• Journal of Chest Surgery
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• v.29 no.4
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• pp.373-380
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• 1996

Prevention of thromboembolism is the most important task in the development of bioconpatible small caliber artificial vascular graft. In normal vessels, vascular endothelial cells maintain homeosatsis by secreting numerous factors. The aim of this study is to develope a method which Improves biocompatibility of small caliver polyurethane graft using endothelial cell culture technique, and ev luate the efTectiveness of extracelluar matrix for endothelization which was produced by cultured fibroblast. Methods ; Multiporous polyurethane tube of 3 mm diameter, 0.3 mm thickness was manufactured for vascular graft. Three mongrel dogs were intubated and internal jugular veins removed. Extracelluar matrix produced by cultured flbrobast which was obtained from dog's internal jugular vein were coated to the polyurethane graft. Then, endothelial cells extracted from Jugular vein were cultured and fixed on the extracelluar matrix layer of vascular graft. Endothelial cell coated vascular grafts were implanted to the carotid arteries of experimental dogs as interposed autograft. Implanted grafts were removed after 3 and 6 weeks. As a control, PTFE graft was interposed on carotid artery. These experiments demonstrated that extracelluar matrix produced by fibroblast can afford a base for endothelial cell linings of polyurethane graft. Although thrombosis were developed on autografted en othelial cell coated graft, 33% opening was noticed, and showed less adhesion to adjacent tissue layer. These findings suggest that fiboblast produced extracelluar matrix which can be used for edothelial cell lining vascular graft, and by improving the cultured endothelial cell function, there will be a new modality for reducing thrombosis on small vascular graft.

• Journal of the Korean Geographical Society
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• v.50 no.3
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• pp.255-276
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• 2015

This paper presents a multi-agent system model of land-use and cover changes, which is developed and applied to the Gariwang-san and its vicinity, located in Pyeongchang and Jeongseon-gun, Gangwon province, Korea. The Land Use Dynamics Simulator (LUDAS) framework of this study is well suited for representing the spatial heterogeneity and dynamic interactions between human and natural environment, and capturing the impacts of forest-opening policy interventions to future socio-economic and natural environment changes. The model consists of four components: (1) a system of human population, (2) a system of landscape environment, (3) decision-making procedures integrating human(or household), environmental and policy information into forest land-use decisions, and (4) a set of policy scenarios that are related to the forest-opening. The results of model simulation by different combination of various forest management scenarios are assessed by the levels of household income, ecosystem service value and income inequality in the study region. As a result, the optimal scenario of forest-opening policies in the study region is to open the forest to local residential community for the purpose of recreation, considering the distinctive topographical feature. The model developed in this research is expected to contribute to a decision support system for sustainable forest management and various land-use policies in Korea.

• Journal of Environmental Policy
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• v.13 no.1
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• pp.69-93
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• 2014

The aim of this research was to develop a climate change vulnerability index at the district level (Si, Gun, Gu) with respect to the health care sector in Korea. The climate change vulnerability index was esimated based on the four major causes of climate-related illnesses : vector, flood, heat waves, and air pollution/allergies. The vulnerability assessment framework consists of six layers, all of which are based on the IPCC vulnerability concepts (exposure, sensitivity, and adaptive capacity) and the pathway of direct and indirect impacts of climate change modulators on health. We collected proxy variables based on the conceptual framework of climate change vulnerability. Data were standardized using the min-max normalization method. We applied the analytic hierarchy process (AHP) weight and aggregated the variables using the non-compensatory multi-criteria approach. To verify the index, sensitivity analysis was conducted by using another aggregation method (geometric transformation method, which was applied to the index of multiple deprivation in the UK) and weight, calculated by the Budget Allocation method. The results showed that it would be possible to identify the vulnerable areas by applying the developed climate change vulnerability assessment index. The climate change vulnerability index could then be used as a valuable tool in setting climate change adaptation policies in the health care sector.

