• Journal of Power Electronics
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• 제12권1호
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• pp.215-222
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• 2012

Lighting represents a significant component of commercial buildings, particularly office buildings. Fluorescent lighting is invariably used in all commercial, industrial and residential areas. A significant amount of lighting energy is wasted every day by leaving the lights on and not utilizing daylight energy. However, if daylight illuminance can be harnessed, this will reduce the electricity consumption of fluorescent lamps and save energy. This paper explains possible significant savings in lighting energy consumption and hence in costs, without reducing the performance and visual satisfaction in office or industrial buildings. It is proposed to obtain energy saving by reducing the supply voltage without degradation in lighting performance. Experimental results confirm that as much as 20% of electrical energy can be saved by reducing about 9% of the supply voltage, without noticeably affecting light output while complying with lighting standard limits.

• 한국항공운항학회지
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• 제21권1호
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• pp.39-44
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• 2013

The amount of greenhouse gas (GHG) emissions has been increasing steadily over the last 4 years, averaging 6.8 percent a year, due to the growth of low cost carriers and the increased demand for air transportations. For the aviation GHG reduction, various fuel saving activities are implemented in many areas such as high-efficiency aircraft and bio-fuel development in the technical part and low carbon flight procedures, short cut route development in the operational approach. Among the various reduction technologies, we focused on low carbon flight procedures that are crucial to GHG reduciton and suggested a reduction effect according to target implementation rate using by fuel saving estimation data in each aircraft type.

• 소성∙가공
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• 제17권8호
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• pp.662-667
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• 2008

Because of steep rise of international energy cost in recent years, high efficiency has been emphasized in energy policy. As far as injection molding machine is concerned, hybrid method using hydraulic and electric systems became the key to this energy saving. The energy saving and molding reproducibility of hybrid injection molding process were shown experimentally. The power consumption of hybrid injection molding machine is reduced to 38% as compared with that of hydraulic machine. Furthermore, the molding reproducibility was shown for both methods.

• Journal of Communications and Networks
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• 제7권2호
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• pp.126-134
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• 2005

Reducing energy consumption in mobile hosts (MHs) is one of the most critical issues in wireles/mobile networks. IP paging protocol at network layer and power saving mechanism (PSM) at link layer are two core technologies to reduce the energy consumption of MHs. First, we investigate the energy efficiency of the current IEEE 802.11 power saving mechanism (PSM) when IP paging protocol is deployed over IEEE 802.11 networks. The result reveal that the current IEEE 802.11 PSM with a fixed wakeup interval (i.e., the static PSM) exhibits a degraded performance when it is integrated with IP paging protocol. Therefore, we propose an adaptive power saving mechanism in IEEE 802.11-based wireless IP networks. Unlike the static PSM, the adaptive PSM adjusts the wake-up interval adaptively depending on the session activity at IP layer. Specifically, the MH estimates the idle periods for incoming sessions based on the exponentially weighted moving average (EWMA) scheme and sets its wake-up interval dynamically by considering the estimated idle period and paging delay bound. For performance evaluation, we have conducted comprehensive simulations and compared the total cost and energy consumption, which are incurred in IP paging protocol in conjunction with various power saving mechanisms: The static PSM, the adaptive PSM, and the optimum PSM. Simulation results show that the adaptive PSM provides a closer performance to the optimum PSM than the static PSM.

• 전기학회논문지
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• 제64권1호
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• pp.171-175
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• 2015

In this paper, because of global environmental problems such as energy shortage and abnormal climate, green energy development and energy saving technology development is being magnified. Heat insulation, the most basic and traditional energy saving method, is highly expected. Especially, simple and advanced heat insulation technique based on Nano material is promising future technology. The railway system also requires heat insulation. Especially, traditional heat insulator such as glass wool has been adopted frequently to rolling stock. The heat insulator is also adopted in general railway service buildings. Take account of cost-effective heat blocking performance, the heat insulator shall be adopted in diverse fields such as electric power, railroad, signal and communication. The only and direct solution for this problem is installing heat insulator with outstanding endurance, corrosion resistance and heat resistance to block outer heat Upgrading heat specification of equipment can be a solution, but since price and maintenance cost rise severely, this plan might be incongruous. In this research, energy saving effect of ultrathin heat insulator film was demonstrated by installing the film on roof of electrical room.

