Automated Condition-Based Suppression of the CPR Artifact in ECG Data to Make a Reliable Shock Decision for AEDs during CPR

Cardiopulmonary resuscitation (CPR) corrupts the morphology of the electrocardiogram (ECG) signal, resulting in an inaccurate automated external defibrillator (AED) rhythm analysis. Consequently, most current AEDs prohibit CPR during the rhythm analysis period, thereby decreasing the survival rate. To overcome this limitation, we designed a condition-based filtering algorithm that consists of three stop-band filters which are turned either ‘on’ or ‘off’ depending on the ECG’s spectral characteristics. Typically, removing the artifact’s higher frequency peaks in addition to the highest frequency peak eliminates most of the ECG’s morphological disturbance on the non-shockable rhythms. However, the shockable rhythms usually have dynamics in the frequency range of (3–6) Hz, which in certain cases coincide with CPR compression’s harmonic frequencies, hence, removing them may lead to destruction of the shockable signal’s dynamics. The proposed algorithm achieves CPR artifact removal without compromising the integrity of the shockable rhythm by considering three different spectral factors. The dataset from the PhysioNet archive was used to develop this condition-based approach. To quantify the performance of the approach on a separate dataset, three performance metrics were computed: the correlation coefficient, signal-to-noise ratio (SNR), and accuracy of Defibtech’s shock decision algorithm. This dataset, containing 14 s ECG segments of different types of rhythms from 458 subjects, belongs to Defibtech commercial AED’s validation set. The CPR artifact data from 52 different resuscitators were added to artifact-free ECG data to create 23,816 CPR-contaminated data segments. From this, 82% of the filtered shockable and 70% of the filtered non-shockable ECG data were highly correlated (>0.7) with the artifact-free ECG; this value was only 13 and 12% for CPR-contaminated shockable and non-shockable, respectively, without our filtering approach. The SNR improvement was 4.5 ± 2.5 dB, averaging over the entire dataset. Defibtech’s rhythm analysis algorithm was applied to the filtered data. We found a sensitivity improvement from 67.7 to 91.3% and 62.7 to 78% for VF and rapid VT, respectively, and specificity improved from 96.2 to 96.5% and 91.5 to 92.7% for normal sinus rhythm (NSR) and other non-shockables, respectively.

Compact, Reflectionless Band-Pass Filter: Based on GaAs IPD Process for Highly Reliable Communication

For highly reliable and compact communication of front-end modules, a miniaturized reflectionless band-pass filter, based on the GaAs integrated passive device (IPD) process, is proposed in this work. The stop-band signal absorption rate of the filter can reach more than 90% and greatly reduce the influence of electromagnetic interference for sensitive devices. First, a circuit topology of reflectionless filter is proposed. Then, the miniaturized reflectionless band-pass filter is designed and fabricated based on GaAs IPD process with a compact size of only 0.85 mm × 1.33 mm × 0.09 mm (0.011λ × 0.018λ × 0.001λ). The filter operates at frequency ranging from 3.3 GHz to 4.5 GHz for 5G communication, the insertion loss (S21) is less than 3 dB, the return loss in the passband (S11) is over 15 dB, the stopband return loss (S11) is over 10 dB, and the out-of-band suppression (S21) reached 19 dB. All the measured results are in good agreement with the simulated results. It shows great potential in the process of designing highly reliable and compact monolithic integrated wireless modules and wearable electronics.

Potential Use of Cold Plasma Discharges for Frequency Reconfigurability in a Sievenpiper Mushroom Metasurface

This article presents a parametric study using full-wave simulations about the potential use of cold plasma discharges to achieve frequency reconfiguration on a Sievenpiper mushroom metasurface. The study was done by inserting plasma tubes in between the patches of the mushroom structure, in three different positions with respect to the top of the metasurface, and varying the electronic density while keeping the plasma collision frequency. The obtained results show that it is possible to shift the stop-band generated by the metasurface around 25% towards lower frequencies for an electron density value inside the tubes of 1014 cm−3, when they are placed in between the top patches of the metasurface. Additional insertion losses are exhibited when operating near the plasma frequency.

E-Textile Metamaterials: Stop Band Pass Filter

In this paper, the utilization of common fabrics for the manufacturing of e-textile metamaterial is investigated. The proposed design is based on a transmission line loaded with split-ring resonators (SRRs) on a cotton substrate for filter signal application. The proposed design provides a stop band between 2.7 GHz and 4.7 GHz, considering a four stage SRR topology. Experimental results showed stop band levels higher than −30 dB for the proposed compact embroidered metamaterial e-textiles. The validated results confirmed embroidery as a useful technique to obtain customized electromagnetic filter properties, such as transmitted signal filtering and control, on wearable tech device applications.

