• The Journal of the Convergence on Culture Technology
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• v.10 no.3
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• pp.879-884
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• 2024

Wireless sensor network technology is becoming increasingly important with the advancement of the Fourth Industrial Revolution. Consequently, various protocols such as LEACH, PEGASIS, and EEACP have been developed in an attempt to increase energy efficiency. However, the EEACP protocol still has room for improvement in terms of energy consumption during transmission. Particularly, inefficient paths associated with data reception settings may compromise the network's survivability. The proposed A-EEACP protocol optimizes data transmission direction around the sink node to reduce energy consumption and enhance the network's survivability.

• Asian-Australasian Journal of Animal Sciences
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• v.4 no.4
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• pp.361-368
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• 1991

In two experiments 640 starcross replacement pullets between 25 and 154 days of age were fed ad libitum on either of 16 diets formed by the combination of $4CP{\times}4ME$ levels to study the interaction of CP and ME on growth performances. In both experiments, feed intake decreased, but protein intake, energy intake, live weight gain and feed conversion efficiency increased and sexual maturity hastened with the increase of dietary protein and/or energy level. The protein conversion efficiency decreased with the increase of dietary protein level. The energy conversion efficiency, however, did not show any relationship with dietary energy level. There was a greater improvement of growth performance due to simultaneous increase of dietary protein and energy level than that of increasing protein or energy alone.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.5
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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.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.11a
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• pp.37-42
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• 2004

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2004.11a
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• pp.183-188
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• 2004

• Journal of Urban Science
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• v.11 no.1
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• pp.15-20
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• 2022

The issue of hotel energy use is growing more significant as the hotel industry expands. It is important to take into account the electrical installation and space-specific features in a room unit in order to comprehend the energy consumption of a hotel guestroom. In light of this, this study aimed to analyze standby power for enhancing the energy efficiency of a hotel guestroom during check-out status. This study was conducted in three steps: (i) data collection; (ii) analysis of energy consumption patterns; and (iii) analysis of energy efficiency improvement plan. The main findings of this study can be summarized as follows. First, 32.24% of energy was used in fan coil unit) during check-out status. Second, a hotel guestroom had a 4.30% energy saving potential, based on energy consumption patterns during check-out status. This study can contribute to support hotel management to operate guestrooms differently by helping them identify patterns in energy use and realize potential savings.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.3
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• pp.246-251
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• 2013

Screen printing is commonly used to form the front/back electrodes in silicon solar cell. But it has caused high resistance and low aspect ratio, resulting in decreased conversion efficiency in solar cell. Recently the plating method has been combined with screen-printed c-Si solar cell to reduce the resistance and improve the aspect ratio. In this paper, we investigated the effect of light induced silver plating with screen-printed c-Si solar cells and compared their electrical properties. All wafers were textured, doped, and coated with anti-reflection layer. The metallization process was carried out with screen-printing, followed by co-fired. Then we performed light induced Ag plating by changing the plating time in the range of 20 sec~5min with/without external light. For comparison, we measured the light I-V characteristics and electrode width by optical microscope. During plating, silver ions fill the porous structure established in rapid silver particle sintering during co-firing step, which results in resistance decrease and efficiency improvement. The plating rate was increased in presence of light lamp, resulting in widening the electrode with and reducing the short-circuit current by shadowing loss. With the optimized plating condition, the conversion efficiency of solar cells was increased by 0.4% due to decreased series resistance. Finally we obtained the short-circuit current of 8.66 A, open-circuit voltage of 0.632 V, fill factor of 78.2%, and efficiency of 17.8% on a silicon solar cell.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2007.05a
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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.

• Vacuum Magazine
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• v.1 no.4
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• pp.4-9
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• 2014

About 170 years has been passed since the concept of photovoltaic has been suggested by French physicist Alexandre-Edmond Becquerel. Now the highest efficiency of solar cell has reached up to 44% by III-V multi-junction solar cells with concentrator. Those multi-junction solar cells are suitable as energy source for spaceships. On the other hand, the cell efficiency of solar cell for electric power generation as energy source for Earth has is going to be saturated although commercial solar cell efficiency is around 20%. In the part 1 of this article, the history of III-V multi-junction solar cells which have been adapted for spaceships is explained and in the part 2, new approach for the improvement of cell efficiency is suggested as the energy source for Earth.

• Journal of Environmental Science International
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• v.27 no.2
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• pp.99-107
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• 2018

In order to design the improvement process for T-N removal, the treatment process of Suyoung, Gangbyeon, and Noxan sewage treatment plants (STP) in Busan was anlayzed. Suyoung STP shows a T-N removal efficiency of about 69.8% with MLE(Modified Ludzack ettinger) and A2O+MBR. However, it is necessary to improve the process to maintain over DO of 1 mg/L and is required to install a flow control tank to minimize the rainfall effect. Gangbyun STP shows a about 70.2% T-N removal efficiency with A2O+GFF(gravity fiber filtration). However, in order to improve T-N removal efficiency, it is needed to install MLE process to treat recycle water. Noksan STP shows a T-N removal efficiency of about 71.0% with MLE+Chemical treatment and shows stable T-N concentration in effluent. However, it is required a toxic chemical management process because bad wastewater flows into the STP, also is necessary a process improvement in order to increase internal recycling ratio. Especially, it is required a process improvement to increase HRT of nitrification tank because Suyoung and Gangbyeon STPs shows low nitrification efficiency during winter season.