• Journal of ILASS-Korea
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• v.23 no.4
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• pp.175-184
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• 2018

Emission characteristics of regulated (NOx, PM, CO, NMHC) and unregulated (VOCs, aldehydes, PAHs) air pollutants were investigated for diesel heavy duty buses equipped with different after-treatment systems (DPF+EGR and SCR) under urban driving cycle. The combustion temperature and the working temperature of SCR catalysts were important to make impact on NOx emissions, whereas PM emissions were low. The alkane groups dominated NMVOCs emissions, making 42.6~59.4% of sum of the NMVOCs emissions. Especially, alkane emissions of DPF+EGR-equipped vehicle included DOC had 14.9~15.5% higher than those of SCR-equipped vehicle due to low efficiency of oxidation catalyst. In the case of individual NMVOCs, n-nonane and propylene emissions highly occupied for DPF+EGR and SCR, respectively. Formaldehyde emissions among aldehydes were the highest and PAHs emissions were hardly detected except naphthalene and phenanthrene. The NMHC speciation has been shown to be the highest of the formaldehyde ranged 20.8~21.5%. The results of this study will be contributed to establish Korean HAPs emission inventory for automobile source.

• Environmental and Resource Economics Review
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• v.33 no.1
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• pp.33-57
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• 2024

This study analyzes the purchase subsidy for electric light-duty vehicles in terms of environmental benefits and total cost of ownership(TCO). For the environmental benefits, we considered the emissions from the power generation mix and reflected the change in efficiency of electric vehicles according to the temperature distribution. The environmental benefits of driving electric vehicles were estimated to be between KRW 2.2 million and KRW 5.3 million. Also, the TCO of electric vehicles compared to diesel vehicles under the current purchase subsidy was estimated to be about KRW 3.6 million lower for business use and about KRW 6.6 million lower for non-business use. These results imply that it is reasonable to lower the unit price of the purchase subsidy even within the same budget. Moreover, the remaining budget could be better spent on upgrading the charging infrastructure, which would reduce the inconvenience of charging for potential buyers.

• The KSFM Journal of Fluid Machinery
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• v.7 no.2 s.23
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• pp.21-26
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• 2004

In this study the effects of fluid viscosity on the pump performances for a conventional centrifugal pump were experimentally investigated. The study aimed to compare the pump characteristics between water and viscosity fluids. In order to measure the flow rate and pressure, v-notch welt and bourdon pressure gauges were used for the codes of KS B6301 and KS B6302. The working fluids were water, aqueous sugar and glycerin solutions. The results were summarized as follows : The experimental results were summarized as follows : the pump characteristics of the total head, shaft power, and efficiency with high viscosity fluids were different from those of water. When the viscosity of the applied fluid was increased, the total head and efficiency were more decreased than those of water. The decreasing gradients of the total head and the efficiency were larger than water due to the increased disk friction losses at the duty operation point. However, the shut-off head was almost constant regardless the viscosity of applied fluids. Each efficiency curves for the sugar $20w\%$ and glycerin $20w\%$ solutions was decreased up to $15.1\%$ and $34.4\%$ than that of water, respectively.

• The Research Journal of the Costume Culture
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• v.22 no.3
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• pp.503-510
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• 2014

Nowdays, costumer's washing behavior were often times for remove to light-duty dirt. The purpose of this study is to provide the most effective washing conditions of detergent concentration and temperature conditions for help save energy and water resources required to the washing process. Washing conditions were as follows: 2 kinds of detergents and 4 types of artificially soiled fabrics were used. Detergent concentration was 0%, -10%, and -20% below the recommended conc. of manufacturer's standard. Temperature of bath was $20^{\circ}C$ and $40^{\circ}C$. The results of this study were as follows: First, washing performances of all kind of artificially soiled fabric improved as the temperature of bath at $40^{\circ}C$. Second, the test was conducted under the condition of decreasing respectively -10% and -20% below of the recommended concentration of manufacturer's standard detergent. The average of washing efficiency was not considerably affected by the reduction of 10% below of manufacturer's standard. Third, in case of the water temperature were $20^{\circ}C$, polyester/cotton blended fiber were higher degree of washing efficiency than cotton fiber.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1997.10a
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• pp.88-92
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• 1997

Power conversion system must be increased swiching frequency in order to achieve a small size, a light weight and a low noise, However, the swiches of converter are subjected to high switching power losses and switching stresses. As a result of those, the power system brings on a low efficiency. In this paper, the authors propose a DC-DC boost converter of high power by partial resonant switch method (PRSM). The switching devices in a proposed circuit are operated with soft swiching and the control technique of those is simplified for switch to drive in constant duty cycle. The partial resonant circuit makes use of a inductor suing step up and a condenser of loss-less snubber. Also the circuit has a merit which is taken to increase of efficiency, as if makes to a regeneration at input source of accumulated energy in snubber condenser without loss of snubber in conventional cirvuit. The result is the the switching loss is very low and the efficiency of system is high. The proposed converter is deemed the most suitable for high power applications where the power switching devices are used.

