• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.193-199
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• 2011

In this paper, we proposed battery driven low power algorithm in mobile device. Algorithm the mobile devices in power of the battery for the task to perform power consumption to reduce the frequency alters. Power of the battery perform to a task power consumption of is less than the task perform to frequency the lower. Frequency control the task, depending on in the entire system devices used among the highest frequency with devices first target perform to. Frequency in the decrease the second largest frequency with of the device the frequency in changes the power consumption to calculate. The calculated consumption power the battery of level is greater than level the frequency by adjusting power consumption, lower power of the battery the task perform when you can to the frequency to adjust. Experiment the frequency by adjusting power consumption a method to reduce using [6] and in the same environment power of the battery consider the task to perform frequency were controlled. The results in [6] perform does not battery power on task operates that the result was.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.253-255
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• 2003

Electricity is the prime commodity in mobile device, e.g. smart phone, PDA, MP3 player and etc. This strict restriction on power consumption requirement of the mobile device puts unique demand in designing hardware and software components of the device. In this paper, we address the issue of minimizing the power consumption in retrieving the continuous media data from the disk drive for real-time playback purpose. Different from the legacy text based data, real-time multimedia playback requires that the storage supplies the data block continuous fashion. This may put immense burden on the power scarce environment since the disk Is required to be active for the entire playback duration. We develop elaborate algorithm which carefully analyzes the power consumption profile of the disk drive and which establishes the data retrieval schedule for the given playback. It computes the amount of data blocks to read, the length of active and standby period. According to our simulation result, the ARM algorithm exhibits superior performance in continuous media retrieval from the aspect of power consumption to legacy playback scheme.

• Progress in Superconductivity and Cryogenics
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• v.8 no.3
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• pp.54-58
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• 2006

In this paper, authors developed a real-time simulation algorithm for the power device application of HTS(High Temperature Superconducting) wire by using Real Time Digital Simulator(RTDS). At present, in order to extend the power capacity of some area where has a serious problem of power quality. especially metropolitan complex city, there are so many problems such as right of way for power line routes. space for downtown substations. and the environmental protection, etc. HTS technology can be useful to overcome this problem. Recently, according to the advanced HTS technology, the power application is being researched well. Simulation is required for safety before installation of HTS power cable, a fabrication model used at the power system simulation. This paper describes a real time digital simulation method for the application of HTS wire to power device. For the simulation analysis, test sample of HTS wire was actually manufactured. And the transient phenomenon of the HTS wire was analysed in the simulated utility power grid. This simulation method is the world first trial in order to obtain much better information for installation of HTS power device into a utility network.

• Journal of the Society of Disaster Information
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• v.19 no.4
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• pp.844-850
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• 2023

Purpose: This paper is about the development of a short-circuit protection power supply device using incandescent bulbs and its application for educational materials. This article, which considers electrical safety and energy conservation at the same time, has many kinds of potential applications for both educational and industrial areas. The above mentioned short-circuit protection power supply device using incandescent bulbs enhances safety and efficiency compared to normal current power supply devices. Additionally, as an educational materials, it can be used for electric safety training, and provides practical electrical safety knowledge on our actual life. Method: Using incandescent bulbs, design new type of short-circuit protection power supply device, and through verifying the function and safety of the device, make new type device, and applying it for an educational tool. Conclusion: This study is to develop new type of power supply device, and verify the possibility of the application for the device as an educational materials. Through this research, show an innovative solution, which contribute to electrical safety and energy conservation, and open the potential possibility on educational and industrial sectors.This kind of research is expected to contributes to enhanced research, and education on electrical safety and energy conservation management.

• Proceedings of the KIEE Conference
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• 2006.04a
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• pp.288-290
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• 2006

An efficiency improving method for Uninterruptible Power Supply System(UPS) was developed by using OP-AMP based application circuits such as voltage detection device, current detection device and static switch control device. The efficiency improving algorithm was made by mixing the operating concepts of On-Line type UPS with the operating concepts of Off-Line type UPS. The UPS' inverter does not work if the UPS' output load current is not higher than the low load operating current which is about 0-30(%) of the UPS' output load capacity. The low load operating current is adjustable within the half of the UPS' output load capacity. If the UPS' output load current is rising over than the low load operating current, the UPS' inverter starts working and the inverter output power feeds to the loads of UPS. If UPS' input power breaks out while UPS' inverter does not operate because the load current is low, the inverter starts working within 4(ms) with excessive output voltage which is ${\pm}$8(%) of normal UPS' output voltage. Like these. UPS can continuously feeds power to it's load device and reduce power consumptions.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.493-496
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• 2007

