• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.6
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• pp.2211-2221
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• 2013

During the four river restoration project, several weirs were constructed in the four rivers to prevent drought and flood, to improve water quality, and to manage water resources. However, due to the weir construction, bed changes are produced in the upstream channel of installed weirs because the incoming flow velocity is reduced and sediment transport capacity is also lowered. Especially, since the Haman Weir is located in the lowest downstream section among newly installed weirs in Nakdong River, bed change and sedimentation problems are expected due to the mild slope and reduced velocity. Therefore, numerical simulation was performed to analyze flow and bed changes in the upstream channel of Haman Weir and to evaluate quantitatively sediment control methods for bed stabilization using CCHE2D model. As a result of flow and bed change simulation after installation of Haman Weir, the flow velocity at the initial condition was faster than the final bed condition with the specific simulation time and it was represented that the locations where bed changes were great were identical for all modeling conditions of flow discharge. In case of 4.5 m of water level lowered from 5.0 m of the management water level at Haman Weir for bed stabilization, the flow velocity was generally faster than the case of the management water level and the continuous erosion was developed at the most narrow channel section as the applied discharge and simulation period were increased. The channel width extension at the most narrow channel section was proposed in this study to prevent and stabilize continuos bed erosion. As a result of numerical analysis, there was no bed erosion after channel width extension and it was presented that the channel geometry extension was effective for bed stabilization at Haman Weir.

• Korean Journal of Environment and Ecology
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• v.26 no.5
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• pp.741-757
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• 2012

This study had targeted the Seunghwanglim of Wonju in order to understand the forest vegetation's present condition. And then we compared the change in vegetation of Seunghwanglim for 24years. It was intended to provide basic data for conservation and management. Actual vegetation as a result of investigation, a total area of $56,231m^2$ Quercus serrata forest(7.02%), Acer triflorum forest(5.71%), and Deciduous Broad-Leaved Forest and Pinus densiflora forest(6.4%) were distributed variously. Present condition of the plains forest has 34 kinds of canopy species, 65 kinds of understory species, 70 species of shrubs species, 88 species of total species. And the plains forest has 500 individuals of canopy layer, 1,102 individuals of understory layer. Mean importance percentage of the major species showed Ulmus davidiana var. japonica(15.6%), Acer triflorum(15.2%), Pinus densiflora(11.1%), Quercus serrata(9.8%). Acer triflorum diameter at Ulmus davidiana var. japonica were a relatively wide range. Results of change for 24 years, vegetation of Seunghwanglim was changed from Quercus serrata-Acer triflorum to Ulmus davidiana var. japonica-Acer triflorum. Big trees over than DBH 30cm were surveyed total 18 species, 166 individuals. Increased over than the past 63 individuals. Seunghwanglim was destroyed by reckless past. Since 1990, the outer perimeter fence was installed to control human access. After that, understory layer and shrub layer were developed. And big tree was increased. Which is considered to restore damaged ecosystems. In order to conservation and protection of Seunghwanglim, people have to management and monitor about exotic species such as Robinia pseudo-acacia, Populus tomentiglandulosa, Castanea crenata, Pueraria lobata, etc.

• Korean Journal of Environment and Ecology
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• v.28 no.5
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• pp.550-558
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• 2014

This study was conducted to investigate the distribution and the population dynamics of Hipparchia autonoe by using a line transect and Mark-Release-Recapture (MRR) at the Mt. Halla in Jeju Island. The results showed that H. autonoe was found from 1,500 m above the sea level. Total 1,493 H. autonoe with 978 males and 515 females were captured and released in the MRR study site. Among them, 518 individuals including 284 males and 234 females were recaptured. The average survival time was 2.31 days with 2.14 days for males and 3.47 days for females, indicating longer survival time in case of females than males. The daily population size of males estimated in the MRR study site was maintained about 1,000 individuals in July and gradually decreased less than 200 in August. The number of females showed peak at 335 individuals on July 24, and gradually decreased less than 120 in August. Thus, female population was 1/3 of males. The average travel distance of male and female H. autonoe were $116.8{\pm}191.9m$ and $118.4{\pm}161.5m$, respectively, indicating almost same between sexes. H. autonoe in the Mt. Halla formed single population group in the wide meadow around the Baekrokdam Lake. The highest population density of H. autonoe was occurred in the restored area from damages, where host plants such as the sheep's fescue or the food plant are abundant by artificial restoration efforts.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.33 no.2
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• pp.67-77
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• 2015

