• Journal of Science Education
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• v.38 no.3
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• pp.703-717
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• 2014

In physics, metal simulation is an important mechanism to understand and create concepts. If students have difficulty in mental simulation, understanding the concept of physics also gets difficult. By providing guide for spatial manipulation to students, 3D simulation contents can help them understand the concept of physics. In this study, the 3D simulation contents developed to help understanding the concept of light going straight and shadow is applied to 20 college students. The results, Hake gain is 0.93, showing high level of understanding about the class. In addition, through mental simulation, students predict the phenomenon well about the new context. This is shown that students' understanding of concept through 3D simulation contents are carried out well.

• Honam Mathematical Journal
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• v.36 no.3
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• pp.555-568
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• 2014

On the basis of the theory of a falling shadow and fuzzy sets, the notion of a falling fuzzy BCI-commutative ideal of a BCI-algebra is introduced. Relations between falling fuzzy BCI-commutative ideals and falling fuzzy ideals are given. Relations between fuzzy BCI-commutative ideals and falling fuzzy BCI-commutative ideals are provided. Characterizations of a falling fuzzy BCI-commutative ideal are established, and conditions for a falling fuzzy (closed) ideal to be a falling fuzzy BCI-commutative ideal are considered.

• Journal of the Optical Society of Korea
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• v.14 no.4
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• pp.368-375
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• 2010

Unlike document images, license plate images are mostly captured under uneven lighting conditions. In particular, a shadowed region has sharp intensity variation and sometimes that region has very high intensity by reflected light. This paper presents a new technique for thresholding license plate images. This approach consists of three parts. In the first part, it performs a rough thresholding and classifies the type of license plate to adjust some parameters optimally. Next, it identifies a shadow type and binarizes license plate images by adjusting the window size and location according to the shadow type. And finally, post-processing based on the cluster analysis is performed. Experimental results show that the proposed method outperformed five well-known methods.

• Journal of Korean Elementary Science Education
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• v.39 no.1
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• pp.26-39
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• 2020

Visual Representation Competence Taxonomy (VRC-T) was developed in previous study(Yoon, 2018) to provide a framework conducive to assess visual representation competence and to devise appropriate educational activities for it. This study is an extension of the previous study. It aimed to explore the usefulness of VRC-T and revise it by analyzing the patterns of visual representation use in science lessons. The researcher collected lesson plans on shadow principle from 11 pre-service and 13 in-service elementary teachers and conducted individual interviews regarding what visual representations they considered and how they tried to use them in science lessons. VRC-T was used as an analytical framework to examine the types and cognitive processes of visual representations. As a result, new categories were added and the revised VRC-T was completed (VRC-TR). It was also found that both pre- and in-service teachers mainly focused on 'interpreting' the 'descriptive representation' while designing their lesson plans. Additionally, in-service teachers showed more limited use of visual representations compared to pre-service teachers. In-service teachers largely relied on the national science textbooks, while pre-service teachers reflected their own learning experiences in their teacher-training program. These results showed that teachers' use of visual representations heavily relied on their prior learning and teaching experiences. The VRC-TR presented in this study and examples of class activities in each category can be helpful for teachers and researchers who want to use visual representations more effectively.

• Korean System Dynamics Review
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• v.12 no.4
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• pp.5-34
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• 2011

The purpose of this paper is to evaluate the policies for reducing private tutoring expenditure in Roh Mu Hyun and Lee Myeong Bak Government using Causal Loop analysis based on the Systems Thinking perspective. The results are as follows. First, high educational achievers receive more private tutoring than lowers and children who have rich parents have better chance to take private tutoring than the others. It reflects the social characteristics which emphasize the academic ability and educational background. Second, two governments implemented educational policies to control the private tutoring expenditure as balancing loops ; strengthening public education, providing after school programs and EBS KSAT teaching and improving the entrance exam of university. Third, they overlooked the unintended feedback loops coming from 1) incongruity between causes and countermeasures of shadow education 2) wrong perception of substitutional relationship between public education and shadow education 3) side effect of the policy increasing the weight of student record 4) problems of diversifying high schools 5) dilemma of easing the burden of testing through admission officer system. The conclusion is that policies of reducing the private education expenses have failed because two governments don't consider unintended Feedback Loops in the process of making education policies. So we have to make policies based on Systems Thinking and reducing private education expenses should not be the purpose of strengthening the public education.

