Miracle-dz/UniFAR-FTUs huggingface dataset:
A ZVD control based 5kW iTCM Totem Pole PFC for Server Power

A power factor correction (PFC) topology and new control methodology are introduced for high-performance cost-effective power factor correction. The topology enables the use of cost-effective component materials and zero voltage switching (ZVS) operation over the entire line cycle without adversely impacting electromagnetic interference (EMI). In addition, a new zero voltage detector circuit and algorithm are employed to enhance ZVS and total harmonic distortion (THD) without the need for a costly high bandwidth current sensor. Proof of concept is demonstrated in a 5kW prototype with a power density of 120W/in3 and a THD < 6% with no current sensor.
Fabry-Perot Resonant Cavity Antenna with Tunable Superstrate for Beam Steering Millimeter-Wave Applications

This work presents a novel beam-steerable microstrip millimeter-wave antenna. The antenna is constructed using a single-layer metamaterial superstrate, arranged on top of a wideband patch antenna in the form of a Fabry-Perot resonant cavity (FPRC). The superstrate comprises dual-array of square patches; each array consists of 9X3 square unit cells. The dual-array unit cells are placed on both sides of a parasitic patch printed on the top layer of the superstrate. By varying the electrical length of the unit cells using electronic switches controlled with DC bias, the proposed antenna achieves beam steering at -20° and +20°. Other beam directions can be achieved by changing the switching schemes of the electronic switches. The proposed FPRC based on a single patch antenna exhibits an acceptable peak gain that ranges from 7 to 9.7 dB throughout the whole operating impedance bandwidth from 29 GHz to 35.3 GHz and for different switching schemes.
A Computer-Aided Prediagnosis System for Health Prediction Based on Personal Health Data

In this era of telemedicine, the effectiveness of healthcare services is enhanced by prediagnosis based on some common health parameters. The doctor’s expertise and experience inform every clinical choice in the traditional healthcare system. Although this common technique may look reasonable at first glance, it might potentially result in unanticipated mistakes, biases, and maximized expenses, all of which could have an adverse effect on the QoS (Quality-of-Service) provided to patients. The traditional method of data analysis and prediagnosis system for clinical-decision support has to be modernized so that medical professionals may save more time. Actually, the rural parts of India still lag in the health care system as people are less aware of the disease and its precaution and suffer the most due to lack of information. In this proposed method, a computer-aided pre-diagnosis system has been designed based on machine learning (ML) algorithms that require some basic health parameters gives a correct health status of a person. A Graphical user interface (GUI) is introduced for users to enter their health data or medical values to predict their health condition. Based on the results, the user may get in touch with a doctor or nurse through their preferred mode. Moreover, it is an age-free application, i.e., it could be applicable to people of all age groups. An extensive comparison of different ML algorithms is done on real-time medical data, and it is found that support vector machine gives the best results.
Partial Discharge Characterization of Solid-Dielectric-Based Transformer Under High Frequency High dv/dt PWM Voltage for MV Applications

In this paper, the partial discharge (PD) of a solid-dielectric-based coreless transformer applied in an isolated gate driver power supply for 10-kV SiC MOSFETs is experimentally evaluated under a high frequency, high dv/dt PWM voltage. A PD test platform is built with a 10-kV SiC power module to generate high frequency, high dv/dt PWM voltage. Different PD detection equipment, including the photomultiplier tube (PMT), ultra-high frequency (UHF) antenna and high frequency current transform-er (HFCT) are adopted to detect PD signals. Experimental results validated that the solid-dielectric-based coreless transformer achieves PD free at 100-kHz, up to 75-V/ns, 5-kV PWM voltage excitation. The PD results under high frequency, high dv/dt PWM voltage and 60- Hz ac voltage are also compared.
Observer-based output feedback stabilization for a class of discrete-time switched systems with time-delay

