• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.60 no.4
• /
• pp.805-810
• /
• 2011

This paper deals with the method and algorithm used to find fault locations in gas insulated transmission line. The method uses UHF sensors and digital oscilloscope to detect discharge signals emitted to the outside through insulating spacer in the event of breakdown inside GIL. UHF sensors are the external type and installed at outside of insulating spacers of GIL. And we used wavelet signal processing to analyze the discharge signals and confirm the exact fault location findings in the GIL test line. This method can overcome demerit of TDR(Time Domain Reflectometer) method having been applied to detect fault location for conventional underground transmission lines, and Ground Fault Sensors used in conventional GIS systems. TDR method requires high level of specialty and experience in analyzing the measured signals. Ground fault sensors are installed inside GIL and can be destroyed by high transient voltage. This paper's method can simplify the fault location process and minimize the damage of sensors. In addition, this method can estimate the fault location only by the time difference when discharge signals are arrived to detecting sensors at the ends of GIL sections without reasons of breakdown. To test the performance of our method, we installed sensors at the ends of test line of GIL(84m) and sensed discharge signals occurred in GIL, energized with AC voltage generator up to 700kV.

• Proceedings of the KIEE Conference
• /
• 2001.07d
• /
• pp.2178-2180
• /
• 2001

This paper is the study for the separating noise signal that is the greatest problem in ultrasonic signal measurement which is one of the method of estimation of partial discharge signals location. Because we can measure the number and location of signal, it is possible to distinguish between the signal of partial discharge and the external noise. Therefore, we can develop the credibility of detecting of insulating deterioration in transformer.

• Journal of Digital Contents Society
• /
• v.16 no.2
• /
• pp.179-187
• /
• 2015

Spread of smartphone creates various contents. Among many contents, AR application using Location Based Service(LBS) is needed widely. In this paper, we propose error correction algorithm for location-based Augmented Reality(AR) system using computer vision technology in android environment. This method that detects the early features with SURF(Speeded Up Robust Features) algorithm to minimize the mismatch and to reduce the operations, and tracks the detected, and applies it in mobile environment. We use the GPS data to retrieve the location information, and use the gyro sensor and G-sensor to get the pose estimation and direction information. However, the cumulative errors of location information cause the mismatch that and an object is not fixed, and we can not accept it the complete AR technology. Because AR needs many operations, implementation in mobile environment has many difficulties. The proposed approach minimizes the performance degradation in mobile environments, and are relatively simple to implement, and a variety of existing systems can be useful in a mobile environment.

• Smart Structures and Systems
• /
• v.23 no.1
• /
• pp.61-69
• /
• 2019

Offshore structures are generally exposed to harsh environments such as strong tidal currents and wind loadings. Monitoring the structural soundness and integrity of offshore structures is crucial to prevent catastrophic collapses and to prolong their lifetime; however, it is intrinsically challenging because of the difficulties in accessing the critical structural members that are located under water for installing and repairing sensors and data acquisition systems. Virtual sensing technologies have the potential to alleviate such difficulties by estimating the unmeasured structural responses at the desired locations using other measured responses. Despite the usefulness of virtual sensing, its performance and applicability to the structural health monitoring of offshore structures have not been fully studied to date. This study investigates the use of virtual sensing of offshore structures. A Kalman filter based virtual sensing algorithm is developed to estimate responses at the location of interest. Further, this algorithm performs a multi-sensor data fusion to improve the estimation accuracy under non-stationary tidal loading. Numerical analysis and laboratory experiments are conducted to verify the performance of the virtual sensing strategy using a bottom-fixed offshore structural model. Numerical and experimental results show that the unmeasured responses can be reasonably recovered from the measured responses.