• Journal of The Korean Association For Science Education
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• v.39 no.2
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• pp.295-305
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• 2019

In previous study, visual representation competence taxonomy (VRC-T), which is composed of two dimensions, was developed for the purpose of promoting effective visual representation use and research in science education. In this study, elementary school students' visual representation competence for shadow phenomenon was investigated using VRC-T. In terms of visual representation competence, 'interpretation' was the highest score, followed by 'construction' and 'integration'. It also showed that students' visual representation competence was not high even after learning shadow-related units in the regular curriculum. On the other hand, text-based scientific knowledge was not correlated with all categories of visual representation competence. This indicates that there is a need to emphasize visual representation more in science class. Finally, hierarchical relationship among cognitive processes of VRC-T was explored according to ordering theory. If the tolerance level is somewhat loosened, a linear hierarchical relationship was found between the six cognitive processes. This suggests that VRC-T is an analytical framework that can be useful when designing assessment tools, tasks, and science class activities to enhance visual representation competence.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.529-530
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• 2016

When the mountain accident occurred, the accident victims should inform anyone of information of the location and accident situation rapidly. But if you are in the radio shadow area where you cannot use GPS, 3G/4G, and wireless communication, you can't inform someone your accidents. In this paper, we suggest the emergency rescue request notification service in situation that victims can't report their accidents. This service is to send request message for rescue in radio shadow area, in mountain accident, by BLE(Bluetooth Low Energy).

• Honam Mathematical Journal
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• v.34 no.1
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• pp.125-133
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• 2012

Relations among falling fuzzy ideals, falling fuzzy implicative ideals, falling fuzzy positive implicative ideals and falling fuzzy commutative ideals are considered. Characterizations of falling fuzzy positive implicative ideals and other related ideals are discussed.

• Journal of The Korean Association For Science Education
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• v.30 no.7
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• pp.901-907
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• 2010

The purpose of this study is to analyze methods for measuring the size of the Earth, put forth in 6 different Korean 8th grade science textbooks. The research questions are as follows: 1) Do they adequately map out the experiments for measuring the size of the earth by using the concept of the sun's altitude? 2) Do they reduce the size of the sun like as the Earth is similarly downsized to the globe? 3) Do they suggest the precise experimental conditions for selecting two equal longitudinal spots for measuring the size of the earth? 4) Do they design adequate experiments for exact measurement? 5) Do they offer a proportional expression for seeking the size of globe which is easily understood by students? 6) Do they develop experiments to measure actual size of the earth? Four graduate students and one researcher took part in this study. All conditions were unanimously agreed upon by the participants. The results are as follows. First, one publishing company must include the concept of the sun's altitude to accurately measure the size of the Earth. However, some textbooks fail to mention this. As such, the concept of the sun's altitude must be introduced to accurately measure the size of the Earth. Second, a reduced size globe is used as the actual earth so; the sun should be factored in with a reduced light value. Third, you have to lay a stress on two points at the same longitude. In other words, a shadow located at the same longitude from two randomly selected points. Most textbooks mention two points at the same longitude but two of them design the experiment with a shadow at the same longitude. Fourth, we need a method to precisely measure the angle between a stick and its shadow. The angle between the stick and the tip of its shadow is the sun's altitude difference. Fifth, we need to present more specific proportional expressions for calculating the size of the globe. Only 3 out of the 6 texts employed a proportional expression. Sixth, we need to calculate the size of the earth by accurately presenting the scale of the globe to attain the goal of the experiment. Two of the texts analyzed, designed the experiment for the purpose of calculating the size of the globe. Three of the texts designed their experiments to calculate the radius of globe which is not even relevant to the purpose of experiment.

• Journal of the Korean Society of Earth Science Education
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• v.13 no.3
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• pp.270-283
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• 2020

The purpose of the study is to investigate the perception of elementary pre-service teachers about convergence program after conducting 'Making shadow book using my creative story' activity. The program consists elementary pre-service teachers to creat their own stories and using them to make a "shadow book." The program was conducted on 52 elementary pre-service teachers for eight weeks. After the end of the program, they were examined for their perception of the convergence program with the Likert scale questions and essay questions. The analysis results of the Likert scale questions showed that they scored very high on the objectives, contents and methods of the program, and the satisfaction, necessity and willingness to re-participate were also high. In addition, the analysis results based on keywords of essay questions about how the program operates, and its advantages and improvements made it possible to categorize them into instructional content, convergence education, teaching competency, thinking ability, psychology, and emotional experience. Through this study, we could see that by experiencing the convergence program ran by cooperative professors of different majors, elementary pre-service teachers naturally recognized the meaning, importance and necessity of convergence education, understood the contents of related subjects easily, and improved teaching competency. But, they also mentioned various improvements due to the situation of non-face-to-face classes.