In this paper, the design of state observer and observer-based output feedback robust stabilization for a class of discrete-time switched systems with time-delay under arbitrary switching law was studied. The certainty considered here is time-varying and norm-bounded. The switching law is arbitrary, but we assume that next activated subsystem is available in real time. The objective of this paper is to design state observers and observer-based memoryless feedback controllers for the uncertain discrete-time switched system with time-delay to guarantee the asymptotical stability of the corresponding closed-loop system by constructing an augmented system. A sufficient condition on the existence of the state observer and observer-based controller is derived by means of a Lyapunov function method together with linear matrix inequality (LMI) approach. Furthermore, the sufficient condition was turned into a feasibility problem with a set of LMIs. The corresponding observer and controller are designed in terms of LMIs. Finally, a numerical example is given to demonstrate the validity of the design approach proposed in this paper.
Development of a 96-element mm-waves Antenna Array for mMIMO Applications

We report the development of a dual-polarized and dipole-based 96-element antenna array for massive multipleinput multiple-output (mMIMO) communication systems operating in millimeter waves (mm-waves). The proposed array is composed of ±45°polarized elements based on half-wavelength printed dipoles, which are properly connected to a waveguide for enabling boresight radiation. Moreover, such array elements are directly fed by a K-connector and shielded by metallic vias, aiming at low mutual coupling levels. Experimental results, in accordance to the ANSYS HFSS numerical simulations, demonstrate bandwidth from 24.9 to 27.8 GHz, gain of 9.7 dBi gain and 60° beamwidth in both planes at 26 GHz. Regarding the MIMO figures of merit, the envelope correlation coefficient (ECC) and mutual coupling among the array adjacent elements are kept lower than 0.002 and -20 dB, respectively.
SAR measurements for back cover mobile antennas

We compare different low-profile antenna prototypes designed on the back cover of mobile devices around 2 GHz. Especially, we focus on controlling the specific absorption rate (SAR) without sacrificing the antenna efficiency. In addition, we study techniques to reduce the size of the antenna. We compare a traditional patch antenna, a sophisticated SAR-optimized design, and a patch minimized with a matching circuit. All these three options are manufactured. The measurement results show that SAR values can be decreased remarkably without compromising the antenna performance if exposure effects are taken into account in the design.
A GaN Based LCC Converter for Lithium-Ion Battery Chargers

This work describes the analysis and design of a 170W LCC converter for Lithium-ion (Li-ion) battery charger applications implemented with Gallium Nitride (GaN) technology. The solution uses an integrated System-in-Package (SiP) with two 650V enhancement mode GaN High Electron Mobility Transistors (HEMT) in Half Bridge (HB) configuration, the dedicated gate drivers and all the required protections. The LCC converter is designed to charge both 12V and 18V Li-ion batteries in CC/CV mode. The input voltage and output regulation range require a proper design of the LCC converter to shape its gain curve while maintaining the highest possible efficiency. The very high efficiency (>95%) of this design avoids the use of heatsinks and fans, allowing for a fully sealed charger with increased reliability. The efficiency and thermal performance are characterized under worst-case operating conditions in a sealed enclosure to ensure that all critical devices operating temperatures are below their rated maximum. The efficiency curves at different operating points are also provided and compared to those of a similar Silicon (Si)-based topology. When benchmarked against Si this charger shows higher efficiency in a wider regulation range, lower component temperatures and comparable system cost.
A Preliminary Investigation of EMF Exposure from Access Points in a Distributed MIMO System

Distributed multi-input multi-output (D-MIMO) is one of the most promising technology candidates for 6G infrastructure. When the access points (APs) of the D-MIMO network are placed sufficiently close, the cumulative electromagnetic field (EMF) exposure might differ significantly from the EMF exposure of a single AP. In this paper, a simple approach is proposed to assess EMF exposure using the standalone AP and a correction factor. Good agreement is obtained using simulation results. It is expected that for large AP separation distances, e.g., a few meters and above, the EMF contribution from adjacent APs might be considered negligible (less than 1 dB and even lower).
Design of Series-Resonator Buck Converter with Minimal Circulating Energy

