• Journal of Korean Society of Water and Wastewater
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• v.19 no.6
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• pp.781-790
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• 2005

Granular Activated Carbon(GAC) is widely used in drinking water treatment. Many of the problems occurring in the GAC process are associated with the operation goal and performance. The purpose of this study were to evaluate the design, operation, and performance of granular activated carbon process in D water treatment plant. The optimal operation conditions of GAC process such as backwashing condition, granular activated carbon replacement time were discussed. The design, operation and performance of GAC process is influenced by their raw water characteristics and placement within the treatment process sequence. A critical analysis of plants experience and the information from the literature identifies the effectiveness of GAC process and indicates where modifications in design and operation could lead to improved performance. It would be useful to evaluate and optimize the GAC process in other treatment plant.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.5
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• pp.760-768
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• 2016

Recently, as one of the policies for carbon free operation method of independent power system replacing diesel generator with renewable energy such as wind power and photovoltaic(PV) system has been presented. Therefore, this paper proposes an operation algorithm and modeling of independent power system by considering CVCF(constant voltage constant frequency) ESS(energy storage system) for constant frequency and voltage, LC(load control) ESS for demand and supply balancing and SVC(static var compensator) for reactive power compensation. From the simulation results based on the various operation scenario, it is confirmed that proposed operation algorithm and modeling may contribute stable operation and carbon free in independent power system.

• Journal of Korean Society of Transportation
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• v.33 no.3
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• pp.237-246
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• 2015

Operation and Maintenance in road infrastructure is repetitive carbon emissions activities to preserve the road in its originally constructed condition. In the view of road planning and construction, operation, and maintenance of life cycle, operation and maintenance stage quantification of carbon emissions is very important because it is easily accessible activities to reduce carbon emissions in road infrastructure that existing and new road. However, carbon emissions estimation in operation and maintenance stage is yet to do, because data collection is so hard and carbon emissions estimation methodology is very complicated. In this study, a basic unit of carbon emission in the operation and maintenance stage of the road infrastructure was developed in order to get the quantitative determination of carbon that occurring. Carbon emissions of the Expressway and Common state road was calculated by using the basic unit of carbon emission and application plan of basic unit of carbon emission are presented.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.196-197
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• 2014

Low carbon construction is an important operation management goal such as cost, time, and quality in construction community. This paper introduces a system which measures the variability of carbon dioxide amounts. First, this system allows creating construction operation models of which the level of detail is breakdown into the work task level. Second, the system implements sensitivity analysis along with a ranges of resources that are allocated in an operation model. It facilitates to find the optimal resource combination using the operation performances such as the amount of emissions, operation completion time, and cost. Lastly, it identifies the best fit probability distribution functions of performance criteria given a certain resource combination. It allows project manager to query the percentages to complete the operation within a limitation specified by the system users.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.1D
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• pp.1-11
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• 2012

The presidential council on national competitiveness and the national police agency have initiated a national project to refresh the road traffic control and operation systems to increase operational efficiency at signalized intersections. It would reduce the number of stops and delay of vehicles at intersections and thus mitigate congestion and emission. Although significant reduction of carbon is expected as a consequential result, such effects has yet been studied since traffic operation was behind of interest in the field of green transportation where planning was mainly involved. This paper delivers the macroscopic effects of carbon reduction of the selected items of the national project: the ones managed by the police agency. The results showed that the studied items yield significant reduction of carbon: pedestrian push button operation, flashing signal operation, progression, lagging left turns, permitted left turn, and actuated left-turn operation would reduce 12.31%, 3.27%, 2.44%, 0.97%, 0.81%, and 0.72% of the total amount of carbon emitted a year in a whole transportation sector, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.653-661
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• 2017

