An Electrical Impedance Tomography System for Brain Stroke Imaging based on a Lebesgue-Space Inversion Procedure
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In particular, a time-difference formulation is adopted, and the resulting ill-posed equation is solved by means of an iterative procedure performing a regularization in the framework of Lebesgue spaces. The performance of the method has been assessed by means of several numerical simulations. Moreover, a preliminary validation with experimental data has been performed, too. The obtained results confirm that the approach is able to effectively detect inclusions with different sizes and locations inside the considered head models.
Review of Self-Injection-Locked Radar Systems for Noncontact Detection of Vital Signs
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Several approaches to detecting vital sign signals and locations using SIL radar systems have been proposed. This paper summarizes developments in vital sign detection and localization. Finally, some results of detecting animals using SIL radar systems are presented.
Stroke Classification in Simulated Electromagnetic Imaging Using Graph Approaches
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A total of 50 ICH and 50 IS signals simulated using a 16-antenna electromagnetic head imaging system are analysed to evaluate GDMI. The data collected from each model consists of 256 reflected and received signal. Subsequently, noise is injected into the collected signals to generate three groups of signals with different signal-to-noise ratios (40~dB, 25~dB and 10~dB SNR), to emulate measurement noise and to test the algorithm’s robustness}. Each signal is converted into a graph to avoid the variable signal amplitudes. Then, the relationship between each pair of graph degrees is calculated by mutual information and forwarded to a support vector machine to identify stroke type. The results indicate that signals from ICH subjects exhibit a significantly higher GDMI compared to the IS group (p<0.01). An accuracy of 88% is achieved in identifying ICH from IS without the need to use time- and resource-expensive brain image reconstruction algorithms even under 25~dB signal-to-noise levels. The execution time for graph feature extraction and classification is less than one minute on a PC. Such a short time is suitable for stroke emergency requirements.
A Multifunction Dense Array System with Reconfigurable Depth of Penetration
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Additional functions are also being studied; tunable excitation field patterning, reconfigurable depth of penetration, multiple excitation sites, power efficient waveforms and reduced extraneous excitation. Multichannel, multi-coil arrays show promise in achieving many of these parameters in one multifunctional array as opposed to the single-function commercial coils (circular, figure-8 or H coil) being used today. As such, our central focus is to determine whether multifunction dense arrays, despite their many challenges, are a tractable technical approach for future neuromodulation systems. Therefore, the results in this paper are twofold. First, we report the design, fabrication and demonstration of a scalable multichannel (12 channels) or multifunction dense array system to assess the potential to perform these functions in one system. Second, we demonstrate that the depth of penetration of the magnetic field can be reconfigured by varying current magnitude and phase of the smaller coil diameters in the array to achieve the same decay profile performance of a larger diameter coil. Only simulations exist in the literature to date, to the best of our knowledge, we report the first measurements of hexagonal shaped coils in multi-coil arrays have increased depth of penetration over circular shaped coil-based arrays.
A Wireless Wearable RF Sensor for Brumation Study of Chelonians
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In contrast, our sensor on harness can couple significant RF energy into various body parts to evaluate the heartbeat, respiration and activity levels. The self-contained unit is lightweight for ease of wearable deployment and low power to avoid unnecessary heat generation as well as frequent battery replacement. We recorded the shell temperature, heart rate, respiration rate and activity levels of a Russian tortoise during the entire brumation cycle and found that the heart rate correlated with the ambient temperature well, while the breath rate did not significantly reduce during brumation. This experimental study is minimally invasive and thus least biased.
Broadband Implantable Antenna for Wireless Power Transfer in Cardiac Pacemaker Applications
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Additionally, a new wireless power transfer (WPT) system is designed by integrating with a miniaturized metasurface to enhance the WPT efficiency and extend the lifetime of the implantable device. The transmission coefficient S21 of the WPT system loaded with metasurface is 11 dB higher than the initial system at the resonance point. Furthermore, biosafety is taken into consideration for practical applications. The experiments in the equivalent body environment are performed to demonstrate the reliability of the proposed antenna. The measured and simulated results are in good agreement, which shows that the proposed antenna is appropriate to be applied in wireless body area network communication and power transfer systems simultaneously.
