• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 하계학술대회 논문집 B
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• pp.964-966
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• 2003

The three-phase induction motor is rugged, reliable, long-lived, self-starting, smooth-running. But it is relatively inexpensive and three-phase power in not available everywhere, so if possible we need single-phase motor with the same characteristics. In fact, single-phase induction motors have excellent characteristics and outnumber the three-phase variety. Most of the small electric motors used in home, farm, or office are single-phase induction motors of one type or another. This electric motors application field need most energy saving type drive according to enlargement of electronic goods and to tend high class. The paper is proposed a various phase control methods for energy saving of single- phase induction motor. The controllers that are embodied by each method can use by various usage according to each performance and it is considered that application may help in the electrical energy saving because is possible to other electrical appliances.

• 한국전기전자재료학회논문지
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• 제22권11호
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• pp.918-924
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• 2009

In this paper, we designed micro-structured electromagnetic transducers for energy harvesting and verified the performance of proposed transducers using finite element analysis software, COMSOL Multiphysics. To achieve higher energy transduce efficiency, around the magnetic core material, three-dimensional micro-coil structures with high number of turns are fabricated using semiconductor fabrication process technologies. To find relations between device size and energy transduce efficiency, generated electrical power values of seven different sizes of transducers ($3{\times}3\;mm^2$, $6{\times}6\;mm^2$, $9{\times}9\;mm^2$, $12{\times}12\;mm^2$, $15{\times}15\;mm^2$, $18{\times}18\;mm^2$, and $21{\times}21\;mm^2$) are analyzed on various magnetic flux density environment ranging from 0.84 T to 1.54 T and it showed that size of $15{\times}15\;mm^2$ device can generate $991.5\;{\mu}W$ at the 8 Hz of environmental kinetic energy. Compare to other electromagnetic energy harvesters, proposed system showed competitive performance in terms of power generation, operation bandwidth and size. Since proposed system can generate electric power at very low frequency of kinetic energy from typical life environment including walking and body movement, it is expected that proposed system can be effectively applied to various pervasive computing applications including power source of embodied medical equipment, power source of RFID sensors and etc. as an secondary power sources.

• 한국지열·수열에너지학회논문집
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• 제19권4호
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• pp.18-26
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• 2023

Green-remodeling is to improve the energy performance of existing buildings that have been aged for more than 15 years since completion. In order to achieve the national greenhouse gas emission reduction plan in the building sector, it is necessary to analyze the carbon reduction effect by considering the internal carbon emissions that may occur during green-remodeling of old buildings. This study analyzed the effects of energy reduction and carbon emission reduction when green-remodeling was applied to old health centers constructed in 1992. When applying green-remodeling, the carbon emission reduction effect considered the embodied carbon emission of the improvement items and the carbon emission at the building operation stage. When applying green-remodeling to existing buildings, energy consumption was reduced by 39.3%, and carbon emissions were reduced by 48.9% after 27 years of green-remodeling. In order to reduce carbon emissions, it was important to apply a renewable system as an item to improve the performance of green-remodeling. In particular, it was confirmed that it is very important to consider the photovoltaic system as a top priority for the carbon emission reduction.

• World Technopolis Review
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• 제8권1호
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• pp.59-70
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• 2019

Where is a better place to live? In the coming era, this should be more than simply a livable place. It should be an adaptable place that has a flexible system adaptable to any new situation in terms of diversity. Customization and real-time operation are needed in order to realize this technologically. We expect a smart city to have a flexible system that applies technologies of self-monitoring and self-response, thereby being a promising city model towards being a better place to live. Energy demand and supply is a crucial issue concerning our expectations for the flexible system of a smart city because it is indispensable to comfortable living, especially city living. Although it may seem that energy diversification, such as the energy mix of a country, is a matter of overriding concern, the central point is the scale of place to build grids for realizing sustainable urban energy systems. A traditional hard energy path supported by huge centralized energy systems based on fossil and nuclear fuels on a national scale has already faced difficult problems, particularly in terms of energy flexibility/resilience. On the other hand, an alternative soft energy path consisting of small diversified energy systems based on renewable energy sources on a local scale has limitations regarding stability, variability, and supply potential despite the relatively light economic/technological burden that must be assumed to realize it. As another alternative, we can adopt a holonic path incorporating an alternative soft energy path with a traditional hard energy path complimentarily based on load management. This has a high affinity with the flexible system of a smart city. At a system level, the purpose of all of the paths mentioned above is not energy itself but the service it provides. If the expected energy service is fixed, the conclusive factor in choosing a more appropriate system is accessibility to the energy service. Accessibility refers to reliability and affordability; the former encompasses the level of energy self-sufficiency, and the latter encompasses the extent of energy saving. From this point of view, it seems that the small diversified energy systems of a soft energy path have a clear advantage over the huge centralized energy systems of a hard energy path. However, some insuperable limitations still remain, so it is reasonable to consider both energy systems continuing to coexist in a multiplexing energy system employing a holonic path to create and maintain reliable and affordable access to energy services that cover households'/enterprises' basic energy needs. If this is embodied in a smart city concept, this is nothing else but smart energy inclusion. In Japan, following the Fukushima nuclear accident in 2011, a trend towards small diversified energy systems of a soft energy path intensified in order to realize a nuclear-free society. As a result, the Government of Japan proclaimed in its Fifth Strategic Energy Plan that renewable energy must be the main source of power in Japan by 2050. Accordingly, Sony vowed that all the energy it uses would come from renewable sources by 2040. In this situation, it is expected that smart energy inclusion will be achieved by the Japanese version of a smart grid based on the concept of a minimum cost scheme and demand response.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권4호
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• pp.467-472
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• 2012

