Miracle-dz/UniFAR-FTUs huggingface dataset:
Deep Transfer Learning Models for Brain Tumor Classification Using Magnetic Resonance Images

The development of brain tumor cells causes the intracranial pressure inside the skull to rise, which ultimately threatens the minuscular life cycle. So, medication is the only way to increase life expectancy. It may cause death if not treated in the beginning stages. In this research paper, we aim to increase the effectiveness of magnetic resonance imaging (MRI) devices to identify cancerous brain tumor cells. We classify brain tumor cancer cells using five pre-trained convolutional neural network architecture models: ResNetl52, DenseNet201, VGG19, MobileNetV2, and InceptionV3. The ResNetl52 model was found to have the highest accuracy rate after the work was analyzed, with an accuracy value of 98.52%, which is almost 99%. In addition, the VGG19 model also showed a good accuracy rate of 98%. Other models have accuracy values of InceptionV381.30%, DenseNet20183.30%, and MobileNetV286.73%, respectively. Lower ranking means models are unable to identify brain tumor cancer cells compared to other models in the same magnetic resonance image. Based on the result, it has been observed that ResNetl52 is suitable for brain tumor cancer cell detection. The early diagnosis of malignancies before they develop physical adverse effects is benefited from this accuracy.
A Multi-Segment SVM Scheme for the Capacitor Size Minimization in SiC Devices-based Active Neutral-Point-Clamped Converters

The active neutral-point-clamped (ANPC) topology is one of the most prominent converter choices for the low and medium voltage applications. However, lowering its dc-link capacitor values remains a challenge. This paper proposes a novel multi-segment space vector modulation (MS-SVM) scheme for the SiC devices-based active neutral-point-clamped (ANPC) converter to lower the dc-link capacitor size. In this paper, the selection of most optimal switching states is investigated to achieve balanced capacitor voltages. These states are then utilized to minimize the dc-link capacitor values using the proposed switching sequence of the MS-SVM scheme. The proposed MS-SVM scheme mitigates the third harmonic voltage ripples across the dc-link capacitors in ANPC converter, which results in lower requirement of dc-link capacitor value. A detailed analysis is presented to investigate the effect of proposed MS-SVM scheme on the dc-link capacitance. Further, the performance of proposed control scheme is compared with that of the existing scheme for various load current values. A scaled-down experimental prototype of the three-phase ANPC converter is constructed to validate the performance features of the proposed MS-SVM scheme. Finally, the key experimental results are presented to demonstrate the working principle of ANPC converter using MS-SVM scheme.
A High Frequency Resonant Push-Pull Converter with a Single Integrated Magnetic Component

This Paper investigates the magnetic integration of a resonant push-pull converter operated at a switching frequency in the high frequency (HF) range (3–30 MHz). Based on the requirements arising from circuit considerations, a magnetic structure is derived that is suitable for integrating all the necessary inductive elements into one single component. An experimental demonstrator of a resonant push-pull converter operated at a 6.78 MHz switching frequency is used to verify the applicability of the proposed structure. The demonstrator features precise resonance tuning and has an output power of 420 W at the rated operating point with a dc-dc efficiency of 91%.
5-level E-Type Dual Active Bridge Converter for Photovoltaic Applications

The 5-level E-Type Dual Active Bridge (5L E-Type DAB) Converter for PV systems has been proposed in this paper. The proposed converter reduces the voltage stress of the power semiconductors, so it is suitable for high-voltage PV applications. The modulation strategy and the operating principle have been addressed for the 5L E- Type DAB converter. Moreover, a suitable design methodology for high-frequency transformers in power conversion systems is described. The proposed method covers aspects related to the design steps starting from the sizing of the primary and secondary winding, then dealing with the sizing of the core geometry and losses evaluation, up to the thermal analysis. An optimization technique based on the parameter sweep method has been integrated into the design procedure. The simulation results verify the performance of the 5L E- Type DAB converter, and the high frequency transformer design methodology.
Flying Capacitor Voltage Imbalance Protection in Multilevel Bidirectional Inverters during Surge

