• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.214-224
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• 2024

Valves play an essential role in a chemical plant such as regulating fluid flow and pressure. Therefore, optimal selection of the valve size and type is essential task. Valve size and type have been selected based on theoretical formulas about calculating valve sizing coefficient (Cv). However, this approach has limitations such as requiring expert knowledge and consuming substantial time and costs. Herein, this study developed a model for predicting valve sizes and types using machine learning. We developed models using four algorithms: ANN, Random Forest, XGBoost, and Catboost and model performances were evaluated using NRMSE & R² score for size prediction and F1 score for type prediction. Additionally, a case study was conducted to explore the impact of phases on valve selection, using four datasets: total fluids, liquids, gases, and steam. As a result of the study, for valve size prediction, total fluid, liquid, and gas dataset demonstrated the best performance with Catboost (Based on R², total: 0.99216, liquid: 0.98602, gas: 0.99300. Based on NRMSE, total: 0.04072, liquid: 0.04886, gas: 0.03619) and steam dataset showed the best performance with RandomForest (R²: 0.99028, NRMSE: 0.03493). For valve type prediction, Catboost outperformed all datasets with the highest F1 scores (total: 0.95766, liquids: 0.96264, gases: 0.95770, steam: 1.0000). In Engineering Procurement Construction industry, the proposed fluid-specific machine learning-based model is expected to guide the selection of suitable valves based on given process conditions and facilitate faster decision-making.

• Korean Chemical Engineering Research
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• v.62 no.3
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• pp.225-232
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• 2024

The reduction of CO₂ emissions in the energy production sector, which accounts for 86.8% of total greenhouse gas emissions, is important to achieve carbon-neutrality. At present, 60% of total power generation in South Korea is coal and natural gas. Replacing fossil fuel with renewable energy such as wind and solar has disadvantages of unstable energy supply and high costs. Therefore, this study was conducted through the co-firing of natural gas, ammonia and hydrogen utilizing the natural gas combined cycle process. The results demonstrated reduction in CO₂ emissions and 34%~238% of the power production compared to using only natural gas. Case studies on mass fractions of natural gas, ammonia and hydrogen indicated that power production and NO_x emissions were inversely proportional to the ammonia ratio and directly proportional to the hydrogen ratio. This study provides guidelines for the use of various fuel mixtures and economic analysis in co-firing power generation.

• Journal of Christian Education in Korea
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• v.75
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• pp.59-81
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• 2023

Purpose of study: The purpose of this study is to analyze the experience of writing a learning reflection journal, identify the effects, and propose an effective learning reflection journal activity way. Research content and method: This study examined the theoretical background of the concept and educational effect of the learning reflection journal through literature review in terms of educational and Christian educational aspects, and analyzed the learning reflection journal experience through the interviews with six students. Through this, this study identifies the effectiveness of the learning reflection journal and suggests effective learning reflection journal activity way that can be applied to training that can grow as a Christian educator who practices what he or she know through major classes. Conclusions and Suggestions: For effective learning reflection journal activities, it was proposed to reduce the number of review and reflection questions so that they would not be burdensome, to include questions in a balanced way, to help learners to improve class attitudes. It was also proposed that the submission period and the number of writing journals should be agreed upon with the students at the beginning of the semester.

• 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 the Korea Computer Graphics Society
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• v.30 no.3
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• pp.149-158
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• 2024

Photo booths have traditionally provided a fun and easy way to capture and print photos to cherish memories. These booths allow individuals to capture their desired poses and props, sharing memories with friends and family. To enable diverse expressions, generative AI-powered photo booths have emerged. However, existing AI photo booths face challenges such as difficulty in taking group photos, inability to accurately reflect user's poses, and the challenge of applying different concepts to individual subjects. To tackle these issues, we present CINEMAPIC, a photo booth system that allows users to freely choose poses, positions, and concepts for their photos. The system workflow includes three main steps: pre-processing, generation, and post-processing to apply individualized concepts. To produce high-quality group photos, the system generates a transparent image for each character and enhances the backdrop-composited image through a small number of denoising steps. The workflow is accelerated by applying an optimized diffusion model and GPU parallelization. The system was implemented as a prototype, and its effectiveness was validated through a user study and a large-scale pilot operation involving approximately 400 users. The results showed a significant preference for the proposed system over existing methods, confirming its potential for real-world photo booth applications. The proposed CINEMAPIC photo booth is expected to lead the way in a more creative and differentiated market, with potential for widespread application in various fields.

• Journal of Science Education
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• v.48 no.2
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• pp.75-90
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• 2024

Contemporary society faces increasingly diverse risks with expanding impacts. In response, the importance of science education has become more prominent. This study aims to analyze the characteristics of existing research on science-related risk education and derives implications for such education. Using detailed bibliometric analysis, we collected citation data from 83 international scholarly journals (SSCI) in the field of education indexed in the Web of Science with the keywords 'Scientific Risk.' Subsequently, using the bibliometrix package in R-Studio, we conducted a bibliometric analysis. The findings are as follows. Firstly, research on risk education covers topics such as risk literacy, the structure of risks addressed in science education, and the application and effectiveness of incorporating risk cases into educational practices. Secondly, a significant portion of research on risks related to science education has been conducted within the framework of socioscientific issues (SSI) education. Thirdly, it was observed that research on risks related to science education primarily focuses on the transmission of scientific knowledge, with many studies examining formal education settings such as curricula and school learning environments. These findings imply several key points. Firstly, to effectively address risks in contemporary society, the scope of risk education should extend beyond topics such as nuclear energy and climate change to encompass broader issues like environmental pollution, AI, and various aspects of daily life. Secondly, there is a need to reexamine and further research topics explored in the context of SSI education within the framework of risk education. Thirdly, it is necessary to analyze not only risk perception but also risk assessment and risk management. Lastly, there is a need for research on implementing risk education practices in informal educational settings, such as science museums and media.

