• Ecology and Resilient Infrastructure
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• v.7 no.3
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• pp.208-217
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• 2020

A biopolymer based on microorganism-derived β-glucan and xanthan gum is being studied as a new eco-friendly material that stabilizes the riverbank slope, and also promotes vegetation growth. However, it is still inconclusive whether biopolymers have a positive effect on plant performance in the riverbanks which are subjected to various climatic factors and plant competitions. For a practical ecological evaluation of the biopolymers, their effect on plant growth promotion was studied in a natural environment. Considering the relationship between competition and plant community formation, the effects of biopolymers on competition were also investigated. For four plant species (Echinochloa crus-galli, Pennisetum alopecuroides, Leonurus japonicus, and Coreopsis lanceolata), the biopolymer effects under intra/interspecific competition were tested at the riverbank (20 m × 10 m) near Samjigyo Bridge in Damyang-gun, Jeollanam-do. A biopolymer powder was mixed with water and commercial soil following the manufacturer's recommendations. The soil mixed with the biopolymer was filled in a pot or applied to the surface of the commercial soil with a thickness of 3 cm. Across the competition treatments, the biopolymer treatment promoted root growth of the target plant species and decreased the specific leaf area. The total biomass and shoot dry weight of P. alopecuroides increased in response to the biopolymer treatment. The competition treatment decreased the total biomass and shoot dry weight compared to the case without competition. Notably, such a competitive effect was similar in all the biopolymer treatments. Thus, biopolymers, when mixed with soil, promote the growth of some plant species, but do not appear to affect the competitive ability of plants.

• Ecology and Resilient Infrastructure
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• v.3 no.4
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• pp.221-230
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• 2016

Multi-functional floating wetland island (mFWI) was developed in order to prevent algal bloom and to improve water quality through several unit purification processes. A test bed was applied in the stagnant watershed in an urban area, from the summer to the winter season. For the advanced treatment, an artificial phosphorus adsorption/filtration medium was applied with micro-bubble generation, as well as water plants for nutrient removal. It appeared that the efficiency of chemical oxygen demand (COD) and total phosphorus (T-P) removal was higher in the warmer season (40.9%, 45.7%) than in the winter (15.9%, 20.0%), and the removal performance (suspended solid, chlorophyll a) in each process differs according to seasonal variation; micro-bubble performed better (33.1%, 39.2%) in the summer, and the P adsorption/filtration and water plants performed better (76.5%, 59.5%) in the winter season. From the results, it was understood that the mFWI performance was dependent upon the pollutant loads in different seasons and unit processes, and thus it requires continuous monitoring under various conditions to evaluate the functions. In addition, micro-bubbles helped prevent the formation of anaerobic zones in the lower part of the floating wetland. This resulted in the water circulation to form a new healthy aquatic ecosystem in the surrounding environment, which confirmed the positive influence of mFWI.

• Ecology and Resilient Infrastructure
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• v.5 no.2
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• pp.105-109
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• 2018

The main objective of this investigation was to examine oxygen consumption and ammonia excretion within cultured catfish, Silurus asotus ($22.9{\pm}0.9cm$, $100.7{\pm}11.7g$ n = 30) by noise and vibration stress in aquaculture farm. The vibration of 48, 58 and 68 dB (V) and noise of $77.6{\pm}1.8dB$ (A) from an electric vibrator was turned on for 15 minutes during each hour each day(0800-1800) for 11 days experimental period. The oxygen consumption (OC) of S. asotus the beginning of the experiment (0 day) in 58 dB group after 1, 5, 9 and 11 days was decreased 21.8, 30.2, 36.0 and 53.2%, respectively. In 68 group after 1, 7 and 11 days was decreased 22.7, 35.1 and 57.7%, respectively. The OC decreased exponentially and the relationship between them was expressed as OC = 0.374D + 90.762 ($r^2=0.048$) at 48 dB, OC = -3.581D + 89.520 ($r^2=0.831$) at 58 dB and OC = -4.109D + 90.907 ($r^2=0.884$) at 68 dB. Ammonia excretion (AE) of the beginning of the experiment in 48, 58 and 68 groups after 1 day was increased by 34.8, 51.8 and 63.2%, respectively, but it was decreased significantly from 3 to 11 days. The AE increased exponentially and the relationship between them was expressed as AE = -1.646D + 115.915 ($r^2=0.265$) at 48 dB, AE = -8.230D + 122.132 ($r^2=0.750$) at 58 dB and AE = -7.086D + 123.690 ($r^2=0.614$) at 68 dB.

