• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.4D
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• pp.649-659
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• 2006

Recently there has been huge efforts to improve performance in construction process by applying emerging techniques such as the Lean principle and Just-in-time concept. However, little achievement as we expected has come out in reality due to the lack of strategy to set a definite goal of the execution and differences of personal viewpoints on construction productivity. Accordingly, it is the most important to promote the circumstances for the construction process improvement by quantifying the goals of respective unit activity groups. This research explores feasible solutions for the improvement of construction projects performance by combining the six-sigma principle for the generic administrative innovation based on the idea of construction process performance. For this purpose, mutual comparisons of various current approaches are performed in an attempt to establish the advantages in applying six-sigma idea and to provide its fundamental strategy. Furthermore, through a case study with the simulation of applying six-sigma to a unit activity group in construction process, this paper verifies that the overall performance improves as the degree of sigma level gets advanced.

• Journal of Industrial Convergence
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• v.21 no.8
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• pp.1-12
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• 2023

The purpose of the study is to analyze the impact of blended learning's external classroom formats and internal teaching strategies, which has been implemented in university classes due to COVID-19, on students' academic achievement and learners' perceptions, as well as to provide insights into the desirable direction of online education. The study was conducted during the 1st semester of 2022 at G University, targeting students taking Calculus I. The experimental group consisted of 117 students, while the control group consisted of 707 students. Blended learning, involving a combination of face-to-face classes, online classes, and mixed teaching methods, was implemented, and academic achievement and learner perceptions were assessed. The research findings indicate that compared to solely online classes, adopting a blended learning approach with online classes before the midterm and face-to-face classes afterwards resulted in a decline in academic achievement. The unprepared and simplistic external format of blended learning was found to be ineffective, however, a blended learning model consisting solely of online classes, incorporating a mix of asynchronous and synchronous instruction, demonstrated positive learner perceptions. Additionally, utilizing technology in the teaching strategies yielded positive outcome.

• Journal of dental hygiene science
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• v.23 no.4
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• pp.351-360
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• 2023

Background: The purpose of this study is to investigate the tooth whitening effect of Listerine Healthy White and provide effective management of extrinsic discoloration by comparing the whitening effects of existing whitening products. Methods: The included study four groups: those using whitening gel, whitening toothpaste, and Listerine Healthy White and a control using artificial saliva. Each group received 40 bovine tooth specimens, which were stained with commonly consumed tooth-coloring-inducing foods; black tea, black coffee, and instant noodles for 72 hours. The specimens were treated with tooth whitening materials for 5 weeks, after which the lightness (L^*) was measured weekly using a spectrophotometer. Results: There was a significant difference in lightness among the groups between the 1st and 5th week of treatment for all tooth-coloring-inducing foods (p<0.05). When comparing the changes in lightness values from before whitening to the 5th week of whitening for all tooth-coloring-inducing foods, the order of change was as follows: whitening gel, whitening toothpaste, Listerine Healthy White, and artificial saliva. Listerine Healthy White showed a significant whitening effect for all tooth-coloring-inducing foods (p<0.05). Particularly, changes in lightness values for specimens stained by black tea after 5 weeks of whitening were in the following order: whitening gel (21.72), whitening toothpaste (14.89), Listerine Healthy White (12.91), and artificial saliva (3.85). For specimens stained by black coffee, the changes in lightness values were in the following order: whitening gel (12.99), whitening toothpaste (9.66), Listerine Healthy White (7.91), and artificial saliva (3.12). Lastly, changes in lightness values for specimens stained by instant noodles were as follows: whitening gel (10.84), whitening toothpaste (9.85), Listerine Healthy White (7.71), and artificial saliva (2.61). Conclusion: Listerine Healthy White exhibits continuous whitening effects over time, and for consumers seeking convenient ways to achieve tooth whitening effects at home, consistent use of Listerine Healthy White is recommended.

• Journal of Life Science
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• v.34 no.6
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• pp.385-392
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• 2024

Hot pepper (Capsicum annuum L.) is a valuable plant that is widely used worldwide for food and medicinal purposes. This study compared ethanol extracts of five native Korean varieties (Yuwol-cho, Subi-cho, Sumihyang, Gounbit, and Chilseong-cho) and five improved varieties (Dabok, Cheongyang, Chungseong, Olbokhap, and Shin-honggildong) of peppers cultured in Korea. The extracts were analyzed for color difference, polyphenol content, and their antioxidant, antidiabetic, and antithrombotic activities. The extracts of the improved varieties exhibited higher levels of redness and lower levels of yellowness compared to the native varieties. Polyphenol and flavonoid content analysis revealed significantly higher levels in the Yuwol-cho and Sumihyang varieties, which also exhibited scavenging activities in 1,1-diphenyl-2-picryl hydrazyl anion-, 2,2-azobis(3-ethylbenzothiazoline-6-sulfonate) cation-radical scavenging, and reducing power assay. The Chilseong-cho, Yuwol-cho, and Dabok varieties showed significantly higher nitrite scavenging activity. Antidiabetic activity based on α-glucosidase inhibition was observed in the Subi-cho, Sumihyang, and Gounbit extracts. Evaluation of antithrombotic activity showed that the Yuwol-cho extract prolonged thrombin time by 1.61 times compared to the solvent control at a concentration of 5 mg/ml, while the Dabok extract prolonged prothrombin time and activated partial thromboplastin time by 1.33 times and 2.21 times, respectively. All pepper extracts showed no erythrocyte hemolysis activity up to a concentration of 5 mg/ml. Our results suggest that native Korean peppers have the potential to serve as valuable sources of antioxidant, antidiabetic, and antithrombotic agents. This research also indicates the possibility of replacing improved pepper varieties, which incur significant seed usage fees, with native Korean pepper varieties.

