• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.177-184
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• 2010

This study was performed to determine the effects of filling materials on the physical properties of permeable polymer concrete. The filling materials were ground calcium carbonate, ground granulated blast furnace slag and fly ash. In this experiment, permeable polymer concrete mixtures with unsaturated polyester resin contents from 5 to 7 weight %, filler/resin ratio of 0~2.0 and crushed coarse aggregate passing 15 mm sieve were prepared and coefficient of permeability, void ratio, compressive strength and flexural strength were tested. As the test results, increase in the strength and decrease in the coefficient of permeability of the permeable polymer concrete were generally observed with increasing the resin contents and filler/resin ratio. The compressive and flexural strength of the permeable polymer concrete were in the range of 8.0 to 35.0 MPa and 2.0 to 9.0 MPa respectively and the highest strength was shown at the mixtures with 7 weight % unsaturated polyester resin contents, 2.0 ratio of filler/resin and filler of ground calcium carbonate. On the other hand, in the level of 20 MPa compressive strength, the mixtures with filler of fly ash was shown as the most economic permeable polymer concrete.

• Journal of the Korea Knowledge Information Technology Society
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• v.13 no.3
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• pp.327-339
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• 2018

This study is on the elderly people's use and experience of pet robots (companion robots). Applying companion robots for the elderly's daily lives can enhance their quality of life. Leisure is main activity of the elderly who are out of work. Therefore, the quality and diversity of leisure can affect the quality of their life. Companion Robots could provide them with more advanced and interesting experiences. Around the world, population aging becomes one of the most important trends in each country. The social and economic burden of aging is serious challenge on sustainability of the world, including S. Korea. The authors examine use of Companion Robots for elderly (from 50 years old to 90 years old). In this experiment, the authors study and measure many factors including system quality, interface quality, displeasure, enjoyment, willingness to reuse, perception on new technology. In regression analysis, intimacy(t=-2.006, p<.05) is significant factor on displeasure of Companion Robot. In another regression, displeasure of Companion Robot (independent variable) is significant factor on enjoyment(t=-3.327, p<.01) and willingness to reuse(t=-2.636, p<.01). Therefore, when elderly one feels less displeasure of Companion Robot, he/she feels more enjoyment and willingness to reuse. As a result, the elderly who don't familiar to new technology could improve quality of life and leisure activity by using companion robot.

• Asia Marketing Journal
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• v.15 no.3
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• pp.97-115
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• 2013

This paper was motivated by two gaps in the extant literature on brand portfolio planning. First, research has shown that, as the number of products connected to a brand increases, the extended product receives more favorable evaluations. However, this result was obtained by comparing two brands with different number of products while controlling the brands' breadths. Hence one may question if the above result would hold when the brand is narrow as well as broad. Second, the literature has investigated the effect of brand breadth on the perceived fit and evaluations of an extended product within a relatively limited range ("narrow vs. broad") and not considered the case of a "very broad" brand. To address these gaps, we propose two hypotheses: 1) the effects of the number of products associated with a brand on the perceived fit and evaluations of a moderately far brand extension are moderated by the brand's breadth (H1); and 2) the relationship between a brand's breadth and a moderately far extension's perceived fit and evaluations looks like an inverse-U shape (H2). Study 1 was conducted to test H1. Study 1 employed a 2 × 2 within-subjects design in which the first factor was the number of products (small (2) or large (5)), and the second factor was brand breadth (narrow or broad). We measured brand breadth as the perceived similarity among products associated with a brand. Participants provided the perceived fit and evaluations of an extended product. Study 2 was conducted to test H2 as well as to replicate Study 1 in a more general setting and with different products. It employed a 2 × 3 within-subjects design, in which the first factor was the number of products (small (2) or large (5)), and the second factor was brand breadth (narrow, broad, or very broad). The results from two experiments support both hypotheses. This paper contributes to the literature on brand extensions in two ways. First, it broadens our understanding of the effects of product number and brand breadth on extended product evaluations by considering the two factors jointly. Second, we believe this study to be the first to present evidence that brand breadth can exert an inverted U-shape effect on the perceived fit and evaluations of an extended product. The results also offer implications for marketers. First, marketers should heed the finding that adding similar products to a narrow brand does not help the brand's extension launch. Second, the finding that the relationship between brand breadth and extended product evaluations might not be linear provides practical implications. While a narrow brand should not keep launching close extensions, nor should a broad brand continue producing far extensions to broaden its breadth. A firm with a broad corporate or family brand might want to consider introducing a new brand instead of adding dissimilar products under the brand umbrella.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.5
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• pp.113-119
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• 2023

