Kyungdong University

The original Brans-Dicke scalar-tensor gravity is believed to be attracted towards General Relativity with evolution of the Universe. In the presence of explicit scalar-matter direct coupling in the Brans-Dicke gravity, however, the attractor mechanism must be reconsidered. In this paper, the master equation found by Damour and Nordtvedt is rederived. It is shown that such a generalized master equation could modify the attraction to General Relativity and the scalar-matter direct coupling may accelerate or retard it. In original Brans-Dicke scalar-tensor gravity, the agent of the attraction to General Relativity is the gravitational coupling strength. However, in the presence of the scalar-matter direct coupling, the coupling function which characterizes the coupling of scalar field to matter, makes another potential associated with coupling and it produces a new coupling parameter in the existence of the scalar-matter direct coupling, the master equation which describes the evolution of scalar field, comes to have the force term of right hand side an additional term characterizing the scalar-matter coupling, i.e. the coupling parameter is lying in parallel with the strength parameter. Therefore, the attraction mechanism represented by the strength parameter alone comes to be modified by adding the new coupling parameter. The paper considered, in detail, the friction-dominated approximation which is a case of a negligible curvature of the scalar-curvature coupling potential. Then, depending on the sign of a new coupling parameter, the evolution of scalar field is shown to accelerate the attraction or to retard it. Consequently, the attraction towards General Relativity is modified on account of the scalar-matter direct coupling.

This study aimed to assess the in vitro biocompatibility of two types of three-dimensionally (3D)-printed resin crowns (RCs) for primary molars. Three types of crowns were tested: (i) stainless steel crowns (SSCs), (ii) prefabricated zirconia crowns (PZCs), and (iii) 3D-printed RCs, which included two types: DIOnavi-P. MAX (RC1), and NextDent C&B Micro Filled Hybrid (RC2). Human gingival fibroblast (HGF) cells were exposed to extracts obtained from the crowns. Cell viability, proliferation, and migration were evaluated using the Cell Counting Kit-8 assay, flow cytometry, and a scratch wound healing assay. Oxidative stress levels were analyzed using a reactive oxygen species (ROS) assay. Expression of inflammatory biomarkers was assessed using a nitric oxide assay and reverse transcription quantitative polymerase chain reaction, and further confirmed by Western blotting. RC groups had a limited effect on HGF cell viability, proliferation, and migration. ROS levels were significantly lower in the RC groups than in the lipopolysaccharide group (p < 0.05). No significant upregulation of inflammatory biomarkers was observed in the RC groups compared to the other crown groups (p > 0.05). Within the limits of this study, 3D-printed RCs showed biocompatibility. These findings highlight the possibility of the clinical application of 3D-printed RCs for primary molars. Our results support that 3D-printed RCs for primary molars can offer an esthetic option with biocompatibility in gingival tissues, causing minimal inflammation.

This study presents a small-scale hip exoskeleton incorporating bi-directional artificial muscles constructed with springs of Shape Memory Alloy (SMA). The prototype can effectively support hip motion in both extension and flexion, spanning an angular range of −20° to 200°. Experiments for thermo-mechanical characterization were executed to assess the performance of the SMA muscles throughout the entire motion range. The outcomes not only confirmed the suitability of the SMA muscles for the designed exoskeleton but also provided valuable insights into their behavior and capabilities. System identification experiments were carried out to establish an accurate transfer function, guiding the tuning of Proportional-Integral-Derivative (PID) controllers for enhanced motion-control effectiveness. The safety of the SMA system was addressed with a focus on preventing overheating. Challenges in accurately measuring the temperature of a thin spring were overcome by utilizing two thermocouples for each SMA springs group. Additionally, conventional SMA temperature measurement methods, such as infrared and resistance-based techniques, are limited by high cost, nonlinearity, and small range. This study presents a model-based temperature estimation algorithm that integrates a heat transfer model, electrical input data, and thermocouple data to enable accurate and real-time SMA temperature estimation without additional sensors, offering a cost-effective and reliable alternative. To evaluate the small hip prototype and its controller capabilities, control experiments were executed for both stepping and sinusoidal trajectories. The exoskeleton successfully tracked the desired trajectories, showing its precision. Moreover, system performance under adaptive control was further investigated, revealing an RMSE of 0.94° in sinusoidal trajectory experiments, indicating reliable disturbance rejection in the angle measurements.

