• Smart Structures and Systems
• /
• v.19 no.3
• /
• pp.269-277
• /
• 2017

Recently, there has been significant interest in structural health monitoring for civil engineering applications. In this research, a specially designed tendon, proposed by embedding FBG sensors into the center king cable of a 7-wire strand tendon, was applied for long-term health monitoring of tensile forces on a ground anchor. To make temperature independent sensors, the effective temperature compensation of FBG sensors must be considered. The temperature sensitivity coefficient ${\beta}^{\prime}$ of the FBG sensors embedded tendon was successfully determined to be $2.0{\times}10^{-5}^{\circ}C^{-1}$ through calibrated tests in both a model rock body and a laboratory heat chamber. Furthermore, the obtained result for ${\beta}^{\prime}$ was formally verified through the ground temperature measurement test, expectedly. As a result, the ground temperature measured by a thermometer showed good agreement compared to that measured by the proposed FBG sensor, which was calibrated considering to the temperature sensitivity coefficient ${\beta}^{\prime}$. Finally, four prototype ground anchors including two tension ground anchors and two compression ground anchors made by replacing a tendon with the proposed smart tendon were installed into an actual slope at the Yeosu site. Tensile forces, after temperature compensation was taken into account using the verified temperature sensitivity coefficient ${\beta}^{\prime}$ and ground temperature obtained from the Korean Meteorological Administration (KMA) have been monitored for over one year, and the results were very consistent to those measured from the load cell, interestingly.

• Safety and Health at Work
• /
• v.11 no.2
• /
• pp.173-177
• /
• 2020

Background: Indoor air dampness microbiota (DM) is a big health hazard. Sufficient evidence exists that exposure to DM causes new asthma or exacerbation, dyspnea, infections of upper airways and allergic alveolitis. Less convincing evidence has yet been published for extrapulmonary manifestations of dampness and mold hypersensitivity syndrome). Methods: We investigated the prevalence of extrapulmonary in addition to respiratory symptoms with a questionnaire in a cohort of nurses and midwives (n = 90) exposed to DM in a Helsinki Obstetric Hospital. The corresponding prevalence was compared with an unexposed cohort (n = 45). Particular interest was put on neurological symptoms and multiple chemical sensitivity. Results: The results show that respiratory symptoms were more common among participants of the study vs. control cohort, that is, 80 vs 29%, respectively (risk ratio [RR]: 2.56, p < 0.001). Symptoms of the central or peripheral nervous system were also more common in study vs. control cohort: 81 vs 11% (RR: 6.63, p < 0.001). Fatigue was reported in 77 vs. 24%, (RR: 3.05, p < 0.001) and multiple chemical sensitivity in 40 vs. 9%, (RR: 3.44, p = 0.01), the so-called "brain fog", was prevalent in 62 vs 11% (RR: 4.94, p < 0.001), arrhythmias were reported in 57 vs. 2.4% (RR: 19.75, p < 0.001) and musculoskeletal pain in 51 vs 22% (RR: 2.02, p = 0.02) among participants of the study vs. control cohort, respectively. Conclusion: The results indicate that the exposure to DM is associated with a plethora of extrapulmonary symptoms. Presented data corroborate our recent reports on the health effects of moist and mold exposure in a workplace.

• Korean Journal of Optics and Photonics
• /
• v.22 no.4
• /
• pp.198-203
• /
• 2011

We have conducted a theoretical study to improve the detection limit of a surface plasmon resonance (SPR) sensor by co-localizing plasmonic fields and target molecules of interest. The fields were localized by nanograting antennas, while target molecules that participate in a molecular interaction were assumed to be co-localized by angled evaporation of a dielectric mask layer on the nanograting antennas. We have performed the evaluation using an overlap integral between distributions of plasmon fields and molecules and confirmed the correlation of the overlap with the sensitivity of an SPR sensor. Based on the calculated sensor characteristics, it was found that the sensitivity, if the fields and molecules are co-localized, can be as much as ten times that of non-colocalized structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2000.11a
• /
• pp.271-274
• /
• 2000

