• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권11호
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• pp.3937-3954
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• 2014

With the increasing electricity consumption and the wide application of renewable energy sources, energy auction attracts a lot of attention due to its economic benefits. Many schemes have been proposed to support energy auction in smart grid. However, few of them can achieve range query, ranked search and personalized search. In this paper, we propose an efficient multi-keyword range query (EMRQ) scheme, which can support range query, ranked search and personalized search simultaneously. Based on the homomorphic Paillier cryptosystem, we use two super-increasing sequences to aggregate multidimensional keywords. The first one is used to aggregate one buyer's or seller's multidimensional keywords to an aggregated number. The second one is used to create a summary number by aggregating the aggregated numbers of all sellers. As a result, the comparison between the keywords of all sellers and those of one buyer can be achieved with only one calculation. Security analysis demonstrates that EMRQ can achieve confidentiality of keywords, authentication, data integrity and query privacy. Extensive experiments show that EMRQ is more efficient compared with the scheme in [3] in terms of computation and communication overhead.

• KIEAE Journal
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• 제14권3호
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• pp.23-29
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• 2014

With high acknowledgements of environmental conservation and energy saving, many architectural technologies using renewable energy have been recently applied at buildings which take about 20% of total energy consumption. Among renewable energy sources, the photovoltaic is considered as the most highly potential one due to advantages of infiniteness and cleanliness. Also, projects to install renewable energy systems have been continuously performed at deteriorated educational facilities as energy efficient remodeling projects or green school projects by the Korean government. This paper proposes appropriate capacities by school level on installing photovoltaic systems at deteriorated school buildings, based on the balance of annual electricity power demand and supply between buildings and systems. Using the Visual DOE program and Merit program, the appropriate installment capacity of photovoltaic system turned out be 40kWp at elementary school building and 60kWp at middle and high ones. In addition, annual energy use proved to be reduced by 20.2% at elementary school, 26.9% at middle school, and 21.0% at high school by installing photovoltaic systems with the appropriate capacities.

• KIEAE Journal
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• 제6권3호
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• pp.49-56
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• 2006

The roof among the outer surfaces of buildings is an optimum place to install PV since it is the best favorable part in the building to be exposed to day light. Especially, in case of module of BIPV for Roof, it should have essentially the functions of both electricity generation and roof-finish as a construction material. The followings are the results of the study which has analyzed the architectural conditions and applications thereof at the job site. -The aesthetic function of BIPV module is very important because the roof, mostly located at the top of the buildings, is easily recognized and affects outer interior design of the building a lot. -The heat proof of BIPV for Roof could affect the energy consumption through the roof having a wide area. -For architectural condition to the weather, the roof has to ensure the stability of the weather, humidity proof, and airtightness to the wind respectively. -For architectural condition of the structure, endurance by physical power such as stability of both combining and fixing and transfer of load should be ensured. -For residents protection, it has also architectural functions to secure for the space and shield ozone, UV and noxious substances. -Through its practical applications, It is already confirmed that there are various types of BIPV modules overseas and its application has been proved successfully.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.229-234
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• 2008

The new millennium has started with several innovations driven by fast evolution of the technologies in energy sector. A strong impulse towards the diffusion of new economical efficient technologies regulatory incentives related to energy production from renewable source and a small scale building trigeneration and to promotion of more sustainable environmental-friendly generation solutions, the evolution of electricity markets, more and more binding local emission constraints, and the need for improving the security of supply to reduce the energy system vulnerability. The 24 percentage energy quantify of total energy consumption consumes in commercial buildings and residential houses and the 30% portion of total $CO_2$ emissions covers also in the commercial buildings and residential houses sector. To cope with efficiently this energy sinuation in building sector, Building microgrid or building tooling, heating & power(BCHP) system has been interested in recent day due to meeting thermal and electric energy requirements efficiently and with appropriate energy quality. A multi agent system is a collective of intelligent agents that communicate with each other and work cooperatively to achieve common goals. Also, it is to medicate and coordinate communication between Control Areas and Security Coordinators for teal-time control of the BCHP system and the power pid. In this new circumstance, it is very important to integrate the power and energy delivery system and the information system(communication, networks, and intelligent equipment) that controls it. Therefore, development of smart control modules with open communication protocol and seamlessly interchange the data and information between control network and data network including extranet and intranet give a great meanings. We designed and developed the TCP/IP-CAN IED agent modules and ModBus./LonTalk/(TCP/IP) IED agent ones to configure the multi-agent system based smart energy network of commercial buildings and also intelligent algorithms for inverter fault diagnostics which ran be operated in control level or agent level network.

