• Journal of Information Processing Systems
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• v.14 no.4
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• pp.948-960
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• 2018

Many mobile sensing frameworks have been developed to help researcher doing their mobile sensing research. However, energy consumption is still an issue in the mobile sensing research, and the existing frameworks do not provide enough solution for solving the issue. We have surveyed several mobile sensing frameworks and carefully chose one framework to improve. We have designed an adaptive sampling module for a mobile sensing framework to help solve the energy consumption issue. However, in this study, we limit our design to an adaptive sampling module for the location and motion sensors. In our adaptive sampling module, we utilize the significant motion sensor to help the adaptive sampling. We experimented with two sampling strategies that utilized the significant motion sensor to achieve low-power consumption during the continuous sampling. The first strategy is to utilize the sensor naively only while the second one is to add the duty cycle to the naive approach. We show that both strategies achieve low energy consumption, but the one that is combined with the duty cycle achieves better result.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.4_2
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• pp.657-668
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• 2023

It's important to note that air compressors in the industrial sector are major energy consumers, accounting for a significant portion of total energy costs in manufacturing plants, ranging from 12% to 40%. To address this issue, researchers have compared forecasting models that can predict the power consumption of air compressors. The forecasting models were designed to incorporate variables such as flow rate, pressure, temperature, humidity, and dew point, utilizing statistical methods, machine learning, and deep learning techniques. The model performance was compared using measures such as RMSE, MAE and SMAPE. Out of the 21 models tested, the Elastic Net, a statistical method, proved to be the most effective in power comsumption forecasting.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.11 no.3
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• pp.31-39
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• 2012

In this paper, we propose an energy-aware source routing protocol for maximizing a network lifetime in mobile ad hoc network environments. The proposed routing protocol is based on the source routing and chooses a path that maximize the path lifetime, by considering both transmit/receive power consumption and residual battery power in the mobile nodes from the perspective of source-destination end-to-end. This paper proposes a new routing cost and designs a new routing protocol for minimizing the control packet overhead occurred during the route discovery. Simulation results show that the proposed scheme has similar performances to the conventional routing schemes in terms of the number of transmission hops, transmission rate and total energy consumption, but achieves the performance improvement of 20 percent with respect to the lifetime.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1261-1266
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• 2008

Experimental study was performed to understand the operations of a showcase working in a discount store. Temperatures of evaporation, condenser were measured and also electric power consumption of compressor were measured. The purpose of this study is to application use of cold-heat storage systems operated the showcase. At the condition using ice storage system, the ice making process was operated during midnight being not needed the cooling of the showcase through the continuous running of the condenser unit. And then, the refrigerant was sub-cooled using stored cold-heat after being discharged from the air cooling condenser during the day time. The cooling performance was increased owing to the sub-cooling of refrigerant during day time, hence the running time of the compressor was effectively decreased. In other words, this study showed that power consumption during daytime can be transferred to the midnight for making use of the refrigerant sub-cooling. So the operating characteristics of the showcase system under various working conditions were analyzed and discussed.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.4
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• pp.17-23
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• 2012

Ultra low-power design and energy harvesting applications require digital systems to operate under extremely low voltages approaching the point of balance between dynamic and static power consumption which is attained in the sub-threshold operation mode. Delay variations are extremely large in this mode. Therefore, in this paper, a new low-power logic design methodology using asynchronous NCL circuits is proposed to reduce power consumption and not to be affected by various technology variations in nanoscale MOSFET technology. The proposed NCL is evaluated using various benchmark circuits at 0.4V supply voltage, which are designed using 45nm MOSFET predictive technology model. The simulation results are compared to those of conventional synchrouns logic circuits in terms of power consumption and speed.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1293-1295
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• 2001

Recently, according to developing industry and life style, power consumption have been increased year after year. Currently these much power demand from power consumer weakening the allowable power reverse margin in summer. As on of the remedies about this problem, the small scale grid-connected photovoltaic system is considered for auxiliary power source. Generally, grid-connected inverter have a isolation transformer for electrical isolation from utility. This paper proposed transformerless system topology an inquiry validity simulation.

