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Electrical and Computer Engineering, Canadian Journal of

Issue 1 • Date Winter 2010

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Displaying Results 1 - 8 of 8
  • Canadian Journal of Electrical and Computer Engineering - Front cover

    Publication Year: 2010 , Page(s): c1 - c4
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    Freely Available from IEEE
  • Table of contents

    Publication Year: 2010 , Page(s): 1
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    Freely Available from IEEE
  • Time-frequency single-phase power components measurements for harmonics and inter-harmonics distortion based on Wavelet Packet transform;Part I: Mathematical formulation

    Publication Year: 2010 , Page(s): 1 - 7
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (281 KB)  

    This paper represents the first part of a two-part study focusing on power components measurement in the time-frequency domain using Wavelet Packet Transform (WPT). The recommended power components that are contained in the IEEE Standard 1459-2010 are derived based on the Fourier transform approach, which produces inaccurate results in the case of interharmonic distortion. On the other hand, the 'in-phase quadrature' approach that is defined in the time-domain can provide accurate values only for the total active power, total non-active power and total apparent power, while the remaining power components in this standard cannot be evaluated using this approach. This paper proposes redefining the recommended power components in using the 'in-phase quadrature' approach in the time-frequency domain using WPT. This allows the evaluation of the all the recommended power components in both time and frequency domains while providing more accurate results than Fourier transform based approach, especially in case of inter-harmonic distortion. Moreover, defining those power components in the time-frequency domain provides a complete time-frequency picture for these components. This can be useful for many power system applications such as real-time monitoring of active and residual currents at each frequency, selective switching of harmonic, inter-harmonic elimination, instantaneous non-active power compensation and power quality evaluation. View full abstract»

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  • Time-frequency single-phase power components measurements for harmonics and inter-harmonics distortion based on wavelet packet transform; Part II: case studies and results

    Publication Year: 2010 , Page(s): 8 - 14
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (324 KB)  

    This is the second part of a two-part study concerning power components measurement in the time-frequency domain using Wavelet Packet Transform (WPT). Four case studies are presented comparing the recommended power components that are contained in the IEEE Standard 1459-2010 [1] based on Fourier Transform approach, versus power components suggested by the newly developed time-frequency 'in-phase quadrature' approach using Wavelet Packet Transform; the latter derived in the first part of this two-part study. The first two cases are simulated cases in the Matlab environment to include both harmonic and interharmonic distortion, while the other two cases are real data cases acquired from computer loads and Adjustable Speed Drives. The values of the recommended power components using both approaches are compared and the results indicate that the time-frequency 'in-phase quadrature' approach using WPT is more accurate, especially in the presence of interharmonics. Both time and frequency information is preserved, allowing representation of the power components in a time-frequency spectrum. This provides a complete performance picture compatible with present practical load configurations. View full abstract»

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  • A global optimization technique for microwave imaging of the inhomogeneous and dispersive breast

    Publication Year: 2010 , Page(s): 15 - 24
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    This paper illustrates how breast tissue composition, modeled by different mixtures of adipose and glandular tissues, affects the accuracy of microwave breast imaging for different sizes of malignant lesions. To study this, the scattered field for different tissue composition and various tumour sizes was calculated using a Frequency Dependent Finite Difference Time Domain ((FD)2TD) approach. Images are generated from the scattered field, together with Genetic Algorithm (GA) optimization methods. The scattered field calculations show that it is strongly dependent not only on the dielectric properties and size of the breast tissue, but also on the specific tissue composition. The tumour response is the difference between scattered fields of a specific tissue composition with and without the tumour. The response of a 1.5cm tumour was found to be 6.7 times larger when it is embedded within homogeneously uniform fatty tissue than when embedded within homogeneously uniform fibro-glandular tissue. For a tumour inside a heterogeneously dense breast consisting of a mix of fi bro-glandular and fatty tissues, this value is 5.2. The consequences of the biological heterogeneity on the forward and inverse simulation, and on the accuracy of images obtained by microwave imaging using the proposed method were studied. The robustness of our approach to variations in the breast phantom was shown. This technique returned highly accurate results with millimetre resolution. The most rigorous test to date demonstrated that we are able to accurately reconstruct an image of the dielectric properties of a 7.5mm lesion embedded in fibro-glandular tissue at a depth of 6cm in a heterogeneous numerical breast phantom. View full abstract»

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  • Fast block motion estimation based on sorting of prediction vectors

    Publication Year: 2010 , Page(s): 25 - 32
    Cited by:  Papers (2)
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    In this paper we present a new fast motion estimation technique using spatial and temporal correlation among motion vectors. The motion vector of a block can be predicted from the motion vectors of its neighbouring blocks. Statistical analyses show that the role of different neighbouring blocks in the prediction process changes with time. A dynamic sorting routine is offered to let the suggested algorithm use the motion vectors of neighbouring blocks that are more likely to help the search procedure. By using these motion vectors a search centre is located, around which a search window is placed. The size of the search area is dependent on the number of prediction vectors that are used. We try to design an algorithm that can easily be implemented in hardware. Simulation results show that the proposed algorithm, while being simpler than many fast motion estimation algorithms, has compatible or superior performance trajectory. View full abstract»

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  • Separation of core losses in distribution transformers using experimental methods

    Publication Year: 2010 , Page(s): 33 - 39
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (530 KB)  

    The separation of eddy current and hysteresis losses in transformer cores is obtained using the two-temperatures and the two-frequency methods. Loss calculations for six ratings using the voltage test waveform ratio are included to compare and analyze results. A brief description of the test methodologies, that are easy to apply, is given. An example of the application of the methodologies, the obtained measurements and obtained results are included. In some cases, the results show that eddy current losses for the analyzed ratings are greater than 60% of no-load losses. Results include the impact of no-load losses in total owning cost of transformers. View full abstract»

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  • A photonic crystal technology compatible with integrated circuit technologies

    Publication Year: 2010 , Page(s): 40 - 45
    Cited by:  Papers (2)
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    Amorphous silicon oxy-nitride (a-SixOyN1-x-y) films with refractive indices in a wide range of 1.43-1.75 were obtained by plasma-enhanced chemical vapour deposition of silane, nitrous oxide, and ammonia gases at 30°C. Photonic crystal slabs based on a-SixOyN1-x-y material systems were simulated and fabricated. Low-contrast photonic crystal structures for which the refractive index difference between the cladding and the core is small are implemented using this technology. It is shown that even low-contrast photonic crystals can provide fairly wide bandgap. The films were patterned by electron-beam lithography and etched by reactive ion etching. The device fabrication is carried out at low temperature and is independent of the substrate type. Therefore, this technology can be used to integrate photonic crystal-based optical integrated circuits within silicon- and GaAs-based integrated circuits. View full abstract»

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Aims & Scope

The role of the Canadian Journal of Electrical and Computer Engineering is to provide scientific and professional activity for its members in Canada, the CJECE complements international journals and will be of particular interest to anyone involved in research and development activities in the field of electrical and computer engineering.

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Meet Our Editors

Editor-in-Chief
Dr. Shahram Yousefi
Dept. of Electrical and Computer
     Engineering
Queen's University