• Journal of Information Technology Applications and Management
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• v.30 no.6
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• pp.31-52
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• 2023

The government's various support policies have helped Korea's SMEs and startups to grow from the beginning to the end, from domestic companies to exporters. In particular, direct business support policies such as financial support, R&D projects, and export support have been effective in helping a large number of entrepreneurs and startup companies to establish themselves in the market and have achieved tangible results every year since the establishment of the Ministry of SMEs and Startups. As such, the government is making significant efforts to create and promote various types of support policies and to help companies utilize them in their business. However, this study aims to analyze the factors that affect the satisfaction of government policies and the achievement of managerial performance from the companies' perspective and to suggest the purpose of government support policies and the direction companies should take. Specifically, this study categorizes entrepreneurial self-efficacy into marketing, innovation, management, risk-taking, and financial management, using the relationship model of self-efficacy and collective efficacy to ultimately lead to practical results for SMEs and startups support policies. It uses perceived firm efficacy as a variable to reveal the influence relationship. In addition, the direct and mediating effects of entrepreneurial self-efficacy and policy satisfaction on managerial performance were analyzed to determine what SMEs and startups support policies should do. The results showed that, first, among the five components of entrepreneurial self-efficacy, innovation, and risk-taking efficacy positively affected perceived firm efficacy. Second, the specific components of entrepreneurial self-efficacy, marketing, and financial management efficacy positively influenced policy satisfaction. Third, we found that perceived firm efficacy positively influenced policy satisfaction and managerial performance, which are factors of SMEs and startups' policy performance. Specifically, perceived firm efficacy positively influenced policy satisfaction managerial performance. Fourth, we found that policy satisfaction positively influenced managerial performance.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.17 no.11
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• pp.3182-3203
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• 2023

With the growing adoption of cloud-based technologies, maintaining the privacy and security of cloud data has become a pressing issue. Privacy-preserving encryption schemes are a promising approach for achieving cloud data security, but they require careful design and implementation to be effective. The integrated approach to cloud data security that we suggest in this work uses CogniGate: the orchestrated permissions protocol, index trees, blockchain key management, and unique Opacus encryption. Opacus encryption is a novel homomorphic encryption scheme that enables computation on encrypted data, making it a powerful tool for cloud data security. CogniGate Protocol enables more flexibility and control over access to cloud data by allowing for fine-grained limitations on access depending on user parameters. Index trees provide an efficient data structure for storing and retrieving encrypted data, while blockchain key management ensures the secure and decentralized storage of encryption keys. Performance evaluation focuses on key aspects, including computation cost for the data owner, computation cost for data sharers, the average time cost of index construction, query consumption for data providers, and time cost in key generation. The results highlight that the integrated approach safeguards cloud data while preserving privacy, maintaining usability, and demonstrating high performance. In addition, we explore the role of differential privacy in our integrated approach, showing how it can be used to further enhance privacy protection without compromising performance. We also discuss the key management challenges associated with our approach and propose a novel blockchain-based key management system that leverages smart contracts and consensus mechanisms to ensure the secure and decentralized storage of encryption keys.

• Journal of the Korea Society of Computer and Information
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• v.29 no.6
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• pp.113-120
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• 2024

With the advancement of information and communication technology, we can easily generate various forms of data in our daily lives. To efficiently manage such a large amount of data, systematic classification into categories is essential. For effective search and navigation, data is organized into a tree-like hierarchical structure known as a category tree, which is commonly seen in news websites and Wikipedia. As a result, various techniques have been proposed to classify large volumes of documents into the terminal nodes of category trees. However, document classification methods using category trees face a problem: as the height of the tree increases, the number of terminal nodes multiplies exponentially, which increases the probability of misclassification and ultimately leads to a reduction in classification accuracy. Therefore, in this paper, we propose a new node expansion-based classification algorithm that satisfies the classification accuracy required by the application, while enabling detailed categorization. The proposed method uses a greedy approach to prioritize the expansion of nodes with high classification accuracy, thereby maximizing the overall classification accuracy of the category tree. Experimental results on real data show that the proposed technique provides improved performance over naive methods.