• Food Science and Preservation
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• v.30 no.4
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• pp.683-690
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• 2023

The study was conducted to confirm the possibility of producing alcohol beverages from Dae-hong peaches. Upon examining the quality characteristics of distilled soju using Dae-hong peaches, the alcohol content was 1.12 to 1.16 times higher than that from the atmospheric distillation method. Soju with 20 % peach extract content had the highest alcohol content and the lowest volatile acid content, indicating a low possibility of causing irritating odors. Acetaldehyde was 1.3-1.94 times lower in vacuum-distilled soju, and methanol was not detected in all samples. The absorbance value of furfural, a burnt component generated during distillation is high in atmospheric distillation, which can cause irritating odors. Upon examining the volatile fragrance components, isoamylalcohol and 1-propanol were found to be the main components, both of which were the highest in the treatment group with 20 % peach extract content. The electronic nose analysis revealed that this group showed the most opposing flavor patterns to the control group, and when distilled under reduced pressure with 20 % addition of Dae-hong peaches can produce high-quality soju.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.69 no.2
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• pp.78-87
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• 2024

The risk of global warming is increasing due to rapid climate change and increased greenhouse gas (GHG) emissions. Among the greenhouse gases, methane has a strong warming effect; in particular, 51.2% of the agricultural sector's methane emissions are from flooded rice fields. According to the current standard rice cultivation method, rice is grown during the maximum tillering stage with an intermittent drainage period of approximately 2 weeks. During the flooding period, methane-producing bacteria are active, but the activity of methane-producing bacteria and the amount of methane gas produced are reduced when the soil becomes oxidized through watering. Accordingly, this study used multiple-sensing technology to analyze the growth response according to the intermittent drainage period and to identify the extended intermittent drainage period with less impact on rice production. The equipment used for growth observations included NDVI, PRI, and IR sensors. The results confirmed that growth indices related to stress, such as NDVI and PRI, were not significantly different from those of the control when treated within 3 weeks of drainage, but drastically decreased when the drainage period was extended beyond 4 weeks. These results appear to result from the fact that soil water content (volumetric water content) also dropped to below 20% 4 weeks after irrigation, creating actual drought stress conditions. The 22^nd day after treatment, when the soil moisture content reached 20%, was considered the point in time when drought stress conditions were formed. The point at which the SPAD value decreased to 0.6% of normal was estimated to be 23.5 days after treatment by using the regression equation between NDVI and SPAD.

• Journal of Korean Society of Forest Science
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• v.113 no.3
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• pp.308-318
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• 2024

Forest fuel management plays a crucial role in the proper management of frequent and large-scale forest fires worldwide. This study evaluated the impact of fuel management on reducing forest fire risk by through surface fire behavior through laboratory experiments and simulations using the Wildland Fire Dynamics Simulator. For Pinus densiflora litter, fuel conditions were established based on field surveys in Goseong-gun, Gangwon-do, focusing on control, 20% thinning, and 40% thinning sites. Results indicated that visible flame height, vertical temperature distribution, and maximum heat release rate tended to decrease with higher thinning intensity, implying a lower forest fire risk. Overall, the WFDS simulations produced higher values compared to the laboratory experiments, but the trends were similar. The results of this study can serve as fundamental data for evaluating forest fire risk based on thinning intensity and establishing a research foundation for fire prevention.

• Journal of Preventive Medicine and Public Health
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• v.31 no.3 s.62
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• pp.424-439
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• 1998

