• Maxillofacial Plastic and Reconstructive Surgery
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• v.39
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• pp.21.1-21.6
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• 2017

Background: The purposes of the present study were to compare implant stabilities of mandibular block bone graft and bovine bone graft and to evaluate influencing factors for implant stability in mandibular block bone (MBB) graft. Methods: This retrospective study investigated 1224 cases and 389 patients treated by one surgeon in the Department of Oral and Maxillofacial Surgery of Pusan National University Dental Hospital (Yangsan, Korea) between January 2010 and December 2014. Proportions that MBB graft cases constitute in all implant restoration cases and in all bone graft cases were measured. Implant stability quotient (ISQ) values were achieved by the same surgeon before loading. The average ISQ values of the experimental groups were compared. In addition, ISQ values of influencing factors, such as age, sex, implant size, and implant placement site, were compared within the MBB group using $Osstell^{TM}$ Mentor ($Osstell^{(R)}$, $G{\ddot{o}}teborg$, Sweden). Paired t test and ANOVA were conducted for statistical analysis with a significance level of 0.05. Results: Fifty-five percent of all implant restoration cases performed bone graft while MBB cases constituted 34% of all implant restoration cases and 61% of all bone graft cases. Comparing ISQ values according to bone graft materials, the MBB group manifested sufficient implant stability by presenting comparable ISQ value to that of the experimental group without bone graft. Among the reviewed factors, females, mandibular molar regions, and implants in larger diameter displayed greater implant stabilities. Conclusions: Satisfactory implant stability was accomplished upon administration of MBB graft. Within the limitation of this study, gender, implant site, and implant diameter were speculated to influence on implant stability in MBB graft.

• The Korean Journal of Ecology
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• v.21 no.5_3
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• pp.589-602
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• 1998

Mt. Nam (265m), a city park of Seoul, was originally covered with a typical deciduous broad-leaved forests in Central Korea. However, the park forests have been changed the development for various purpose such as the construction of castle wall, road way, broadcasting station, theater, hotel and apartments, in addition, to thoughtless plantation or alien plant introduction. Human population growth from ca. 100 thousands persons less in that time established Seoul as the capital of choseon dynasty in 1394 to ten millions over persons at present, accelerated the vegetational changes of the park. mt. Nam boundary in those days of sunjong (1908) also was much shrinked as much the range of 300 m distance in the northern most to 700 or 800m distance in some places. The actual vegetation of Mt. Nam largely can be classified by floristic composition into two plant communities of Quercus mongolica community and Pinus densiflora community, four plantations of Pinus rigida, Robinia pseudo-acacia, Populus tomentiglandulosa and other tree species, and on mixed forest with native and alien tree species in secondary succession stage (Yim et al. 1987). The restoration movement of Mt. Nam toward to the natural condition of forest or biodiversity is moving now. However, in the movement there are some problems such as the lack of ecological consideration and the undesirable decision of priority in the practice. A warning should be given, especially, on the undesirable plantation of non-native tree species restricting the forest succession, as in the case of southern slope of Mt. Nam. First of all, the most importance in Mt. Nam management is that the restoration for natural forest and biodiversity should be carried on the basis of integrated ecological principles based on the site evaluation.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.7 no.4
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• pp.32-43
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• 2004