• Journal of Electrical Engineering and Technology
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• 제13권5호
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• pp.1917-1926
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• 2018

In view of the current state of the reserves of electric energy generated resources and the share of electric motors in electricity consumption, many researches and studies related to efficiency in electric motors are being made. The presented work is related to the Axial Flux Permanent Magnet Synchronous Motor (AF-PMSM), which has recently undergone significant work based on the development of magnet and motor technology. In this study, a novel AF-PMSM was designed analytically through Finite Element Method (FEM) which can be started by connecting to a line such as an asynchronous motor in a transient state and can operate with high efficiency and power factor after synchronization in steady state without the need for an expensive motor drive. According to the obtained FEM results, a design with an efficiency class of IE4 of 5.5 kW shaft power, a 4 poles motor was obtained. As a result, economic calculations indicate that the extra cost of the designed Line start AF-PMSM with respect to the asynchronous motor is rapidly compensated by energy saving due to a more efficient operation, especially constant speed operations. As a result of the analysis obtained, the targeted values are reached. For induction motors and radial flux permanent magnet synchronous motors, a good alternative motor that can operate with high efficiency and power factor has been obtained.

• 한국수소및신에너지학회논문집
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• 제30권2호
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• pp.136-146
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• 2019

A solid oxide fuel cell (SOFC) based hybrid desiccant cooling system model is developed to study the effect of fuel utilization rate of the SOFC on the reduction of energy consumption and $CO_2$ emission. The SOFC-based hybrid desiccant cooling system consists of an SOFC system and a Hybrid desiccant cooling system (HDCS). The SOFC system includes a stack and balance of plant (BOP), and HDCS. The HDCS consists of desiccant rotor, indirect evaporative cooler, electric heat pump (EHP), and heat exchangers. In this study, using energy load data of a commercial office building and SOFC-based HDCS model, the amount of ton of oil equivalent (TOE) and ton of $CO_2$ ($tCO_2$) are calculated and compared with the TOE and $tCO_2$ generation of the EHP using grid electricity.

• International journal of advanced smart convergence
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• 제11권3호
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• pp.222-228
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• 2022

As a means to cope with the climate change crisis caused by global warming, automobile manufacturers continue to make efforts to use the driving energy of vehicles as electricity. As a result, parts industry such as battery, motor, and controller are attracting attention. China is often seen in large cities, with electric vehicles such as electric bicycles, electric motorcycles, and small electric vehicles popularized and commercialized, mainly in large cities. However, small electric vehicles are not popular in Korea, which is why the country's topography is high in hills. In order to drive the hilly domestic roads, power performance including vehicle climbing ability should be improved. In order to improve the power performance and the climbing capacity of small electric vehicles, the capacity of the motor should be increased. However, when the performance of the motor is improved, the weight of the motor becomes heavy and the price competitiveness is likely to decrease. In addition, in order to operate a high-performance motor, the power consumption of the battery is rapidly increased, so various problems must be solved. In order to commercialize a small electric vehicle for one or two people who do not emit harmful exhaust gas to the human body in a hilly domestic terrain, it is effective to have a separate transmission system. In this study, we were conducted dynamometer test to produce a continuously variable transmission(CVT) system prototype using a spring that can be applied to a small electric vehicle and to install a CVT system prototype manufactured in a small electric vehicle. The dynamometer test results showed that the maximum speed performance, acceleration performance, and climbing performance were improved.

