• Journal of the Korean Society of Radiology
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• v.85 no.1
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• pp.184-196
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• 2024

Purpose We investigated potentially promising imaging findings and their combinations in the evaluation of cognitive decline. Materials and Methods This retrospective study included 138 patients with subjective cognitive impairments, who underwent brain MRI. We classified the same group of patients into Alzheimer's disease (AD) and non-AD groups, based on the neuropsychiatric evaluation. We analyzed imaging findings, including white matter hyperintensity (WMH) and cerebral microbleeds (CMBs), using the Kruskal-Wallis test for group comparison, and receiver operating characteristic (ROC) curve analysis for assessing the diagnostic performance of imaging findings. Results CMBs in the lobar or deep locations demonstrated higher prevalence in the patients with AD compared to those in the non-AD group. The presence of lobar CMBs combined with periventricular WMH (area under the ROC curve [AUC] = 0.702 [95% confidence interval: 0.599-0.806], p < 0.001) showed the highest performance in differentiation of AD from non-AD group. Conclusion Combinations of imaging findings can serve as useful additive diagnostic tools in the assessment of cognitive decline.

• Geophysics and Geophysical Exploration
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• v.27 no.2
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• pp.108-118
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• 2024

In this study, expressions for the magnetic field and magnetic gradient tensor due to an elliptical disk were derived. Igneous intrusions and kimberlite structures often have elliptical cylinders with axial symmetry and elliptical cross sections. An elliptical cylinder with varying cross-sectional areas was approximated using stacks of elliptical disks. The magnetic fields of elliptical disks were derived using the Poisson relation, which includes the direction of magnetization in the gravity gradient tensor, as described in a previous study (Rim, 2024). The magnetic gradient tensor due to an elliptical disk is derived by differentiating the magnetic fields, which is equivalent to obtaining ten triple-derivative functions acquired by differentiating the gravitational potential of the elliptical disk three times in each axis direction. Because it is possible to exchange the order of differentiation, the magnetic gradient tensor is derived by differentiating the gravitational potential of the elliptical disk three times, which is then converted into a complex line integral along the closed boundary curve of the elliptical disk in the complex plane. The expressions for the magnetic field and magnetic gradient tensor derived from a complex line integral in complex plane are perfectly consistent with those of the circular disk derived from the Lipschitz-Hankel integral.

• Communications of Mathematical Education
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• v.38 no.2
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• pp.121-144
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• 2024

This study analyzes how the academic achievement of students in Korea changes as they transition from 4th grade of elementary school to 2nd grade of middle school, considering that the 4th graders in the previous TIMSS cycle become 2nd graders in the next cycle. In particular, this study selects and compares the eight main countries in the TIMSS math evaluation (Korea, Singapore, Taiwan, Japan, USA, UK, Australia, and Russia) to analyze the trend of change in academic achievement of Korean students according to school grade transition. The trend of change in academic achievement of students was analyzed not only overall but also by content area (number, geometry and measurement, data representation (data and probability/data and probability), gender, and regional scale. The analysis focused on the average score and the proportion of students by achievement level. The results of the study are as follows. First, there was no significant change in the average score of Korean students' academic achievement as the school grade transitioned, but the achievement gap widened in terms of the proportion by achievement level. Second, there were differences in students' academic achievement by content area according to school grade transition, and the pattern differed depending on the evaluation cycle. Third, there was a significant gap in students' math academic achievement depending on gender and regional scale of school location. This study reveals that the achievement gap among students in our country widens as they transition between school levels. The gap is found to vary in terms of achievement level, math content area, student gender, and school location. To alleviate these disparities, more substantial research and support are proposed in addition to policy implementation by the government or provincial offices of education.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.89-98
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• 2007

