• School Mathematics
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• v.7 no.1
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• pp.55-75
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• 2005

Mathematical symbolizing is an important part of mathematics learning. But many students have difficulties m symbolizing mathematical ideas formally. If students had experiences inventing their own mathematical symbols and developing them to conventional ones natural way, i.e. learning mathematical symbols via expressive approaches, they could understand and use formal mathematical symbols meaningfully. These experiences are especially valuable for students who meet mathematical symbols for the first time. Hence, there are needs to investigate how early elementary school students can and should experience meaningful mathematical symbolizing. The purpose of this study was to analyze students' mathematical symbolizing processes and characteristics of theses. We carried out teaching experiments that promoted meaningful mathematical symbolizing among eight first graders. And then we analyzed students' symbolizing processes and characteristics of expressive approaches to mathematical symbols in early elementary students. As a result, we could places mathematical symbolizing processes developed in the teaching experiments under five categories. And we extracted and discussed several characteristics of early elementary students' meaningful mathematical symbolizing processes.

• Electrical & Electronic Materials
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• v.10 no.9
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• pp.916-921
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• 1997

In this study Characteristics of 3-D underwater object recognition independent of translation using the self-made ultrasonic sensor fabricated with porous piezoelectric resonator and presented. The sensor was satisfied with requirement of ultrasonic sensor. The recognition rates for the training data and the testing data are 97.45 and 91.25[%] respectively using the self-made ultrasonic sensor and SCL(Simple Competitive Learning) neural network. According to the experimental results It is believed that the self-made ultrasonic sensor can be applied as sensor of SONAR system.

• Journal of The Korean Association For Science Education
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• v.22 no.4
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• pp.820-836
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• 2002

Constructivism has had a great influence on science education over the last two decades. The purpose of this article is twofold: First, to describe the characteristics of constructivism and, second, to suggest an ideal forms of science education in Korea as implied in constructivism. A review of the literatures in the first area shows that constructivism is philosophical/psychological view which believe in the social nature of the construction of scientific knowledge and its learning. And the analyses of a few schools of constructivism suggest decision-making as a goal of science education, learning as the active construction of meaning through interaction between learner and learning environments, and discussion and cooperation as appropriate teaching strategies. At the same time, the results necessitate teaching ethical aspects of science in the secondary schools, and also imply that performance assessment must be emphasized in evaluation of science education.

• Korean Journal of Remote Sensing
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• v.39 no.5_3
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• pp.891-907
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• 2023

Compact Advanced Satellite 500-4 (CAS500-4) is scheduled to be launched to collect high spatial resolution data focusing on vegetation applications. To achieve this goal, accurate surface reflectance retrieval through atmospheric correction is crucial. Therefore, a machine learning-based atmospheric correction algorithm was developed to simulate atmospheric correction from a radiative transfer model using Sentinel-2 data that have similarspectral characteristics as CAS500-4. The algorithm was then evaluated mainly for forest areas. Utilizing the atmospheric correction parameters extracted from Sentinel-2 and GEOKOMPSAT-2A (GK-2A), the atmospheric correction algorithm was developed based on Random Forest and Light Gradient Boosting Machine (LGBM). Between the two machine learning techniques, LGBM performed better when considering both accuracy and efficiency. Except for one station, the results had a correlation coefficient of more than 0.91 and well-reflected temporal variations of the Normalized Difference Vegetation Index (i.e., vegetation phenology). GK-2A provides Aerosol Optical Depth (AOD) and water vapor, which are essential parameters for atmospheric correction, but additional processing should be required in the future to mitigate the problem caused by their many missing values. This study provided the basis for the atmospheric correction of CAS500-4 by developing a machine learning-based atmospheric correction simulation algorithm.

