• Industry Promotion Research
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• v.8 no.1
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• pp.103-110
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• 2023

This study targeted KakaoTalk app users, mainly in Seoul and the metropolitan area, and verified the factors that had a significant impact on the intention to continuously use the app through KakaoTalk contents. Among various content characteristics, five variables were used to verify the variables that had the greatest influence on the intention to continue using, and the ones that did not. As a result of testing the five hypotheses, it was found that convenience, enjoyment, informativeness, and perceived usefulness had a significant positive(+) effect on the intention to continue using, but intimacy did not. From this, it can be determined that the majority of users use the app content because it is useful and informative, rather than because they have a sense of familiarity. In this way, the purpose of this study is to provide empirical help to factors closely related to the intention of continuous use in deriving priorities to be considered in the service planning stage as well as in terms of technical design of contents when developing mobile apps in the mobile app industry as a whole and in the field in the future. I want to provide it, but there is a meaning.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.1B
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• pp.55-64
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• 2008

The evidence of changes in the climate system is obvious in the world. Nevertheless, at the current techniques for flood frequency analysis, the flood distribution can not reflect climate change or long-term climate cycles. Using a linear regression and a Mann-Kendall test, trends in annual maximum precipitation and flood data for several major gauging sites were evaluated. Moreover, this research considered incorporating flood trends by climate change effects in flood frequency analyses. For five rainfall gauging sites (Seoul, Incheon, Ulleungdo, Jeonju, and Gangneung), upward trends were observed in all gauged annual maximum precipitation records but they were not statistically significant. For three streamflow gauging sites (Andong Dam, Soyanggang Dam, and Daecheong Dam), upward trends were also observed in all gauged annual maximum flood records, but only the flood at Andong Dam was statistically significant. A log-normal trend model was introduced to reflect the observed linear trends in annual maximum flood series and applied to estimate flood frequency and risk for Andong Dam and Soyanggang Dam. As results, when the target year was 2005, 50-year floods of the log-normal trend model were 41% and 21% larger then those of a log-normal model for Andong Dam and Soyanggang Dam, respectively. Moreover, the estimated floods of the log-normal trend model increases as the target year increases.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1D
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• pp.115-123
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• 2006

Recently, construction claims have been increased for protecting the rights of construction participants and effectively adjusting the changes under the contract. Thus, the importance of claim management has been emphasized in the construction industry. In domestic construction industry, some claim issues involved in construction activities are often being developed into disputes and even litigations because of the absence of methods or systems for the dispute resolution, and the lack of judicial precedents which can be provided as the references for resolving a particular dispute. In general, the judicial precedents related to the disputes and litigations occurred among construction participants would be extremely valuable in evaluating and analyzing current claims issues. However, such useful information has not been effectively accumulated and utilized in resolving the similar or sometimes identical types of disputes, thus requiring a large amount of additional costs, time and efforts. The primary objective of this study is to propose a web-based decision support system for construction claim management, which enables contractual participants to easily access and use the information of the judicial precedents related to the current construction claims. The decision support system is composed of 'prevention' and 'settlement' modules for avoiding and systematically resolving the construction claims.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.6A
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• pp.625-639
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• 2009

Experimental and analytical studies are performed on the mechanical behavior of concrete-filled tubular(CFT) truss girders for different f/L ratios. Bending tests are conducted on two CFT truss girder specimens to determine fundamental structural characteristics such as the strength and deformation properties. Nonlinear material models for CFT members subjected to an axial compressive force are compared in this paper by using the nonlinear finite element program, ABAQUS. Previous researchers have proposed several nonlinear stress-strain models of confined concrete. In this study, the nonlinear analyses are performed applying several stress-strain models for confined concrete proposed by Mander, Sakino, Han, Susantha and Ellobody, and the results are compared with the experimental results in terms of load-deflection and load-strain relationships. Based on the comparisons of the load-deflection relationships, the models proposed by Mander and Susantha provide a maximum load about 12.0~13.8% higher and that by Sakino gives a maximum load about 7.6% higher than the experimental results. The models proposed by Han and Ellobody give a maximum load only about 0.2~1.2% higher than the test results, showing the best agreement among the proposed stress-strain models. However, the load-strain relations predicted by the existing models generally provide conservative results exhibiting larger strains than the experimental data.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.33 no.5
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• pp.827-846
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• 2023

Recently, various information technologies such as network communication and sensors have begun to be integrated into weapon systems that were previously operated in stand-alone. This helps the operators of the weapon system to make quick and accurate decisions, thereby allowing for effective operation of the weapon system. However, as the involvement of the cyber domain in weapon systems increases, it is expected that the potential for damage from cyber attacks will also increase. To develop a secure weapon system, it is necessary to implement built-in security, which helps considering security from the requirement stage of the software development process. The U.S. Department of Defense is implementing the Risk Management Framework Assessment and Authorization (RMF A&A) process, along with the introduction of the concept of cybersecurity, for the evaluation and acquisition of weapon systems. Similarly, South Korea is also continuously making efforts to implement the Korea Risk Management Framework (K-RMF). However, so far, there are no cases where K-RMF has been applied from the development stage, and most of the data and documents related to the U.S. RMF A&A are not disclosed for confidentiality reasons. In this study, we propose the method for inferring the composition of the K-RMF based on systematic threat analysis method and the publicly released documents and data related to RMF. Furthermore, we demonstrate the effectiveness of our inferring method by applying it to the naval battleship system.