• Journal of Korea Water Resources Association
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• v.57 no.9
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• pp.585-598
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• 2024

To mitigate natural disasters and efficiently manage water resources, it is essential to enhance hydrologic prediction while reducing model structural uncertainties. This study analyzed the impact of lumped and semi-distributed GR4J model structures on simulation performance and evaluated uncertainties with and without data assimilation techniques. The Ensemble Kalman Filter (EnKF) and Particle Filter (PF) methods were applied to the Namgang Dam basin. Simulation results showed that the Kling-Gupta efficiency (KGE) index was 0.749 for the lumped model and 0.831 for the semi-distributed model, indicating improved performance in semi-distributed modeling by 11.0%. Additionally, the impact of uncertainties in meteorological forcings (precipitation and potential evapotranspiration) on data assimilation performance was analyzed. Optimal uncertainty conditions varied by data assimilation method for the lumped model and by sub-basin for the semi-distributed model. Moreover, reducing the calibration period length during data assimilation led to decreased simulation performance. Overall, the semi-distributed model showed improved flood simulation performance when combined with data assimilation compared to the lumped model. Selecting appropriate hyper-parameters and calibration periods according to the model structure was crucial for achieving optimal performance.

• Journal of The Korean Society of Integrative Medicine
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• v.12 no.3
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• pp.163-178
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• 2024

Purpose : This study aimed to evaluate the effectiveness of an integrative medical service model applied to breast cancer patients and their caregivers, exploring its feasibility and challenges within the context of South Korean healthcare system. Methods : A case study approach was chosen to assess the integrative medical service model's efficacy, involving one breast cancer patient and her primary caregiver from W University Hospital. The patient had completed reconstructive surgery and chemotherapy and was undergoing radiotherapy. The model included standard treatments alongside psychological counseling, aromatherapy, axillary rehabilitation exercise, make-up program, art therapy, laughter therapy, horticultural therapy, and yoga programs, and meditation programs delivered over eight weeks. Quantitative and qualitative data were collected through surveys, psychological tests, and feedback assessments. Results : The integrative medical service model demonstrated notable improvements in the quality of life for both breast cancer patients and their caregivers. Participants reported enhanced emotional well-being, reduced stress levels, and improved coping mechanisms throughout the treatment journey. Qualitative feedback highlighted the positive impact of holistic interventions in alleviating psychological distress and fostering resilience. Quantitative data corroborated these findings, showing statistically significant improvements in various psychosocial parameters assessed. Conclusions : Our findings underscore the benefits of integrative medical service model with standard medical treatments in the care of breast cancer patients and their caregivers. The holistic approach not only addresses physical symptoms but also enhances overall well-being and quality of life. However, the implementation of such models faces challenges within the South Korean healthcare system, including fragmented service networks and financial constraints. Addressing these structural barriers is crucial for the widespread adoption and sustainability of integrative care models in oncology practice. Future research should focus on larger-scale studies to further validate these findings and inform policy decisions aimed at optimizing cancer care delivery.

• Korean Journal of Environment and Ecology
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• v.38 no.4
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• pp.405-415
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• 2024

The bioacoustics generated in urban parks contribute to the overall sound diversity of a city, creating a harmonious acoustic environment and maintaining the balance of the soundscape. However, due to the rapid urbanization process, the acoustic environment in urban parks is continuously deteriorating due to increased noise. In this study, we present an approach to monitoring the acoustic environment of urban parks by analyzing the soundscape of Namsan Urban Natural Park in Seoul. Acoustic data were collected continuously for one month from August 2021 in four facility districts of the study site using autonomous recording units, and a total of 2,784 hours of sound material were obtained. We also compared soundscape characteristics over time in each district using acoustic indices (ACI, ADI, BI, NDSI) representing soundscape complexity, acoustic diversity, degree of bioacoustics, and anthropogenic disturbance. The results showed that acoustic indices related to bioacoustics varied between districts, but most indices showed similar variation patterns due to the influence of anthropogenic sounds. In particular, regional differences closed during periods of high bird activity but not during periods of high human activity. We suggest that considering both acoustic characteristics and multiple acoustic indices is necessary for managing the soundscape of urban parks. The results of this study are expected to provide essential data for assessing the health of urban ecosystems based on soundscapes and to be used for monitoring the acoustic environment of urban parks.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.253-260
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• 2024

This study aims to analyze the key legal issues of the Serious Accidents Punishment Act (SAPA), which came into effect on 2022, in South Korea, and to propose practical occupational safety and health management strategies for business executives. The SAPA was introduced to prevent serious industrial accidents and protect workers' lives and safety. However, its effectiveness has been controversial due to the ambiguity of the law and uncertainty in its application. The study first provides an overview of the SAPA's main provisions and analyzes legal issues focusing on the punishment of business executives and the punitive damages system. Key issues identified include the ambiguity of "safety and health obligations," difficulties in proving causality, and unclear criteria for determining intent or gross negligence. Recent cases of serious accidents are examined to illustrate practical challenges in applying the law. Furthermore, the study compares the punitive damages system under the SAPA with that of the Product Liability Act and similar systems in the United States, United Kingdom, and Germany. This comparative analysis highlights the characteristics and problems of the Korean system, such as the unclear punitive nature, controversy over excessive compensation, and potential for abuse of litigation. Finally, the study proposes practical occupational safety and health management strategies for business executives to effectively respond to the SAPA and create safer workplaces. Key strategies include establishing a safety and health management system, conducting risk assessments, implementing safety education, managing subcontractor safety, and investing in safety and health.