Miracle-dz/UniFAR-FTUs huggingface dataset:
Miniaturized RFID Reader Antennas Based on CRLH Negative Order Resonance

This article presents a type of miniaturized high-efficiency patch antennas for UHF radio frequency identification (RFID) reader applications based on the composite right-/left-handed (CRLH) negative order resonance. Miniaturization is achieved by using the first negative order resonance (−1st mode). These proposed CRLH resonators are realized by etching gap on the patch surface, which acts as a series left-handed (LH) capacitor as well as an effective radiator, and using metallic screws on the corner as steadying posts while also providing an LH inductor. Different from the traditional mushroom structures, these screws are placed on the two sides or corner of the unit cells allowing unobstructed current and field flowing inside the cavity. This enhances the quality factor and radiation efficiency. In addition, only metallic sheets, screws, and one thin substrate are used in the design, therefore dielectric loss is basically eliminated. Overall, these proposed antennas achieve a miniaturized size, as well as a high gain and radiation efficiency. The radiation characteristics of these RFID antennas are similar to the conventional patch antennas due to the −1st-order operation. Four antennas, including linearly polarized, circularly polarized (CP), frequency-tunable, and polarization/frequency-reconfigurable antennas, are carefully designed, investigated, and experimentally verified. Remarkable agreement has been observed between simulation and measurement. These antennas well cover 902–928 MHz UHF band. RF range tests are carried out for application verification. They demonstrate a compact size, low-cost, low-loss, and high efficiency with easy implementation. The CP antennas exhibit a good bandwidth and an excellent axial ratio in the whole upper semisphere. They have been selected for mass production, which illustrates a good engineering application example of CRLH metamaterial antennas.
A Low-Profile Wideband Hybrid Metasurface Antenna Array for 5G and WiFi Systems

A hybrid metasurface (HMS) is proposed to form a low-profile wideband antenna array. The antenna element is an array of <inline-formula> <tex-math notation="LaTeX">$4\,\,\times4$ </tex-math></inline-formula> square metal patches and fed by a <inline-formula> <tex-math notation="LaTeX">$50~\Omega $ </tex-math></inline-formula> microstrip line through an H-shaped coupling slot on the ground plane. Only are the edge patches of HMS antenna element grounded by shorting pins for the suppression of surface waves and cross-polarization levels as well as the enhancement of the gain. With the HMS antenna element, a compact <inline-formula> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> array with an overall size of <inline-formula> <tex-math notation="LaTeX">$1.58\lambda _{0} \times 1.58\lambda _{0} \times 0.068\lambda _{0}$ </tex-math></inline-formula> (<inline-formula> <tex-math notation="LaTeX">$\lambda _{0}$ </tex-math></inline-formula> is the free-space wavelength at 5.0 GHz) is designed, where the adjacent elements share the edge patches of the elements. The measurement shows the impedance bandwidth of 28% (4.41–5.85 GHz) for <inline-formula> <tex-math notation="LaTeX">$\vert \text{S}_{11}\vert \le -10$ </tex-math></inline-formula> dB is obtained, and the boresight gain is greater than 8.4 dBi across the operating band, covering both fifth-generation (5G) sub 6 GHz and WiFi bands.
An investigation of the electromechanical coupling and broadband shunt damping in composite plates with integrated piezo-patches

The popularity of laminated composite plate-like structures is increasing in various engineering applications. Piezoelectric patches with electrical circuit elements can be integrated into these structures for shunt damping applications. For analyzing the shunt damping performance of these systems, precise modeling tools are required, which consider the two-way electromechanical coupling between the piezo-patches and the host plate. This study aims to identify the system parameters which affect the electromechanical coupling coefficient, a metric for measuring the effectiveness of mechanical-to-electrical energy conversion. For that purpose, a thorough investigation is performed to determine the critical system parameters and their combined effects on the electromechanical coupling coefficient of laminated composite plates with surface-bonded piezo-patches. First, the first four natural frequencies of the electromechanical system are obtained using the Rayleigh–Ritz method for various patch sizes. Then, the electromechanical coupling coefficient variations for a different set of system parameters are presented. Later, to demonstrate the applicability of the developed methodology for a broader frequency range, four independently shunted piezo-pairs are attached to the plate. The contours of electromechanical coupling coefficient values with respect to ply angle and patch-pair size are presented for the first four modes. Finally, the vibration amplitudes are successfully reduced for these modes using the optimal system parameters.
Joint Design of Transmit and Receive Beamforming for Transmit Subaperturing MIMO Radar