• Ecology and Resilient Infrastructure
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• v.7 no.2
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• pp.126-133
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• 2020

In accordance with the implementation of the sunset provision to cancel the designations of urban park sites that remained unexecuted for a prolonged period until 2020, the park sites in the city center, which account for 90% of the long-term unexecuted urban facilities subjected to the provision, are currently on the verge of development. The total area of the 204 park sites that will disappear in Seoul as a result of this provision is 95 ㎢; moreover, 116 of these are privately-owned. It is expected that the possible changes in the use of these park sites could result in reckless development and reduction of green space, which would ultimately affect the ecosystem. This study applied the InVEST model to calculate the changes in the fixed carbon amount before and after the implementation of the sunset provision to estimate the economic value of these changes. The study focused on Jongno-gu in Seoul because it has the most unexecuted park sites subjected to the lifting of the designation. The research findings show that the fixed carbon amount provided by the unexecuted park sites in Jongno-gu was 374,448 mg, prior to the implementation of the sunset provision; however, the amount was estimated to decrease by 18% to 305,564 mg after its execution. When calculated in terms of average value of the real carbon price, this translated into a loss of approximately 700 million won. In addition, considering the social costs including both climate change and the impact on the ecosystem, an economic loss of approximately 98 billion won was projected. This study is meaningful because its predictions are based on the estimation of fixed carbon amount according to the implementation of the sunset provision in Jongno-gu and scientifically calculates the value of ecological services provided by the parks in the city. This study can serve not only as a basis during the decision-making process for policies related to ecosystem conservation and development, but also as an evidentiary material for the compensation of privately-owned land that is designated as urban park sites and was unexecuted for a prolonged period.

• Ecology and Resilient Infrastructure
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• v.6 no.4
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• pp.200-207
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• 2019

The movement distance and home range size of Pelophylax chosenicus were identified in the rice paddy and ecological park as alternative habitats from July to November 2017. A total of 39 frogs were tracked by radio tracking method. As a result, the average move distance in the population of rice paddy was 11.7 ± 1.9 m (n = 64) and the population of ecological park was 24.7 ± 4.3 m (n = 39). The move distance between the two populations was significantly different. The mean MCP of the population of rice paddy was 181.2 ± 110.8 m² (n = 11) and the population of ecological park was 416.1 ± 276.2 m² (n = 10), but there was no significant difference. The population area of rice paddy was 4,160 m² (Kernel density 95%) and the core area was 1,080 m² (Kernel density 50%). The population area (Kernel density 95%) of ecological park was 5,391 m² and the core area (Kernel density 50%) was 736 m². This study shows that it is appropriate to construct the area of alternative habitat for P. chosenicus at least 1.33 ha, and it is more advantageous for the ecological park to be constructed than the paddy field with high development pressure and human interference. If the rice paddies were to be abandoned for several years, or to be used traditional farming methods, such as refraining from using agricultural machinery and chemicals, they could be used as alternative habitat for P. chosenicus.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.4
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• pp.325-335
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• 2008

The junction between resilient denture liner and the denture base is difficult to finish and polish due to difference of the physical property of the materials. Gaps tend to be formed during finishing and polishing procedures. The purpose of this study was measuring the width of junctional gap between $Molloplast-B^{(R)}$ and denture base material after finishing and polishing procedure, and evaluating the effect of method and direction on gap width. $Molloplast-B^{(R)}$ was processed (according to the manufacturer's instruction) against Lucitone $199^{(R)}$ acrylic resin. 50 specimens were fabricated with a raised center section. All of specimens were examined and photographed with a stereoscopic microscope(x120), and the largest gap along the junction of $Molloplast-B^{(R)}$ and acrylic resin on each specimen was measured. One-way analysis of variance(ANOVA) and independent t-test at 95% confidence level were used to analyze the data and to compare groups. The results of this study were as follows. In comparison with finishing tools, the gap width was the largest in $Molloplast^{(R)}$-Cutter and the smallest in FSQ-cross cut bur. There was statistically significant difference between FSQ-cross cut bur and $Molloplast^{(R)}$-Cutter(p<0.05). There was no significant difference in gap width between the direction of polishing. The mean value of gap width was the smallest in case of no polishing, and the largest in case of polishing with pumice & tin oxide. There was statistically significant difference between pumice and pumice & tin oxide. From the results, it is concluded that the use of $Molloplast^{(R)}$-Cutter in clinic need serious consideration even though it has good cutting ability. Further careful study is needed for finishing and polishing methods for decreasing gap width in junction of two materials.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.13 no.3
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• pp.226-234
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• 2020

