• Journal of Wetlands Research
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• v.26 no.3
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• pp.245-253
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• 2024

Blue-green algal bloom, or harmful algal bloom has a negative impact on the aquatic ecosystem and purified water supply system due to oxygen depletion in the water body, odor, and secretion of toxic substances in the freshwater ecosystem. This Blue-green algal bloom is expected to increase in intensity and frequency due to the increase in algae's residence time in the water body after the construction of the Nakdong River weir, as well as the increase in surface temperature due to climate change. In this study, in order to respond to the expected increase in green algae phenomenon, an algal bloom forecast system based on hydro-meteorological factors was presented for preemptive response before issuing a algal bloom warning. Through polyserial correlation analysis, the preceding influence periods of temperature and discharge according to the algal bloom forecast level were derived. Using the decision tree classification, a machine learning technique, Classification models for the algal bloom forecast levels based on temperature and discharge of the preceding period were derived. And a algal bloom forecast system based on hydro-meteorological factors was derived based on the results of the decision tree classification models. The proposed algae forecast system based on hydro-meteorological factors can be used as basic research for preemptive response before blue-green algal blooms.

• Journal of The Korean Association For Science Education
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• v.44 no.4
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• pp.301-311
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• 2024

We developed a small-group training program for in-service teachers focused on scientific modeling. We collected the discourses of the teachers who participated in the activity and analyzed them by type. The training program employed a collaborative approach in which a small group completed tasks and produced outputs based on the theme of 'galaxies and the Universe' to enable practical application in classes. Three in-service science teachers participated in the training program. Their discourses were recorded, transcribed, and classified into types based on individual turns and interaction units. The language expressions of the teachers reflected the unique characteristics of the teaching profession, with each participant having preferred language expression types, albeit with a generally low prevalence of specific language expression types across the participants. Differences in discourse characteristics related to the modeling theme, task presentation method, and model types, revealed that variations in the proportion of interaction unit types during the modeling design, build, and evaluation stages were primarily influenced by the teachers' familiarity with the modeling theme. While the task presentation method also influenced interaction types, model types had little impact on the distribution of interaction types. Considering these findings, training programs on modeling for in-service teachers should include a checklist to encourage sufficient interaction between participants as well as propose proper questions that can be effectively addressed through collaboration.

• Journal of Practical Engineering Education
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• v.16 no.4
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• pp.599-609
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• 2024

The government has introduced the Regional Innovation System (RIS) to establish regional innovation platforms, leading to the creation of the Bio-PRIDE shared university in the Chungbuk region, centered around the bio-health industry. The purpose of this study is to analyze the educational service quality of the Bio-PRIDE shared university through a qualitative approach. To achieve this, in-depth exploration of the experiences of students participating in the Bio-PRIDE shared university was conducted using Focus Group Interviews (FGI) and telephone interviews. The study identified three main findings: 1) Motivations for student participation included recommendations and support from professors, economic benefits and scholarships, the flexibility and convenience of remote learning, and the appeal of new learning experiences and challenges. 2) Experiences during participation revealed themes such as the effectiveness and challenges of remote classes, the value of providing up-to-date technology and content, student engagement and commitment, and communication and support from faculty. 3) The impact of participation after completing the program highlighted the importance of innovative learning experiences and expanded choices, the significance of information accessibility and learning support, the need for improved promotion and awareness of the shared university, and the necessity for administrative support and communication. In conclusion, the Bio-PRIDE shared university has successfully implemented educational innovation, offering students new learning experiences and contributing to the broadening of their academic perspectives. This study will serve as a foundational resource for improving the educational service quality and ensuring the successful operation of the Bio-PRIDE shared university in the future.

• Journal of Practical Engineering Education
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• v.16 no.4
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• pp.541-551
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• 2024

Individual career development is getting more important in modern society. In this study, we investigated the effects of task difficulty and perceived colleague support to work grit and career identity, which are the most fundamental aspects of career development. To achieve the research goal, a total of 544 complete responses from the employees in South Korea were used for data analysis. The data was analyzed using structural equation modeling. The research results are as follows. First, task difficulty positively affect work grit. Second, perceived colleague support was found to have a statistically significant effect on work grit. Third, the path from task difficulty to career identity was not statistically significant. Fourth, perceived colleague support was shown to have a statistically significant effect on career identity. Fifth, work grit was found to have a statistically significant effect on career identity. Sixth, work grit was found to mediate the relationship between task difficulty, perceived colleague support, and career identity. These findings suggest that work grit plays a crucial mediating role in the impact of task difficulty and perceived colleague support on career identity. This underscores the need for continued in-depth exploration of work grit. Based on these research results, discussions and suggestions are presented.