• Journal of the Korean Association of Geographic Information Studies
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• v.26 no.4
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• pp.145-160
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• 2023

The purpose of this study was to compare and analyze diurnal thermal environments using Unmanned Aerial Vehicles(UAV)-derived physical parameters(NDVI, SVF) and ENVI-met modeling. The research findings revealed significant correlations, with a significance level of 1%, between UAV-derived NDVI, SVF, and thermal environment elements such as S↑, S↓, L↓, L↑, Land Surface Temperature(LST), and Tmrt. In particular, NDVI showed a strong negative correlation with S↑, reaching a minimum of -0.52^** at 12:00, and exhibited a positive correlation of 0.53^** or higher with L↓ at all times. A significant negative correlation of -0.61^** with LST was observed at 13:00, suggesting the high relevance of NDVI to long-wavelength radiation. Regarding SVF, the results showed a strong relationship with long-wave radiative flux, depending on the SVF range. These research findings offer an integrated approach to evaluating thermal comfort and microclimates in urban areas. Furthermore, they can be applied to understand the impact of urban design and landscape characteristics on pedestrian thermal comfort.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.17 no.3
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• pp.1-17
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• 2022

This study studied the effect of the TIPS support project of the Ministry of SMEs and Startups on the entrepreneurship of TIPS start-ups. The Tips start-up company, which is the subject of the study, was selected for the TIPS support project, participated in all commercialization funds, incubation facilities, and capacity building programs, and was selected as a company that received private investment. One-on-one in-depth interviews were conducted for about eight weeks from January 14, 2022 to March 11, 2022. For this study, the TIPS support project was subdivided into four categories: commercialization funds, incubation facilities, capacity building programs, and private investment attraction, and entrepreneurship factors were classified into four categories: innovation, challenge spirit, leadership, and risk-taking. As a result of the in-depth interview, the influence of the TIPS support project on entrepreneurship factors was in the order of challenge spirit, innovation, risk-taking, and leadership. Specifically, it was found that commercialization funds influenced innovation and risk-taking, incubation facilities had a challenge spirit and risk-taking, competency-building programs had a challenge spirit and leadership, and attracting private investment had an influence on innovation and challenge spirit. The implications of this study are that the TIPS support project, a private investment-led technology start-up support program, was introduced in 2013 and as of the end of March 2022, and a report was prepared focusing on visible performance such as private investment performance and employment rate. However, through this study, by analyzing whether the TIPS support project contributed to the cultivation of entrepreneurship for TIPS start-ups, it was found that it had a positive influence not only on quantitative growth but also on qualitative growth.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.6
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• pp.541-554
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• 2023

The utilization of underground spaces in relation to tunnels and energy/waste storage is on the rise. To ensure the stability of underground spaces, it is crucial to reinforce rock fractures and discontinuities. Discontinuities, such as joints, can weaken the strength of the rock and lead to groundwater inflow into underground spaces. In order to enhance the strength and stability of the area around these discontinuities, rock grouting techniques are employed. However, during rock grouting, it is impossible to visually confirm whether the grouting material is being smoothly injected as intended. Without proper injection, the expected increases in strength, durability, and degree of consolidation may not be achieved. Therefore, it is necessary to predict in advance whether the grouting material is being injected as designed. In this study, we aimed to assess the injection performance based on injection variables such as the water/cement mixture ratio, injection pressure, and injection flow using UDEC (Universal Distinct Element Code) numerical program. Additionally, numerical results were validated by the lab experiment. The results of this study are expected to help optimize variables such as injection material properties, injection time, and pump pressure in the grouting design in the field.

• Journal of the Korea Institute of Construction Safety
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• v.6 no.1
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• pp.7-11
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• 2024

Pump car is an equipment that transports concrete products as needed to the place where they are poured. In order to pour a large amount of concrete in a short period of time, using a pump car is the most efficient in terms of economic efficiency and quality control. However, recently, many casualties have occurred due to boom damage during concrete pouring, so this study suggests that improvements are needed in the equipment manufacturing stage, inspection standards for old equipment, and equipment rental system. The reason is that, as a result of the finite element analysis of the pump car, the significant stress acting at the second stage of the boom and the maximum stress at the top of the boom were found to be 895.39 MPa, and M.S. Since it was evaluated the lowest at 0.04, the need for reinforcement was recognized. And it was confirmed that the 2nd stage boom was the most stressful and vulnerable part of the 1st to 5th stage booms. Therefore, it is necessary to increase the thickness and rigidity of members at the design and manufacturing stage, and to reinforce the steel plates of currently used equipment. In addition, it is urgent to establish a system that makes non-destructive testing mandatory for all general construction machinery and holds inspection agencies responsible for missing boom defects during non-destructive testing and regular inspections.

• The Mathematical Education
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• v.63 no.2
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• pp.165-186
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• 2024

Despite the growing attention on artificial intelligence-based automated scoring technology as a support method for the introduction of descriptive items in school environments and large-scale assessments, there is a noticeable lack of foundational research in mathematics compared to other subjects. This study developed an automated scoring model for two descriptive items in first-year middle school mathematics using the Random Forest algorithm, evaluated its performance, and explored ways to enhance this performance. The accuracy of the final models for the two items was found to be between 0.95 to 1.00 and 0.73 to 0.89, respectively, which is relatively high compared to automated scoring models in other subjects. We discovered that the strategic selection of the number of evaluation categories, taking into account the amount of data, is crucial for the effective development and performance of automated scoring models. Additionally, text preprocessing by mathematics education experts proved effective in improving both the performance and interpretability of the automated scoring model. Selecting a vectorization method that matches the characteristics of the items and data was identified as one way to enhance model performance. Furthermore, we confirmed that oversampling is a useful method to supplement performance in situations where practical limitations hinder balanced data collection. To enhance educational utility, further research is needed on how to utilize feature importance derived from the Random Forest-based automated scoring model to generate useful information for teaching and learning, such as feedback. This study is significant as foundational research in the field of mathematics descriptive automatic scoring, and there is a need for various subsequent studies through close collaboration between AI experts and math education experts.