• Tuberculosis and Respiratory Diseases
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• v.84 no.2
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• pp.125-133
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• 2021

Background: The coronavirus disease (COVID-19) can manifest in a range of symptoms, including both asymptomatic systems which appear nearly non-existent to the patient, all the way to the development of acute respiratory distress syndrome (ARDS). Specifically, COVID-19-associated pneumonia develops into ARDS due to the rapid progression of hypoxia, and although arterial blood gas analysis can assist in halting this deterioration, the current environment provided by the COVID-19 pandemic, which has led to an overall lack of medical resources or equipment, has made it difficult to administer such tests in a widespread manner. As a result, this study was conducted in order to determine whether the levels of oxygen saturation (SpO₂) and the fraction of inhaled oxygen (FiO₂) (SF ratio) can also serve as predictors of ARDS and the patient's risk of mortality. Methods: This was a retrospective cohort study conducted from February 2020 to Mary 2020, with the study's subjects consisting of COVID-19 pneumonia patients who had reached a state of deterioration that required the use of oxygen therapy. Of the 100 COVID-19 pneumonia cases, we compared 59 pneumonia patients who required oxygen therapy, divided into ARDS and non-ARDS pneumonia patients who required oxygen, and then investigated the different factors which affected their mortality. Results: At the time of admission, the ratios of SpO₂, FiO₂, and SF for the ARDS group differed significantly from those of the non-ARDS pneumonia support group who required oxygen (p<0.001). With respect to the predicting of the occurrence of ARDS, the SF ratio on admission and the SF ratio at exacerbation had an area under the curve which measured to be around 85.7% and 88.8% (p<0.001). Multivariate Cox regression analysis identified that the SF ratio at exacerbation (hazard ratio [HR], 0.916; 95% confidence interval [CI], 0.846-0.991; p=0.029) and National Early Warning Score (NEWS) (HR, 1.277; 95% CI, 1.010-1.615; p=0.041) were significant predictors of mortality. Conclusion: The SF ratio on admission and the SF ratio at exacerbation were strong predictors of the occurrence of ARDS, and the SF ratio at exacerbation and NEWS held a significant effect on mortality.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.4
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• pp.57-64
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• 2022

Chloride, which is one of the main deterioration factors in reinforced concrete structures, can degrade the performance of the structure due to chloride-induced corrosion of steel. Chloride content at steel depth or the rate of chloride penetration is necessary to determine deterioration of reinforced concrete or to calculate initiation time of steel corrosion caused by chloride attack. Chlorides in concrete are generally identified with typical two methods including chloride profiling using potentiometric titration method and discoloration method using AgNO₃ solution. The former is advantageous to estimate chloride penetration rate (diffusion coefficient in general) with measured chloride contents directly, but it is laborious. In the case of latter, while the result is obtained easily with the range of discoloration, the error may occur depending on workmanship when the depth of chloride ingress is measured. This study shows that chloride penetrated depth is evaluated with the results obtained from discoloration method through image analysis, thereby the error is minimized by workmanship. In addition, the effect of micro-crack in concrete is studied on chloride penetration. In conclusion, the depth of chloride penetration was quantified with image analysis and as it was confirmed that chlorides can rapidly penetrate through micro-cracks, caution is especially required for cracks in concrete structure.

• Journal of Conservation Science
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• v.37 no.6
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• pp.778-790
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• 2021

The Stone Seated Buddha Triad and Stone Standing Buddha in Bijung-ri are state-designated heritage (treasure) statues having the Buddha style of the Goryeo dynasty from the 6th century. Conservation scientific investigations were conducted to understand the preservation status of these stone Buddha statues and to establish a conservation plan. The Stone Seated Buddha Triad and Stone Standing Buddha are composed of fine-medium grained biotite granite, which is considered to be of the same origin owing to their low magnetic susceptibility distribution of less than 0.2 (×10^-3 SI unit) and similar mineral characteristics. The Stone Seated Buddha Triad has highly homogenous mineral composition and particle size, whole-rock magnetic susceptibility, and geochemical characteristics very similar to those of the nearby outcrop. It was confirmed that a combination of physical, chemical, and biological factors affects the Stone Buddha statues. In particular, both the Stone Seated Buddha Triad and Stone Standing Buddha tend to be chipped off from the front and cracked and scaled from the back. The Stone Standing Buddha located outdoors experiences granularity decomposition and black algae formation, which accelerate the weathering under unfavorable conservation environments. The result of non-destructive physical property diagnosis using ultrasonic velocity showed that both the Stone Seated Buddha Triad and Stone Standing Buddha have been completely weathered (CW), indicating very poor physical properties.

