• Journal of the Korean Society for Heat Treatment
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• v.37 no.4
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• pp.155-162
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• 2024

SCr420H steel which is commonly utilized for automotive components requires the carburizing heat treatment process. Abnormal grain growth during this treatment significantly affects the mechanical properties of the steel parts. Consequently, a process designed to prevent abnormal grain growth at certain elevated temperatures is essential. For enhanced grain refinement, we considered the addition of Nb in SCr420H steel. The experimental condition of the carburizing heat treatment involved reheating the steel sample to temperatures between 940℃ and 1080℃. Using scanning electron microscopy, we examined the microstructure of specimens treated with the secondary solution, revealing an organization of bainite and ferrite. Transmission electron microscopy was utilized to determine the type, shape, and size of the carbonitrides, showing a high fraction of AlN at the secondary solution treatment temperature of approximately 1050℃ and of (Nb,Ti)(C,N) around 1200℃. AlN particles measured about 100 nm and (Nb,Ti)(C,N) about 50 nm. Optical microscopy was utilized to assess grain size variations at different secondary solution treatment temperatures. It is noted that the temperature at which abnormal grain coarsening occurred rose with increasing secondary solution treatment temperatures, indicating a greater influence of (Nb,Ti)(C,N) with higher heat treatment temperatures. This research provides reference data for preventing abnormal grain growth in Nb-added low alloy steels undergoing carburizing heat treatment.

• Journal of the Korean Society for Heat Treatment
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• v.37 no.4
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• pp.163-171
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• 2024

SCR420H steel is a low-carbon chromium alloy steel designed for carburizing heat treatment. Recently, research is being conducted on high-temperature carburization heat treatment to reduce costs and CO₂ emissions by shortening the carburization time to meet the international carbon neutral policy. However, this high-temperature carburization heat treatment coarsens the steel grains and causes a decrease in mechanical properties. In this study, a large amount of Ti was added to increase the grain refinement effect in the high-temperature carburizing process. We investigated the microstructure and precipitates of SCR420H steel without Ti (Al steel) and with Ti (AlTi steel). Thermodynamic calculations showed that the AlN and (Ti,Nb)(C,N) precipitated in Al steel, while (Ti,Nb)(C,N) and Ti₄C₂S₂ precipitated in AlTi steel. Addition of Ti increases the fraction of bainite after reheating process. Transmission electron microscopy analysis shows that small amounts of AlN and (Ti,Nb)(C,N) precipitates are formed in the Al steel. The addition of Ti increases the density of (Ti,Nb)(C,N) precipitates and induces the formation of Ti₄C₂S₂ precipitates, increasing the grain coarsening temperature (GCT) under all heat treatment conditions. Higher reheating temperatures also resulted in higher GCT values due to increased precipitation.

• Journal of Internet Computing and Services
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• v.25 no.4
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• pp.109-119
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• 2024

This study aims to contribute to the initial research on on-device AI in an environment where generative AI-based services on mobile and other on-device platforms are increasing. To derive success strategies for generative AI-based chatbot services in a mobile environment, over 200,000 actual user experience review data collected from the Google Play Store were analyzed using the LDA topic modeling technique. Interpreting the derived topics based on the Information System Success Model (ISSM), the topics such as tutoring, limitation of response, and hallucination and outdated informaiton were linked to information quality; multimodal service, quality of response, and issues of device interoperability were linked to system quality; inter-device compatibility, utility of the service, quality of premium services, and challenges in account were linked to service quality; and finally, creative collaboration was linked to net benefits. Humanization of generative AI emerged as a new experience factor not explained by the existing model. By explaining specific positive and negative experience dimensions from the user's perspective based on theory, this study suggests directions for future related research and provides strategic insights for companies to improve and supplement their services for successful business operations.

• The Mathematical Education
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• v.63 no.3
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• pp.467-484
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• 2024

The rapid advancement of generative AI has ushered in an era where anyone can create and freely utilize personalized chatbots without the need for programming expertise. This study aimed to develop a customized chatbot based on OpenAI's GPTs for the purpose of pre-service teacher education and to analyze its educational performance in mathematics as assessed by educators guiding pre-service teachers. Responses to identical questions from a general-purpose chatbot (ChatGPT), a customized GPTs-based chatbot, and an elementary mathematics education expert were compared. The expert's responses received an average score of 4.52, while the customized GPTs-based chatbot received an average score of 3.73, indicating that the latter's performance did not reach the expert level. However, the customized GPTs-based chatbot's score, which was close to "adequate" on a 5-point scale, suggests its potential educational utility. On the other hand, the general-purpose chatbot, ChatGPT, received a lower average score of 2.86, with feedback indicating that its responses were not systematic and remained at a general level, making it less suitable for use in mathematics education. Despite the proven educational effectiveness of conventional customized chatbots, the time and cost associated with their development have been significant barriers. However, with the advent of GPTs services, anyone can now easily create chatbots tailored to both educators and learners, with responses that achieve a certain level of mathematics educational validity, thereby offering effective utilization across various aspects of mathematics education.

