• Journal of The Korean Association For Science Education
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• v.39 no.3
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• pp.337-348
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• 2019

The purpose of this study is to examine epistemic thinking in middle school students in an argument-based inquiry science class. Participants of the study were 93 9th grade students from four classes of a middle school in a metropolitan city. Observations were made over one semester during which argument-based inquiry lessons on five subjects were conducted. Data was collected from argument-based inquiry activity worksheets and student questionnaires. After analysis of epistemic thinking in the written reflections, students were found to have the highest frequency of epistemic metacognitive skills, followed by epistemic cognition, epistemic metacognitive experience, and epistemic metacognitive knowledge. While investigating the effects of an argument-based inquiry science class on student epistemic thinking and after analysis of the reflections written for the first ABI activity and the fifth ABI activity, we found that all of the sub-elements of epistemic thinking have increased. The rate of growth for epistemic cognition is greatest, followed by epistemic metacognitive knowledge and epistemic metacognitive skills. Assessed for epistemic thinking, the level of epistemic thinking improved over the course of the argument-based inquiry science class. The results of the survey show that students actively participating and being recognized for their active participation in the argument-based inquiry science class are helpful in understanding scientific knowledge. Therefore, an argument-based inquiry science class is a teaching and learning program that allows students to understand and experience the epistemic nature of scientific knowledge and its construction through collaboration and agreement.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.38 no.6
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• pp.839-850
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• 2018

The flood damage in urban areas due to torrential rain is increasing with urbanization. For this reason, accurate and rapid flooding forecasting and expected inundation maps are needed. Predicting the extent of flooding for certain rainfalls is a very important issue in preparing flood in advance. Recently, government agencies are trying to provide expected inundation maps to the public. However, there is a lack of quantifying the extent of inundation caused by a particular rainfall scenario and the real-time prediction method for flood extent within a short time. Therefore the real-time prediction of flood extent is needed based on rainfall-runoff-inundation analysis. One/two dimensional model are continued to analyize drainage network, manhole overflow and inundation propagation by rainfall condition. By applying the various rainfall scenarios considering rainfall duration/distribution and return periods, the inundation volume and depth can be estimated and stored on a database. The Rainfall-Duration-Flooding Quantity (RDF) relationship curve based on the hydraulic analysis results and the Self-Organizing Map (SOM) that conducts unsupervised learning are applied to predict flooded area with particular rainfall condition. The validity of the proposed methodology was examined by comparing the results of the expected flood map with the 2-dimensional hydraulic model. Based on the result of the study, it is judged that this methodology will be useful to provide an unknown flood map according to medium-sized rainfall or frequency scenario. Furthermore, it will be used as a fundamental data for flood forecast by establishing the RDF curve which the relationship of rainfall-outflow-flood is considered and the database of expected inundation maps.

• Journal of Navigation and Port Research
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• v.42 no.6
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• pp.539-545
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• 2018

In recent years, research on shipping market forecasting with the employment of non-linear AI models has attracted significant interest. In previous studies, input variables were selected with reference to past papers or by relying on the intuitions of the researchers. This paper attempts to address this issue by applying the stepwise regression model and the random forest model to the Cape-size bulk carrier market. The Cape market was selected due to the simplicity of its supply and demand structure. The preliminary selection of the determinants resulted in 16 variables. In the next stage, 8 features from the stepwise regression model and 10 features from the random forest model were screened as important determinants. The chosen variables were used to test both models. Based on the analysis of the models, it was observed that the random forest model outperforms the stepwise regression model. This research is significant because it provides a scientific basis which can be used to find the determinants in shipping market forecasting, and utilize a machine-learning model in the process. The results of this research can be used to enhance the decisions of chartering desks by offering a guideline for market analysis.

