• Journal of the Korean Chemical Society
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• v.63 no.5
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• pp.376-386
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• 2019

The purpose of this study was to explore the learning progression of logical thinking in acid and base chemical reactions and to evaluate its validity. For this purpose, we collected 387 participants in 9 schools of elementary, middle and high schools nationwide. The questionnaire developed in this study was composed of nine items. The questionnaire presented the acid and base reactants and products, and the students pictured their thoughts on how these substances change, and answered the reasons of their thoughts. Situation contexts of the questionnaire were divided into two groups: one kind of solute dissolved in a solvent, and two kinds of solute dissolved in a solvent. In this study, six levels of learning progression were assumed by combining material conservation logic, combination logic, proportion logic, and particle number conservation logic. By analyzing the data, Infit and Outfit values of Person reliability, Item reliability, MNSQ and ZSTD were obtained from the Rasch model. As a result of the analysis of data, it was found that lower levels of learning progression prevailed up to the younger grade students till $8^{th}$ grade. The higher levels of learning progression(Level 2~Level 5) prevailed up to the older grade students. However, higher levels of learning progression dropped sharply in Grade 12. The 5 level of learning progression was very low in all grades, and $9^{th}$ grade had highest percentage of students belonging to the 5 level. Interpretation of these unusual results suggests a future research related to explanation differences of textbooks.

• Journal of Internet Computing and Services
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• v.22 no.2
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• pp.29-39
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• 2021

As damages to individuals, private sectors, and businesses increase due to newly occurring cyber attacks, the underlying network security problem has emerged as a major problem in computer systems. Therefore, NIDS using machine learning and deep learning is being studied to improve the limitations that occur in the existing Network Intrusion Detection System. In this study, a deep learning-based NIDS model study is conducted using the Convolution Neural Network (CNN) algorithm. For the image classification-based CNN algorithm learning, a discrete algorithm for continuity variables was added in the preprocessing stage used previously, and the predicted variables were expressed in a linear relationship and converted into easy-to-interpret data. Finally, the network packet processed through the above process is mapped to a square matrix structure and converted into a pixel image. For the performance evaluation of the proposed model, NSL-KDD, a representative network packet data, was used, and accuracy, precision, recall, and f1-score were used as performance indicators. As a result of the experiment, the proposed model showed the highest performance with an accuracy of 85%, and the harmonic mean (F1-Score) of the R2L class with a small number of training samples was 71%, showing very good performance compared to other models.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.39-57
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• 2021

In this study, mathematical analysis is conducted by focusing to the 'size' of the 'point' and the 'line'. The textbook descriptions of the 'point' and the 'line' in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum and US geometry textbooks were compared and analyzed between. First, as a result of mathematical analysis of' 'the size of a point and a segment', it was found that the mathematical perspectives could be different according to 1) the size of a point is based on the recognition and exclusion of 'infinitesimal', and 2) the size of the segment is based on the 'measure theory' and 'set theory'. Second, as a result of analyzing textbook descriptions of the 'point' and the 'line', 1) in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum, after presenting a learning activity that draws a point with 'physical size' or line, it was developed in a way that describes the 'relationship' between points and lines, but 2) most of the US geometry textbooks introduce points and lines as 'undefined terms' and explicitly states that 'points have no size' and 'lines have no thickness'. Since the description of points and lines in the geometry content area of middle school mathematics 1 by the 2015 revised Korean mathematics curriculum may potentially generate mathematical intuitions that do not correspond to the perspective of Euclid geometry, this study suggest that attention is needed in the learning process about points and lines.