• Journal of Environmental Policy
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• v.6 no.1
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• pp.41-60
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• 2007

Attempts were made to define the elements of debates, impact of decisions of the Access to Genetic Resources and Benefit-sharing(ABS) of the Conference of the Parties(COP) to the Convention on Biological Diversity(CBD) In Korea. Providing policy suggestions to cope with ABS, a cross-cutting issue of the meetings of the COP, was also undertaken. Meetings concerning ABS deal with several key matters such as an international regime, which is a legally binding implementation tool of the Bonn Guidelines, an international certificate of genetic resources' origin/source/legal provenance, and disclosure of origin of genetic resources, compliance measures with prior informed consent of the Contracting Parties providing such resources and with mutually agreed terms on which access was granted. Developing countries, rich in biodiversity and genetic resources, use the CBD as a major tool to maximize their national profits. They demand for national sovereign rights for the genetic resources and indigenous communities providing associated traditional knowledge. At the meetings of the COP, in addition, they requested that developed countries should transfer technologies and provide a financial mechanism for resource conservation to them. On the contrary, the developed countries argue that facilitating access to genetic resources is essential for scientific research and development, and that both Intellectual Property Rights and biotechnology using genetic resources should be protected to maximize their national benefits. Decisions of the COP concerning the Bonn Guidelines and compliance measures with ABS will affect on various socioeconomic fields of Korea, a country which is short of genetic resources. Especially, the importation of genetic resources and land development which might damage genetic resources will be limited seriously. Consequently, overall expenses will increase for the securing genetic resources from the foreign countries and developing biotechnology for conservation and sustainable uses of genetic resources. To minimize the adverse impacts, we endeavor to establish our clear standpoint and to lead the international trends, which are favorable for us. In order to achieve these objectives, government needs i) to proceed researches to lead the international ABS debates actively and to prepare the expected decisions of the future meetings of the COP, ii) to establish a national implementation plan to cope with the ABS and its related decisions, iii) to examine and improve the efficiencies of the national implementation plan with a proper monitoring system, and iv) cope with the other international meetings including the meetings of Trade Related Intellectual Properly Rights and International Treaty on Plant Genetic Resources for Food and Agriculture actively.

• Journal of Environmental Policy
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• v.10 no.1
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• pp.49-70
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• 2011

The numerous efforts have been made in understanding generation and transportation mechanism of nonpoint source pollutants from agricultural areas. Also, the water quality degradation has been exacerbated over the years in many parts of Korea as well as other countries. Nonpoint source pollutants are transported into waterbodies with direct runoff and baseflow. It has been generally thought that groundwater quality is not that severe compared with surface water quality. However its impacts on groundwater in the vicinity of stream quality is not negligible in agricultural areas. The SWAT model has been widely used in hydrology and water quality studies worldwide because of its flexibilities and accuracies. The spatial property of each HRU, which is the basic computational element, is not presented. Thus, the SWAT HRU mapping module was developed in this study and was applied to the study watershed to evaluate recharge rate and $NO_3-N$ loads in groundwater. The $NO_3-N$ loads in groundwater on agricultural fields were higher than on forests because of commercial fertilizers and manure applied in agricultural fields. The $NO_3-N$ loads were different among various crops because of differences in crop nutrient uptake, amount of fertilizer applied, soil properties in the field. As shown in this study, the SWAT HRU mapping module can be efficiently used to evaluate the pollutant contribution via baseflow in agricultural watershed.

• Environmental and Resource Economics Review
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• v.24 no.3
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• pp.573-605
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• 2015