Gas sensor materials capable of detecting hydrogen gases (H$_2$) or nitrogen oxides (NO$\_$x/, primarily NO and NO$_2$) with high sensitivity have attracted much interest in conjunction with the growing concern to the protection of global environments. Beside conventional sensor materials, such as semiconductors., conducting polymers and solid electrolytes, the potential of sensor materials with a new method for detecting hydrogen gases or nitrogen oxides gas has also been tested. The breakdown voltage of porous varistors shifted to a low electric field upon exposure to H$_2$ gas, whereas it shifted to a reverse direction in an atmosphere containing oxidizing gases such as O$_3$ and NO$_2$ in the temperature range of 300 to 600$^{\circ}C$. Furthermore, it was found that the magnitude of the breakdown voltage shift, i. e. the magnitude of sensitivity, was well correlated with gas concentration, and that the H$_2$ sensitivity was improved by controlling the composition of the Bi$_2$O$_3$ rich grain boundary phase. However, NO$\_$x/ sensing properties of porous varistors have not been studies in detail. The objective of the present study is to investigate the effect of the composition of the Bi$_2$O$_3$ rich grain boundary phase and other additive such as A1$_2$O$_3$ on the hydrogen gases (H$_2$) sensing properties of porous ZnO based varistors.

• The Journal of the Korea Contents Association
• /
• v.9 no.9
• /
• pp.191-198
• /
• 2009

Advancement of technique in the $21^{st}$ century has enabled us to combine designs through diversification of materials and academic liaison, which has brought about alteration of variety of desires in our lives. Consequently, visual concern along with harmony of functional roles allows development of design that matches one's own Individuality, in which case is becoming the subject of interest. Currently, designs are being developed using various materials. This trend respects personal sensitivity and taste and thus becoming diversified. As a result of elevated standard of living, health and individuality are becoming highly concerned and accordingly, fragrance is being developed in various forms to match personal taste and character, such as one's own memory and sensitivity. Hence, I am to propose a conjugation plan about men's adornments that deviates from women's secondary design and expresses only men's character and sensitivity. First, I will engraft porosity metal with adornments and use materials that has aroma and direction of way of wearing it. Then, I will engraft visual design with the olfactory sensation to apply to ornaments, using mechanical traits and materials with aesthetic elements, which will meet the customers' sensuous demand

• Journal of the Korea Convergence Society
• /
• v.10 no.2
• /
• pp.149-158
• /
• 2019

Cyberbullying, one of the acts of cyber violence, is becoming a problem as digital devices become popular. Therefore, this study intends to provide pictograms that can communicate visually in order to raise awareness of cyberbullying prevention. 'Cyberbullying prevention pictogram' was conducted in total 6 times for 5 middle and high school boys. After analyzing the works, the results of this study are as follows. First, we investigated the change of cyberbullying recognition, empathy sensitivity, message visualization and social participation. First, the learner relaxed the burden of the art expression by using app, and the interest of the art was improved. Second, the learner recognized the seriousness of cyberbullying's violence and recognized the importance of preventing cyberbullying. Third, the learner improved sympathy sensitivity that sympathizes the suffering of cyberbullying victims. Fourth, cyberbullying prevention pictograms improved the ability to read, utilize and interpret visual images through sharing works. Fifth, the work was posted on an Instagram to give concrete action on social problems. In conclusion, we proved the effectiveness of cyberbullying prevention art class using pictograms.

• Health Policy and Management
• /
• v.31 no.2
• /
• pp.158-172
• /
• 2021

Background: Metabolic syndrome has been known as a risk of cardiovascular disease. Meanwhile, high sensitivity C-reactive protein (hs-CRP) is used as a predictor of cardiovascular disease. In this paper, we aimed to investigate the association between hs-CRP and metabolic syndrome. Method: A total of 7,633 were chosen as the study population from the 7th Korea National Health and Nutrition Examination Survey dataset (2016-2017). Our dependent variable was whether an individual had metabolic syndrome or not, and the independent variable of interest was hs-CRP which was categorized into three groups. The chi-square tests and hierarchical logistic regression analyses reflecting survey characteristics were conducted. All analyses were stratified by gender. Results: According to the adjusted model with all covariates, compared to individuals having the low risk of hs-CRP, those having its average risk were more likely to have metabolic syndrome in men (odds ratio [OR], 1.41; 95% confidence interval [CI], 1.12-1.76) and women (OR, 1.69; 95% CI, 1.33-2.16). Individuals having the high risk was not significantly different in men; however, they were more likely to have metabolic syndrome in women (OR, 2.03; 95% CI, 1.28-3.23). Conclusion: In an upcoming aging society, it is important to reduce the risk of metabolic syndrome to improve population health. This study suggests that hs-CRP may be used as a marker of the risk of metabolic syndrome in a gender-specific way, thereby contributing to enhancing awareness of the risk of metabolic syndrome among the general public.

