• Journal of Electrical Engineering and Technology
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• v.3 no.3
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• pp.300-307
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• 2008

Event source locating is very important to improving the power quality level. This paper presents a method to determine the relative location of the voltage sag source according to the cause. For this, the concept of the relative location of the source is defined first. Then, the main causes of voltage sag are classified and their characteristics are discussed. From these investigations, the rules to determine the relative location of event source are proposed for each type and the overall algorithm to identify the relative location and the kind of event source is presented. Finally, the proposed method is applied to the IEEE 13-bus test system and it is verified that the method can help to pinpoint the accurate location of the event source.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.293-298
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• 2003

This study deals with the source location method of defect which can be occurred in structure. The existing methods was very difficult to be applied to predict it because of using very complex numerical formula. The triangulation method which was proposed in his study can predict the source location predicted easily with small amount of data. Wave arrival time data can be directly converted into source-sensor distance is known. For this purpose, the propagation velocity was measured by Rayleigh wave, and the propagation behavior was analyzed. For the consideration of jointed part in structure, the source location method was applied to the welded workpiece. The signal propagation velocity was measured in welding part for the purpose of application to the part and the revised algorithm of source location was proposed.

• Journal of the Korean Society of Safety
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• v.37 no.1
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• pp.1-11
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• 2022

This numerical study investigates the effects of the size of the natural smoke vent area (10% and 1% of the floor area) and the location of the fire source (i.e., at the side and center of the stage) on the temperature distribution in the compartment and velocity distribution and mass flow rate of flow through a natural smoke vent for a reduced-scale model of a theater stage. Then, the mass flow rate of outflow through the natural smoke vent in the event of a fire for a real-scale theater stage was examined. The case with the larger natural smoke vent area and central fire source location showed lower temperature distributions and higher mass flow rates of outflow and inflow than the case with the smaller natural smoke vent area and side fire source location. The trends of the temperature distributions were closely related to those of the mass flow rates for the outflow and inflow. Additionally, the case with the larger natural smoke vent area and central fire source location exhibited the most non-uniform flow velocity distribution in all cases tested. A bidirectional flow, in which the outflow and inflow occur simultaneously, was observed through the natural smoke vent. In the event of a fire situation in a real-scale theater stage, it was predicted that the case with the larger natural smoke vent area and central fire source location would have a mass flow rate of outflow that is 43.53 times higher than that of the case with the smaller natural smoke vent area and side fire source location. The present results indicate that the natural smoke vent location should be determined by considering the location in a theater stage where a fire can occur.

• Journal of the Korean Society for Nondestructive Testing
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• v.25 no.6
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• pp.475-482
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• 2005

The iterative calculation by least square method was used to determine the source location of acoustic emission in rock, as so called "traditional method". The results were compared with source coordinates infered from the application of neural network system for new input data, as so called "new method". Input data of the neural network were based on the time differences of longitudinal waves arrived from acoustic emission events at each transducer, the variation of longitudinal velocities at each stress level, and the coordinates of transducer as in the traditional method. The momentum back propagation neural network system adopted to determine source location, which consists of three layers, and has twenty-seven input processing elements. Applicability of the new method were identified, since the results of source location by the application of two methods were similarly concordant.

• Journal of the Korean Society for Nondestructive Testing
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• v.10 no.1
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• pp.84-90
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• 1990

By discriminating the wave propagation paths in cylindrical vessels, a technique for AE source location has been proposed. This method is based on the path difference between several propagating directions from a source to a sensor. One sensor can receive multiple waveforms sequentially including a direct arrival and several others propagated through the circumferential direction. An wave front normally propagates in all directions and as many waveforms can reach the sensor until the signal faded out by attenuation. Only the first four arrivals suffice the condition for calculating the source location. The proposed method was examined for an actual cylindrical vessel by the source location experiment using simulated AE sources. The test showed very promising results and the method can be utilized for a simple AE source location without multi-channel instruments.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.96-102
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• 2005

Acoustic Emission(AE) technique has been applied to not only material characterization evaluation but also on-line monitoring of the structural integrity. The AE source location technique is very important to identify the source, such as crack, leak detection. Since the AE waveforms obtained from sensors are very difficult to distinguish the defect signals, therefore, it is necessary to consider the signal analysis of the transient wave-form. In this study, we have divided the region of interest into a set finite elements, and calculated the arrival time differences between sensors by using the velocities at every degree from 0 to 90. A new technique for the source location of acoustic emission in fiberboard plates has been studied by introducing Wavelet Transform(WT) do-noising technique. WT is a powerful tool for processing transient signals with temporally varying spectra. If the WT de-noising was employed, we could successfully filter out the errors of source location in fiberboard plates by arrival time difference method. The accuracy of source location appeared to be significantly improved.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2002.04a
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• pp.369-375
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• 2002

The results of source location in terms of AE signal occurred by the spot exciting as suggested in this research, it has been confirmed that AE technique is quite fruitful in figuring out the location of the occurrence, form, size and direction of the defects. Thus, it is expected that the application of the experimental method suggested in this study would make it possible to identify, in the nondestructive way, the location of the defect in the material.

• Proceedings of the KIEE Conference
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• 2003.07a
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• pp.157-159
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• 2003

To improve power quality, it is important to find the location of disturbance source. This paper presents a method to find the location of disturbance source that leads to voltage sag. The relative location of the source is defined and the method to determine the relative location of voltage sag is proposed. With this method, this paper shows that the location of disturbance source can be identified under distributed monitoring system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.373-379
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• 2012

This paper presents a fault location algorithm based on the adaptively estimated value of the local sequence source impedance for faults on a parallel transmission line. This algorithm uses only the local voltage and current signals of a faulted circuit. The remote current signals and the zero-sequence current of the healthy adjacent circuit are calculated by using the current distribution factors together with the local terminal currents of the faulted circuit. The current distribution factors consist of local equivalent source impedance and the others such as fault distance, line impedance and remote equivalent source impedance. It means that the values of the current distribution factors can change according to the operation condition of a power system. Consequently, the accuracy of the fault location algorithm is affected by the two values of equivalent source impedances, one is local source impedance and the other is remote source impedance. Nevertheless, only the local equivalent impedance can be estimated in this paper. A series of test results using EMTP simulation data show the effectiveness of the proposed algorithm. The proposed algorithm is valid for a double-circuit transmission line system where the equivalent source impedance changes continuously.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.57-64
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• 2004

This study deals with the prediction of defect location which can be occurred in structure. The existing methods was very difficult to be applied to predict it, because of complex numerical formula. The triangulation method proposed in this study can predict the source location easily with small amount of data. The arrival time of wave can be directly converted into the distance between sensors. For this purpose, the propagation velocity was measured by Rayleigh wave, and the propagation behavior was analyzed. The welded workpiece is adapted to investigate for the consideration of jointed part in structure, The propagation velocity of signal was measured in welded workpiece and the revised algorithm of source location was proposed.