This study proposed scenarios of tax reform regarding taxation on bituminous coal for power generation since July 2015 and July 2014, estimated its impact on SMP, settlement price, tax revenue from year 2015 to year 2029. These scenarios are compared with those of the standard scenario. To estimate them, the power system simulation was performed based on the government plan, such as demand supply program and the customized model to fit Korea's power system and operation. Imposing a tax on bituminous coal for power generation while maintaining tax neutrality reducing tax rate on LNG, the short-term SMP is lowered than the one of the standard scenario. Because the cost of nuclear power generation is still smaller than costs of other power generation, and the nuclear power generation rarely determines SMPs, the taxation impact on SMP is almost nonexistent. Thus it is difficult to slow down the electrification of energy consumption due to taxation of power plant bituminous coal in the short term, if SMP and settlement price is closely related. However, in the mid or long term, if the capacity of coal power plant is to be big enough, the taxation of power plant bituminous coal will increase SMP. Therefore, if the tax reform is made to impose on power plant bituminous coal in the short term, and if the tax rate on LNG is to be revised after implementing big enough new power plants using bituminous coal, the energy demand would be reduced by increasing electric charges through energy tax reform. Both imposing a tax on power plant bituminous coal and reducing tax rate on LNG increase settlement price, higher than the one of the standard scenario. In the mid or long term, the utilization of LNG complex power plants would be lower due to an expansion of generating plants, and thus, the tax rate on LNG would not affect on settlement price. Unlike to the impact on SMP, the taxation on nuclear power plants has increased settlement price due to the impact of settlement adjustment factor. The net impact of energy taxation will depend upon the level of offset between settlement price decrease by the expansion of energy supply and settlement price increase by imposing a tax on energy. Among taxable items, the tax on nuclear power plants will increase the most of additional tax revenue. Considering tax revenues in accordance with energy tax scenarios, the higher the tax rate on bituminous coal and nuclear power, the bigger the tax revenues.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.1-15
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• 2017

Daecheong Reservoir was made by the construction of a large dam (>15 m in height) on the middle to downstream of the Geum River and the discharge systems have the watergate-spillway (WS), a hydropower penstock (HPP), and two intake towers. The purpose of this study was to investigate the limnological anomalies of turbid water reduction, green algae phenomenon, and oligotrophic state in the lower part of reservoir dam site, and compared with hydro-meteorological factors. Field surveys were conducted in two stations of near dam and the outlet of HPP with one week intervals from January to December 2000. Rainfall was closely related to the fluctuations of inflow, outflow and water level. The rainfall pattern was depended on the storm of monsoon and typhoon, and the increase of discharge and turbidity responded more strongly to the intensity than the frequency. Water temperature and DO fluctuations within the reservoir water layer were influenced by meteorological and hydrological events, and these were mainly caused by water level fluctuation based on temperature stratification, density current and discharge types. The discharges of WS and HPP induced to the flow of water bodies and the outflows of turbid water and nutrients such as nitrogen and phosphorus, respectively. Especially, when hypoxic or low-oxygen condition was present in the bottom water, the discharge through HPP has contributed significantly to the outflow of phosphorus released from the sediment into the downstream of dam. In addition, HPP effluent which be continuously operated throughout the year, was the main factor that could change to a low trophic level in the downreservoir (lacustrine zone). And water-bloom (green-tide) occurring in the lower part of reservoir was the result that the water body of upreservoir being transported and diffused toward the downreseroir, when discharging through the WS. Finally, the hydropower effluent was included the importance and dynamics that could have a temporal and spatial impacts on the physical, chemical and biological factors of the reservoir ecosystem.

• Korean Journal of Environment and Ecology
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• v.23 no.5
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• pp.431-438
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• 2009

