• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.179-180
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• 2006

The real time monitoring of the power systems covering wide area are essential for the stable operation and control of the power system. Synchronized phasor measurement is a key for the precise monitoring and control of the power systems. In this paper, to suggest an appropriate network topology of Power Infrastructure Defense System(PIDS) and to estimate the maximum network bandwidth with using the network analyzer, we simulate a PIDS and analyze the network traffic.

• Women's Health Nursing
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• v.16 no.4
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• pp.409-418
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• 2010

Purpose: The purpose of this study was to identify the effects of a pre-operation video assisted education program on residual urine, gas passing and state anxiety in women undergoing hysterectomy. Methods: Nonequivalent control group non-synchronized design was used for the study. In the research, video assisted education program was applied to the experimental group while a similar conventional education was done to the control group. The pre-operation state anxiety and post-operation residual urine and gas discharge of both the groups were measured. The data were analyzed using SPSS. Results: The experimental group was significantly higher than control group on gas passing (t=3.04, p=.00). However the residual urine (t=0.34, p=.73) and state anxiety (t=0.81, p=.82) did not make significant differences. Conclusion: This study is very meaningful in that it developed and provided a nursing intervention can positively affect hysterectomy patients. The pre-operation video assisted education program may be an effective nursing intervention that is clinically practical and useful to reduce time of the gas passing of hysterectomy patients after the operation.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.559-571
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• 2008

Platform Screen Door(PSD) has been installed and operated at seoul subway line $1\sim4$ in the manual train operation mode(ATS/ATC) by SeoulMetro since 2005. SeoulMetro uses the wireless (RF) communication system and the train door detection system for the link between the train and PSD doors opening/closing motion in the manual train operation mode. For the convenience and safety of passengers, the train doors and the PSD doors opening/closing shall be synchronized as much as possible. In ATO(Automatic Train Operation) mode which provides the interface between train control system and PSD system, ATO signaling system makes the train doors and PSD doors open/close command signals systematically, so PSD doors can be opened/closed almost simultaneously with the train doors. But, in the manual train control(ATS/ATC) mode, PSD system needs to detect the train doors open/close operation and make PSD open/close command signals to actuate PSD doors. These PSD open/close commanding process cause time delay of PSD doors opening/closing motion in response to the train doors opening/closing motion. Sometimes the response delay time can be over 1 second, which is not proper to operate PSD, and need to be reduced This paper presents the reduction method of the PSD response delay time to improve the convenience and safety of passengers.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.3
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• pp.332-341
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• 2013

SCADA RTU is a remote control unit equipped in substations for automatic operation of a power system. The RTU monitors and measures the operation status of remote substations to transmits the signals to upper SCADA system and receives control command signals from dispatch center to actuate corresponding apparatus. The RTU receives the standard time from GPS receiver to synchronize the times for all devices and acquires the status event of power apparatus using DIM. Without the time synchronization between GPS and RTU, stable operation of the power system and accurate analysis of the system fault are impossible due to the time error of SOE. In this paper, a test is performed to identify if the operation time of SCADA RTU DIM coincides with the standard time. And we tried to find the reason of error, to minimize the time discrepancy. Through this study, RTU operation time could be synchronized with the standard time within 10[ms] to improve the reliability of SOE data.

• The Journal of the Acoustical Society of Korea
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• v.19 no.3
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• pp.11-19
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• 2000

This research deals with the implementation procedures of a chorus processing DSP for karaoke system. It is necessary to compress the chorus data to store as many choruses as we can. We apply MPEG-1 audio algorithm to compress the chorus data. And the chorus system must be accompanied with the karaoke that can change the key and the tempo. So the chorus DSP must be able to change the key and tempo of the chorus data. We apply SOLA (Synchronized Overlap and Add) to do it. We designed the chorus DSP that can compress the chorus, change the key and tempo. And we verified the chorus DSP logic using FPGA. The used FPGA are two FLEX10K100s made by ALTERA. Finally we make the ASIC chip of chorus DSP and verify its operation.

• Journal of Satellite, Information and Communications
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• v.10 no.1
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• pp.71-76
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• 2015

In this paper, we developed the hardware GPS signal generator for generating a satellite navigation signal synchronized with Live GPS signal signals and analyzed the performance of signal genterator thorough the experiment For a hardware implementation of the GPS navigation signal synchronous generator, the GPS module may receive a GPS signal in order to generate the same signal as the operation that is transmitted from the current GPS satellite and the synchronized time information and the GPS satellites using the Novatel Inc. OEMStar.In. For generating the GPS synchronization signal, the GPS navigation signal generator was adjusted to a reference clock using the GPS clock synchronous information provided by the GPS receiving module and GPS signals also generated in consideration of the delay of the internal hardware of the generator. In this paper, we analyzed the effect of the receiver via the signal switching between Live GPS signal and generates a signal to measure the performance of the GPS navigation synchronization signal generator. It was confirmed that by the seamless operation of the signal even the moment that the switching of the generated signal from Live GPS signal has occurred through experimentation.

• Proceedings of the KIPE Conference
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• 2004.07b
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• pp.660-664
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• 2004

The indirect rotor position detection method using terminal voltage of brushless DC motor (BLDCM) requires simple control circuit, and has wide speed range of sensorless operation. However, because the substantial phase difference exists between real back emf and terminal voltage, the existing indirect detection method using analog filter which is affected by frequency, speed, and load sensitively cannot be synchronized with current, in the end, it advances or delays. This paper presents new analog filter circuit design for rotor position estimation in order to solve the problem, and proposes novel sensorless operation method which is stable even in high speed range and not influenced by parameters with analysis on phase difference by load and speed. Moreover, the appropriateness of the proposed sensorless drive in this paper is verified and analyzed by experimentation.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.283-287
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• 1989

This paper presents a microprocesser based Self-Controller for a Permanent Magnet Synchronous Motor(PMSM), fed by voltage soure inverter. The proper operation of the PMSM can be ensured only if the stator current is always synchronized with the its Back-E.M.F. The use of incremantal encoder with high resolution makes it possible to design a Self-Control led P.W.M. inverter. The pulse ratios are controlled to reduce the torque ripple in the low-speed drive region. And during the operation, torque - speed characteristics are improved by the control of optimal load angle.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.228-231
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• 2008

For a satellite data communication, the technology of frame synchronization is widely used between a sender and a receiver. Last year, we suggested zero-loss frame synchronization [1] using pattern search and using bits threshold search algorithm that is based on SIMD technology [2,3]. This algorithm could solve both of hardware and software drawbacks, which are frame loss and low processing performance. However, this algorithm didn't optimize the processing of output data, synchronized data, which caused overhead to the memory allocation and the memory copy. Consequently, the performance of the frame synchronizer application was degraded. In this paper, we enhance previous work using a circular buffer in order to optimize the output data processing. The performance comparison with the previous algorithm shows that the enhanced proposed approach dramatically outperforms in the output data processing speed.

• Proceedings of the Safety Management and Science Conference
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• 2012.04a
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• pp.159-166
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• 2012

Recently, by the whole world paradigm shift to "Low Carbon Green Growth", it is required to renovate National Transportation and Logistics System. Transportation accounts for 21% of the total energy consumption and 20% of the total $CO_2$ emission, and also places its main reliance on fossil fuels. From green point of view, electric railway system is superior to the other transportation alternatives, but also required to develop the innovative technologies for high efficiency and low energy consumption. In this paper, the concept of railway green operation system by regenerative synchronized driving is presented, including the numerical example and the estimated effect.