• Mass Spectrometry Letters
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• v.15 no.1
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• pp.40-48
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• 2024

Capacity of the analytical/quantitative evaluation techniques to satisfy both qualitative and quantitative considerations for effective extraction of marigold oleoresins/xanthophylls and their potential as anti-mycotic and antioxidant activity was assessed. Accelerated solvent extraction (ASE), Soxhlet extraction (SE), Supercritical fluid extraction (SCFE), Cold extraction (CE), and ultrasonically assisted extraction (USE) techniques were evaluated for extraction of oleoresin/xanthophyll content from Tagetes erecta (Var. Pusa Narangi Genda) with respect to solvent consumption, extraction time, reproducibility, and yield. Followed by the antifungal and antioxidant activity evaluation. The overall yield of Tagetes oleoresin was higher in ASE (64.5 g/kg) followed by SE (57.3 g/kg), USE (50.7 g/kg), SCFE (45.3 g/kg) and CE (31.6 g/kg). The lutein esters represented more than 80% of the constituents. Further, xanthophyll/ lutein content in oleoresin was found to be quite higher in HPLC (r2 = 0.996) analysis than in the AOAC recommended UV spectrophotometer analysis. The oleoresin exhibited moderate antioxidant activity (DPPH assay) and antifungal activity against three phytopathogenic fungi. Based on the various parameters, the reproducibility of ASE was better (0.3-8.0%) than that of SE (0.5-12.9%), SCFE (0.2-9.4%), USE (0.3-12.4%) and CE (0.8-15.3%). ASE with (RSD 1.6%) is preferred being faster, reproducible, uses less solvent, robust and automation allows sequential extraction of the sample in less time.

• Journal of Korea Society of Industrial Information Systems
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• v.29 no.3
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• pp.23-40
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• 2024

Hardware attacks involve physical reverse engineering efforts to steal sensitive information, such as encryption keys and circuit designs. Encryption and obfuscation are representative countermeasures, but they are nullified if adversaries manage to find the key. To address this issue, we propose e-Cryptex, which utilizes a Physically Unclonable Function (PUF) as an anti-tampering shield. PUF acts as a random number generator and relies on unique physical variants that cannot be replicated or restored to enhance anti-tampering mechanisms. e-Cryptex uses PUF as a shield to protect the system's structure and generate the key. Tampering with the shield will result in the destruction of the key. This paper demonstrates that e-Cryptex meets PUF security requirements and is effective in detecting of tampering attempts that pierce or completely destroy the shield. Each board consistently generates the same key under normal conditions, while also showing key uniqueness across different boards.

• Convergence Security Journal
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• v.23 no.5
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• pp.165-172
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• 2023

Nation-state social engineering attacks are steadily being carried out as they are highly effective attacks, primarily to gain an advantage over secret information, diplomatic negotiations or future policy changes. As The Ukraine-Russia war prolongs, the activities of global hacking organizations are steadily increasing, and large-scale cyberattack attempts against major infrastructure or global companies continue, so a countermeasure strategy is needed. To this end, we determined that the social engineering attack cycle excluding physical contact among various social engineering models is the most suitable model, and analyzed the preferred social engineering attack method by comparing it with geopolitical tactics through case analysis. AS a result China favors phishing attacks, which prefer quantity over quality, such as man-made tactics, Russia prefers covert and complex spear phishing reminiscent of espionage warfare, and North Korea uses geopolitical tactics such as spear phishing and watering holes for attacks on the US and South Korea Most of the other countries aimed to secure funds with ransomware. Accordingly, a Clean Pass policy for China, periodic compulsory education in Russia, and international sanctions against North Korea were presented as countermeasure strategies.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.3
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• pp.610-632
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• 2024

Mobile Learning (M-learning) adoption and success in supporting students' learning engagement mainly depend on many factors. Therefore, this study systematically reviews the literature, synthesizes and analyzes the predictors of M-learning adoption, and uses success for students' learning engagement. Literature from 2016 to 2023 in various databases is covered in this study. Based on the review's findings, the factors that influence students' learning engagement when it comes to M-learning usage and adoption, can be divided into technical, pedagogical, and social factors. More specifically, technical factors include mobile devices availability and quality, connectivity to the internet, and user-friendly interfaces, pedagogical factors include effective instructional design, teaching methods, and assessment strategies, and social factors include motivation of students, social interaction and perceived enjoyment - all these factors have a significant impact on the M-learning adoption and use success. The findings of the review also indicated that M-learning has a key role in enhancing the learning engagement of students through different ways, like increasing their motivation, attention, and participation in their process of learning, paving the way for interaction and building relationships opportunities with peers and instructors, which in turn, can lead to strengthening the learning environment. The implications of these findings extend beyond immediate educational contexts, offering vital insights for future educational technology strategies and policy decisions, particularly in addressing global educational challenges and embracing technological advancements in learning.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.18 no.4
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• pp.922-937
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• 2024

