• Proceedings of the Korean Geotechical Society Conference
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• 2010.09c
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• pp.72-77
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• 2010

The Incheon Bridge, which was opened to the traffic in October 2009, is an 18.4 km long sea-crossing bridge connecting the Incheon International Airport with the expressway networks around the Seoul metropolitan area by way of Songdo District of Incheon City. This bridge is an integration of several special featured bridges and the major part of the bridge consists of cable-stayed spans. This marine cable-stayed bridge has a main span of 800 m wide to cross the vessel navigation channel in and out of the Incheon Port. In waterways where ship collision is anticipated, bridges shall be designed to resist ship impact forces, and/or, adequately protected by ship impact protection (SIP) systems. For the Incheon Bridge, large diameter circular dolphins as SIP were made at 44 locations of the both side of the main span around the piers of the cable-stayed bridge span. This world's largest dolphin-type SIP system protects the bridge against the collision with 100,000 DWT tanker navigating the channel with speed of 10 knots. Diameter of the dolphin is up to 25 m. Vessel collision risk was assessed by probability based analysis with AASHTO Method-II. The annual frequency of bridge collapse through the risk analysis for 71,370 cases of the impact scenario was less than $0.5{\times}10^{-4}$ and satisfies design requirements. The dolphin is the circular sheet pile structure filled with crushed rock and closed at the top with a robust concrete cap. The structural design was performed with numerical analyses of which constitutional model was verified by the physical model experiment using the geo-centrifugal testing equipment. 3D non-linear finite element models were used to analyze the structural response and energy-dissipating capability of dolphins which were deeply embedded in the seabed. The dolphin structure secures external stability and internal stability for ordinary loads such as wave and current pressure. Considering failure mechanism, stability assessment was performed for the strength limit state and service limit state of the dolphins. The friction angle of the crushed stone as a filling material was reduced to $38^{\circ}$ considering the possibility of contracting behavior as the impact.

• Journal of Wetlands Research
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• v.20 no.1
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• pp.1-13
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• 2018

Glaux maritima var. obtusifolia is distributed in very limited areas in South Korea and thus designated and protected as an endangered species. This study aimed to identify the diversity of vegetation in the Dangsa coast wetlands, the southern limit of G. maritima var. obtusifolia and to assess determinants of the vegetation and the importance of habitats. The phytosociological method of the $Z{\ddot{u}}rich-Montpellier$ School was used for vegetation classification and mathematical and statistical analyses were also conducted to analyze environmental factors and their relationship with the vegetation. The results of this study showed that there were 4 vegetation units in the Dangsa coast wetlands: Glaux maritima var. obtusifolia-Triglochin maritimum community (included three subcommunities), Puccinellia nipponica s.l. community, Beckmannia syzigachne-Isachne globosa community and Typha laxmannii-Phragmites communis community. It was also found that major determinants of the vegetation include moisture environment, soil depth, water level disturbance, vegetation height, community structure, etc. Glaux maritima was identified to grow most dominantly in the typicum subassociation of Glaux. maritima var. obtusifolia-Triglochin maritimum community, and the species compositions and dominant situations were observed to be similar to those in the southern limit in Japan, adjacent to South Korea. The assessment results indicated that the Dangsa coastal wetlands have a significant meaning from phytogeographical and syngeographical aspects, and contribute as a shelter for diverse species. It is required to establish conservation strategies to accurately determine the value of the wetlands of the Dangsa coast from various perspectives, and to protect and manage them.

• Journal of agriculture & life science
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• v.45 no.6
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• pp.265-278
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• 2011

Effects of the open level of the side window were studied to control the temperature and relative humidity in the fog cooling greenhouse. The greenhouse was cooled by air atomizing spray nozzles of the air and water two-fluid process. The control process includes the measuring of environmental variables, setting and coding of the water balance equations and heat balance in greenhouse, calculating of the roof window open and spray water, and operating of the motor and pump. The target temperature and relative humidity were set at $28^{\circ}C$, 75%, respectively. The three modes of the side window open level were 0%, 50% and 100%. The average dry bulb temperatures of the inside air were 28.2, 27.2 and $26.3^{\circ}C$, respectively and their standard deviation was ranged from $0.4^{\circ}C$to $0.8^{\circ}C$. Also the relative humidity of the 0% mode was the best controlled one with the average of 76.3% and the standard deviation of 2.1%.

