• Proceedings of the Korean Society for Agricultural Machinery Conference
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• v.10 no.2
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• pp.273-279
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• 2005

• Journal of Electrochemical Science and Technology
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• v.13 no.1
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• pp.78-89
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• 2022

ANODE-free Li-metal batteries (AFLMBs) operating with Li of cathode material have attracted enormous attention due to their exceptional energy density originating from anode-free structure in the confined cell volume. However, uncontrolled dendritic growth of lithium on a copper current collector can limit its practical application as it causes fatal issues for stable cycling such as dead Li formation, unstable solid electrolyte interphase, electrolyte exhaustion, and internal short-circuit. To overcome this limitation, here, we report a novel dual-salt electrolyte comprising of 0.2 M LiPF₆ + 3.8 M lithium bis(fluorosulfonyl)imide in a carbonate/ester co-solvent with 5 wt% fluoroethylene carbonate, 2 wt% vinylene carbonate, and 0.2 wt% LiNO₃ additives. Because the dual-salt electrolyte facilitates uniform/dense Li deposition on the current collector and can form robust/ionic conductive LiF-based SEI layer on the deposited Li, a Li/Li symmetrical cell exhibits improved cycling performance and low polarization for over 200 h operation. Furthermore, the anode-free LiFePO₄/Cu cells in the carbonate electrolyte shows significantly enhanced cycling stability compared to the counterparts consisting of different salt ratios. This study shows an importance of electrolyte design guiding uniform Li deposition and forming stable SEI layer for AFLMBs.

• The KIPS Transactions:PartC
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• v.16C no.4
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• pp.535-542
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• 2009

Wireless Sensor Network (WSN) is a wireless network consisting of spatially distributed autonomous devices, using sensors to cooperatively monitor physical or environmental conditions. WSNs face the critical challenge of sustaining long-term operation on limited battery energy. Coverage maintenance has been proposed as a promising approach to prolong network lifetime. Mobile sensors equipped with communication devices can be leveraged to overcome the coverage problem. In this paper, we propose a stepwise movement scheme using perimeter coverage property for the coverage maintenance problem. In our scheme, each sensor monitors neighboring dead nodes, determines vulnerable node (i.e. dead node which makes uncovered area), computes the center of uncovered area HC, and makes a coordinated stepwise movement to compensate the uncovered area. In our experimental results, our scheme shows at least 50 % decrease in the total moving distance which determines the energy efficiency of mobile sensor.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.11
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• pp.1584-1589
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• 2012

The grid-interconnected microgrid can be able to operate with and without the utility microgrid to supply electricity. when the microgrid operates in grid-connected mode, the frequency of the microgrid synchronizes with the system frequency. In this case, the frequency of the microgrid has small variation which is able to change the output of distributed generation with a droop controller. Thus, the small variation of frequency can make the distributed generation generate unnecessary electricity consistently. In this paper, we propose a frequency droop control with a dead band so as to prevent the distributed generations from generating unnecessary output while in grid-interconnected mode. In addition, a distributed generation can have a restoration control to restore the frequency changed by a droop control as a rated frequency. Also, we state the problem of restoration control with a dead band, and propose its solution when the microgrid operates in stand alone mode. We simulate the proposed droop control using PSCAD/EMTDC to verify the validity of the control.

• Journal of Animal Environmental Science
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• v.11 no.1
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• pp.35-44
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• 2005

The objectives of this study were to develop an image processing algorithm for finding the sick or the dead layers(SDL) rearing in the multi-tier layer battery, which is a core technology of remote monitoring systems for layers, and to test the performance of algorithm developed in the experimental poultry housing. Based on the literature study and experiment, the standing up of layer was set as a criterion for judging layers whether sick or dead. Then, by the criterion set, an algorithm was developed. The image processing algorithm developed was tested how well it could and SDL at the experimental poultry housing. Test results showed that its monitoring correctness of layers standing up in the cages having all healthy layers was $92\%$, and $96\%$ in the cages having SDL. Therefore, it would be concluded that the image processing algorithm developed in this study was well suited to the purpose of development.

• International Journal of Computer Science & Network Security
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• v.23 no.10
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• pp.169-178
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• 2023

Wireless sensor network is wieldy use for IoT application. The sensor node consider as physical device in IoT architecture. This all sensor node are operated with battery so the power consumption is very high during the data communication and low during the sensing the environment. Without proper planning of data communication the network might be dead very early so primary objective of the cluster based routing protocol is to enhance the battery life and run the application for longer time. In this paper we have comprehensive of twenty research paper related with clustering based routing protocol. We have taken basic information, network simulation parameters and performance parameters for the comparison. In particular, we have taken clustering manner, node deployment, scalability, data aggregation, power consumption and implementation cost many more points for the comparison of all 20 protocol. Along with basic information we also consider the network simulation parameters like number of nodes, simulation time, simulator name, initial energy and communication range as well energy consumption, throughput, network lifetime, packet delivery ration, jitter and fault tolerance parameters about the performance parameters. Finally we have summarize the technical aspect and few common parameter must be fulfill or consider for the design energy efficient cluster based routing protocol.

