• Design & Manufacturing
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• v.17 no.1
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• pp.40-47
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• 2023

Macular degeneration and glaucoma are representative age-related retinal diseases that rank second and third in the prevalence of retinal diseases, and are a kind of degenerative neurological disease. Irreversible visual acuity and visual field damage may occur, and the number of patients is rapidly increasing as the population ages. Since this retinal disease is a chronic disease, continuous drug treatment is required. There are various drug delivery methods for treatment, but direct injection of the drug into the intravitreal is the most effective for continuous delivery of the drug over a long period of time. In order to solidify Dexamethasone, a retinal disease treatment, and insert it into the primary intravitreal, it is important to develop a technology to miniaturize the treatment and an applicator to deliver the treatment. In this study, a mold technology was developed to integrate the cannula and hub, which are one part of applicator. In addition, surface treatment was performed on the outside of the cannula to improve the bonding strength between the cannula and the hub, and the bonding strength according to each condition was analyzed through a tensile test.

• Nuclear Engineering and Technology
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• v.55 no.6
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• pp.2034-2046
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• 2023

Industrial control systems in nuclear facilities are facing increasing cyber threats due to the widespread use of information and communication equipment. To implement cyber security programs effectively through the RG 5.71, it is necessary to quantitatively assess cyber risks. However, this can be challenging due to limited historical data on threats and customized Critical Digital Assets (CDAs) in nuclear facilities. Previous works have focused on identifying data flows, the assets where the data is stored and processed, which means that the methods are heavily biased towards information security concerns. Additionally, in nuclear facilities, cyber threats need to be analyzed from a safety perspective. In this study, we use the system theoretic process analysis to identify system-level threat scenarios that could violate safety constraints. Instead of quantifying the likelihood of exploiting vulnerabilities, we quantify Security Control Measures (SCMs) against the identified threat scenarios. We classify the system and CDAs into four consequence-based classes, as presented in NEI 13-10, to analyze the adversary impact on CDAs. This allows for the ranking of identified threat scenarios according to the quantified SCMs. The proposed framework enables stakeholders to more effectively and accurately rank cyber risks, as well as establish security and response strategies.

• Geomechanics and Engineering
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• v.37 no.4
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• pp.395-418
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• 2024

The epicentral region of earthquakes is typically where liquefaction-related damage takes place. To determine the maximum distance, such as maximum epicentral distance (R_e), maximum fault distance (R_f), or maximum hypocentral distance (R_h), at which an earthquake can inflict damage, given its magnitude, this study, using a recently updated global liquefaction database, multiple ML models are built to predict the limiting distances (R_e, R_f, or R_h) required for an earthquake of a given magnitude to cause damage. Four machine learning models LSTM (Long Short-Term Memory), BiLSTM (Bidirectional Long Short-Term Memory), CNN (Convolutional Neural Network), and XGB (Extreme Gradient Boosting) are developed using the Python programming language. All four proposed ML models performed better than empirical models for limiting distance assessment. Among these models, the XGB model outperformed all the models. In order to determine how well the suggested models can predict limiting distances, a number of statistical parameters have been studied. To compare the accuracy of the proposed models, rank analysis, error matrix, and Taylor diagram have been developed. The ML models proposed in this paper are more robust than other current models and may be used to assess the minimal energy of a liquefaction disaster caused by an earthquake or to estimate the maximum distance of a liquefied site provided an earthquake in rapid disaster mapping.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.4_2
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• pp.841-850
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• 2024

This study is about improving the welfare of firefighters, which has not been conducted in depth in previous studies. The overall level of welfare for firefighters was found to be 2.87 points on average (out of 5). Among the welfare status items, the most common answer was, 'Many firefighters may have post-traumatic stress disorder, even though they have not been diagnosed by a hospital.' The higher the rank and length of service, the higher the welfare status, and a statistically significant difference was confirmed (p(.01). In this study, the survey subjects were limited to some firefighters. We believe that these samples have limitations in generalizing the results of the study. However, the study is considered to be fruitful in that it identified the welfare status of some firefighters and confirmed their needs. I hope that the overall welfare of firefighters will be improved through periodic follow-up studies in the future.

• Asia-Pacific Journal of Business
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• v.15 no.3
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• pp.449-468
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• 2024

Purpose - The purpose of this study was to analyze the civil servant pension system in Korea, focusing on general administrative officials. Design/methodology/approach - This study developed a pension projection model that reflects the latest reforms and applied it to forecast the income replacement ratio and benefit ratios. Based on these projections, the study examined financial trends and proposed necessary reforms to ensure sustainability, such as adjusting the pension age. Findings - First, the benefit ratio decreases with later birth cohorts, showing that the reforms have reduced benefit gaps across generations. Second, while fairness within the same generation shows little difference between ranks, differences in income levels still result in significant disparities in pension amounts. Lastly, the pension deficit is expected to increase until 2029, after which it will gradually decrease, though further reforms are needed to ensure long-term financial sustainability. Research implications or Originality - This study is the first to comprehensively assess the fairness and sustainability of the civil servant pension system in Korea, considering both inter- and intra-generational equity. The findings provide valuable insights for policymakers aiming to ensure the system's sustainability as well as maintaining fairness across different cohorts and income levels.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.5
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• pp.1839-1843
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• 2015

