29 research outputs found

    Two-dimensional Forward-Backward Time-Stepping approach for tumor detection in dispersive breast tissues

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    The Forward-Backward Time-Stepping (FBTS) technique is applied to determine the presence and location of malignant tumor in the heterogeneous breast model. A new strategy is integrated in the FBTS algorithm to accurately estimate the dielectric properties of tissues. We demonstrate 2-D FBTS technique utilizing the numerical dispersive breast model in a free space. This new strategy manipulating Debye dispersion equation is proposed to treat dispersive case. Numerical simulation results show the FBTS algorithm has the potential to provide useful quantitative information of the breast\u27s internal composition.2009 Mediterranean Microwave Symposium (MMS) : Tangiers, Morocco, 2009.11.15-2009.11.1

    Microwave breast imaging by the filtered forward-backward time-stepping method

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    In this paper, an inverse scattering technique referred to as the filtered forward-backward time-stepping method is applied to microwave imaging for breast cancer detection. A two-dimensional numerical breast phantom (derived from MR images) with high contrast between fat and fibroglandular tissues, and low contrast between fibroglandular and tumor tissues are used to assess the efficacy of the proposed method.2010 URSI International Symposium on Electromagnetic Theory (EMTS 2010) : Berlin, Germany, 2010.08.16-2010.08.1

    B2-Spline Interpolation Technique for Overset Grid Generation and Finite-Diļ¬€erence Time-Domain Method

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    ā€”In this paper, B2-spline interpolation technique for Overset Grid Generation and FiniteDiļ¬€erence Time-Domain (OGG-FDTD) method was developed. B2-spline or biquadratic spline interpolation oļ¬€ers better accuracy than bilinear interpolation. Two-dimensional (2D) numerical simulations were carried out for electromagnetic (EM) ļ¬eld analysis to measure the scattered ļ¬elds for an unknown object in free space and dielectric medium. In this work, two antennas were utilised as transmitter and receiver sequentially to transmit microwave pulses and collect the scattered ļ¬elds for an unknown object in OGG-FDTD lattice. In order to analyse the stability and eļ¬ƒciency of the proposed method, the scattered ļ¬elds for the unknown object were investigated with error analysis. The results showed that the OGG-FDTD method with B2-spline interpolation gave lower relative error than bilinear interpolation with 0.0009% of diļ¬€erence in free space, 0.0033% of diļ¬€erence in Case A dielectric medium, 0.236% of diļ¬€erence in Case B dielectric medium, and 0.003% of diļ¬€erence in Case C dielectric medium. Besides, the Mean Square Error (MSE) for the OGG-FDTD method with B2-spline interpolation was also lower than the bilinear interpolation. Hence, it proves that the OGG-FDTD method with B2-spline interpolation has the ability to measure the scattered ļ¬elds around an unknown object accurately. For future work, the proposed method can be applied to inverse scattering to detect and reconstruct buried objects with arbitrary shapes in a complex media

    Electromagnetic Field Scattering of a High Speed Moving Source and Its Application

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    This paper presents the electromagnetic (EM) field scattering of a high speed moving source and a moving target by using Finite-Difference Time-Domain (FDTD) with Overset Grid Generation (OGG) method. The analysis is conducted for 750MHz band at the street intersection with OpenMP parallel processing technique. The performance of this proposed method is verified with theoretical results. The simulation results have shown comparatively good agreement in moving and stationary case. The proposed simulation study is of great importance to ground transportation in Intelligent Transportation System (ITS) applications

    Advances in the 3-D forward-backward time-stepping (FBTS) inverse scattering technique for breast cancer detection.

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    This paper presents recent advances in a 3-D inverse scattering technique, called forward-backward time-stepping (FBTS), applied to the reconstruction of the microwave properties of the breast. The FBTS algorithm is utilized for a numerical-based study of a 3-D breast model based on an MRI. Several illumination schemes, based on different microwave transmitter/receiver configurations, are compared based on the quality of the reconstructed images of the breast model. A combination of cylindrical and planar arrays is shown to provide accurate estimates of the model electrical parameters that delineate the various regions of the breast. Although further analysis with this combination array demonstrates that tumors of reduced size and reduced contrast with the surrounding fibroglandular region are much more difficult (and in some cases not possible) to reconstruct, the study presents some promising initial results of a reconstruction technique for breast imaging and cancer detection

    A review on recent available positioning technologies and its advancement

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    This paper reviews and compares the available positioning technology for location based application such as the Intelligent Transport System (ITS) and personal vehicle positioning. With the rapid growing trend of worldwide vehicle ownership, issues such as traffic congestion, environmental pollution, energy consumption and road accident cases are increasing. Intelligent Transportation System (ITS) which depends on location and positioning has been identified as one of the advocated key to resolve the issues. Global Positioning System (GPS) is one of the most promising ubiquitous positioning technologies accepted worldwide for ITS application. It is discerned that GPS alone in ITS application is not adequate since GPS faced Non-Line-of-Sight (NLOS) and multipath effect. New technology integrated is needed to overcome the drawback of the current system for continuous positioning; particularly important for ITS application to be fully functional. This is the significant motivation for tremendous research works had been carried out to improve the performance of positioning. In this paper, advantages and disadvantages of the recent available positioning technologies being used in the implementation of ITS such as satellite-based positioning, network-based positioning and location integration of several positioning technologies is found to be able to improve accuracy, reliability, availability and applicability of the ITS

    A Review of a Single Neuron Weight Optimization Model for Adaptive Beam Forming

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    In this paper, we review our recent, reported work on using artificial intelligence based software technique to control electronic sensor or wireless communication equipment in narrow and diverging paths such as in underground tunnels and at traffic junctions. In order to make the systems fast as well as needing minimal computational calculations and memory ā€“ thus to extend the battery life and minimize cost ā€“ we used the single layer Perceptron to successfully accomplish the formation of beams which may be changed according to the nature of the junctions and diverging paths the mobile or stationary system is to handle. Moreover, the beams that survey the scenario around (e.g. in case of guiding a driverless vehicle) or communicating along tunnels (e.g. underground mines) need to be kept narrow and focused to avoid reflections from buildings or rough surfaced walls which will tend to significantly degrade the reliability and accuracy of the sensor or communicator. These requirements were successfully achieved by the artificial intelligence system we developed and tested on software, awaiting prototype development in the near future

    Integrated Open Loop Resonator Filter Designed with Notch Patch Antenna for Microwave Applications

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    This paper presented the design of integrated open loop resonator bandpass filter with notch type antenna for the use in microwave applications. Chebyshev type filter is selected as the filter characteristics and cascaded design with the antenna to produce a single module, Integrated Filter Antenna (IFA). Special feature of the antenna is the implementation of notch on the patch antenna to improve the efficiency. IFA is then simulated in electromagnetic simulation tool, Agilent Advance Design System (ADS) version 2016 and measured using R&S Vector Network Analyzer. It shows that the proposed IFA produced good measured return loss >-30dB with both vertical and horizontal gain of 9.11dBi and 8.01dBi respectively
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