• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.558-563
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• 1992

Bearing information of target is used critically for target tracking in underwater environment. In passive sonar, target bearing measurements are obtained by processing the acoustic signal emanating from the target. PDA tracking algorithm is usually applied in this case since bearing measurements have several peaks due to interference with other acoustic sources or reflections from underwater media. In this paper, we propose a modified PDA algorithm adopting new probabilistic distributions of the number, position, and amplitude of peaks based on the analysis of real data. This algorithm is tested on real and artificially generated data. The computer simulation result shows improvement of the tracking performance.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.129-137
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• 2012

This thesis introduced an azimuth tracking prismatic daylighting system. The system improved several issues of the previous passive prismatic daylighting system: low efficiency at sunrise and sunset, glare effect and polarized. The system was developed to track the movement of sun with azimuth tracking device, and it has its own power from the attached solar cells. We compared the with previous passive one in terms with system efficiency and daylighting factors(DF).

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.6
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• pp.608-614
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• 2008

This paper describes a location tracking system to guide landing process of an Unmanned Helicopter(UMH) exploiting MIT Cricket nodes. For automatic landing of a UMH, a precise positioning system is indispensable. However, GPS(Global Positioning System) is inadequate for tracking the three dimensional position of a UMH because of large positioning errors. The Cricket systems use Time-Difference-of-Arrival(TDoA) method with ultrasonic and RF(Radio Frequency) signals to measure distances. They operate in passive mode in that a listener attached to a moving device receives distance signals from several beacons located at fixed points on ground. Inevitably, this passive type of implementation causes large disturbances in measuring distances between beacons and the listener due to wind blow from propeller and turbulence of UMH body. To cope with this problem, we proposed active type of implementation for positioning a UMH. In this implementation, a beacon is set up at UMH body and four listeners are located at ground area at least where the UMH will land. A pair of Ultrasonic and RF signals from the beacon arrives at several listeners to calculate the position of the UMH. The distance signals among listeners are synchronized with a counter value appended to each distance signals from the beacon.

• Proceedings of the IEEK Conference
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• 2009.05a
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• pp.97-99
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• 2009

Bilateral teleoperation systems, connected to computer networks such as Internet have to deal with the time delay varying depending on factors such as congestion, bandwidth or distance. And the entire system is easy to become unstable due to irregular time delay. Passivity concept has been using as a framework to solve the stability problem in bilateral control of teleoperation. Acontrol scheme for teleoperation systems with varying time delay is proposed based on a passivity concept is proposed in this paper. One approach makinguse of the characteristic impedances is proposed to achieve a passive control. Since passive control does not mean that the system performance will be acceptable, another transmission scheme which focuses on both the passive feature and the acceptable performance is configured for varying time delay in this paper. The tracking performance has been proved through the computer simulation for varying time delay bilateral teleoperation system using Matlab Simulink.

• The Journal of the Acoustical Society of Korea
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• v.40 no.2
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• pp.109-120
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• 2021

This paper proposes the H∞ norm based data association gate method to apply robustly the data association gate of passive sonar automatic target tracking which is on non-linear targets in dense cluttered environment. For target tracking, data association method selects the measurements within validated gate, which means validated measuring extent, as candidates for the data association. If the extent of the validated gate in the data association is not proper or the data association executes under dense cluttered environment, it is difficult to maintain the robustness of target tracking due to interference of clutter measurements. To resolve this problem, this paper proposes a novel gating method which applies H∞ norm based bisection algorithm combined with 3-σ gate method under Gaussian distribution assumption and tracking error covariance. The proposed method leads to alleviate the interference of clutters and to track the non-linear maneuvering target robustly. Through analytic method and simulation to utilize simulated data of horizontal and vertical bearing measurements, improvement of data association robustness is confirmed contrary to the conventional method.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.7
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• pp.536-542
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• 2016

To enhance tracking efficiency, a target-tracking filter with a resource management algorithm is required. One of the resource management algorithms chooses or evaluates the proper sampling time using cost functions which are related to the target tracking filter. We propose a resource management algorithm for bearing only tracking environments. Since the tracking performance depends on the system observability, the bearing-only tracking is one of challenging target-tracking fields. The proposed algorithm provides the adaptive sampling time using the variation rate of the error covariance matrix from the target-tracking filter. The simulation verifies the efficiency performance of the proposed algorithm.

• The Journal of Society for e-Business Studies
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• v.16 no.3
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• pp.113-127
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• 2011

An RFID system has been widely applied in many areas over the initial SCM application. In the literature enormous RFID applications in healthcare are documented to improve patient safety, patient/provider logistics, and the efficiency of collecting data. Based on the proposed 4-layered RFID system architecture, we introduce a case that implemented an UHF passive RFID-based tracking system in an outpatient clinic. Particularly, we propose a method to process RFID data that contains noise and missing reads. The proposed method for processing unreliable RFID data is capable to locate the tag accurately and provide additional business information. We finally conclude the paper with identifying obstacles and what is necessary to ensure system reliability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2006.05a
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• pp.430-433
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• 2006

Wireless sensor network plays a prominent role in tracking the location of the target outdoor and indoor. This paper describes the implementation of the passive indoor location tracking system using ultrasonic and RF technologies that provides accurate location in the form of user space and position in three dimensions. Our system used a combination of RF and ultrasonic technologies to provide a location-support service to users and applicants. Ceiling-mounted beacons were spread through the building, publishing location information on an RF signal. The person carried a listener and the listener determined the location by calculating the distance from three beacons using triangulation algorithm.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.6
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• pp.1119-1123
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• 2006

Wireless sensor network plays a prominent role in tracking the location of the target outdoor or indoor. This paper describes the implementation of the passive indoor location tracking system using ultrasonic and RF technologies that provides accurate location in the form of user space and position in three dimensions. Our system used a combination of RF and ultrasonic technologies to provide a location-support service to users and applicants. Ceiling-mounted beacons were spread through the building, publishing location information on an RF signal. The person carried a listener and the listener determined the location by calculating the distance from three beacons using triangulation algorithm.

• The Journal of the Acoustical Society of Korea
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• v.20 no.1E
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• pp.7-13
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• 2001

In this paper we propose a new subspace tracking algorithm based on the PASTd (Projection Approximation Subspace Tracking with deflation). The algorithm is obtained via introducing the variable forgetting factor which adapts itself to the time-varying subspace environments. The tracking capability of the proposed algorithm is demonstrated by computer simulations in an abruptly changing DOA scenario. The estimation results of the variable forgetting factor PASTd(VFF-PASTd) outperform those of the PASTd in the nonstationary case as well as in the stationary case.