The purpose of this paper is to draw historic valuable resources to conserve through the analysis about the preservation status of historic urban environment in Suwon Hwaseong Fortress. As for the conservation of urban environment, it is important to protect the resources showing historical continuity and to manage the resources remaining characteristics of place, the analysis of the preservation status is focused on the perspective of preservation of physical form and land use. This paper makes progress through three phases. First, in order to understand urban environment in Hwaseong Fortress overall, it compares land registration original map in 1911 to current map in 2014 by the four items of topography, water environment, streets and sites. Next, changes of four items in urban environment have been reviewed further by the research of maps, relative literatures, field survey and interview, and are classified according to the criteria of preservation-partially preservation-disappearance. After analysing preservation status, valuable urban historic cultural resources are drawn separately by being preserved continually and by being preserved partially but remaining characteristics of place. As a result, natural factors of topography and waterway and urban factor of streets are remained considerably preserved. And even if these factors are changed, the ground environment features support to understand historic urban context. Second, as preservation of topography, water environment, streets and sites are closely related to each other, integrated conservation frameworks are needed to enhance urban historic landscape. Third, modern historic resources in Hwaseong are remained unchanged and thus it is necessary to understand urban historic environment by the layers of various times besides Joseon Dynasty period. Fourth, historic sites and streets which had been preserved through urban development process are destroyed by recent historic cultural restoration policies, therefore urban historic resources worthy of conservation should be treated prudently.

• Journal of Biomedical Engineering Research
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• v.25 no.3
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• pp.171-182
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• 2004

This study investigates the biomechanical efficacies of vertebroplasty which is used to treat vertebral body fracture with bone cement augmentation for osteoporotic patients using image and finite element analysis. Simulated models were divided into two groups: (a) a vertebral body, (b) a functional spinal unit(FSU). For a vertebral body model, the maximum axial displacement was investigated under axial compression to evaluate the effect of structural integrity. The stiffness of each FE model simulated was normalized by the stiffness of intact model. In the case of FSU model, 3 types of compression fractures were formulated to assess the influence on spinal curvature changes. The FSU models were loaded under compressive pressure to calculate the change of spinal curvature. The results according to the various factors suggest that vertebroplasty has the biomechanical efficacy of the increment of structural reinforcement in a patient who has relatively high level of BMD and a patient with the amount of 15％, PMMA injection of the cancellous bone volume. The spinal curvatures after compression fracture simulation vary from 9$^{\circ}$ to 17$^{\circ}$ of kyphosis compared to that the spinal curvature of normal model was -2.8$^{\circ}$ of lordosis. These spinal curvature changes cause the severe spinal deformity under the same loading. As the degree of compressive fracture increases the spinal deformity also increases. The results indicate that vertebroplasty has the increasing effect of the structural integrity regardless of the amount of PMMA or BMD and the restoration of decreased vertebral body height may be an important factor when the compressive fracture caused the significant height loss of vertebral body.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.252-259
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• 2017

Purpose: The purpose of this study was to compare and analyze the wear of a prosthesis for 6 months after restoration with implant-supported fixed dental prosthesis made of either zirconia or gold. Materials and Methods: This study was conducted on patients requiring implant-supported fixed dental prostheses on first or second molar from January, 2015 to January, 2016. A total of 47 prostheses and antagonists were examined. Occlusal surface was recorded by impression of each prosthesis and antagonist 1 week and 6 months after prosthesis delivery. The digital files were created by impression scan. Occlusal shapes of 1 week and 6 months were compared and wear of prostheses and antagonists was analyzed. The Mann-Whitney test was used to analyzed the result data underwent normality test using SPSS (Version 23.0, IBM Corporation) Results: Mann-Whitney test revealed that there was no statistically significant difference in the median amount of mean vertical wear for 6 months in zirconia ($50.84{\mu}m$) and gold ($42.84{\mu}m$) prostheses (P > 0.05). When the opposing teeth were natural, the median amount of mean vertical wear of zirconia and gold prostheses was $47.72{\mu}m$ and $41.97{\mu}m$, respectively, and the median amount of mean vertical wear of enamel was $47.26{\mu}m$ and $44.59{\mu}m$, respectively. Statistical analysis showed no significant difference (P > 0.05). Conclusion: Despite the short study period and the small number of experimental groups, zirconia and gold showed no significant difference in wear during the first 6 months. Opposing natural enamel also showed no significant difference in the wear.

