• Journal of the Korea Society of Computer and Information
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• v.17 no.12
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• pp.137-148
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• 2012

In this paper, we proposed the location-aware coordinate routing algorithm for improving the performance of routing algorithm by using ZigBee in Smart Grid environment. A distributed address allocation scheme used an existing algorithm that has wasted in address space. The x, y and z coordinate axes from divided address space of 16 bit to solve this problems. However, coordinate routing does not take account of wireless link condition. If wiress link condition is not considered, when the routing table is updated, the nodes with bad link conditions are updated in the routing table and can be chosen as the next hop. This brings out the retransmissions because of received packet's errors. Also, because of these retransmissions, additional power is consumed. In this paper, we propose the location-aware coordinate routing algorithm considering wiress link condition, where reliable data transmission is made and the consumed enegy is minimize. and we compared and connected region and transition region of ZigBee location based routing in the aspect of average number of multi hops, subordinate packet delivery ratio, delay time, and energy consumption of proposed algorithm. It turned out that there were improvements in performances of each items.

• 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 Ship and Ocean Technology
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• v.3 no.4
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• pp.15-22
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• 1999

It is known that lubrication effect of an air cavity can reduced a drag of a ship. The present study intends to utilize the phenomena for the drag reduction of a passenger ship now operating in a lake. A scaled model of the model when air cavities are formed under the bottom of the model. Model experiments have been performed to determine adequate air supply rates, proper shapes and locations of air supply nozzles. It is shown that energy saving of mere than 10% can be achieved at the design speed of the ship even after excluding additional power consumed for air supplying. Multiple air supply nozzles, if allocated properly, are more effective than single one in resistance reduction of the ship.

• Tribology and Lubricants
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• v.29 no.5
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• pp.310-317
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• 2013

To reduce vehicle fuel consumption due to not only driving but also air conditioning, battery-operated non-starting conditioning systems with thermoelectric modules and without mechanical elements like compressors are being manufactured for use by hybrid heavy trucks in the near future. In this study, the voltage and current consumed by a thermoelectric module were measured to determine the required battery power, and the performance of the conditioning system with air temperature, and humidity of the inlet/outlet modules and inside/outside the cabin for a truck, was evaluated using experimental apparatus under actual conditions. The results showed that, the thermoelectric module can be continously operated for about 1.5 h using existing 24 V batteries. The coefficent of performance(COP) of the cooling and heating modes was calculated to be an average 0.8-1.32. As expected, the heating performance was 30% more efficient than the cooling performance, which is general characteristic of thermoelectric modules.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.1
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• pp.51-58
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• 2015

This paper proposes a 10-b SAR ADC. To increase the conversion speed and reduce the power consumption and area, redundant cycles were implemented digitally in a capacitor DAC. The capacitor DAC algorithm was straightforward switching, which included digital error correction steps. A prototype ADC was implemented in CMOS $0.18-{\mu}m$ technology. This structure consumed $140{\mu}W$ and achieved 59.4-dB SNDR at 1.25MS/s under a 1.8-V supply. The figure of merit (FOM) was 140fJ/conversion-step.

• Journal of Magnetics
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• v.21 no.3
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• pp.405-412
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• 2016

In general, surface mounted PM synchronous motors (SPMSMs) are mainly adopted as a driving motor for high-speed applications, because they have high efficiency and high power density. However, the SPMSMs have some weak points such as the increase of magnetic reluctance and additional losses as a consequence of using a non-magnetic sleeve. Especially, the magneto-motive force (MMF) in the air-gap of the SPMSMs is weakened due to the magnetically increased resistance. For that reason, a large amount of PM is consumed to meet the required MMF. Nevertheless, it cannot help using the sleeve in order to maintain the mechanical integrity of a rotor assembly in high-speed rotation. Thus, in this paper, a multi-layer interior PM synchronous motor (IPMSM) not using the sleeve is presented and designed as an alternative of a SPMSM. Both motors are evaluated by test results based on a variety of characteristics required for an air blower system of a fuel cell electric vehicle.

• Proceedings of the KIEE Conference
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• 1991.11a
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• pp.423-426
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• 1991

A Plasma Display Panel with Double Pulse Memory was fabricated and its luminance and luminous efficacy were investigated. Application of non-discharge pulses to an auxiliary anode increased luminance by 43% and luminous efficacy by 33%. Compared to PDP with PPM(Planar Pulse Memory) driving technique, PDP with DPM obtained higher luminous efficacy and consumed lower power with the same delay time.

• Journal of electromagnetic engineering and science
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• v.4 no.3
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• pp.107-112
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• 2004

In this paper, the phase noise of 900 MHz VCO is improved using modified strip line square ring resonator. In order to demonstrate the phase noise improvement of the proposed VCO, the same circuit was manufactured using shorted-circuit resonator. In condition of the same bias current, the phase noise of the proposed VCO with modified square ring resonator is suppressed by 7 dB as - 103 dBc/Hz at 100 kHz offset compared to the conventional VCO with short-circuit resonator. From the proposed VCO, we achieved output power of - 4.8 dBm, harmonics suppression of 16 dB, and tuning bandwidth of 100 MHz. The proposed VCO consumed 5 mA at 3 V, and its size is 1.2 cm ${\times}$ 1.0 cm.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.5
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• pp.63-69
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• 1999

In tis study the effects of the maximum grit depth of cut on the grinding characteristics were investigated. They are AE signals produced during grinding processes have been studied to find out the appropriate AE parameters for assessing grinding processes. SM45C steel has been ground under the conditions yielding removal rate of workpiece 100, 200,300, and 400m{{{{ {m }^{3 } }}}}/min which was achieved by altering workpiece velocity(v) and apparent depth of cut(Z). According to the experimental result the value of surface roughness increases but grinding power energy rate of AE signal(AErmas2) and specific grinding energy consumed decrease as increasing the maximum grit depth of cut.

• Journal of Microbiology and Biotechnology
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• v.11 no.3
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• pp.406-411
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• 2001

In a bacterial denitrification test with Pseudomonas sp. and anaerobic consortium, more nitrates and less substrate were consumed but less metabolic nitrite was produced under an anaerobic $H_2$ condition rather than under $N_2$ condition. In a bioelectrochemical denitrification test with the same organisms, the electrochemically reduced neutral red was confirmed to be a substitute electron donor and a reducing power like $H_2$. The biocatalytic activity of membrane-free bacterial extract, membrane fraction, and intact cell for bioelectrochemical denitrification was measured using cyclic voltammetry. When neutral red was used as an electron mediator, the electron transfer from electrode to electron acceptor (nitrate) via neutral red was not observed in the cyclic voltammogram with the membrane-free bacterial extract, but it was confirmed to gradually increase in proportion to the concentration of nitrate in that of the membrane fraction and the intact cell of Pseudomonas sp.