• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.766-771
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• 2016

This study examined the long-term durability of PC boxes, which was manufactured by low-carbon eco-friendly concrete using an alternative binder to cement and alternative fine aggregate to sand and microwave heat curing system to reduce the construction cost of a near-surface transit system. Based on the test results, the initial compressive strength of microwave heat cured concrete was higher than that of the steam cured concrete, but those were similar in the long-term age. In addition, there was no significant difference between the two curing conditions in the chemical resistance and the freeze-thawing resistance, and the chloride ion penetration level of the concrete cured by two methods was very low. Therefore, low-carbon eco-friendly concrete and microwave heat curing technology are expected to contribute to the economic construction of a near-surface transit system, and reduce carbon dioxide emissions and environmental impact.

• Safety and Health at Work
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• v.7 no.4
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• pp.381-388
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• 2016

Background: Relationships among portable scanning mobility particle sizer (P-SMPS), condensation particle counter (CPC), and surface area monitor (SAM), which are different metric measurement devices, were investigated, and two widely used research grade (RG)-SMPSs were compared to harmonize the measurement protocols. Methods: Pearson correlation analysis was performed to compare the relation between P-SMPS, CPC, and SAM and two common RG-SMPS. Results: For laboratory and engineered nanoparticle (ENP) workplaces, correlation among devices showed good relationships. Correlation among devices was fair in unintended nanoparticle (UNP)-emitting workplaces. This is partly explained by the fact that shape of particles was not spherical, although calibration of sampling instruments was performed using spherical particles and the concentration was very high at the UNP workplaces to allow them to aggregate more easily. Chain-like particles were found by scanning electron microscope in UNP workplaces. The CPC or SAM could be used as an alternative instrument instead of SMPS at the ENP-handling workplaces. At the UNP workplaces, where concentration is high, real-time instruments should be used with caution. There are significant differences between the two SMPSs tested. TSI SMPS showed about 20% higher concentration than the Grimm SMPS in all workplaces. Conclusions: For nanoparticle measurement, CPC and SAM might be useful to find source of emission at laboratory and ENP workplaces instead of P-SMPS in the first stage. An SMPS is required to measure with high accuracy. Caution is necessary when comparing data from different nanoparticle measurement devices and RG-SMPSs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.563-570
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• 2018

Existing online voting is not being used for public elections due to uncertainty about security threats, and offline voting costs a lot of money. As an alternative, blockchain is emerging. Applying blockchain technology to online voting will ensure transparency and confidentiality, because voter information and aggregate information are distributed and managed. Since a blockchain distributes the voting information, it will be more secure than existing central server - based online voting systems. If blockchain technology is applied to public elections, and the transparency and confidentiality of the voting information is guaranteed, the cost of voting will be greatly reduced. This paper tries to apply to an online voting system the Ethereum platform from among the blockchain technologies. Ethereum is a highly scalable blockchain technology that provides a smart contract based on the Solidity language to develop an online voting contract and to distribute the contract to each voter. Each voter votes on the contract that has been distributed, and the votes are distributed to other voters. The experiment verifies the consistency of the stored voting information.

• Journal of The Korean Digital Architecture Interior Association
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• v.11 no.3
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• pp.79-88
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• 2011

In the context of sustainability which is understood as equilibrium among three elements; human, space and time, the imbalance within the Seoul metropolitan area hinders its own area or the nation from development. Claims for the balanced development in the area are set up on the premise that there is a locational order of priority among the zones named 'overpopulation suppression', 'growth management' and 'conservation'. Based on the systematic consideration of competitiveness this study adopts the premise as a research hypothesis. Factor scales derived from the factor analysis, a kind of multivariate dependence analysis play an important role in this research process since they are measured by interval-ratio level and can be used for dependent variables in the statistical analysis. The hypothesis test carried out by means of the analysis of variance(ANOVA) concludes that the hypothesis assuming no difference in the competitiveness is rejected but the alternative hypothesis of the locational order mentioned above should be adjusted. Eigenvalues derived from the factor analysis could be used as weights for aggregate factor scales and the scales show that the priority is in the order of growth management - overpopulation suppression - conservation zones. This finding has also a significant implication that the countermeasures to cope with the lowering of the competitiveness resulted from the continuous and absolute restraints should be provided. And strategic approaches which are composed of key factors for each zone are deducted from in-depth review. (1) overpopulation suppression zone; health-welfare, educational base, public service factors, focusing on health-welfare one, (2) growth management zone; public service factor and (3) conservation zone; health-welfare, educational base factors, also focusing on health-welfare one.

• Journal of the Society of Disaster Information
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• v.9 no.4
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• pp.493-502
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• 2013

The purpose of this research is to estimate the drying shrinkage and durability of concrete using the fine river sand to utilize it actively as an alternative aggregate for concrete. For this purpose, the fine river sand samples were collected at the mid and down stream of main stream of Nakdong-River, and then the concrete specimens using the fine river sand were made according to strength level. After obtaining relation equation between compressive strength and cement-water ratio from the mix experiment result, the concrete specimens using different fine river sand were made for the specified concrete strength of 35MPa, and then their drying shrinkage and durability such as the resistance to freeze and thaw and carbonation were evaluated. It was observed from the test result that the durability of concrete using fine river sand was similar to that of concrete using reference sand, but the drying shrinkage of concrete using the fine river sand with small fineness was comparatively larger than that of concrete using reference sand.

