• KSII Transactions on Internet and Information Systems (TIIS)
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• 제8권5호
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• pp.1604-1617
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• 2014

This paper proposes RIX-MAC (Receiver-Initiated X-MAC), a new energy-efficient MAC protocol based on an asynchronous duty cycling. RIX-MAC improves energy efficiency through utilizing short preambles and adopting the receiver-initiated approach, where RIX-MAC minimizes sender nodes' energy consumption by enabling transmitters to predict receiver nodes' wake-up times. It also reduces receiver nodes' energy consumption by decreasing the number of control frames. We use the network simulator to evaluate RIX-MAC's performance. Compared to the prior asynchronous duty cycling approaches of X-MAC and PW-MAC, the proposed protocol shows a remarkable improvement in energy-efficiency and end-to-end delay.

• 에너지공학
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• 제23권2호
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• pp.119-124
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• 2014

1970년대 오일쇼크 이후 많은 국가들이 석유에 대한 에너지 의존도를 줄이는 정책을 펼쳤다. 특히, 한국은 빠른 속도의 탈석유화가 일어났으며, 이러한 탈석유화는 급속한 전기화로 이어져 전력수요 급증의 한 요인이 되었다. 본 연구에서는 OECD 34개국을 대상으로 한 1985년부터 2011년까지의 패널자료를 이용하여 탈석유화와 전기화의 관계를 분석함으로써 최근 벌어지고 있는 전력수급난에 대한 정책적 시사점을 제공하고자 한다. 패널분석을 위해 확률효과모형 및 고정효과모형을 적용하였 다. 분석결과 총에너지 소비에서 에너지유 소비 비중(탈석유화 척도)이 10%p 증가하면 전력 소비량이 약 15% 감소하는 것으로 나타났다. 특히 산업용 전력소비가 전체 전력소비에서 차지하는 비중을 국제 비교해보면 우리나라의 경우 OECD 34개 중 4위(2011년 기준)로 나타나는 등 주로 산업부문에서 석유에서 전력으로의 급격한 수요 전환이 현재의 전력수급 위기의 주요 원인 중 하나라는 점을 알 수 있다.

• 한국건설관리학회논문집
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• 제16권3호
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• pp.123-131
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• 2015

온실가스 배출 감소 및 에너지소비량을 감소시키기 위하여 많은 정책들이 수립되고 있다. 그러나 이러한 정책은 건축물의 에너지 소비 특성을 고려하지 않고 건축물에 대하여 일괄적인 에너지 절감률을 적용하고 있다. 일괄적인 에너지소비량 절감율을 일괄적으로 적용할 경우, 에너지소비량이 적은 건축물은 이를 달성 할 수 없다. 따라서 본 연구에서는 건축물의 에너지소비특성에 따른 건축물 분류와 건축물의 에너지소비량에 따른 개별적인 에너지소비량 절감률 산정 방법에 대하여 연구하였다. 에너지소비량 특성 분석결과 건축물의 용도에 따라 에너지소비량 차이가 있음이 나타났다. 또한 이를 바탕으로 건축물을 분류하였다. 또한 기존의 건축물 에너지절감과 관련한 제도들을 분석하여 건축물의 에너지소비량 절감 목표 및 대상 등을 선정하였고. 이을 바탕으로 에너지소비량에 따른 에너지 소비량 절감률 공식을 제안하였다. 또한 서울시 공공건축물 중 제1종 근린생활시설에 본 연구에서 제안한 공식을 적용할 경우 국가 온실가스 배출로드맵에서 목표로 하고 있는 절감률 26%를 달성할 수 있음을 확인하였다. 본 연구를 통하여 건축물의 개별적인 목표 에너지절감률을 산정할 수 있지만, 건축물 목표 에너지 절감률을 실제건축물에 반영하기 위해서는 건축물의 에너지소비량과 에너지소요량의 관계 및 건축물에서 절감 가능한 에너지소비량에 대한 연구가 필요하다.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.185-190
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• 2009

