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Electrical and Computer Engineering, Canadian Journal of

Issue 1 • Date Winter 2008

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Displaying Results 1 - 10 of 10
  • Canadian Journal of Electrical and Computer Engineering - Front cover

    Publication Year: 2008
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    Freely Available from IEEE
  • Table of contents

    Publication Year: 2008
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  • Message from the Editors

    Publication Year: 2008
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    Freely Available from IEEE
  • Guest editorial: Special issue on the 2007 IEEE Pacific Rim Conference on Communications, Computers and Signal Processing

    Publication Year: 2008
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    Freely Available from IEEE
  • An improved normal-mesh-based image coder

    Publication Year: 2008 , Page(s): 5 - 14
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1696 KB)  

    The normal-mesh-based image coder of Jansen, Baraniuk, and Lavu (JBL) is studied. First, the JBL coder is introduced, and several of its shortcomings are identified. Then, to address these shortcomings, three modifications to this coder are proposed, namely, the use of a data-dependent base mesh, an integer representation for normal/vertical offsets, and a different scan-conversion scheme based on bicubic interpolation. Experimental results show that these proposed changes lead to improved coding performance in terms of both objective and subjective image-quality measures. In particular, the use of a data-dependent base mesh helps to locate horizons more quickly and preserve image edges better. The number of bits required to encode the normal/vertical offsets is reduced by representing this information with integers (as opposed to real numbers). Lastly, bicubic interpolation is found to yield higher-quality image reconstructions, while still maintaining sharp edges. View full abstract»

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  • Segmentation of medical images using a geometric deformable model and its visualization

    Publication Year: 2008 , Page(s): 15 - 19
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1036 KB)  

    An automatic segmentation method for medical images that uses a geometric deformable model is presented, and the segmented results are visualized with the help of a modified marching cubes algorithm. The geometric deformable model is based on evolution theory and the level set method. In particular, the level set method utilizes a new derived speed function to improve the segmentation performance. This function is defined by the linear combination of three terms, namely, the alignment term, the minimal-variance term, and the smoothing term. The alignment term makes a level set as close as possible to the boundary of an object. The minimal-variance term best separates the interior and exterior of the contour. The smoothing term renders a segmented boundary less sensitive to noise. The use of the proposed speed function can improve the segmentation accuracy while making the boundaries of each object much smoother. Finally, it is demonstrated that the design of the speed function plays an important role in the reliable segmentation of synthetic and computed tomography (CT) images, and the segmented results are visualized effectively with the help of a modified marching cubes algorithm. View full abstract»

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  • Hardware acceleration for similarity computations of feature vectors

    Publication Year: 2008 , Page(s): 21 - 30
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (881 KB)  

    In Web mining applications, an enormous amount of data needs to be processed quickly and efficiently. Thus, hardware support is crucial to enhance the performance of these operations. In this work, chip-level hardware support for similarity measure calculation is introduced and then extended to similarity matrix computation. Both software and hardware versions of various similarity computations are implemented with a hierarchical platform-based design approach to facilitate component reuse at different levels of abstraction. Software modules are executed on a reconfigurable soft processor core on the same field-programmable gate array (FPGA) as the hardware implementations for the purpose of performance comparison. Preliminary results using parallel hardware are also presented. In addition, performance gain from hardware as opposed to a general-purpose processor is examined. Experimental results show that the performance of similarity computation for a set of feature vectors could be significantly enhanced by using on-chip hardware. View full abstract»

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  • High-level FSMD design and automated clock gating with CoDeL

    Publication Year: 2008 , Page(s): 31 - 38
    Cited by:  Papers (1)
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    A high-level VLSI design platform, called CoDeL, which allows hardware description at the algorithm level and thus dramatically reduces design time, is presented. It now directly supports the use of fixed-point operations to ease description of digital signal processing (DSP) algorithms. Also, to dramatically reduce dynamic power dissipation in the resulting architecture, it automatically inserts clock gating for registers at the behavioural level. This is believed to be the first hardware design environment that allows an algorithmic description of a component and yet produces a power-aware design. The DSP stone benchmark is used to thoroughly evaluate this fixed-point design platform for the design of power-efficient DSP architectures. Power analysis is used to compare the effectiveness of CoDeL's automated clock gating to automated clock gating using Synopsys tools. The results show that a combination of CoDeL and Synopsys clock gating provides 16% more power savings, on average, than Synopsys' automated clock gating alone. Finally, the CoDeL platform is compared to a modern DSP processor, and it is found that the CoDeL platform produces designs with somewhat slower run times, but dramatically lower power dissipation. View full abstract»

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  • A turbo SDMA receiver for strongly nonlinearly distorted MC-CDMA signals

    Publication Year: 2008 , Page(s): 39 - 44
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (683 KB)  

    This paper considers the use of space division multiple access (SDMA) techniques for the uplink of multi-carrier code division multiple access (MCCDMA) systems, where the transmitted signals face strong nonlinear distortion effects. The signal transmitted by each mobile terminal (MT) is submitted to a nonlinear operation consisting of a clipping device followed by a frequency-domain filtering operation, so as to reduce the envelope fluctuations and peak-to-mean envelope power ratio (PMEPR) while maintaining the spectral occupation of conventional MC-CDMA signals. At the base station, an iterative receiver employing multiple antennas jointly performs turbo multi-user detection and the estimation and cancellation of nonlinear distortion effects. Performance results show that the proposed receiver structures can achieve good performances that are very close to those obtained with linear transmitters, even for high system load and/or when a very low-PMEPR MC-CDMA transmission is intended for each MT. View full abstract»

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  • A novel complementary sequence and PMEPR reduction in OFDM

    Publication Year: 2008 , Page(s): 45 - 51
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (382 KB)  

    This paper introduces a novel sequence called the "beta-complementary sequence" to encode orthogonal frequency-division multiplexing (OFDM) signals, with which one can substantially increase the code rate while maintaining a tight peak-to-mean envelope power ratio (PMEPR) of at most 2. Moreover, encoding schemes based on beta-complementary sequences provide very good tradeoff performance between PMEPR and code rate. This observation follows from an intrinsic property of the beta-complementary sequences considered. Furthermore, the distribution of code rate versus beta is determined, and numerical results based on these properties are presented. Finally, comparisons with the well-known Golay complementary sequences and the generalized Golay complementary sequences (called "GN-complementary sequences" in this paper) are made. 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.

Full Aims & Scope

Meet Our Editors

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