• 설비공학논문집
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• 제28권3호
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• pp.115-122
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• 2016

In this study, 21 energy reduction factors were selected as architecture, system & operation, and lighting and equipment parts to analyze reduction method of the load occurring in office buildings. Energy consumption simulation was performed. In the architecture part, saving rate (1.53%) of "occupant density" factor was the most efficient. In the system and operation part, saving rate (1.28%) of "interior VAV and exterior FPU type" factor was the most efficient. In case of lighting and equipment part, saving rate (12.42%) of "schedule" factor was the most efficient. In the three parts, saving rate of the lighting and equipment part was 27.32%. This was caused by the "schedule" factor. Saving rates of the architecture part and the system and operation part were 3.39% and 1.20%, respectively.

• 한국통신학회논문지
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• 제33권4A호
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• pp.450-457
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• 2008

에너지 효율적 전송기술은 무선 PAN(WPAN: Wireless Personal Area Network) 장치들과 같이 에너지 소모에 있어서 제약을 많이 받는 무선장치의 동작 시간을 최대화하기 위해서 필수적으로 요구되는 핵심 기술이다. 더욱이, WPAN이 TDMA 동작 방식과 연동되어 수행될 때, 할당된 각 time 슬롯에서 실제 물리적 전송의 QoS 요구 사항에 대한 보장은 설계시 만족시켜야 하는 또 다른 중요 설계 고려사항이다. 따라서, 본 논문에서는 TDMA 기반의 비경합 매체 접근 프로토콜과 함께 동작하는 WPAN을 위한 에너지-효율적이며 동시에 QoS를 고려한 전송 방법을 제안한다. 제안한 알고리즘을 통해서 전송파워, 물리적 데이터 전송율(변조 수준/방식), 에너지 소모 최소화, 그리고 동시에 할당된 time 구간에서 요구되는 QoS 만족시키는 fragment 크기 등에 대한 최적 조합을 결정할 수 있다. 제안한 알고리즘과 기존의 알고리즘과의 차이점은 전송파워, 데이터 전송율 및 fragment 크기에 대한 모든 파라미터의 조합을 찾는 것이다. 시뮬레이션 결과는 제안한 알고리즘을 통하여 처리량과 에너지 소모 측면에서 성능이 향상되었음을 보인다.

• Korean Chemical Engineering Research
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• 제51권4호
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• pp.460-464
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• 2013

본 연구에서는 $LiMn_2O_4$ 제조에서 Mn 원료로 사용되는 CMD를 seed 첨가법을 사용하여 제조하고자 하였으며, Seed의 열처리 온도가 CMD 합성에 미치는 영향을 고찰하고, 그로부터 제조되는 $LiMn_2O_4$의 전기화학적 특성을 평가하고자 하였다. 제조한 시료의 물성평가는 X-선 회절 분석법(XRD), 주사전자현미경(SEM)을 통하여 실시하였다. 그 결과, $MnCO_3$를 $300^{\circ}C$ 이상의 온도에서 열처리하여 seed로 사용할 경우 ${\gamma}-MnO_2$ 상의 CMD가 얻어졌으며, 그 CMD를 LMO 제조에 사용할 경우 전기화학적 특성이 비교적 우수한 LMO가 얻어졌다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권10호
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• pp.4883-4901
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• 2016

Energy efficiency in Wireless Sensor Networks (WSNs) is very appealing research area due to serious constrains on resources like storage, processing, and communication power of the sensor nodes. Due to limited capabilities of sensing nodes, such networks are composed of a large number of nodes. The higher number of nodes increases the overall performance in data collection from environment and transmission of packets among nodes. In such networks the nodes sense data and ultimately forward the information to a Base Station (BS). The main issues in WSNs revolve around energy consumption and delay in relaying of data. A lot of research work has been published in this area of achieving energy efficiency in the network. Various techniques have been proposed to divide such networks; like grid division of network, group based division, clustering, making logical layers of network, variable size clusters or groups and so on. In this paper a new technique of group based WSNs is proposed by using some features from recent published protocols i.e. "Energy-Efficient Multi-level and Distance Aware Clustering (EEMDC)" and "Energy-Efficient Multi-level and Distance Aware Clustering (EEUC)". The proposed work is not only energy-efficient but also minimizes the delay in relaying of data from the sensor nodes to BS. Simulation results show, that it outperforms LEACH protocol by 38%, EEMDC by 10% and EEUC by 13%.