As the average life expectancy of human beings is extended in addition to the entry of the aging society, there is a tendency for the interest in the appearance of men and women in modern society to increase. The most external judgment of human aging is the wrinkles on the facial skin. People are undergoing various procedures to have clean, wrinkled, and resilient healthy skin. Many thread lifting procedures are being implemented because they tend to want simple and effective procedures during the procedure. In this study, in order to improve lifting effect in thread lifting, animal experiments were conducted to confirm the improvement of wrinkles by injecting RF high frequency and CO₂ gas into existing PDO suture procedures. The experimental groups consisted of natural aging groups, PDO treatment groups, groups with RF high frequency in PDO procedures, groups with CO₂ gas injected into PDO procedures, and groups with CO₂ gas and RF injected simultaneously into PDO procedures. The individuals in the natural aging group had an average wrinkle depth of 0.408mm before the procedure, and the average wrinkle depth of the 10th week was 0.68mm. The depth of wrinkles in the PDO treatment group averaged 0.384mm before the procedure, and 0.348mm on the 10th week after the procedure. The average crease depth of pre-procedure objects injected with RF high frequency in PDO was 0.42mm, and the average crease depth for 10 weeks was 0.378mm. The average crease depth of the CO₂ gas injected into the PDO was 0.4mm before the procedure, and the average crease depth was reduced to 0.332mm in the 10th week after the procedure. On average, the number of objects injected with CO₂ gas and RF high frequency in the PDO procedure decreased to 0.412mm before and 0.338mm in the 10th week after the procedure. The procedure of injecting CO₂ gas and RF into the PDO suture showed the highest reduction rate of 17.96%.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.223-232
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• 2021

In general, stormwater flows to the road surface, especially in urban areas, and it is discharged through the drainage grate inlets on roads. The appropriate evaluation of the road drainage capacity is essential not only in the design of roads and inlets but also in the design of sewer systems. However, the method of road surface flow analysis that reflects the topographical and hydraulic conditions might not be fully developed. Therefore, the enhanced method of road surface flow analysis should be presented by investigating the existing analysis method such as the flow analysis module (uniform; varied) and the flow travel time (critical; fixed). In this study, the algorithm based on varied and uniform flow analysis was developed to analyze the flow pattern of road surface. The numerical analysis applied the uniform and varied flow analysis module and travel time as parameters were conducted to estimate the characteristics of rainfall-runoff in various road conditions using the developed algorithm. The width of the road (two-lane (6 m)) and the slope of the road (longitudinal slope of road 1 - 10%, transverse slope of road 2%, and transverse slope of gutter 2 - 10%) was considered. In addition, the flow of the road surface is collected from the gutter along the road slope and drained through the gutter in the downstream part, and the width of the gutter was selected to be 0.5 m. The simulation results were revealed that the runoff characteristics were affected by the road slope conditions, and it was found that the varied flow analysis module adequately reflected the gutter flow which is changed along the downstream caused by collecting of road surface flow at the gutter. The varied flow analysis module simulated 11.80% longer flow travel time on average (max. 23.66%) and 4.73% larger total road surface discharge on average (max. 9.50%) than the uniform flow analysis module. In order to accurately estimate the amount of runoff from the road, it was appropriate to perform flow analysis by applying the critical duration and the varied flow analysis module. The developed algorithm was expected to be able to be used in the design of road drainage because it was accurately simulated the runoff characteristics on the road surface.