• 응용통계연구
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• 제32권1호
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• pp.161-171
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• 2019

일별 최대전력 수요 예측은 국가의 전력 수급운영에 중요한 과제로서 과거부터 다양한 방법들이 끊임없이 연구되어 왔다. 일별 최대전력 수요를 정확히 예측함으로써 발전설비에 대한 일일 운용계획을 작성하고 효율적인 설비 운용을 통해 불필요한 에너지 자원의 소비를 감소하는데 기여할 수 있으며 여름 겨울철 냉난방수요로 인해 발생하는 전력소비 과다로 인한 전력예비율 감소 문제 등에 선제적으로 대비할 수 있는 장점을 가진다. 이러한 일별 최대전력수요 예측을 위하여 본 논문에서는 Seasonal ARIMA, TBATS, Seasonal Reg-ARIMA, NNETAR 모형에 평일, 주말, 특수일에 대한 효과와 온도에 대한 영향을 함께 고려하여 다음날의 일별 최대전력을 예측하는 모형을 연구하였다. 본 논문을 통한 모형들의 예측 성능 평가 결과 요일, 온도를 고려할 수 있는 Seasonal Reg-ARIMA 모형과 NNETAR 모형이 이를 고려할 수 없는 다른 시계열 모형보다 우수한 예측 성능을 나타내었고 그 중 인공신경망을 활용한 NNETAR 모형의 예측 성능이 가장 우수하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제38권3호
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• pp.240-245
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• 2014

환경오염에 대한 심각성이 대두되면서 선박부문의 온실가스 배출에 관한 연구가 전 세계적으로 활발하게 진행되고 있다. 이에 반하여 국내는 아직 기초 연구수준에 그치고 있다. 본 연구에는 실습선 한바다호를 이용하여 운항 중 발생하는 온실가스를 정량적으로 조사하였고, 연료소모량과 육상전기 사용량을 바탕으로 실습선이 배출하는 온실가스를 산정하였다. 2012년 1년 동안의 실제 운항데이터에서 연료소모량과 육상전기 사용량을 기본으로 Tier 1 방법을 이용하여 온실가스를 산정하였다. 이를 통하여 선박 총톤수 1톤을 운항 유지하는데 배출되는 배출 가스량과 실습생 1명을 1년 실습시키는데 발생하는 가스량을 분석하였다. 향후 선박에서 발생하는 오염물질의 인벤토리를 지속적으로 관리하여 강화되고 있는 국제 규제에 대비해야 할 것으로 사료된다.

• KIEAE Journal
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• 제10권6호
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• pp.73-80
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• 2010

Since the Korean War, Korea has experienced modernization. The population increase by baby booming has asked for more space for educational facilities. In such a situation, the purpose of educational facilities was to accommodate continuously increasing students, rather than seeking for quantitative demands. In addition, in accordance with social changes, educational shifts were required. After the revision of the seventh national curriculum in education in 1997, the school buildings became varied. The design of buildings in accordance with educational curriculum has been improved, but still lack of forming comfortable environment and considering energy efficiency in school buildings. For the improvement of educational environments, educational media such as TV and computers have been provided, and energy systems, including heating and cooling systems, has been continuously increased. As a result, it appeared that energy use in school buildings and facilities has been steadily increased and that the structure of energy consumption has been also changed, especially with regard to electricity use. Living in the 21st century, human beings face global environmental issues, such as global warming, geographical climate changes, and ozone destruction that are the consequences of fossil energy use. Therefore, even in industrial areas, considering a counterplan for low energy use is being paid attention. Starting with Kyoto Protocol in 1992, people try to decrease carbon dioxide and to develop alternative energies (i.e. natural energy); for example, solar energy, wind force, terrestrial heat, and water power. Advanced countries already set up a criterion for $CO_2$ decrease ranging from office buildings to residential houses and also propose alternatives for the $CO_2$ decrease. However, there is no such a plan for low energy use and $CO_2$ decrease in school facilities, and any research on the actual conditions was not accomplished. Thus, this study examines energy demand in classrooms that take up a large portion of energy demand in school building structure.