Background: MicroRNAs are a class of noncoding RNAs which regulate multiple cellular processes during tumor development. The purpose of this report is to investigate the clinicopathological and prognostic significance of miR-218 in human gliomas. Materials and Methods: Quantitative RT-PCR (qRT-PCR) was conducted to detect the expression of miR-218 in primary normal human astrocytes, three glioma cell lines and 98 paired glioma and adjacent normal brain tissues.Associations of miR-218 with clinicopathological variables of glioma patients were statistically analyzed. Finally, a survival analysis was performed using the Kaplan-Meier method and Cox's proportional hazards model. Results: The expression level of miR-218 in primary normal human astrocytes was significantly higher than that in glioma cell lines (p<0.01). Also, the expression level of miR-218 in glioma tissues was significantly downregulated in comparison with that in the adjacent normal brain tissues (p<0.001). Statistical analyses demonstrated that low miR-218 expression was closely associated with advanced WHO grade (p=0.002) and low Karnofsky performance score (p=0.010) of glioma patients. Kaplan-Meier analysis with the log-rank test showed that patients with low-miR-218 expression had poorer disease-free survival and overall survival (p=0.0045 and 0.0124, respectively). Multivariate analysis revealed that miR-218 expression was independently associated with the disease-free survival (p=0.009) and overall survival (p=0.004) of glioma patients. Conclusions: Our results indicate that miR-218 is downregulated in gliomas and that its status might be a potential valuable biomarker for glioma patients.

• Journal of the Korean Institute of Landscape Architecture
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• v.37 no.4
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• pp.12-21
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• 2009

The purpose of this study is to identify the characteristics of amenities available in Sunchang-gun, Jeonbuk province in Korea through ananalysis of survey data of rural amenity resources. This survey was performed over 4 years(from 2005 to 2008). The data were collected by field survey, interview, and Internet search. Descriptive statistics, regression and correlation analyses were performed to identify the characteristics of each Eup-Myun in Sunchang County. A regression analysis was also performed to compare provincial, national and other county data. Furthermore, a rank analysis was performed to classify the type of each region. Through this, the type of rural amenity resources was identified.

• Journal of the Korea Convergence Society
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• v.9 no.4
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• pp.65-74
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• 2018

This study aimed to analyze convergently the result of the health check-up of the military workers at age of 40, a life transition period in Korea. Data of 4898 military workers who took a health check-up in 2015 was obtained from the national health insurance service and we conducted secondary analysis. As a results, the metabolic syndrome group had a greater current smoking rate, higher number of cigarettes smoked per day, longer period of smoking and higher amount of alcohol consumed. Also, the group scored higher on BMI and had a higher level of total cholesterol, AST, ALT and GGT. In conclusion, as the military workers at age of 40 usually perform important duties, effective programs of reducing smoking and drinking alcohol are needed for their age group, In order to develop health management programs, prior investigation to take into consideration specific age and military rank is necessary.

• Journal of Gastric Cancer
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• v.18 no.3
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• pp.242-252
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• 2018

Purpose: Surgical resection for gastric adenocarcinoma is associated with significant post-operative morbidity and mortality. The aim of this study was to assess the prognostic significance of sarcopenia in patients undergoing resection for gastric adenocarcinoma with respect to post-operative morbidity and survival. Materials and Methods: A retrospective analysis was conducted on a cohort of consecutive patients who underwent surgical resection for gastric adenocarcinoma between 2008 and 2014. Patient demographics, radiological parameters, and pathological data were collected. OsiriX software (Pixmeo) was used to measure skeletal muscle area, which was normalized for height to calculate skeletal muscle index. Results: A total of 56 patients (41 male, 15 female; mean age, $68.4{\pm}11.9years$) met the inclusion criteria. Of these, 36% (20 of 56) of the patients were sarcopenic pre-operatively. Both sarcopenic and non-sarcopenic patient groups were equally matched with the exception of weight and body mass index (P=0.036 and 0.001, respectively). Sarcopenia was associated with a decreased overall survival (log-rank P=0.003) and was an adverse prognostic predictor of overall survival in multivariate analysis (hazard ratio, 10.915; P=0.001). Sarcopenia was a predictor of serious in-hospital complications in multivariate analysis (odds ratio, 3.508; P=0.042). Conclusions: In patients undergoing curative resection for gastric cancer, there was a statistically significant association between sarcopenia and both decreased overall survival and serious post-operative complications. The measurement and reporting of skeletal muscle index on pre-operative computed tomography should be considered.

• Journal of Korean Society of societal Security
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• v.1 no.2
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• pp.53-59
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• 2008

The lack of water resources is becoming a serious issue throughout the world. The water shortage in Korea is expected to increase. Groundwater can be a solution to this matter in some places. Especially, bank filtrations are known to be advantageous over conventional reserviors, even if they have some drawbacks such as their limited location for development and small sizes. The AHP(Analytic Hierarchy Process) is an analytical tool, supported by simple mathematics, which enables one to explicitly rank tangible and intangible factors against each other for the purpose of resolving conflicts or setting priorities. In order to check the applicability of AHP to the evaluation of bank filtration sites, four candidate locations were chosen. They have suffered from problems like water-supply shortage and delayed dam construction. The analysis results are compared with those of the previous study using a conventional method. It is believed that the developed method can a basis for reasonable decision-making regarding bank filtration development.