• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.955-961
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• 2016

Fault location estimation is an important element for rapid recovery of power system when fault occur in transmission line. In order to calculate line impedance, most of fault location algorithm uses by measuring relaying waveform using DFT. So if there is a calculation error due to the influence of phasor by DC offset component, due to large vibration by line impedance computation, abnormal and non-operation of fault locator can be issue. It is very important to implement the robust fault location algorithm that is not affected by DC offset component. This paper describes an enhanced fault location algorithm based on the DC offset elimination filter to minimize the effects of DC offset on a long transmission line. The proposed DC offset elimination filter has not need any erstwhile information. The phase angle delay of the proposed DC offset filter did not occurred and the gain error was not found. The enhanced fault location algorithm uses DFT filter as well as the proposed DC offset filter. The behavior of the proposed fault location algorithm using off-line simulation has been verified by data about several fault conditions generated by the ATP simulation program.

• Journal of Communications and Networks
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• v.7 no.2
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• pp.207-221
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• 2005

The proliferation of wireless local area networks (WLANs) offering high data rate in hot spot area have spurred the demand for possible WLANs and third-generation (3G) cellular network integration solutions as the initiative step towards 4G systems. This paper provides a novel architecture for seamless location-aware integration of WLANs into 3G cellular networks and also an analysis for the efficient handover techniques. We introduce location as a key context in secure roaming mechanism for context-aware interworking in 4G systems. The fast secure roaming with location-aware authentication is implemented at an entity called location-aware service (LAS) broker that utilizes the concepts of direction of user and pre-warming zone. The location-ware interworking architecture supports seamless roaming services among heterogeneous wireless networks including WLANs, wireless metropolitan area networks (WMANs), and 3G cellular networks. This paper also includes a description of procedures needed to implement efficient mobility and location management. We show how the LAS broker with pre-warming and context transfer can obtain significant lower latency in the vertical handover.

• Communications for Statistical Applications and Methods
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• v.11 no.1
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• pp.153-160
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• 2004

In recent years, the size of data set which we usually handle is enormous, so a lot of outliers could be included in data set. Therefore the robust procedures that automatically handle outliers become very importance issue. We consider the robust estimation problem of location parameter in the univariate case. In this paper, we propose a new method for defining robustness weights for the weighted mean based on the median distance of observations and compare its performance with several existing robust estimators by a simulation study. It turns out that the proposed method is very competitive.

• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.312-314
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• 2005

We have implement indoor positioning system to supply orientation information, We have used ultrasound in indoor positioning system for distance and orientation measurements, then propose a set of methods to calculate orientation from an array of well placed ultrasonic sensors operating in the indoor positioning system, We have design and implement a indoor positioning system using a combination of hardware and software and demonstrate end-to-end functionality of the system, We have implement ZigBee based home automation system using location-aware System.

• Communications for Statistical Applications and Methods
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• v.20 no.4
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• pp.241-246
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• 2013

In this study, we propose a nonparametric simultaneous test procedure for the location translation and scale parameters. We consider the Wilcoxon rank sum test for the location translation parameter and the Mood test for the scale parameter with the quadratic and maximal types of combining functions. Then we derive the limiting null distributions of the combining functions. We illustrate our procedure with an example and compare efficiency by obtaining the empirical powers through a simulation study. Finally, we discuss some interesting features related to the nonparametric simultaneous tests.

• Proceedings of the Korea Contents Association Conference
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• 2006.11a
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• pp.430-433
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• 2006

A RFID technology that process information of tag attaching in physical object by a point technology that enable this Ubiquitous computing through radio frequency is noted. One of our most important, location tracking for object in RFID system. With this in mind, proposed EPCglobal network gives the location tracking and location services. but, RFID system has the drawbacks. That is special construction and components be positively necessary for RFID system. The service difficult to integrate other service and it increases costs considerably. This thesis gives location service using RFID based on SIP in hospital.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.369_370
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• 2009

This paper describes the fault location method for HVDC submarine cables. Most conventional fault location methods can be applied in off-line. However, in this paper, on-line fault location algorithm is proposed using multi-scale correlating of wavelet coefficient and travelling wave. The propagation velocity is measured by field test on Jeju-Heanam submarine cable section. Finally, the fault location algorithm is tested by same system modeling using EMTP/ATP.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.478-480
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• 2005

본 논문에서는 모바일 셀룰러 네트워크상에서 다양한 이동 단말 이동성을 이용한 동적인 Location Update 기법을 제안한다. 동적인 Location Update 기법에서는 다양한 이동 단말들의 이동 패턴을 고려하기 위해서 Differentiated-Walk Model을 이용하고 그 모델에서 제공하는 핸드오프 확률과 이동성 등급을 이용하여 LA(Location Area)를 형성한다. LA는 사용자의 이동 패턴을 고려하여 동적으로 형성되며 본 논문에서는 이러한 LA를 기반으로 제공되는 페이징 기법을 제안한다.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.256-259
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• 2004

Recently, Location-based services(LBS) allow consumers to receive services based on their geographic location data. Users want to take services based location information with portable devices. And Point of Interest(POI) information's usage is increasing with mobile device's development and user's interest. And this paper shows that we connect the multimedia POI database(DB), provide the multimedia services through the portable devices and search POI using location and direction information. The multimedia POI is consisted of sound, image, moving image and animation with location information. When we search POI, we find POI in DB using the area zone and direction information.[l]

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.1
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• pp.18-24
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• 2016

In order to service restoration and enhance power system reliability, a number of impedance based fault location algorithms have been developed for fault locating in a transmission line. This paper presents an advanced impedance-based fault location algorithms in a two-ended sources transmission line to reduce the DC offset error effects. This fault location algorithm uses of the GPS time synchronized voltage and current signals from the local and remote terminal. The algorithm uses an advanced DC offset removal filter. A series of test results using ATPdraw simulation data show the performance effectiveness of the proposed algorithm. The proposed algorithm is valid for a two-end sources transmission network.