• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.4
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• pp.28-36
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• 2021

It is known that buried rebars inside concrete structures are protected from corrosion due to passive layer. It is very important to delay the timing of corrosion or evaluate a detection of corrosion initiation for the purpose of cost-beneficiary service life of a structure. In this study, corrosion monitoring was performed on concrete specimens considering 3 levels of cover depth(60 mm, 45 mm, and 30 mm), W/C(water to cement) ratio(40.0%, 50.0%, and 60.0%) and chloride concentration(0.0%, 3.5%, and 7.0%). OCP(Open Circuit Potential) was measured using agar-based socket type sensors. The OCP measurement showed the consistent behavior where the potential was reduced in wet conditions and it was partially recovered in dry conditions. In the case of 30 mm of cover depth for most W/C ratio cases, the lowest OCP value was measured and rapid OCP recovery was evaluated in increasing cover depth from 30 mm to 45 mm, since cover depth was an effective protection against chloride ion ingress. As the chloride concentration increased, the effect on the cover depth tended to be more dominant than the that of W/C ratio. After additional monitoring and physical evaluation of chloride concentration after specimen dismantling, the proposed system can be improved with increasing reliability of the corrosion monitoring.

• Journal of Wetlands Research
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• v.21 no.1
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• pp.77-83
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• 2019

Stream water qualities have been predicted in the year 2002 and 2014 through providing the Hwangguji Stream Rectification Plan. However, the reliability of result for predicted water quality was relatively lower by applying conventional values of the parameters in model. In this study deoxygenation coefficients between Sema bridge(HGJ2) and Sujik bridge(HGJ3) have been evaluated based on the observed data of water quality and travelling time to compare with the applied value of coefficients in predicting water quality model. The values of deoxygenation coefficient $0.078day^{-1}{\sim}0.748day^{-1}$ for normal period and $0.053day^{-1}{\sim}0.505day^{-1}$ for drought period have been calculated based of observed data between Sema bridge and Sujik bridge. The values of coefficients $0.02day^{-1}{\sim}3.4day^{-1}$ have been applied in predicting water quality model in the year 2002 and $0.043day^{-1}$ 2014. Thus, the simulated results of stream water quality were better than the observed data in 2002, and worse in 2014. It has shown that values of deoxygenation coefficient should be properly estimated based on observed data to predict proper stream water quality by model.

• The Korean Journal of Archival Studies
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• no.15
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• pp.219-262
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• 2007

Business organization have developed in close association with the society afterward. Moreover, under capitalism business archives, though they are created in private sector, have started to have public characteristics and be used in public domain beyond internal use in business organization. Records and Archives management at a corporate level increasingly become indispensible. Business organization can use archive management to improve job efficiency and customer service and to facilitate legal matters, marketing, advertising, property management, personnel management and publicity. Additionally, They can secure corporate identity and social reliability as well as transparency in management. This is turn helps secure corporate competitiveness to play as a medium for creating new profit, which will enhance corporate brands. The records and Archives management, which recently kicks off among business organization, are to collect scattered archives and seek systemic management through archives management systems. This study present ways to collect archives scattered before archives management systems were adopted according to archives management. As a prior investigation, the scope and characteristics of business archives are defined. Visit to business organization to collect data and interview with officials responsible were carried out as a preliminary investigation to conduce acquisition policy. Based on the results of the investigation, acquisition policy of Meritz was conducted. into internal and external collection activities, event collection activities. Value appraisal and display appraisal of archives were established as a appraisal policy for efficient management and utilization of collected business archives. This study takes the case of Metitz Fire & Marine Insurance Co, Ltd (Meritz) as a example to present ways to manage business archives specifically.

• Journal of Science Education
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• v.42 no.3
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• pp.334-351
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• 2018

Teacher's gaze empathy for students in science class is considered to be effective in enhancing the learning effect. Thus, studies on gaze empathy have been conducted, but most of the studies are just to reveal the characteristics of gaze. Therefore, it is necessary to deal with a research to raise the level of science teacher's gaze empathy. The purpose of this study is to develop an instruction consulting strategy based on eye tracking for improving science teachers' gaze empathy. In this study, we selected and analyzed relevant literature on teacher's gaze empathy. We also designed a consulting strategy and then revised the design through expert reviews on validity and reliability. The developed consulting strategy was aimed to improve science teacher's gaze empathy and set quantitative goal based on eye tracking. The consulting strategy consisted of six steps: preparation for consulting, measurement and analysis of teacher's gaze empathy, instruction and feedback of gaze empathy, training for improving gaze empathy, evaluation of consulting result, and completion of the consulting. In addition, the consultation was completed or repeated again through the measurement and evaluation of gaze empathy using eye tracking. The developed consulting strategy has a value in that it provides an alternative with quantitative diagnosis and prescription for improving gaze empathy. The strategy can contribute to enhance teacher professional competency through the analysis of teaching behavior.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.5
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• pp.609-616
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• 2019