Most infrastructure structures were completed during periods of economic growth. The number of infrastructure structures reaching their lifespan is increasing, and the proportion of old structures is gradually increasing. The functions and performance of these structures at the time of design may deteriorate and may even lead to safety accidents. To prevent this repercussion, accurate inspection and appropriate repair are requisite. To this end, demand is increasing for computer vision and deep learning technology to accurately detect even minute cracks. However, deep learning algorithms require a large number of training data. In particular, label images indicating the location of cracks in the image are required. To secure a large number of those label images, a lot of labor and time are consumed. To reduce these costs as well as increase detection accuracy, this study proposed a learning structure based on mean teacher method. This learning structure was trained on a dataset of 900 labeled image dataset and 3000 unlabeled image dataset. The crack detection network model was evaluated on over 300 labeled image dataset, and the detection accuracy recorded a mean intersection over union of 89.23% and an F1 score of 89.12%. Through this experiment, it was confirmed that detection performance was improved compared to supervised learning. It is expected that this proposed method will be used in the future to reduce the cost required to secure label images.

• Korean Journal of Environmental Biology
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• v.41 no.4
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• pp.455-462
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• 2023

Southern root-knot nematode (SRKN, Meloidogyne incognita) is known to be responsible for annual economic losses of 38.2 million USD in cucumber cultivation in Korea. Nematicides are frequently used to manage SRKN in plastic greenhouses. A field experiment was conducted to assess the effect of a soil fumigant (dimethyl disulfide, DMDS) and a non-fumigant (fluopyram, FL) against SRKN during the winter fallow season in a greenhouse from October to December. Nematicidal efficacy was assessed at 43 days after treatment, and the root gall index was measured 4 months after transplanting cucumber seedlings. DMDS effectively reduced second-stage SRKN juvenile density with 91% control efficacy, while FL showed no control efficacy against SRKN. Root gall index values were significantly different(p=0.020) in DMDS treatment and controls at 1.0±0.00 and 4.3±0.58, respectively. This study showed that DMDS could be considered an effective nematicide for controlling SRKN in the fallow period in winter.

• Journal of Industrial Convergence
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• v.22 no.7
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• pp.1-13
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• 2024

Among e-government services, the intelligent CCTV control platform is a screening control service that utilizes artificial intelligence to display major objects such as people, cars, etc. to control personnel when they appear on CCTV. The operation of an intelligent CCTV control platform is expected to improve the quality of life of citizens by enabling rapid response in the event of an emergency and increasing the resolution of complaints. In this study, the benefits of the intelligent CCTV control platform, a non-market good, were estimated by applying the contingent valuation method (CVM), a choice experiment technique, to estimate the average willingness to pay per household and calculate the social benefits. As a result of the analysis, the average willingness to pay per household was estimated to be KRW 6,908 per year, and the economic benefits for the country as a whole were estimated to be about KRW 150.4 billion per year. This study is of academic significance as it extends the application of CVM to the field of intelligent e-Government services. The Intelligent CCTV control platforms is being actively discussed, this study has practical implications in that the benefits were estimated in monetary value.

• Economic and Environmental Geology
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• v.43 no.3
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• pp.235-248
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• 2010

To construct the standard methods for evaluation of physicochemical characteristics of tailings in Korea, specific gravity, paste pH, grain size, mineral compositions and heavy metal concentrations of total 26 tailings from 21 metallic mines were analyzed. Specific gravity of tailings ranged from 2.61 to 4.31 (avg. 3.04), and sand and silt grain were dominant in the tailings. Ranges of paste pH were 2.1-9.5 in tailings (7.1-9.2 at magmatic, skarn and hydrothermal replacement deposits and 2.1-9.5 at hydrothermal vein deposits). Additionally, hydrothermal vein deposits could be reclassified into three categories: (1) paste pH>7.0, (2) 4.0

• Economic and Environmental Geology
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• v.45 no.3
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• pp.255-264
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• 2012

