In its simplest shape, the pseudosinusoidal signal given by an arbitrary wave form generator is constituted by a continuation of samples which involve the presence of parasitic harmonics and an increase in its total harmonic distortion (THD) value. It seems evident that the signal shape can be improved by using a linear interpolation between two consecutive samples but, to our knowledge, this improvement is not evaluated quantitatively to date. So, we propose to calculate this THD (according to the number of samples used to build the signal) with or without linear interpolation. SPICE simulations and experimental results agree with theory.
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http://dx.doi.org/10.1063/1.2437162 | DOI Listing |
We present a wideband rectifying metasurface (RMS) with enhanced system efficiency for wireless power transmission and energy harvesting. The RMS consists of periodic arrays with integrated diodes, with a high input impedance matched with the diodes, thus eliminating the matching network between metasurface (MS) and rectifier. Besides, a unique harmonic feedback network is embedded in each unit cell, rectifying the high-order harmonic generated by the diode repeatedly, improving the total efficiency over a wide bandwidth.
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January 2025
School of ECE, Adama Science and Technology University, Adama, Ethiopia.
This paper details the hardware implementation of a Universal Converter controlled by an Artificial Neural Network (ANN), utilizing key components such as six Insulated Gate Bipolar Transistors (IGBTs), two inductors, and two capacitors for energy storage and voltage smoothing. A Digital Signal Processor (DSP) serves as the core controller, processing real-time input and feedback signals, including voltage and current measurements, to dynamically manage five operational modes: rectifier buck, inverter boost, DC-DC buck, DC-DC boost, and AC voltage control. The pre-trained ANN algorithm generates pulse-width modulation (PWM) signals to control the switching of the IGBTs, optimizing timing and duty cycles for efficient operation.
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January 2025
Department of Electrical Engineering, College of Engineering, King Khalid University, P.O. Box 394, Abha, 61421, KSA, Saudi Arabia.
In wind energy generation systems, ensuring high energy quality is critical but is often compromised due to the limited performance and durability of conventional regulators. To address this, this work presents a novel controller for managing the machine-side inverter of a single-rotor large wind turbine system using an induction machine-type generator. The proposed controller is designed using proportional, integral, and derivative error-based mechanisms, which fundamentally differ from traditional proportional-integral (PI) regulators.
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December 2024
Neuromodulation Center and Center for Clinical Research Learning, Spaulding Rehabilitation Hospital, Massachusetts General Hospital, Harvard Medical School, 1575 Cambridge Street, Cambridge, MA 02115, USA.
Background: This study aimed to explore the potential associations between voice metrics of patients with PD and their motor symptoms.
Methods: Motor and vocal data including the Unified Parkinson's Disease Rating Scale part III (UPDRS-III), Harmonic-Noise Ratio (HNR), jitter, shimmer, and smoothed cepstral peak prominence (CPPS) were analyzed through exploratory correlations followed by univariate linear regression analyses. We employed these four voice metrics as independent variables and the total and sub-scores of the UPDRS-III as dependent variables.
Materials (Basel)
January 2025
Department of Architecture and Civil Engineering, City University of Hong Kong, Hong Kong.
This paper investigates the effects of particle morphology (PM) and particle size distribution (PSD) on the micro-macro mechanical behaviours of granular soils through a novel X-ray micro-computed tomography (μCT)-based discrete element method (DEM) technique. This technique contains the grain-scale property extraction by the X-ray μCT, DEM parameter calibration by the one-to-one mapping technique, and the massive derivative DEM simulations. In total, 25 DEM samples were generated with a consideration of six PSDs and four PMs.
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