• 한국기후변화학회지
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• 제7권3호
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• pp.341-349
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• 2016

This study is intended to set a greenhouse gas emission scenario based on green remodeling pilot project (Annex building of Seoul Customs Office) using LEAP model, a long-term energy plan analysis model, to calculate the energy saving and greenhouse gas emission till year 2035 as well as to analyze the effect of electric power saving cost. Total 4 scenarios were made, Baseline scenario, assuming the past trend is to be maintained in the future, green remodeling scenario, reflecting actual green remodeling project of Seoul Customs Office, behavior improvement and renewable energy supply, and Total scenario. According to the analysis result, the energy demand in 2035 of Baseline scenario was 6.1% decreased from base year 2013, that of green remodeling scenario was 17.5%, that of behavior improvement and renewable energy supply scenario was 21.1% and that of total scenario was 27.3%. The greenhouse emission of base year 2013 was $878.2tCO_2eq$, and it was expected $826.3tCO_2eq$, approx. 5.9% reduced, in 2035 by Baseline scenario. the cumulative greenhouse gas emission saving of the analyzing period were $-26.5tCO_2eq$ by green remodeling scenario, $2.8k\;tCO_2eq$ by behavior improvement and renewable energy supply scenario, and $2.0k\;tCO_2eq$ by total scenario. In addition the effect of electricity saving cost through energy saving has been estimated, and it was approx. 634 million won by green remodeling scenario and appro. 726 million won by behavior improvement and renewable energy supply scenario. So it is analyzed that of behavior improvement and renewable energy supply scenario would be approx. 12.7% higher than that of green remodeling scenario.

• Journal of Advanced Marine Engineering and Technology
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• 제38권9호
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• pp.1057-1063
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• 2014

국제사회가 관심을 가지고 있는 이산화탄소 배출 감소를 위해 많은 연구 기관들이 연료 절감 방법을 연구하여 결과를 제시하고 있다. 비용 절감이 최종 결론이지만 아직까진, 어떻게 제시된 방법이 작동되는가, 어떠한 효과가 있는가, 어떠한 크기의 배에 가장 이상적이며 효과가 클까 등등 많은 의문점들이 제기되고 있다. 선주와 운영자들에게는 연료비가 가장 큰 비용 중 하나이다. 그리고 연료 절감은 선주나 운영자들에게는 비용 절감과 동시에 이산화탄소를 줄이는 가장 좋은 방법이다. 본 논문은 추진 효율을 높여 연료를 절감하는 방법 및 투자되는 비용과 일 년 동안 운항 후 얻어지는 연료비 절감을 통하여 투자금 회수 기간을 대략적으로 계산을 할 수 있도록 하고, 각 방법 간의 미치는 영향에 대하여 소개를 하고자 한다.

• 전기학회논문지
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• 제65권7호
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• pp.1151-1160
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• 2016

In recent years, the energy storage systems such as LiB, NaS, RFB(Redox-Flow Battery), Super- capacitor, pumped hydro storage, flywheel, CAES(Compressed Air Energy Storage) and so on have received great attention as practical solutions for the power supply problems. They can be used for various purpose of peak shaving, load leveling and frequency regulation, according to the characteristics of each ESS(energy storage system). This paper will focus at 1 MWh RFB system, which is being developed through the original technology project of energy material. The output of ESS is mainly characterized by C-rate, which means that the total rated capacity of battery will be delivered in 1 hour. And it is a very important factor in the ESS operation scheduling. There can be several options according to the operation intervals 15, 30 and 60minutes. The operation scheduling is based on the optimization to minimize the daily electricity cost. This paper analyzes the cost-saving effects by the each operating time-interval in case that the RFB ESS is optimally scheduled for peak shaving and load leveling.

• 한국유통학회지:유통연구
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• 제2권1호
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• pp.143-174
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• 1997

The model applied in this paper is based on the theory of economic order quantity (EOQ). EOQ model is introduced to explain the improvement of the transaction efficiency through the cooperative purchase. We examine explicitly how horizontal cooperation affects vertical transactions. A result of the analysis is that a seller can prefer transacting with a cooperative rather than with each buyer separately, even if he reduces the selling price of the product. Without increasing the demand for the product, this result is that dealing with a cooperative, rather than separately with each buyer, decreases the transaction cost for the seller-buyers system, the cost reduction more than off-setting the effect of price decrease on the sellers profit. For a coopative consisting of any number of buyers, Pareto efficient ordering policies that maximize the joint cost saving for the seller-buyers system are identified. We then discuss the conditions under which a cooperative under consideration can be modified to increase efficiency gain. Next, we relax the assumption that all buyers participate in a single cooperative and examine the issue of how many cooperatives, each consisting of a subset of the buyers, should be formed to maximize the total cost saving for the seller-buyers system. Finally, the issue of shapley value to divide the cooperatives gain among its members is discussed.

• 수산해양기술연구
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• 제48권4호
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• pp.360-369
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• 2012

The main purpose of this study is to analyse economic feasibility of low-carbon-oriented trawl gear. The results of benefit/cost analysis showed that use of the low-carbon fishing gear is economically feasible. Considering the fuel saving and relatively low $CO_2$ emission by reducing the resistance of gear, net present value by such gear improvement was estimated about 2,430~2,853 million won with the benefit-cost ratio 1.65~1.84 and the internal rate of return 29.18~30.48 percent. Development of low-carbon trawl gear would render significant contributions to reducing $CO_2$ emission in fishing operations and lead to reduce fishing costs due to fuel savings.