• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.439-455
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• 2020

Numerical model was developed that simulates radionuclide (3H and 14C) transport modeling at the 2nd phase facility at the Wolsong LILW Disposal Center. Four scenarios were simulated with different assumptions about the integrity of the components of the barrier system. For the design case, the multi-barrier system was shown to be effective in diverting infiltration water around the vaults containing radioactive waste. Nevertheless, the volatile radionuclide 14C migrates outside the containment system and through the unsaturated zone, driven by gas diffusion. 3H is largely contained within the vaults where it decays, with small amounts being flushed out in the liquid state. Various scenarios were examined in which the integrity of the cover barrier system or that of the concrete were compromised. In the absence of any engineered barriers, 3H is washed out to the water table within the first 20 years. The release of 14C by gas diffusion is suppressed if percolation fluxes through the facility are high after a cover failure. However, the high fluxes lead to advective transport of 14C dissolved in the liquid state. The concrete container is an effective barrier, with approximately the same effectiveness as the cover.

• Journal of Distribution Science
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• v.20 no.9
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• pp.29-38
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• 2022

Purpose: The purpose of this study to determine the effect of distribution transformational and transactional project manager leadership style on the extra-role performance of project team members using multi-level modelling analysis. Research design, data and methodology: The role of psychological factors as the mediating variable namely is self-efficacy in the effect of project manager's leadership style on the project team members' performance was also studied using the Monte Carlo bootstrapping method. The sample of the study consisting of 370 project team members from 74 contractors registered with the Construction Industry Development Board in the Klang Valley was selected using a simple random sampling and a survey using a questionnaire. Results: The findings showed that the transformational leadership of project managers was a dominant predictor of extra-role performance of project team members. Furthermore, the study show the self-efficacy of project team members acted as a mediator in the relationship between transformational and transactional leadership of project manager leadership on the extra-role performance of project team members. Conclusions: The findings are expected to be used by the relevant parties in planning, arranging and implementing efforts to improve the work performance and ensure that projects are implemented according to the specified specifications.

• Journal of Internet Computing and Services
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• v.24 no.4
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• pp.37-45
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• 2023

Adaptive has gained significant attention in Education Technology (EdTech), with personalized learning experiences becoming increasingly important. Next-generation chatbots, including models like ChatGPT, are emerging in the field of education. These advanced tools show great potential for delivering personalized and adaptive learning experiences. This paper reviews previous research on adaptive learning and the role of chatbots in education. Based on this, the paper explores current and future chatbot technologies to propose a framework for using ChatGPT or similar chatbots in adaptive learning. The framework includes personalized design, targeted resources and feedback, multi-turn dialogue models, reinforcement learning, and fine-tuning. The proposed framework also considers learning attributes such as age, gender, cognitive ability, prior knowledge, pacing, level of questions, interaction strategies, and learner control. However, the proposed framework has yet to be evaluated for its usability or effectiveness in practice, and the applicability of the framework may vary depending on the specific field of study. Through proposing this framework, we hope to encourage learners to more actively leverage current technologies, and likewise, inspire educators to integrate these technologies more proactively into their curricula. Future research should evaluate the proposed framework through actual implementation and explore how it can be adapted to different domains of study to provide a more comprehensive understanding of its potential applications in adaptive learning.

• Journal of Korean Association for Spatial Structures
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• v.23 no.3
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• pp.87-94
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• 2023

Chloride is one of the most common threats to reinforced concrete (RC) durability. Alkaline environment of concrete makes a passive layer on the surface of reinforcement bars that prevents the bar from corrosion. However, when the chloride concentration amount at the reinforcement bar reaches a certain level, deterioration of the passive protection layer occurs, causing corrosion and ultimately reducing the structure's safety and durability. Therefore, understanding the chloride diffusion and its prediction are important to evaluate the safety and durability of RC structure. In this study, the chloride diffusion coefficient is predicted by machine learning techniques. Various machine learning techniques such as multiple linear regression, decision tree, random forest, support vector machine, artificial neural networks, extreme gradient boosting annd k-nearest neighbor were used and accuracy of there models were compared. In order to evaluate the accuracy, root mean square error (RMSE), mean square error (MSE), mean absolute error (MAE) and coefficient of determination (R2) were used as prediction performance indices. The k-fold cross-validation procedure was used to estimate the performance of machine learning models when making predictions on data not used during training. Grid search was applied to hyperparameter optimization. It has been shown from numerical simulation that ensemble learning methods such as random forest and extreme gradient boosting successfully predicted the chloride diffusion coefficient and artificial neural networks also provided accurate result.

• Journal of the Earthquake Engineering Society of Korea
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• v.27 no.2
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• pp.91-99
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• 2023

Structural vibration induced by earthquake hazards is one of the most significant concerns in structure performance-based design. Structural hazards evoked from seismic events must be properly identified to make buildings resilient enough to withstand extreme earthquake loadings. To investigate the effects of combined earthquake-resistant systems, shear walls and five types of dampers are incorporated in nineteen structural models by altering their arrangements. All the building models were developed as per ACI 318-14 and ASCE 7-16. Seismic fragility curves were developed from the incremental dynamic analyses (IDA) performed by using seven sets of ground motions, and eventually, by following FEMA P695 provisions, the collapse margin ratio (CMR) was computed from the collapse curves. It is evident from the results that the seismic performance of the proposed combined shear wall-damper system is significantly better than the models equipped with shear walls only. The scrutinized dual seismic resisting system is expected to be applied practically to ensure a multi-level shield for tall structures in high seismic risk zones.