Input voltage surge events due to lightning strike and short-term transients such as input voltage dips are of a significant interest when flying capacitor multilevel (FCML) inverters are considered. During these fast dynamic events charge balance of flying-capacitor(s) can be compromised. This paper presents a time-efficient and reliable surge detection method to prevent FC drift during input voltage transients in FCML single-phase PFC/inverter systems. The effect on flying capacitor(s) voltage is analyzed with the help of an operational bidirectional inverter simulation. The proposed technique is implemented and validated based on a highly efficient and modern 3-level bridgeless totem-pole (BTP) power factor correction (PFC) with bidirectional grid-tied capability.
Integrated Delay-Line Based High-Resolution PFM-PWM Modulator

This article introduces a new architecture for an all-digital high-resolution variable-frequency variable-duty-cycle modulator. Constructed through digital standard-cell delay-line and simple combinatorial logic, the modulator produces PWM signals with time-resolution of a single delay-element for both switching frequency and duty-cycle attributes, thus making it a promising candidate for integration in hybrid controllers of high frequency resonant converters operating in the MHz range. Since the entire architecture is realized through standard cells, the solution also scales with fabrication technology and is described in HDL, which translates onto hardware using automated process. The modulator has been designed on a $0.18\mu \mathrm{m}$ 5V CMOS platform, totaling 0.18mm2 of effective silicon area as well as on an Altera FPGA to demonstrate the versatility of the architecture. Experiment results of the FPGA prototype are provided as well as post-layout simulations of the ASIC realization for a variety of mitigation sequences achieving time-resolution of 220ps and 200ps, respectively.
Optimal Sustainable Yield of a Renewable Resource

T1he harvesting of a renewable resource divided into classes and growing according to a deterrninistic, discrete-time, linear model is investigated. Harvesting policies involving the removal of d&fferent proportions of the classes in such a way that the yield is sustainable are considered. It is shown that the harvesting policy which maximizes the yield is one in which each class is either completely harvested or not harvested at all, with at most k exceptional classes where k is the number of linear constraints imposed on the harvester.
Evaluation of the Norton surface wave radiated by a VED in presence of an electromagnetic interface

We present a unified approach detailing the computation of electric field components radiated by a Vertical Electric Dipole (VED) near an electromagnetic interface. The dipole position and the nature of both media are arbitrary as far as the observation point is in dipole’s region. A quantitative study dealing with the appearance of the Norton Surface Wave (NSW) is also presented.
A 72GHz 64-Element Antenna-in-Package Phased-Array Module

This paper presents the LTCC package design details for a 72GHz phased array transceiver. The paper covers the module design details and the measurements results. The design is based on 8X8 patch antenna array with additional two rings of padding. The measured EIRP of the module is 39dBm. The radiation patterns show an azimuth steering of ±60° and an elevation steering of ±15°. Radiation pattern measurements are reported from 70GHz to 76GHz. The paper also presents the design considerations of the test socket used for the over-the-air measurements.
Dual-Prior Integrated Image Reconstruction for Quanta Image Sensors Using Multi-Agent Consensus Equilibrium

Quanta image sensors (QIS) are a new type of single-photon imaging device that can oversample the light field to generate binary bit-streams. The reconstruction for QIS refers to the recovery of original scenes from these binary measurements. Conventional reconstruction algorithms for QIS generally depend solely on one instantiated prior and are certainly insufficient for capturing the statistical properties over high-dimensional space. On the other hand, deep learning-based methods have shown promising performance, due to their excellent ability to learn feature representations from relevant databases. However, most deep models only focus on exploring local features while generally overlooking long-range similarity. In view of this, a dual-prior integrated reconstruction algorithm for QIS (DPI-QIS) is proposed, which combines a deep prior with a non-local self-similarity one using the multi-agent consensus equilibrium (MACE) framework. In comparison to the approaches that utilize a single prior, DPI-QIS fits the reconstruction model sufficiently by leveraging the respective merits of both priors. An effective yet flexible MACE framework is employed to integrate the physical forward model allying with the two prior-based models to achieve an overall better result. Extensive experiments demonstrate that the proposed algorithm achieves state-of-the-art performance in terms of objective and visual perception at multiple oversampling factors, while having stronger robustness to noise.
A Modified Modulation Scheme for T-type Traction Inverters to Enhance Low-Speed Range Efficiency in Electric Vehicles

