• Journal of Food Hygiene and Safety
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• v.39 no.5
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• pp.404-411
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• 2024

Paralytic Shellfish Poisoning (PSP) occurs when humans consume shellfish contaminated with saxitoxin (STX) and its derivatives. It causes symptoms ranging from numbness and nausea to severe muscle paralysis and respiratory failure. Toxic equivalency factors (TEFs) are used to standardize the toxic effects of various PSP toxins for risk assessment. Traditional detection methods, such as mouse bioassays, have been used to set the TEFs, but ethical concerns over in vivo studies have shifted the focus toward analytical methods, such as high-performance liquid chromatography. However, in vivo data are essential for establishing TEFs, particularly for emerging marine biotoxins. This study employed a three-level response surface pathway (RSP) design, which reduced the number of animals used to evaluate the median lethal dose (LD₅₀) of STX and its derivatives. The LD₅₀ and TEF values for STX dihydrochloride, neosaxitoxin, decarbamoylsaxitoxin, gonyautoxins 1 & 4 (GTX1&4), GTX2&3, and dcGTX2&3 were 451.3 (1.00), 306.5 (1.47), 860.9 (0.52), 644.5 (0.70), 915.3 (0.49), and 2409.3 (0.19) ㎍/kg, respectively. These TEFs closely aligned with the WHO recommendations and prior oral LD₅₀ values, with Pearson correlation coefficients of 0.969 and 0.994, respectively. This study highlights the need for accurate TEF assignments for PSP toxins and new marine biotoxins, demonstrating that the three-level RSP design balances ethical concerns and provides reliable toxicity data.

• Journal of Internet Computing and Services
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• v.25 no.5
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• pp.121-130
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• 2024

Tabular Data is a mixture of numerical and categorical data, and machine learning models have been evaluated to be more suitable than generative models in performing learning using such tabular data. This evaluation is because the generative model had a problem of excessively increasing parameters or not finding the direction of learning due to the numerical multimodal distribution and categorical frequency imbalance, which are characteristics of Tabular Data. However, as data gradually becomes big data and becomes real-time, existing machine learning models have shown limitations in their application. In this paper, as a methodology for applying generative models to tabular data, we propose RGGAN (Reinforced Generator GAN), a reinforced generator adversarial neural network that Clustering sampling that leverages conjugate prior distributions and the loss function improved with Gower coefficients and mutual information. As a result of measuring the AUC by detecting fraudulent transactions in the IEEE-CIS Fraud Detection Dataset by constructing an anomaly detector with the discriminators learned from the RGGAN proposed in this paper, it showed a performance improvement effect of 1-7% over the existing generative models, proving that the proposed model is effective for learning tabular data and also effective in detecting fraudulent transactions.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.19 no.5
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• pp.85-98
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• 2024

Since special listed companies are listed under relaxed conditions in management performance and market evaluation, if they do not continue to grow after listing, the damage to investors will inevitably increase. In addition, since special listed companies have a smaller company size than general listed companies, CEOs are inevitably more important in establishing corporate strategies. Therefore, this study empirically analyzed the characteristics of CEOs that affect R&D investment and corporate value of special listed companies from the perspective of behavioral finance theory. As a result of verifying the characteristics of CEOs who influence R&D investment through interactions with specially listed companies, it has a positive effect on R&D if the CEO is male, a natural science major, or a former investment company. In addition, the characteristics of CEOs who influence corporate value through interactions with variables of specially listed companies positively affected R&D if the CEO is male and has an academic background. The characteristics of CEOs who influence R&D investment and corporate value through interactions with specially listed companies are different from those of single variables in gender, education, major, and career variables excluding age, indicating that specially listed companies play a role as a control variable that affects R&D investment and corporate value through interaction with CEO characteristics. This study supplemented the limitations of the existing CEO theory and verified that age, gender, education, major, and career, which are CEO characteristics from a behavioral finance perspective, can be explanatory variables that reflect psychological differences in individual abilities. In addition, it is expected to contribute to research on corporate sustainability by providing implications for predicting the characteristics of CEOs who have high influence on R&D investment and corporate value of specially listed companies.