Due to the building energy consumption of total energy consumption of Korea takes over 24%, economizing building energy and using renewable energy resources is being required. To suggest the prototype of zero energy house of country house, the passive systems and active systems are applicated and simulated. In case of wall insulation system is applicated, the heating load of building is reduced. Also, clear triple pair glazing system reduced 2.1% of heating load of building. The amount of reducing heating load by infiltration is depending on the Heating system. In this model, the 0.3ACH made 14.6% saving on heating load from base infiltration 0.82ACH. The solar thermal system of active system could save 80% of DHW and PV system supplies electric power more than average consumption of year. Through the optimum process, the end use of zero energy house of country house is 36kWh/m2.yr and total energy consumption is reduced about 74.2%.

• 의료ㆍ복지 건축 : 한국의료복지건축학회 논문집
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• 제23권1호
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• pp.7-14
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• 2017

Purpose: Since the large hospitals are one of the most intensive energy users among building types in Korea, it is important to investigate and apply appropriate energy conservation measures. There are many researches on energy conservation measures for HVAC system in hospitals, but only few useful guidelines for envelope design variables were existed. The building envelope is one of the important factors to building energy consumption and patients' comfort. The purpose of this study is to suggest the most influential envelope design variables for each end-use energy demand. Methods: 100 samples were generated by LHS(Latin Hypercube Sampling) method. After energy performance simulation, global sensitivity analysis was performed by the regression method. DesignBuilder, Simlab 2.2 and JEPlus were used in this process. Results: The most influencing variables are SHGC, SHGC and VT for heating, cooling, and lighting, respectively. However, the most influencing variable for total energy demand is WWR(Window to Wall Ratio). The analysis was conducted based on the coefficient of variance results. Implications: The six envelop design variables were ranked according to the end-use energy demand.

• 한국정보전자통신기술학회논문지
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• 제14권1호
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• pp.14-21
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• 2021

그린 네트워킹(Green networking)은 유선 데이터 네트워크(Wired data network)에서 통합적인 에너지 관리를 통해 에너지 낭비와 CO2 배출 감소를 유도하기 위해 주요 관심분야가 되었다. 그러나 액세스 네트워크(access networks)는 유선 데이터 네트워크 영역에서 사용자 단말을 제외하면 가장 많은 에너지를 소비하는 영역임에도 불구하고 그 범위가 매우 광대하여 통합적인 관리가 어렵고, 그 에너지 소모량과 에너지 절약 잠재성을 예측하기가 매우 어렵다. 본 논문에서는 기존의 다양한 수학적 예측 모델과 실험 및 실측 데이터를 이용하여 유선 액세스 네트워크의 에너지 소모량 데이터를 수집하고 머신러닝(Machine learning)의 지도학습을 이용한 다중 선형 회귀모델을 생성한다. 또한 생성한 모델로부터 다양한 실험을 통해 회귀모델의 성능을 최적화하여 유선 액세스 네트워크의 에너지 소모량을 예측하였고 생성한 회귀모델은 널리 알려진 평가 지표를 통해 성능을 평가하였다.

• 한국가구학회지
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• 제11권1호
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• pp.61-68
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• 2000

This study was carried out to investigate the effect of grain and veneer thickness on drying rate, required energy consumption, and drying defects such as checking, end waving, and burning during a far-infrared radiation drying process of decorative veneers of hard maple and beech. Most of the veneer could be dried from green to in-use moisture content within 30 to 360 seconds. The drying rates were significantly affected by veneer thickness, but there was little difference between edge-and flat-sliced veneers. The formation of checking during drying test was none or very slight. The percentages of the veneers defected by checks were higher in the flat-sliced veneers than in the edge-sliced veneers. The maximum end wavinesses in the flat-sliced veneers were almost 1.6 to 3 times larger than that in the edge-sliced veneers. All veneers were fee from burned marks during drying test.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2007년도 제32회 펄프종이기술 국제세미나
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• pp.83-125
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• 2007

