• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.7
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• pp.120-128
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• 2019

It is very important to verify the seismic performance and stability of the power plant fixture in the domestic power plant, because earthquakes have increased in frequency around the world which resulted in the frequent occurrence of power plant damage caused by the failure of electric power facilities. In this study, through the on-site inspection of power plant fixation unit installed in domestic power plants, we carried out structural performance evaluation of the fixation unit anchor bolts installed on the concrete slabs. The field survey showed M12 J hook anchor bolts were used. Anchor bolt pullout and shear performance evaluation were performed based on ASTM E 488-96 standard. Moreover, artificial crack with the width of 0.5 mm was applied during the experiment based on ATM355.4 and ETAG 001. The comparison of M12 J hook anchor bolt pullout and shear test result to design value required in domestic and international design standard, show a satisfactory result. M12 J hook anchor pullout and shear performance was found to be about 35% and 7%, respectively, higher than the required design value.

• Journal of Technology Innovation
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• v.24 no.4
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• pp.101-126
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• 2016

This paper identifies core research topics and their relationships by deriving the research topic networks in the technology management field using co-word analysis. Contrary to the conventional approach in which undirected networks are constructed based on normalized co-occurrence frequency, this study analyzes directed networks of keywords by employing the confidence index of association rule mining for pairs of keywords. Author keywords included in 2,456 articles published in nine international journals of technology management in 2011~2014 are extracted and categorized into three types: THEME, METHOD, and FIELD. One-mode networks for each type of keywords are constructed to identify core research keywords and their interrelationships with each type. We then derive the two-mode networks composed of different two types of keywords, THEME-METHOD and THEME-FIELD, to explore which methods or fields are frequently employed or studied for each theme. The findings of this study are expected to be fruitfully referred for researchers in the field of technology management to grasp research trends and set the future research directions.

• Journal of the Korean Data and Information Science Society
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• v.28 no.4
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• pp.811-818
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• 2017

Environmental tests are used to verify a equipment that can withstand the rigors of harsh environments. In case of military products for export, the tests have to be based on the climatic data of the world. However, if the climatic data of the world is used for domestic military products, it may cause an increase in manufacture price. There is currently no climatic data that can be used as criteria for the tests in the Korean peninsula and coastal seas. Therefore, this paper suggests a water temperature and a salinity guidelines of salt fog tests for military products used in the area. As a result, we present water temperature and salinity information that is extreme and FOO of the Korean coastal seas.

• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.733-746
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• 2021

Purpose: This study was conducted for the purpose of selecting important events from among various events that may pose a risk to railway passengers. For this purpose, opinions of various railroad vehicle passengers and railway operator workers were investigated and analyzed. Method: The survey was conducted on 1,000 men and women in their 20s and 60s and 429 workers at 11 company across the country. A survey was conducted on the dangerous situations that may occur in subways, general railroads and high-speed rail vehicles targeting passengers. For railway operator workers, the questionnaire is limited to subway vehicles. Result: Among the passenger risk factors(abnormal behavior and dangerous situations) selected based on the frequency and importance of occurrence of passenger risk factors, the main risk factors are selected 'car door jamming', 'sexual harassment', 'intoxicating behavior', 'fighting' /assault', 'wandering around', and 'not wearing a mask'. Conclusion: The major risk factors affecting passengers were selected by surveying passengers and railway operators. we plan to develop a CCTV detection system with AI technology that can quickly and continuously detect the major risk factors of railway vehicles selected as a result of this study.

• Journal of Intelligence and Information Systems
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• v.29 no.2
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• pp.267-283
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• 2023

The COVID-19 pandemic, which began in December 2019 and continues to this day, has left the public needing information to help them cope with the pandemic. However, COVID-19-related fake news on social media seriously threatens the public's health. In particular, if fake news related to COVID-19 is massively spread with similar content, the time required for verification to determine whether it is genuine or fake will be prolonged, posing a severe threat to our society. In response, academics have been actively researching intelligent models that can quickly detect COVID-19-related fake news. Still, the data used in most of the existing studies are in English, and studies on Korean fake news detection are scarce. In this study, we collect data on COVID-19-related fake news written in Korean that is spread on social media and propose an intelligent fake news detection model using it. The proposed model utilizes the frequency information of parts of speech, one of the linguistic characteristics, to improve the prediction performance of the fake news detection model based on Doc2Vec, a document embedding technique mainly used in prior studies. The empirical analysis shows that the proposed model can more accurately identify Korean COVID-19-related fake news by increasing the recall and F1 score compared to the comparison model.

