Parkinson’s Disease (PD) is a complex neurodegenerative disorder characterized by a spectrum of motor and non-motor symptoms, prominently featuring the freezing of gait (FOG), which significantly ...impairs patients’ quality of life. Despite extensive research, the precise mechanisms underlying FOG remain elusive, posing challenges for effective management and treatment. This paper presents a comprehensive meta-analysis of FOG prediction and detection methodologies, with a focus on the integration of wearable sensor technology and machine learning (ML) approaches. Through an exhaustive review of the literature, this study identifies key trends, datasets, preprocessing techniques, feature extraction methods, evaluation metrics, and comparative analyses between ML and non-ML approaches. The analysis also explores the utilization of cueing devices. The limited adoption of explainable AI (XAI) approaches in FOG prediction research represents a significant gap. Improving user acceptance and comprehension requires an understanding of the logic underlying algorithm predictions. Current FOG detection and prediction research has a number of limitations, which are identified in the discussion. These include issues with cueing devices, dataset constraints, ethical and privacy concerns, financial and accessibility restrictions, and the requirement for multidisciplinary collaboration. Future research avenues center on refining explainability, expanding and diversifying datasets, adhering to user requirements, and increasing detection and prediction accuracy. The findings contribute to advancing the understanding of FOG and offer valuable guidance for the development of more effective detection and prediction methodologies, ultimately benefiting individuals affected by PD.
In this study, the mutual coupling in multiple-input-multiple-output (MIMO) dielectric resonator antenna (DRA) is reduced by employing closed metallic loops. The loops are wrapped around the adjacent ...edges of the dielectric resonators (DR) where magnetic coupling is significant. The proposed method employs only the conductive metallic strips for mutual coupling reduction and this makes the entire design very simple and compact. The impedance bandwidth varies from 4.73 to 5.1 GHz, covering the Sub-6 GHz 5G band. The realized MIMO DRA has an isolation of 28 dB at the resonant frequency with a measured peak gain at each port of 3.5 dBi and a peak radiation efficiency of 93%. The obtained measured results yield a low correlation coefficient (< 0.05) mostly at the entire band that contribute to diversity gain (<inline-formula> <tex-math notation="LaTeX"> > 9.8 </tex-math></inline-formula> dB) to increase the capacity of communication system, is reported in this paper. The proposed antenna was fabricated and the closed loop strip is wrapped around using in house facility. Furthermore, some issues related to the fabrications tolerance have been investigated to justify the difference between some simulated and measured results.
This paper presents a critical review of modern 4G, 4G/5G, and 5G antennas, which employ PIN diodes and Varactors for polarization or frequency reconfiguration. For the reviewed 4G and 5G ...polarization reconfigurable antennas, a new parameter named spectrum utilization "AR/ S 11 B.W." is defined for the first time to predict the shared spectrum between the impedance bandwidth and the axial ratio bandwidth for circularly polarized antennas. The calculated spectrum utilization for many designs revealed that the majority of implementations failed to achieve full utilization of the available bandwidth. Besides, employing multiple PIN diodes is shown useful in improving the spectrum utilization and in supporting multiple polarization states. For the reviewed 4G, 4G/5G and 5G frequency reconfigurable antennas, the focus is mainly on comparing the available tuning range, fractional bandwidth and the Fractional Bandwidth Change (FBWC) upon tuning. The latter parameter, is defined and calculated in this work to measure the change in the FBW upon tuning. Utilizing multiple Varactors is shown promising in improving a 4G antenna's fractional bandwidth, while combining Multiple PINs and Varactors in one design is found efficient in improving the FBWC and the tuning range in the 5G spectrum.