A Series-Resonator Buck (SRB) converter is realized by adding a resonant tank in series with the series- capacitor Cs in a Series-Capacitor Buck converter. Its steady-state operation belongs to the class of quasi-resonant converters whose switch network waveforms are quasi-sinusoidal. The lack of analytical equations of the component stresses of the resonant elements stops circuit designers from identifying the operating point with minimum circulating energy. This work derives the circulating energy of the SRB converter. The understanding of the analytical relationships yields more insights into the power stage design with minimal circulating energy.
Design of a 20 kW Bidirectional Dual Active Bridge Converter for Aerospace Applications

Transportation electrification has witnessed a trend where the voltage level of the high-voltage DC (HVdc) bus is increasing due to lower cabling weight and run-time losses on the powertrain of an electric vehicle or aircraft. On the contrary, electronic sub-systems close to the passengers stay at low-voltage DC (LVdc) between 12–48 V due to the associated safety risks of being exposed to high voltages. The increase in power demand continues on the LVdc bus continues. These trends indicate the need for DC-DC converters with high voltage-conversion gains, which can efficiently deliver high currents at low voltages. This paper discusses the procedure applied to designing a 20 kW bidirectional dual active bridge (DAB) converter for aerospace applications. The interaction of design targets, design procedures, and regulatory requirements is clarified. The power loss and electromagnetic interference (EMI) modeling method applied in the design of the DAB converter is elaborated. The design optimization method and worst-case analysis for selecting critical components is discussed. Experimental verification of the DAB converter is performed, with an average efficiency of 97.1%.
A Brief Review of Recent Hierarchical Reinforcement Learning for Robotic Manipulation

Deep reinforcement learning (DRL) has become a popular learning paradigm for decision and control and has been widely applied in robot manipulation in recent years. However, due to its special learning pattern of “trial and error”, there are still some remaining problems with DRL. Such as exploration dilemma, sample inefficient, and slow convergence, are to be refined, especially when faced with complex long-horizon tasks. As a solution for these limits, hierarchical reinforcement learning (HRL) is proposed and developed by decomposing challenging tasks into multiple simpler subtasks, to efficiently solve the main task in a“divide and conquer” manner. At present, there are comprehensive HRL methods for robotic manipulation tasks, while a review is lacking. To facilitate researchers to form a general view of this field, we systematically summarize related HRL methods for robotic manipulation. This review carries out literature sortation in a novel taxonomy of subtask generation and divides HRL methods into two categories: handcrafted subtask generation and learning-based subtask generation. A great number of representative methods are analyzed in detail. In the end, we also present some important future directions for HRL.
Semimartingale detection and goodness-of-fit tests

In quantitative finance, we often fit a parametric semimartingale model to asset prices. To ensure our model is correct, we must then perform goodness-of-fit tests. In this paper, we give a new goodness-of-fit test for volatility-like processes, which is easily applied to a variety of semimartingale models. In each case, we reduce the problem to the detection of a semimartingale observed under noise. In this setting, we then describe a wavelet-thresholding test, which obtains adaptive and near-optimal detection rates.
A General Framework for Human-Drone Interaction under Limited On-board Sensing

Recent advancements in unmanned aerial vehicles (UAVs), has allowed their deployment for numerous applications like aerial photography, infrastructure inspection, search and rescue, and surveillance. Despite the potential for full autonomy, many applications still necessitate human operators for navigating complex environments and decision-making. Existing solutions often employ high-precision and simple sensors like 2-D or 3-D LiDAR, which may provide more data than necessary and contribute to increased system complexity and cost. To address these challenges and bridge the gap between full autonomy and human-controlled UAVs, this work develops a shared-autonomy framework for UAVs, leveraging lightweight, low-cost 1-D LiDAR sensors combined with mobility behaviors to obtain performance comparable to more advanced 2-D/3-D LiDAR sensors while minimizing energy, computation overhead, and weight. Our framework includes a novel state machine method that exploits the UAV mobility to compensate for the limitations of 1-D LiDAR sensors, ensuring safety and obstacle avoidance through a physics-based algorithm that transitions between teleoperation and autonomous mode as needed based on environmental conditions and safety-critical issues. Experimental validations on real UAVs demonstrates the effectiveness of this shared autonomy scheme in complex environments, and the system is further generalized to larger UAVs and prototyped with a custom sensor configuration and onboard obstacle avoidance.
WAVELET COEFFICIENT MAPPING FOR ENHANCEMENT OF CHEST X-RAY IMAGES