• Journal of Soil and Groundwater Environment
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• v.10 no.1
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• pp.65-74
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• 2005

National groundwater monitoring stations have been managed throughout the country by Korea Water Resources Corporation (KOWACO) in order to monitor variations in quantity and quality of groundwater resources. A multi-sensor installed in each monitoring station well measures groundwater level, water temperature and electrical conductivity every six hours and the logged data are automatically transmitted to a host computer in KOWACO. Meanwhile despite regular station inspection and replacement of deteriorate or broken devices, abnormal values or outliers often occur due to intrinsic limitations of automatic monitoring and transmission. Thus prompt recognition and measures to these values are essentially required to reduce disturbance and missing period of the data. In this study, time and frequency of outlier occurrence were analyzed for the water level data obtained from national groundwater monitoring stations within the Han river basin in 2000. The analysis results indicated that the most prominent patterns of the outliers were rapid decline for water level, no variation for temperature and steep decline for electrical conductivity. This study provided a sample criterion for determining the outlier for each parameter.

• Journal of the Korean School Mathematics Society
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• v.24 no.1
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• pp.107-126
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• 2021

Lexicon is closely related to human thinking. In particular, a classroom lexicon results from objectifying the teaching-learning activity in classrooms, allowing humans to recognize and explore the activities and phenomena in classrooms explicitly. Therefore, using the lexicon and clarifying what the words mean is to enhance the understanding of teaching activities. The International Classroom Lexicon Project investigates and identifies each country's mathematics classroom lexicon, where ten countries participated. The purpose of this current study is to compare the differences in perceptions between teachers and pre-service teachers about the Korean classroom lexicon previously investigated as a part of the international collaborative project. By comparing the responses of 147 teachers and 127 pre-service teachers, the degree of familiarity with pedagogical terms and the frequency of occurrence or usage in classrooms were compared and analyzed to understand the recognition of pre-service teachers' pedagogical terms. Finally, we also discuss reflections on Korean mathematics teaching practices in Korea.

• Convergence Security Journal
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• v.22 no.5
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• pp.95-105
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• 2022

The Army, Navy, and Air Force are making various efforts to develop a weapon system that incorporates the 4th industrial revolution technology so that it can be used in multi-domain operations. In order to effectively demonstrate the integrated combat power through the weapon system to which the new technology is applied, it is necessary to establish a network environment in which each weapon system can transmit and receive information smoothly. For this, it is essential to analyze the Information Exchange Requirement(IER) of each weapon system, but many IER analysis studies did not sufficiently reflect the various considerations of the actual tactical network. Therefore, this study closely analyzes the research methods and results of the existing information exchange requirements analysis studies. In IER analysis, the size of the message itself, the size of the network protocol header, the transmission/reception structure of the tactical network, the information distribution process, and the message occurrence frequency. In order to be able to use it for future IER prediction, we present a technique for calculating the information exchange requirement as a probability distribution using the Poisson distribution and the probability generating function. In order to prove the validity of this technique, the results of the probability distribution calculation using the message list and network topology samples are compared with the simulation results using Network Simulator 2.

