Yong-June Shin

Yonsei University, Sŏul, Seoul, South Korea

Are you Yong-June Shin?

Claim your profile

Publications (27)19.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: A new method to estimate the average dielectric constants of cable sections that have undergone aging is proposed. By comparing the experimental Joint Time-Frequency Domain Reflectometry waveform signatures from a new and an aged cable of the same type, it is demonstrated that the change in the average dielectric constant of the insulation material due to aging can be estimated. For example, for a cable containing Cross-Linked Polyethylene insulation, accelerated aging tests based on the modified Arrhenius equation that simulate 120 years of aging at 50 °C operating temperature show that the dielectric constant of the insulation decreases by more than 34.5%. The same tests performed on another cable containing Ethylene-Propylene Rubber insulation show that the average dielectric constant of the insulation decreases by 10.4%. The efficacy of the method is further demonstrated by estimating the increase in the average dielectric constant of a wedge section of a cable that contained water intrusion.
    Journal of Electromagnetic Waves and Applications 01/2014; 28(7). · 1.40 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents a novel ultrasonic guided wave based inspection methodology for detecting and evaluating gas accumulation in nuclear cooling pipe system. The sensing is in-situ by means of low-profile permanently installed piezoelectric wafer sensors to excite interrogating guided waves and to receive the propagating waves in the pipe structure. Detection and evaluation is established through advanced cross time-frequency analysis to extract the phase change in the sensed signal when the gas is accumulating. A correlation between the phase change and the gas amount has been established to provide regulatory prediction capability based on measured sensory data.
    Proc SPIE 03/2012;
  • [Show abstract] [Hide abstract]
    ABSTRACT: For efficient maintenance of a diverse fleet of aging air- and rotorcraft, effective condition based maintenance (CBM) must be established based on rotating components monitored vibration signals. Traditional linear spectral analysis techniques of the vibration signals, based on auto-power spectrum, are used as common tools of rotating components diagnoses. Unfortunately, linear spectral analysis techniques are of limited value when various spectral components interact with one another due to nonlinear or parametric process. In such a case, higher order spectral (HOS) techniques are recommended to accurately and completely characterize the vibration signals. Since the nonlinearities result in new spectral components being formed with coherency in phase, the detection of such phase coherence may be carried out with the aid of higher order spectra. In this paper, we use the bispectrum as a higher order spectral analysis tool to investigate nonlinear wave-wave interaction in vibration signals. Accelerometer data has been collected from baseline tests of accelerated conditioning in tail rotor drive-train components of an AH-64 helicopter drive-train research test bed simulating drive-train conditions. Through bispectrum analysis, we compare the harmonics interaction patterns contained in vibration signals from different physical setting of helicopter drive train and compare that with classical power spectral density plots. The analysis advances the development of higher order statistics and two dimensional frequency health indicators in order to qualify health conditions in mechanical systems.
    IEEE Aerospace Conference Proceedings 01/2012;
  • D. Coats, M.N. Alam, Qiu Deng, M. Ali, Yong-June Shin
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we present a time-frequency based reflectometry solution that focuses on the practical implementation of in-situ and non-destructive cable diagnostic tests. Towards this ideal health monitoring approach, we have explored the implementation of alternative monitoring techniques using surface wave injection for monitoring of cable insulation health toward nondestructive tests. Through use of surface wave propagation, a diagnostic signal can be injected in control, instrumentation, and power cable without removing installed samples under test. However, in practical implementation of surface wave tests through antenna, problems are presented in the form of dispersive media distorting the response of the frequency sweeping reference signal in either frequency or time-frequency domains. We present an optimal reference signal and time-frequency cross correlation diagnostic and prognostic algorithm to allow for implementation of joint time-frequency domain reflectometry (JTFDR) in minimal bandwidth to reduce attenuation in surface wave reflectometry.
