• Journal of the Korean Society of Safety
• /
• v.38 no.3
• /
• pp.61-68
• /
• 2023

This study performed a structural performance evaluation of a system scaffolding for elevator installation work developed in previous studies. The structural performance was evaluated via a structural test conducted to apply the working load specified in the design standard. The deflection of the horizontal member and the stress of each member constituting the system scaffolding were measured. Consequently, the structural safety evaluation including structural behavior and required performance was performed using the deflection and stresses measured from the structural test. The structural test and safety evaluation results based on the heavy working load corresponding to the design load indicated that the deflection, which is the performance criterion of the horizontal member, did not exceed the allowable value. Further, each member's stress, which is a safety evaluation indicator, did not exceed the allowable strength for both horizontal and vertical members with bending behavior and fordable bracing with tensile behavior, while also satisfying the required safety factor. In addition, the results confirmed the safety against deformation, partial damage, and destruction owing to excessive and maximum load. Therefore, the system scaffolding developed in this study satisfies both the structural performance and safety required by the design standards; thus, it can be applied to elevator installation work sites.

• Smart Structures and Systems
• /
• v.30 no.4
• /
• pp.385-395
• /
• 2022

Detecting cracks on a concrete structure is crucial for structural maintenance, a crack being an indicator of possible damage. Conventional crack detection methods which include visual inspection and non-destructive equipment, are typically limited to a small region and require time-consuming processes. Recently, to reduce the human intervention in the inspections, various researchers have sought computer vision-based crack analyses: One class is filter-based methods, which effectively transforms the image to detect crack edges. The other class is using deep-learning algorithms. For example, convolutional neural networks have shown high precision in identifying cracks in an image. However, when the objective is to classify not only the existence of crack but also the types of cracks, only a few studies have been reported, limiting their practical use. Thus, the presented study develops an image processing procedure that detects cracks and classifies crack types; whether the image contains a crazing-type, single crack, or multiple cracks. The properties and steps in the algorithm have been developed using field-obtained images. Subsequently, the algorithm is validated from additional 227 images obtained from an open database. For test datasets, the proposed algorithm showed accuracy of 92.8% in average. In summary, the developed algorithm can precisely classify crazing-type images, while some single crack images may misclassify into multiple cracks, yielding conservative results. As a result, the successful results of the presented study show potentials of using vision-based technologies for providing crack information with reduced human intervention.

• Korean Journal of Organic Agriculture
• /
• v.25 no.3
• /
• pp.587-602
• /
• 2017

Correlations of soil and leaf nutrients and growth of young 'Enterprise' apple (Malus ${\times}$ domestica Borkh.) trees were analyzed with tree damage, such as Japanese beetle (JB; Popillia japonica Newman)-damaged leaves, vole damage to trunk, tree mortality, and weed density in a certified organic orchard in warm and humid environment of Southern USA. Interaction treatments of four mulch and three fertilizers were applied around trees as follows: mow-and-blow (MB), shredded paper (SP), wood chips (WC), and green compost (GC) as a mulch, with no fertilizer (NF), poultry litter (PL), and commercial organic fertilizer (CF) as a fertilizer applied in April. Vole damage to trunk and weed density were little correlated with mineral nutrients and tree growth. JB-damaged leaves were highly stimulated to 26.5% in GC-treated plots while tree mortality were increased by MB treatments. Biomass production per tree was approximately 3,700 g on the WC- and GC-treated plots, which was two times higher than those values observed on the other two mulch plots. JB-damaged leaves tended to get worse when nutrients in soil and leaf increased through the correlation analysis, with a strong positive relationship ($r^2=0.585$) observed between JB-damaged leaves and trunk cross sectional area, a vegetative indicator. Tree mortality was more negatively associated with nutrient contents and growth of trees than those of soil nutrients. Wood chips was considered for a local organic mulch materials to increase organic matter contents and to produce healthy young trees in Southern USA, with control insect, such as beetle, and vole density in an orchard habitat.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.34 no.4
• /
• pp.277-282
• /
• 2014

Recently, much attention has been paid to nonlinear ultrasonic technology as a potential tool to assess hidden damages that cannot be detected by conventional ultrasonic testing. One nonlinear ultrasonic technique is measurement of the resonance frequency shift, which is based on the hysteresis of the material elasticity. Sophisticated measurement of resonance frequency is required, because the change in resonance frequency is usually quite small. In this investigation, the nonlinear electromagnetic acoustic resonance (NEMAR) method was employed. The NEMAR method uses noncontact electromagnetic acoustic transducers (EMATs) in order to minimize the effect of the transducer on the frequency response of the object. Aluminum plate specimens that underwent three point bending fatigue were tested with a shear wave EMAT. The hysteretic nonlinear parameter ${\alpha}$, a key indicator of damage, was calculated from the resonance frequency shift at several levels of input voltage. The hysteretic nonlinear parameter of a damaged sample was compared to that of an intact one, showing a difference in the values.