• Journal of Intelligence and Information Systems
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• v.20 no.1
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• pp.195-211
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• 2014

Cloud computing services provide IT resources as services on demand. This is considered a key concept, which will lead a shift from an ownership-based paradigm to a new pay-for-use paradigm, which can reduce the fixed cost for IT resources, and improve flexibility and scalability. As IT services, cloud services have evolved from early similar computing concepts such as network computing, utility computing, server-based computing, and grid computing. So research into cloud computing is highly related to and combined with various relevant computing research areas. To seek promising research issues and topics in cloud computing, it is necessary to understand the research trends in cloud computing more comprehensively. In this study, we collect bibliographic information and citation information for cloud computing related research papers published in major international journals from 1994 to 2012, and analyzes macroscopic trends and network changes to citation relationships among papers and the co-occurrence relationships of key words by utilizing social network analysis measures. Through the analysis, we can identify the relationships and connections among research topics in cloud computing related areas, and highlight new potential research topics. In addition, we visualize dynamic changes of research topics relating to cloud computing using a proposed cloud computing "research trend map." A research trend map visualizes positions of research topics in two-dimensional space. Frequencies of key words (X-axis) and the rates of increase in the degree centrality of key words (Y-axis) are used as the two dimensions of the research trend map. Based on the values of the two dimensions, the two dimensional space of a research map is divided into four areas: maturation, growth, promising, and decline. An area with high keyword frequency, but low rates of increase of degree centrality is defined as a mature technology area; the area where both keyword frequency and the increase rate of degree centrality are high is defined as a growth technology area; the area where the keyword frequency is low, but the rate of increase in the degree centrality is high is defined as a promising technology area; and the area where both keyword frequency and the rate of degree centrality are low is defined as a declining technology area. Based on this method, cloud computing research trend maps make it possible to easily grasp the main research trends in cloud computing, and to explain the evolution of research topics. According to the results of an analysis of citation relationships, research papers on security, distributed processing, and optical networking for cloud computing are on the top based on the page-rank measure. From the analysis of key words in research papers, cloud computing and grid computing showed high centrality in 2009, and key words dealing with main elemental technologies such as data outsourcing, error detection methods, and infrastructure construction showed high centrality in 2010~2011. In 2012, security, virtualization, and resource management showed high centrality. Moreover, it was found that the interest in the technical issues of cloud computing increases gradually. From annual cloud computing research trend maps, it was verified that security is located in the promising area, virtualization has moved from the promising area to the growth area, and grid computing and distributed system has moved to the declining area. The study results indicate that distributed systems and grid computing received a lot of attention as similar computing paradigms in the early stage of cloud computing research. The early stage of cloud computing was a period focused on understanding and investigating cloud computing as an emergent technology, linking to relevant established computing concepts. After the early stage, security and virtualization technologies became main issues in cloud computing, which is reflected in the movement of security and virtualization technologies from the promising area to the growth area in the cloud computing research trend maps. Moreover, this study revealed that current research in cloud computing has rapidly transferred from a focus on technical issues to for a focus on application issues, such as SLAs (Service Level Agreements).

• Korean Journal of Weed Science
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• v.1 no.1
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• pp.78-83
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• 1981

This study was attempted to determine the major weed species occurring in Korean turfgrass, Zoysia japonica Steud. and to evaluate the most effective means for controlling them. More or less 40 weed species were determined to occur in Korean turfgrass. In terms of quantity and frequency of occurrence, Trifolium repens L., Digitaria sanguinalis (L.) Scop., Draba nemorosa var. hebecarpa Lindbl, Erigeron canadensis L., and Cyperus amuricus Max were observed to be the major weeds. Simpson's index, 0.306 was obtained to be the major weeds. Simpson's index, 0.306 was obtained in the golf course, Jinryang, Gyungsan-gun, meaning that no specific weed species were dominant, but in Kyungpook National University campus, Trifolium repense L. was a single dominant species, indicating Simpson's index, 0.776. The most effective herbicides to control Trifolium repense L. and other broad leaf weeds were MCPP [2-(2-methyl-4-chlorophenoxy) propionic acid), followed by 2,4-D (2,4-dichlolophenoxy acetic acid). Increased rates of both herbicides increased markedly their effectivity against weeds, with very slight injury against turfgrass. MCPP at 2.8 kg(a.i.)/ha gave excellent control without any injury and 2,4-D at 1.0 kg(a.i.)/ha.