Maritime activities are on the rise, there is a growing demand for high-quality communication services that can cover larger areas. However, the transmission of high data rates to maritime users is challenging due to path loss from land base stations, which limits the transmission power. To overcome this challenge, researchers have been exploring the use of buoys in a marine environment as relays for communication technology. This paper proposes a simulation-based approach to investigate the impact of various beamwidths on communication performance when using a buoy as a relay. The objective is to determine the optimal beamwidth that yields the highest data rate for the target location. The approach is based on an offshore wave model where the direction of the buoy changes according to the height of the wave. The study investigates the performance of the relay in the downlink situation using receive beamforming, and the capacity at the user in the three-hop situation is verified using an amplify-and-forward (AF) relay that uses transmit beamforming to the user. The simulation results suggest that the beamwidth of the relay should be adjusted according to the wave conditions to optimize the data rate and relay position that satisfies a data rate superior to the direct path to the target position. Using a buoy as a relay can be a promising solution for enhancing maritime communications, and the simulation-based approach proposed in this paper can provide insights into how to optimize beamwidth for effective communication system design and implementation. In conclusion, the study results suggest that the use of buoys as relays for maritime communication is a feasible solution for expanding coverage and enhancing communication quality. The proposed simulation-based approach provides a useful tool for identifying relay beamwidths for achieving higher data rates in different wave conditions. These findings have significant implications for the design and deployment of communication systems in maritime environments.

• Nutrition Research and Practice
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• v.18 no.2
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• pp.239-256
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• 2024

BACKGROUND/OBJECTIVES: Over the past 10 yrs, the prevalence of diabetes in Korea has continued to incline, and the importance of lifestyle modification to manage diabetes has been highlighted. For patients with diabetes, carbohydrate intake reduction is effective in improving glycemic control; thus, we aimed to analyze the effect of carbohydrate intake ratio and suggest an appropriate carbohydrate intake ratio. SUBJECTS/METHODS: Using the 8th Korea National Health and Nutrition Examination Survey (2019-2021), we analyzed the data including participants aged 30 yrs or older with diabetes, and they were stratified into good and poor glycemic control groups. To analyze the correlation between the dietary behavior characteristics of participants with diabetes and the carbohydrate intake ratio, sociodemographic characteristics, dietary behavior, and health behavior were adjusted, and multivariate logistic regression analysis was conducted to present the adjusted odds ratio and 95% confidence interval (CI). RESULTS: In the unadjusted crude model, when carbohydrate intake ratio in total energy intake increased by 1%, the likelihood of poor glycemic control increased by 1.007-fold (95% CI, 0.998-1.016; P = 0.121). In model 1, which uses age and sex as adjustment variables, an increase of up to 1.011-fold was possible (95% CI, 1.001-1.021; P = 0.008). In model 2, which added variables such as diabetes duration, frequency of fruit consumption, frequency of lunch and, frequency of dinner, the risk of poor glycemic control increased by 1.010-fold as the carbohydrate intake ratio increased (95% CI, 0.998-1.022; P < 0.001). CONCLUSION: This study confirmed that as the ratio of carbohydrate intake to total energy intake increases the likelihood of poor glycemic control also increases in patients with diabetes. Therefore, to improve glycemic control in patients with diabetes, controlling the carbohydrate intake may be helpful.

• Journal of Integrative Natural Science
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• v.17 no.2
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• pp.33-41
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• 2024

Abnormal climate is a phenomenon in which meteorological factors such as temperature and precipitation are significantly higher or lower than normal, and is defined by the World Meteorological Organization as a 30-year period. However, over the past 30 years, abnormal climate phenomena have occurred more frequently around the world than in the past. In Korea, abnormal climate phenomena such as abnormally high temperatures on the Korean Peninsula, drought, heatwave and heavy rain in summer are occurring in March 2023. Among them, heatwaves are expected to increase in frequency compared to other abnormal climates. This suggests that heatwave should be recognised as a disaster rather than just another extreme weather event. According to several previous studies, greenhouse gases and meteorological factors are expected to affect heatwaves, so this paper uses logistic regression and discriminant analysis on meteorological element data and greenhouse gas data in Gwangju from 2008 to 2022. We analyzed the impact of heatwaves. As a result of the analysis, greenhouse gases were selected as effective variables for heatwaves compared to the past, and among them, chlorofluorocarbons were judged to have a stronger effect on heatwaves than other greenhouse gases. Since greenhouse gases have a significant impact on heatwaves, in order to overcome heatwaves and abnormal climates, greenhouse gases must be minimized to overcome heatwaves and abnormal climates.