• Computers and Concrete
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• v.19 no.1
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• pp.111-120
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• 2017

This study aimed to design the accelerated life testing (ALT) of concrete, which stimulating the special natural environment maximumly. Its evaluation indexes, such as dynamic elastic modulus, mass and ultrasonic velocity were measured, and the variation of relative mass and relative dynamic elastic modulus of concrete were studied. Meanwhile, the microanalysis method was used. Moreover, an exploratory application of the stochastic approach, the Weibull distribution and the lognormal distribution, were made to assess the durability of concrete structures. The results show that the ALT for simulating natural environment is more close to the service process of concrete structure under actual conditions; The relative dynamic elastic modulus can be used as the dominant durability evaluation parameters, because it is more sensitive to the environmental factors compared with the relative quality evaluation parameters; In the course of the concrete deterioration, the destruction of the salt freezing cycle is the dominant factor, supplemented by other factors; Both of those two stochastic approaches can be used to evaluate the reliability of concrete specimens under the condition of ALT; By comparison, The lognormal distribution method is better to describe the reliability process.

• Journal of the Korean Institute of Educational Facilities
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• v.23 no.6
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• pp.27-34
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• 2016

Although the scale and number of university facilities have increased, the maintenance of these facilities has not been efficient as maintenance costs incurred during facility operation periods, as well as management time, have not been sufficiently considered. In this study, the maintenance record data of national universities was compared and analyzed to analyze factors that incur maintenance costs according to the uses and costs of the facilities. According to the results, the number of cases of maintenance and repair work for basic educational facilities was shown to be the largest, accounting for 79%. The number of maintenance and repair work occurred according to work type was examined. According to the results, the highest ratio of maintenance and repair work occurred in the field of construction, specifically, the maintenance costs required for facility supplementation accounted for the highest ratio. Maintenance costs per unit area decreased over time in the newer university facilities, while showing a tendency to increase in older university facilities. However, there were cases where maintenance costs did not show any trends due to factors such as the limited maintenance budgets owing to the characteristics of public service facilities and facilities in the stage of deterioration or destruction after the stage of stabilization. This study is considered to be helpful for efficient university facility maintenance plans and budget calculations.

• Journal of Welding and Joining
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• v.5 no.4
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• pp.22-27
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• 1987

The debonding of clad steel was often occurred at interface between stainless steel and carbon steel during the fabrication of pressure vessel. In order to clarify the causes of debonding phenomena, the fabrication sequences were fully analyzed. As a result, possible factors were noticed for causing the debonding of clad steel, that is, thermal treatment on weldment and welding. Moreover the existence of hydrogen diffused from surroundings also expedites the debonding of clad steel. In this stud, the effect of welding thermal cycle, hydrogen and mixed condition under thermal treatment on the interfacial strength of clad steel were investigated to understand the debonding mechanism of clad steel. From this study, it has been confirmed that the interfacial strength of clad steel was remarkablely deteriorated due to welding and/or existence of hydrogen under thermal treatment. In the case of welding thermal cycle effect, the higher temperature at interface experienced by welding, the more reduction in interfacial strength of clad steel resulted in. And the existence of diffusible hydrogen also reduced the interfacial strength. It is also found that the interfacial strength of clad steel became much lower value than that of the as-received plate under coexistence of above mentioned factors.

• Food Science of Animal Resources
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• v.37 no.6
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• pp.873-883
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• 2017

Variations in the definition of poultry meat quality exist because the quality traits are not solely based on intrinsic and extrinsic factors but also consumers' preference. Appearance quality traits (AQT), eating quality traits (EQT), and reliance quality traits (RQT) are the major factors focused by the consumer before buying good quality of poultry meat. AQT and EQT of poultry meat are controlled by physical and biochemical characteristics of muscle fibers which can be categorized into a total number of fibers (TNF), cross-sectional area of fibers (CSAF), and fiber type composition (FTC). In poultry meat, it has been shown that muscle fiber properties play a key role in meat quality because numerous studies have reported the relationships between quality traits and fiber characteristics. Despite intensive research has been carried out to manipulate the muscle fiber to improve poultry meat quality, demand in a rapid growth of poultry muscle has correlated to the deterioration in the meat quality. The present paper reviews the definition of poultry meat quality, meat quality traits, and variations of meat quality. Also, this review presents recent knowledge underlying the relationship between poultry meat quality traits and muscle fiber characteristics.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.141-152
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• 2011

In this study, we extracted effective factors of pipe burst from the status data of water asset, operating data of pressure, volume and etc. and 7 years' pipe burst and repair records. The extracted factors were sorted by each attribution and then a statistical analysis was performed to generate a pipe burst probability function using the logistic regression model. As the result, material, diameter, length, laying year, pressure and road width affected to pipe burst significantly. Especially, in case of small diameter, laying year was most effective factor and in case of steel pipe, external loading was main cause of burst, and in case of cast iron, PE, PC, HP pipes, the deterioration of joint was main cause. The other side, as a result of Hosmer-Lemeshow goodness of fit test the models are turned out significant statistically. Also the classification criteria were determined to minimize the total cost from classification errors, when the predicted probability was more than 18% this pipe could have a chance of burst.