• 한국물환경학회지
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• 제34권1호
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• pp.121-131
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• 2018

Domestic sewage treatment plants (STPs) consume about 0.5 % of total electric energy produced annually, which is equivalent to 207.7 billion Korean won per year. To minimize the energy consumption and as a way of mitigating the depletion of energy sources, the sewage treatment strategy should be improved to the level of "energy positive". The core processes for the energy positive sewage treatment include A-stage for energy recovery and B-stage for energy-efficient nitrogen removal. The integrated process is known as the A/B-process. In A-stage, chemically enhanced primary treatment (CEPT) or high rate activated sludge (HRAS) processes can be utilized by modifying the primary settling in the first stage of sewage treatment. CEPT utilizes chemical coagulation and flocculation, while HRAS applies returned activated sludge for the efficient recovery of organic contents. The two processes showed organic recovery efficiencies ranging from 60 to 70 %. At a given recovery efficiency of 80 %, 17.3 % of energy potential ($1,398kJ/m^3$) is recovered through the anaerobic digestion and combustion of methane. Besides, anaerobic membrane bioreactor (AnMBR) can recover 85% of organic contents and generate $1,580kJ/m^3$ from the sewage. The recovered energy is equal to the amount of energy consumption by sewage treatment equipped with anaerobic ammonium oxidation (ANAMMOX)-based B-stage, $810{\sim}1,620kJ/m^3$. Therefore, it is possible to upgrade STPs as efficient as energy neutral. However, additional novel technologies, such as, fuel cell and co-digestion, should be applied to achieve "energy positive" sewage treatment.

• 기계저널
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• 제18권3호
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• pp.33-45
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• 1978

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2008년도 추계학술발표대회 논문집
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• pp.251-256
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• 2008

Nowaday, The Sustainable Development about global environment is the most important subject. In urban environment, a variety of the nature energy utilization such as the solar energy are the most efficient solution to solve this issue. One of these efficient solutions, a photovoltaic system using sunlight has been introduced to the building with an advantage such as cost-effective, safe for using and good for environment friendly in light with energy utilization. The BIPV is one of the most interesting and promisingly possibilities of an active use of solar energy at the building. Therefore the goal of this study is to get securing the application information of BIPV as finished envelope. The purpose of this study is to investigate the current performance measurement methods of BIPV module and to measure the performance of BIPV module by mock-up tests.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권7호
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• pp.3080-3099
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• 2016

In this paper, we propose an algorithm for energy efficient cooperative communication in wireless sensor network (WSN). The algorithm computes the appropriate transmission distance corresponding to optimal broadcast bit error probability, while taking the circuit energy consumption and the number of cooperating nodes into consideration. The algorithm guarantees minimum energy consumption by choosing higher value of bit error probability for cooperative phase and lower value of bit error probability for broadcast phase while maintaining the required end-to-end reliability. The simulation results show that the proposed algorithm provides significant energy saving gain when compared with traditional fixed distance schemes and is suitable for applications demanding energy efficiency with high quality of reception.

• 한국지열·수열에너지학회논문집
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• 제17권3호
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• pp.21-29
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• 2021

In this study, the current regulation of the water source energy, one of the renewable energy, was analyzed, and the improvement plan for the high efficient data center cooling system was suggested. In the improvement plan, the design and construction guidelines of the water source energy system permit to adopt the cooling and heating system with or without heat pump. In addition, it should also include the system operated in the cooling mode only all year-round. The domestic test standards to consider the water source operating conditions should be developed. Especially, it is highly recommended that the test standards to include the system with forced cooling and free cooling modes related with the enhanced data center cooling system adopting the water source energy.

• 신재생에너지
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• 제17권1호
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• pp.33-39
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• 2021

The energy use is increasing as the quality of human life improves. and research on the efficient use of energy in ESS (Energy Storage System) is ongoing. An air conditioner is required for the efficient use of an ESS, as are data on the distribution of the temperature of the latter based on the capacity of the air conditioner. In the absence of an air conditioner, the battery of the ESS reaches its maximum temperature of 40℃ after 2 h. When an air conditioner is present, the temperature of the battery stabilizes as the capacity of the former increases.