As the ubiquitous society period has set in recently, which resulted from both mass distribution of portable devices such as PDA, PMP, Smart Phones, the demand for more optional features of system and multimedia functions has been increasing. In compliance with thoses needs, the amount of information increased in a system and greater power capacities are needed more than ever. Therefore, in portable device which uses battery as a limited source of power, the power management has become a key factor in the system. This paper concentrates on the Power management solution for Smart device for the prevention of missing child. And ARM9 Core was used as CPU and Windows CE 5.0 was ported to the smart device.

• Journal of the Korean Society for Railway
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• v.7 no.4
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• pp.412-417
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• 2004

In urban rail transit systems, ground faults in the DC traction power supply system are currently detected by the potential relay, 64P. Though it detects the fault it cannot identify the faulted region and therefore the faulted region could not be isolated properly. Therefore it could cause a power loss of the trains running on the healthy regions and the safety of the passengers in the trains could be affected adversely. Two new ground fault protective relay schemes that can identify the faulted region are presented in this paper. A current limiting device, called Device X, is newly introduced in both system, which enables large amount of ground fault current flow upon the positive line to ground fault. One type of the relaying schemes is called directional and differential ground fault protective relay which uses the current differential scheme in detecting the fault and uses the permissive signal from neighboring substation to identify the faulted region correctly. The other is called ground over current protective relay. It is similar to the ordinary over current relay but it measures the ground current at the device X not at the power feeding line, and it compares the current variation value to the ground current in Device X to identify the correct faulted line. Though both type of the relays have pros and cons and can identify the faulted region correctly, the ground over current protective relaying scheme has more advantages than the other.

• Journal of Power Electronics
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• v.13 no.3
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• pp.390-399
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• 2013

As a result of the depletion of fossil fuels and environmental contamination, it has become important to use renewable energy. For the stable utilization of renewable energy sources, energy storage devices must be used. In addition, renewable and distributed power sources with energy storage devices must operate stably under grid-connected mode. This paper proposed dynamic response modeling for renewable power generation systems including a charger/discharger with an energy storage device in order to derive a method to guarantee stable operation while fully utilizing the energy from the energy storage device. In this paper, the principle operation and design guidelines of the proposed scheme are presented, along with a performance analysis and simulation results using MATLAB and PSIM. Finally, a hardware prototype of a 1kW power conditioning system with an energy storage device has been implemented for experimental verification of the proposed converter system.

• Journal of Magnetics
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• v.16 no.1
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• pp.51-57
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• 2011

A power supply for magnetic-stimulation devices was designed via a control algorithm that involved a start current application based on a resonant converter. In this study, a new power supply for magnetic-stimulation devices was designed by controlling the pulse repetition frequency and pulse width. The power density could be controlled using the start-current-compensation and ZCS (zero-current switching) resonant converter. The results revealed a high-repetition-frequency, high-power magnetic-stimulation device. It was found that the stimulation coil current pulse width and that pulse repetition frequency could be controlled within the range of 200-450 ${\mu}S$ and 200-900 pps, respectively. The magnetic-stimulation device in this study consisted of a stimulation coil device and a power supply system. The maximum power of the stimulation coil from one discharge was 130 W, which was increased to 260 W using an additional reciprocating discharge. The output voltage was kept stable in a sinusoidal waveform regardless of the load fluctuations by forming voltage and current control using a deadbeat controller without increasing the current rating at the starting time. This paper describes this magnetic-stimulation device to which the start current was applied.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.1
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• pp.59-64
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• 2016

This paper aims at the prototype-making of the intelligent switchgear with arc fault diagnosis function required to prevent the electrical fire. The main control unit of the intelligent switchgear consists of a single-phase power management device and a arc fault diagnosis device. The prototype of the single-phase power management device and the prototype of the arc fault diagnosis device in this paper. In the device, the cooperation function with the arc fault diagnosis device is developed to transmit the cause of the electrical fire to the remote server system.