• Journal of Satellite, Information and Communications
• /
• v.12 no.1
• /
• pp.64-71
• /
• 2017

In this paper, Kalman filter and RRWA algorithm are used to estimate the accurate target in IR-UWB (Impulse-Radio Ultra Wideband) radar system, which enables accurate location recognition of indoors and outdoors with low cost and low power consumption. In the signal reflected by the target, unnecessary signals exist in addition to the target signal. We have tried to remove unnecessary signals and to derive accurate target signals and improve performance. The location of the targets is estimated in real time with one transmitting antenna and one receiving antenna. The Kalman filter was used to remove the background noise and the RRWA algorithm was used to remove the reflected signal. In this paper, we think that it will be useful to study the accurate distance estimation and tracking in future target estimation.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.23 no.5
• /
• pp.13-22
• /
• 2019

In order to evaluate the earthquake damage level of small and medium - sized bridges without earthquake monitoring system, we proposed an algorithm for estimating the seismic force at the target bridge location using the ground acceleration data from the earthquake observatories near the structure. In general, response spectrum analysis, which is the most widely used dynamic analysis method to design and evaluate the structural system numerically is required a response spectrum to determine the dynamic loading. In this study, selection methods of the three closest observatories from the target structure and estimation method of ground response spectrum at arbitrary locations are developed. The proposed method can consider the distance and phase between the target bridge and the seismic station and from the relationship between the acceleration amplitudes and the location of the selected seismic station, the earthquake loading of the target bridge can be determined. The proposed algorithm is estimated to be more conservative than the response spectrum evaluated by actual earthquake data.

• Atmosphere
• /
• v.25 no.3
• /
• pp.569-573
• /
• 2015

An algorithm to symmetric radius of $15ms^{-1}$ isotaches of tropical cyclones is suggested using infrared (IR) imagery of geostationary satellite. It is assumed that symmetric tangential winds outside the maximum winds exponentially decrease with the radial distances of the tropical cyclone, which has a clear eye-wall structure. Four parameters for estimation of the tropical cyclone size are center location, maximum sustained wind, radius of the maximum wind, and relaxation coefficient for the decreasing rate with distances of the tropical cyclone. The estimation results are limitedly verified as comparing to surface winds of polar orbiting satellite such as ASCAT data.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• v.1
• /
• pp.485-489
• /
• 2006

In last decades, several linearization methods for the AOA measurements have been proposed, for example, Gauss-Newton method and closed-form solution. Gauss-Newton method can achieve high accuracy, but the convergence of the iterative process is not always ensured if the initial guess is not accurate enough. Closed-form solution provides a non-iterative solution and it is less computational. It does not suffer from convergence problem, but estimation error is somewhat larger. This paper proposes a self-tuning weighted least square AOA algorithm that is a modified version of the conventional closed-form solution. In order to estimate the error covariance matrix as a weight, two-step estimation technique is used. Simulation results show that the proposed method has smaller positioning error compared to the existing methods.

• Proceedings of the IEEK Conference
• /
• 2002.07a
• /
• pp.141-144
• /
• 2002

In this paper, we propose a new object tracking algorithm using deformed template and Level-Set theory, which is robust against background variation, object flexibility and occlusion. The proposed tracking algorithm consists of two steps. The first step is an estimation of object shape and location, on the assumption that the transformation of object can be approximately modeled by the affine transform. The second step is a refinement of the object shape to fit into the real object accurately, by using the potential energy map and the modified Level Set speed function. Experimental results show that the proposed algorithm can track non-rigid objects with large variation in the backgrounds.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.19 no.5
• /
• pp.219-225
• /
• 2024

In this study, an algorithm was developed to measure the volume of meat products passing through the conveyor line of a portion cutter using a stereo vision sensor and calculate the cutting position to cut them into the same weight unit. Previously, three or more laser profile sensors were used for this purpose. However, in this study, the volume was measured using four stereo vision sensors, and the accuracy of the developed algorithm was verified to confirm the applicability of the technique. The technique consists of stereo correction, scanning and outlier removal, and cutting position calculation procedures. The comparison between the volume measured using the developed algorithm and the results measured using an accurate 3D scanner confirmed an accuracy of 91%. Additionally, in the case of 50g target weight, where the cutting position calculation is crucial, the cutting position was calculated at a speed of about 2.98 seconds, further confirming the applicability of the developed technique.