• Korean Journal of Construction Engineering and Management
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• v.20 no.4
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• pp.34-45
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• 2019

To drive construction project successful, a construction manager with good competency is needed. In order to select appropriate construction manager, there should be a standard and a method for appropriately evaluating the competency of construction manager. There have been many researches on the competency of construction managers, but there are two points to be supplemented. One is that construction manager's competency measurement was not concrete and objective, and the other is that construction project performance directly reflects individual manager's performance. The purpose of this study is to derive a construction manager competency evaluation index by using the Notational Analysis technique that is used when deriving an indicator that measures the athlete's competency in sports. This analysis was drawn with Delphi method. Finally, the 'measurable behaviors'were derived that can evaluate the competency of construction managers. Through this, it is possible to express each manager's expertise, leadership, and personal characteristics in numerical expression. This will help decision makers when selecting construction managers. It is anticipated that decision makers will be able to make the decision to select the necessary construction managers easier because it can evaluate the construction managers through a scientific approach based on the record by supplementing the existing method which only relied on intuition.

• Journal of Korea Water Resources Association
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• v.52 no.6
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• pp.429-440
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• 2019

The numbers of multi-year droughts due to climate change are increasing worldwide. Boryeong Dam, located in Chungcheongnam-do, South Korea, was also affected by a 4-year drought from 2014 to 2017. Since traditional unilateral decision making processes to alleviate drought damage have, until now, resulted in conflicts between many of the involved groups, the need for active participation from both stakeholders and policymakers is greater than before. This study introduced Shared Vision Planning, a collaborative decision making process that involves participation from various groups of stakeholders, by organizing Water Policy Council for Climate Change Adaptation in Chungcheongnam-do. A Shared Vision Planning Model was then developed with a system dynamics software by working together with relevant stakeholders to actively reflect their requests through three council meetings. Multiple simulations that included various future climate change scenarios were conducted, and future drought vulnerability analysis results of Boryeong Dam and districts, in terms of frequency, length, and magnitude, were arrived at. It was concluded that Boryeong Dam was more vulnerable to future droughts than the eight districts. While the total water deficit in the eight districts was not so significant, their water deficit in terms of spatial discordance was proved to be more problematic. In the future, possible alternatives to the model will be implemented so that stakeholders can use it to agree on a policy for possible conflict resolutions.

• Cross-Cultural Studies
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• v.40
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• pp.91-110
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• 2015

Both Plato and More imagined alternative ways of organizing society. What is common to both authors, then, is the fact that they resorted to fiction to discuss other options. They differed, however, in the way they presented that fiction. The concept of utopia is no doubt an attribute of modern thought, and one of its most visible consequences. But one of the main features of utopia as a literary genre is its relationship with reality. Utopists depart from the observation of the society they live in, note down the aspects that need to be changed and imagine a place where those problems have been solved. After the two World Wars, the twentieth century was predominantly characterized by man's disappointment at the perception of his own nature. In this context, utopian ideals seemed absurd and the floor was inevitably left to dystopian discourse. Both The Road by Cormac MacCarthy and The Childhood of Jesus by J. M. Coetzee can be called critical dystopia and critical utopia as they represent the imaginary place and time that author intended a contemporaneous reader to view as better or worse than contemporary society but with difficult problems that the described society may or may not be able to solve. As a changed adventure narrative, they have something in common like open ending, father and son relationship and religious allegory. But the most important thing is that they express the utopian impulse that is still energetic and transforming in the post-modern society.

• Journal of the HCI Society of Korea
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• v.14 no.1
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• pp.5-13
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• 2019

SNS has been advanced from first to third generation by changing its service format in various ways. Nowadays, image-based SNS such as instagram and pinterest where users communicate via images has become popular as third generation service. Due to the fact that users communicate especially through images, image-based SNS utilizes images in different ways compared to other SNS. This study derived various characteristics of images in image-based SNS, and observed how users perceive each of them differently. Also, relationship between the characteristics and user satisfaction on image-based SNS is analyzed. The characteristics include 6 items; 'implicity', 'recordability', 'expressing identity', 'indirect experience', 'temporary amusement', and 'stimulating desire.' As a result of comparing user perception regarding those 6 characteristics, recordability and indirect experience were highly recognized than other characteristics. Also, according to users' age, motivation of using image-based SNS, and number of followers they have, users perceived each characteristic in different level. Finally, relationship between the characteristics and user satisfaction was analyzed, and the result showed that indirect experience had positive influence to user satisfaction. Regarding indirect experience, it was highly perceived by users and also had positive influence to their satisfaction, which means it is the most typical characteristic of image-based SNS.