When the fouling of a vessel occurs, its resistance at sea increases and there is a corresponding increase in fuel consumption. The maintenance cost of the vessel also increases because it is time-consuming to remove the fouling. To solve this problem and minimize environmental contamination of sea-water, there have been recent developments in anti-fouling paints as self-polishing copolymers that not include toxic elements such as tin. When these conventional techniques are applied to vessels, polishing is promoted during the operation whereby friction or vibration with seawater occurs. This leads to enhanced anti-fouling performance. However, when fouling is intensified such as during an anchorage, there is no flow of seawater and polishing is suppressed. This leads to a deterioration of the performance of anti-fouling. To solve these problems, we developed a system that induces vibration in a vessel during anchorage. As such, the deterioration of polishing due to insuf icient flow of seawater is inhibited. The reliability of the ultrasonic antifouling system was evaluated by calculating its repeatability. The removal efficiency of fouling of the proposed system was qualitatively evaluated using test specimens. The test revealed that the value of the coefficient of variation for the reproducibility of the frequency and amplitude was 0.2 % and 4.0 % on average. The degree of fouling of the specimens was the highest at 73.3 g in the No.5 sepcimen. Moreover, efficiency of fouling removal was 93.2 % on average compared to the specimens without the proposed system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.9
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• pp.474-480
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• 2019

We propose a method to evaluate a Modulation Transfer Function (MTF) using a circular target. In addition, a MATLAB GUI-based resolution analysis tool was developed to enhance the reliability of UAV image quality and the efficiency of the work. For this purpose, images were taken with an FC-6310 during flights at altitudes of 80 m, 120 m, and 150 m and by an iXM-100 at altitudes of 150 m, 200 m, and 400 m. The MTFs of UAV images were compared with traditional photogrammetry by measuring and analyzing MTFs on images taken by the UltraCAM Eagle Mark-2 sensor at a flight altitude of 1000 m. The results show that ${\sigma}MTF$ of the FC-6310 were 0.431(80 m), 0.524(120 m), and 0.699(150 m), and those of the iXM-100 were 0.332(150 m), 0.393(200 m), and 0.631(400 m), respectively. At the altitude of 150 m, the image quality of the iXM-100, which has a high-performance camera, was very high, and the effect of the camera performance on the image quality was confirmed. In addition, the ${\sigma}MTF$ of the UltraCAM Eagle Mark-2 was 0.711 due to the high flight altitude. This was the worst value among all UAV images. However, the ${\sigma}MTF$ of the FC-6310 at 150-m altitude was 0.699, which is almost the same as that of a manned aerial image.

• 한국체육학회지인문사회과학편
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• v.56 no.6
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• pp.607-618
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• 2017

The purpose of the study was to examine the mediating effect of attribution style on relationship between students' community sense and school adjustment in middle school on inclusive physical education. For this, the study conducted survey targeting 380 students without disabilities from B city who were participating in middle school on inclusive physical education among them were surveyed through convenience sampling were used for final data processing. To analyze the data to verify the hypotheses, SPSS 21.0 program population sociological characteristics were used for frequency analysis, confirmatory factor analysis was used to test the validity of the collected data, and correlation analysis, and Cronbachs'${\alpha}$ value was used for reliability test. And AMOS 20.0 program were utilized to conduct mediating analysis and the statistically significant level (p) is fixed as .05. The results are the following. First, there was a statistically significant correlation between non-disabled student's sense of community, school adjustment and internal attribution. Second, internal attribution partially mediated the relationship between the sense of community of non-disabled students and school adjustment. However external attribution did not mediate the relationship between sense of community of non-disabled students and school adjustment.