• Journal of the Korean Geotechnical Society
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• v.40 no.4
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• pp.61-68
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• 2024

Monitoring the injection degree of biopolymers in soils is required in estimating the performance of biopolymer-treated grounds. In this study, the degree of saturation and injection process of biopolymer solutions in sandy soils were evaluated using electrical resistivity. To assess the changes in electrical resistivity according to the contents of the biopolymer solutions, electrical resistivities were measured for Jumunjin sand-xanthan gum biopolymer solution (weight concentration of 0.5%) mixtures with different degrees of saturation of 20%, 40%, 60%, 80%, and 100%. In addition, electrical resistivities were measured at eight layers in oven-dried Jumunjin sand during the upward injection of the xanthan gum biopolymer solution to monitor the injection process. Experimental results showed that the electrical resistivity decreased as the degree of saturation of the mixture increased, and their relationship was constructed. During the injection of the xanthan gum biopolymer solution into the sandy soils, the electrical resistivity decreased and converged and the degree of saturation at each layer could be estimated on the basis of the above-constructed relationship. This study demonstrated that electrical resistivity may be an effective physical property for monitoring the injection degree of biopolymer solutions in the ground.

• Journal of Korean Society of Archives and Records Management
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• v.24 no.3
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• pp.23-44
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• 2024

In recent years, there has been a significant increase in the importance of curation services that analyze user information requests to provide tailored information within extensive information resources. This study aims to identify user information needs by analyzing search term logs from the Presidential Archives Portal to enhance the utilization value of presidential records, which possess high historical significance. In addition, by evaluating the portal's search performance, this study seeks to determine whether the Presidential Archives Portal is providing archival information services that meet users' information needs and to suggest areas for improvement through digital record curation services. To achieve these objectives, topic analysis and word network analysis were conducted based on search term logs spanning the past eight years. The search quality of the Presidential Archives Portal was evaluated from an accuracy perspective, focusing on areas with high user demand, and recommendations were drawn based on the results of the analysis. As a preliminary study for digital record curation of presidential records, this study is significant because it identifies specific user information needs and quantifies the search quality of archival portal sites to improve user satisfaction.

• Journal of the Institute of Convergence Signal Processing
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• v.25 no.2
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• pp.67-76
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• 2024

Various types of assistive devices have been developed for upper limb amputees over the years, with myoelectric prosthesis particularly aimed at improving user convenience by enabling a range of hand gestures beyond simple grasping, tailored to the size and shape of objects. In this study, we developed a five-finger myoelectric prosthesis mimicking human hand size and finger movements, utilizing motor and worm gear mechanisms for stable and independent operation. Based on this, we designed a control system for independent finger control through electromyographic signal input, proposed a state transition-based hand gesture conversion algorithm by selecting representative eight hand gestures and defining conversion condition parameters. We introduced training and usability evaluation methods, and conducted usability assessments among upper limb amputees using dedicated tools, confirming the potential for commercial application of the algorithm and observing adaptive capabilities and high performance through iterative evaluations.

• Tunnel and Underground Space
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• v.34 no.5
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• pp.571-598
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• 2024

Nuclear power generation, which belongs to the eco-friendly energy category, has a comparative advantage over other power generation methods in terms of cost and efficiency, and its share of electricity energy has recently shifted to an increasing trend worldwide. In Korea, various empirical studies have been conducted centering on KURT (KEARI Underground Research Tunnel) to secure elemental technology necessary for safe and efficient disposal of high-level radioactive waste inevitably generated during the operation of nuclear power plants. Considering the domestic rock type and geological conditions, the multi-barrier system is evaluated as the most effective among various high-level radioactive waste disposal methods. The objectives of this study were, first, to evaluate the hydraulic characteristics of deep and low-permeable rock masses and second, to secure quantitative information on the hydraulic connectivity between boreholes for establishing a large-scale in-situ test system necessary for the proper design and stability evaluation of the multi-barrier system. In this regard, diverse borehole tests using DHTS (Deep borehole Hydraulic Testing System) were performed in the two research modules in KURT, and in particular, the injection type cross-hole hydraulic connectivity tests were successfully completed for the first time in Korea. In this paper, we briefly introduced MDST (Mini Downhole Shut-in Tool) developed to update the performance of DHTS and mainly discussed the key results obtained from the stepwise in-situ borehole tests.