We consider the joint design of the transmit and receive beamforming in transmit subaperturing multiple-input-multiple-output (TS-MIMO) systems by utilizing the prior knowledge about the locations and power of the target and inherent interferences. The joint design is solved by an iterative algorithm to maximize the output signal-to-interference-plus-noise-ratio (SINR). The proposed approach can benefit from the sum co-array and joint transmit and receive optimization. Simulation results show that the approach provides more directions of freedom (DOFs) and/or directional gain compared to the original TS-MIMO and omni-MIMO, which leads to better output SINR results and interference rejection.
A robust optimum controller for suppressing radiated sound from an intelligent cylinder based on sliding mode method considering piezoelectric uncertainties

In this study, a robust controller against the uncertainties in piezoelectric patches including sensor and actuator is designed based on sliding mode method to control the radiated sound from cylindrical shells. Accordingly, in order to extract and discretize the dynamic equations of a smart cylinder equipped with piezoelectric patches, the Hamilton’s principle and the Rayleigh-Ritz method are, respectively, used . The radiated sound is estimated by the Kirchhoff-Helmholtz integral and the acoustic structural sensing method. Furthermore, an innovative approach is proposed on sliding mode control to model system uncertainties and design robust control signals against these disturbances. Using effective control signals for each mode is the applied methodology for establishing independent sliding surfaces. In fact, it is attempted to relate between actuator matrix determinant and system control ability in generating the efficient control signals and error reduction due to actuators uncertainties. By the aid of this relation, optimization of the actuators position according to the genetic algorithm is implemented. The obtained results show that by optimizing the actuators position not only the appropriate performance of the system in controlling the radiated sound from the structure is enhanced but also the essential control voltage for each actuator is significantly decreased.
Optimal Participation of Residential Aggregators in Energy and Local Flexibility Markets

This paper presents an optimization model for Home Energy Management Systems from an aggregator’s standpoint. The aggregator manages a set of resources such as PV, electrochemical batteries and thermal energy storage by means of electric water heaters. Resources are managed in order to participate in the day-ahead energy and local flexibility markets, also considering grid constraint support at the Point of Common Coupling. The resulting model is a Mixed-Integer Linear Programming problem in which the objective is to minimize day-ahead operation costs for the aggregator while complying with energy commitments in the day-ahead market and local flexibility requests. Three sources of uncertainty are considered: energy prices, PV production and load. Adjustable Robust Optimization is used to find a robust counterpart of the problem for including uncertainty. The results obtained show that using robust optimization allows strategic bidding to capture uncertainties while complying with obligations in the wholesale and local market. Data from a real-life energy community with 25 households is used to validate the proposed robust bidding methodology.
A Review of Modern CMOS Transimpedance Amplifiers for OTDR Applications

The work presents a review of modern CMOS transimpedance amplifiers (TIAs) in the context of their application for low-cost optical time-domain reflectometry (OTDR). After introducing the basic principles behind the OTDR, the requirements for a suitable CMOS TIA are presented and discussed. A concise review of several basic TIA topologies is provided with a brief overview of their main properties. A detailed discussion is given on a representative set of approaches reported in the literature and the figure of merit (FOM) is introduced as a unified basis for performance comparison. Limitations of a single FOM as a basis for comparison are pointed out. Based on the provided discussion, some suggestions are made on the suitability of the TIA topologies for OTDR applications.
AC-Voltage Harmonic Control for Stand-Alone and Weak-Grid-Tied Converter

This article presents an ac voltage controller that can operate under a wide range of loads, thanks to its high robustness to plant-model variations. A robust voltage controller is required in a droop-controlled inverter that operates connected to a grid or in island mode with other generators. In such modes of operation, the voltage source converter can experience large load-impedance variations depending on the number of parallel generators or the grid impedance value. Concerning the controller performance, the transient response is improved by selectively minimizing the output impedance of the system at the frequencies that typically contain the largest components of the output current. Complete harmonic control is achieved due to its zero output impedance at a set of design-selected frequencies. The proposed controller only measures the output voltage, and it contains a single-loop structure that uses all available bandwidth. In addition, a fast converter-current estimator provides protection against faults and inrush output currents. The design process only requires, as input parameters, the LC filter values, the sampling frequency, and a set of harmonics where load-current circulation is expected.
The Comprehensive Circuit-Parameter Estimating Strategies for Output-Parallel Dual-Active-Bridge DC–DC Converters With Tunable Power Sharing Control