• Ecology and Resilient Infrastructure
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• v.8 no.4
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• pp.290-298
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• 2021

This study was conducted to evaluate the possibility of applying phytoremediation technology by investigating soil and native plants in waste coal landfills exposed to heavy metal contamination for a long period of time. The ability of native plants to accumulate heavy metals using greenhouse cultivation experiments was alse evaluated. Plants were investigated at an abandoned coal mine in Hwajeolyeong, Jeongseon, Gangwon-do. Two species of native plants (Carex breviculmis. R. B. and Salix koriyanagi Kimura ex Goerz.) located in the study area and three Korean native plants (Artemisia japonica Thunb. Hemerocallis hakuunensis Nakai., and Saussurea pulchella (Fisch.) Fisch.) were cultivated in a greenhouse for 12 weeks in artificially contaminated soil. Soils contaminated with arsenic and lead were generated with arsenic concentration gradients of 25, 62.5, 125, and 250 mg kg^-1 and lead concentration gradients of 200, 500, 1000, and 2000 mg kg^-1, respectively. Results showed that none of the five plants could survive at high arsenic concentration treatment (125 and 250 mg kg^-1) and some plants died in 2000 mg kg^-1 lead concentration treatment soil. The plant translocation factor (TF) was highest in H. hakuunensis in arsenic treatments, and A. japonica in lead treatments, respectively. The bioaccumulation factor (BF) of plants was more than 1 in all species in arsenic treatment, whereas it was highest in H. hakuunensis. BF for all species was less than 1 in lead treatment. Particularly, in 2000 mg kg^-1 concentration lead treatment, A. japonica accumulated more than 1000 mg kg^-1 lead and was expected to be a lead hyperaccumulator. In conclusion, A. japonica and H. hakuunensis were excellent in the accumulation of arsenic heavy metals, and S. koriyanagi was excellent in lead accumulation ability. Therefore, the above mentioned three plants are considered to be strong contenders for application of the phytoremediation technology.

• Ecology and Resilient Infrastructure
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• v.8 no.2
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• pp.120-132
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• 2021

The ecosystem and landscape conservation areas of Seoul were designated according to the Natural Environment Conservation Act and the Natural Environment Conservation Ordinance. With the adoption of the "Rapid Assessment of Wetland Ecosystem Service (RAWES)" approach and the "wetland ecosystem service" for the Ramsar Wetland City Accreditation at the 13th Meeting of the Conference of the Contracting Parties to the Ramsar Convention on Wetlands in 2018, the need for data evaluating wetland ecosystem services has become a necessity. Therefore, in this study, we selected five wetlands from the ecosystem and landscape conservation areas in Seoul, having high ecological conservation values, and evaluated their carbon sequestration and economic value assessment using the InVEST model, which is an ecosystem service evaluation technique. The evaluation results for carbon storage in each wetland are as follows: Tancheon Wetland: 3,674.62 Mg; Bamseom Island in the Hangang River: 1,511.57 Mg; Godeok-dong Wetland: 5,007.21 Mg; Amsa-dong Wetland: 7,108.47 Mg; and Yeouido Wetland: 290.27 Mg. Particularly, the Tancheon Wetland showed the lowest carbon sequestration of 1,130.37 Mg, as compared to the results acquired in 2013, of 4,804.99 Mg. When the average effective carbon rate of $16.06 (US) was applied to the decreased carbon sequestration value, a loss of $15,910.58(US) was calculated. Furthermore, if the average social cost of carbon ($204 (US)) is considered, which includes the impact of climate change on productivity and ecosystems, the total loss is equivalent to $202,101.97 (US). This study aims to examine the natural resource value of urban wetlands by evaluating selected major wetlands in Seoul. This study can be utilized as basic data to plan for the protection and management of the ecosystem and landscape conservation areas. Additionally, because wetland value assessment is considered essential, the results of this study can be used in future research to provide measures for evaluating ecosystem services in the Ramsar Wetland City Certification System. Moreover, this study can be utilized for selecting important wetlands as Ramsar sites, and to raise awareness about the significance of conserving urban wetlands, and for expanding international exchange among the Ramsar Wetland sites.