Urinary cadmium is used as a sensitive indicator for internal Cd dose, and increased excretion of $N-acetyl-\beta-D-glucosaminidase(NAG)$, $\beta_2-microglobulin(MG)$ and total protein are useful indices for renal dysfunction by chronic exposure to Cd. The target group was 184 inhabitant(82 men and 102 women) in an abandoned mine area known as exposure to low level Cd. The control group was took 160 individuals(64 men and 96 women) in Cd not-exposed area. Urinary Cd concentration was significantly higher in the target group than the control. The geometric mean of urinary Cd for male was $2.56{\mu}g/\ell,\;2.80{\mu}g/g$ creatinine and $2.50{\mu}g/S.G.$ in the target group and $1.19{\mu}g/\ell,\;1.36{\mu}g/g$ creatinine and $1.17{\mu}g/S.G.$ in the control. For female $2.69{\mu}g/\ell,\;3.94{\mu}g/g$ creatinine and $2.63{\mu}g/S.G.$ in the target group and $1.27{\mu}g/\ell,\;1.97{\mu}g/g$ creatinine and $1.25{\mu}g/S.G.$ in the control, respectively. In addition, urinary Cd of the target group had affected by the period of residence and dietary habit for the rice and the vegetables from the target area. These findings suggest the chronic exposure to Cd of the target population. Mean excretion of urinary NAG, $\beta_2-MG$ and total protein were not significant between two groups. In the target group, urinary NAG activity and total protein were significantly correlated with urinary Cd, but $\beta_2-MG$ was not related. Urinary excretion of NAG, $\beta_2-MG$ and total protein were significantly increased in $10\leqq$ than in <2 of urinary Cd level. In $2\sim10$ group of urinary Cd level, the excretion of NAG significantly increased while not showed for $\beta_2-MG$. In present study, urinary excretion of NAG was relatively sensitive than $\beta_2-MG$ in chronic exposure population to low level Cd.

• Tuberculosis and Respiratory Diseases
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• v.44 no.2
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• pp.349-359
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• 1997

Background : The signal pathways and their precise roles for acute respiratory distress syndrome caused by endotoxin (ETX) has not been established. Since there has been several in vitro experiments suggesting that activation of protein kinase C (PKC) pathway may be responsible for endotoxin-induced inflammatory reaction, we performed in vivo experiments in the rats with the hypothesis that PKC-inhibition can effectively prevent endotoxin-induced acute lung injury. Methods : We studied the role of PKC in ETX-induced ALI using PKC inhibitor (staurosporine, STP) in the rat Specific pathogen free male Sprague-Dawley weighted from 165 to 270g were used for the study. Animals were divided into the normal control (NC)-, vehicle control (VC)-, ETX-, PMA (phorbolmyristateacetate)-, STP+PMA-, and STP+ETX-group. PMA (50mg/kg) or ETX (7mg/kg) was instilled through polyethylen catheter after aseptic tracheostomy with and without STP (0.2mg/kg)-pretreatment STP was injected via tail vein 30min before intratracheal injection (IT) of PMA or ETX. Bronchoalveolar lavage (BAL) was done 3-or 6-hrs after IT of PMA or ETX respectively, to measure protein concentration, total and differential cell counts. Results : The results were as follows. The protein concentrations in BALF in the PMA- and ETX-group were very higher than that of VC-group (p<0.001). When animals were pretreated with STP, the %reduction of the protein concentration in BALF was $64.8{\pm}8.5$ and $30.4{\pm}2.5%$ in the STP+PMA- and STP+ETX-group, respectively (p = 0.028). There was no difference in the total cell counts between the PMA-and VC-group (p = 0.26). However the ETX-group showed markedly increased total cell counts as compared to the VC- (p = 0.003) and PMA-group (p = 0.0027), respectively. The total cell counts in BALF were not changed after pretreatment with STP compared to the PMA- (p = 0.22) and ETX-group (p = 0.46). The percentage of PMN, but not alveolar macrophage, was significantly elevated in the PMA-, and ETX-group. Especially in the ETX-group, the percentage of PMN was 17 times higher than that of PMA (p < 0.001). The differential cell counts was not different between the PMA and STP+PMA On the contrary the STP+ETX-group showed decreased percentage of PMN (p = 0.016). There was no significant relationship between the protein concentration and the total or differential cell counts in each group. Conclusion : Pretreatment with PKC-inhibitor (staurosporine) partially but significantly inhibited ETX-induced ALI.

• Journal of The Korean Society of Grassland and Forage Science
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• v.38 no.2
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• pp.106-111
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• 2018

This study was conducted to investigate the relationship between changes of rumen microflora and bloat in Jersey cow. Jersey cows (control age: 42 months, control weight: 558kg; treatment age: 29 months, treatment weight 507kg) were fed on the basis of dairy feeding management at dairy science division in National Institute of Animal Science. The change of microbial population in rumen was analyzed by using next generation sequencing (NGS) technologies due to metabolic disease. The diversity of Ruminococcus bromii, Bifidobacterium pseudolongum, Bifidobacterium merycicum and Butyrivibrio fibrisolvens known as major starch fermenting bacteria was increased more than 36-fold in bloated Jersey, while cellulolytic bacteria community such as Fibrobacter succinogenes, Ruminococcus albus and Ruminococcus flavefaciens was increased more than 12-fold in non-bloated Jersey. The proportion of bacteroidetes and firmicutes was 33.4% and 39.6% in non-bloated Jersey's rumen, while bacteroidetes and firmicutes were 24.9% and 55.1% in bloated Jersey's. In conclusion, the change of rumen microbial community, in particular the increase in starch fermenting bacteria, might have an effect to occur the bloat in Jersey cow.