• Journal of KIISE:Information Networking
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• v.33 no.5
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• pp.395-406
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• 2006

In ad hoc networks, the limited battery capacity of nodes affects a lifetime of network Recently, a large variety of power-aware routing protocols have been proposed to improve an energy efficiency of ad hoc networks. Existing power-aware routing protocols basically consider the residual battery capacity and transmission power of nodes in route discovery process. This paper proposes a new power-aware routing protocol, TDPR(Traffic load & lifetime Deviation based Power-aware Routing protocol), that does not only consider residual battery capacity and transmission power, but also the traffic load of nodes and deviation among the lifetimes of nodes. It helps to extend the entire lifetime of network and to achieve load balancing. Simulations using ns-2[14] show the performance of the proposed routing protocol in terms of the load balancing of the entire network, the consumed energy capacity of nodes, and an path's reliability TDPR has maximum 72% dead nodes less than AODV[4], and maximum 58% dead nodes less than PSR[9]. And TDPR consumes residual energy capacity maximum 29% less than AODV, maximum 15% less than PSR. Error messages are sent maximum 38% less than PSR, and maximum 41% less than AODV.

• Journal of Biosystems Engineering
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• v.31 no.5 s.118
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• pp.436-442
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• 2006

This research was conducted to design and develop a wired monitoring system for judging if sick or dead layers (SDL) exist in multi-tier layers battery (MLB) by machine vision, and to analyze its performance. In this study, 20 Brown Leghorn (Hi-Brown) layers aged 37 weeks old, were used as the experimental animals. The intensity of concern paid by layers on feed was over 90% during 5 minutes and 30 seconds after providing feed, and normal layers (NL) had been standing to take feed for that period. Therefore, in this study, the optimal judging time was set by this test result. The wired monitoring system developed was consisted of a driving device for carrying machine vision systems, a control program, a RS232 to RS485 convertor, an automatic positioning system, and an image capture system. An image processing algorithm was developed to find SDL in MLB by the processes of binary processing, erosion, expansion, labeling, and reckoning central coordinate of the captured images. The optimal velocity for driving unit was set up as 0.13 m/s by the test results for wired monitoring system, and the proximity switch was controlled not to be operated for 1.0 second after first image captured. The wired monitoring system developed was tested to evaluate the remote monitoring performance at lab-scale laying hen house. Results showed that its judgement success.ate on normal cage (without SDL) was 87% and that on abnormal cage (with SDL) was 90%, respectively. Therefore, it would be concluded that the wired monitoring system developed in this study was well suited to the purpose of this study.

• Journal of KIISE:Information Networking
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• v.35 no.2
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• pp.158-165
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• 2008

In this paper, we present a MMPR (Minimizing the Maximum Used Power Routing) Algorithm in a MANET (Mobile ad hoc network) by modifying the route selection algorithm in well-known routing MANET protocol. In the previous route selection algorithms, the metric for cost function is the minimal hop which does not consider the energy status. MMPR uses the metric with used energy The node that want to know the route for some destination begins calculating the route cost function with alpha which is the maximum used energy in the known route. If the new route that contains the node whose used energy is greater than previous known alpha is known to the node that want to send a packet in some moment, the probability of selecting the new route is lower. Experimental results with MMPR show higher performance in both the maximum used energy and the number of dead nodes than that of the CMMBCR (Conditional Max-Min Battery Routing).

• Journal of Power Electronics
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• v.16 no.6
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• pp.2035-2044
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• 2016

In order to match the voltages between high voltage battery stacks and low voltage super-capacitors with a high conversion efficiency in hybrid energy sources electric vehicles (HESEVs), a high ratio bidirectional DC-DC converter with a synchronous rectification H-Bridge is proposed in this paper. The principles of high ratio step-down and step-up operations are analyzed. In terms of the bidirectional characteristic of the H-Bridge, the bidirectional synchronous rectification (SR) operation is presented without any extra hardware. Then the SR power switches can achieve zero voltage switching (ZVS) turn-on and turn-off during dead time, and the power conversion efficiency is improved compared to that of the diode rectification (DR) operation, as well as the utilization of power switches. Experimental results show that the proposed converter can operate bidirectionally in the wide ratio range of 3~10, when the low voltage continuously varies between 15V and 50V. The maximum efficiencies are 94.1% in the Buck mode, and 93.6% in the Boost mode. In addition, the corresponding largest efficiency variations between SR and DR operations are 4.8% and 3.4%. This converter is suitable for use as a power interface between the battery stacks and super-capacitors in HESEVs.