• Analyses & Alternatives
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• v.6 no.2
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• pp.37-78
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• 2022

The U.S.-led international order, sustained by overwhelming national power since the end of the Cold War, is gradually being restructured from a unipolar international system to a bipolar international system or a multipolar international system, coupled with the weakening of U.S. global leadership and the rise of regional powers. Geopolitically, discussions have been constantly raised about the security instability that the reshaping of the international order will bring about, given that East Asia is a region where the national interests of the United States and regional powers sharply overlap and conflict. This study aims to critically analyze whether security discussions in Korea are based on appropriate crisis assessment and evaluation. This paper points out that the security crisis theory emerging in Korea tends to arise due to threat exaggeration and emphasizes the need for objective evaluation and conceptualization of the nature and the level of threats that the restructured international order can pose to regional security. Based on the analysis of changes in conflict patterns (frequency and intensity), occurring in East Asia during the periods divided into a bipolar system (1950-1990), a unipolar system (1991-2008), and a multipolar system (2009-current), this study shows that East Asia has not been as vulnerable to power politics as other regions. This investigation emphasizes that the complexity of Korea's diplomatic and security burden, which are aggravated by the reorganization of the international order, do not necessarily have to be interpreted as a grave security threat. This is because escalating unnecessary security issues could reduce the diplomatic strategic space of the Republic of Korea.

• Journal of The Korean Society of Integrative Medicine
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• v.10 no.3
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• pp.85-94
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• 2022

Purpose : This study aimed to investigate the effects of 12 weeks of resistance exercise on body composition, physical strength, blood lipids, and insulin. Methods : The study was conducted on 24 elderly women divided into two groups: 12 subjects in an exercise group and 12 subjects in a control group. Resistance exercise was performed for 50 minutes a day, three times a week, for the duration of 12 weeks, and body composition, physical strength, blood lipids, and insulin were measured before and after the subjects completed the program. For the statistical analysis, the mean and standard deviation (M±SD) of each variable were calculated using SPSS version 20, and a paired t-test and two-way repeated ANOVA were conducted to test for the differences before and after the resistance exercise. All significant levels were set to α=.05 as a result of the experiment. Results : Changes in body composition after the 12-week resistance exercise program did not show any significant difference based on the comparison between the groups, but when noting the values for body fat percentage and body in the control group before and after, a significant difference was shown in fat mass (p<.05). As for changes in physical fitness, significant differences appeared in flexibility, muscle strength, and stenotic force (p<.01) when the groups were compared. Regarding pre- and post-values within each group concerning flexibility within the exercise group, significant differences were shown in gender (p<.001), muscle strength (p<.05), (p<.01), muscle earth strength, equilibrium (p<.01), stenosis force, and cardiopulmonary earth force (p<.001). Also, comparisons between populations in changes in blood lipids the values before and after in each group, significant differences in glucose (p<.05) and insulin (p<.05) were shown in the exercise group. When comparing the values before and after in each population, a significant difference was shown in the control group (p<.05). Conclusion : When all the results were integrated, the 12-week resistance exercise program was found to enhance physical strength (flexibility, muscle strength, and coordination) and improve the blood sugar levels of elderly women. In particular, resistance exercise is believed to lower the prevalence of obesity, type 2 diabetes mellitus, and metabolic diseases by having a positive effect on insulin. Further studies are suggested to verify the effect on body composition and blood lipids by setting up a variety of exercise treatment methods (including subjects, exercise periods, exercise plans, and exercise intensity focuses).

• Health Policy and Management
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• v.4 no.1
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• pp.49-76
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• 1994

Small area variations in health care utilization have long been studied as an important issue related to boto cost containment and quality assurance. This study was conducted to investigate if variations in hospital services across small geographic areas in Korea existed. The claims data of the fiscal year 1992 obtained from the regional health insurance societies were used for the study. Main findings of the research can be summarized as follows : 1. Extremal Quotients(EQ) of hospital expenditure per capita and hospital days per capita varied among diagnosis types. The EQ ranged from 2.05(cataract) to 41.67(pneumonia) in hospital expenditure per capita and from 1.86(cataract) to 45.89(pneumonia) in hospital days per capita. The diagnosis groups which showed high variation were pneumonia, cephalo-pelvic disproportion, gastritis and duodenitis, fracture of rib, and acute bronchitis. Those which showed low variation were acute appendicitis and cataract. 2. The EQ level of admission rate was different in terms of diagnosis types, ranging from 2.57(catarct) to 44.45(pneumonia). The variations were high in medical disorders such as pneumonia, oephalo-pelvic disproportion, gastritis and duodenitis and acute bronchitis, while relatively low in surgical conditions such as acute appendicitis and cataract. 3. As an indicator of service intensity, the EQ of expenditure per admission ranged from 1.67(acute appendicitis) to 31.27(essential hypertension). The diagnoses which had high variation were essential hypertension, gastric ulcer, whereas those which had low variation were cephalopelvic disproportion and acute appendicitis. With regard to hospital days per admission, the EQ ranged from 1.55(acute appendicitis) to 28.13(gastric ulcer) by diagnosis types. The diagnosis groups with showed high variation were gastric ulcer, essential hypertension, and acute bronchitis, whereas those with low variation were cephalo-pelvic disproportion, intervertebral disc disorders, and acute appendicitis. Both the expenditure and hospital days per admission showed lewwer variations than the expenditure per capita, hospital days per capita and admission rate. 4. Comparing patterns of variation in utilization indices, diagnoses such as essential hypertension, gastric ulcer, fracture of rib showed higher variations in expenditure per admission than in admission rates, whereas diagnoses such as pneumonia, cephalo-pelvic disproportion and gastric ulcer showed higher variations in admission rate than expenditure per admission. These findings suggest that wide variations existed in several diagnoses groups across small areas in Korea. Further research should be performed to investigate factors related to small area variations including provider behavior.