• Journal of the Korean earth science society
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• v.40 no.2
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• pp.188-199
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• 2019

The purpose of this study was to investigate the tendency of inquiry of earth science content presented in North Korean textbooks of the 2013 National curriculum using Romey's method, and to help use as basic data for better understanding earth science education in North Korea. The content of earth science in the text, figure, question, and activity index of textbooks of Natural Science 1 and 2, Chosun Geography 2 of elementary junior high school, and of Geography 1 of advanced junior high school were all analyzed using Romey's method. The results of this study were as follows: First, the atmospheric science question and the astronomy text showed the tendency of inquiry type. Second, the proportion of oceanography was relatively small. Third, there were many non-inquiry questions or excessive inquiry questions, and both types of questions needed to be balanced. Fourth, there were a tendency that did not emphasize inquiry learning. Finally, the quantitative and qualitative level of inquiry tendency should be improved. In this paper, we propose to use a qualitative method when analyzing earth science content in North Korean textbooks, and suggested that we should further study the comparative analysis of inquiry tendency of earth science content using South and North Korean textbooks.

• Korean Journal of Remote Sensing
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• v.35 no.2
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• pp.299-316
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• 2019

The purpose of this study was to analyze landslide susceptibility in the Pyeongchang area using Weight of Evidence (WOE) and Evidential Belief Function (EBF) as probability models and Artificial Neural Networks (ANN) as a machine learning model in a geographic information system (GIS). This study examined the widespread shallow landslides triggered by heavy rainfall during Typhoon Ewiniar in 2006, which caused serious property damage and significant loss of life. For the landslide susceptibility mapping, 3,955 landslide occurrences were detected using aerial photographs, and environmental spatial data such as terrain, geology, soil, forest, and land use were collected and constructed in a spatial database. Seventeen factors that could affect landsliding were extracted from the spatial database. All landslides were randomly separated into two datasets, a training set (50%) and validation set (50%), to establish and validate the EBF, WOE, and ANN models. According to the validation results of the area under the curve (AUC) method, the accuracy was 74.73%, 75.03%, and 70.87% for WOE, EBF, and ANN, respectively. The EBF model had the highest accuracy. However, all models had predictive accuracy exceeding 70%, the level that is effective for landslide susceptibility mapping. These models can be applied to predict landslide susceptibility in an area where landslides have not occurred previously based on the relationships between landslide and environmental factors. This susceptibility map can help reduce landslide risk, provide guidance for policy and land use development, and save time and expense for landslide hazard prevention. In the future, more generalized models should be developed by applying landslide susceptibility mapping in various areas.

• Journal of Technology Innovation
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• v.27 no.1
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• pp.45-77
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• 2019

The balance between exploration for new possibility and exploitation for existing certainty is an important issue in strategy, innovation, R&D as well as organization learning. Among the convergence trends of technologies, many firms seek to have the wider technological knowledge assets and the deeper technology capabilities for the sustainable competitive advantage at the same time. While firms plan technology portfolio strategies, they should consider the attribute of the technology. Nanotechnology, a cutting-edge technology, is a general purpose technology, unlike conventional product-oriented technologies. This empirical study was focused on how multi-national firms' exploration and exploitation strategies for nanotechnology affect their innovative and financial performance. It uses multiple regression analysis on panel data. This result shows that the more diversified and specialized nanotechnology as platform technology is positively related to their innovative and financial performance, unlike the research results for product-oriented technologies. In addition, exploratory innovation is more effective to firm performance than exploitation. This implies how global firms can manage effectively platform technology strategies under the constraints of resources.

• Journal of the Korean earth science society
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• v.40 no.3
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• pp.300-312
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• 2019

The purpose of this study is to develop an astronomical observing education program that enables high school students to inquire the distance of astronomical bodies based on the research methods (observing open clusters and exploring collected big data) using small telescopes and DSLR cameras. After analyzing the 2015 revised science curriculum, we developed science club activity materials and teacher-student learning contents suitable for high school earth science education. A panel of six teachers and researchers of earth science education and astronomy, participated in developing the educational materials. The validity of the program was verified through establishing the agreement among the panels after in-depth discussions and clarifications. The program, developed with 10 lessons in total, showed high satisfactory content validity (CVI, .89) and conformity of school class (Likert's 5 point scales, 4.17). The feedback of the panels and the Delphi analysis continued to improve the quality of the program. The pilot testing result with high school students (N=9) showed that the students' satisfaction rate was high as 4.48. Using the astronomical observational education program of this study is expected to contribute in improving the convergence educational activity, interest, curiosity, and inquiry ability of students in the universe and the astronomical bodies.