• Journal of Korean Society of Forest Science
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• v.106 no.3
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• pp.288-299
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• 2017

This study was conducted to find out the influence of drought stress on physiological responses of Synurus deltoides. Drought stress was induced by withholding water for 25 days. Leaf water potentials were decreased of both predawn (${\Psi}_{pd}$) and mid-day (${\Psi}_{mid}$) with increasing drought stress, but water saturation dificit (WSD) was 7 times increased. ${\Psi}_{pd}-{\Psi}_{mid}$ showed the significant difference of 0.22~0.18 MPa in stressed before 10 days, and nonsignificant as treatment time became longer. A strong reduction of stomatal conductance ($gH_2O$) and stomatal transpiration rate (E) were observed after 15 days of drought stress Significant reductions of net apparent quantum yield (${\Phi}$) and maximum photosynthesis rate ($Pn_{max}$) were observed after 20 days of drought stress; However, water use efficiency (WUE) was shown the opposite trend. This implies that decrease of photosynthesis rate may be due to an inability to regulate water and $CO_2$ exchanged through the stomata. From JIP analysis, flux ratios (${\Psi}_O$ and ${\Phi}_{EO}$) and performance index on absorption basis ($PI_{ABS}$) were dramatically decreased withholding water after 15 days, which reflects the relative reduction of photosystem II activity. The leaf of S. deltoides showed osmotic adjustment of -0.35 MPa at full turgor and -0.40 MPa at zero turgor, and also cell-wall elastic adjustment of 9.4 MPa, indicating that S. deltoides tolerate drought stress through osmotic adjustment and cell-wall elastic adjustment. The degree of change in water relations parameters such as Vo/DW, Vt/DW decreased with increasing drought stress. This result showed that S. deltoides was exhibited a strong reduction of photosynthetic activity to approximately -0.93 MPa of predawn leaf water potential, and both of osmotic adjustment and cell-wall elastic adjustment in drought stress condition appears to be an important adaptation for restoration in this species.

• Journal of Wetlands Research
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• v.11 no.3
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• pp.49-59
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• 2009

Seasonal changes of the growth characteristics and biomass of Scirpus fluviatilis, a aquatic emergent vascular plant, were investigated to reveal the phenology and the population dynamics and to provide the fundamental resources for the restoration counterplan of the wetland vegetation in the littoral zone of the Upo wetland, Changnyeong-gun, Gyeongsangnam-do, Korea from March 2006 to November 2006. Scirpus fluviatilis was distributed commonly in Upo, Mokpo, Sajipo, Jokjibyeol, and Topyeongcheon upstream and downstream of Upo wetland, and the density was highest in Mokpo. Distribution range for the water depth was 9~49cm, and the highest shoot density in 26~49cm, and the mean shoot density was $119/m^2$, and the mean shoot length was 122.3cm on May 28. The number of the tuber was $104.5/0.25m^2$, and the living tubers were 84.2%. The mean fresh biomass of the living tubers was 3.0g, and those of 1~4g was most as 57.9%. Germination rates of the living tubers was 43.8%, and the maximum rate was in 7~9g and more than 10g. In the pot cultivation, the shoot density of the germinated tubers and the dormant tubers were highest as 13.5 and 9.7, respectively in early August. In the field study, the shoot density had few change before typhoon damage, while the density increased abruptly in November after flooding accompanied with the typhoon 'Ewiniar'. The shoot length in the pot cultivation and in the field study were 100~116cm and 60~170cm, respectively in the growth-end. Biomass allocation rates into the stem, leaf, flower, and underground parts were 8.9%, 6.6%, 0%, and 84.5%, respectively in the pot cultivation of the germinated tubers, and those of the dormant tubers were 7.1%, 7.1%, 0%, and 85.8%, respectively. The tuber number increased to 1.4~4.1 times by the growth-end, so it is concluded that Scirpus fluviatilis is mostly propagated by the vegetative reproduction.