• The Journal of the Korea Contents Association
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• v.10 no.9
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• pp.487-495
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• 2010

Online content evaluation standards were suggested in order to improve quality of education for informatics gifted students in this paper. This evaluation standards were developed by thinking and learning style and characteristics of gifted students which were presented in preceding research. The evaluation standards were reviewed through reliability analysis as well as analysis of the characteristics of items and validity analysis by experts of informatics gifted student education sector. In the result of analysis, reliability of items has been very reliable. Level of difficulty and discrimination about the characteristics of items has also shown satisfactory value. Developed the evaluation standards has 5 evaluation categories such as "talent development", "Interaction", and others. It also has 11 evaluation factors and 40 evaluation items. The online content evaluation standards can be helpful and useful in order to develop qualitative online contents and select online contents for informatics gifted student.

• Journal of the Korea Society of Computer and Information
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• v.16 no.3
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• pp.175-187
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• 2011

Since insects play important roles in existence of plants and other animals in the natural environment, they are considered as necessary biological resources from the perspectives of those biodiversity conservation and national utilization strategy. For the conservation and utilization of insect species, an observational learning environment is needed for non-experts such as citizens and students to take interest in insects in the natural ecosystem. The insect identification is a main factor for the observational learning. A current time-consuming search method by insect classification is inefficient because it needs much time for the non-experts who lack insect knowledge to identify insect species. To solve this problem, we proposed an smart phone-based insect identification inference system that helps the non-experts identify insect species from observational characteristics in the natural environment. This system is based on the similarity between the observational information by an observer and the biological insect characteristics. For this system, we classified the observational characteristics of insects into 27 elements according to order, family, and species, and proposed similarity indexes to search similar insects. In addition, we developed an insect identification inference prototype system to show this study's viability and performed comparison experimentation between our system and a general insect classification search method. As the results, we showed that our system is more effective in identifying insect species and it can be more efficient in search time.

• Journal of Intelligence and Information Systems
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• v.26 no.3
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• pp.149-169
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• 2020

"The Urban Renewal New Deal project", one of the government's major national projects, is about developing underdeveloped areas by investing 50 trillion won in 100 locations on the first year and 500 over the next four years. This project is drawing keen attention from the media and local governments. However, the project model which fails to reflect the original characteristics of the area as it divides project area into five categories: "Our Neighborhood Restoration, Housing Maintenance Support Type, General Neighborhood Type, Central Urban Type, and Economic Base Type," According to keywords for successful urban regeneration in Korea, "resident participation," "regional specialization," "ministerial cooperation" and "public-private cooperation", when local governments propose urban regeneration projects to the government, they can see that it is most important to accurately understand the characteristics of the city and push ahead with the projects in a way that suits the characteristics of the city with the help of local residents and private companies. In addition, considering the gentrification problem, which is one of the side effects of urban regeneration projects, it is important to select and implement urban regeneration types suitable for the characteristics of the area. In order to supplement the limitations of the 'Urban Regeneration New Deal Project' methodology, this study aims to propose a system that recommends urban regeneration types suitable for urban regeneration sites by utilizing various machine learning algorithms, referring to the urban regeneration types of the '2025 Seoul Metropolitan Government Urban Regeneration Strategy Plan' promoted based on regional characteristics. There are four types of urban regeneration in Seoul: "Low-use Low-Level Development, Abandonment, Deteriorated Housing, and Specialization of Historical and Cultural Resources" (Shon and Park, 2017). In order to identify regional characteristics, approximately 100,000 text data were collected for 22 regions where the project was carried out for a total of four types of urban regeneration. Using the collected data, we drew key keywords for each region according to the type of urban regeneration and conducted topic modeling to explore whether there were differences between types. As a result, it was confirmed that a number of topics related to real estate and economy appeared in old residential areas, and in the case of declining and underdeveloped areas, topics reflecting the characteristics of areas where industrial activities were active in the past appeared. In the case of the historical and cultural resource area, since it is an area that contains traces of the past, many keywords related to the government appeared. Therefore, it was possible to confirm political topics and cultural topics resulting from various events. Finally, in the case of low-use and under-developed areas, many topics on real estate and accessibility are emerging, so accessibility is good. It mainly had the characteristics of a region where development is planned or is likely to be developed. Furthermore, a model was implemented that proposes urban regeneration types tailored to regional characteristics for regions other than Seoul. Machine learning technology was used to implement the model, and training data and test data were randomly extracted at an 8:2 ratio and used. In order to compare the performance between various models, the input variables are set in two ways: Count Vector and TF-IDF Vector, and as Classifier, there are 5 types of SVM (Support Vector Machine), Decision Tree, Random Forest, Logistic Regression, and Gradient Boosting. By applying it, performance comparison for a total of 10 models was conducted. The model with the highest performance was the Gradient Boosting method using TF-IDF Vector input data, and the accuracy was 97%. Therefore, the recommendation system proposed in this study is expected to recommend urban regeneration types based on the regional characteristics of new business sites in the process of carrying out urban regeneration projects."