In this paper, a modified three-level Space Vector Modulation (SVM) technique is proposed to increase the inverter's efficiency at low-speed operation in Electric Vehicles (EVs). Thus, an efficiency-optimized operation for the whole speed range is achieved; an industry stumble is solved. The control modification allows the efficiency optimization without the need to add/modify to the high cost power circuit of the inverter. The proposed modulation technique is applied to a three-level T-type Neutral Point-Clamped (T-NPC) topology. Based on the results achieved in this study, the proposed modulation technique improves the efficiency compared with the typical three-level SVM and the two-level six switches conventional inverters. The design, simulation, and experimental results are given in the paper to prove the merits of the proposed control scheme.
Fundamental Bound on Maximum Antenna Gain as a Sum of Characteristic Modes

Characteristic mode theory for lossy obstacles is employed to show that the fundamental bound on maximal antenna gain can be composed of a simple sum of characteristic antenna gains. This connects traditional work on bounds proposed by Harrington and modern current-density-based approaches utilizing convex optimization. The developed theory helps to understand what the true performance bound of a design region is. The paper is accompanied by an example demonstrating the working principles and verifying the developed theory.
Metasurface with Unequal Spacing Unit-cells based Antenna for Linear and Circular Polarizations

A metasurface based on unequal spacing between the rectangular-ring unit cells is used to propose a broadband, low profile, circularly polarized (CP) and linearly polarized (LP) antenna. This can be used for 5G New Radio and GNSS applications in navigation and telemetry on drone which uses remote sensing radar/lidar for survey mapping. The antenna structure comprises a stacked-metasurface based on unequal-spacing between the 7×7-unit cells, a radiating rectangular-patch, and a near diagonal line probe feed. A metasurface is considered using rectangular-ring 7×7-unit cells array with unequal-spacing’s in x- and y-directions and it is placed above a rectangular-radiator to realize a wide CP bandwidth for GNSS applications. The antenna example reaches a 3dB axial ratio of 25.3% (1.38 GHz – 1.78 GHz) with CP (3-dB axial ratio) bandwidth of 15.8% (1.51 GHz – 1.77 GHz) and gain of greater than 8.5 dBic.
Field Intensity Shaping for Biomedical Applications: Preliminary Results with Linear Superposition of Focused Patterns

In this contribution, the aim is to design the complex excitations feeding a biomedical array applicator such to ensure uniform and maximum field intensity distribution inside a given region of interest, while keeping it under control in some other regions. This issue is relevant in several applications, including hyperthermia treatment planning and magnetic resonance radiofrequency shimming. To this end, the idea of superimposing single focused patterns for field intensity shaping is further developed and discussed. In particular, a smart procedure based on the minimization of the nuclear norm is introduced and discussed for the determination of linear superposition coefficients. Note that this procedure is also relevant in satellite and radio communications, as well as in antenna array synthesis theory.
Second Harmonic Ripple Voltage Suppression for Single-Phase ISOP Solid-State Transformer by Active Power Decoupling