Targeting a rooftop biotope created in urban area, this study aims at verifying a creation technique reflecting an urban biosphere reserve concept as well as its function as the habitats of various wild animals. To this end, a set of processes of a biosphere reserve-based basic conception and master plan, sectoral plans, construction and monitoring were applied to the rooftop of 12-story UNESCO Building in Seoul. In particular, the rooftop habitats were divided into core area, buffer zone and transition area, and habitats and facilities suitable to the characteristics of each space were planned. By aligning a plantation planning map with environmental conditions such as topography and water, creation of diverse habitats was enabled. As a result, a set of various habitats including wetlands, wild grassland, shrubs, forest trees and vegetable fields was created at the site. Species living in these habitats included 148 plant species, 62 insect species, 2 amphibian species, 3 fishery species and 3 bird species. The rooftop eco-park of UNESCO Building, which was created one year ago, is assessed as an important space for conservation of biodiversity as well as a place where a biosphere reserve concept was well applied. Meanwhile, for this rooftop biotope to be a pioneer of urban biosphere reserve-based types, a number of principles & methodologies suggested in this study need to be applied, In a perspective of landscape ecology, maintenance efforts should be linked with green areas in neighboring areas, which are the sources of species, In addition, considering that the rooftop biotope is a restored ecosystem, theories and approaches from restoration ecology should be applied. On-going monitoring on environmental changes is also required as the site is located in the urban center, Ultimately, rooftop biotopes including the case study area should contribute in promoting the socio-economic, cultural, and spiritual sustainability as well as environmental sustainability of a city.

• Journal of the Korean Institute of Landscape Architecture
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• v.34 no.1 s.114
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• pp.107-119
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• 2006

The Korea Water Resources Corporation(KOWACO) proposed bidding for an alternative design for Hwabuk Multi-purpose Dam in March of 2004. The site is located in Hakseong-ri, Goro-myeon, Gunwi-gun, Gyeongsangbuk-do and has adrainage area of $87.52km^2$. The purpose of this project is to establish an environmentally friendly plan for minimizing the damage that was caused by the construction of the Hwabuk Multi-purpose Dam. The design principle of KOWACO was the restoration of the natural environment, a harmonious landscape, and the creation of a space of regional and local culture. The basic concept of this project involves an ecological-restoration axis and a functional-connection axis. The site is divided into four spaces: (1) the space of memory and symbol, (2) the space of nature and ecology, (3) the space of regional and local culture, and (4) the space of the regional economy. There are four sub-spaces in the space of memory and symbol: the track forest, the time forest, the memory room, and the sun plaza. There are three sub-spaces in the space of nature and ecology: the habitat of aquatic birds, the wind forest, and the eco-corridor. There are five themed parks in the space of regional and local culture: the culture and relic room, the wildflower garden, the ecological pond, the insect observation park, and the pyogo maze. There are three areas in the space of the regional economy: the forest pension, the waterside pension, and the community center, as Dungdungi village was reorganized to serve as a lodging complex. These themed parks, working together, can offer an effective space for nature, culture, rest, and experience.

• Journal of Wetlands Research
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• v.10 no.2
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• pp.165-172
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• 2008

In order to clarify the factors that diminish the population size of Scirpus planicumis in Han River Esturay Wetland Conservation Area of South Korea, I analysed the autoecological traits of competitive hydrophytes over the species, compared the performance ability of Scirpus planicum group inhabited between in soil-accumulated site and in soil-unaccumulated site, and suggested the management strategy of restoration of this plant based on the field survey. Scirpus planicumis had lower competitive ability than other hydrophyte such as Phragmites australis, Zonia latifolia, Typha augustifola. in terms of dry matter production, height, and reproductive regime. S. planicumis group in soil-accumulated site had lower tuber production, lower vegetative and reproductive production than that of in soil-unaccumulated site, and plant height was shorter in soil-accumulated than in soil-unaccumulated condition. Tuber was appeared in lower soil depth within 15cm in laboratory condition. These results indicated that soil-accumulated condition is the dominant factor caused the decreasing of population size of S. planicumis. It was urgently suggested that constructing a water ways to removed accumulated soil layer is need to restore the population size of S. planiculmus in this wetland.

