Josif J. Tomić

Josif J. Tomić


Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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2 January 2021 in Energies
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MKMiodrag Kušljević
Miodrag Kušljević
JTJosif J. Tomić
Josif J. Tomić
Predrag D. PoljakPredrag D. Poljak
Predrag D. Poljak
This article deals with the implementation of the P-Class PMU compliant with IEC/IEEE Standard 60255-118-1:2018 by usage of a multiple-resonator (MR)-based approach for harmonic analysis having been proposed recently. In previously published articles, it has been shown that a trade-off between opposite requirements is possible by shifting a measurement time stamp along the filter window. Positioning the time stamp in a proximity of the time window center assures flat-top frequency responses. In this article, through simulation tests carried out under various conditions, it is shown that requirements of the IEC/IEEE Standard 60255-118-1:2018 can be satisfied by the second and third order MR structure for particular conditions of the time stamp location.

1 January 2015 in Serbian Journal of Electrical Engineering
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DRDejan Reljic
Dejan Reljic
JTJosif J. Tomić
Josif J. Tomić
ZKZeljko Kanovic
Zeljko Kanovic
In this paper, a suitable method for the on-line detection of the airgap mixed eccentricity fault in a three-phase cage induction motor has been proposed. The method is based on a Motor Current Signature Analysis (MCSA) approach, a technique that is often used for an induction motor condition monitoring and fault diagnosis. It is based on the spectral analysis of the stator line current signal and the frequency identification of specific components, which are created as a result of motor faults. The most commonly used method for the current signal spectral analysis is based on the Fast Fourier transform (FFT). However, due to the complexity and memory demands, the FFT algorithm is not always suitable for real-time systems. Instead of the whole spectrum analysis, this paper suggests only the spectral analysis on the expected airgap fault frequencies employing the Goertzel?s algorithm to predict the magnitude of these frequency components. The method is simple and can be implemented in real-time airgap mixed eccentricity monitoring systems without much computational effort. A low-cost data acquisition system, supported by the LabView software, has been used for the hardware and software implementation of the proposed method. The method has been validated by the laboratory experiments on both the line-connected and the inverter-fed three-phase fourpole cage induction motor operated at the rated frequency and under constant load at a few different values. In addition, the results of the proposed method have been verified through the motor?s vibration signal analysis.

30 May 2023 in Acoustics
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MKMiodrag Kušljević
Miodrag Kušljević
VVVladimir Vujicic
Vladimir Vujicic
JTJosif J. Tomić
Josif J. Tomić
Predrag D. PoljakPredrag D. Poljak
Predrag D. Poljak
The use of a filter bank of IIR filters for the spectral decomposition and analysis of signals has been popular for many years. As such, a new filter-bank resonator-based structure, representing an extremely hardware-efficient structure, has received a good deal of attention. Recently, multiple-resonator (MR)-based and general cascaded-resonator (CR)-based filters have been proposed. In comparison to single-resonator-based analyzers, analyzers with a higher multiplicity of resonators in the cascade provide lower side lobes and a higher attenuation in stopbands. In previous works, it was shown that the CR-based filter bank with infinite impulse response (IIR) filters, which is numerically more efficient than one with finite impulse response (FIR) filters, is suitable for dynamic harmonic analysis. This paper uses the same approach to design complex digital filter banks. In the previous case, the optimization task referred to the frequency responses of harmonic filters. In this work, the harmonic filters of the mother filter bank are reshaped so that the frequency response of the sum (or difference, depending on the parity of the number of resonators in the cascade) of two adjacent harmonic filters is optimized. This way, an online adaptive filter base can be obtained. The bandwidth of the filters in the designed filter bank can be simply changed online by adding or omitting the output signals of the corresponding harmonics of the mother filter.

1 August 2021 in Tehnicki vjesnik - Technical Gazette
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MKMiodrag Kušljević
Miodrag Kušljević
JTJosif J. Tomić
Josif J. Tomić
Predrag D. PoljakPredrag D. Poljak
Predrag D. Poljak
Recently, a multiple-resonator structure was proposed as a robust and computationally efficient tool for harmonic analysis. Two trivial cases have been previously observed. The first case exhibits good out-of-band suppression and...

19 March 2021 in IEEE Transactions on Instrumentation and Measurement
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Journal Article
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MKMiodrag Kušljević
Miodrag Kušljević
JTJosif J. Tomić
Josif J. Tomić
Predrag D. PoljakPredrag D. Poljak
Predrag D. Poljak
In the above article [1] , the following expressions were published incorrectly. The correct expressions are given as follows.