A novel millimeter-wave (MMW) hybrid isolator is presented to reduce the mutual-coupling (MC) between two closely-spaced dielectric resonators (DR) antennas at 60 GHz. The proposed hybrid isolator ...consists of a combination of a new uni-planar compact electromagnetic band-gap (EBG) structure and an MMW choke absorber. The design of the proposed EBG unit-cell is based on the stepped-impedance resonator (SIR) technique. The results show that the proposed EBG structure provides a wide frequency bandgap in the 60 GHz band with miniaturization factors of 0.79 and 0.66 compared to conventional uni-planar EBG and uni-planar compact (UC-EBG) structures, respectively. The proposed EBG is then placed between two Multiple-Input Multiple-Output (MIMO) DR antennas to reduce the MC level. As a result, an average of 7 dB level reduction is obtained. To further reduce the MC level, a thin MMW choke absorber wall is mounted vertically between the two DR antennas and above the EBG structure. An average of 22 dB MC reduction is achieved over the suggested bandwidth while maintaining good radiation characteristics. The measured isolation of the prototype antenna varies from −29 to −49 dB in the frequency range from 59.3 to 64.8 GHz. In fact, the proposed hybrid isolator outperforms other hybrid isolation techniques reported in the literature.
This work presents the design and analysis of newly developed reconfigurable, flexible, inexpensive, optically-controlled, and fully printable chipless Arabic alphabet-based radio frequency ...identification (RFID) tags. The etching of the metallic copper tag strip is performed on a flexible simple thin paper substrate (
= 2.31) backed by a metallic ground plane. The analysis of investigated tags is performed in CST MWS in the frequency range of 1-12 GHz for the determination of the unique signature resonance characteristics of each tag in terms of its back-scattered horizontal and vertical mono-static radar cross section (RCS). The analysis reflects that each tag has its own unique electromagnetic signature (EMS) due to the changing current distribution of metallic resonator. This EMS of each tag could be used for the robust detection and recognition of all realized 28 Arabic alphabet tags. The study also discusses, for the first time, the effect of the change in font type and size of realized tags on their EMS. The robustness and reliability of the obtained EMS of letter tags is confirmed by comparing the RCS results for selective letter tags using FDTD and MoM numerical methods, which shows very good agreement. The proposed tags could be used for smart internet of things (IoT) and product marketing applications.
In this paper, the impact of AlGaN barrier thickness (<inline-formula> <tex-math notation="LaTeX">\text{t}_{\mathrm{ AlGaN}} </tex-math></inline-formula>) and substrate leakage on the noise ...conductance and noise figure in GaN High Electron Mobility Transistor (HEMT) is investigated. The investigation and analysis in this paper are targeting the Low Noise Amplifier (LNA) applications. The noise analysis is carried out using Technology Computer-Aided Design (TCAD) physical simulator. Initially, the DC, RF, and noise simulations are validated against measurements of a GaN device. AlGaN barrier thickness (<inline-formula> <tex-math notation="LaTeX">\text{t}_{\mathrm{ AlGaN}} </tex-math></inline-formula>) is varied and its impact on the minimum noise figure (NFmin) is analyzed. It is observed that the NFmin decreases with <inline-formula> <tex-math notation="LaTeX">\text{t}_{\mathrm{ AlGaN}} </tex-math></inline-formula> reduction at the typical bias conditions of LNA. This observation on the impact of <inline-formula> <tex-math notation="LaTeX">\text{t}_{\mathrm{ AlGaN}} </tex-math></inline-formula> on the NFmin follows Fukui's model, which states that the NFmin decreases with the increase in transconductance. In addition, the impact of the substrate material on noise performance is analyzed. The substrates used for the investigation are Silicon (Si) and Silicon Carbide (SiC). At 40 GHz, it is found that the noise conductance and the NFmin of GaN HEMT on SiC substrate is reduced by 13% and 12%, respectively, in comparison with GaN HEMT on Si substrate. This could be attributed to the lower gate-to-substrate capacitance of the GaN HEMT on SiC substrate.