• Journal of ILASS-Korea
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• v.23 no.4
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• pp.244-253
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• 2018

Recently, The ministry of Environment in korea have introduced Euro-6d temp which was strengthened at the same time as Europe. Small Light-duty passenger vehicles need the SCR system of after-treatment to meet enhanced emission regulations. However, SCR system has a low conversion efficiency in a low temperature less than 200 degree. In this study, the NOx conversion efficiency of SCR system was analyzed by installing a NOx sensors and a temperature sensors in a diesel vehicle. Also, in order to analyze the effect of the cold-start, the test was performed on the same RDE route and compared with the test of hot-start. As a result, SCR system has characteristics of low conversion efficiency under cold-start conditions.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.05a
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• pp.13-16
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• 2005

Generally, as corrosive protection processing of a steel structure, zinc galvanizing and heavy duty coating paint are applied. However, zinc galvanizing has the difficulty of restriction of a size, or on-site construction. Moreover, heavy duty coating paint has a problem with many administrative and maintenance expenses with short problem of adhesion, corrosion generating of a damage portion, and maintenance management cycle. In this study, a salt water spray test, CASS test, and the electrochemistry examination were carried out for the thermal metal spray method of construction for corrosive protection performance evaluation. Moreover, the corrosive protection life of a thermal metal spray method of construction was quantitatively calculated on the basis of this experiment. in consideration of LCC, the economical efficiency of a general corrosive protection method of construction and a thermal metal corrosive protection method of construction was compared. Consequently, although initial construction expense was estimated 16 to $30\%$ high, as for a thermal metal spray method of construction, it turns out that the administrative and maintenance expenses for 100 years became cheap 9.3 to 13 or more times.

• Journal of Power System Engineering
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• v.17 no.6
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• pp.130-135
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• 2013

It is a research about the change in reduction efficiency and performance resulting from installation of the EGR cooler, which is the core technology reducing NOx in response to standards been tightened of exhaust controls for off-road vehicle. It can reduce NOx by altering combustion temperature and oxygen concentration by recycling high-temperature exhaust gas. The target engine was large diesel engine for construction machine through by which we were able to verify a rate of change in output and capabilities for a heat-exchange within cooler itself depending on the existence of EGR cooler system. We have acquired a emission reduction technology for a construction machine by testing the reduction performance and rate of change in output.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.149-157
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• 2008

Since wireless sensor networks consist of nodes with the constrained battery, energy efficient MAC operation is one of the important issues. Low duty cycle operation is critical to conserve energy in wireless sensor network MAC protocol. Some paper proposed a new approach to low power listening, which employs a short preamble to further reduce energy consumption and to reduce latency. But short preamble suffers from unfair channel access problem since there was no consideration for contention between transmission nodes. Preamble counting proposes a solution to each of these problems by employing node selection information. Simulation results show that the preamble counting provides an improved energy efficiency and fairness of packet delivery.

• Journal of Korea Multimedia Society
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• v.16 no.11
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• pp.1348-1356
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• 2013

Disney Animation has showed not only artistic excellence but also technological innovations through a lot of animation films that they released. Especially with the unique concept that free-willed game characters dive into different worlds of games in animation film, received both critical and commercial acclaim for its stunning visuals and outstanding CG (computer graphics) effects. The purpose of this study is to analyze different styles of game worlds, Disney's layout pipeline, and in-house camera capture system used in . This paper analyzes that three game worlds in this film such as Fix-It Felix Jr., Sugar Rush, and Hero's Duty express different styles by using appropriate character animation and camera movements. Especially Hero's Duty game which new in-house camera capture system is extensively used maximizes unseen visuals by perfectly making realistic and believable game world. Disney's newly developed in-house camera capture system, which is used in this film for the first time, allows real camera's motion and shake and real-time camera's movement and correction within animation set. Result of this study proves that this system improves directing of feature animation and enhance efficiency of the layout department's production process. Therefore, it contributes to a great extent to development of animation films' business.