• Journal of Christian Education in Korea
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• v.78
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• pp.111-136
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• 2024

The purpose of this study is to theoretically explore symbol didactic, which serves as a mediator and integrator of human experience with biblical experience. Based on a deep consideration of the functions and roles of symbols, as studied in psychology, philosophy, religious studies, and theology, this study aims to examine representative theories of Bible didactic that have introduced symbolic action into Christian education. By exploring these theories, we aim to provide a comprehensive understanding of the role of symbols in Christian education and their impact on the learning process. This study is divided into two main parts. In the first half, it examines the meanings of symbols and their functions as discussed by prominent scholars from various disciplines who have paid attention to symbols, including S. Freud and C. Jung in psychoanalysis, E. Cassirer and P. Ricoeur in philosophy, M. Eliade in religious studies, and P. Tillich in theology. In the second half, the study critically analyzes and discusses representative theories of symbol didactic, such as those proposed by H. Halbfas and P. Biehl, which have applied the symbolic action of neighboring disciplines to Christian education. Symbol didactic differs from traditional biblical didactic, which aims to transmit content, by using symbols as a medium to facilitate dialogue between the learner's experiences and those of the Bible. This approach enables learners to experience the deep relationship between the content of the Bible and the experiences of biblical figures with their own experiences, and provides an opportunity to deepen that experience.

• Herbal Formula Science
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• v.32 no.2
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• pp.155-179
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• 2024

Objective : Danggwisu-san (DGSS) is an herbal formula that has been mainly used in the East Asia for the treatment of bruise, sprain and external injury. The cause of this pain is that Qi and blood become tangled and do not circulate well. DGSS can improve the tangled situation and make it well-circulated. The present study evaluated the anti-inflammatory effects of DGSS on Raw 264.7 cells and in rats with paw edema. Methods : Cell viability was measured using the MTT assay. The amount of nitric oxide (NO) production was measured the amount of nitrite content in the cultured medium using Griess reagent. The amount of tumor necrosis factor-α, monocyte chemoattractant protein 1, interleukin (IL)-1βand IL-6 in the cultured supernatant were measured by ELISA kit. Proteins expression were detected by Western blot. Furthermore, the effect of DGSS on acute inflammation was observed in rat paw edema model. Results : The DGSS ameliorates the lipopolysaccharide-activated changes in NO production, iNOS expression and pro-inflammatory cytokines. Additionally, DGSS significantly suppressed expression of p-JNK, p-ERK and nuclear NF-κB. As expected, in rat paw edema study, 1.0 g/kg of DGSS significantly reduced the carrageenan-induced paw edema and iNOS expression for 1-4 h. Moreover, administration of 1.0 g/kg (4 days) of DGSS used in this study did not show any significant change on ALT and AST. Conclusion : These results demonstrate that DGSS has anti-inflammatory effects in vitro and in vivo. Therefore, this present study can put scientific evidences up for the anti-inflammatory effect of DGSS.

• Korean Journal of Culture and Social Issue
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• v.30 no.3
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• pp.267-298
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• 2024

Childcare support for working mothers is crucial for women's smooth transition into society, career development, and well-being. Based on interviews with 10 Korean working mothers with children aged 0-2, this paper explores the process of utilizing childcare support services, psychological experiences, and plans for work-life balance using the grounded theory analysis method. The analysis revealed three categories: the decision-making process before using the childcare services (past), experiences during the use of childcare support (present), and future plans for work-life balance (future). The decision-making process before using childcare support services consisted of the following categories: seeking information about childcare support services, having family discussions during the decision-making process, the proposer and decision-maker of the services, and the final decision on childcare support services. Experiences during the use of services included economic burdens, changes in postnatal career paths, disparities between expectations and the reality of pre- and post-childbirth, discrepancies between expectations and reality in work-family balance, factors affecting of quality of life, and the division of household and childcare responsibilities with husbands. Plans for future work-life balance included categories such as the desire for career advancement, the desire to maintain a career, the desire for temporary or reduced career commitment, and uncertainty regarding future career plans. Finally, the study investigated whether there were differences in the past and present service usage processes and experiences based on plans for future work-life balance. This research suggests the need for multidimensional support for working mothers' work-family balance and well-being, and highlights the need to reduce uncertainty about women's future careers.

