• The KIPS Transactions:PartC
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• v.14C no.6
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• pp.475-480
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• 2007

Recently, wireless networking devices that depend on the limited Battery and power-saving of wireless hosts became important issue. Batteries can provide a finite amount of energy, therefore, to increase battery lifetime, it is important to design techniques to reduce energy consumption by wireless hosts. This paper improved power saying mechanism in Distributed Coordination Function(DCF) of IEEE 802.11. In the IEEE 802.11 power saving mechanism specified for DCF, time is divided into so-called beacon intervals. At the start of each beacon interval, each node in the power saving mode periodically wakes up during duration called the ATIM Window. The nodes are required to be synchronized to ensure that all nodes wake up at the same time. During the ATIM window, the nodes exchange control packets to determine whether they need to stay awake for the rest of the beacon interval. The size of the ATIM window has considerably affected power-saving. This paper can provide more power-saving than IEEE 802.11 power saving mode because ATIM window size is efficiently increased or decreased.

• Electrical & Electronic Materials
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• v.10 no.10
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• pp.1048-1055
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• 1997

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.42 no.8 s.338
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• pp.35-42
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• 2005

This paper describes novel flip-flops with improved robustness and reduced power consumption. Variable sampling window flip-flop (VSWFF) adjusts the width of the sampling window according to input data, providing robust data latching as well as shorter hold time. The flip-flop also reduces power consumption for higher input switching activities as compared to the conventional low-power flip-flop. Clock swing-reduced variable sampling window flip-flop (CSR-VSWFF) reduces clock power consumption by allowing the use of a small swing clock. Unlike conventional reduced clock swing flip-flops, it requires no additional voltage higher than the supply voltage, eliminating design overhead related to the generation and distribution of this voltage. Simulation results indicate that the proposed flip-flops provide uniform latency for narrower sampling window and improved power-delay product as compared to conventional flip-flops. To evaluate the performance of the proposed flip-flops, test structures were designed and implemented in a $0.3\mu m$ CMOS process technology. Experimental result indicates that VSWFF yields power reduction for the maximum input switching activity, and a synchronous counter designed with CSR-VSWFF improves performance in terms of power consumption with no use of extra voltage higher than the supply voltage.

• Journal of Power System Engineering
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• v.20 no.1
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• pp.57-62
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• 2016

In this study, design the core part of the driving of the robot. The power of the driving is window motor for automobiles obtained by using a method of directly to the motor shaft of the worm gear type. The decelerator consists of a worm gear to receive power from the motor shaft, Helical gear contact to worm gear, a pinion gear to be connected in line with the helical gear, and an output shaft to be engaged to the pinion gear. Drive system by using the power from the motor shaft based on the deceleration gear designed by the gear ratio set by the gear teeth increases the torque.

• Proceedings of the KIEE Conference
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• 2001.11c
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• pp.323-326
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• 2001

In this Paper, we are trying to think over the operation window of application to a domestic burner management system and the softwares. The detailed contents are the power plant system overview and the integration of operation window and the software[man-machine interface software and logic editing software] digest and the difficulty in changing the burner management system.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.51-53
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• 2001

Permanent Magnet DC Motors are widely used in Automotive parts because they have cheap price, simple structure and high torque-speed ratio. But the motor in automotive parts is required high quality, complex function and lower price than before. This paper deals with design of controller for safety function that body trap on the automotive window. The algorithm of controller can adapt variety conditions with temperature, electrical, driving, etc.

• Journal of Power Electronics
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• v.10 no.4
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• pp.412-418
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• 2010

This paper proposes a new algorithm to generate a reference signal for an active power filter using a sliding-window FFT operation to improve the steady-state performance of the active power filter. In the proposed algorithm the sliding-window FFT operation is applied to the load current to generate the reference value for the compensating current. The magnitude and phase-angle for each order of harmonics are respectively averaged for 14 periods. Furthermore, the phase-angle delay for each order of harmonics passing through the controller is corrected in advance to improve the compensation performance. The steady-state and transient performance of the proposed algorithm was verified through computer simulations and experimental work with a hardware prototype. A single-phase active power filter with the proposed algorithm can offer a reduction in THD from 75% to 4% when it is applied to a non-linear load composed of a diode bridge and a RC circuit. The active power filter with the proposed reference generation method shows accurate harmonic compensation performance compared with previously developed methods, in which the THD of source current is higher than 5%.

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.61-62
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• 2006

In this paper, using Bianchi's model with channel idle probability we analyze performance of power management scheme of IEEE 802.11 DCF according to ATIM window size and number of nodes for wireless ad hoc networks. The analytical results show that, when the number of nodes is given, the selected ATIM window size limits the performance.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.475-477
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• 2010

In the power saving mechanism specified in IEEE 802.11, all node use the sam ATIM window size. Since the ATIM window size critically affects throughput and energy consumption, a fixed ATIM window does not perform well in all situations. This paper proposes the efficient power management mechanism considering network characteristic in 802.11. To reflect the network characteristic, the paper uses th (m,k)-firm deadline technique. Simulation result shows that proposed mechanism outperforms the IEEE 802.11 power saving mechanism in terms of the amount of power consumed.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.670-672
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• 2014

In this study, we investigate active control of noise transmitted through a window of enclosures minimizing the acoustic power. To reduce noise of the enclosures, passive methods with absorbing material are generally used. The passive methods, however, are limited use due to the vantilation windows. In this case, these windows are path of noise leakage. Feedforward active noise control technology is applied to minimize the sound power from the enclosure. The feedforward controller is implemented with FIR filter based on the transfer functions calculated numerically. The controller reflects the delay due to FIR filter. The noise transmitted through the window is actively controlled, and the reduction of the power is obtained by 15dB.