• Computers and Concrete
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• v.24 no.6
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• pp.527-539
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• 2019

In this paper, the fracture characteristics of concrete specimens with different notch depths under three-point flexural loads are studied by finite element and fracture mechanics methods. Firstly, the concrete beams (the size is 700×100×150 mm) with different notch depths (a=30 mm, 45 mm, 60 mm and 75 mm respectively) are tested to study the influence of notch depths on the mechanical properties of concrete. Subsequently, the concrete beams with notch depth of 60 mm are loaded at different loading rates to study the influence of loading rates on the fracture characteristics, and digital image correlation (DIC) is used to monitor the strain nephogram at different loading rates. The test results show that the flexural characteristics of the beams are influenced by notch depths, and the bearing capacity and ductility of the concrete decrease with the increase of notch depths. Moreover, the peak load of concrete beam gradually increases with the increase of loading rate. Then, the fracture energy of the beams is accurately calculated by tail-modeling method and the bilinear softening constitutive model of fracture behavior is determined by using the modified fracture energy. Finally, the bilinear softening constitutive function is embedded into the finite element (FE) model for numerical simulation. Through the comparison of the test results and finite element analysis, the bilinear softening model determined by the tail-modeling method can be used to predict the fracture behavior of concrete beams under different notch depths and loading rates.

• Convergence Security Journal
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• v.18 no.3
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• pp.133-140
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• 2018

As the core technology of the 4th Industrial Revolution is applied to drone, the potential for growth in the field of unmanned aerial vehicles is very large, and the utilization of civilian & military fields in the domestic & foreign is increasing rapidly. Because application areas of drone in the civilian field is various, it is excellent in terms of cost effectiveness and high value in utilization when it is used for military operation support mission. Especially, in the case of the Air Force, it is expected that military usage effectiveness will be high if drone replaces various air operations support missions such as aircraft inspection, supply of military supplies, base security. We find out the missions that can utilize drones for military operations support and propose the recommendation and data management plan accordingly. We recommend the most suitable drones and equipment that perform similar missions in the private sector and propose the data modeling of relational database.

• Journal of Information Technology Services
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• v.21 no.1
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• pp.163-179
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• 2022

Two dominant phenomena in modern world; population ageing and digitalization, have led public sector organizations to heavily rely on B2C(Business-to-Consumer) mobile applications. Yet, fatal concerns and complaints have often been raised by the mobile application users, notably from social welfare sector. With the continual expansion of digital landscape as well as the growth of life expectancy, usage of mobile applications has become prevalent across the stakeholders involved in social welfare sector. 'Smart Long-Term Care (SLTC)', inter alia, is a primary example of such mobile applications, designed to support Long-Term Residential Care (LTRC) service. The main goal of SLTC is to serve more convenient and practical LTRC service for both caregivers and care receivers. To examine user satisfaction of SLTC mobile application, this study investigates existing challenges and means to improve user satisfaction. Hence, we conducted this study using two methods: in-depth interview and topic modeling. Interestingly, two research outcomes commonly indicated that 5 factors (stability, accessibility, usefulness, responsiveness, and ease of use) were found significant in affecting user satisfaction of SLTC. Our findings suggest that the aforementioned factors can be seen as potential causes of the genuinely low user satisfaction. Eventually, this work will be a stepping-stone to elevate the overall quality level of LTRC service along with the user satisfaction degree of SLTC mobile application.

• Journal of Korean Society of Archives and Records Management
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• v.23 no.4
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• pp.91-111
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• 2023

This study aims to analyze research topics within the domain of archival studies by examining bibliographic information from academic papers in archival science, library and information science, and history. After collecting 1,173 academic papers, network analysis was performed based on author keyword data, topic modeling was conducted from abstract data, and the analysis results were organized over time. The network analysis results based on author keywords confirmed that the research topic network actively changed according to variations in major laws and policies. Moreover, topic modeling from the abstract showed that the subjects of the entire academic paper were divided into "Records Management," "Archiving," and "National Records Policy." Notably, from 2002 to 2009, "Records Management" and "National Records Policy" were relatively dominant, but it has achieved balanced quantitative growth since 2009, peaking in 2019.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.1
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• pp.31-48
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• 2024

The domestic automotive industry must consider a strategic shift from traditional automotive component manufacturing to align with future trends such as connectivity, autonomous driving, sharing, and electrification. This research conducted topic modeling on R&D projects in the future automotive sector funded by the Ministry of Trade, Industry, and Energy from 2013 to 2021. We found that topics such as sensors, communication, driver assistance technology, and battery and power technology remained consistently prominent throughout the entire period. Conversely, topics like high-strength lightweight chassis were observed only in the first period, while topics like AI, big data, and hydrogen fuel cells gained increasing importance in the second and third periods. Furthermore, this research analyzed the areas of concentrated investment for each period based on topic-specific government investment amounts and investment growth rates.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.661-670
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• 2021

