• Journal of Institute of Control, Robotics and Systems
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• v.17 no.10
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• pp.955-959
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• 2011

In this paper, we assume that an output sensor of a ball and beam system is coupled with AC measurement noise. We propose an output feedback controller for a ball and beam system under measurement noise of feedback sensor. Measurement noise makes feedback signals distorted, and results in performance degradation or even system failure. Therefore, we need to design a robust controller to accommodate the possible measurement noise in the feedback information. Our controller is equipped with a gain-scaling factor to minimize the effect of measurement noise in output feedback information. We give an analysis of the controlled system and illustrate the improved control performance via simulation and experiment for a ball and beam system.

• Journal of the Korea Institute of Military Science and Technology
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• v.5 no.1
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• pp.15-23
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• 2002

Uncertainty components and evaluation of the system of pressure measurement are presented in this paper. Since early in 1980s, measurement uncertainty is getting more important due to ISO/IEC 17025, which is established for international test and calibration laboratories. Up to now it is true that accuracy, precision, error and etc. have been commonly used in industry to define the amount of error to the products and equipment, but these terms ought to be united into uncertainity in the future. This paper describes how to indicate measurement uncertainty and types of measurement errors, and then shows the evaluation result of measurement system using piezoelectric pressure transducers.

• 제어로봇시스템학회:학술대회논문집
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• 1993.10b
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• pp.261-264
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• 1993

To reconstruct the real 3-D shape from the 3-D measurement data from the multiple directions, the rconstruction of the object on the basis of the mosaic processing of the 3-D measurement data are proposed. In this method, to conduct the reconstruction, the connection points have to be identified among the over-lap area between adjacent 3-D data. In this study, the simple image matching method is adopted for the identification of connection points, and this method is verified from numerical experiments.

• Current Optics and Photonics
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• v.1 no.6
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• pp.587-597
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• 2017

The extraction of the valid measurement region from the interference fringe pattern is a significant step when measuring gear tooth flank form deviation with grazing incidence interferometry, which will affect the measurement accuracy. In order to overcome the drawback of the conventionally used method in which the object image pattern must be captured, an improved segmentation approach is proposed in this paper. The interference fringe patterns feature, which is smoothed by the nonlinear diffusion, would be extracted by the structure tensor first. And then they are incorporated into the vector-valued Chan-Vese model to extract the valid measurement region. This method is verified in a variety of interference fringe patterns, and the segmentation results show its feasibility and accuracy.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.6
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• pp.515-519
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• 2021

IEEE 1588 PTP is a precision time protocol in which two systems synchronize without the aid of GPS by exchanging packets including transmission/reception time information. In the time synchronization process, the propagation delay time can be calculated and the distance between the two systems can be measured using this. In this paper, we proposed a method to improve the distance measurement precision less than the modulation symbol period using the timing error information extracted from the preamble of the received packet. Computer simulations show that the distance measurement precision is proportional to the length of the preamble PN sequence and the signal-to-noise ratio.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.8
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• pp.3040-3053
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• 2015

Wideband code division multiple access (WCDMA), high speed packet access (HSPA) and HSPA+ are third generation partnership project (3GPP) standards. These systems are the major wireless communication standards. In order to test the performance of WCDMA/HSPA/HSPA+ signal in a base station, the measurement hardware is required to the evaluation of the transmitted signals. In this paper, the algorithm for the performance measurement of the WCDMA/HSPA/HSPA+ is proposed. Also, the performance of the measurement algorithm is used to evaluate the generated signal by the WCDMA/HSPA/HSPA+ signal generator. Generally, the algorithm of normal modems cannot be applied to the measurement system because the signal measurement equipment needs to guarantee the high accuracy. So, the WCDMA/HSPA/HSPA+ signal measurement algorithm for the accurate measurement is proposed. By the simulation, it is confirmed that the proposed measurement algorithm has good performance compared with the specification. Therefore, the proposed algorithm can be usefully applied to verify the performance of the measurement using the simulation.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.436-439
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• 2000

To interact with surroundings robots and other automated machines employ sensors. However, the sensors measurements are uncertain in some amount and this may limit the potential applications of machines. Varying surrounding conditions and noises of sensor signals are major sources of the uncertainty. In this paper the uncertainty is tried to be reduced by using redundant sensor systems, where the redundancy is accomplished by varying the parameters of logically defined sensors. The target value redundantly measured is estimated adaptively. An experiment was done for measuring the stereoscopic 3D position measurement in an inconsistent light condition.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.369-370
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• 2006

• International Journal of Naval Architecture and Ocean Engineering
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• v.10 no.5
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• pp.596-608
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• 2018

The present study aims to assess test uncertainty assessment method of nominal wake field measurement by a Stereoscopic Particle Image Velocimetry (SPIV) system in a towing tank. The systematic uncertainty of the SPIV system was estimated from repeated uniform flow measurements. In the uniform flow measurement case, time interval between image frames and uniform flow speed were varied to examine the effects of particle displacement and flow around the SPIV system on the systematic standard uncertainty. The random standard uncertainty was assessed by repeating nominal wake field measurements and the estimated random standard uncertainty was compared with that of laser Doppler velocimetry. The test uncertainty assessment method was applied to nominal wake measurement tests of a very large crude oil carrier model ship. The nominal wake measurement results were compared with existing experimental database by other measurement methods, with its assessed uncertainty.

• Journal of Institute of Control, Robotics and Systems
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• v.20 no.11
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• pp.1136-1141
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• 2014

This paper proposes a new contact type ball tracking sensor to improve the control performance of a low cost ball-and-beam system. It is well-known that the impulsive measurement noise contained in ball position measurement is one of the factors which severely degrades the ball-and-beam control performance. The impulsive ball position measurement noises often appear under the sporadical ball floating on the beam. This fact motivates us to devise a simple analog preprocessing circuit to determine whether the ball loses the contact or not. Once the abnormal ball position measurement is detected, the design problem of the ball tracking sensor can be cast into the typical state estimation problem with missing data. In order to tackle the real-time implementation issue, a steady-state Kalman filter is applied to the problem. Through the experimental results, the usefulness of the proposed scheme is demonstrated.