• 한국유기농업학회지
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• 제9권4호
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• pp.53-69
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• 2001

The word \"permaculture\" is a contraction of \"permanent agriculture\" or \"permanent culture\". Permaculture principles are designed to support (or ensure) the survival of humanity, the earth and all on it, and, to improve our standard of living, Permaculture can be defined as : a design system for creating sustainable human environments that can be (relatively) easily constructed and maintained. The principles of permaculture designs are relative location every element (such as house , rice paddy, road, esc) is placed in relation to each other such that each assists the other : each element performs multiple functions ; each function is supported by many elements : energy efficient planning ; using biological resources rather than fossil fuels : energy cycling on site (both fuel and human energy) : Using and accelerating natural plant succession to establish favourable sites and soils ; poly-culture and diversity of beneficial species for a productive, interactive system ; use of edge and natural patterns for best effect. These principles can be used for any permaculture design, in any climate, and at any scale. There has been very little scientific examination of Permaculture, and as such, it must be viewed as a design philosophy.viewed as a design philosophy.

• 전기학회논문지
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• 제63권6호
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• pp.820-827
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• 2014

Since a microgrid has renewable energy sources, imbalance between power supply and power demand occurs in the islanded mode. In order to solve the imbalance, several energy storage systems (ESSs) such as bettary energy storage system (BESS), EDLC (electric double layer capacitor), flywheel, and SMES (superconducting magnetic energy storage) are generally used. Especially, their electrical characteristics are different. For efficient use of them, a coordinated control scheme is required. In this paper, a coordinated control scheme for using a Lead-acid BESS, a Lithium BESS, and a EDLC is designed to efficient frequency control for a microgrid in the islanded mode. The coordinated frequency control strategy is designed based on their electrical characteristics. The feasibility of the proposed coordinated frequency control strategy is verified through the simulation.

• International Journal of Internet, Broadcasting and Communication
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• 제14권1호
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• pp.188-193
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• 2022

The energy efficiency of memory systems is an important task in designing future computer systems as memory capacity continues to increase to accommodate the growing big data. In this article, we present an energy-efficient last-level cache management policy for future mobile systems. The proposed policy makes use of low-power PCM (phase-change memory) as the main memory medium, and reduces the amount of data written to PCM, thereby saving memory energy consumptions. To do so, the policy keeps track of the modified cache lines within each cache block, and replaces the last-level cache block that incurs the smallest PCM writing upon cache replacement requests. Also, the policy considers the access bit of cache blocks along with the cache line modifications in order not to degrade the cache hit ratio. Simulation experiments using SPEC benchmarks show that the proposed policy reduces the power consumption of PCM memory by 22.7% on average without degrading performances.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2013년도 춘계학술대회
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• pp.531-533
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• 2013

본 논문에서 연구하고자 하는 IPMC(Ionic exchange Polymer Metal Composite)는 술폰산 이온기와 플루오르화 탄소의 결합으로 이루어진 Nafion 필름을 사용한 소재로 전기 활성 고분자(Electro Active Polymer) 특성과 물의 유무 및 양이온에 크게 영향을 받는 특성을 지닌다. 즉, 전기 에너지를 기계적 에너지로 활용 하거나, 기계 에너지를 전기 에너지로 활용 할 수 있으며, 물과 물속의 양이온에 따라 그 특성도 크게 달라진다. 이러한 IPMC의 전기적 특성을 연구하기 위하여 모의실험 장치를 구성하였다. 이 모의 실험 장치에는 MCU 와 Stepper Motor를 사용 하여 해류의 기계적 움직임을 구현 하도록 하여 움직임에 따른 전기적 특성 분석을 하도록 설계 하였다. 본 연구에서는 IPMC와 모의실험 장치를 구성 하여 해류 에너지의 효율 적인 사용을 위하여 IPMC의 면적, 주파수, 염분의 농도, Bending 각도에 따른 전기적 분석 연구 방법을 통해 IPMC의 효율적인 사용 방법을 제안하고자 한다.

• Nuclear Engineering and Technology
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• 제51권5호
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• pp.1181-1194
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• 2019

A new moving-mesh Finite Volume Method (FVM) for the efficient solution of the two-dimensional neutron diffusion equation is introduced. Many other moving-mesh methods developed to solve the neutron diffusion problems use a relatively large number of sophisticated mathematical equations, and so suffer from a significant complexity of mathematical calculations. In this study, the proposed method is formulated based on simple mathematical algebraic equations that enable an efficient mesh movement and CV deformation for using in practical nuclear reactor applications. Accordingly, a computational framework relying on a new moving-mesh FVM is introduced to efficiently distribute the meshes and deform the CVs in regions with high gradient variations of reactor power. These regions of interest are very important in the neutronic assessment of the nuclear reactors and accordingly, a higher accuracy of the power densities is required to be obtained. The accuracy, execution time and finally visual comparison of the proposed method comprehensively investigated and discussed for three different benchmark problems. The results all indicated a higher accuracy of the proposed method in comparison with the conventional fixed-mesh FVM.