Increasing energy costs have caused profitability problems for paper suppliers. Therefore unprofitable lines are being closed down. The actions aiming for improved profits are focused either on cost savings or on increasing the capacity of the remaining machines. The runnability of a paper machine and its total efficiency have a significant effect on energy consumption. Producing one ton of waste paper consumes at least as much energy as producing the same amount of sellable end product. New automation solutions enable significant cost-effective improvements to the total efficiency of a line without large investment projects. The measures focus on minimizing changes, interruptions, interruption recovery times and grade change times. Newest actuators, online quality measurements and wet end analysators create an improvement potential, which can be optimally implemented with the latest machine direction control solutions, based on model predictive control concepts. Equally, drying management is significant to the energy consumption. The newest control strategies optimize the use of various drying actuators for different situations; either by responding to changes as efficiently as possible or by using only the cheapest energy sources in stable situations. An even steam supply, which is vital for paper machines, is achieved with control for the power plant steam network. This makes possible to avoid the delays upon starting the paper machine and assure an even steam supply for the drying section and the actuators. This document describes means which have brought significant energy and raw material savings for paper machines. Metso Automation has provided efficiency improvement packages, which are usually based on optimized control of dry weight and drying in all running conditions. The solutions are based on performance analysis, on which the estimations for improvement potential and the necessary actions are based on. Typically benefits on an annual level have been from hundreds of thousands of euros to over one million euro. For example, variations in dry weight have been decreased more than 50%. The results are presented with a few examples. Additionally, the analysis models, adjustment solutions and the changes in running methods with which the results were achieved, are presented.

• Journal of Information Processing Systems
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• 제16권4호
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• pp.845-858
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• 2020

This paper proposes a modified end-to-end secure low energy adaptive clustering hierarchy (ME-LEACH) algorithm for enhancing the lifetime of a wireless sensor network (WSN). Energy limitations are a major constraint in WSNs, hence every activity in a WSN must efficiently utilize energy. Several protocols have been introduced to modulate the way a WSN sends and receives information. The end-to-end secure low energy adaptive clustering hierarchy (E-LEACH) protocol is a hierarchical routing protocol algorithm proposed to solve high-energy dissipation problems. Other methods that explore the presence of the most powerful nodes on each cluster as cluster heads (CHs) are the sparsity-aware energy efficient clustering (SEEC) protocol and an energy efficient clustering-based routing protocol that uses an enhanced cluster formation technique accompanied by the fuzzy logic (EERRCUF) method. However, each CH in the E-LEACH method sends data directly to the base station causing high energy consumption. SEEC uses a lot of energy to identify the most powerful sensor nodes, while EERRCUF spends high amounts of energy to determine the super cluster head (SCH). In the proposed method, a CH will search for the nearest CH and use it as the next hop. The formation of CH chains serves as a path to the base station. Experiments were conducted to determine the performance of the ME-LEACH algorithm. The results show that ME-LEACH has a more stable and higher throughput than SEEC and EERRCUF and has a 35.2% better network lifetime than the E-LEACH algorithm.

• Journal of Advanced Marine Engineering and Technology
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• 제32권7호
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• pp.1044-1050
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• 2008

Most of developed countries, the consumption of fossil fuels has been serious problems that cause serious environment pollution like acid rain, global warming. Also, we have faced that limitation fossil fuels will be exhausted. Currently, small hydropower attracts attention because of its small, clean, renewable, and abundant energy resources to develop. By using a small hydropower generator of which main concept is based on using the different water pressure levels in pipe lines, energy which was initially wasted by use of a reducing valve at the end of the pipeline, is collected by turbine in the hydropower generator. A propeller shaped hydroturbine has been used in order to use this renewable pressure energy. In this study, in order to acquire basic design data of tubular type hydraulic turbine, output power, head, efficiency characteristics due to the flow coefficient are examined in detail. Tubular-turbine among small hydraulic power generation can be used at low-head. The purpose of this study is to research turbine's efficiency due to runner vane angle using CFD analysis.