• The Korean Journal of Ecology
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• v.24 no.2
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• pp.101-109
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• 2001

We created an environmental forest on the basis of ecological design around the incineration plant of Jindo Engineering and Construction Co., Ltd., which is located in Jeongwang-dong, Siheung-si, Kyunggi-do. To get ecological information of this site, physico-chemical properties of soil on salt marsh, which is located close to the syudy site and of forest soil transported from other sites for ecological restoration were analyzed. Texture of salt marsh and transported soils were loam and sandy loam, respectively. pH, organic matter, T-N, available P, and exchangeable K and Na contents of salt marsh and transported forest soils were 6.7 and 5.4, 4.1 and 0.4%, 1.0 and 0.3mg/g, 46.7 and 6.8ppm, 521 and 207ppm, and 3.8 and 0.5mg/g, respectively. Introduced plants were selected among the dominant species of forests and the species composing the potential natural vegetation around the present study site. Those plants were selected again by considering the tolerances to air pollution and to salt, and their availability. Selected trees were Pinus thunbergii, Sophora japonica, Celtis sinensis, Quercus aliena, Q. serrata, Q. dentata, and Q. acutissima. Selected sub-trees were Albizzia julibrissin, Koelreuteria poniculata, and Styrax japonica and shrubs were Rhododendron yedoense var. poukhanense, R. mucronulatum, Callicarpa japonica, Euonymus alatus, E. japonica, and R. schlippenbachii. On the other hand, introduction of herbs was not considered except for Liriope platyphylla, which was ornamentally planted in one site. Planting bed of mound type was adopted to provide the fine drainage system. Mound was designed to furnish litter, A, B, and C layers simuating the profile of forest soil. Slope of mound was mulched by rice straw of 2cm in thickness to prevent for sliding of litter and soil in cases of strong wind or heavy rain. Height of mound was designed to secure more than 1 m by combining A and B layers. Narrow zones, in which mound with stable slope degree cannot be prepared, was designed to equip the standard soil depth with the introduction of stone for supporting. On the other hand, plants with shallow root system were arranged in some zones, in which satisfactory soil depth cannot be ensured. Plants were arranged in the order of tree, sub-tree, and shrub from center to edge on the mound to make a mature forest of a dome shape in the future. Dispersion of plants was designed to be random pattern rather than clumped one. Problems on creation of the environmental forest by such ecological design were found to be management or inspection by non-specialized project operators and inspecting officers, and regulations for construction without ecological background. Alternative plans to solve such problems were suggested.

• Journal of Conservation Science
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• v.37 no.5
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• pp.567-578
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• 2021

In this study, the physicochemical properties of 21 wall fragments and rooftile pieces excavated from Jeseoksa Dump-site were analyzed, and the possibility of heat exposure, such as the fire reported in the literature, was investigated by estimating the firing temperature. From the results, it was estimated that the rooftiles were composed of refined materials, and the walls were composed of materials having different particle sizes depending on the layer. Unlike ordinary rooftiles and walls, they exhibited an uneven surface with traces of bloating phenomenon in the cross section. It was estimated from the blackening of some portions that firing was not performed in a controlled state in a constant firing environment. In addition, the estimated firing temperature showed that the non-overfired rooftiles had endured a firing temperature of 900℃ or less, but the over-fired samples were subjected to a temperature of 1,000℃ or higher and were fired at a temperature higher than the manufacturing temperature at that time. Additionally, the rooftiles probably became defective during firing or molding at the time of production, but the non-overfired rooftiles exhibited an intact shape and showed the possibility of heat exposure due to fire. Therefore, the analytical results of this study confirm that the defective architectural components damaged by the fire, as reported in the literature, were discarded in the Jeseoksa dump-site.

• Restorative Dentistry and Endodontics
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• v.30 no.2
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• pp.112-120
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• 2005