• Applied Chemistry for Engineering
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• v.35 no.3
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• pp.200-208
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• 2024

Chung's equations-IX and Chung's equation-XII were utilized to predict the fire risk and evaluate fire risk ratings for four types of wood: camphor, cherry, rubber, and elm trees. The combustion tests were conducted using a cone calorimeter test method by ISO 5660-1 standards. The fire risk and fire risk rating (FRR) were compared for Fire Risk Index-IX (FRI-IX) and Fire Risk Index-XII (FRI-XII). The results yielded Fire Performance Index-XI (FPI-XI) ranging from 0.08 to 11.48 and Fire Growth Index-XI (FGI-XI) ranging from 0.67 to 111.89. The Fire Risk Index-XII (FRI-XII), indicating fire risk rating, exhibited an increasing order of cherry (0.45): Grade A (Ranking 5) < PMMA (1): Grade A (Ranking 4) < elm (1.23): Grade A (Ranking 3) < rubber (1.56): Grade A (Ranking 2) << camphor (148.23): Grade G (Ranking 1). Additionally, the fire risk index-IX (FRI-IX) was cherry (0): Grade A (Ranking 3) ≈ rubber (0): Grade A (Ranking 3) ≈ elm tree (0): Grade A (Ranking 3) < PMMA (1): Grade A (Ranking 2) << camphor tree (66.67): Grade G (Ranking 1). In general, camphor was found to have the highest fire risk. In conclusion, although the expression of the index is different as shown based on the standards of FRI-IX and FRI-XII, predictions based on fire risk assessment of combustible materials showed similar trends.

• Journal of Korea Port Economic Association
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• v.40 no.1
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• pp.87-118
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• 2024

Coastal ports play an essential role in developing a country and a city. Port efficiency is an important factor affecting port trade, and the importance of port efficiency for port performance has been recognized in previous literature. DEA (Data Envelopment Analysis) and SFA (Stochastic Frontier Analysis) are widely used in this field of research. However, these two methods are limited in selecting input and output variables. In addition, the literature studies on Chinese coastal ports mainly focus on the study of port clusters in local areas, which lacks a holistic approach and generally lacks up-to-date data. Therefore, to fill the gap in this area of research, this paper introduces a model combining principal component analysis and data envelopment analysis to analyze the operational efficiency of the top 17 coastal ports in China in terms of throughput based on the most recent data available in 2021. This paper identifies container throughput as the output variable, and 13 second indicators are selected as input variables from four primary indicators: land, capital, labor, and infrastructure. Four principal components were selected from 13 second indicators using PCA.After that, DEA (BBC) and DEA (CCR) were used to analyze the 17 ports, among which five were Shanghai, Ningbo-Zhoushan, Guangzhou, Xiamen, and Dongguan, respectively, DEA efficient, and the remaining 12 ports were non-DEA efficient. Finally, improvement directions for each port are derived, and brief suggestions are made. This paper provides some reference value for developing and constructing coastal ports in China.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.645-661
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• 2024

Today, the development of new technologies due to the 4th industrial revolution requires work performance methods such as non-face-to-face collaboration. In response to this, various VR collaboration tools are emerging, but VR collaboration tools for brainstorming, which are used in collaboration or design development work, are not provided. Therefore, despite the advantages and possibilities of VR for non-face-to-face collaboration, there are limitations in practical use. Accordingly, the development of VR collaboration tools in a digitalized work environment is necessary, and research on UI design development for this is required. The purpose of this study is to propose a VR collaboration tool prototype by developing an interaction UI design that applies user hand behavior elements that appear during collaboration sessions through user research. This study was a qualitative study. The research method was to conduct user research through observation and in-depth interviews, and as a result of analyzing the data obtained from this, five types of user hand behavior elements were derived. In this study, an interaction UI design was developed that reflects hand gestures as behavioral elements. And using Unity and the Oculus Integration SDK Kit, we created a prototype VR collaboration tool that can be used without a controller. As a result of conducting a user evaluation of the prototype produced in this study, it was found that users had difficulty making hand gestures accurately, and it was possible to find areas for improvement in UI design. It is expected that this study will help develop interaction UI design for VR collaboration tools that can increase work efficiency.