• Journal of the Korean Institute of Traditional Landscape Architecture
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• v.35 no.3
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• pp.76-93
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• 2017

This thesis recapitulates the current status of Nujeongs(樓亭) by the Han River(漢江) from the late Joseon dynasty, and to contemplate the possible options regarding their restoration. The book Yeon-gang-jeong-sa-gi(沿江亭?記) written by Eom Gyeong-su(嚴慶遂) in 1716 was selected as an object of study. After Hanyang was selected to be the capital of Joseon, Han River was considered to be the greatest venue to visit to take some time off and enjoy the view. The nobleman of the Joseon dynasty built Nujeongs around the riverside and enjoyed boating inthe current status of Nujeongs(樓亭) Han River. Eom Gyeong-su, after traveling on a boat to personally collect information, combined such information with preexisting information to create a well-organized and thorough list of the 29 Nujeongs built by the riverbank, which can be found in his book Yeon-gang-jeong-sa-gi. It is probable that a closer look into Yeon-gang-jeong-sa-gi will reveal more information regarding the general atmosphere of the era, which focused on the history and culture of Han River, and will also enable a more thorough research involving the Han River Nujeongs. The Nujeongs listed in Yeon-gang-jeong-sa-gi were analyzed in this paper. Based on the explanations found in Yeon-gang-jeong-sa-gi, the locations of the 29 Nujeongs were checked and reconfirmed, and the origins and the meanings behind their names were analyzed. In addition, the history of the Nujeongs were recapitulated with information gained from the basis of the fact that Yeon-gang-jeong-sa-gi was written in 1716, The origin of each Nujeongs were revisited, and the history of their change and demise were analyzed. Lastly, the sceneries around each Nujeongs were analyzed based on the poetries that were written and read in the respective Nujeongs, and the general taste for the arts in the era was analyzed. Some Nujeongs remain in the form of paintings, enabling us to take a closer look at the institutions and other aspects of the era. The analysis of Yeon-gang-jeong-sa-gi by this paper has revealed the location of some Han River Nujeongs that were unknown previously. Also, the revelation of some history regarding certain Nujeongs that were unknown previously has created an opportunity for the reinterpretation of the spaces surrounding Han River, and also the opportunity for a new story. Han River has lost most of its old self due to repeated exploitation. However, there are some areas where traces of the original form remains and that may be restored, and some areas may be relocated and restored based on existing paintings. Yeon-gang-jeong-sa-gi in particular may provide us with numerous possible options to reinvigorate and restructure the riverside with a more modern interpretation, especially in relation to the Han River cruise ship, as it is a book written after traveling Han River on a boat.

• Journal of Wetlands Research
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• v.18 no.1
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• pp.32-38
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• 2016

The purpose of this study is to investigate the effects of the natural river conservation work and to find remedies for them, targeting Jangsu-cheon with high frequency of use by citizens among the rivers in Incheon Metroplitan City, Korea; for this, this study conducted investigations and analyses of Jangsu-cheon completed in December, 2008. As a result of investigating 3 spots for the water system of Jangsu-cheon over a total of 3 years (2009, 2010, 2014), it was found that benthic macro-invertebrates of a total of 3 phyla, 5 classes, 11 orders, 26 families, 56 species, and 980 specimens were distributed there. When they were analyzed by year, 18 families and 30 species in 2009, right after the natural river conservation work, and 22 families and 37 species in 2010, 2 years after the work, were found, with 7 species increasing in number; after that, as a result of the investigation in 2014, 22 families and 38 species were found, which tells the river has entered the stabilization stage since the recovery in 2010.Therefore, this study could identify: the water environment of the river was improved due to the natural river conservation work for Jangsu-cheon; in addition, Jangsu-cheon showed good ecological environment due to the continuous maintenance of the good wetlands in Incheon Grand Park in the upper area of the river; and the natural river conservation work of Jangsu-cheon created positive effects.