The stabilization using limestone ($CaCO_3$) and steel making slag as the immobilization amendments for Cu and Pb contaminated farmland soils was investigated by batch tests, continuous column experiments and the pilot scale feasibility study with 4 testing grounds at the contaminated site. From the results of batch experiment, the amendment with the mixture of 3% of limestone and 2% of steel making slag reduced more than 85% of Cu and Pb compared with the soil without amendment. The acryl column (1 m in length and 15 cm in diameter) equipped with valves, tubes and a sprinkler was used for the continuous column experiments. Without the amendment, the Pb concentration of the leachate from the column maintained higher than 0.1 mg/L (groundwater tolerance limit). However, the amendment with 3% limestone and 2% steel making slag reduced more than 60% of Pb leaching concentration within 1 year and the Pb concentration of leachate maintained below 0.04 mg/L. For the testing ground without the amendment, the Pb and Cu concentrations of soil water after 60 days incubation were 0.38 mg/L and 0.69 mg/l, respectively, suggesting that the continuous leaching of Cu and Pb may occur from the site. For the testing ground amended with mixture of 3% of limestone + 2% of steel making slag, no water soluble Pb and Cu were detected after 20 days incubation. For all testing grounds, the ratio of Pb and Cu transfer to plant showed as following: root > leaves(including stem) > rice grain. The amendment with limestone and steel making slag reduced more than 75% Pb and Cu transfer to plant comparing with no amendment. The results of this study showed that the amendment with mixture of limestone and steel making slag decreases not only the leaching of heavy metals but also the plant transfer from the soil.

• Journal of Bio-Environment Control
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• v.22 no.4
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• pp.366-370
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• 2013

The effects of the early tree shapes with renewal by top-working on Y-shaped peach tree, and the influence on the maintaining fruit quantity with gradual renewal of interstock cultivar were determined. In the comparison of the places of top-working tree, top working tree on the inside of the main branch of interstock cultivar had higher graft union rate and branch growth than those of top working tree on the outside. Tree width, basal diameter of shoot, and number of bearing shoots were smaller in top working tree than in replanted tree. Although labor time was not different to control top working tree and replanted tree, labor time was much required to manage top working tree with interstock cultivar. Accumulated fruit production was 2,384 kg/10a in top working tree and 2,025 kg/10a in replanted tree for three years. However, top working tree had no loss of fruits because interstock cultivar of top-working tree had 3,727 kg/10a of fruits. No variation on fruit quality was observed between top working tree and replanting tree. In terms of economic value of top-working tree, labor to manage interstock cultivar, fertilizer price, fruit bagging, and grading and packing price increased. However, fruit production increased, and price of seedling, rental equipment, pulling-out trees, and repairing supporting system decreased. Therefore, gradual renewal of topworking tree has effects on the maintaining fruit quantity, supplementation on fruit loss, and renewal cultivar.

• Economic and Environmental Geology
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• v.52 no.6
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• pp.627-635
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• 2019

Cement-asbestos slate is the main asbestos containing material. It is a product made by combining 10~20% of asbestos and cement components. Man- and weathering-induced degradation of the cement-asbestos slates makes them a source of dispersion of asbestos fibres and represents a priority cause of concern. When the asbestos enters the human body, it causes cellular damage or deformation, and is not discharged well in vitro, and has been proven to cause diseases such as lung cancer, asbestos, malignant mesothelioma and pleural thickening. The International Agency for Research on Cancer (IARC) has designated asbestos as a group 1 carcinogen. Currently, most of these slats are disposed in a designated landfill, but the landfill capacity is approaching its limit, and there is a potential risk of exposure to the external environment even if it is land-filled. Therefore, this study aimed to exam the possibility of detoxification of asbestos-containing slate by using exothermic reaction and heat treatment. Cement-asbestos slate from the asbestos removal site was used for this experiment. Exothermic catalysts such as calcium chloride(CaCl₂), magnesium chloride(MgCl₂), sodium hydroxide(NaOH), sodium silicate(Na₂SiO₃), kaolin[Al₂Si₂O₅(OH)₄)], and talc[Mg₃Si₄O₁₀(OH)₂] were used. Six catalysts were applied to the cement-asbestos slate, respectively and then analyzed using TG-DTA. Based on the TG-DTA results, the heat treatment temperature for cement-asbestos slate transformation was determined at 750℃. XRD, SEM-EDS and TEM-EDS analyses were performed on the samples after the six catalysts applied to the slate and heat-treated at 750℃ for 2 hours. It was confirmed that chrysotile[Mg₃Si₂O₅(OH₅)] in the cement-asbestos slate was transformed into forsterite (Mg₂SiO₄) by catalysts and heat treatment. In addition, the change in the shape of minerals was observed by applying a physical force to the slate and the heat treated slate after coating catalysts. As a result, the chrysotile in the cement-asbestos slate maintained fibrous form, but the cement-asbestos slate after heat treatment of applying catalyst was broken into non-fibrous form. Therefore, this study shows the possibility to safely verify the complete transformation of asbestos minerals in this catalyst- and temperature-induced process.