• Journal of the Korean Institute of Landscape Architecture
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• v.47 no.3
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• pp.71-80
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• 2019

The Fourth Industrial Revolution, centered on intelligence and information, began to take hold in 2016. This study uses virtual reality technology, which is the most popular technology of the Fourth Industrial Revolution. The purpose of this study is to explore a Virtual Walk-through method, which can be easily applied to landscape architecture. At present, virtual reality technology is widely used in the fields of games, emergency training, and architectural design. However, in the field of landscape architecture, it is still in the development stage. In addition, most of the traditional ways to display virtual reality use 2D images, but such methods have some limitations. Therefore, this research addresses the three stages of "design-exhibition-experience" and puts forward a new simple method called 'Virtual Walk-through' that breaks from traditional landscape design exhibitions. The results show that compared with traditional methods, virtual reality has many advantages, such as the freedom of experience, a diversity of viewing angles, information supply, interaction, etc. It can show high quality images and effects, which are suitable for landscape design. It provides an evaluation method for garden design that can be utilized in the future. It is simple and has value as it can reflect the method and the expected effects. Virtual reality technology can bring an infinite number of prospects to the development of landscape architecture.

• Journal of the Korean School Mathematics Society
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• v.24 no.2
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• pp.173-190
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• 2021

This study analyzed the proof of the inverse square law, which is said to be the core of Newton's , in relation to the geometric limit. Newton, conscious of the debate over infinitely small, solved the dynamics problem with the traditional Euclid geometry. Newton reduced mechanics to a problem of geometry by expressing force, time, and the degree of inertia orbital deviation as a geometric line segment. Newton was able to take Euclid's geometry to a new level encompassing dynamics, especially by introducing geometric limits such as parabolic approximation, polygon approximation, and the limit of the ratio of the line segments. Based on this analysis, we proposed to use Newton's geometric limit as a tool to show the usefulness of mathematics, and to use it as a means to break the conventional notion that the area of the curve can only be obtained using the definite integral. In addition, to help the desirable use of geometric limits in school mathematics, we suggested the following efforts are required. It is necessary to emphasize the expansion of equivalence in the micro-world, use some questions that lead to use as heuristics, and help to recognize that the approach of ratio is useful for grasping the equivalence of line segments in the micro-world.

• Journal of Cadastre & Land InformatiX
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• v.51 no.1
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• pp.39-51
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• 2021

Recently, there has been much interest in practical use of standardized HD map that can effectively define roads, lanes, junctions, road signs, and road facilities in autonomous driving. Various kinds of de jure or de facto standards such as ISO 22726-1, ISO 14296, HERE HD Live map, NDS open lane model, OpenDRIVE, and NGII HD map are currently being used. However, there are lots of differences in data modeling among these standards, it makes difficult to use them together in autonomous driving. Therefore, we propose a data model conversion method to enable an efficient use of various kinds of HD map standards in autonomous driving in this study. Specifically, we propose a conversion method between the NGII HD map model, which is easily accessible in the country, and the OpenDRIVE model, which is commonly used in the autonomous driving industry. The proposed method consists of simple conversion of NGII HD map layers into OpenDRIVE objects, new OpenDRIVE objects creation corresponding to NGII HD map layers, and linear transformation of NGII HD map layers for OpenDRIVE objects creation. Finally, we converted some test data of NGII HD map into OpenDRIVE objects, and checked the conversion results through Carla simulator. We expect that the proposed method will greatly contribute to improving the use of NGII HD map in autonomous driving.