This study was done to evaluate whether there were any differences in microleakage of class V composite restorations according to restoration site and cavity size. Total sixty-four restorations were made in molar teeth using Esthet-X. Small ($2\;{\times}\;2\;{\times}\;1.5\;mm$) and large ($4{\times}2{\times}1.5\;mm$) restorations were made at the buccal/lingual surface and the proximal surface each. After 1,000 times of thermocycling ($5^{\circ}\;-\;55^{\circ}C$), resin replica was made and the percentage of marginal gap to the whole periphery of the restoration was estimated from SEM evaluation. Thermocycled tooth was dye penetrated with $50\%$ silver nitrate solution. After imbedding in an auto-curing resin, it was serially ground with a thickness of 0.25 mm. Volumetric microleakage was estimated after reconstructing three dimensionally. Two-way ANOVA and independent T-test for dye volume, Mann-Whitney U test for the percentage of marginal gap, Spearman's rho test for the relationship between two techniques were used, The results were as follows : 1. The site and size of the restoration affected on the microleakage of restoration. Namely, much more leakage was seen in the proximal and the large restorations rather than the buccal/lingual and the small restorations. 2. Close relationship was found between two techniques (Correlation coefficient = 0.614/ P = 0.000). Within the limits of this study, it was noted that proximal and the large restorations leaked more than buccal/lingual and the small restorations. Therefore, it should be strictly recommended large exposure of margins should be avoided by reducing unnecessary tooth reduction.

• Journal of Ecology and Environment
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• v.33 no.2
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• pp.157-164
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• 2010

We evaluated the restoration effect by introducing willows as a means of controlling invasions of giant ragweed (Ambrosia trifida L.) on a riparian site. Our preliminary survey demonstrated that a problematic exotic species, giant ragweed and the representative riparian species, Salix koreensis are in competitive exclusive relationship. We planted willows at 1 m intervals on the bank of the Dongmun stream at Munsan, Paju, in Central Western Korea as an experimental restoration practice. We installed two 50 m $\times$ 5 m sized restored and non-restored for this experimental study. The non-restored plots were located on river banks, which were covered with concrete blocks and left in itself without any treatment. The height of willow was measured after each of three consecutive growing seasons and compared with the height of the giant ragweed. Although the height of Salix gracilistyla did not achieve the height of the giant ragweed, the height of S. koreensis surpassed that of giant ragweed in the third year after introduction. The results were also reflected in the relative light intensity on the herb layer of willow stand, and thereby the relative light intensities of stands, which were dominated by S. koreensis or restored by introducing S. koreensis, 1.99 $\pm$ 0.33 (%, mean $\pm$ SD) and 1.92 $\pm$ 0.50 (%, mean $\pm$ SD), respectively were lower than those in the stands treated by S. gracilistyla, 3.01 $\pm$ 0.43 (%, mean $\pm$ SD). The giant ragweed stands receive full sunlight as there are no any vegetation layers higher than the herb layer formed by the giant ragweed. As the result of Detrended Correspondence analysis ordination based on naturally established vegetation, the stands dominated by willows and giant ragweed showed different species composition between both stands. The species composition of the restoratively treated sites resembled the reference sites more than the non-treated sites. The species diversity (H') of the sites restored by introducing S. koreensis and S. gracilistyla was higher than the non-restored site dominated by A. trifida. On the basis of our results, the restoration of riparian vegetation equipped with integrated features could contribute not only to the control of exotic plants including giant ragweed but also to ensure the diversity and stability of riverine ecosystems.

• Journal of Environmental Impact Assessment
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• v.28 no.1
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• pp.71-81
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• 2019

This study aims to provide basic data for the decision-making process in selecting sites for wetland restoration projects. To this end, the current list of demaged wetlands was identified based on the findings from the nationwide monitoring project in 2016 targeted at wetlands in inland areas. Then, to determine the necessity of restoration for these demaged sites, the cause of demage was investigated, and their conservation value was examined from an ecological and legal perspective. The 2016 monitoring project identified a total of 20 demaged wetlands, of which one site was deemed to have high conservation value through analysis of its ecological and legal values and on-site reviews. The results of this study are expected to support policymakers' decision-making in selecting wetlands for restoration projects since it identifies priority sites among demaged wetlands that require immediate restoration efforts. It should also be pointed out that wetlands in South Korea cannot benefit from legal protection despite their high conservation value unless they have a designated status as protected areas.