This study investigates the deformation behavior, related to debonding failure, of adhesion and repairing-strengthening materials of RC construction. A strain-stress curve shows that when the stress of specimens reached the highest and then fails, the strain value of cement mortar is $2.0{\times}10^{-3}$, while concrete was indicated at around $1.3{\times}10^{-3}$, epoxy resins are $0.8{\times}10^{-3}$, polymer mortar is $2.5{\times}10^{-3}$, steel plate is $2.5{\times}10^{-3}$, and carbon bar was $9.1{\times}10^{-3}$, respectively. For a thermal expansion coefficient with temperature variation, those basis materials, cement mortar and concrete, exhibited around $10{\mu}{\varepsilon}/{^{\circ}C}$, but adhesive materials, such as epoxy resins and polymer mortar, were $41{\sim}54{\mu}{\varepsilon}/{^{\circ}C}$ and $-0.5{\sim}0.7{\mu}{\varepsilon}/{^{\circ}C}$, respectively. In the case of steel plate is similar to basic materials but carbon fiber is indicates at $-1.7{\mu}{\varepsilon}/{^{\circ}C}$, which is the lowest value. Especially, between basic and adhesive materials, the thermal expansion coefficient was highly different. Although the coefficient depends on the type of epoxy resins, it is clear that the epoxy resins are susceptible to be debonded in nature, when the difference of environmental temperature varies more than $20{\sim}35{^{\circ}C}$.

• The Journal of the Convergence on Culture Technology
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• v.10 no.4
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• pp.23-31
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• 2024

The purpose of this study is to present the direction of teacher training to the future society by analyzing the key directions for teacher training announced by the Teacher Education and Training Department of the Ministry of Education for the past three years (2021, 2022, and 2023). The research results are as follows. First, there has been no change in the background for teacher training over the past three years. The background for the promotion of teacher training over the past three years is to increase teacher expertise, respond to the future environment, improve the quality of teacher training, and secure momentum for educational policy. The details of the background for the promotion have also remained unchanged over the past three years. Second, the teacher training vision for the past three years is innovation in the teacher training system. To this end, the vision is to lead changes in the future educational environment in 2021, to lead future public education in 2022, and to provide customized educational support for individual students in 2023. In terms of training goals, in 2021, the goal is to continuously develop professionalism appropriate for the life stage of teachers and enhance teacher core competencies suitable for the future educational environment, and in 2022, to strengthen teacher capabilities appropriate for the future education system and secure social trust through enhancing teacher training. In 2023, the focus is on changing classroom teaching through strengthening teacher capabilities suitable for the future education system and improving teacher training. There are three main directions for teacher training over the past three years. First, customized training support, second, strengthening the future training system, and third, improving teacher training. These three are all similar over the past three years. In conclusion, there has been no significant change in the direction of teacher training over the past three years.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.3
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• pp.361-373
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• 2024

Advertising on the exterior of buses was initiated in 1985 with the aim of generating operational funds for the 1988 Seoul Olympics. However, despite numerous technological advancements, the regulations governing the method (sheet attachment), area, and placement of exterior advertising on buses have remained unchanged to date. This has constrained the potential for profitability and efficiency in bus exterior advertising. According to Seoul Metropolitan Government, metro usage increased by 23 % in 2019 (prior to the COVID-19) compared to 2006, while bus usage decreased by 10 %. Consequently, financial subsidy for buses surged significantly over the past five years (2018-2022), averaging around KRW 450 billion, which is approximately 1.27 times the average for the preceding decade (2013-2022). The majority of revenue for bus transportation agencies is derived from passenger fares (81.1 %) and subsidies from Seoul City (17.5 %). Hence, it is imperative to enhance the share of revenue from sources other than fares. This study proposes an expansion of the role of bus exterior advertising by increasing the advertising area as a means to increase non-fare revenue. Two alternatives were proposed to expand the advertising area by 17 % and 94 %, respectively, compared to the current level, and their potential impacts were analyzed. The findings indicate that advertising revenue could increase from a minimum of KRW 3.2 billion to a maximum of KRW 53.9 billion, and public subsidies could be reduced by as much as 11.9 %. The bus exterior advertising can serve as an effective approach to diversify transportation revenue and decrease public subsidies.