An approach to image enhancement of digi- tal chest radiographs is described. The method is to employ various non-linear mapping functions to different scale lev- els at the transform domain. The mapping functions are used to project a set of discrete wavelet transform (DWT) coefficients to a new set of DWT coefficients. The mapped coefficients are then inverse wavelet transformed. Our pre- liminary results strongly suggest that the proposed method offers considerably improved enhancement capability over the fast Fourier transform method and the conventional DWT method.
RAEEUCCI2023-Comparative study of Hate Speech detection using different Machine Learning Classifiers

Social media involves people getting closer to different parts of the world. The Creation of networks among different types and regions of the world consists of a clash of opinions and interests. This may lead to sharing of hate amongst people. Many social media platforms involve the concept of ‘Freedom to speech. ’ But this also incorporates some restrictions as it can lead to huge problems of spreading hate messages. To have a peaceful environment around and prevent any kind of misinformation, there is a need of having a mechanism to automatically detect hate speech. So, this research paper solves this problem by using five different classifiers with a dataset with three classes. The classes are classified as offensive speech, hate speech, or offensive speech. The classifiers involved are Gaussian Naive Bayes, Random Forest, Support Vector Machine classifier, Logistic Regression, Decision Tree Classifier, and a TF IDF -based feature engineering technique. Maximum accuracy was achieved through RandomForest which was over 90%. Moreover, accuracy can be increased by using other feature engineering techniques and a combination of classifiers.
ASegmented Electric Aircraft Drivetrain Employing 10-Level Flying Capacitor Multi-Level Dual- Interleaved Power Modules

Electric aircraft require power dense and efficient powertrains to become practical and break out of the laboratory and into the air. This work describes a full electric drivetrain, comprising six interleaved 10-level flying capacitor multi-level (FCML) dc-ac converters with high (38.4 kW/kg) specific power density and efficiency (98.95%). A global controller implements field-oriented control, and communicates through digital optical links to a local FPG A controller on each dual-interleaved FCML module (each module comprising two dc-ac converters). Success-ful demonstration on a full dynamometer test-bed with twin 250 kW electric aircraft machines is demonstrated, along with an active feedforward cancellation technique to reduce higher order harmonics.
Symmetric Tapering of Bi-Directionally Fed Leaky-Wave Antennas for Multi-Beam Synthesis

We report a theoretical investigation on the possibilities and trade-offs when tapering a bi-directional fed leaky-wave antenna (LWA) to reduce the side lobes level, when operating with the two opposite antenna ports. It is demonstrated that, for high radiation efficiency designs, the directivity can be distorted due to low aperture illumination efficiency if the LWA is not symmetrically tapered with an adequate modulation function. The theory is corroborated with simulations of modulated LWAs in substrate integrated technology.
Design of Four Plate Capacitive Coupler with Enhanced Safe Operating Region for Electric Vehicle Wireless Charging Applications

Capacitive power transfer (CPT) systems have gained popularity due to their distinct advantages over inductive power transfer (IPT) systems, including superior misalignment tolerance, lower cost, and lighter in weight. However, the fundamental issue with the CPT systems is the low coupling capacitance (usually in the picofarad (pF) region) between the transmitter and receiver plates. Owing to the restricted power transfer capability, the CPT systems are unsuitable for high-power, and large air-gap applications. In this paper, a new capacitive-based coupler using a vertical arrangement of four plates is introduced and designed to enhance the power transfer capability under misalignment conditions. In this structure, outer plates are rectangular shaped in order to improve shielding and misalignment tolerance. Inner plates are designed in a hexagonal shape to transfer higher power with minimum electric field emissions. The effectiveness of the proposed CPT coupler is validated through ANSYS-Maxwell simulations. Finally, its performance is compared with other configurations in terms of electric field emissions, misalignment tolerance, and coupling capacitance values.
MRI Segmentation of Human Brain for Diagnosis of ADHD