Bandwidth Control of Loop Type Frequency Selective Surfaces Using Dual Elements in Various Arrangements

Frequency-selective surfaces (FSSs) have applications across multiple disciplines due to their unique electromagnetic properties. This paper investigates the use of both rounded square loops (RSLs), and simple loop type dual elements arranged in unique patterns, to control the transmission and reflection bandwidth and resonant frequencies over KU and K frequency bands supported by equivalent circuit models (ECMs). The FSSs were fabricated using laser engraving to create conductive loop type elements on a thin, flexible and optically transparent Mylar substrate (relative permittivity of 2.7 and thickness of 65m). The frequency response of the surfaces are controlled through the element self-inductance and capacitive coupling with neighbouring elements. This work shows that different arrangements result in the formation of multiple distinct resonances. The theoretical and experimental results were in good agreement where rounded squares and dual element arrays were employed to create broadband and multiband band-stop FSSs. A polarization sensitive surface exhibited stop-bands at 12GHz and 16GHz in transverse electric polarization and a stop-band at 14.4GHz in transverse magnetic polarization. This technique can be applied to any periodic array through careful selection of the individual elements in the array, as well as their arrangement.

Clairvoyant Melon Maturity Detection Enabled by Doctor-Blade-Coated Photonic Crystals

Climacteric fruits are harvested before they are ripened to avoid adverse damages during transport. The unripe fruits can undergo ripening processes associated with rind color changes on exposure to ethanol vapors. Although rind coloration is a common indicator showing fruit maturity, the attribute does not provide reliable assessment of maturity especially for melons. Herein, we report the achievement of sensitive and reversible melon maturity detection using macroporous hydrogel photonic crystals self-assembled by a roll-to-roll compatible doctor-blade-coating technology. The consumption of applied ethanol vapor during melon ripening results in less condensation of ethanol vapor in the pores (250 nm in diameter), leading to a distinct blue-shift of the optical stop band from 572 to 501 nm and an obvious visual colorimetric readout from yellow green to blue. Moreover, the dependence of the color change on Brix value within the melon has also been evaluated in the study.

Numerical Study on Propagative Waves in a Periodically Supported Rail Using Periodic Structure Theory

This paper presents the numerical study on propagative waves in a periodically supported rail below 6000 Hz. A periodic rail model, which considers the effects of both the periodic supports and the rail cross section deformation, has been established based on the periodic structure theory and the finite element method. Two selection approaches are proposed to obtain the concerned dispersion curves from the original calculation results of dispersion relations. The differences between the dispersion curves of different support conditions are studied. The propagative waves corresponding to the dispersion curves are identified by the wave modes. The influences of periodic supports on wave modes in pass bands are revealed. Further, the stop band behaviors are investigated in terms of the bounding frequencies, the standing wave characteristics, and the cross-sectional modes. The results show that eight propagative waves with distinct modes exist in a periodically supported rail below 6000 Hz. The differences between the dispersion curves of periodically and continuously supported rails are not obvious, apart from the stop band behaviors. All the bounding-frequency modes of the stop bands are associated with the standing waves. Two bounding-frequency modes of the same stop band can be regarded as two identical standing waves with the longitudinal translation of the quarter-wavelength, one of which is the so-called pinned-pinned resonance.

Moth Flame Optimization Algorithm for Optimal FIR Filter Design

This paper presents the application of Moth Flame optimization (MFO) algorithm to determine the best impulse response coefficients of FIR low pass, high pass, band pass and band stop filters. MFO was inspired by observing the navigation strategy of moths in nature called transverse orientation composed of three mathematical submodels. The performance of the proposed technique was compared to those of other well-known high performing optimization techniques like techniques like Particle Swarm Optimization (PSO), Novel Particle Swarm Optimization (NPSO), Improved Novel Particle Swarm Optimization (INPSO), Genetic Algorithm (GA), Parks and McClellan (PM) Algorithm. The performances of the MFO based designed optimized FIR filters have proved to be superior as compared to those obtained by PSO, NPSO, INPSO, GA, and PM Algorithm. Simulation results indicated that the maximum stop band ripples 0.057326, transition width 0.079 and fitness value 1.3682 obtained by MFO is better than that of PSO, NPSO, INPSO, GA, and PM Algorithms. The value of stop band ripples indicated the ripples or fluctuations obtained at the range which signals are attenuated is very low. The reduced value of transition width is the rate at which a signal changes from either stop band to pass band of a filter or vice versa is very good. Also, small fitness value in an indication that the values of the control variable of MFO are very near to its optimum solutions. The proposed design technique in this work generates excellent solution with high computational efficiency. This shows that MFO algorithm is an outstanding technique for FIR filter design.