The main purpose of this research is to prepare and provide basic materials for the propagational strategy of eelgrass by investigating on the morphological adaptation of Korean Zostera marina to ocean currents. An eelgrass plant mainly consists of rhizome, leaf sheath, leaves and roots. The rhizome is the horizontal stem of the plant that serves as the backbone from which the leaves and roots emerge. The leaf sheath is the bundle at the base of the leaves that holds the leaves together, protecting the meristem, the primary growth point of the shoot. Leaves originate from a meristem which is protected by a sheath at the actively growing end of the rhizome. As the shoot grows, the rhizome elongates, moving across or within the sediment, forming roots as it progresses. The aggregated leaves from the leaf sheath are found to have two cell layers on one side and multiple layers of airy tissues called aerenchyma on the other. The aerenchyma tissues are developed in multi-layered cell structures surrounding the veins which are formed in the leaf sheath. Generative shoots are made of rhizomes, which are circular or ovoidal, stem, and spathe and spadix. The transverse section of rhizome and the stem and central floral axis is found to be circular, ovoid and in the shape of convex respectively, and the vascular bundle, which is a part of transport system, has one large tube in the center and two small tubes on both sides. The layers of collenchyma cells numbered from 12 to 15 in the stem, and from 7 to 12 in the rhizome. The seed coat is composed of sclereids, small bundles of sclerenchyma tissues, which prevent the influx of sea water from the outside and help endure the environmental stress. In conclusion, alternative multi-layer structure in circular, convex type aggregated leaf base are interpreted to morphological adaption as doing tolerable elastic structure through movement of seawater. The generative shoots develop long slim stem and branches in circular or ovoidal shapes to minimize the adverse impacts of sea current, which can be interpreted as the plant's morphological adaptation to its environment.

• Korean Journal of Agricultural and Forest Meteorology
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• v.13 no.3
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• pp.115-122
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• 2011

The impacts of elevated temperature and $CO_2$ were studied on the seedlings of Maackia amurensis and Viburnum opulus var. calvescens. The seedlings were grown in controlled-environment growth chambers with four combinations of temperature and $CO_2$ treatments: $25^{\circ}C$ + ambient $CO_2$ (400 ppm), $25^{\circ}C$ + elevated $CO_2$ (800 ppm), $30^{\circ}C$ + ambient $CO_2$ (400 ppm), and $30^{\circ}C$ + elevated $CO_2$ (800 ppm). Under elevated temperature and $CO_2$ concentration, the dry weight decreased in seedlings of M. amurensis, but increased in seedlings of V. opulus var. calvescens. In addition, the shoot to root (S/R) ratio in M. amurensis reduced but that of V. opulus var. calvescens increased under elevated $CO_2$ concentration. The S/R ratios of two tree species increased under higher temperature. M. amurensis represented lower carboxylation efficiency under higher temperature and $CO_2$ concentration and that of V. opulus var. calvescens showed lower values under the only higher temperature. Photosynthetic pigment content of in the leaves of M. amurensis was lower under higher $CO_2$ concentration and higher under the increase of temperature, but that of V. V. opulus var. calvescens decreased according to the increase of temperature. Chlorophyll a/b ratios of M. amurensis and V. V. opulus var. calvescens decreased obviously with the increase of $CO_2$ concentration and temperature, respectively. In conclusion, the growth and physiological responses under the environmental changes such as temperature and $CO_2$ concentration depend on the tree species. Therefore, more studies are needed to predict the response of each tree species against the climate changes.

• Journal of Korea Port Economic Association
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• v.34 no.4
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• pp.141-160
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• 2018

In this paper, to analyze the perception and response strategy of Korean ship owners on Global Sulphur Cap 2020, examined the IMO environmental regulation status focusing on MARPOL Annex VI regulation about air pollution prevention, technological measures to reduce SOx emission, shipping industry and management status of Korean ship owners. First of all, the questionnaire was conducted for Korean ship owners after selecting the evaluation factors. The purpose of this study was to investigate the difference of the perception and response strategy of Korean ship owners by corporation size and main vessel type using frequency and cross analysis. It is confirmed that various researches on SOx emission reduction have been carried out from various points of view at home and abroad. In this study, existing studies related to technical factors for regulatory response and economics analysis were examined and evaluation factors were selected. As a result of analysis, it is found that large-sized shipping companies are more prepared for regulatory response than small and medium-sized bulk carrier owners. There were similar perception and the direction of response strategy about the impacts by corporation size and main vessel type. In about two years to be implemented in 2020, It is necessary to find an appropriate response strategy based on the support policy of the government and related organizations and the systematic analysis of the ship owners. Through this study, although the difference between the perception and response strategy of the ship owners by corporation size and main vessel type was understood, it was found that there were limitations on specific response strategy and corporate data collection. In future research, we should overcome the limitations of this study and conduct an in-depth study.