• 상하수도학회지
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• 제14권1호
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• pp.99-107
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• 2000

In this article, the removal of surfactant by ozone and BAC was studied. Batch and pilot tests were carried out for these studies. In batch tests, efficiency of ozone oxidation process was evaluated for LAS(Linear Alkylbenzen Sulfonate) and SLS(Sodium Lauryl Sulfate) removal. Under oxidant conditions, the removal of LAS was more effective than that of SLS. The removal of surfactant was more enhanced with increasing pH in oxidant systems. Pilot tests are carried out with BAC single process and ozone oxidation/BAC combined process. The removal of LAS was more effective in ozone oxidation/BAC combined process than BAC single process about 10-20%. In the case of SLS, the efficiency of BAC single process was similar to that of ozone oxidation BAC combined process. According to temperature, the removal efficiency of SLS changed from 70% to 95% and initial concentration of surfactant had no effects on removal efficiency of SLC under applied temperature above $15^{\circ}C$.

• 한국정보통신학회논문지
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• 제10권6호
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• pp.1060-1064
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• 2006

센서를 통해 수집된 데이터는 모든 정보를 취합하는 기지국으로 전송되게 된다. 센서들은 데이터를 전송하면서 지속적으로 주변 환경에 대한 데이터를 수집하여야 하기 때문에 에너지 소모가 크다. 본 논문에서는 수집된 데이터가 효율적으로 전송되어 트래픽 혼잡을 피하면서 에너지 효율성을 고려하는 기법을 제안한다. 트래픽이 증가하거나 감소할 때 전송률을 제어함으로써 Traffic 혼잡을 피하고, 기본적인 CSMA(Carrier Sense Multiple Access) 프로토콜에 최적의 옵션을 설정하여 각 센서에서 에너지 소모를 최소화는 기법이다. 시뮬레이션을 통해 최적의 CSMA 옵션과 제안된 트래픽 제어 기법을 적용하여 성능을 분석하고, 에너지 효율성과 효과적인 트래픽 제어 방법을 제시한다.

• 환경위생공학
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• 제11권3호
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• pp.37-46
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• 1996

In this study, the effect of pH, Temp, dye concentration, distance of electrode, and the potential on the removal efficiency of dye-wastewater using electrochemical reaction were investigated. Optimum conditions for the electrochemical treatment of dye-wastewater were obtained that pH;7, 8V, electrode distance; 1cm and the reaction time for obtaining above 99% removal efficiency were 10 - 40min at each conditions, From this result, we can determine the instantaneous current efficiency and specific energy consumption, and we can provide the effective data for economical treatment of industrial dye-wastewater.

• 산업경영시스템학회지
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• 제31권2호
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• pp.94-103
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• 2008

This study measured technology transfer efficiency for public institutes. The study made use of DEA being one of the non-parametric linear programming to evaluate technology transfer efficiency for public institutes and to measure technology efficiency, pure technical efficiency and scale efficiency. The measurement of the technology transfer efficiency for public institutes was as follows: The cause of the technology transfer inefficiency was affected by pure technical inefficiency more than by scale inefficiency. Public institutes' RTS(Return To Scale) value varied depending upon the features of the organizations than the features of the regions. Public research institutes' RTS value is more effective than universities' RTS value. We compared the RTS group with the RTS of Projected DMU groups. The RTS group had constant returns to scale effect while the RTS of the Projected DMU had increasing returns to scale effect. The technology transfer efficiency of public institutes varied depending upon the features of the organizations and regions : The technology transfer efficiency of public institutes were as follows : public research institutes at the metropolitan area, public research institutes at the local areas, universities at the metropolitan area and universities at the local areas. In other words, the technology transfer efficiency was affected by organizational characteristics more than by regional characteristics at the place where public institutes were located.

• The Korean Journal of Ceramics
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• 제4권3호
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• pp.240-244
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• 1998

The analytical method was developed to calculate efficiency of densifying carbon/carbon (C/C) composites using coal tar pitch as a matrix precursor at each cyle. Three factors were defined in analyzing the densification process: impregnation efficiency, retention efficiency, and overall densification efficiency. The relationships developed were applied to the experimental results for three densification cycles of C/C composites with pitches as an impregnant to evaluate the factors which may depend on the impregnant and on the route of carbonization. The impregnation efficiency increased with the repeated process cycles whereas the retention efficiency decreased irrespective of the impregnant and carbonization route. Carbonization route P+A+G, in which pressure carbonizationl (P) and graphitization (G) were done before after atmospheric pressure carboniztion (A) respectively, using impregnant of high carbon yields was the most effective method in densifying C/C composites.

