• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.34 no.2
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• pp.115-124
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• 2024

Objectives: The aim of this study is to assess indoor air quality within and around buildings and evaluate the health risks associated with exposure to indoor air pollution. The study compares IAQ standards established by the World Health Organization with those set by South Korea's Ministry of Environment and Ministry of Education. Methods: The study utilized an Anderson Sampler and DustTrak^TM II to collect samples of total airborne bacteria and PM in indoor and outdoor environments. Collected samples were analyzed using biological and biochemical methods. Statistical analysis was conducted using SPSS to examine the correlation between airborne bacteria and PM. Results: The study revealed that the concentration of total airborne bacteria in indoor air generally remained below the Ministry of Environment's standard of 800 CFU/m³, although it surpassed this threshold in certain instances. PM concentrations did not exceed the standards. Indoor fine dust concentration was higher when there were people (P<0.05). There was no difference in total floating bacterial concentrations between indoor and outdoor environments (P=0.184). Finally, there was a correlation between fine dust and airborne bacteria concentrations. Conclusion: The study evaluated the concentrations of total airborne bacteria and PM in indoor air, emphasizing the importance of managing IAQ. Further research in various environments is essential to ensure a healthy indoor environment. The findings underscore the need for ongoing research and management to enhance IAQ and create safer and healthier living environments.

• Journal of the Korean Wood Science and Technology
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• v.32 no.5
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• pp.75-85
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• 2004

The natural dyes from Gardenia jasminoides, Carthamus tinctorius L., Rhus javanica, Lithospermum erythrorhizon, Caesalpinia sappan L., and Castanea crenata were extracted under different pH in distilled water, As the pH in distilled water went from acid to alkali, the much deeper colors in the same color tone were generated from the individual plant species. Before dyeing, wood species were treated by different mordants including AI, Cu, Cr and Fe for color-fixing between wood and the natural dyes. Each mordant could develop independent color on the surface of the woods. The wood species dyed by the natural dyes created deep-tone colors according to higher pH and temperature of the dyeing solution, leading to deeper penetration of the dyes into the wood tissues. Finally through the computer modelling of natural-dyed wood furniture, it was confirmed that the colored furniture can adequately be compatible with the current interior spaces of diverse colors.

• Restorative Dentistry and Endodontics
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• v.32 no.1
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• pp.47-60
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• 2007

The purpose of this study is to compare and to evaluate the effect of pH and lactic acid concentration on the progression of artificial root caries lesion using polarizing microscope, and to evaluate the morphological changes of hydroxyapatite crystals of the demineralized area and to investigate the process of demineralization using scanning electron microscope. Artificial root caries lesion was created by dividing specimens into 3 pH groups (pH 4.3, 5.0, 5.5), and each pH group was divided into 3 lactic acid concentration groups (25 mM, 50 mM, 100 mM). Each group was immersed in acid buffer solution for 5 days and examined. The results were as follows : 1. Under polarized microscope, the depth of lesion was more effected by the lactic acid concentration rather than the pH. 2. Under scanning electron microscope, dissolution of hydroxyapatite crystals were increased as the lactic acid concentration increased and the pH decreased. 3. Demineralized hydroxyapatite crystals showed peripheral dissolution and decreased size and number within cluster of hydroxyapatite crystals and widening of intercluster and intercrystal spaces as the pH decreased and the lactic acid concentration increased. 4. Under scanning electron microscope evaluation of the surface zone, clusters of hydroxyapatite crystals were dissolved, and dissolution and reattachment of crystals on the surface of collagen fibrils were observed as the lactic acid concentration increased. 5. Under scanning electron microscope, demineralizatlon of dentin occurred not only independently but also with remineralization simultaneously. In conclusion, the study showed that pH and lactic acid concentration influenced the rate of progression of the lesion in artificial root caries. Demineralization process was progressed from the surface of the cluster of hydroxyapatite crystals and the morphology of hydroxyapatite crystals changed from round or elliptical shape into irregular shape as time elapsed.

• Journal of Animal Science and Technology
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• v.46 no.3
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• pp.443-450
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• 2004

To examine the potentiality of grassland dominated with turf-type grasses, which are mainly used for the establishment of green spaces, forage production and its utilization as forage resources, dry matter yield and forage quality of three different turf-type mixtures were estimated throughout three consecutive experimental years. According to the experiment, the mean of dry matter(DM) yield, chemical composition, DM digestibility, crude protein dry matter(CPDM) and digestible dry matter(DDM) yield was not significantly different among species(p > 0.05) over three experimental years. Botanical composition of three dominant species(tall fescue, Kentucky bluegrass and perennial ryegrass) was 42, 35 and 28%, respectively, in three mixtures at the last cutting(6th) in 2001. The botanical composition of three dominated species such as tall fescue, Kentucky bluegrass and perennial ryegrass was maintained 84% of the total plants in all types of mixtures. Therefore, It is observed that the mixture types did not closely affect the botanical composition. But botanical composition of the other species such as redtop(8%) and creeping bentgrass(6${\sim}$7%) was low. Especially, that of red fescue was the least(1${\sim}$2%) of all mixed species. As mentioned above, any difference was not observed in DM yields, forage quality and botanical composition among mixture types. Therefore, any types of mixtures can be used as public green spaces like school ground areas or river-sides, and as forage resources additionally.