In this paper, we present a finite element method (FEM) study on the space charge effects in organic light emitting diodes. The physical model covers all the key physical processes in OLEDs, namely charge injection, transport and recombination, exciton diffusion, transfer and decay as well as light coupling, and thin-film-optics. The exciton model includes generation, diffusion, and energy transfer as well as annihilation. We assumed that the light emission originates from oscillation which thus is embodied as exciton in a stack of multilayer. We discuss the accumulation of charges at internal interfaces and their signature in the transient response as well as the electric field distribution. We also report our investigation on the influence of the insertion of the emission layer (EML) in the bilayer structure.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.999-1002
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• 2003

In this study, the white organic light emitting device was fabricated using ITO/a-NPD:DCM/a-NPD/BCP/Alq3/Al structure. Blue emission by a-NPD and orange emission by energy transfer between a-NPD and DCM embodied the white emission. The optimal structure of the white OLED is ITO/a-NPD:DCM(50$\square$)/a-NPD(150$\AA$)/BCP(100$\square$)/Alq$_3$(200$\square$)/Al. We varied the doping concentration of DCM properly and obtained high purity white emitting light. The CIE coordinate and maximum luminance of the devices was obtained (0.310, 0.333) and 400cd/$m^2$ at 11Volt.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.348-350
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• 2006

Currently the indication method of the traffic signal light which is established in our country displays each "red, yellow, green" using the brightness LED signal light. In this paper, one LED circular arrangement replaces the Current indication method of the traffic signal light using two color LED. Also the blinking signal function of present time uses the MCU of AVR series and it is embodied with magnification and abridgment of the circular arrangement for recognizing easily far away. The signal light indication method which is proposed will be able to substitute the signal light of 3 colors with 1 signal light with economic profit presented the reform measure of energy efficiency improvement together.

• Computers and Concrete
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• 제11권6호
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• pp.571-585
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• 2013

Asymmetrical reinforcement for circular sections in wall piles is an efficient construction component with reduced embodied energy. It has been proven that asymmetrical reinforced wall piles may save more than 50% of the reinforcement than the traditional symmetrically reinforced circular sections. The use of this new type of structural member increases the number of variables in the design problem, which makes its use by engineers more complicated. In order to facilitate the use of the asymmetrically reinforced piles, this paper presents a criterion for the design of this type of structural member. The chosen criterion has been analyzed with the help of flexural capacity-cost curves. The new criterion is similar to the design procedure traditionally used for RC beams.

• 한국산학기술학회논문지
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• 제7권5호
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• pp.963-969
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• 2006

본 연구에서는 태양광 발전시스템의 최대전력추종을 위해 퍼지 이론을 도입한 디지털 퍼지제어기를 설계하였다. 그리고 퍼지제어기의 디지털 설계를 위해 소용량 태양광 발전시스템의 각 부분을 구성하고 이를 적용하여 기존의 제어기와 비교 실험하였다. FPGA로 구현된 제어기는 기존의 마이크로프로세서로 구현된 제어기에 비해 일사량 변화에도 출력전압의 변동이 적은 안정적인 동작특성을 보였다.

• KIEAE Journal
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• 제1권1호
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• pp.11-16
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• 2001

Concern about global environment has been increasing in recent years. Efforts to minimize the environmental impact to the globe as well as human beings have increased, especially in the late twentieth century. The study researches one of the solutions for the environmentally friendly building construction, which can contribute to sustaining the world environment. Assessment and proposals are made for high-rise apartments, one of the most popular construction types nowadays in Korea. Careful building design and construction for apartment buildings could reduce the environmental impact significantly without lowering standards of living. Since the volume of high-rise apartment construction is so great, a small improvement in each building will make a great contribution. Assessments are made over the life-span of apartment buildings. A tool has been made through references from western examples. mainly from BHEEAMs made in the United Kingdom. The components of the tool include passive design strategies, building materials. energy consumption during building operation, and management and maintenance. Co-relationship between buildings and ten environment in Korea is searched. Korean high-rise apartments are assessed with the tool and suggestions for sustainable development are made mainly for improvement of embodied energy of building materials and the life of buildings.