• International Journal of Railway
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• 제1권2호
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• pp.37-44
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• 2008

Safe, fast, efficient and effective railway is a main factor of economic development level of every country. This paper uses the DEA method to evaluate and compare the efficiency of 12 Regions of RAI. In addition, we introduce the reference(s) unit(s) for every inefficient region, and determine the amount of input decrease and/or output increase need to become them efficient. Findings indicate that in 2006, 4 regions of 12 are in Constant Return to Scale (CRS) status and 7 of them in Variable Return to Scale (VRS), and the average efficiency is 0.730 and 0.888, respectively. In other words, RAI works 27 percent under its capacity. More over results indicate that Hormozgan, Khorasan, Tehran and Isfahan Regions have the most efficiency respectively. The results show that the 8 regions, have been working in Increaser Return to Scale and 4 reminder Regions in Decrease Return to Scale. According to this results, we submit the suitable suggestion for improve the efficiency of the inefficient regions.

• 한국항해항만학회지
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• 제41권5호
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• pp.319-328
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• 2017

The efficiency of port operations is an important indicator of port development. Moreover, there is excess handling capacity in Chinese ports, which results in a slower speed of development. Under the detrimental environment of the international shipping market, it is necessary to improve the operation efficiency of ports for long-term development. This paper provides an assessment of the competitiveness of Chinese seaport companies using the Boston Consulting Group's matrix, and efficiency measurements using a data envelopment analysis and the Malmquist method. This analysis showed that highly efficient companies reformed their development strategies, which should be a solution considered by less efficient companies, such as Shenzhen Yan Tian Port Holdings Co., Ltd.. Although, having high throughput should be reformed in the investment structure. This research will assist port companies in gaining effective operating experience, and governments in establishing strategic planning to enhance the efficiency of port development.

• 토지주택연구
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• 제11권1호
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• pp.95-101
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• 2020

In the past few decades, the global population growth and rapid economic development have resulted in significant increases in building energy consumption. To reduce greenhouse-gas emissions and building energy consumption, building materials and energy technologies must be optimized. Building retrofitting is a more efficient method than reconstruction to improve the building energy performance. In order to improve the energy performance of existing buildings, this study proposed energy-efficiency retrofit plans and derived cost-effective retrofit plan. The energy efficient retrofit method is achieved through the packaging of energy technology and the energy and cost reduction effect of the energy efficiency retrofit package are analyzed. As a result of the study, the energy-efficiency retrofit package showed an energy reduction effect of up to 60% or more and a construction cost reduction of about 30%. This study argues that optimal energy and construction cost reduction of existing buildings are possible through the packaging of energy efficiency technology.

• 조명전기설비학회논문지
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• 제21권4호
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• pp.88-95
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• 2007

Korea is highly dependent on foreign countries for energy while at the same time having a high energy-consumption industrial structure. Therefore, logical improvements in energy use efficiency and nationwide energy saving are becoming more and more important in coping with the worldwidehigh oil prices and environmental issues such as listed in the Kyoto Protocol to the United Nations Framework Convention on Climate Change. Consequently, a study was conducted on the average annual load factor in domestic areas to set a reasonable and reliable technology standard plan for high-efficiency transformers. The average annual load factor in Korea was discovered to be 18.4[%] classified by industry. This factor is expected to be used in arranging a domestic standard for a minimum efficiency system for transformers, and in reviewing and supplementing the standard transformers plan for the High Energy-Efficiency Appliance Certification. The expected effect from the establishment of the technology standards plan for highly efficient transformers is the expansion of the manufacturing and distribution of highly efficient transformers that are suitable for domestic use. These will lead to electricity cost savings for users, strengthening the related industries' market competitive powers and the effective reduction of greenhouse gases on a national level by drastically reducing loss from transformers, which accounts for a large portion of the total electric supply losses.

• Architectural research
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• 제18권2호
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• pp.59-64
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• 2016

Since the massive power outages that hit across the nation in September 2011, a growing imbalance between energy supply and demand has led to a severe backup power shortage. To overcome the energy crisis which is annually repeated, a policy change for deriving energy supply from renewable energy sources and a demand reduction strategy has become essential. Buildings account for 18% of total energy consumption and have great potential for energy efficiency improvements; it is an area considered to be a highly effective target for reducing energy demand by improving buildings' energy efficiency. In this regard, retrofitting buildings to promoting environmental conservation and energy reduction through the reuse of existing buildings can be very effective and essential for reducing maintenance costs and increasing economic output through energy savings. In this study, we compared the energy reduction efficiency of national power energy consumption by unit production volume based on thermal power generation, renewable energy power generation, and initial and operating costs for a building retrofit. The unit production was found to be 13,181GWh/trillion won for bituminous coal-fired power generation, and 5,395GWh/trillion won for LNG power generation, implying that LNG power generation seemed to be disadvantageous in terms of unit production compared to bituminous coal-fired power generation, which was attributable to a difference in unit production price. The unit production from green retrofitting increased to 38,121GWh/trillion won due to the reduced energy consumption and benefits of greenhouse gas reduction costs. Renewable energy producing no greenhouse gas emissions during power generation and showed the highest unit production of 75,638GWh/trillion won, about 5.74 times more effective than bituminous coal-fired power generation.