This study was conducted to identify the Artificial intelligence ethical awareness, literacy, attitude, and knowledge levels of nursing students who will handle AI as future nurses and to confirm the correlation among them. The data for the study were collected through a structured questionnaire targeting 118 nursing students at K University in Gangwon-do, Korea in June 2025. The general characteristics of the subjects were calculated using frequencies and percentages, and the level of AI ethics awareness, literacy, attitude, and knowledge was calculated using means and standard deviations. The relationship among AI ethical awareness, literacy, attitude, and knowledge was analyzed using Pearson's Correlation Coefficient. The results of this study showed that AI ethics awareness had a positive correlation with AI literacy(r=.30, p&lt;.001), AI attitude(r=.42, p&lt;.001), and AI knowledge(r=.30, p&lt;.001), and AI literacy had a positive correlation with AI attitude(r=.35, p&lt;.001) and AI knowledge(r=.65, p&lt;.001). In addition, AI attitude had a positive correlation with AI knowledge (r=.27, p&lt;.001). In conclusion, when organizing the curriculum for AI education to improve the AI literacy ability of nursing students, it is necessary to include AI ethical awareness, attitude, and knowledge content. Since the ethical use of AI can protect patients from potential risks, various nursing educational approaches are needed regarding AI literacy and knowledge of nursing students.

The purpose of this study was to investigate the effects of nurses' emotional labor, sleep disorder, and company support on job stress. The research method used raw data from the 7th Work Environment Survey (2023), a public big data of Korea. The collected data were analyzed using the IBM SPSS/WIN 28.0 statistical program. Statistical analysis used t-test, ANOVA, and Pearson’s correlation coefficient. Multiple regression analysis was used to identify factors influencing the subjects' job stress. The subjects used data from 446 people who responded as “nurse” among all wage earners. The results revealed that the factors influencing the subjects' job stress were emotional labor (t=11.97, p=&lt;.001), company support (t=2.73, p=.006), and sleep disorder (t=1.99, p=.047). In conclusion, workplaces need measures to reduce nurses' sleep disorders and emotional labor to alleviate job stress, and measures to increase coworker and company support are required.

Tourism is a fundamental right, yet mobility-impaired Persons with Disabilities (PwDs) face significant barriers in Malaysia. This study explores their tourism experiences, highlighting challenges such as inadequate infrastructure, limited independence, and insufficient support from tourism providers. Using a qualitative phenomenological approach, four semi-structured online interviews were conducted. Findings reveal a need for accessible transport, accommodations, and inclusive event planning. Advocating for universal design principles and comprehensive accessibility guidelines, this study emphasizes the urgency of inclusive policies to ensure PwDs can travel with dignity, independence, and confidence, fostering a more equitable tourism landscape.

Methods: A total of 204 (90.7%) self-administered questionnaires were collected from den- tal technology students of K University in Gangwon-do for the final analysis.Using IBM SPSS Statistics version 21.0 (IBM), technical analysis, t-test, ANOVA, correlation analysis, and linear regression analysis were performed.Results: In regard to motivation for major choice, 'intrinsic motivation (3.48)' was slightly higher than 'extrinsic motivation (3.47)', in regards to major satisfaction, 'relationship satisfaction (4.14)' was the highest, in regards to adaptation to university life, 'social adjustment factors (3.79)' was the highest.Of the factors of satisfaction in major on the adaptation to university life, 'subject satisfaction factors (p<0.05)' and 'perception satisfaction factor (p<0.05)' were shown to have statistically significant relationships, and the explanatory power of the model was shown to be 44.6%. Conclusion:The results of this study indicate that dental technology students are highly motivated in selecting their major and show strong motivation to adapt to their major studies after admission.However, they would benefit from job shadowing opportunities with dental technologist and career lectures through various extracurricular programs starting from their first year to better facilitate their transition and future career paths.