Brain-related disease or disorder studies in medical image processing are mainly done by analyzing images obtained from Magnetic Resonance Imaging (MRI). The most crucial stage before identifying any brain illnesses or diseases, such as lesions, Alzheimer's disease, ADHD, epilepsy, and other disorders, is the preprocessing of brain images. The Tl-weighted MRI was used in this study, and the preprocessing steps like contrast enhancement, eliminating noise, and skull extraction are performed in this project. After extensive research, algorithms for denoising and skull stripping were selected. We have implemented the Largest Connected Component (LCC) approach for skull stripping, and also proven that it is very efficient with careful evaluation. After the MRI segmentation process, the segmented grey matter aids in the diagnosis of ADHD. Performance metrics such as Dice coefficients and Jaccard Index are calculated to evaluate our work. In conclusion, this work may be beneficial in identifying between a typically developing brain and one that is affected by ADHD.
Tear and interconnect DDM with efficient multibranch-multiresolution preconditioner for the simulation of highly complex realistic problems

In this work we present the combination of a high scalability implementation of the multibranch-multiresolution preconditioner with the domain decomposition method for the electromagnetic analysis of non-conformal complex problems with different levels of multi-scale features. A numerical experiment will be shown to illustrate the great flexibility of this approach for the solution of large multi-scale objects.
Substrate-Less Vertical Chip-to-Waveguide Transition for W-Band Array Antenna Integration

This paper presents a vertical transition from a high permittivity GaAs MMIC to rectangular waveguide using bondwires as a coupling structure. The transition is advantageous for the direct integration of any off-the-shelf chip into a waveguide antenna since no modification of the GSG-pad or additional substrate is needed. An EBG structure consisting of pins is used for the packaging of the chip in order to avoid field propagation in undesired directions. The simulations results show that the reflection coefficient is lower than -10 dB and the average insertion loss is better than 0.5 dB from around 87 to 101 GHz (14% relative bandwidth).
Calculation of Ferrite Core Losses with Arbitrary Waveforms using the Composite Waveform Hypothesis

A method, the improved generalized composite calculation (iGCC) is proposed for computing ferrite core losses. This method, which is an extension of the well-known improved generalized Steinmetz equation (iGSE), applies the composite waveform hypothesis (CWH) to arbitrary excitations by using a time-varying local equivalent frequency that describes the rate of change of the magnetic flux density. The advantages of the proposed method include the ability to model materials in a wide frequency range, especially waveforms with extreme duty cycles. Measurements conducted with “EPCOS TDK N87” ferrite material (with triangular and trapezoidal excitations, across a range of temperatures) show a significant improvement over the state-of-the-art.
Analysis on Mechanism of Low Frequency Mode Small Disturbance Stability Improved Strategies Based on a PLL-equivalent Model of Weak Grid Tied VSC

Small signal instability of low frequency mode (LFM) about 1-10Hz caused by interaction of outer loop and PLL had been observed in voltage source converters operated in weak grid condition (WG-VSC). WG-VSC in traditional vector control mode has to operate in a low output power level to ensure LFM small disturbance stability (LFM-SDS). Existing studies have proposed a variety of improved control strategies by design compensation control for "outer loop-PLL" interaction to improve WG-VSC output power upper limit in LFM small signal manner. However, there is still lack of a comparison and analysis on the difference and unity of these control strategies on influence mechanism of LFM-SDS. Based on a PLL-equivalent model for analyzing the LFM-SDS mechanism of WG-VSC, this paper reveals the influence mechanism of a type of LFM-SDS improved control strategies which are realized by designing compensation control loop. And the equivalence of this type of control strategies on LFM-SDS improvement effect is point out. Simulation results with detailed switching model based on PSCAD/EMTDC have verified the theoretical analysis.