The solid-state transformers with input-series output-parallel structure are considered for various applications where MVAC to LVDC conversion is needed. However, due to the inherent second harmonic pulsating power in the single-phase AC system, large DC link capacitors are required to smooth the voltage ripple of all floating cells, which reduces achievable power density. The active power decoupling method can shift away the pulsating power from the DC link capacitors, leading to a significant reduction to the DC link capacitance and resulting voltage ripple. So far, the application of active power decoupling is limited to single-level converters, and little research on the impact in modular converters has been done. This paper investigates the feasibility of applying active power decoupling to solid-state transformers. The active power filter with dc-split-capacitor circuit is selected to minimize the DC link capacitance. Simulation results show that the active power filter can significantly reduce the second harmonic voltage ripple and the total DC link capacitance of the SST. A prototype of the active power filter has been built and tested to verify the design.
Revisiting the Location of Phase Center of Reflector Antennas

The aim of this paper is to provide insights into the location of phase center of reflector antennas. Analytical equations that can provide an initial estimate of the phase center are revisited and the dependency of the phase center on the reflector geometry (aperture diameter, focal length and offset height) are highlighted. These formulations, however, do not account for several factors such as the illumination characteristics, wavelength of operation, feed position, etc. In this work, the analytical equations are improved to incorporate the effect of feed illumination taper. The effectiveness of these equations are then assessed by employing Particle Swarm Optimization (PSO) to optimize the phase center based on the far-field data generated via full-wave simulations.
Asymmetrical Faults Correction Capability in a Power Insertion and Voltage Compensation System

In this work, it is presented an approach capable of improving an integrated power insertion and voltage compensation system via a nine-switch inverter (NSI). This inverter is set to correct asymmetrical faults in one of its operating modes. An instantaneous decomposition into sequence components (IDSC) method is used as a control part during the occurrence of asymmetrical faults in the grid. This is a feature added to this type of system so that it can work under asymmetry conditions. A real-time simulation system is carried out to corroborate the proposal. From the results obtained, it is concluded that the proposed additional functionality is promising, being able to add more robustness to the integrated system via NSI.
Event-based Spread Spectrum Voltage and Current Mode Digital PFM Controllers in LLC Converters

A pulse frequency modulation (PFM) technique is widely accepted for LLC converters in order to achieve reduced RMS current of the transformer. However, it suffers from varying switching frequency at steady-state under varying power levels, which makes it difficult to design an input filter to meet EMI compliance over a wide load current range. Under PFM, the switching frequency is set by the feedback loop based on voltage/current regulation requirements, and also a variation in the duty ratio is often not recommended from the RMS current point of view. This makes it difficult to identify suitable spread spectrum methods under closed-loop. This paper proposes event-based sampling and periodic perturbation methods in digital PFM control. Both voltage and current mode digital PFM architectures are proposed. By suitably modulating the control signal, spectral peak can spread over a wider frequency range with insignificant effects in RMS current and transient performance. A unified discrete-time (DT) large-signal model is developed, which can be used for different mode configurations of the LLC converter over a wide operating range. DT small-signal models are derived, which can be used for closed-loop stability analysis using the proposed methods. Conventional PFM and the proposed spread spectrum PFM techniques are compared. Hardware prototype of a 2.5 kW LLC converter is developed, and experimental results are presented to demonstrate spread spectrum using the proposed technique.
The Instability of Cross-Validated Lasso

In a situation where the number of available covariates greatly exceeds the number of observations, the fitting of a regression model to explain the connection between the response and the explanatory variables can be a challenging task. The problem can be compared to a set of equations with more unknowns than there are equations and requires application of a regularisation method to result in a useful solution. There are several such methods, with different properties. This thesis focuses on one such method: the Lasso in combination with crossvalidation (CV) to determine the level of regularisation. Specifically, we consider the method when applied on survival data where the covariates are thousands of gene expression levels. The combination of Lasso and CV proves to be unstable in the sense that repeated application of the standard R implementation often give varying results. This study’s main focus is to investigate what the causes of this instability may be. Data was simulated to map the factors that affect the stability. The simulated data sets’ properties are easy to control and the effects on the regularisation results are easily observed. The tests show that the CV process cause marked instability (varying results) when the division into training and test sets involve test sets with size larger than one. Moreover, the stability of the regularisation depends on the properties of the data set. A unique prediction result is preferable to easily choose a prognostic gene signature. However, a range of signatures from repeated regularisations can be utilised to indicate the accuracy of the suggested signature. This thesis maps several factors that affect the stability of Lasso and CV, and will hopefully contribute to caution be a warning flag when utilising the Lasso method to find a prognostic model.
Air-SIW Unit Cell with Glide-Symmetric Structures