    Information Science, Signal Processing and their Applications (ISSPA), 2012 11th International Conference on; 01/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: In order to properly suppress the harmonic current in a power system, the harmonic similarity metric is developed in this paper and used to establish an efficient strategy for harmonic filter placement. To validate the strategy, an industrial distribution system is analyzed under two harmonic current injection scenar- ios. It is demonstrated that the proposed strategy has a robust ability to successfully determine the most efficient and effective location for placing a harmonic filter bank based upon the desired objectives. The two harmonic current injection scenarios serve to validate the proposed strategy regardless of the power distribution level at which harmonic current is injected. Index Terms—Filtering, harmonic similarity (HS), industrial distribution system, power quality, power-system harmonics.
    IEEE Transactions on Industrial Electronics 01/2012; 59(2):740-751. · 6.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper introduces a quadratic-nonlinearity powers-index spectrum (QNLPI(ƒ)) measure that describes quantitatively how much of the mean square power at certain frequency ƒ is generated by nonlinear quadratic interaction between different frequencies inside signal spectrum. The proposed index QNLPI(ƒ) is based on the bicoherence spectrum, and the index can be simply seen as summary of the information contained in the bicoherence spectrum in two dimensional graph which makes it easier to interpret. The proposed index is studied first using computer generated data and then applied to real-world vibration data from a helicopter drive train to characterize different mechanical faults. This work advances the development of health indicators based on higher order statistics to assess fault conditions in mechanical systems.
    Conference Record - IEEE Instrumentation and Measurement Technology Conference 01/2012;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Accelerometer data has been gathered from accelerated conditioning in grease lubricated and lubrication deprived gear meshes in AH-64 helicopter intermediate and tail rotor gearbox, which are commonly problematic components of the Apache helicopter platform. These tests were performed in a controlled drive-train research test bed, simulating drive-train conditions to improve diagnostic and prognostic capabilities of Condition Based Maintenance (CBM) practices in Integrated Vehicle Health Monitoring System - Health Usage Monitoring System (IVHMS-HUMS) and other comparable CBM packages, as monitored by a standardized Digital Source Collector (DSC) system. Time-frequency representations of vibration measurement collected from two spaced sensors are used to provide signature analysis of transient system harmonics. Furthermore, the time-frequency mutual information advanced signal processing technique is then proposed and validated using vibration data. The measure advances the development of mutual information health indicators to quantify degradation of the helicopter power train. The AH-64 test systems perform under stress in realistic loading conditions and lifetime accelerated aircraft aging is monitored using the proposed advanced signal processing techniques for baseline tests for comparison with faulted conditions.
    Aerospace Conference, 2011 IEEE; 04/2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: Utilities are experiencing premature failures of power cables. In order to prevent electrical outages and to save on repair expenses, a nondestructive and nonintrusive condition assessment technique is highly desirable to evaluate the cable status and to predict the remaining life of a cable. In this paper, the capability of joint time-frequency domain reflectometry (JTFDR) as such a condition assessment technique is studied. The health status of three popular insulations in power system cables - cross-linked polyethylene, ethylene propylene rubber, and silicone rubber - is monitored using the JTFDR in a thermal accelerated aging test. The experimental results show that the JTFDR can successfully monitor the aging process of all three insulations. Then, the results from the JTFDR are compared with the results from the elongation at break (EAB); the results show that the JTFDR technique is comparable with the EAB and has a great potential as a nondestructive and nonintrusive condition assessment technique.
    IEEE Transactions on Instrumentation and Measurement 04/2011; · 1.36 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new concept of nonparametric signal detection and classification technique is proposed using mutual infor- mation measures in the time-frequency domain. The time- frequency-based self-information and mutual information are defined in terms of the cross time-frequency distribution. Based on time-frequency mutual information theory, this paper presents applications of the proposed technique to real-world vibration data obtained from a dedicated condition-based-maintenance experimental test bed. Baseline, unbalanced, and misaligned experimental settings of helicopter drivetrain bearings and shafts are quantitatively distinguished by the proposed techniques. With imbalance quantifiable by variance in the in-phase mutual infor- mation and misalignment quantifiable by variance in the quadra- ture mutual information developed and presented herein, machine health classification can be accomplished by use of statistical bounding regions.