• 유학연구
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• v.48
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• pp.333-360
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• 2019

The present study attempts to shed new light on Wang Yang-Ming's(王陽明, 1472-1528) Mind-Heart Learning(心學) by using "empathy" as a key word. In order to review Wang Yang-Ming's Mind-Heart Learning with the keyword of "empathy," the study will first examine the empathetic nature of "Liang-zhi(良知)", which is the essence of Wang Yang-Ming's Mind-Heart Learning. The concept of "Liang-zhi" is closely related to Wang's organic worldview, in which he sees the entire universe as one whole organism. In Wang's philosophy, "Ren(仁)" means the the will to life : the virtue of nature that provides the basis of the unimpeded communication of life force among all beings in the universe. Thus, his philosophy emphasizes that "Ren(仁)" is the ceaseless and dynamic life-generating foundation that serves as the fundamental life force and principle that pervades nature and human beings. According to Wang, Ren(仁), which is the principle of life that creates and nurture the whole universe of sky, earth, and nature, is an innate quality of all human beings who exist as part of the nature. In this context, empathy can be seen as an essential feature that characterizes Wang's Mind-Heart Learning(心學). According to Wang, there is a close relation between human nature and various emotional states or feelings which modern psychology or counseling psychology mainly deals with-anxiety, worry, pleasure, enjoyment, and sense of security. By making a close connection between the realization of good nature and emotion, Wang can be said to have integrated The essence of human nature and the essence of heart. In this way, his philosophy argues that people are led to act morally not by obligation or enforcement imposed on them by others but by vitality and joy belonging to the innate quality of human heart. Based on this basic understanding of "empathy" in Wang's Mind-Heart Learning(心學), the present study will bring to the fore some aspects of empathy such as moral sensibility, driving force for self-fulfillment, integrated intelligence, and practical ways to realize innate goodness.

• CHINESE LITERATURE
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• v.100
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• pp.85 -100
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• 2019

In the 21st century, there was a boom of research in the field of Taiwanese historical narrative on Netherland's colonial rule of Taiwan in the 17th century. Such trend expanded to the literature field, and creations were made using the forgotten historical material. Representative works are 《婆 娑之島》 and 《福爾摩沙三族記》, written by Ping Lu and Chen Yao-chang. By analyzing these texts, this study studies what kind of a message the author presents through the literary form, and what his view is on the present and the future. In 《婆娑之島》, Ping Lu presents the fate of Taiwan being in the midst of imperialism for 400 years, and points out the betrayal of imperialism on Taiwan. Ping Lu argues that in order for Taiwan to evade from such situation, the future of Taiwan should be discussed in the global context, outside of the limited perspective of "China/Taiwan". Chen Yao-chang established the Tiwanese identity based on the multiple history narrative, by referencing to the spacial identity instead of the innate kinship. Such establishment of identity gave a breakthrough to the identity politics in Taiwan. Amidst the rapidly changing world politics and economy, it is essential for Taiwan to reestablish the cultural identity for itself for its development. What is more important is that the multiple history narrative maintains openness of history and communicates with the grand narrative to prevent history from being baised.

• The Korean Journal of Archival Studies
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• no.82
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• pp.47-86
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• 2024

The role of the archive providing the service is crucial for making records more widely known and utilized. The personal letters exchanged between Moon Ik-hwan and Park Yong-gil are unique personal records that fill the gaps left by public records during the politically tumultuous period of the early 1980s in Korea. This paper aims to shed light on the context of record management by comprehensively analyzing these letters in terms of their interrelationships. To achieve this, the study analyzes the context of 694 letters exchanged between the two during Moon Ik-hwan's imprisonment in the third prison following the Kim Dae-jung Conspiracy Case. The research methodology involved reviewing literature and records to summarize the historical context and personal backgrounds, and a comparative analysis was conducted to reveal the interrelationships and meanings within the texts of the letters. The findings of this study can be summarized into three key points. First, the paper outlines the shared context of the letters by summarizing the political and social circumstances of the time, particularly focusing on the Kim Dae-jung Conspiracy Case, and the characteristics of individual relationships. Second, it distinguishes the direct methods of letter exchange, categorizing them into routine and atypical methods, and identifies the relationships between the letters, the flow of dialogue within them, and their distinctive features. Third, it explores the interrelations and meanings between the contents of the letters. Through this analysis, it was confirmed that the two sets of letters, as a unified and expansive text, display characteristics of integration, competition, and expansion in their content. This analysis emphasizes the importance of understanding the context of letters in record management and demonstrates the need for archives to provide rich contextual information when offering access to letters.