• Journal of Nutrition and Health
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• v.57 no.4
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• pp.403-417
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• 2024

Purpose: This study investigated the anti-inflammatory effects of Evodiae Fructus (EF) on hydrochloric acid (HCl)/ethanol-induced gastritis, focusing on its impact on oxidative stress by analyzing inflammatory cytokines and inflammation-related factors. The total polyphenol and flavonoid contents were determined through in vitro experiments, while the radical scavenging activity was confirmed using 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) assays. Methods: In vivo experiments were conducted on rats divided into 5 groups (n = 7/in each group): normal group (Normal), 150 mM HCl/60% ethanol-induced gastritis group (Control), 150 mM HCl/60% ethanol-induced gastritis group administered 10 mg/kg sucralfate (SC), 150 mM HCl/60% ethanol-induced gastritis group administered EF at the doses of 100 mg/kg or 200 mg/kg (EF100 or EF200). The mice were pretreated with the extract (EF) or drug (SC), and after 1 hour, 150 mM HCl/60% ethanol (v/v) mixture was administered orally. Reactive oxygen species (ROS) levels, peroxynitrite (ONOO^-), and pro-inflammatory cytokines including tumor necrosis factor-α and interleukin-1 beta were assessed in serum. Additionally, western blotting of the gastric tissues confirmed the expression of inflammation-related proteins. Results: EF alleviated the gastric mucosal damage caused by 150 mM HCl/60% ethanol. The assessment of oxidative stress in the serum showed that EF significantly reduced ROS and ONOO^- levels and significantly decreased the levels of pro-inflammatory cytokines. Western blot analysis revealed that EF reduced ROS-generating nicotinamide adenine dinucleotide phosphate oxidase subunits, including gp91^phox, p22^phox, and p47^phox. Additionally, EF mitigated the inflammation by inhibiting the mitogen-activated protein kinase signaling pathway. Conclusion: These results indicate that EF is a potential herbal medicine candidate for the treatment of oxidative stress-induced gastritis.

• Journal of Navigation and Port Research
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• v.48 no.4
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• pp.321-326
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• 2024

The purpose of this study is to investigate whether Big 4 accounting firms contribute to the reduction of earnings management when auditing shipping companies. Generally, it is understood that companies audited by the Big 4 accounting firms engage in minimal earnings management and maintain high audit quality. However, these factors may vary depending on industry and firm size. As a result, this study empirically analyzes the impact of audits conducted by large accounting firms on earnings management within the shipping industry. The Big 4 accounting firms, namely PwC, KPMG, Deloitte, and EY, are the focus of this research. Discretionary accruals are employed as a proxy for earnings management, with the modified J ones model and the performance matched model used to measure discretionary accruals. The analysis, which covers shipping companies listed on KOSP I from 2001 to 2023, reveals that audits conducted by the Big 4 accounting firms do not significantly influence earnings management in the shipping industry. Unlike the general case, it is evident that audits by the Big 4 accounting firms do not play a role in reducing earnings management in shipping companies. This paper is significant as it examines the role of auditors within the shipping industry and presents findings that deviate from commonly known information. Shipping companies should take into consideration that the audit quality of the Big 4 accounting firms may not always be guaranteed when selecting an auditor. Furthermore, supervisory authorities such as the Financial Supervisory Service should engage in oversight based on an accurate understanding of the audit quality offered by the Big 4 accounting firms.

• The Korean Journal of Applied Statistics
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• v.37 no.4
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• pp.395-410
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• 2024

Text data is usually made up of a wide variety of unique words. Even in standard text data, it is common to find tens of thousands of different words. In text data analysis, usually, each unique word is treated as a variable. Thus, text data can be regarded as a dataset with a large number of variables. On the other hand, in text data classification, we often encounter class label imbalance problems. In the cases of substantial imbalances, the performance of conventional classification models can be severely degraded. To improve the classification performance of support vector machines (SVM) for imbalanced data, algorithms such as the Synthetic Minority Over-sampling Technique (SMOTE) can be used. The SMOTE algorithm synthetically generates new observations for the minority class based on the k-Nearest Neighbors (kNN) algorithm. However, in datasets with a large number of variables, such as text data, errors may accumulate. This can potentially impact the performance of the kNN algorithm. In this study, we propose a method for enhancing prediction performance for the minority class of imbalanced text data. Our approach involves employing variable selection to generate new synthetic observations in a reduced space, thereby improving the overall classification performance of SVM.