• Journal of Veterinary Clinics
• /
• v.27 no.3
• /
• pp.216-219
• /
• 2010

The purpose of this study is to establish experimental canine skin barrier disruption model, the study was designed to observe calcium ion in skin frozen tissue of canine skin and also the modulation of calcium ion distribution of normal skin with disrupted skin such as clipping, acetone, tape stripping damages according to time. To compare the changes of calcium ion gradient after damages, the distribution of calcium ion in the canine epidermis was visualized by blotting to gel containing chemical indicator (Calcium Green-1) with fluorescent microscope and the effects of skin barrier damages were examined according to time. Three mins and 1hr after acetone damage, the gradations of epidermis and hair follicle showed more radiant and disappeared after 48 hrs. On the contrary, 3mins and 1hr after tape stripping damage, the gradations showed more radiant than those of acetone damage, and these gradations were stabilized after 48 hrs. The method we presented here could show the visual image of the calcium ions in frozen tissue without further preparation, and it might be useful to investigate the role of calcium ion in the canine epidermal barrier recovery, however, it might be need further methodological improvement to get accurate quantitative information.

• Korean Journal of Environmental Biology
• /
• v.36 no.4
• /
• pp.498-506
• /
• 2018

The purpose of this study is to examine the restorative effect of Semisulcospira libertina extract, on damaged liver cells induced by D-galactosamine in rats. Treatment of damaged liver cells with S. libertina extract significantly reduced local fatty degeneration, and inflammatory cell necrosis, to levels similar with the undamaged control group. In addition, S. libertina extracts were found to reduce plasma levels of liver damage indicator enzymes, such as AST, ALT, LDH and ALP, to control levels. It also reduced lipid peroxides, and lipid contents within damaged liver tissues. This suggests that S. libertina extract has a restorative effect on liver cells, thus reducing release of damage-associated liver enzymes, and oxidative degradation of lipids. Also, S. libertina extracts were found to be involved in recovery of damaged cells from inflammatory response by suppressing expression of $TNF-{\alpha}$, which leads to tissue injury and necrosis, whereas inducing expression of HO-1 that protects cells during inflammation. Thus, S. libertina extract restores liver tissue from necrosis and fibrosis, as well modulates expression of inflammation-related genes against liver damage. Our findings suggest that S. libertina extract is an effective medicinal resource, for improving and recovering liver cells from hepatic injury.

• Journal of Chest Surgery
• /
• v.31 no.2
• /
• pp.125-133
• /
• 1998

This study was designed to identify the efficiency of serum troponin-T(s-TnT) level as a diagnostic indicator for the perioperative myocardial damage with open heart surgery(OHS) and to compare with the conventional myocardial enzyme tests such as isoenzyme fraction of creatine kinase(% CK-MB) and isoenzyme ratio of lactate dehydrogenase(LDH1/LDH2 ratio). The study was performed on 30 adult patients who underwent OHS from Jan. 1996 to June 1996 at Inje University Pusan Paik Hospital, and they were divided into two groups accor- ding to aortic clamping time(ACT) duration : group I(ACT＜60 minutes, n=15); group II (ACT＞60 minutes, n=15). S-TnT, % CK-MB, and LDH1/LDH2 ratio were measured in serial blood samples from all subjected patients. The results were obtained as follows. 1. In both groups, s-TnT concentrations increased gradually during OHS and elevated significantly at CPB-10(p＜0.001). The peak level was noticed at POD 1 in group I(1.10 $\pm$0.19 ng/ml), whereas, at CPB-off in group II(1.88$\pm$0.42 ng/ml). The elevated levels remained until POD 7 in both groups. 2. %CK-MB was risen significantly with the initiation of operations(p＜0.001) and the peak levels were noticed at CPB-off in both groups(7.14$\pm$0.86% in group I, 10.69$\pm$1.27% in group II). Thereafter, these levels returned to normal values at POD 3. 3. There were no significant changes in the values of LDH1/LDH2 ratio during and after OHS compared with the control levels(p＞0.05). 4. The serial changes of s-TnT were relatively well correlated with those of changes of % CK-MB(r=0.64, p＜0.05). 5. The serial s-TnT levels were significantly higher in group II than group I from B-ACR to POD 1(p＜0.05), suggesting that duration of aortic clamping time was a major factor concerned with perioperative myocardial injury. In conclusion, measurement of s-TnT is a very useful indicator in assessing the myocardial cell damage and therefore it is expected that serial checking and evaluation of the s-TnT is very available for identification of the perioperative myocardial damage and for postoperative cares in patients with OHS.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.41 no.6
• /
• pp.84-95
• /
• 2013