• Journal of Energy Engineering
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• v.27 no.3
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• pp.57-62
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• 2018

The development of coal-fired power plants to ensure energy security and electricity consumption is a matter for the Vietnam economy. However, the huge amount of ash discharged is a major environmental challenge. It is estimated that by the end of 2017, the amount of ash in the country is about 40 million tons and annually emitted over 16.4 million tons. While the quantity of coal-fired power plant is rising, the ash content will increase year by year if the ash doesn't treat well. The ash will be increased from 61 million tons in 2018 to 109 million tons in 2020, 248 million tons in 2025 and 422 million tons in 2030. The difficulties of coal-fired power plants are the problem of ash handling, some plants are at risk of closure because there are not enough dump capacity to storage. Therefore, Vietnam is in need of urgent measures to treat a large amount of waste from coal-fired power plants. The specific objectives of this study were as follows: (1) provide an overview of coal ash situation produced by coal-fired power plants in Vietnam; (2) study about regulations related to coal ash treatment; (3) comprehend the literature review of the cement sector status.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.7-7
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• 2010

Energy harvesting from the environment has been of great interest as a standalone power source of wireless sensor nodes for Ubiquitous Sensor Networks(USN). In particular, the piezoelectric energy harvesting from ambient vibration sources has intensively researched because it has a relatively high power density comparing with other energy scavenging methods. Through recent advances in low power consumption RF transmitters and sensors, it is possible to adopt a micro-power energy harvesting system realized by MEMS technology for the system-on-chip. However, the MEMS energy harvesting system has some drawbacks such as a high natural frequency over 300 Hz and a small power generation due to a small dimension. To overcome these limitations, we devised a novel power generator with a spiral spring structure as shown in the figure. The natural frequency of a cantilever could be decreased to the usable frequency region (under 300 Hz) because the natural frequency depends on the length of a cantilever. In this study, the natural frequency of the energy harvester was a lower than a normal cantilever structure and sufficiently controllable in 50 - 200 Hz frequency region as adjusting weight of a proof mass. Moreover, the MEMS energy harvester had a high energy conversion efficiency using a shear mode ($d_{15}$) is much larger than a 33 mode ($d_{33}$) and the energy conversion efficiency is proportional to the piezoelectric constant (d). We expect the spiral type MEMS power generator would be a good candidate for a standalone power generator for USN.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.12
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• pp.5744-5764
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• 2018

In Wireless Sensor Networks (WSNs) for Internet of Things (IoT) environment, fault tolerance is a most fundamental issue due to strict energy constraint of sensor node. In this paper, a robust energy saving data dissemination protocol for IoT-WSNs is proposed. Minimized energy consumption and dissemination delay time based on signal strength play an important role in our scheme. The representative dissemination protocol SPIN (Sensor Protocols for Information via Negotiation) overcomes overlapped data problem of the classical Flooding scheme. However, SPIN never considers distance between nodes, thus the issue of dissemination energy consumption is becoming more important problem. In order to minimize the energy consumption, the shortest path between sensors should be considered to disseminate the data through the entire IoT-WSNs. SPMS (Shortest Path Mined SPIN) scheme creates routing tables using Bellman Ford method and forwards data through a multi-hop manner to optimize power consumption and delay time. Due to these properties, it is very hard to avoid heavy traffic when routing information is updated. Additionally, a node failure of SPMS would be caused by frequently using some sensors on the shortest path, thus network lifetime might be shortened quickly. In contrast, our scheme is resilient to these failures because it employs energy aware concept. The dissemination delay time of the proposed protocol without a routing table is similar to that of shortest path-based SPMS. In addition, our protocol does not require routing table, which needs a lot of control packets, thus it prevents excessive control message generation. Finally, the proposed scheme outperforms previous schemes in terms of data transmission success ratio, therefore our protocol could be appropriate for IoT-WSNs environment.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.3
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• pp.326-332
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• 2017

A switched VCO-based UWB transmitter for 3-5 GHz is implemented using $0.18{\mu}m$ CMOS technology. Using RF switch and timing control of DPGs, the uniform RF power and low power consumption are possible regardless of carrier frequency. And gate control of RF switch enables the undesired side lobe rejection sufficiently. The measured pulse width is tunable from 0.5 to 2 ns. The measured energy efficiency per pulse is 4.08% and the power consumption is 0.6 mW at 10 Mbps without the buffer amplifier.