• Korean Journal of Environment and Ecology
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• v.23 no.6
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• pp.553-563
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• 2009

This study was conducted to analyze the changes in the echolocation of Pipistrellus abramus according to environmental characteristics. The survey was conducted in the day-roosting site of P. abramus located in Gyeongju City (North Gyeongsang Province) from April to August, 2009. The environmental characteristics during the research were classified in six categories: the emergence time after sunset moving time from day roost to feeding areas; rice fields; forest edges; open spaces; and residential areas. Analysis results showed that there are differences in environmental characteristics and also differences between the moving time to the habitat and the moving time to capture preys. At the emergence time from day roost, Pipistrellus abramus used a FM signal with a short pulse-duration. In open spaces, however, they used a CF signal with a long pulse-duration. In different environmental situations, they used both FM and CF signals, although the types of pulse which they used were different. Except pulse-duration, there were significant differences in pulse-interval, peak-frequency, starting-frequency and ending-frequency between the movement among habitats and the movement to capture preys. Except the emergence time from day-roost, they showed a narrow band FM signal and a long pulse-duration that are suitable to search for insects by sensing echoes of insects when they moved among their habitats. When they were out to capture their preys, they showed a broad band FM signal and a short pulse-duration which enabled them to widely search and accurately locate their preys.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.06a
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• pp.1-5
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• 2003

In order to prepare a basis for ecological restoration of the Seoul Metropolitan area, ecological diagnoses on soil physico-chemical properties and vegetation structure were carried out. Land use patterns, actual vegetation, and biotope patterns were also investigated based on aerial photograph interpretation and field checks. I formulated landscape elements overlaying those data and evaluated the ecological value of each element. Soil pollution was evaluated by analyzing soil samples collected in each grid on the mesh map, divided by 2km $\times$ 2km intervals. Soil samples were collected in forests or grasslands escaped from direct human interference. Soil pollution evaluated from pH, and SO$_4$, Ca, Mg, and Al contents of soil was more severe in the urban outskirts than in the urban center. Those soil environmental factors showed significant correlation with each other. Vegetation in the urban area was different in species composition from that in suburban areas and showed lower diversity compared with that in the suburban areas. Successional process investigated by population structure of major species also showed a difference. That is, successional trend was normal in suburban areas, but that in urban areas showed a retrogressive pattern. The landscape ecological map of Seoul indicates that the urban center lacks vegetation and greenery space is restricted in urban outskirts. Such an uneven distribution of vegetation has caused a specific urban climate and thereby contributed to aggravation of air and soil pollution, furthermore causing vegetation decline. From this result, it was estimated that such uneven distribution of vegetation functioned as a trigger factor to deteriorate the urban environment. I suggested, therefore, a restoration plan based on landscape ecological principles, which emphasizes connectivity and even distribution of green areas throughout the whole area of the Seoul to solve this complex environmental problem. In this restoration plan, first of all, I decided the priority order for connection of the fragmented greenery spaces based on the distances from the core reserves comprised of green belt and rivers, which play roles as habitats of wildlife as well as for improvement of urban environment. Next, I prepared methods to restore each landscape element included in the paths of green network to be constructed in the future on the bases of such preferential order. Rivers and roads, which hold good connectivity, were chosen as elements to play important roles in constructing green network by linking the fragmented greenery spaces.

• Journal of Animal Environmental Science
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• v.18 no.3
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• pp.157-164
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• 2012

This study was conducted to investigate the effect of different farrowing space, narrow and wide, on the sow performances and piglet growth performances. The $1.5m^2$ of narrow farrowing space was determined as the size of farrowing crate. The $3.0m^2$ of wide space for farrowing sow was the same of farrowing pen to allow the behavior freedom of sow. Baby piglets in the wide farrowing space was protected from crushing of sow by installation of safety bar. The pregnant sows used in this study were stall-housed during gestation and moved to each farrowing spaces on 8 d before parturition. Feed intake, backfat thickness and body condition score of sow were not affected by both farrowing spaces. However, the changes in backfat thickness and body condition score between farrowing and weaning in wide farrowing space were lower (p<0.05) than in narrow farrowing space. The return to estrus of sow was remarkably decreased in wide farrowing space compared to sows in narrow farrowing space. The lower number of stillbirth and higher mortality of piglets were observed in wide farrowing space. From the results, although wide farrowing space could be practically acceptable in terms of sow performances, possible cause of mortality of piglets should be scrutinized through observation of piglet and sow behaviors.

