• Journal of Construction Engineering and Project Management
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• 제3권3호
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• pp.10-16
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• 2013

The annual expenditure on diesel oil and heavy oil in the construction sector is the second largest among all industrial sectors. According to the greenhouse reduction scheme of Korean Government, construction sector targeted 7.1% reduction by 2020. Although this target is not higher than other industrial sectors, it is not easy to achieve the reduction target without radical advance in technology, which cannot be expected to happen soon, considering the conservative characteristics of construction industry. Most researches on environmental issues focus on the issues related to energy saving matters during material production stage or maintenance stage, such as heating and insulation, and few deal with the issues directly related to the energy use in the construction sites. This research regards the operation of equipment for the on-site construction processes as a system and attempts to model the energy use processes related to the activities in construction sites, and provides simulation results of earth excavation and hauling processes. The result of this research is expected to aid construction planners estimating the time-based patterns of energy use and assessing greenhouse gas emission and to help selecting more energy efficient alternatives at the planning stage.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.735-737
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• 2017

An Off grid or remote solar electric systems are an energy supply to our home or to our companies without the utility of Grid at all. Off grid solar systems are very important for those who live in remote locations especially for developing countries where getting the electric grid is extremely expensive, inconvenient or for those who doesn't need to pay a monthly bill with the electric bill in general. The main critical components of any solar power system or renewable energy harvesting systems are the energy storage systems and its charge controller system. Energy storage systems are the essential integral part of a solar energy harvesting system and in general for all renewable energy harvesting systems. To provide an optimal solution of both high power density and high energy density at the same time we have to use hybrid energy storage systems (HESS), that combine two or more energy storage technologies with complementary characteristics. In this present work, design and simulation we use two storage systems supercapacitor for high power density and lithium based battery for high energy density. Here the system incorporates fast-response supercapacitors to provide power to manage solar smoothing and uses a battery for load shifting. On this paper discuss that the total energy throughout of the battery is much reduced and the typical thermal stresses caused by high discharge rate responses are mitigated by integrating supercapacitors with the battery storage system. In addition of the above discussion the off grid solar electric energy harvesting presented in this research paper includes battery and supercapacitor management system, MPPT (maximum power point tracking) system and back/boost convertors. On this present work the entire model of off grid electric energy harvesting system and all other functional blocks of that system is implemented in MATLAB Simulink.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.177-182
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• 2009

The purpose of this study is to investigate planning of urban energy supply systems configuration and operating conditions for the district heating and cooling system using combined heat and power system. Generally the district heating and cooling system has been known to one of the effective way for energy saving, cost reduction and demand side management of energy. Economical analyses were carried out and operating characteristics for some systems were examined in terms of GER factor which represents to the ratio of gas and electricity costs. Rates of the energy consumption and the $CO_2$ emission were compared from the system configuration of the energy supply system with new district cooling system with the conventional one.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.540-543
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• 2015

Solar energy is one of the most important alternative energy sources which have been shown to meet high levels of heating and cooling demands in buildings. However, the efficiencies to satisfy these demands using solar energy significantly vary based on the characteristics of individual building. Therefore, this paper is focused on developing the methodology which can help to design optimal solar system for heating and cooling to be in cooperated within the existing buildings according to their load profiles. This research has established the Solar Heating and Cooling (SHC) system which is composed of collectors, absorption chiller, boiler and heat storage tank. Each component of SHC system is analyzed and made by means of Modelica Language and Pistache tool is verified the results. Sequential approximate optimization (SAO) and meta-models determined to 15 design parameters to optimize SHC system. Finally, total coefficient of performance (COP) of the entire SHC system is improved approximately 7.3% points compared to total COP of the base model of the SHC system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 D
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• pp.2254-2256
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• 2004