• 토지주택연구
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• 제3권3호
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• pp.249-261
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• 2012

건물운용단계의 에너지사용량은 우리나라 전체에너지 사용량의 약 25%이다. 지금까지 건물의 에너지사용량을 줄이기 위해서는 주로 설계단계에서 단열을 강화하고 고효율 기기를 사용해왔다. 이러한 노력들은 에너지절약 측면에서 그 한계가 있으며, 사용단계에서의 에너지절약생활이 큰 비중을 차지함에 따라 입주자들의 자발적인 참여로 인한 에너지절약 방법이 보다 효과적이라 할 수 있다. 이를 위해 본 연구에서는 에너지사용자에게 보다 적극적으로 에너지절약 프로그램에 동참시키기 위해 본인들이 사용한 에너지실적 정보를 웹상에서 서로 공유할 수 있는 프로그램을 개발하였다. 또한 프로그램의 필요성 및 사용의지를 조사하고 시범 적용하여 유효데이터의 수집가능성과 프로그램의 사용 용이성에 대하여 평가하였다.

• 스마트미디어저널
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• 제5권4호
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• pp.41-48
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• 2016

In mobile ad hoc networks(MANETs), all the nodes in a network have limited resources. Therefore, communication topology which has long lifetime is suitable for nodes in MANETs. And MANETs are exposed to various threats because of a new node which can join the network at any time. There are various researches on security problems in MANETs and many researches have tried to make efficient schemes for reducing network power consumption. Power consumption is necessary to secure networks, however too much power consumption can be critical to network lifetime. This paper focuses on energy efficient monitoring node distribution for enhancing network lifetime in MANETs. Since MANETs cannot use centralized infrastructure such as security systems of wired networks, we propose an efficient IDS node distribution scheme using minimum spanning tree (MST) method to cover all the nodes in a network and enhance the network lifetime. Simulation results show that the proposed algorithm has better performance in comparison with the existing algorithms.

• 한국의류산업학회지
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• 제10권6호
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• pp.1058-1063
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• 2008

The use of clothes dryers is increasing in Korea and throughout Asia, because of preference for the drum type washer dryer. Clothes dryers consume more energy than almost any other home appliance. This paper suggests efficient ways for drying laundry with condensing clothes drier. We dried cotton fabrics with the condensing clothes dryers and observed the energy input, temperature and RH of the dryer during the drying process. In the early stages of drying process, the air temperature inside the clothes dryer decreased and the RH and the drying time increased as the weight of fabrics increased. We found that it was important to consider the total weight of the fabrics that included heat-sensitive fibers. It took more than half the drying time and the energy input for a 2.5 kg load that it did for a 5 kg load. Therefore, drying larger one load was more efficient than divided smaller loads, because increasing the weight of the fabrics reduced the energy input per kg of drying clothes. The lower the initial moisture regains of the fabrics were, the lower the energy input and the drying time were. The energy input for spinning after washing was much less than that for drying in the dryer. Consequently, it is more efficient to reduce the moisture content of the clothes by lengthening the spinning time of the washer to reduce the energy consumption and the drying time. During the drying process opening the door twice for 30 seconds each time lowered the air temperature and the RH of the dryer, but did not affect the moisture regain of the fabrics, the drying time, and the energy input.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.959-964
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• 2006

Recently, an international oil price shows fluctuation in 70 dollars per barrel and it is said that this trend is able to continues for much longer. Because energy consumption in buildings accounted for about 25% of the nation's total demand for energy, Energy censervation and efficiency of buildings were very important issues. Main political measures relating to building energy use and saving were 'the system of accrediting green building', 'building energy certification system', 'energy consumption efficiency rating indication system', 'building energy code', 'high efficient energy materials certification system'. This paper presents approaches to improve building energy efficiency policy.

• 한국지능시스템학회논문지
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• 제20권1호
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• pp.36-41
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• 2010

무선 센서 네트워크의 효율적인 에너지 사용과 개별 노드의 수명 증대는 센서 네트워크의 효율적인 운영을 위한 매우 중요한 요소이다. 센서 네트워크에 많이 사용되는 LEACH, HEED 등과 같은 클러스터 기반의 라우팅 방식들은 클러스터 헤드들과 해당 멤버 노드들 간의 데이터 전달을 통하여 에너지의 효율성을 얻는다. 본 논문에서는 대표적인 클러스터 기반 라우팅 방식인 LEACH와 HEED의 방법을 비교분석하고 데드 노드의 최대 지연 발생 등과 같은 새로운 에너지 효율적인 클러스터 헤드 선출 방법을 제안한다. 제안된 방법의 효율성은 MATLAB 시뮬레이션을 통해 확인하였다.