• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
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• pp.51-53
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• 2009

In wireless sensor networks(WSNs), geographic routing algorithms can enhance the network capacity. However, in the real WSNs, it is difficult for each node to know its accurate physical location. Geographic routing with location error may have serious problems such as disconnected links and delayed data transmission. In this letter, we present an efficient location error detection scheme for geographic routing. The proposed algorithm can efficiently update its incorrect location without additional procedure and finally enhance the performance on the geographic routing with the location errors.

• 대한임베디드공학회논문지
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• 제9권6호
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• pp.323-334
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• 2014

In this paper, we proposed indoor positioning system with improved accuracy. The proposed indoor location measurement system is based pedestrian location measurement method that use the embedded sensor of smartphone. So, we do not need wireless external resources, such as GPS or WiFi signals. The conventional methods measure indoor location by generating a movement route of pedestrian by step and direction recognition. In this paper, to correct the direction sensor error, we use the common feature of the normal indoor floor map that the indoor path is lattice-structured. And we quantize moving directions depending on the direction of indoor path. In addition, we propose moving direction measuring method using geomagnetic sensor and gyro sensor to improve the accuracy. Also, the proposed step detection method uses angle and accelerometer sensors. The proposed step detection method is not affected by the posture of the smartphone. Direction errors caused by direction sensor error is corrected due to proposed moving direction measuring method. The proposed location error correction method corrects location error caused by step detection error without the need for external wireless signal resources.

• 대한전기학회논문지:전력기술부문A
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• 제51권8호
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• pp.371-378
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• 2002

This paper presents the rapid and accurate algorithm for fault detection and location estimation in the transmission line. This algorithm uses wavelet transform for fault detection and harmonics elimination and utilizes least square error method for fault impedance estimation. Wavelet transform decomposes fault signals into high frequence component Dl and low frequence component A3. The former is used for fault phase detection and fault types classification and the latter is used for harmonics elimination. After fault detection, an adaptive data window technique using LSE estimates fault impedance. It can find a optimal data window length and estimate fault impedance rapidly, because it changes the length according to the fault disturbance. To prove the performance of the algorithm, the authors test relaying signals obtained from EMTP simulation. Test results show that the proposed algorithm estimates fault location within a half cycle after fault irrelevant to fault types and various fault conditions.

• 한국정보처리학회논문지
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• 제7권7호
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• pp.2169-2178
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• 2000

This paper proposes the structure of an agent and rules for fault detection and location on LAN. To find out a reason of critical fault incurred LAN, collision detection rule, error detection rule, broadcast detection rule, system location rule, and Internet application location rule ar shown. Also, the structure of multi-agent system and state transition diagram is portrayed to have connectivity with he set of rules. To verify availability of proposed rules, the process to find a faulty system is shown by monitoring and analyzing the LAN fault occurrences from the proposed set of rules. Such an rule based agent system is helpful to an Internet manager to solve a reason of fault and make ad decision from gathering management information.

• 전기학회논문지
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• 제65권10호
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• pp.1774-1779
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• 2016

This paper proposes a portable cable fault detection system with automatic fault distinction and distance measurement using time-frequency correlation and reference signal elimination method and automatic fault classification algorithm in order to have more accurate fault determination and location detection than conventional time domain refelectometry (TDR) system despite increased signal attenuation due to the long distance to cable fault location. The performance of the developed system method was validated via an experiment in the test field constructed for the standardized performance test of power cable fault location equipments. The performance evaluation showed that accuracy of the developed system is less than 1.34%. Also, an error of automatic fault type and location by detection of phase and peak value through elimination of the reference signal and normalization of correlation coefficient and automatic fault classification algorithm not occurred.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2015년도 추계학술대회
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• pp.842-846
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• 2015

본 연구에서는 세포의 자가 치료 기능을 모사하여 복잡한 디지털 회로를 기능별 분리시킨 구조에서 회로 동작 중 발생하는 오류 위치를 빠르게 찾고 복구 시키는 알고리즘 방법을 제안한다. 디지털 회로를 각 기능별로 9가지로 분리시켜 오류 난 디지털 회로의 기능블록 위치를 빠르게 검출할 수 있게 하며 복구 시키는 방법을 제안한다. 복잡한 구조의 디지털 회로에서도 각 디지털 회로의 기능 별 위치에 대한 번호 및 좌표를 $3{\times}3$ 행렬 구조로 확대시켜 오류 위치에 대아여 검출 및 복구가 가능한 알고리즘이다.