• Korean Journal of Culture and Social Issue
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• v.29 no.1
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• pp.1-23
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• 2023

The purpose of this study was to validate the Suicidal Ideation Attributes Scale(SIDAS) which can measure the severity of suicidal ideation in a sample of 399 Korean adults. For this purpose, an online survey was conducted for two weeks from July 2020 to August 2020. First, there were differences in SIDAS scores among groups divided by gender, residence status, depression and anxiety symptoms, suicidal ideation, suicidal plan, suicidal preparation, and suicidal attempt. Second, correlations between SIDAS, C-SSRS suicidal ideation intensity question(3 items), and the Rosenberg Self-efficacy (RSE) were examined to confirm the validity of SIDAS. As a result, correlations between the SIDAS and suicidal ideation intesity items of C-SSRS were significant in all items, while correlations between the SIDAS and RSE items were negative or insignificant. Third, as a result of the confirmatory factor analysis of SIDAS on all respondents and respondents with suicidal ideation, a single factor structure was appropriate for both groups. Internal consistency of SIDAS was also good. Lastly, as a result of identifying the variables affecting the suicidal plan over the past year, controllability and age were identified as significant predictive variables. SIDAS which was designed to be administered through web, can be appropriately used in Korea. It was confirmed that SIDAS is a reliable and valid suicidal ideation scale which is applicable to adults in Korea.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.1
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• pp.1-16
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• 2023

A non-rare earth-based strontium-aluminate red light emitting phosphor was synthesized by a solid-state reaction method and the effect of synthesis temperature and Mn⁴⁺ activator concentration on the photoluminescence characteristics of the phosphor was studied. The synthesized SrAl₂O₄:Mn⁴⁺ phosphor showed broad band absorption characteristics in the near-ultraviolet and blue regions with peaks at wavelengths of near 330 and 460 nm, and a triple band deep red emission consisted of three peaks at near 644, 658, and 673 nm. The SrAl₂O₄:Mn⁴⁺ phosphor synthesized at a temperature 1600℃ and a Mn⁴⁺ activator concentration of 0.5 mol% showed the strongest PL emission intensity, and concentration quenching was observed at concentrations higher than 0.7 mol%. FE-SEM and DLS particle size distribution analysis showed that the synthesized SrAl₂O₄:Mn⁴⁺ phosphor had a particle size distribution of 2~6.4 ㎛ and an irregular spherical shape with an average particle size of ~4 ㎛.

• Korean Journal of Optics and Photonics
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• v.34 no.1
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• pp.1-12
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• 2023

In this study, we propose a hybrid phase-control algorithm for multi-channel coherent beam combining (CBC) system by combining the covariant matrix adaption evolution strategy (CMA-ES) and stochastic parallel gradient descent (SPGD) algorithms and analyze its operational performance. The proposed hybrid CMA-ES/SPGD algorithm is a sequential process which initially runs the CMA-ES algorithm until the combined final output intensity reaches a preset interim value, and then switches to running the SPGD algorithm to the end of the whole process. For ideal 7-channel and 19-channel all-fiber-based CBC systems, we have found that the mean convergence time can be reduced by about 10% in comparison with the case when the SPGD algorithm is implemented alone. Furthermore, we analyzed a more realistic situation in which some additional phase noise was introduced in the same CBC system. As a result, it is shown that the proposed algorithm reduces the mean convergence time by about 17% for a 7-channel CBC system and 16-27% for a 19-channel system compared to the existing SPGD alone algorithm. We expect that for implementing a CBC system in a real outdoor environment where phase noise cannot be ignored, the hybrid CMA-ES/SPGD algorithm proposed in this study will be exploited very usefully.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.191-199
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• 2023

This study aimed to propose minimized radiation doses with an optimized abdomen x-ray image, which realizes a Deep Blind Image Super-Resolution Generative adversarial network (BSRGAN) technique. Entrance surface doses (ESD) measured were collected by changing exposure conditions. In the identical exposures, abdominal images were acquired and were processed with the BSRGAN. The images reconstructed by the BSRGAN were compared to a reference image with 80 kVp and 320 mA, which was evaluated by mean squared error (MSE), peak signal-to-noise ratio (PSNR), and structural similarity index measure (SSIM). In addition, signal profile analysis was employed to validate the effect of the images reconstructed by the BSRGAN. The exposure conditions with the lowest MSE (about 0.285) were shown in 90 kVp, 125 mA and 100 kVp, 100 mA, which decreased the ESD in about 52 to 53% reduction), exhibiting PSNR = 37.694 and SSIM = 0.999. The signal intensity variations in the optimized conditions rather decreased than that of the reference image. This means that the optimized exposure conditions would obtain reasonable image quality with a substantial decrease of the radiation dose, indicating it could sufficiently reflect the concept of As Low As Reasonably Achievable (ALARA) as the principle of radiation protection.