• Economic and Environmental Geology
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• v.56 no.6
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• pp.675-695
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• 2023

The tracksite of dinosaurs and pterosaurs in Sanbuk-dong of Gunsan is the largest early Cretaceous dinosaur footprint fossil site in Korea, and all the footprints are important evidence indicating that large ornithopod and theropod dinosaurs inhabited the Korean peninsula during the early Cretaceous. The Sanbuk-dong site was covered with waterproof sheet in an outdoor environment until the installation of a protective enclosure in 2021. As a result, various factors such as shear force, load reduction, temperature and humidity fluctuations, acid rain, salinity and microorganisms have complexly interacted in the substrate of fossils, exacerbating the damage to footprints. For 159 footprints in 12 trackways among the footprints found in the site, the damage types were classified in detail and the level of each damage was assessed. The damages were classified into 6 types through the classification of deterioration degree of individual footprints. As a result of ultrasonic physical property evaluation on the surface of the fossil site, most of these footprints are in the completely weathered (CW) stage. Furthermore, various weathering patterns were observed in the study area, and surface contaminants were analyzed along the stratigraphy. Although the patterns of freshness and contaminants varied at different points within the fossil site, the chemical compositions were similar. Based on the results, an efficient conservation management system for dinosaur footprint fossils was established, and a conservation treatment type for each footprint was proposed.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.55-61
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• 2023

In this study, a basic research was conducted to establish a maintenance plan considering the environmental factors and deterioration characteristics of port facilities. The precise safety diagnosis reports for Incheon and Busan port facilities were referenced to examine the extent of deterioration and damage. The relationship with the degradation environmental assessment presented in the current guidelines was also analyzed. The analysis of the damage level of Incheon and Busan port facilities revealed that Incheon Port exhibited approximately three times higher damage rate compared to Busan Port. In the case of Incheon Port, reinforcement corrosion and external damage showed similar proportions, while in Busan Port, reinforcement corrosion had a higher proportion compared to external damage. On the other hand, when comparing with the degradation environmental assessment presented in the guidelines, it was found that there were some limitations in performing quantitative evaluation based on the guidelines for assessing port facilities. Therefore, an analysis based on tidal range was conducted by referring to existing literature. The analysis of tidal range in Incheon and Busan regions showed that Incheon had approximately five times higher difference compared to Busan. It is considered that this can be utilized as a differentiated item from existing degradation environmental assessment criteria.

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.100-107
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• 2024

Currently, in Korea, due to the rapid aging and deterioration of facilities, the minimum Maintenance Level and Performance Level' of facilities are required by the 'Facility Safety Act' or 'Infrastructure Management Act'. Since infrastructure assets have a long lifespan and the pattern of deterioration over time is complex, it is very difficult to maintain infrastructure as 'minimum maintenance state' or 'minimum performance state' by the current way of management. 'Asset Management' shall be performed not only by a technical perspective, but also by an accounting perspective such as cost and asset value. However, due to lack of awareness of 'asset management' among stakeholder, only technical perspective management is being carried out in practice. In order to effectively manage infrastructure assets, complex consideration of various asset value factors such as budget and service as well as safety and durability are required. In this paper, we presented a theory to evaluate and quantify the road network value for efficient asset management of the road network. We also presented a method of simulation to apply the theory presented in this paper. Through simulation and the results derived from this study, it is possible to specify the budget for the future national asset management, and to optimize the strategy for the management of old road facilities.