• Transactions of the Korean hydrogen and new energy society
• /
• v.34 no.2
• /
• pp.113-121
• /
• 2023

Recently, low hydrogen carbon production technology is drawing interest due to lower production costs. Although the pace of research in this field has been accelerating, there is no well-established criteria for evaluation. The most of current evaluation methods needs information related to technology. However the technology is not enough to provide effective evaluation criteria because the technology is not fully developed. In this study, we propose an integrated Delphi-analytic hierarchy process (AHP) method and low carbon hydrogen production technology evaluation model. Experts opinion is used to provide evaluation criteria for the technology. In this study, integrated Delphi-AHP method are utilized for determining factors and calculating their numerical importance based on experts opinion. Then, sensitivity analysis is performed to verify the robustness of the analysis and scenarios of potential changes. As many as 11 factors are identified by Delphi method. Then, numerical importance of the factors are calculated by AHP. Sensitivity analysis is performed. It shows that intellectual property right (IPR) is always more important than other factors. This study proposes the numerical standard for the low carbon hydrogen production technology evaluation. The proposed model can be used for technology evaluation or commercialization.

• Journal of the Korean Society of Systems Engineering
• /
• v.12 no.1
• /
• pp.73-87
• /
• 2016

Combining power generation and water production by desalination is economically advantageous. Most desalination projects use fossil fuels as an energy source, and thus contribute to increased levels of greenhouse gases. Environmental concerns have spurred researchers to find new sources of energy for desalination plants. The coupling of nuclear power production with desalination is one of the best options to achieve growth with lower environmental impact. In this paper, we will per-form a sensitivity study of coupling nuclear power to various combinations of desalination technology: {1} thermal (MSF [Multi-Stage Flashing], MED [Multi-Effect Distillation], and MED-TVC [Multi-Effect Distillation with Thermal Vapour Compression]); {2} membrane RO [Reverse Osmosis]; and {3} hybrid (MSF-RO [Multi-Stage Flashing & Reverse Osmosis] and MED-RO [Multi-Effect Distillation & Reverse Osmosis]). The Korean designed reactor plant, the APR1400 will be modeled as the energy production facility. The economical evaluation will then be executed using the computer program DEEP (Desalination Economic Evaluation Program) as developed by the IAEA. The program has capabilities to model several types of nuclear and fossil power plants, nuclear and fossil heat sources, and thermal distillation and membrane desalination technologies. The output of DEEP includes levelized water and power costs, breakdowns of cost components, energy consumption, and net saleable power for any selected option. In this study, we will examine the APR1400 coupled with a desalination power plant in the Kingdom of Saudi Arabia (KSA) as a prototypical example. The KSA currently has approximately 20% of the installed worldwide capacity for seawater desalination. Utilities such as power and water are constructed and run by the government. Per state practice, economic evaluation for these utilities do not consider or apply interest or carrying cost. Therefore, in this paper the evaluation results will be based on two scenarios. The first one assumes the water utility is under direct government control and in this case the interest and discount rate will be set to zero. The second scenario will assume that the water utility is controlled by a private enterprise and in this case we will consider different values of interest and discount rates (4%, 8%, & 12%).

• Microbiology and Biotechnology Letters
• /
• v.36 no.4
• /
• pp.360-365
• /
• 2008

For the screening of residual antibiotics in foods, bioassays and microbiological inhibitor tests are commonly applied. These methods are tested by the various susceptibility of bacteria against different kinds of antibiotics. However, the sensitivity of bioassay is generally insufficient to detect some residual antibiotics at level of interest. This study was performed to investigate the detection limit of variable antibiotics of the bioassay and to improve the sensitivity to some antibiotics. The sensitivity of bioassay using Bacillus megaterium ATCC 9885, B. subtilis ATCC 6633, B. cereus ATCC 11778 and Geobacillus stearothermophilus ATCC 10149 was low in the detection of macrolides, quinolones, chloramphenicol, and monensin. On the contrary, Micrococcus luteus ATCC 9341 showed high sensitivity to macrolides and Escherichia coli ATCC 11303 was highly sensitive to quinolones and aminoglycosides. Consequently, both strains would be useful to improve sensitivity of bioassay with a wide detection range.