This paper presents an air-SIW unit cell which is composed of contactless unit cells and periodic structures that modify the phase constant. The contactless unit cells are located on both sides of the waveguide to confine the propagating field into the air-SIW. The proposed unit cell which has a double-mushroom with off-center via generates a stopband between 26.5 GHz and 47.3 GHz up to a gap size of 0.1 mm. Two types of elements which modify the phase constant in the air-SIW unit cell have been analyzed. First, three slots on both broad sides of the waveguide are introduced, and later, single-mushrooms. The application of glide symmetry to theses elements are studied. Glide symmetry produces a larger operating bandwidth while maintaining linearity in the phase constant and producing a phase shift of 32o in 3.9 mm length at 40 GHz regarding an air-SIW unit cell without periodic structures.
Layout-Dominated Electro-Thermal Optimization for Multichip Power Modules with Response Surface and Fourier Series Model

The multichip high-power modules are critical components to realize power conversion in automotive powertrain and renewable energy. High power density tendency and extreme operation capability require the thermal optimization design for power modules. However, there is still a gap in the rapid electro-thermal evaluation and large-scale layout optimization for multichip parallel configuration. In this paper, a comprehensive layout-dominated electro-thermal co-design method is derived to optimize the multichip placement pattern. In the proposed method, the layout-dominated parasitic parameter is established by a hybrid method of analytic approximation modeling and response surface analysis, while the layout-dominated thermal performance is evaluated by a multilayer Fourier series method. Furthermore, the multichip power dissipation distribution is auto-solved by a set of frequency domain based electric circuit equations. Combined with the heuristic genetic algorithm optimizer, a novel successively staggered multichip layout pattern is consequently proposed and validated to achieve the current sharing and thermal balance without any additional components or advanced materials. The prototype experimental results demonstrate that the current imbalance ratio and maximum chip temperature are decreased by 50.3% and 18.1% respectively.
Broadband Isotropic Magnetic Field Probe to assess Human Exposure in the 5G FR1 band in Colombia

In this paper we present the design and evaluation of an isotropic magnetic field probe to assess the broadband contribution of the magnetic field to human exposition within the FR1 band foreseen for the deployment of the 5G technology in Colombia. This device complements the current practice in this band, based on the measurement of electric field only, which may underestimate the overall exposition in the near field of particular sources or scatterers. The frequency response of the magnetic probe is designed to correctly weight the various frequency components according to the ICNIRP 2020 guidelines, and takes into account the detailed frequency response of all the system components including the elementary sensor and the power detector. The performance of the resulting design in isotropic configuration is validated.
Folding the Feeding Network of a Millimeter-Wave Circularly Polarized Printed Antenna Array

This paper discusses the effects of folding the feeding network of printed antenna arrays operating in the Ka-band range of the spectrum. More specifically, the impact of single- and double-folded topologies on the radiation behavior of a 10-element antenna array is investigated and analyzed herein. Such impact is assessed in terms of impedance matching, circularly polarized realized gain, and axial ratio bandwidth. The proposed double-folded design features an impedance bandwidth between 26 GHz and 34 GHz while preserving circular polarization between 28.9 GHz and 30 GHz. The proposed design also achieves a maximum realized gain of 13.6 dBic, a half-power beamwidth of 11⁰, and a cross-polarization level of 14.31 dB along the direction of maximum radiation.