This paper presents a thorough review of the main techniques used for wireless power transfer (WPT) in implantable medical devices (IMDs) with a specific focus on the techniques that employ ...implantable antennas for energy harvesting (electromagnetic (EM) WPT techniques). The techniques are first analysed and compared based on the IMD application, power transfer efficiency (PTE), transfer distance, implantation depth, implant size, operating frequency, and specific absorption rate (SAR). The study provides a critical analysis of the main WPT system's as well as implantable antennas' design parameters that control the PTE and hence the charging rate of the IMD. The investigated design parameters include the WPT TX-RX antennas' gain, WPT-RX size, transfer distance, and the WPT TX-RX antennas' alignment. Tutorial simulation examples are included to showcase the impact of these design parameters on the amount of power coupled to the IMD. The paper also discusses recent techniques used for improving the amount of power received by implantable antennas, and hence higher PTE and IMDs charging rate, namely, the use of implantable MIMO WPT-RX antennas to mitigate antennas misalignment and the use of metamaterial surfaces to focus the power emitted from WPT-TX antennas towards the implantable WPT-RX antennas. The findings and observations reported in this study serve as a valuable resource for designers and researchers to comprehend the effect of various WPT TX-RX antennas design parameters on PTE. The analysis and full-wave simulation examples, included in the paper, are shown very useful in understanding the challenges associated with WPT in IMDs and in proposing potential solutions.
This paper presents a very compact, wideband, and enhanced-gain antenna for 5G applications. A simple single-layer millimeter wave (mm-wave) metamaterial lens (meta-lens) is used to improve the gain, ...aperture efficiency, and gain bandwidth of a slotted-patch antenna over a wide range of frequencies from 25 GHz to 31 GHz. The lens exhibits a metamaterial negative refractive index behavior, which is attributed to a substantial gain enhancement of around 4-5 dBi over the whole band compared to the gain values of the slotted patch antenna alone. The lens's unit cell comprises a simple single-layer split ring resonator (SRR) whose dimensions are carefully chosen to improve transmitted power and suppress absorbed and reflected power. The meta-lens consists of <inline-formula> <tex-math notation="LaTeX">8\times 8 </tex-math></inline-formula> subwavelength SRR unit cells. Each cell has an area of <inline-formula> <tex-math notation="LaTeX">1.6\times 1.6 </tex-math></inline-formula> mm2, it is located in the near-field region closely above a slotted patch antenna to produce a total antenna size of <inline-formula> <tex-math notation="LaTeX">12.8\times 12.8\times 7.27 </tex-math></inline-formula>mm3 (<inline-formula> <tex-math notation="LaTeX">1.2~\lambda \times 1.2~\lambda \times 0.68~\lambda </tex-math></inline-formula>, where <inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula> is the free space wavelength at 28 GHz). The maximum gain of the proposed antenna is 12.7 dBi, the 1 dB gain bandwidth is 18%, the maximum aperture efficiency is 92%, and the −10 dB impedance bandwidth (10 dB B.W.) is 17%. This excellent combination of essential metrics is hard to realize at mm-wave using narrowband antenna structures (microstrip patch antennas), and the aperture efficiency is the highest thus far for such a class of antennas.
This paper proposes a fully automated vision-based system for real-time COVID-19 personal protective equipment detection and monitoring. Through this paper, we aim to enhance the capability of ...on-edge real-time face mask detection as well as improve social distancing monitoring from real-live digital videos. Using deep neural networks, researchers have developed a state-of-the-art object detector called "You Only Look Once Version Five" (YOLO5). On real images of people wearing COVID19 masks collected from Google Dataset Search, YOLOv5s, the smallest variant of the object detection model, is trained and implemented. It was found that the Yolov5s model is capable of extracting rich features from images and detecting the face mask with a high precision of better than 0.88 mAP_0.5. This model is combined with the Density-Based Spatial Clustering of Applications with Noise method in order to detect patterns in the data to monitor social distances between people. The system is programmed in Python and implemented on the NVIDIA Jetson Xavier board. It achieved a speed of more than 12 frames per second. Doi: 10.28991/ESJ-2023-SPER-05 Full Text: PDF
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