    IEEE Transactions on Instrumentation and Measurement 01/2011; 60:2984-2994. · 1.36 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new methodology for the evaluation of nonfailure operating time (NFOT) in the virtual test bed (VTB) environment is proposed. The proposed method is featured by the application of time-frequency analysis to estimate the parameters of reliability at the earliest stages of design based on the intercoupling of the 1/ f noise and the reliability of power system elements. The proposed approach enables one to directly quantify the reliability of the system by the investigation of the physical properties of the nonequilibrium fluctuations.
    IEEE Transactions on Instrumentation and Measurement 08/2010; · 1.36 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, we propose a high-resolution time-frequency-domain reflectometry technique as a methodology of detection and estimation of faults on a wire. This method adopts the time-frequency cross-correlation characteristics of the observed signal in both the time and frequency domains simultaneously. The accuracy of the proposed method is verified with experiments using a radio-guide-type coaxial cable and comparing it with traditional time-domain as well as frequency-domain reflectometry methods. It is clearly shown here that the proposed algorithm produces excellent results compared to the conventional methods for single as well as multiple fault cables.
    IEEE Transactions on Electromagnetic Compatibility 03/2009; · 1.33 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper develops a signal processing, time-frequency analysis-based analytic solution to locate transient capacitor switching disturbances. The flow of transient disturbance energy caused by the capacitor switching is determined by the time and frequency localized phase difference. Cross time-frequency analysis provides time- and frequency-localized phase difference between the transient voltage and current disturbance waveforms which determine the direction of transient disturbance energy flow. The time and frequency localization properties of the proposed scheme allows one to expand the application to complicated power distribution systems without knowledge of system parameters, capacitor size, and configuration. The proposed scheme has been verified by the electromagnetic transients program simulation for all possible spatial locations of the capacitor switching.
    IEEE Transactions on Power Delivery 11/2008; · 1.52 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In order to maintain the integrity and safe operation of a power system, a state-of-the-art wiring diagnostic technique is imperative. Joint time-frequency domain reflectometry (JTFDR) is proposed as an ideal solution due to its customizable reference signal and unique time-frequency cross-correlation function. The reference signal depends on three parameters: center frequency, bandwidth, and time duration. Previously, these parameters were chosen based on the frequency characteristics of the cable under test. This paper will fully analyze the changing effects of a wide-range of parameter combinations on two different types of defects. It is determined that there exist optimal reference signal parameters for particular defect types. With this knowledge, JTFDR is able to more sensitively detect various defect types over a longer distance than previously possible.
    AUTOTESTCON, 2008 IEEE; 10/2008
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Per-flow congestion control helps endpoints fairly and efficiently share network resources. Better utilization of network resources can be achieved, however, if congestion management algorithms can determine when two different flows share a congested link. Such knowledge can be used to implement cooperative congestion control or improve the overlay topology of a P2P system. Previous techniques to detect shared congestion either assume a common source or destination node, drop-tail queueing, or a single point of congestion. We propose in this paper a novel technique, applicable to any pair of paths on the Internet, without such limitations. Our technique employs a signal processing method, wavelet denoising , to separate queueing delay caused by network congestion from various other delay variations. Our wavelet-based technique is evaluated through both simulations and Internet experiments. We show that, when detecting shared congestion of paths with a common endpoint, our technique provides faster convergence and higher accuracy while using fewer packets than previous techniques, and that it also accurately determines when there is no shared congestion. Furthermore, we show that our technique is robust and accurate for paths without a common endpoint or synchronized clocks; more specifically, it can tolerate a synchronization offset of up to one second between two packet flows.
    IEEE/ACM Transactions on Networking 09/2008; · 2.01 Impact Factor
  • Jingjiang Wang, P. Crapse, Yong-June Shin, R. Dougal
    [Show abstract] [Hide abstract]