Korea Water Resources Corporation (KOWACO), the only organization specialized in water resources management in Korea, is planning to establish a centralized control system for a related operation. in the central control room, of decision making as to water management and electric power generation. This plan is intended to convert the existing on-site operation system in each multi-purpose dam across the nation into a central operation system in the Corporations head office, for which Generation Integrated Operating System (GIOS) will be established control center in the Corporations head office and modernized nine (9) power stations. substations (RDAC). This article discusses realization of GTOS, especially real-time operation of hydropower plants and a specific architectural features for system communication.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권3호
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• pp.1345-1362
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• 2019

Most active queue management algorithms manage network congestion based on the size of the queue but ignore the network environment which makes queue size change. It seriously affects the response speed of the algorithm. In this paper, a new AQM algorithm named CT-AQM (Change Trend-Adaptive Queue Management) is proposed. CT-AQM predicts the change trend of queue size in the soon future based on the change rate of queue size and the network environment, and optimizes its dropping function. Simulation results indicate that CT-AQM scheme has a significant improvement in loss-rate and throughput.

• 풍력에너지저널
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• 제14권1호
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• pp.44-51
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• 2023

Some controllers have been introduced in various studies to mitigate the negative effects of renewable sources. These have been modified to fit a formed solution in various ways. This paper deals with the voltage regulation of wind farms in voltage dip situations where communication failures occur. The aim is to discuss the modification of the online wind farm management system. To discuss modifications of the online wind farm management system, we focus on voltage regulation of wind farms when communication failures occur. The structure has been designed to respond to a voltage drop when the outer reference is absent due to communication errors. Since the loss reduction effect has been maintained in the designed case studies, it can be derived that the proposed method can respond to voltage drops, along with a used objective function.

• Nuclear Engineering and Technology
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• 제41권4호
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• pp.477-492
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• 2009

In this paper, we discuss the experiences during the preparation of the Wolsong Low- and Intermediate-Level Radioactive Waste Disposal Center. These experiences have importance as a first implementation for the national LILW disposal facility in the Republic of Korea. As for the progress, it relates to the area of selected disposal site, the disposal site characteristics, waste characteristics of the disposal facility, safety assessment, and licensing process. During these experiences, we also discuss the necessity for new organization and change for a radioactive waste management system. Further effort for the safe management of radioactive waste needs to be pursued.

• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1729-1738
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• 2014

The offline verification of state of charge estimation, power estimation, fault diagnosis and emergency control of battery management system (BMS) is one of the key technologies in the field of electric vehicle battery system. It is difficult to test and verify the battery management system software in the early stage, especially for algorithms such as system state estimation, emergency control and so on. This article carried out the virtual environment modeling for verification of battery management system. According to the input/output parameters of battery management system, virtual environment is determined to run the battery management system. With the integration of the developed BMS model and the external model, the virtual environment model has been established for battery management system in the vehicle's working environment. Through the virtual environment model, the effectiveness of software algorithm of BMS was verified, such as battery state parameters estimation, power estimation, fault diagnosis, charge and discharge management, etc.

• 전자공학회논문지
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• 제52권1호
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• pp.155-161
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• 2015

스마트 그리드 확산사업으로 에너지 저장시스템의 보급이 활발히 이루어지고 있다. 대규모 EES(Electric Energy Storage system)의 경우 수용가에 설치된 BEMS(Building Energy Management System) 또는 BAS(Building Automation System)등과 연동하여 효율적인 제어가 가능하나 일반 주택에 설치되는 EES는 운전 및 제어를 위한 전문 인력이 없어 이를 원격에서 통합관리할 수 있는 시스템이 필요하다. 또한, 태양광 발전과 EES가 동시에 설치된 경우 태양광 발전이나 전력부하에 따라 효율적인 제어를 할 수 있는 소규모의 EMS(Energy Management System)가 필요하게 된다. 본 논문에서는 주택에 설치된 태양광 발전과 EES를 효율적으로 제어하기 위한 EMS를 구현하고 그 유용성을 실험을 통해 확인하였다.