• Journal of The Korean Association For Science Education
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• v.32 no.2
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• pp.306-319
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• 2012

The purpose of this study was to investigate high school students' learning style, perception of types of laboratory instruction, and the relationship between the learning style and preferred type of laboratory instruction. The participants of this study were 19 female high school students, from Incheon in Korea, who showed outstanding science grades. Dunn et al's revised Learning Styles Inventory (1997) was used for testing students' learning style. The students were asked to choose preferred and not preferred types of experiments and describe the reason of the choices after implementation of 4 types of experiments: verification, discovery, explorator, and investigation laboratory instructions. The findings of this study were as follows: Firstly, the students had a certain common learning style irrelevant to their personal characteristics, i. e; they showed high (self, teacher, parents) motivation and structure stimuli that was common in Korean students. Second, outstanding students prefer unstructured and open laboratory instructions. And those students were highly influenced by sociological and emotional stimuli. Third, students' learning style was related to their preferred type of laboratory instruction. Students preferring unstructured and open laboratory were influenced by sociological and emotional stimuli, while those preferring structured and closed laboratory were influenced by physiological stimuli.

• Journal of Korean Society of Transportation
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• v.25 no.3
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• pp.87-97
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• 2007

This paper proposes drivers' rational belief formation under a bounded traffic environment. This is to escape the criticism that excessive rationality (e.g., a driver's calculating ability and memory capacity) is required of drivers. Under bounded traffic environments. drivers do not have structural knowledge of traffic conditions and others' decisions. Simulations are carried out using a program coded in C. Consequently, the author found the learning process of drivers and the value of information can be differentiated by route conditions and the characteristics of driver groups. Also, it was found that rational drivers form different beliefs about traffic conditions even though they have the same traffic environment in a bounded traffic environment.

• Hwankyungkyoyuk
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• v.16 no.1
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• pp.25-33
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• 2003

This study aimed to discern the educational meaning of nature experience activity in a nonformal educational program in Korea, focusing on the interaction between a teacher and learners. To achieve this objective, an ethnographic research method was employed using an environmental educational program for children in a nonformal setting. The results of study are as followings. Firstly, the teacher's belief-"young ecologist" shaped its own characteristics of the program. Secondly, the children had a understanding that they learn something about nature(e.g. learning by seeing, dlscovering, recollecting, and awakening). The analysis of teachers' ideas and learners' attitude toward nature experience shows that there exists a gap between the teachers' expectations and the actual ecological changes in the learners' ideas. However, the educational meaning of nature experience can be understood by the unique type of interaction between a teacher and learners. In conclusion, on the basis of this study, it is suggested that educators should be aware of the fact that nature experience can conttribute significantly to the education of children not just from the encounter with nature but also philosophically with regard to our connectedness with nature. Bringing nature into educational contexts can help children to take part in thoughtful perspectives of learning and to devise their own appropriate nature experience.