The centralized output-parallel dual-active-bridge (OP-DAB) dc–dc system is a promising candidate for achieving isolated dc–dc energy conversion with large current and power rating. To implement the flexible power sharing performance of the OP-DAB dc–dc converter, a simple tunable power sharing (TPS) strategy is proposed with the single-phase-shift method in this article. Based on the TPS strategy, the excellent dynamic performance under disturbances of input voltage for each module and load resistor can be provided. However, inaccurate circuit-parameter information always damages the power sharing performance among different DAB converters. Therefore, the comprehensive circuit-parameter estimating schemes proposed for different conditions of the OP-DAB dc–dc system including the start-up process, the working process and plugging-in a new DAB dc–dc converter, respectively. Moreover, the hot swap (plug-in and plug-out) control methods of the DAB converter without large influence on output voltage is also discussed in detail. Experimental results are obtained to verify the analysis in this article and the excellent performance of the proposed methods.
An Improved Bayesian Combination Model for Short-Term Traffic Prediction With Deep Learning

Short-term traffic volume prediction, which can assist road users in choosing appropriate routes and reducing travel time cost, is a significant topic of intelligent transportation system. To overcome the error magnification phenomena of traditional combination methods and to improve prediction performance, this paper proposes an improved Bayesian combination model with deep learning (IBCM-DL) for traffic flow prediction. First, an IBCM framework is established based on the new BCM framework proposed by Wang. Then, correlation analysis is used to analyze the relevance between the historical traffic flow and the traffic flow within the current interval. Three sub-predictors including the gated recurrent unit neural network (GRUNN), autoregressive integrated moving average (ARIMA), and radial basis function neural network (RBFNN) are incorporated into the IBCM framework to take advantage of each method. The real-world traffic volume data captured by microwave sensors located on the expressways of Beijing was used to validate the proposed model in multiple scenarios. The overall results illustrate that the IBCM-DL model outperforms the other state-of-the-art methods in terms of accuracy and stability.
Topological Charge Detection Using Generalized Contour-Sum Method from Distorted Donut-Shaped Optical Vortex Beams: Experimental Comparison of Closed Path Determination Methods

A generalized contour-sum method has been proposed to measure the topological charge (TC) of an optical vortex (OV) beam using a Shack–Hartmann wavefront sensor (SH-WFS). Moreover, a recent study extended it to be workable for measuring an aberrated OV beam. However, when the OV beam suffers from severe distortion, the closed path for circulation calculation becomes crucial. In this paper, we evaluate the performance of five closed path determination methods, including watershed transformation, maximum average-intensity circle extraction, a combination of watershed transformation and maximum average-intensity circle extraction, and perfectly round circles assignation. In the experiments, we used a phase-only spatial light modulator to generate OV beams and aberrations, while an SH-WFS was used to measure the intensity profile and phase slopes. The results show that when determining the TC values of distorted donut-shaped OV beams, the watershed-transformed maximum average-intensity circle method performed the best, and the maximum average-intensity circle method and the watershed transformation method came second and third, while the worst was the perfect circles assignation method. The discussions that explain our experimental results are also given.
Drift Compensation for an Electronic Nose by Adaptive Subspace Learning

An electronic nose (EN) is a bionic system that relies on an array of gas sensors for effective odor recognition. Since the gas-sensor drift would depress the EN performance, we proposed an adaptive Domain based subspace learning method considering both Maximizing label feature Dependency and Minimizing feature Redundancy (DMDMR) to address the EN based drift issue. Considering the inconsistent data distribution caused by drift, the proposed method learns a time-varying common subspace with similar distribution for both regular and recent drifted EN responses. In order to preserve useful classification and topological structure information simultaneously, the Hilbert-Schmidt independence criterion (HSIC) has been adopted to measure the dependence between features and labels while the feature redundancy is reduced according to the PCA criterion. An EN drift dataset acquired from a 16-gas-sensor EN system over 36 months was adopted in the experiments. To verify the effectiveness of the proposed method, we used the variations of both first and second order statistics to measure the movement of data distribution under drift condition. The results show that the data distribution in the subspace learned by DMDMR has stronger stability than the one in original space. Furthermore, the positive effects of DMDMR have been exhibited versus other state-of-the-art methods in recognition. The performance of DMDMR paradigm has demonstrated obvious superiority to other paradigms. These results prove that the proposed subspace learning approach is suitable for EN based drift counteraction and can be successfully implemented.
Modelling Of Viscoelastic Fluid In Finishing Processes

The Traditional Finishing process mostly lapping, honing, buffing, superfinishing etc contains various disadvantages like labour intensive work, high Production cost and time. Moreover, the quality of surface finish achieved is not up to the mark but in present era there is requirement of better quality of products with desired surface finish, in order to overcome this finishing issue Abrasive Magnetic Finishing and Abrasive Flow Machining process comes into the consideration. Both the Process uses a Viscoelastic media which contains an adequate amount of Polymer, gel, Oil and abrasives. Magnetic Abrasive Finishing includes polymer media with carbonyl particle which align along the magnetic field and results in effective machining. This paper includes solid modelling of the process and simulation on Ansys Fluent module and analyse the Flow parameters of the viscoelastic polymer media and its effect on material removal.
Composite Aircraft Lightning Strike Protection Damage Evaluation Using Microwave Microscopy