• The Journal of Economics, Marketing and Management
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• v.11 no.3
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• pp.37-46
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• 2023

Purpose: The purpose of this study is to analyze the elderly friendliness of the serious game for dementia prevention and to seek out the influence factors for enhance the friendliness. Research design, data and methodology: It measured the elderly friendliness of the serious game for dementia prevention, run with multi-touchscreens, for 300 elderly people using the Seoul-based General Social welfare centers located at Seoul, and participants evaluated the elder-friendliness of the serious game, by responding to a questionnaire survey. In addition, it analyzed the influence relationship between the elderly friendliness (EF) and the influence factors of the serious game, by setting the factors as the game level (GL), the demand of expectations for demand (DoE) and the prevention & usefulness of cognitive decline (PUCD). Results: the findings show that most of participants positively evaluated the EF of the serious game, regardless of their socio-demographic characteristics. Moreover, it can be found that the more the 'GL DoE and PUCD', the more the 'EF'. The EF was most strongly affected by DoE, followed by PUCD, and then GL Developing and running the serious game by actively reflecting such factors may be one of ways for enhancing the participation in the serious game for dementia prevention and facilitating the sustainable use of it.

• Journal of Distribution Science
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• v.22 no.4
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• pp.91-104
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• 2024

Purpose: The study aims to assess the current status of domestic public food delivery apps and analyze the process through which sellers choose between private delivery apps and public delivery apps. This involves exploring strategiesto achieve the original purpose of public food delivery apps, which is to enhance the small business owners income and promote consumer welfare by preventing the monopoly of private food delivery apps. Research design, data and methodology: the research methodology is based on a model that introduces adjustments for non-economic effects, considering the preferences of multi-homing consumers, to more realistically reflect the benefits of sellers' choices. For data analysis, real business performance data from 'Daeguro', 'Meokkaebi', and 'Somunnan Shop' were used. Results: The study revealed that if the market share of public delivery apps within a specific region increases beyond a certain level, the benefits for small-business sellers also increase. This leads to the strategic advantage of simultaneously using both delivery apps. Furthermore, the results exhibit a tendency similar to real social phenomena. Conclusions: This analysis confirmed the role of public food delivery apps in the domestic delivery app market and presents policy recommendations, including application integration and the implementation of exclusive public interest functions, to effectively fulfill this role.

• Ocean Systems Engineering
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• v.14 no.1
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• pp.17-52
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• 2024

In this paper, the authors explore the modeling and control of a point absorber wave energy converter, which is connected to the electric grid via a power converter that is based on a linear permanent magnet synchronous generator (LPMSG). The device utilizes a buoyant mechanism to convert the energy of ocean waves into electrical power, and the LPMSG-based power converter is utilized to change the variable frequency and voltage output from the wave energy converter to a fixed frequency and voltage suitable for the electric grid. The article concentrates on the creation of a predictive control system that regulates the speed, voltage, and current of the LPMSG, and the modeling of the system to simulate its behavior and optimize its design. The predictive model control is created to guarantee maximum energy output and stable grid connection, using Matlab Simulink to validate the proposed strategy, including control side generator and predictive current grid-side converter loops.

• Therapeutic Science for Rehabilitation
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• v.9 no.3
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• pp.35-51
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• 2020

Objective : The purpose of this study was to develop and establish the preliminary validity of the Restaurant Accessibility and Task Evaluation Information Tool (RATE-IT), an electronic survey for evaluating restaurant accessibility for people with disabilities. Methods : A multi-phase method was used to develop and validate the RATE-IT. The taxonomy was developed in phase one, while the validity of the content was tested in phase two. Finally, the validity of the constructs was assessed in phase three. Results : The results indicated that appropriate items were included (relevance=0.99 and language level=0.99) and also supported that the RATE-IT evaluated the construct of restaurant accessibility (F=0.72, p=.40). When compared to a checklist of the Americans with Disabilities Act Accessibility Guidelines (ADAAG) for Buildings and Facilities questions, RATE-IT showed the potential to differentiate restaurants by their level of accessibility (p=.10). Further, the RATE-IT was also easy to use (p<.00), understandable (p<.00), and efficient (p<.00). Conclusion : RATE-IT shows a promising methodology and is strongly preferred by users.

• Korean Chemical Engineering Research
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• v.54 no.2
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• pp.239-247
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• 2016

This study aims to examine absorption characteristics of toluene, isopropyl alcohol (IPA), ethyl acetate (EA), and ternary-compounds, all of which are widely used in industrial processes, by means of four types of commercial activated carbon substances. It turned out that among the three types of volatile organic compounds, the breakthrough point of activated carbon and that of IPA, whose affinity was the lowest, were the lowest, and then that of EA and that of toluene in the order. With the breakthrough point of IPA, which was the shortest, as the standard, changes in the breakthrough points of unary-compounds, binary-compounds, and ternary-compounds were examined. As a result, it turned out that the larger the number of elements, the lower the breakthrough point. This resulted from competitive adsorption, that is, substitution of substances with a low level of affinity with those with a high level of affinity. Hence, the adsorption of toluene-IPA-EA and ternary-compounds require a design of the activated carbon bed based on the breakthrough of IPA, and in the design of activated carbon beds in actual industries as well, a substance whose level of affinity is the lowest needs to be the standard.