• Advances in concrete construction
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• v.17 no.2
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• pp.111-126
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• 2024

During the clinkering stages of cement production, the chemical composition of fine raw materials such as limestone and clay, which include iron oxide (Fe₂O₃), silicon dioxide (SiO₂) and aluminum oxide (Al₂O₃), significantly influences the quality of the final product. Specifically, the chemical interaction of Fe₂O₃ with CaO, SiO₂ and Al₂O₃ during clinkerisation plays a key role in determining the chemical reactivity and overall quality of the final cement, shaping the properties of the concrete produced. As an extension, this study aims to investigate the physical effects of incorporating nanosized Fe₂O₃ particles as fillers in concrete matrices, and their impact on concrete structures, namely slabs. To accurately model the reinforced concrete (RC) slabs, a refined trigonometric shear deformation theory (RTSDT) is used. Additionally, the stochastic Eshelby's homogenization approach is employed to determine the thermoelastic properties of nano-Fe₂O₃ infused concrete slabs. To ensure comprehensive coverage in the study, the RC slabs undergo various mechanical loads and are exposed to temperature fields to assess their thermo-mechanical performance. Furthermore, the slabs are assumed to rest on a three-parameter viscoelastic foundation, comprising the Winkler elastic springs, Pasternak shear layer and a damping parameter. The equilibrium governing equations of the system are derived using the principle of virtual work and subsequently solved using Navier's technique. The findings indicate that while ferric oxide nanoparticles enhance the mechanical properties of concrete against mechanical loading, they have less favorable effects on its performance against thermal exposure. However, the viscoelastic foundation contributes to mitigating these effects, improving the concrete's overall performance in both scenarios. These results highlight the trade-offs between mechanical and thermal performance when using Fe₂O₃ nanoparticles in concrete and underscore the importance of optimizing nanoparticle content and loading conditions to improve the structural performance of concrete structures.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.4
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• pp.13-27
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• 2024

The purpose of this study is to analyze whether startup CEOs' self-efficacy and hope have a mediating effect on the relationship between satisfaction with an acceleration program and business performance. While the impact of acceleration programs on business performance has been validated through various studies, this research aims to examine whether differences in business performance, despite participating in the same program, are attributable to the characteristics of the participants. To this end, satisfaction with the acceleration program was set as the independent variable, business performance (financial performance and non-financial performance) as the dependent variable, and self-efficacy and hope among positive psychological capital as the mediating variables. A survey was conducted on startup CEOs who participated in acceleration programs offered by financial public institutions, specifically the Korea Credit Guarantee Fund and the Industrial Bank of Korea, in order to minimize the influence of differences in accelerator competence and program quality. The empirical analysis results indicate that satisfaction with the acceleration program has a positive effect on both the financial and non-financial performance of startups, and hope serves as a mediating factor in this relationship. This study suggests that to improve business performance of startups, policy efforts are needed to activate and enhance the roles of domestic accelerators. Additionally, it proposes that in order to maximize the effectiveness of acceleration programs, detailed components of these programs should be designed to elevate the participants' level of hope.

• Journal of the Korea Society of Computer and Information
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• v.29 no.9
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• pp.99-107
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• 2024

This study analyzed how computer-based digital technology affects convergence performing arts according to the trend of the times of domestic performing arts. Based on the analyzed contents, the purpose of the study was to propose an appropriate use plan for performing arts and technology and a plan for future development of convergence performing arts. Looking at the analysis results according to the purpose of the study, as a first step, the use of video technology developed in the performing arts stage using video technology evolved into holograms, media art, and 3D techniques. In the second step, technology and art were fused using artificial intelligence and robots. Artificial intelligence composed music, choreographed dance, and wrote a play script. In addition, robots performed and played with humans on stage. Third, virtual space was also used in performing arts. It was possible to direct spaces in various places using virtual spaces rather than performance halls and stage spaces. In this way, performing arts using digital technology will become more diverse and professional, and things that are possible in imagination that cross boundaries will be developed into reality. This study proposes a convergence that appropriately utilizes various technologies of digital and computer while maintaining the area of creation that humans can do and the expressiveness and artistry they express. In preparation for these changes in the times, future convergence performing artists should be able to acquire a combination of artistry and technology of stage technology experts who can use digital technology, professional actors who can express artistry along with AI, and professionals who can create art by manipulating AI.