    ABSTRACT: Defective cables in the electric power systems of nuclear power plants can cause a component to fail, resulting in potential safety concerns. Due to this problem, a non-destructive, non-intrusive condition assessment technique is highly desirable. Joint time-frequency domain reflectometry (JTFDR) is proposed and verified to be effective for cross-linked polyethylene (XLPE) cable, which serves critical instrumentation and control operations in nuclear power plants. The experimental results demonstrate and verify the ability of JTFDR to effectively detect and locate incipient defects with high accuracy and to monitor the aging process of the cables to predict both future defects and the remaining service life of the cables.
    Electrical Insulation, 2008. ISEI 2008. Conference Record of the 2008 IEEE International Symposium on; 07/2008
  • Source
    Jingjiang Wang, P. Crapse, Yong-June Shin, R. Dougal
    [Show abstract] [Hide abstract]
    ABSTRACT: The integrity of the wiring in the electric power system of a ship is vital to its safe operation. To ensure the wiring integrity, it must be tested to determine if any incipient defects exist. Due to this problem, a non-destructive, non-intrusive condition assessment technique is highly desirable. Joint time-frequency domain reflectometry (JTFDR) is proposed and the theory behind JTFDR is also discussed. The experimental results demonstrate and verify the ability of JTFDR to be effective for polytetrafluoroethylene (PTFE) coaxial cable, which has been widely adopted for military applications in ship power systems. It is shown that JTFDR has the ability to detect and locate incipient defects with high accuracy and monitor the aging process of the cables to predict both future defects and the remaining service life of the cables.
    Instrumentation and Measurement Technology Conference Proceedings, 2008. IMTC 2008. IEEE; 06/2008
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The classical time-frequency distributions represent time- and frequency-localized energy. However, it is not an easy task to analyze multiple signals that have been simultaneously collected. In this paper, a new concept of non-parametric detection and classification of the signals is proposed using the mutual information measures in the time-frequency domain. The time-frequency-based self and mutual information is defined in terms of cross time-frequency distribution. Based on the time-frequency mutual information theory, this paper presents applications of the proposed technique to real-world vibration data. The baseline and misaligned experimental settings are quantitatively distinguished by the proposed technique.
    Proc SPIE 01/2008;
  • [Show abstract] [Hide abstract]
    ABSTRACT: For the proper maintenance of power quality in an electric ship power system, new harmonic metrics are introduced to assess the propagation of disturbances in the system. Classical frequency-based power quality indices are implemented into a harmonic distance metric that measures how much of a disturbance is transmitted from one particular node to another. The harmonic similarity metric is also introduced to provide a measure of how similar two disturbances are based on the magnitudes and phases of their common frequency components. The combination of these metrics leads to the proper assessment of the harmonic configuration of an electric ship power system and to the strategic placement of passive filters to alleviate the effects of harmonic disturbances in the system.
    Electric Ship Technologies Symposium, 2007. ESTS '07. IEEE; 06/2007
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: In this paper, TFDR-based impedance measurement methodology proposed by YongJune Shin et al. (2003) is implemented. TFDR allows one to compensate the error of impedance measurement caused by distortion in transmission line by measuring phase difference and local frequency offset between the input and the reflected signals. The implemented experimental system is composed of the TFDR as a main framework and terminal resistor as load impedance. The experimental results imply that it is possible to acquire more accurate complex impedance with comparatively lower performance instruments than those of the conventional commercial TDR
    Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE; 06/2005
  • Source
    G. Balim, V. Lyashev, V. Popov, Yong-June Shin, R. Dougal
    [Show abstract] [Hide abstract]
    ABSTRACT: A new methodology for the evaluation of non-failure operating time (NFOT) in virtual test bed environment is proposed. The proposed method is featured by the application of signal processing techniques to estimate parameters of reliability at the earliest steps of design based on intercoupling 1/f noise and reliability of power system elements. The proposed approach enables one to directly quantify the reliability of the system by the investigation of the physical properties of the nonequilibrium fluctuation
    Instrumentation and Measurement Technology Conference, 2005. IMTC 2005. Proceedings of the IEEE; 06/2005

Publication Stats

82 Citations
19.17 Total Impact Points

Institutions

  • 2014
    • Yonsei University
      • Department of Electrical and Electronic Engineering
      Sŏul, Seoul, South Korea
  • 2008
    • University of Texas at Austin
      • Department of Electrical & Computer Engineering
      Austin, TX, United States
  • 2005–2008
    • University of South Carolina
      • Department of Electrical Engineering
      Columbia, SC, United States
    • Ryazan State Radio Engineering University
      Riazan, Rjazan, Russia