• Korean Journal of Child Education & Care
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• v.19 no.2
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• pp.19-33
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• 2019

Objective: The purpose of this study is to understand how the experience of studying mathematics education for young children based on picture books is affecting pre-service early childhood teachers with their attitude toward mathematics and mathematics teaching efficiency. Methods: For this, a total of 39 pre-service early childhood teachers majoring in early childhood education at S university located in G metropolitan city participated in the study. 20 of them are randomly assigned to the experimental group while the rest 19 were assigned to the control group. The experimental group participated in the classes of mathematics education for young children based on picture books for 15 weeks, while the control group attended the normal classes of mathematics education for young children for the same period of time. By using SPSS 18.0 Program for the collected data, t-test was conducted for differences in the results of attitude toward mathematics and mathematics teaching efficiency. Results: The results of this study are as follows. Firstly, the experience of studying mathematics education for young children based on picture books had a positive effects on pre-service early childhood teachers' attitude toward mathematics, improved values and interest in mathematics, and reduced anxiety about mathematics. Secondly, the experience of studying mathematics education for young children based on picture books had a positive effects on improving pre-service early childhood teachers' mathematics teaching efficiency. Also, both faith in ability and faith in results have improved significantly. Conclusion/Implications: These results imply that the experience of studying mathematics education for young children based on picture books is an effective teaching-learning method in improving pre-service early childhood teachers' attitude toward mathematics and mathematics teaching efficiency.

• Journal of the Korean Society of Earth Science Education
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• v.12 no.2
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• pp.119-130
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• 2019

The TIMSS assessment is conducted every four years, and Korean fourth grade cohort in TIMSS 2011 participated in TIMSS 2015 again as eighth graders, which produced the first achievement data of the cohort group of elementary and middle schools. In this study, in order to investigate the causes of the decline in Korean students' science achievement with grade changes from the fourth to the eighth grade, we analyzed educational context variables such as characteristics of students, teachers, and classroom instructions of the top 5 achievement countries participated in both TIMSS 2011 and TIMSS 2015. According to the results, students' sense of school belonging increased, whereas students' positive attitudes toward science teaching decreased with the grade change from the fourth to the eighth. As for the teacher characteristics, the teacher's professional development activity increased, and the teacher's confidence in science teaching showed similar tendency to the international average. Regarding classroom instruction characteristics, the frequency of inquiry-related science activities was highest at the fourth grade, and lower than the international average at the eighth grade. Based the results, we suggested implications for science teaching and learning as well as further studies including development of differentiated strategy by the school level to improve students' achievement, the necessity of converting into more student-engaging science classes, and the necessity of in-depth study on the teacher related educational contextual variables.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.18 no.5
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• pp.91-99
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• 2019

Existing node-to-node based optimal path searching is built on the assumption that all destination nodes can be arrived at from an origin node. However, the recent appearance of the adaptive path search algorithm has meant that the optimal path solution cannot be derived in node-to-node path search. In order to reflect transportation data at the links in real-time, the necessity of the node-to-link (or link-to-node; NL) problem is being recognized. This research assumes existence of a network with link-label and non-additive path costs as a solution to the node-to-link optimal path problem. At the intersections in which the link-label has a turn penalty, the network retains its shape. Non-additive path cost requires that M-similar paths be enumerated so that the ideal path can be ascertained. In this, the research proposes direction deletion and turn restriction so that regulation of the loop in the link-label entry-link-based network transformation method will ensure that an optimal solution is derived up until the final link. Using this method on a case study shows that the proposed method derives the optimal solution through learning. The research concludes by bringing to light the necessity of verification in large-scale networks.