• Korean Journal of Soil Science and Fertilizer
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• v.46 no.3
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• pp.216-222
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• 2013

Fertilizer management has the potential to promote the storage of carbon and nitrogen in agricultural soils and thus may contribute to crop sustainability and mitigation of global warming. In this study, the effects of fertilizer practices [no fertilizer (Control), chemical fertilizer (NPK), Compost, and chemical fertilizer plus compost] on soil total carbon (TC) and total nitrogen (TN) contents in inner soil profiles of paddy soil at 0-60 cm depth were examined by using long-term field experimental site at $42^{nd}$ years after installation. TC and TN concentrations of the treatments which included N input (NPK, Compost, NPK+Compost) in plow layer (0-15 cm) ranged from 19.0 to 26.4 g $kg^{-1}$ and 2.15 to 2.53 g $kg^{-1}$, respectively. Compared with control treatment, SOC (soil organic C) and TN concentrations were increased by 24.1 and 31.0%, 57.6 and 49.7%, and 72.2 and 54.5% for NPK, Compost, and NPK+Compost, respectively. However, long term fertilization significantly influenced TC concentration and pools to 30 cm depth. TC and TN pools for NPK, Compost, NPK+Compost in 0-30 cm depth ranged from 44.8 to 56.8 Mg $ha^{-1}$ and 5.78 to 6.49 Mg $ha^{-1}$, respectively. TC and TN pools were greater by 10.5 and 21.4%, 30.3 and 29.6%, and 39.9 and 36.3% in N input treatments (NPK, Compost, NPK+Compost) than in control treatment. These resulted from the formation and stability of aggregate in paddy soil with continuous mono rice cultivation. Therefore, fertilization practice could contribute to the storage of C and N in paddy soil, especially, organic amendments with chemical fertilizers may be alternative practices to sequester carbon and nitrogen in agricultural soil.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.3
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• pp.1481-1488
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• 2013

The purpose of this experimental research is to suggest a base data to utilize the fine sand of Nakdong-River actively as an alternative aggregate for concrete. For this purpose, after the typical fine sand samples were collected at the mid stream and down stream of main stream of Nakdong-River, the physical properties of them and the mix characteristics of concrete using those were estimated. As a result, it was observed from the test result that mix characteristics between concrete using fine sand and concrete using well-graded reference sand made little differences since unit water content and unit cement content of concrete using fine sand increased only a little than those of concrete using reference sand for specified compressive strength.

• Proceedings of the KAIS Fall Conference
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• 2004.06a
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• pp.253-257
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• 2004

Platelet aggregation is a complex phenomenon that probably involves several intracellular biochemical pathways. When activated, platelets change shape, aggregate and release the contents of their intracellular granules. The interactions between platelets and blood vessel walls are important in the development of thrombosis and cardiovascular diseases. When blood vessels are damaged, platelet aggregation occurs rapidly to form haemostatic Plugs or arterial thrombi at the sites of vessel injury or in regions where blood flow is disturbed. These thrombi are the source of thromboembolic complications of atherosclerosis, heart attacks, stroke, and peripheral vascular disease. Therefore, the inhibition of platelet function represents a promising approach for the prevention of thrombosis. Plants constitute a rich source of bioactive chemicals such as phenolics, terpenoids and alkaloids. Plant extracts may be an alternative to currently used medicinal source because they constitute a rich source of bioactive chemicals. This study was performed to investigate the antiplatelet activity of extract of Tabebuia impetiginosa Martius ex DC (Taheebo) and find out which fractions to this activity in rabbit platelet. Taheebo was methanol extracted and solvent fractionated in to five fractions (hexane, chloroform, ethylacetate, butanol and water). And each fractions were investigated inhibitory effects on platelet aggregation induced by various agonists using washed rabbit platelets in vitro.

• 한국사회정책
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• v.25 no.2
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• pp.243-280
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• 2018

This paper examines the discussion on the income-led growth known as the core economic strategy of Moon's administration in terms of Korean welfare regime. Although the income-led growth strategies have presented various issues, the income-led growth strategy seems to be a timely alternative discourse that emphasizes the demand side, considering supply-oriented growth strategies have caused long-term recession and deepening of inequality. It is important that the income-led growth strategy places social expenditures as an important growth engine for virtuous cycle of production and consumption. However, this paper has confirmed that simply raising wages and increasing social expenditure do not increase the aggregate demand and production. Moreover, empirical studies have shown that the inclusion of external sectors and liabilities into the analysis weakens the wage-led growth of the Korean economy. For this reason, this study concluded that the government's sophisticated policy intervention is necessary for the increase of real wages and social spending to be economic growth.

• Journal of Soil and Groundwater Environment
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• v.27 no.3
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• pp.22-40
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• 2022

The goal of this study was to estimate the possible scattering distance of deicer from the highway and the impact range of deicer on soil quality in terms of plant growth. Among the major elements (Ca²⁺, Cl^- and Na⁺) of deicer, Ca²⁺and Cl^- are usually applied as fertilizer to soil. Therefore both elements (Ca²⁺and Cl^-) were not appropriate for a tracer of deicer at the agricultural area. In this study, SAR (sodium adsorption ratio) of soil was proposed as an alternative tracer to confirm the distribution of the deicer around the highway areas. Because deicer is the main anthropogenic source of Na⁺ around the highway areas and does harm to the physical properties of soil and plant growth through the destruction of soil aggregate, SAR would be an recommendable tracer to access the distribution of deicer as well as adverse effect on soil quality at highway areas. The influence range of deicer based on SAR of soil was estimated to be less than 20 m distance from the highway even though the possible flying distance of deicer was found to be more than 100 m from the highway. However the deicer seriously deposited within 10 m from the highway.