effect are not the same. Nevertheless, in all the current textbooks, the radiation phenomenon by the atmosphere is described as the 'greenhouse effect'. Using the words of the 'greenhouse effect' to refer to the effect of air being kept warm by the heat absorbing gases, causes confusion of concepts. To make learners understand the greenhouse effect exactly, concrete principles such as radiating electromagnetic phenomenon should be explained. However, teachers and current textbooks explained the radiating electromagnetic phenomenon as actual greenhouse. Therefore, it is difficult for learners to understand the greenhouse effect, scientifically. Because of this, learners maybe confused about greenhouse effect concepts.

• Journal of Korean Elementary Science Education
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• v.23 no.3
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• pp.208-218
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• 2004

Many elementary school students have misconception related to dissolution and solution. Moreover, they usually fail to apply the results of the experiments in their science classes to their everyday life, and also have low science achievement. Therefore, they are not interested in science, and sometimes some of them are even afraid of it. The purposes of this study is to investigate the effects of concept mapping activity on science achievement and attitude. In addition, this study also aims at presenting the teaching and learning method of utilizing concept maps in order to have the students form correct concepts. The subjects were classified into two groups one group is composed of thirty-seven students (experimental group) who were participated in concept mapping activity, and the other is composed of thirty-eight students (comparison group) who were participated in the traditional teaching method. The major findings of this study are as follows: First, the concept mapping activity has a positive effect on improving students＇ science achievement. Second, the classes using concept maps have a good influence on forming students＇ science attitude. Third, the concept mapping activity is more effective in improving science achievement of mid and low level students. In conclusion, the loaming by concept mapping activity positively influence students＇ science achievement and attitude. Particularly for the students in mid and high levels, the effect is more remarkable.

• Journal of The Korean Association For Science Education
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• v.16 no.4
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• pp.340-350
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• 1996

Knowledge is composed through the interaction between the concept structure already held by students and their experience, and learning can be said to be the active process of solving the cognitive conflict caused by this interaction. Therefore, this study consists in showing the effective learning method and finding out the elements which the teacher has to own, through examining several forms of pre-conception or mis-conception of the inertia, the force-equilibrium, the action and reaction, the heat, and the electric current, and then finding out their solution and studying student's change in science concepts. For this study, the types of concept on the five above-mentioned materials which students have were examined through the concept-classifying question paper, and the classes to which the class mode for the change of concepts applied, were practised in each different classroom by each different instructor - a professor, a scientist, a teacher, and two students, respectively. And the effect of the teaching strategy based on these classes, and each different instructor' influence on the change of concept in students. were examined. The result of my study is as follows; 1. Students have various types of pre-conception which are different from science concept, and these types of pre-conception tend to last even after learning in class. 2. The thoughts on the correct science concept of the high school third-grade students who learned the physics in the traditional teaching method, and the second grade students who don't learn the physics yet, were nearly equal those of the second grade students by receiving the physics class through the cognitive conflict course were greatly changed especially that students showed the distinct change on mechanics and electric current. 3. Students didn't show the remarkable change of the science concept on the five materials in the four kinds of experimental classes by each different instructor but in the part of mechanics, there was the distinct change between the class by professor and those by the students. This was due to the difference of the authority and the attitude of the concept demonstrator. 1) The authority, the kind attitude, and the responsibility of the expert played an important role in the correct concept-formation of mechanics part - especially in the case of the mis-conception caused by the intuitive belief. 2) In the class by instructor with the democratic teaching method, the change of concept took place more easily, because in his class students could discuss the subject freely, so that they might experience the thought course to give them the confidence on the science concept.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.1
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• pp.64-79
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• 2017

This study was to evaluate the suitability of scientific questions as qualification examination for high school graduation by content validity and item response with three examinees and two preliminary examinees. As a result, scientific questions were concentrated on two units of six units of total, and application appeared to be lacking problem area by 8% compared to understanding and application. Examinees and preliminary examinees chose correct answers most by hap or guess, sometimes by experience or common sense, and the least by scientific concept. In addition, they could chose correct answers by hap or guess because there were words that implied the correct answer in questions and answers, or because they could compared and/or analyzed questions and answers. With these results, two proposals were suggested as follows; (1) scientific questions of qualification examination for high school graduation should measure basic scientific literacy. (2) specific criteria for science literacy in qualification examination for high school graduation should be set.

• Asia pacific journal of information systems
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• v.3 no.1
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• pp.155-189
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• 1993

Empirical studies have shown that the performance of decision tree induction usually improves when the trees are pruned. Whether these results hold in general and to what extent pruning improves the accuracy of a concept have not been investigated theoretically. This paper provides a theoretical study of pruning. We focus on a particular type of pruning and determine a bound on the error due to pruning. This is combined with PAC (Probably Approximately Correct) Learning theory to determine a sample size sufficient to guarantee a probabilistic bound on the concept error. We also discuss additional pruning rules and give an analysis for the pruning error.