• 한국노년학
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• v.38 no.1
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• pp.143-168
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• 2018

While there were posed arguments that social treatment to older persons should be based on the perspective of human rights turning into the 21st century, policy efforts to protect and promote the rights of older persons in international community have slowly proceeded. In this situation existing studies on the rights of older persons in the international perspective have been fragmented in their contents, lacking systematic overview of policy efforts to strengthen the rights of older persons in international community. This study aims to be the one that could be such a systematic study to overview international policy efforts to strengthen the rights of older persons through analyzing the background of posing the problem of the rights of older persons, problems in existing international norms for human rights applicable to older persons, and measures to strengthen the rights of older persons and controversial issues. Existing international norms on human rights that are Universal Declaration of Human Rights, international conventions on the rights in terms of area of rights and target population, and policy recommendations, are narrow in the scope of rights to be protected, and also lack legal force in their implementation. The international community has generally reached a consensus on strengthening the rights of older persons. However, there have been two different positions: strengthening existing norms on human rights versus creating a new convention on the rights of older persons. And also there have appeared many controversial points in both positions. Conclusively this study, arguing the creation of a new convention, suggests implications for Korean society and research studies.

• Journal of Ecology and Environment
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• v.43 no.1
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• pp.43-60
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• 2019

Background: Tropical montane forests played an important role in the provision of ecosystem services. The intense degradation and deforestation for the need of agricultural land expansion result in a significant decline of forest cover. However, the expansion of agricultural land did not completely destruct natural forests. There remain forests inaccessible for agricultural and grazing purpose. Studies on these forests remained scant, motivating to investigate biomass and soil carbon stocks. Data of biomass and soils were collected in 80 quadrats ($400m^2$) systematically in 5 forests. Biomass and disturbance gradients were determined using allometric equation and disturbance index, respectively. The regression modeling is employed to explore the spatial distribution of carbon stock along disturbance and environmental gradients. Correlation analysis is also employed to identify the relation between site factors and carbon stocks. Results: The result revealed that a total of 1655 individuals with a diameter of ${\geq}5cm$, representing 38 species, were measured in 5 forests. The mean aboveground biomass carbon stocks (AGB CS) and soil organic carbon (SOC) stocks at 5 forests were $191.6{\pm}19.7$ and $149.32{\pm}6.8Mg\;C\;ha^{-1}$, respectively. The AGB CS exhibited significant (P < 0.05) positive correlation with SOC and total nitrogen (TN) stocks, reflecting that biomass seems to be a general predictor of SOCs. AGB CS between highly and least-disturbed forests was significantly different (P < 0.05). This disturbance level equates to a decrease in AGB CS of 36.8% in the highly disturbed compared with the least-disturbed forest. In all forests, dominant species sequestrated more than 58% of carbon. The AGB CS in response to elevation and disturbance index and SOC stocks in response to soil pH attained unimodal pattern. The stand structures, such as canopy cover and basal area, had significant positive relation with AGB CS. Conclusions: Study results confirmed that carbon stocks of studied forests were comparable to carbon stocks of protected forests. The biotic, edaphic, topographic, and disturbance factors played a significant variation in carbon stocks of forests. Further study should be conducted to quantify carbon stocks of herbaceous, litter, and soil microbes to account the role of the whole forest ecosystem.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.52 no.5
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• pp.452-460
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• 2019

Exposure to heavy metals through the consumption of contaminated seafood poses a health risk to humans. In Korea, seafood imports are increasing with consumption, with the largest increase in imported seafood coming from Russia. Peter the Great Bay and the Razdolnaya River are both major fisheries and protected areas under the Northwest Pacific Action Plan located near Vladivostok, Russia. This study analyzed heavy metal [cadmium (Cd), lead (Pb), total mercury (tHg), and total (tAs), and inorganic (iAs) arsenic] concentrations in shellfish and crustaceans collected from these areas. Except for iAs, the major toxic heavy metal concentrations of the samples met the national standards (Cd, 0.024-0.982 and 0.003-0.379 mg/kg; Pb, 0.021-1.533 and 0.002 mg/kg; tHg, 0.006-0.015 and 0.036-0.097 mg/kg). The tAs concentrations of three samples exceeded the Russian standard (5 mg/kg, wet weight), whereas the iAs concentrations were extremely low (ND-0.033 mg/kg). Compared with the provisional tolerable weekly intake (PTWI) of the Ministry of Food and Drug Safety and Joint FAO/WHO Expert Committee on Food Additives, the percentages of PTWI of Cd, Pb, and tHg were 0.239%, 0.001-0.049%, and 0.013-0.302%, respectively. These findings reveal that there is no potential health risk by heavy metals through the consumption of Russian seafood obtained in the surveyed areas.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.24 no.5
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• pp.1-14
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• 2021