• Childhood Kidney Diseases
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• v.11 no.2
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• pp.239-246
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• 2007

Purpose : The progressive deterioration of renal function in children can impose a serious and lifelong impact on their lives. The ultimate goal in the management of children with chronic kidney disease(CKD) is to prolong survival, to prevent complications, and to promote growth and neurodevelopment. The aim of this study is to investigate the risk factors for the decline of renal function in pediatric CKD patients. Methods : Data from patients who met the criteria for the Kidney Disease Outcomes Quality Initiative(K/DOQI) CKD stage 2 to 4 between August 1999 and March 2007 were retrospectively analyzed. The estimated glomerular filtration rate(eGFR) was calculated by the Schwartz formula, using serum creatinine levels and height. We calculated the annual eGFR change from the difference between the baseline eGFR and the last eGFR divided by the duration(years) of the follow-up period. We analyzed the association between the annual eGFR change and factors such as age, gender, K/DOQI stage, underlying renal disease, serum calcium, and inorganic phosphorous during the follow-up period. Results : Sixty one children(44 boys & 17 girls) were enrolled. The age at entry was $7.1{\pm}4.7$ years. The annual eGFR change was $-1.2{\pm}11.9 mL/min/1.73m^2/year$. Our study showed that older age(P=0.005). hypocalcemia(P=0.012), and hypenhosphatemia(P=0.002) were significantly related to more rapid decline in renal function. Conclusion : In pediatric CKD, older age, hypocalcemia and hyperphosphatemia are related to more rapid deterioration of renal function.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.10
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• pp.4543-4550
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• 2012

The purpose of this paper is to suggest the improvement method to achieve the interactive development effect between high-tech industrial complex and its surrounding areas. For this reason, this paper has conducted an empirical analysis to find out relevant comprehensive factors, affecting nearby housing prices from such plans, especially by reviewing 'Seoul Digital Industrial Complex.' This paper is truly differentiated from previous research by adding a new perspective 'diverse location characteristics', as it focuses not only on 'high-tech facility' characteristics, but also on 'urban function facilities', including 'transportation facilities', 'amenity facilities', 'security facilities', etc. Then, SPSS Version 18.0 was utilized to conduct the multiple regression analysis with the accumulated relevant data and several results were drawn out as following: Firstly, 'deterioration level', 'brand of apartment', etc. are found to be major influencing factors. Secondly, 'educational facilities', 'transportation facilities', 'Cultural & Sports facilities', 'Amenity facilities', etc. are found in the sector of 'location characteristic'. Lastly, 'leading companies within the industrial complex', were also found, affecting nearby housing prices. Therefore, when a housing development project is planned to grant the interactive development effect to high-tech industrial complex and its surrounding housing areas, it is necessary to consider variety factors, such as comprehensive location characteristics and housing complex characteristics, and also proper housing policy measures should be devised in accordance with the actual demand of employees and their dependant family members.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.11
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• pp.297-307
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• 2017

There are many underground spaces available in an urban environment and they represent an important factor for efficient land use. Especially, underground shopping centers perform both physical and commercial functions at the same time and are frequently used as a means of achieving the revitalization of the city center. However, the underground shopping centers that were developed in the past sometimes led to recession due to their deterioration. This study was carried out for the purpose of proposing alternative methods for the (revitalization) of underground shopping centers. A survey was conducted on seven underground shopping centers in the Busan metropolitan area to understand the factors that determine their user satisfaction and future improvement. The survey data was analyzed using an ordered logit model. As a result of the analysis, service satisfaction, underground environment satisfaction and public facility satisfaction were selected as significant variables. It was concluded that it is necessary to take these factors into consideration, appropriately, when developing a new or renewing an existing underground shopping mall.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.111-120
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• 2020

This study examined the factors affecting the readmission of patients with liver cirrhosis, and focused on self-care, social support, and drinking refusal self-efficacy. The subjects were 75 cirrhosis patients who were admitted to medium-sized hospitals at S-city for two months from May 2019 to June 2019. The data was analyzed with the SPSS (Version 25) program, and logistic regression analysis was performed on the factors affecting readmission. The results were self-care (27.49±0.53 out of 60), social support (52.80±16.44 out of 90), and drinking refusal self-efficacy (42.39±22.76 out of 80). The readmission method was classified into planned and unplanned admissions. Unplanned readmission was found to differ depending on the drinking experience (OR: 4.16) and the presence of complications (OR: 5.11) within a month of discharge rather than that of the planned readmissions, accounted for 19.7%. It will be very important to reduce the occurrence of complications by early management of patients with cirrhosis, and increase the drinking refusal self-efficacy, and so reduce unplanned readmission and prevent the progression and deterioration of cirrhosis. The drinking experience and the occurrence of complications can be reduced through interventions that increase self-care, social support, and drinking refusal self-efficacy. Nursing interventions are needed to prevent patients with cirrhosis from drinking and to manage the complications due to relapse into alcoholism.