• Journal of Platform Technology
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• v.9 no.3
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• pp.52-62
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• 2021

Quality control is critical at manufacturing sites and is key to predicting the risk of quality defect before manufacturing. However, the reliability of manual quality control methods is affected by human and physical limitations because manufacturing processes vary across industries. These limitations become particularly obvious in domain areas with numerous manufacturing processes, such as the manufacture of major nuclear equipment. This study proposed a novel method for predicting the risk of quality defects by using natural language processing and machine learning. In this study, production data collected over 6 years at a factory that manufactures main equipment that is installed in nuclear power plants were used. In the preprocessing stage of text data, a mapping method was applied to the word dictionary so that domain knowledge could be appropriately reflected, and a hybrid algorithm, which combined n-gram, Term Frequency-Inverse Document Frequency, and Singular Value Decomposition, was constructed for sentence vectorization. Next, in the experiment to classify the risky processes resulting in poor quality, k-fold cross-validation was applied to categorize cases from Unigram to cumulative Trigram. Furthermore, for achieving objective experimental results, Naive Bayes and Support Vector Machine were used as classification algorithms and the maximum accuracy and F1-score of 0.7685 and 0.8641, respectively, were achieved. Thus, the proposed method is effective. The performance of the proposed method were compared and with votes of field engineers, and the results revealed that the proposed method outperformed field engineers. Thus, the method can be implemented for quality control at manufacturing sites.

• The Journal of the Korea Contents Association
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• v.21 no.2
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• pp.437-444
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• 2021

The aim of this study was to compare the cardiac CT and cardiac MRI in calculating and correcting the left ventricle ejection fraction by analyzing the physical and temporal resolution for reducing the misdiagnosis rate. One hundred thirty-eight patients with aortic value regurgitation who underwent both cardiac CT and cardiac MRI were analyzed. Left ventricle ejection fractions calculated from each exam were corrected based on the physical and temporal resolution differences and the reliability test evaluated whether the misdiagnosis rate of cardiac CT was improved after the correction. As a result of the study, the misdiagnosis rate of cardiac CT ejection fraction before correcting the difference in physical and temporal resolution was 38.4%(53 persons). In addition, it can be seen that the corrected cardiac CT ejection fraction confirmed in the Bland-Altman plot was highly consistent with the ejection fraction of cardiac MRI. In conclusion, as the cardiac CT is less well suited for measuring ejection fraction, physical characteristics and the time resolution correction using cardiac MRI is needed and the misdiagnosis rate after correction decreased to 14.5%(20 persons). Therefore, this study appears more appropriate for better prediction of ejection fraction and clinical utility.

• Journal of Environmental Health Sciences
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• v.47 no.1
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• pp.64-77
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• 2021

Objective: Biological monitoring of trace elements in human blood samples has become an important indicator of the health environment. The purpose of this study was to detect and evaluate multiple metal items in blood samples based on ICP-MS, to perform comparative evaluation with the existing analysis method, and to develop and verify a new method. Methods: 100 μL of whole blood from 80 healthy subjects was used to analyze ten metals (Sb, tAs, Cd, Pb, Mn, Hg, Mo, Ni, Se, Tl) using ICP-MS. Verification of the analysis method included calculation of linearity, accuracy, precision and detection limits. In addition, a comparative test with the conventional graphite furnace atomic absorption spectroscopy (GF-AAS) method was performed. In the case of Pb, Cd, and Hg in whole blood, cross-analysis between Pb, Cd, and Hg analysis methods was performed to confirm the difference between the existing method and the new method (ICP-MS). Results: The coefficient of determination (R2) was 0.999 or higher in seven items and 0.995 or higher in three items. The Pb result showed that Pearson's correlation coefficient was very high at 0.983, and the intraclass correlation coefficient was 0.966. The Cd result showed that Pearson's correlation coefficient was 0.917 between the existing method and the new analysis concentration value. Its intraclass correlation coefficient was 0.960, and there was no significant difference between the two groups. Hg had a low correlation at 0.687, and the intraclass correlation coefficient was 0.761, which was lower than that of Pb and Cd. The intra-day and inter-day accuracy of Pd and Cd were satisfactory, but Hg did not meet the criteria for both accuracy and precision when compared with the conventional analysis method. Conclusion: This study can be meaningful in that it proposes a more efficient and feasible analysis method by verifying a blood heavy metal concentration experiment using multiple simultaneous analyses. All samples were processed and analyzed using the new ICP-MS. It was confirmed that the agreement between the two methods was very high, with the agreement between the current and new methods being 0.769 to 0.998. This study proposes an efficient simultaneous methodology capable of analyzing multiple elements with small samples. In the future, studies of various applications and the reliability of ICP-MS analysis methods are required, and research on the verification of accurate, precise, and continuous analysis methods is required.