This study compares and analyzes the operation costs of traditional and direct delivery strategies considering carbon emissions. For the determination of minimum operation costs and order quantity, we use the Economic Order Quantity (EOQ) model, which is the proper method for calculate the operation costs by logistics strategy. Using the classical EOQ model, we expand the EOQ model considering carbon emissions and domestic logistics environment. We conduct an empirical study on two agri-food logistics strategies under limitation of the carbon emissions using the expanded EOQ model. From the results of the empirical study, we find that the operation costs of direct delivery strategy are about 50% lower than those of the traditional strategy. Economic order quantity is also smaller than that of the traditional strategy. These results indicate that agri-food products can be transported quickly and freshly under direct delivery strategy. Consequently, considering carbon emissions, direct delivery logistics strategy are analyzed to have more positive effect on economic and environmental issues than existing logistics strategy. It is judged that direct strategy will also increase the freshness of agricultural products.

• Journal of Electrical Engineering and Technology
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• v.5 no.4
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• pp.530-537
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• 2010

By development of renewable energy and more efficient facilities in an increasingly deregulated electricity market, the operation cost of distributed generation (DG) is becoming more competitive. International environmental regulations of the leaking carbon become effective to reinforce global efforts for a low-carbon paradigm. Through increased DG, operators of DG are able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, a community energy system (CES) with DGs is a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to transmission service charges and other costs. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize profit. Considering the international environment regulations, CE will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper introduces the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES. A Particle Swarm Optimization (PSO) will be used to solve this complicated problem. The optimal operation of DG represented in this paper would guide CES and system operators in determining the decision making criteria.

• Journal of Korean Society of Water and Wastewater
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• v.27 no.3
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• pp.363-371
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• 2013

In this study, effect of activated carbon size on flux and fouling of membrane was investigated on activated carbon and membrane hybrid system. The activated carbon was prepared with crushing and screening. The activated carbon was named by A100, B100, A200, B200, A325 and B325 due to size of activated carbon. The permeability for A100, B100, A200 and B200 showed no significant difference. However, the permeability for A325 and B325 was decreased rapidly and was lowed due to increase the concentration of NOM. Main resistance for A100, B100, A200 and B200 was identified as irreversible fouling. However main resistance for A325 and B325 was identified as reversible fouling. The smaller activated carbon adsorbs NOM faster than bigger particles, which can show high permeability at early stage of the operation and then showed faster decrease of permeability at end of the operation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.8
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• pp.1504-1511
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• 2009

By development of renewable energies and high-efficient facilities and deregulated electricity market, the operation cost of distributed generation(DG) becomes more competitive. The amount of distributed resource is considerably increasing in the distribution network consequently. Also, international environmental regulations of the leaking carbon become effective to keep pace with the global efforts for low-carbon paradigm. It contributes to spread out the business of DG. Therefore, the operator of DG is able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, community energy system(CES) having DGs is recently a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to the transmission service charges and etc. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize the profit. If there is no regulation for carbon emission(CE), the generators which get higher production than generation cost will hold a prominent position in a competitive price. However, considering the international environment regulation, CE newly will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper will introduce the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES and Particle Swarm Optimization (PSO) will be used to solve this problem. The optimal operation of DG represented in this paper is to be resource to CES and system operator for determining the decision making criteria.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.1
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• pp.88-93
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• 2001

Carbon fiber epoxy composite are widely used in airframe structures, space vehicles, sports equipment, and high speed reciprocating parts for industrial machinery. In this paper, the groove processing characteristics of carbon fiber epoxy com-posite was experimentally investigated in order to study the endmill operation of fiber reinforce epoxy composites. Followings are main finding from the experimental results. First, the cutting and bending force in groove processing of the carbon fiber epoxy composite increased as the spindle speed deceased. They also deceased as the table feed increased. Second, the good cutting status obtained at the entrance of groove while delamination occurred at the exit of groove, Third, the regular high speed steel endmill was not efficient, thus the new endmill such as coated carbide rooter endmill or dia-mode endmill should be used for the effective endmll operation of carbon filber epoxy composites.