Research trends can be usefully used to determine the importance of research topics by period, identify insufficient research fields, and discover new fields. In this study, research trends of urban spaces, where various problems are occurring due to population concentration and urbanization, were analyzed by topic modeling. The analysis target was the abstracts of papers listed in the Korea Citation Index (KCI) published between 2002 and 2019. Topic modeling is an algorithm-based text mining technique that can discover a certain pattern in the entire content, and it is easy to cluster. In this study, the frequency of keywords, trends by year, topic derivation, cluster by topic, and trend by topic type were analyzed. Research in urban regeneration is increasing continuously, and it was analyzed as a field where detailed topics could be expanded in the future. Furthermore, urban regeneration is now becoming a regular research field. On the other hand, topics related to development/growth and energy/environment have entered a stagnation period. This study is meaningful because the correlation and trends between keywords were analyzed using topic modeling targeting all domestic urban studies.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.14 no.3
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• pp.184-192
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• 2021

Domestic agriculture is facing real problems, such as a decrease in the population in rural areas, a shortage of labor due to an aging population, and increased risks due to the deepening of climate change. Smart farming technology is being developed to solve these problems. In the development of smart agricultural technology, irrigation control plays an important role in creating an optimal growth environment and is an important issue in terms of environmental protection. This paper is about the study of collecting and analyzing the rhizosphere environmental data of domestic paprika farms for the purpose of improving the quality of crops, reducing production costs, and increasing production. Irrigation control modeling presented in this paper Control modeling is to graphically present changes in a medium weight, feed, and drainage due to regional climatic features. To derive the graph, the parameters were determined through data collection and analysis, and the suggested irrigation control modeling method was applied to the collected rhizosphere environmental data to control irrigation in 6 regions (Gangwon-do, Chungnam, Jeonbuk, Jeonnam, Gyeongbuk, and Gyeongnam). The parameters were obtained and graphs were derived from them. After that, a study was conducted to analyze the derived parameters to verify the validity of the irrigation control modeling method and to correlate them with climatic features (average temperature and precipitation).

• Journal of Intelligence and Information Systems
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• v.29 no.4
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• pp.347-373
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• 2023

As the significance of ESG (Environmental, Social, and Governance) management amplifies in driving sustainable growth, this study delves into and compares ESG trends and interrelationships from both corporate and societal viewpoints. Employing a combination of Latent Dirichlet Allocation Topic Modeling (LDA) and Semantic Network Analysis, we analyzed sustainability reports alongside corresponding social media datasets. Additionally, an in-depth examination of social media content was conducted using Joint Sentiment Topic Modeling (JST), further enriched by Semantic Network Analysis (SNA). Complementing text mining analysis with the assistance of ChatGPT, this study identified 25 different ESG topics. It highlighted differences between companies aiming to avoid risks and build trust, and the general public's diverse concerns like investment options and working conditions. Key terms like 'greenwashing,' 'serious accidents,' and 'boycotts' show that many people doubt how companies handle ESG issues. The findings from this study set the foundation for a plan that serves key ESG groups, including businesses, government agencies, customers, and investors. This study also provide to guide the creation of more trustworthy and effective ESG strategies, helping to direct the discussion on ESG effectiveness.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.55 no.4
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• pp.284-291
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• 2010

A simulation modeling for predicting the harvesting date with high potato solids consists of development of mathematical models. The mathematical model on potato growth and its development should be obtained by using agricultural elements which analyze relations of solar radiation quantity, temperature, photon quantity, carbon dioxide exchange rate, water stress and loss, relative humidity, light intensity, and wind etc. But more reliable way to predict harvesting date against climatic change employs in vivo energy consumption for growth and induction shape in a slight environmental adaptation. Therefore, to calculate in vivo energy loss, we take a concept of estimate of the amount of basal metabolism in each tuber on the basis of $Wm={\int}^m_tf(x)dt$ and $Tp=\frac{Tm{\cdot}Wm^{Tp}}{Wm^{Tm}}$. In the validation experiments, results of measuring solid accumulation of potato harvested at simulated date agreed fairly well with the actual measured values in each regional field during the growth period of 2005-2009. The calculation method could be used to predict an appropriate harvesting date for a production of high potato solids according to weather conditions.

• Journal of the Korea Convergence Society
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• v.13 no.4
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• pp.383-396
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• 2022

The purpose of this study was to investigate the effect of worker's innovative organizational culture on organizational commitment in companies. The research data were used from the fourth year (2011) to the seventh year (2017) of the HCCP (Human Capital Corporate Panel), and 207 companies were subject to the final analysis except for missing values. To statistically validate the research model, we utilize the SPSS 26.0 and AMOS 21.0 programs to perform Latent Growth Modeling analysis. The results of the study are as follows. First, both the innovative organizational culture and organizational commitment of companies have been shown to continue to decline over time. Second, the initial value of innovative organizational culture has been shown to have a significant impact on the initial value of organizational commitment. On the other hand, the initial value of innovative organizational culture has no significant effect on the rate of change in organizational commitment. Third, the rate of change in innovative organizational culture has been shown to have a significant impact on the rate of change in organizational commitment. Based on these findings, we present practical measures to enhance the importance of innovative organizational culture along with its implications.