Recently, to prevent damage to the landscape, outstanding landscape areas have been designated in advance. In particular, as a fundamental way to evaluate landscape elements, landscape diversity is an important criterion to assess an area with a high conservative value. Therefore, the purpose of this study is to develop a quantitative evaluation model of landscape diversity based on landscape elements and to verify the model by applying it to the study sites. The assessment indicators derived from the literature analysis are topography, vegetation, land-use pattern, and unusual landscape. Topography diversity is subdivided into land undulation and land-form. Vegetation diversity is subdivided into plant community diversity and stratification diversity. To quantitatively analyse each indicator's diversity, SHDI was selected as the central metric. All of the quantitative measures were implemented by using the statistical tool, FRAGSTATS. Through the process of each indicator's standardization and summary, the final landscape diversity index was calculated. The results of the study are significant as it was the initial study of landscape diversity evaluation to seek applicability. However, the results of the Landscape Diversity Evaluation Model in this study based on 4 indicators synthetically demonstrate that more than one or two outstanding indicators can be underrated. Therefore, each 4 assessment indicator results should be considered individually. Furthermore, using the maximum value for each indicator's standardization reflects that it is necessary to analyse various examples to obtain higher objectivity later.

• Journal of Climate Change Research
• /
• v.8 no.3
• /
• pp.257-264
• /
• 2017

Carbon capture and storage (CCS) technology has been suggested as an ultimate strategy for mitigating climate change. However, potential leakage of $CO_2$ from the CCS facilities could lead to serious damage to environment. Plants can be a bio-indicator for $CO_2$ leakage as a cost-effective way, although plants' responses vary with plant species. In this study, a greenhouse experiment was conducted to investigate the relation between the $CO_2$ tolerance of corn species and the initial physiological responses to the elevated soil $CO_2$ concentration. Treatment groups included CI (99.99% $CO_2$ gas injection) and BI (no gas injection). Mean soil $CO_2$ concentration for the CI treatment was 19.5~39.4%, and mean $O_2$ concentration was 6.6~18.4%. The soil gas concentrations in the BI treatment were at the ambient levels. In the CI treatment, chlorophyll content was not decreased until the $13^{th}$ day of the $CO_2$ injection. On the $15^{th}$ day, leaf starch content and stomatal conductance were increased by 89% and 25% in the CI treatment compared to the BI treatment, respectively. This might be due to the compensatory reaction of corn to avoid high soil $CO_2$ stress. However, the prolonged $CO_2$ injection decreased chlorophyll content after 13 days. After $CO_2$ injection, plant biomass was reduced by 25% in the CI treatment compared to the BI treatment. Due to the inhibited root growth, leaf phosphorous and potassium contents were decreased by 54% on average in the CI treatment. This study indicates that corn has a high tolerance to soil $CO_2$ concentration of 30% for 2 weeks by its compensatory reactions such as an maintenance of chlorophyll content and an increase in stomatal conductance.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.28 no.6
• /
• pp.906-917
• /
• 2022

This study aimed to compare differences according to categories of fishery and marine environmental policies for the (estimated) amount of fishery waste generated by fishing, and to analyze the correlation between associated independent and dependent variables. The independent variables were divided into three dif erent sectors. The first sector included precautionary policies that observed eco-friendly fishing support program, institutional prevention activities, and physical barriers installation. The second sector with the current management policies included the relevant vessel operations, establishment of fishery order, fishery restructuring, and fishery ground clean-up. Thirdly, post-response policies comprised the litter purification from river to shoreline, the collection and removal of marine, sedimentary, and floating debris, purchasing salvaged debris generated while fishing, fishery waste disposal, and repairing damage caused by marine litter. The indicator used was the settlement amount by each program. The dependent variable was the estimated amount of fishery waste and the indicator was the sum of the loss of traps and gill nets and the loss of their appendages. According to the results of Kruskal-Wallis Test, the estimated amount of fishery waste was highest in the East Sea in terms of sea area and the highest in the Si(city) according to basic local municipality. The settlement amount related to the marine environment services was largest in the Gun(county). Further, there were significant differences between Gun(county) and the other regions(Si(city) and Gu(autonomous district)) with respect to most variables. The variables related to the estimated amount of fishery debris were the project purchasing salvaged debris generated while fishing and fishery waste disposal program in the post-response policies.