This article presents a new application of microwave microscopy as a diagnostic of the painted lightning strike protection (LSP) mesh used in composite aircraft skins. A new flexible probe is presented. This probe can sweep over the surface of the composite skin and detect breaks in the LSP lying underneath. It is demonstrated that shielding of the probe feeding line leads to better balancing, and consequently highly improved immunity to the presence of nearby objects. With this new approach, it is possible to localize faults as small as one cut strand under the paint. Also, this technique features the possibility to measure the paint thickness with a resolution on the order of micrometers.
Vibration Suppression of a High-Speed Macro–Micro Integrated System Using Computational Optimal Control

This article considers a dynamic modeling and computational optimal control for vibration suppression of a new high-speed macro–micro integrated system, which is mainly consisted of a macrostage and a pair of flexible microbeams (FMs). In this article, we model the FM motion by a partial differential equation (PDE) system and model the dynamics of the macro–micro integrated system based on the Hamilton's principle. Then, a computational optimal control problem for the vibration suppression of the FM is proposed. To solve this optimal control problem, we first use the assumed mode method to obtain an ordinary differential equation model based on the original microbeam PDE system. Some theoretical analysis is given to try to avoid spillover instability based on the assumed model using infinitely many modes and characteristics of a microbeam. Then, we apply the control parametrization approach to approximate the trajectory of the macrostage motion by piecewise-quintic functions and derive the gradient of the objective function with respect to the decision variables. Finally, we conclude this article with numerical simulations and experimental results to validate the effectiveness of the proposed dynamic model and computational optimization approach.
On the Design of a High-Performance mm-Wave VCO With Switchable Triple-Coupled Transformer

In this article, we present a circuit technique to design a wide tuning range (TR) voltage-controlled oscillator (VCO). The employed technique extends the TR with a minimal adverse effect on the phase noise (PN). In this context, a switchable triple-coupled transformer, implemented utilizing the topmost three metal layers of the process, is proposed to achieve a wide TR and a low PN. In the proposed configuration, the mutual coupling between the loads is increased while canceling the negative effects of the switches on the transformer performance. Depending on the possible states of the switches used in the secondary and tertiary coils, four overlapping frequency sub-bands are introduced. An extensive set of analysis is provided to support the idea. As a proof-of-concept, a 55-GHz VCO is implemented in a 65-nm CMOS process. Based on the measurement results, the VCO achieves an average PN of −111.9 dBc/Hz at 10-MHz offset over the entire frequency range and a TR of ~18%, from 50.1 to 59.8 GHz, exhibiting a figure of merit incorporating the TR (FOM $_{T}$ ) of −184 dBc/Hz at 10 MHz. The VCO core consumes 6.2 mW from a 1-V supply and, excluding the pads, occupies a compact silicon area of 0.06 mm2.
Constant Current Charging and Maximum System Efficiency Tracking for Wireless Charging Systems Employing Dual-Side Control

Wireless power transfer (WPT) systems have attracted much attention because of their safety, convenience, and environmental friendliness. For wireless supercapacitor charging, the system efficiency and charging current are highly dependent on the load that varies over a wide range. In this article, a simultaneous maximum system efficiency (MSE) tracking and constant current (CC) charging control scheme for a supercapacitor is proposed. For CC charging, a double-sided LCC topology is chosen due to its characteristic of providing a load-independent output current. Furthermore, the impact of the coil internal resistance on the system characteristics (especially the charging current) is investigated, so a semiactive rectifier is introduced on the secondary side to achieve accurate CC charging and improve the system robustness. Based on the variable-step perturbation and observation algorithm, the MSE is tracked by searching for the minimum system input dc current using a primary-side buck converter on the premise that the charging current reaches its target value. The abovementioned two control loops are independent, and mutual communication is unnecessary when they cooperate; thus, the system is simplified. The simulation and experimental results show great consistency with the theoretical analysis. The experimental system maintains the MSE of 86% during charging the supercapacitor from 20 to 50 V with 2 A.
Global Stability For Divorce In Arrange/Love Marriage Due To Extra Marital Affair

Abstract: Every person in this world is deemed to find his or her partner sooner or later. It can be love or arranged marriage and some may seek for compassion as an extra marital affair. Due to which they may face separation leading to divorce in few cases. Certain examples of negotiations are also reported where couples reunite and give their marriage a second possible chance. This scenario is formulated by a mathematical model using the system of non-linear ordinary differential equations. Also, using next generation matrix method, the basic reproduction number is computed which gives the rate of susceptible individual getting divorce. Stability analysis for equilibrium points and numerical simulations are carried out to validate the data.