Excessive development and urbanization have destroyed animal, plant, habitats and reduced biodiversity. In order to preserve species diversity, habitat prediction studies are have been conducted at home and overseas using various modeling techniques. This study was conducted to suggest optimal habitat modeling research by comparing HSI and MaxEnt, which are widely used among habitat modeling techniques. The study was targeted on the endangered species of Prionailurus bengalensis in nearby areas (5460.35km2) including Cheonan City, and the same data were used for analysis to compare those models. According to the HSI analysis, Prionailurus bengalensis's habitat probability was 74.65% for less than 0.5 and 25.34% for more than 0.5 and the top 30% were forest (99.07%). MaxEnt's analysis showed that 56.22% of those below 0.5 and 43.79% of those above 0.5 were found to have a high explanatory power of 78.3% of AUC. The Paired Wilcoxn test, which evaluated the significance of thoes models, confirmed that the mean difference between the two models was statistically significant (p<0.05). Analysis of the differences in the results of those models using the matrix table shows that score 24.43% HSI and MaxEnt was accordance,12.44% of the 0.0 to 0.2 section, 7.22% of the 0.2 to 0.4 section, 2.73% of the 0.4 to 0.6 section, 1.96% of the 0.6 to 0.8, and 0.08% of the 0.9 to 1.0. To verify where the score difference appears, the result values of those models were reset to values from 1 to 5 and overlaid. Overlapping analysis resulted in 30.26% of the Strongly agree values, 56.77% of the agree values, and 11.92% of the Disagree values. The places where the difference in scores occurs were analyzed in the order of forest (45.23%), agricultural land (34.57%), and urbanization area (7.65%). This confirmed that the analysis of the same target species within the same target site also has differences in forecasts depending on the modelling method. Therefore, a novel analysis method combining the advantages of each modeling in habitat prediction studies should be developed, and future study may be used to select Prionailurus bengalensis and species-protected areas and species protection areas in the future. Further research is judged to require higher accuracy studies through the use of various modeling techniques and on-site verification.

• Journal of Korea Water Resources Association
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• v.54 no.3
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• pp.191-201
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• 2021

Rivers have been damaged due to rapid urbanization, and river management has been carried out focusing on flow and flood control functions. Recently, interest in river restoration, emphasizing the environmental aspects of rivers, is increasing, but the beginning of river restoration requires an appropriate evaluation of the environmental flow required for the ecosystem. This study analyzed the effects on the habitat of the river ecosystem by estimating the changes in flow regime and environmental flow following the construction of the Buhang dam in Gamcheon, the first tributary of the Nakdong River. To evaluate the environmental flow, the dominant species of Gamcheon, Zacco Platypus, and the protected species Squalidus gracilis majime, and riparian vegetation were selected, and the environmental flow was calculated using the HEC-EFM (Ecosystem Function Model). The evaluated environmental flow was linked with hydraulic analysis and GIS platform, and habitat area change and habitat connectivity analysis before and after dam construction were performed by spatial habitat analysis in the river. Based on the results of this study, it can be used as a river restoration project and a dam operation plan considering the river environment through the calculation of environmental flow and habitat connectivity analysis to improve the habitat of the river ecosystem.

• Applied Chemistry for Engineering
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• v.32 no.4
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• pp.361-370
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• 2021

Carbon fiber reinforced polymer (CFRP) is one of the composite materials, which has a unique property that is lightweight but strong. The CFRPs are widely used in various industries where their unique characteristics are required. In particular, electric and unmanned aerial vehicles critically need lightweight parts and bodies with sufficient mechanical strengths. Vehicles using the battery as a power source should simultaneously meet two requirements that the battery has to be safely protected. The vehicle should be light of increasing the mileage. The CFRP has considered as the one that satisfies the requirements and is widely used as battery housing and other vehicle parts. On the other hand, in the battery area, carbon fibers are intensively tested as battery components such as electrodes and/or current collectors. Furthermore, using carbon fibers as both structure reinforcements and battery components to build a structural battery is intensively investigated in Sweden and the USA. This mini-review encompasses recent research trends that cover the classification of structural batteries in terms of functionality of carbon fibers and issues and efforts in the battery and discusses the prospect of structural batteries.

• Journal of Legislation Research
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• no.41
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• pp.7-42
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• 2011

The social welfare law concerning the children, the elderly and the disabled has been sufficiently in the center of the discussion in the academic as well as practical arena. One can find however rarely academic proposals about the way of understanding, spheres affiliated with this legal system, and systematic characteristics. So these problems stay now vague. This article aims to approach to these points of issue. First, it tries to reveal the physical, psychological and psychic characteristics of these group of people. These situation are not to be effectively protected by norms and measures provided by other instruments of social security, i.e. social insurances and social assistances. Second, based upon these functional limits inherent to these instruments of social security the own system of the social welfare law is explored in this article. The discussing points are as follows; 1. the concept of social welfare law, 2. as core principles; realization of the personality and freedom based upon self-determination right, universalism and equality. 3. rearrangements of the legal provisions to bring harmony with the legal purpose and function of social welfare law. Finally, it is pointed that the evaluation of the relevant legislation is essential, since in this area the difference between the norm purpose and the reality could be immense.