• Membrane and Water Treatment
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• v.14 no.3
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• pp.129-140
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• 2023

The appropriate injection of H₂O₂ is essential to produce hydroxyl radicals (OH·) by mixing H₂O₂ quickly and exposing the resulting H₂O₂ solution to UV irradiation. This study focused on evaluating mixing device of H₂O₂ as a design factor of UV/H₂O₂ AOP pilot plant using a surface water. The experimental investigation involved both experimental and model-based analyses to evaluate the mixing effect of different devices available for the H₂O₂ injection of a tubular hollow pipe, elliptical type of inline mixer, and nozzle-type injection mixer. Computational fluid dynamics analysis was employed to model and simulate the mixing devices. The results showed that the elliptical type of inline mixer showed the highest uniformity of 95%, followed by the nozzle mixer with 83%, and the hollow pipe with only 18%, after passing through each mixing device. These results indicated that the elliptical type of inline mixer was the most effective in mixing H₂O₂ in a bulk. Regarding the pressure drops between the inlet and outlet of pipe, the elliptical-type inline mixer exhibited the highest pressure drop of 15.8 kPa, which was unfavorable for operation. On the other hand, the nozzle mixer and hollow pipe showed similar pressure drops of 0.4 kPa and 0.3 kPa, respectively. Experimental study showed that the elliptical type of inline and nozzle-type injection mixers worked well for low concentration (less than 5mg/L) of H₂O₂ injection within 10% of the input value, indicating that both mixers were appropriate for required H₂O₂ concentration and mixing intensity of UV/ H₂O₂ AOP process. Additionally, the elliptical-type inline mixer proved to be more stable than the nozzle-type injection mixer when dealing with highly concentrated pollutants entering the UV/H₂O₂ AOP process. It is recommended to use a suitable mixing device to meet the desired range of H₂O₂ concentration in AOP process.

• Journal of the Korean Geotechnical Society
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• v.22 no.5
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• pp.83-91
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• 2006

Recently, the intensive rainstorm possibly induced by global warming plays a key role on the instability of railway adjacent slopes. The instability of slopes results as covering and loss of railway lines induced by slided soil mass. According to the site investigation on the failed slopes triggered by rainfall, low types of slope failure were observed: shallow, intermediate, gully erosion, and soil-rock interface failures. The observation reveals the different characteristics of slope failure depending on the thickness of soil layer, morphological features of slope, etc. Based upon the observations, flume tests were conducted to analyze the sliding mechanism of each failure. The variables of flume test are soil layer thickness, rainfall intensity, and morphology of slope under the constant condition of the percentage of fine, initial soil moisture content, slope angle and compaction energy. Test results show that shallow failure was mostly observed from the surface of the slope and caused by the soil erosion; in addition, compared to the other types of failure, the occurrence of initial erosion is late, however, the development of erosion is fast. In gully erosion failure, the collected water from the water catchment area helps erosion of the upper soil layer and transfer of residual corestone, which impedes the erosion process once the upper soil layers are eroded and corestone are exposed. The soil-rock interface failure shows the most fast initial erosion process among the failure types. Interestingly, the common feature observed from the different types of failure was the occurrence of the initial deformation near the toe of slopes which implies the existence of surbsurface flow along the downslope direction.

• Journal of the Korea Convergence Society
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• v.13 no.1
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• pp.269-282
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• 2022

The purpose of this study is not only to explore the effects of emotional labor on job stress but also to investigate the moderating effects of grit and social support between emotional labor and job stress. A survey was conducted for 804 call center counselors in Daegu, Daejeon and Suwon to figure out research questions, and the collected data were analyzed with SPSS 25.0. The results of the data analysis are as follows. First, emotional labor of customer counselors was found to have a positive effect on job stress. Second, in the relationship between emotional labor and job stress of customer counselors, grit showed different results according to sub-factors. The higher the Perseverance of Effort, the higher the job stress, and the higher the Consistency of Interest, the lower the job stress. Third, in the relationship between emotional labor and job stress of customer counselors, supervisor support of social support had a moderating effect, while peer support had no moderating effect. It shows that in order to prevent job stress of customer counselors, who have a high intensity of emotional labor, it is necessary to intervene to help them develop a positive perception of themselves through non-cognitive factors such as grit and the support provided by a trusted target. In addition, appropriate intervention methods and educational environment should be supported.