• Journal of the Korean Wood Science and Technology
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• v.38 no.3
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• pp.165-169
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• 2010

The cityward tendency of the population caused the building crowd and the skyscrapers, and destroyed the cityscape and ecosystem of the city. For this reason, many researchers studied to make more green spaces in the city. The roof greening is one of the methods to get the green spaces in the city. There are some problems in this method such as the safety load, growth of the plants on the artificial foundation, and so on. In this study, we evaluated the waste woodchips and the waste papers as a new materials for the artificial foundation. The new artificial foundation was made of the waste woodchips and the waste papers with the different ratio of mixture (woodchips, paper slurry, and fertilizer). The artificial foundation was applied to the planting of three different plants (creeping bentgrass, barley, and wheat). It was found that the growth of the plants with 1% of fertilizer was higher than other conditions. The best making condition of foundation was 40% pulp and 60% woodchips in the germination of all plants.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.2
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• pp.75-86
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• 2004

This study aims to figure out ecological characteristic of natural forests focusing on vegetation as a way of ecological renovation for the restoration of naturalness for golf courses that were constructed in the Country and to present vegetation models and appropriate tree species for the purpose. The study site is P golf club, which is located in Gapyong-gun, Kyeonggi Province. The site is within a forest where the grade from the natural ecology map is the first one and the level from the green index accounts for the eight, thus showing a typical environment for a golf course in terms of location. The location of the site explains a reason for restoration. The major substance of the study is to conduct ecological evaluation of vegetation structures around and inside the golf course and to present a vegetation model. In order to evaluate the ecological characteristics of the vegetation structures, the analysis of the study covered succession stages, multi-layer vegetation structures and species diversity. Plant communities that have high species diversity were selected for the vegetation model and proper density and species were proposed considering the number of species and individuals and distances between trees. The vegetation restoration model targets succession into an oak forest. Within a unit of 100 $m^2$, the recommended model include a tall-tree layer with 11 trees such as Quercus serrata and Quercus mongolica, a sub-tall-tree layer with 12 trees including Quercus mongolica, Quercus serrata, Prunus sargentii, Fraxinus rhynchophylla and Acer pseudo sieboldianum, a shrub layer with 32 trees from 16 species, and a grass layer with a cover rate of 45 %. The proposed vegetation restoration model needs to apply to : 1) damaged natural forests by the construction of golf courses; 2) boundaries between golf courses and surrounding forests; 3) buffer zones; 4) open spaces in between courses; and 5) areas between greens and tees where open spaces are available in a mass. In conclusion, one of the most important factors in presenting a vegetation model for the restoration of naturalness in the golf course and other damaged forests is to provide multi-layer vegetation structures that are composed of native species. As for the specific application for the site, it is recommended to manage the vegetation in such a way that the environment of the site can have a similar environment to the surrounding forest which is expected to succeed into an oaks-dominant one.

• Journal of the Architectural Institute of Korea Planning & Design
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• v.34 no.12
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• pp.65-76
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• 2018

Due to the rapid demographic and structural changes, Korea has faced a variety of social issues and quickly entered the aged society since the 2000s. In order deal with this reality, diverse types of welfare policies are emerging in the society as a whole. The government began to supply domestic public silver housing in 2016 to provide against the quickly growing aged society and now, the government is planning to supply approximately 50,000 housing by 2022 for quantitative growth of aged society, by selecting 1st and 2nd designated areas for the project additionally. This public retirement(silver) housing combines 'space' with 'service'. The lower floors are a public silver welfare Facilities and the upper floors are a housing spaces. This type of housing is to deal with requirements of rental housing residents by combining physical space with supporting service. Based on barrier-free design, the complex and unit house have safety handles and alarm bells in the bathroom, undulating washstands, bathroom sliding doors, corridor safety handles, and emergency safety exit lamps in each housing unit so the aged and the disabled can use easily and conveniently. Also, hand rails are installed and stepped pulleys are removed to promote convenience. Currently, the government is planning to increase the supply, focusing on low-income groups, such as beneficiaries of national basic livelihood and the working poor. Recognizing that the public retirement(silver) housing project is at its early stage, this study examined satisfaction, based on evaluations of real residents. This study aimed to obtain more empirical research data and apply them to public retirement(silver) house space analysis. For analysis, this study targeted Wirye public retirement(silver) housing and Magnolia public retirement(silver) housing that are in operation, and literature review, previous research review, and field survey were conducted to examine the present state. Using the questionnaires consisting of four large classification items; Block Layout, Housing Unit, Welfare Facilities, and Barrier-free Design, and sub-details, a survey was conducted to analyze residents' satisfaction. In conclusion, it is anticipated that this study would serve as basic research data about public retirement(silver) housing to increase continuously in future by analyzing public retirement(silver) housing spaces, on the basis of the analyzed data.