• KIEAE Journal
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• v.14 no.5
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• pp.123-130
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• 2014

In order for effective heat island reduction policies to be proposed, this research made use of the land usage and land coverage and Temperature of cities, Coordinate axis data within 500 meters of nationwide automatic weather stations (478 points) in order to analyze the correlation of summertime temperatures through multiple regression analysis. This research also developed a model and empirically analyzed the urban heat island reduction effect of factors that affect regional temperatures. Heat islands cause environment deterioration and therefore can harm citizens' health, and also affects the city's metabolism process. Thus in order to restrain regional temperature rises the conclusion was drawn that consideration to increase forest areas on part of land usage planning is needed. Appropriate policy measures to regulate traffic related factors are also needed to restrain regional temperature rises. In order for future heat island reduction this research proposes a way to set up more effective policies and urban sustainability improvement strategies, and is significant in that it makes use of detailed data such as land usage and land coverage, Temperature of cities, Coordinate axis in analyses.

• Child Health Nursing Research
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• v.28 no.2
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• pp.142-153
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• 2022

Purpose: Preventing missed care is important in neonatal intensive care units (NICUs) due to neonates' vulnerabilities. This study examined missed care and its influencing factors among NICU nurses. Methods: Missed care among 120 Korean NICU nurses was measured using a cross-culturally adapted online questionnaire. The frequency of missed care for 32 nursing activities and the significance of 23 reasons for missed care were collected. Results: All participants had missed at least 1 activity, missing on average 19.35 activities during a typical work-day. The most common missed item was "provide developmental care for the baby". The most common reason for missed care was "emergency within the unit or deterioration of one of the assigned patients". The final regression model explained 9.6% of variance in missed care. The average daily number of assigned patients receiving inotropes or sedation over the last month influenced the total number of missed care items. Conclusion: Missed care was affected by nurses' workload related to the number of patients taking medication. Frequently missed activities, especially those related to developmental care, require patience and time, conflicting with safety prioritization and inadequate working conditions. NICU nurses' working conditions should be improved to ensure adequate time for nursing activities.

• Tuberculosis and Respiratory Diseases
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• v.85 no.2
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• pp.122-136
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• 2022

Although chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD) have distinct clinical features, both diseases may coexist in a patient because they share similar risk factors such as smoking, male sex, and old age. Patients with both emphysema in upper lung fields and diffuse ILD are diagnosed with combined pulmonary fibrosis and emphysema (CPFE), which causes substantial clinical deterioration. Patients with CPFE have higher mortality compared with patients who have COPD alone, but results have been inconclusive compared with patients who have idiopathic pulmonary fibrosis (IPF). Poor prognostic factors for CPFE include exacerbation, lung cancer, and pulmonary hypertension. The presence of interstitial lung abnormalities, which may be an early or mild form of ILD, is notable among patients with COPD, and is associated with poor prognosis. Various theories have been proposed regarding the pathophysiology of CPFE. Biomarker analyses have implied that this pathophysiology may be more closely associated with IPF development, rather than COPD or emphysema. Patients with CPFE should be advised to quit smoking and undergo routine lung function tests, and pulmonary rehabilitation may be helpful. Various pharmacologic agents and surgical approaches may be beneficial in patients with CPFE, but further studies are needed.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.6_3
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• pp.1303-1313
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• 2022

Modern cities need to revitalize the downtown area, which is declining due to population decline, economic recession, and deterioration of the residential environment, economically, socially, and physically by introducing and creating new functions. In addition, the hollowing out of the existing city center is getting worse due to the development of the outskirts of the city. Therefore, the discussion for the development of urban regeneration is the core task of modern cities. This study analyzed based on a basic understanding of urban regeneration projects, and through this, the problems of domestic urban regeneration projects were derived. In addition, the problem factors and major improvement plans of the urban regeneration project were analyzed from the expert's point of view using the AHP analysis technique. Based on this, the purpose is to present policy alternatives for the future development of urban regeneration projects. The problems derived to present the policy alternatives and improvement directions of the urban regeneration project were classified into problems related to goal achievement, problems related to the business itself, and problems related to project results. It was subdivided into sub-categories. This study analyzed the problem factors and major improvements from the expert's point of view by using the AHP analysis technique for the problems of the urban regeneration project. Based on the AHP analysis results and experts' opinions, five policy alternatives for the development of urban regeneration projects were presented.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.59 no.3
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• pp.271-278
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• 2023

This study aims to analyze the income structure, cost structure, and profit structure based on data related to the business performance of the boat seine fishery from 1990 to 2020, and to identify the direct and indirect factors affecting fishery profitability through panel regression analysis. The main analysis results are as follows. First, it was found that fish catch has a significant amount of impact on fishery profitability, which is a key factor in improving the profitability of anchovy boat seine fishery. Second, it is necessary to develop carbon-reduced fishing gear, develop fleet-reduced fishing gear, and improve the operating system in order to increase fishery profitability for the short run. Third, it is necessary to create and maintain sustainable profitability for the long run, the continuous fishing vessels buyback program, an active responses to climate change, and the follow-up investigations about marine aggregate extraction in the south sea EEZ are needed.