• Sim-seong Yeon-gu
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• v.39 no.1
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• pp.1-60
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• 2024

This thesis originated from a dream of a young man clad in green, suspended like Christ on the stair landing. This dream reminded me of Jung's vision of the Christ on the Cross, bathed in a greenish gold aurum viriditas. Jung associated the analogy of Christ and aurum non vulgi, aurum viriditas of alchemy from this vision. I was fascinated by Jung's words that originally there were four alchemical stages, but by the 15th-16th century they were reduced to three (nigredo-albedo-rubedo); and that viriditas used to exist after nigredo had vanished. This thesis is about the process of unraveling these mysteries through amplification. In the realm of alchemy, viriditas (verdigris) was an old and humble substance, yet it would eventually metamorphose into pure gold under the supervision of alchemists. It was the prima materia of alchemical work and the ultimate product, mercurius itself. It was the celestial spirit, concealed beneath the earth, and the embodiment of transformation, enriching the earth, sprouting a myriad of buds and flowers, turning the land green. I examined the dreams, visions, and pictures of Hildegard of Bingen, C.G. Jung, my analysands, and my own to figure out whether viriditas was the fourth that leads to wholeness that engaged in the whole process of individuation. While working on this thesis, I learned that for our personalities to mature, we must include the lower, the secular, the feminine, the chtonic, and even the evil. To achieve this, we cannot avoid our opposite, the fourth, but to wait and persevere until we can walk together. Then, our lives will be fresh and blossoming.

• Industry Promotion Research
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• v.9 no.3
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• pp.295-309
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• 2024

With the implementation of the Northeast Revitalization Strategy, the tourism industry in Heilongjiang Province had an increasingly greater impact on regional economic development. Based on the tourism panel data of Heilongjiang Province from 2005 to 2021, this paper used DEA-BCC and Malmquist Index to analyze the static and dynamic changes of the tourism industry.The results of the study were as follows: (1) Static: The OE value reached strong DEA effectiveness in 2010, 2013, and 2019, indicated that tourism resources had been fully utilized. The SE value changed dramatically between 0.354 and 1, and the PTE value approached 1. OE was mainly affected by SE changes. (2) Dynamic: The total factor productivity (TFP) was overall greater than 1 and grew at an average annual rate of 13.8%. The variation in TFP was primarily influenced by the index of technological progress, indicated that the tourism industry in Heilongjiang Province made full use of technology for resource development, with a relatively high level of development efficiency. Therefore, the future focus of Heilongjiang Province's tourism industry will be on adjustments in industrial scale, technological innovation, and policy optimization.

• Journal of Digestive Cancer Research
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• v.8 no.2
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• pp.91-96
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• 2020

The effect of Helicobacter pylori (H. pylori) eradication on the development of metachronous recurrence after endoscopic resection (ER) of gastric adenoma is not well defined. The aim of this study was to assess the efficacy of H. pylori eradication after ER of gastric adenoma for the prevention of metachronous recurrence. A systematic literature review and meta-analysis were conducted using the databases Ovid-MEDLINE, EMBASE, Cochrane Library, KoreaMed, and KMBASE. Thus, a systematic review and meta-analysis was performed to investigate this relationship. Pooled risk ratio for metachronous gastric lesions with regard to H. pylori eradication was calculated, and heterogeneity was also measured. Five eligible studies were finally identified in systematic review, and included in meta-analysis. H. pylori eradication was associated with overall 55% lower odds of metachronous events (RR=0.55; 95 % CI 0.34-0.92). Based on the best available evidence, eradication of H. pylori can also provide protection against metachronous recurrence after ER of gastric adenoma.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.4
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• pp.13-20
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• 2024

In this study, when subjected to in-plane shear such as a shear wall, the behavior characteristics of a concrete member using CFRP rebars were investigated when the longitudinal reinforcement ratio was kept constant at 2.96% and the transverse reinforcement ratio was changed from 0.30 to 2.98%. The evaluation was conducted based on MCFT theory and analyzed by comparison with the case of concrete members using steel rebars. When the reinforcement ratio ranged from 0.30 to 1.19%, concrete members employing CFRP rebars exhibited higher shear strength compared to those using steel rebars. In contrast, at high reinforcement ratios of 1.79 and 2.98%, it was observed that the shear strength of the member with CFRP rebar was lower compared to the member with steel rebar. Maximum shear strain was observed to be higher for members reinforced with steel rebars at lower reinforcing bar ratios, while for ratios of 0.97% and above, CFRP rebars resulted in higher maximum shear strain. As the reinforcement ratio increases, the use of CFRP rebar instead of steel rebar results in a greater increase in maximum shear strain. By analyzing the difference in strain in the reinforcing bar as well as the difference in principal strain in the element caused by differences in the mechanical properties of the steel rebar and CFRP rebar, the shear strength and shear strain when using steel rebar and CFRP rebar with different reinforcement ratios can be compared and analyzed.