• 한국정보통신학회논문지
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• 제19권11호
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• pp.2745-2750
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• 2015

본 연구에서는 세포의 자가 치료 기능을 모사하여 복잡한 디지털 회로를 기능별 분리시킨 구조에서 회로 동작 중 발생하는 오류 위치를 빠르게 찾고 복구 시키는 알고리즘 방법을 제안한다. 디지털 회로를 각 기능별로 9가지로 분리시켜 오류 난 디지털 회로의 기능블록 위치를 빠르게 검출할 수 있게 하며 복구 시키는 방법을 제안한다. 복잡한 구조의 디지털 회로에서도 각 디지털 회로의 기능별 위치에 대한 번호 및 좌표를 $3{\times}3$ 행렬 구조로 확대시켜 오류 위치에 대하여 검출 및 복구가 가능한 알고리즘이다.

• Journal of Communications and Networks
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• 제14권4호
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• pp.396-409
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• 2012

With the proliferation of diverse wireless devices, there is an increasing concern about the security of location information which can be spoofed or disrupted by adversaries. This paper investigates the characterization and detection of location spoofing attacks, specifically those which are attempting to falsify (degrade) the position estimate through signal strength based attacks. Since the physical-layer approach identifies and assesses the security risk of position information based solely on using received signal strength (RSS), it is applicable to nearly any practical wireless network. In this paper, we characterize the impact of signal strength and beamforming attacks on range estimates and the resulting position estimate. It is shown that such attacks can be characterized by a scaling factor that biases the individual range estimators either uniformly or selectively. We then identify the more severe types of attacks, and develop an attack detection approach which does not rely on a priori knowledge (either statistical or environmental). The resulting approach, which exploits the dissimilar behavior of two RSS-based estimators when under attack, is shown to be effective at detecting both types of attacks with the detection rate increasing with the severity of the induced location error.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2006년도 하계학술대회
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• pp.53-56
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• 2006

WiBro service provider have made an effort to provide the subscriber's location and have deployed LBS system using cell-ID method. Cell-ID method has a location error problem if repeater is used on the other cell places at the same time. We introduce and analysis LMU(Location Measurement Unit) on the repeater fer location detection of subscriber which is serviced via the repeater. In this paper we propose the method using LMU on the repeater to avoid these location errors and to provide more exact location to the subscriber. we can conclude that the location error can be more exact at the building which uses repeater. It represents in which level the subscriber is serviced at the building.

• 상하수도학회지
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• 제30권3호
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• pp.253-261
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• 2016

A variety of methods for detecting the location of an underground water pipeline are being used across the world; the current main methods used in South Korea, however, have the problems of low precision and efficiency and the limitations in actual application. On this, this study developed locator capable of detecting the location of a water pipe by the use of an IMU sensor, and technology for using the extended karman filter to correct error in location detection and to plot the location on the coordinate system. This study carried out a tract test and a road test as basic experiments to measure the performance of the developed technology and equipment. As a result of the straight line, circular and ellipse track tests, the 1750 IMU sensor showed the average error of 0.08-0.11%; and thus it was found that the developed locator can detect a location precisely. As a result of the 859.6-m road test, it was found that the error was 0.31 m in case the moving rate of the sensor was 0.3-0.6 m/s; and thus it was judged that the equipment developed by this study can be applied to long-distance water pipes of over 1 km sufficiently. It is planned to evaluate its field applicability in the future through an actual pipe network pilot test, and it is expected that locator capable of detecting the location of a water pipe more precisely will be developed through research for the enhancement of accuracy in the algorithm of location detection.